Rigid PCB Design For Manufacturability Guide - ... PCB Design For Manufacturability Guide Updated: ... CAD (Computer Aided Design) software is often used to create the layouts - [PDF Document] (2023)

Rigid PCB design guide for manufacturability

Updated October 04, 2017

Bittele Electronics Inc.

BITTELE ELECTRONICS DFM GUIDE FOR PCB DESIGNERS PAGE 1 OF 57

Document content Bittele Electronics 2017

Table of Contents 1.0 Introduction................................................. ........ .......................................... .......... ........................................ ............ ........4

1.1 Scope of application................................................ .................................................. .................................................. .... ...............4

2.0 Required documents................................................. .................................................. ................................................... ..5

2.1 Gerber files in RS-274X format......................................... . .................................................. .................................5

2.2 ODB++................................................. .................................................... .................................................... ..............6

2.3 Drilling/route file........................................ ...... .............................................. .... ................................................ .. 6

2.4 Netlist file................................................. ................................................. ................................................... ..... ........7

2.5 Centroid File / Pick-and-Place File...................................... ................................................. ...................................7

2.6 Assembly Bill of Materials (BOM) ........................................ ..................................................... .......................................7

2.7 Drawings................................................ .................................................. .................................................. .... ..........8th

2.8 Standard Manufacturing Specifications................................................. ................................................... ..... ..............9

3.0 Selection of laminate materials....................................... ....... ....................................... ..... .......................10

3.1 Material selection and properties........................................ ...... .............................................. .... .....................10

3.2 Laminate material and thickness........................................ .......... ........................................ ............ .........................11

3.3 Prepreg designation and thickness......................................... .... ................................................ .. ..................11

3.4 Copper plating (weight) for materials........................................ .... ................................................ .. .......................12

3.5 HF-Substrate....................................................... .................................................... .................................................... ..12

3.6 Mehrschichtiges Lay-Up....................................... .................................................... ................................................12

3.7 Layered lay-up recommendation................................................. .................................................. .... ....................13

3.8 Buried capacitance................................................. ........ .......................................... .......... ........................................ ...15

3.9 Material replacement (North America vs. China) ........................ ......... ....................................... ......16

4.0 Standard Printed Circuit Board Manufacturing Capabilities....................................... ..... ....................................... ... ..........17

4.1 PCB-Technology-Matrix........................................... ..................................................... ........... ...........................17

4.2 Etching factor................................................ ................................................. ................................................... ..... ......18

4.3 Drill selection................................................ ................................................. ................................................... ..... ..19

4.4 Aspect ratio................................................ ....................................................... ........................................................ ........... ....20

4.5 Ring………………………………………. . ................................................. ... ............................................... ..... ...21

4.6 Tear pads................................................ ....................................................... ........................................................ ........... 21

4.7 Lochspiel....................................................... .................................................... .................................................... 22

4.8 Ladder clearance................................................ ................................................. ...................................................22

4.9 Treatment of via holes........................................ ..... ....................................... ... ......................................23

4.10 Finished board thickness................................................. .................................................. ....................................23

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4.11 Total tolerance of the finished profile ........................................ ......... ....................................... ....... .............24

4.12 Circuit board overview................................................ ................................................. ................................................... ....24

4.13 Edge phase.................................................. .................................................. ... ............................................... ..... ....24

5.0 Capabilities of HDI technology........................................... ....................................... ......... ..........................26

5.1 Narrow track width / space................................................. ................................................... ...... ......................................26

5.2 BGA................................................ .................................................... .................................................... ................26

5.3 Mikro-Via................................................... ... .............................................. ..... ............................................ ....... ..........27

5.4 Multiple Laminations/Sequential Lamination........................................................ ................................................. ... ....29

6.0 Surface finish: options and requirements......................................... ..... ....................................... ... ...........30

6.1 HASL/LF-HASL ............................................ ....................................................... ......................................................... ........... ....30

6.2 ENTEK/OSP.................................. ....... ............................................ ...... ............................................ ... .. ....31

6.3 AGREE ........................................ ...... ....................................................... ........ .......................................... .......32

6.4 Whole-body hard gold........................................ ....... ....................................... ..... ................................33

6.5 Selective gold................................................. .................................................. ................................................... ...... .33

6.6 Double Gold (Full Body + Selective Gold)......................................... .. .................................................. .................34

6.7 Edge connector plating........................................................ .................................................. .....................................34

6.8 Wire bonding (soft gold)................................................ .... .............................................. ...... ......................................34

6.9 ENEPIG................................................... ................................................ ................................................. . ..........35

6.10 Tauchzinn................................................. .................................................... ...................................................35

6.11 Immersion silver................................................ ................................................. ...................................................36

6.12 Comparison table................................................. ....................................................... ........................................................ 37

7.0 Solder Mask: Options and Requirements................................. ........... ....................................... ......... ........38

7.1 What is a solder resist? ....................................... ......... ....................................... ....... ................................38

7.2 Types of solder resist masks........................................ ....... ....................................... ..... .....................................38

7.3 Solder mask colors................................................. ................................................. ...................................................39

7.4 Substitutes (North America vs. China) ..................................... ...... .............................................. .... ............40

7.5 Lötstoppmasken-Tenting................................. .................................................... .........................................40

7.6 Plugging the solder resist masks........................................ ....... ....................................... ..... ................................40

7.7 Peelable solder mask................................................. .. .................................................. ......................................40

8.0 Screen printing: options and requirements........................................ ..... ....................................... ... .................41

8.1 What is screen printing? ....................................... ......... ....................................... ....... ..................................41

8.2 Screen Printing Requirements......................................... ....... ....................................... ..... .......................41

8.3 Screen printing types................................................ ................................................. ................................................... .42

8.4 Screen printing colors................................................ ................................................. ...................................................42

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Document content Bittele Electronics 2017

8.5 Substitutes (North America vs. China) ..................................... ...... .............................................. .... ...............43

8.6 Multicolored silk on a printed circuit board........................................ ................................................. ... ..........................43

8.7 Serialization................................................ ................................................. ................................................... ..... 43

9.0 Electrical check.................................................. .................................................. ................................................... ...... .44

9.1 Electrical test requirements.................................................... .................................................. .... ......................44

9.2 Flying-Probe-Test................................................. .................................................... ................................................45

9.3 Fixture (Nailbed of Nails)-Test....................................... .................................................... ...................................45

9.4 Costs.................................................. .................................................... .. .................................................. .... .............45

10.0 Controlled Impedance Board........................................................ ................................................... .....................................47

10.1 Impedance Calculator................................................ ....................................................... ........................................49

10.2 Impedance Models................................................ ....................................................... ........................................................ 49

10.3 Impedance affects stacking................................. ............ ........................................ .......... ......................49

10.4 Bittele TDR calculations................................................. ................................................... ...... ...................................50

10.5 Voucher TDRs................................................. ................................................... ................................................... ..... ... 50

11.0 Panelization................................................ .................................................. .................................................. .... .....51

11.1 Reference points................................................ ................................................. ................................................... ..... .......51

11.2 Tool holes................................................. ................................................. ................................................... ..... 51

11.3 V-Score....................................................... .................................................... .................................................... ..........52

11.4 Tab-Routing................................................. .................................................... .................................................... ..52

12.0 Report Types and Report Generation................................................. . .................................................. .........................53

12.1 Final audit report for products........................................ ...... .............................................. .... .....................53

12.2 Certificate of Conformity (C of C) ........................................ . .................................................. ......................53

12.3 Test report................................................ ................................................. ................................................... ..... ...54

12.4 Solderability report................................................. ....................................................... ........................................................ 54

12.5 Cross-sectional report................................................. ................................................. ...................................................54

12.6 Impedance Report (TDR) ............................................ ....................................................... ........................................54

13.0 RoHS compliance................................................. ................................................... ..................................................... ...55

13.1 PCB raw material........................................ ....... ....................................... ..... .......................................55

14.0 Notes on assembly................................................. ................................................... .....................................56

14.1 Automated Optical Inspection (AOI)........................................................ ...... ............................................ ........ ................56

14.2 X-ray inspection................................................ ................................................. ................................................... .56

14.3 Functional test (FCT)............................................. ................................................... ...... ...................................57

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Document content Bittele Electronics 2017

1.0 Introduction The purpose of this Design forManufacturability (DFM) guide is to assist Bitteles customers with the design

Printed Circuit Boards (PCBs) that can be manufactured quickly and efficiently. Define these DFM policies

the various tolerances, rules and test procedures that Bittele adheres to when manufacturing printed circuit boards.

Addressing these issues is a win-win for all involved, both in terms of cost and efficiency

during the design phase and not during production. By providing this guide, we hope to avoid the potential

Scenario where our client has finished designing a board but later needs to revise their design due to the possibilities

Restrictions.

DFM Policies are essential to fostering customer understanding of the various options we offer

Reasons for each of these options and the limitations of Bittele's production facilities. At Bittele we specialize in this

in the turnkey production of rigid multilayer printed circuit boards with parts procurement and assembly.

For a quick overview of our manufacturing specifications see our other document on our website titled

PCB Manufacturing Specifications.

1.1 Scope

By consulting these DFM guidelines during your design process, you can plan a circuit board that conforms to them

Possibilities of Bitteles facilities. A strong understanding of our manufacturing capabilities enables our customers to do this

achieve the specific properties their designs require while maximizing efficiencies at both times

and money.

Below are some of the more notable benefits that come from design for manufacturability:

Higher quality results by working within plant capacities

Reduced throughput times by avoiding unnecessary delays

Lower labor and material costs by correcting errors

Higher first pass returns

Minimized environmental impact by avoiding waste from re-manufacturing panels

In order to fully reap the benefits listed above, our customers need to understand our capabilities in terms of the specific

Type of PCB option(s) you need. This guide is therefore divided according to the different sections

Types of options and features we offer at Bittele. These sections are as follows:

Required Documents

Selection of laminate materials

PCB manufacturing skills

capabilities of HDI technology

Surface finish: options and requirements

Solder mask: options and requirements

Screen printing: options and requirements

Electrical testing

Controlled impedance circuit board

panelization

Report Types and Reporting

RoHS compliance

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Document content Bittele Electronics 2017

2.0 Required Documents Pleasele requires various PCB design files and other forms of documentation in order to produce a printed circuit board

board and assemble the components on this board. There are two file formats that we can translate and accept

for manufacturing: ODB++ and Gerber version RS-274X.

In the OBD++ format, all the data required for circuit board manufacture and assembly are contained in the .TGZ

compressed archive. If you decide to use this format, you only have to supply the .TGZ archive

with a bill of materials (BOM) for assembly.

If you decide to use the Gerber file format, please make sure you are using the RS-274X version. This format

specifies a set of files, each file representing a type of engineering drawing, e.g.

bottom solder mask or top silk screen. Please make sure to provide a Gerber file for each design element

Your PCB layout as well as all other relevant documentation for manufacturing and assembly. When using the

Gerber format requires additional files for the board assembly, a centroid file for pick and place and a

Bill of materials with part numbers.

2.1 Gerber files in RS-274X format

RS-274X, also known as Extended Gerber or X-Gerber, is and is one of three distinct formats for Gerber files

the current industry standard. The RS-274X format is an open ASCII vector format used by standard PCB design

Industrial software for processing 2D binary images. All GerberFiles are also Computer Numerical Control (CNC)

files, and so it is possible to control a PCB maker with Gerbers since makers are CNC machines. tanner

Files describe various board images, such as copper layers, solder masks, silk screens, and paste masks. These dates

includes the traces, vias, pads, component footprints and planes, as well as drilling and milling data.

RS-274X is the middle child of the three Gerber file formats. The oldest format for Gerber files is RS-274D, or

Standard Gerber, now generally deprecated in favor of the Extended Gerber format. The data

in RS-274X is much more comprehensive than RS-274D because the RS-274D format retains many of its critical properties

Information separate from the main data file. The RS-274X format offers several advantages over the current one

obsolete RS-274D, including high-level commands and controls, allowing for more precise machine plotting.

Gerber X2, the third and latest Gerber format, was released in February 2014. It's completely backwards-

compatible with RS-274X format, but includes some extra metadata to avoid ambiguity. Gerber X2 does not have

however, it is widely used in industry and RS-274X remains the standard for now.

PCB layouts are created using a CAD (Computer Aided Design) system and saved in RS-274X format

The Gerber kit contains the complete description for each individual layer of the circuit board. Usually the CAD system

used to output a Gerber file for each relevant layer. These Gerber files can be loaded into a computer.

Aided Manufacturing (CAM) system to provide data for each step of the PCB production process.

In accordance with industry standards, we at Bittele accept the RS-274X Gerber format. This enables our customers

use their CAD design tool of choice, provided they can output their finished design files to Gerber

Format. The Gerber RS-274X format contains separate files for the different copper layers, silkscreen layers,

Solder mask layers and mill/drill sites included in a given design. Along with your Gerber files, you

should send PCB fabrication drawing and PCB assembly drawing and BOM for you

Command. See Table 1 below for a brief description of each of these file types:

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Document content Bittele Electronics 2017

Table 1

PCB Manufacturing Drawing Printed Circuit Board manufacturing information

PCB assembly drawing PCB components on the board assembly information

Bill of Materials Table with information on all components to be placed on board

Information about the electrical connectivity of the netlist component

Gerber Files group of files below

Pass PCB copper design file information e.g. B. traces, pads, further

Drill Files Information about drill holes in the PCB design

Solder mask files Information on areas that should not be covered with solder mask, e.g. upholstery, holes

Board Outline File size and shape of boards

Information on surface markings of screen printing plates

2.2 ODB++

ODB++ is a printed circuit board (PCB) manufacturing database that stores various data in a hierarchy of files

and file folder. Some common operating system commands can be used to conveniently transfer data

to create a single compressed file while preserving the hierarchy information. This compressed file that contains

Printed circuit board (PCB) design information can be sent directly to PCB fabrication and assembly

companies like Bittele. ODB++ stands for Open Data Base with the suffix ++ added in 1997 when

Component Descriptions have been enabled. ODB++ was developed and distributed by Valor Computerized

Systems, but was later acquired by Mentor Graphics in 2010.

The vast majority of electronic devices contain a circuit board that serves to house the electronic components within

to power the device and also to connect these components together in certain ways. Computer Aided Design

(CAD) software is often used to create the layouts for these PCBs and this layout information then needs to be

transferred to a photolithographic computer-aided manufacturing (CAM) system. These CAD and CAM systems

are generally produced by different companies and must therefore use an intermediate file format, such as

ODB++, for successful data exchange. ODB++ has two versions: the original (owned by Mentor), and an XML

Version called ODB++(X) donated to the IPC organization by Valor Computerized Systems.

At Bittele we can work with ODB++ files of revision 7.0 or lower; There are no restrictions on the design tool

Used for PCB layout as long as the design can be translated into ODB++ format files. Apart from that, we Bittele

cannot accept ODB++(X) files. If you are having trouble outputting your ODB++ files, please direct your

.CAM or .PCB files to us and we will attempt the conversion on your behalf.

2.3 Drill/Route File

Drill files define the size and coordinates of all holes to be drilled in a PCB design. These files can be used

Controlling a drilling machine that creates holes for VerticalInterconnect Access (VIA), assembly, and THT

component placement.

On a standard 2-sided PCB, drill files are required to allow the CNC machine to create accurate vias. For more

In complex multi-layer boards, many of the holes will be microvias, which tend to only go through a few layers

than the entire board. These types of holes are also known as blind and buried vias. We need a separate one

Drill file with a unique name for each pair of planes that will be included in your design.

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Document content Bittele Electronics 2017

For example: let's say you have a 4-layer board with most of the vias running from top to bottom

below and some buried vias extending from layer 1 to layer 2. In this case you should have two drill files,

with one named Drill_1-4 and another named Drill_1-2.

Route files are a type of file that define the electrically conductive copper traces, colloquially known as

routing, on a PCB design. These files are used to control a fabrication machine to lay copper traces

on a circuit board.

Regarding submitting drill and route files to Bittele: If you are using the ODB++ format, drill files and routes

Files will both be included in the .TGZ compression file. If you choose the Gerber RS-274X format, then

separate drill files and route files must be provided in RS-274X format.

2.4 Netlist File

Netlist files contain the connectivity information for an electronic circuit. A netlist file is a collection of several

associated lists; a list for each group of electrically connected pins. This file is generated from the circuits

schematic design, and it is used in PCB layout to determine which component pads to connect

Traces of copper on the finished circuit board

At Bittele, we request a netlist file for electrical testing of your bare printed circuit boards; We ensure an exact match

between the actual connectivity on your PCB and that of your netlist file for each board that leaves our factory.

The ODB++ format includes your netlist file by default, so no separate deployment is required.

If you are using the Gerber RS-274X format, you will need a separate IPC356 format netlist file.

2.5 Centroid file / pick-and-place file

We need a centroid data file, also known as a pick and place file, to accurately assemble a circuit board. The

The main purpose of centroid data is to store information about the position and orientation of all surface mounts

Technology (SMT) components on a printed circuit board design. Centroid files contain data on reference identifiers,

XY positions, rotations, component packages and placement on either the top or bottom of the board.

Reference designation Short alphanumeric code assigned to each part in the layout (R12, C17)

Component Value/Package Component part numbers, part values, and package size

Layer Either the top or the bottom

XY Position Cartesian coordinates starting from the origin

Rotation Described part orientation in degrees (0, 45, 90, etc.)

2.6 Assembly Bill of Materials (BOM)

The BOM is a list of all the parts needed for PCB assembly and maps those parts to the

Reference designator in PCB layout. We need this list in Microsoft Excel format. If multiple instances

of the same part are used on a board, then they will all be listed on one line of the BOM with their respective ones

Reference designator and total quantity. The following information includes the bill of materials, incomplete bills of materials

may be acceptable, however it is always best to include all of the following information in your bill of materials

Minimize the risk of bad purchases.

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Document content Bittele Electronics 2017

Item # - Unique item number for each component (1, 2, 3)

Ref Des Matches the BOM item to the location of the PCB layout

Amount Amount of this component needed for each board

Manufacturer The name of this component manufacturer

Manufacturer Part Number - The part number assigned to a component by the manufacturer

Description Short component description

Package Package size (e.g. 0805) or type (e.g. BGA, QFN)

Enter SMT or THT

Your Instructions Any special requirements you have for this part

We provide a sample bill of materials on our website that can be used as a basis for your bill of materials.

2.7 Drawings

Engineering drawings are not strictly required for all PCB fabrication and assembly projects, but they can help

Make your intentions clearer to our production team, especially regarding special requirements. We

For projects with a high number of layers or components, we recommend that you include construction drawings.

2.7.1 Printed circuit board production drawing Printed circuit board production drawings contain only the information that is required for the production of the printed circuit board. The

information such as project name, panel dimensions, panel thickness, tolerances, material,

Copper weight, number of copper layers or surface finish. This can be a list of notes next to the boards

Artwork or listed in a separate file. Other special information may also be included during manufacture

drawing, such as B. Requirements for controlled impedance, via-in padtenting, gold-plated edge connectors, and so on

An.

Figure 1: Assembled circuit board

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Document content Bittele Electronics 2017

2.7.2 PCB assembly drawing PCB assembly drawings contain the information needed to assemble the various components

a circuit board. Basic component information such as location and orientation is provided with this drawing

special requirements, such as B. Height Limit. Three-dimensional representations could also be included for clarity

special requirement areas, but are not required for typical boards.

2.8 Standard Manufacturing Specifications

The following list are the parameters we need to manufacture your design. Please provide them

Information when you request a quote to properly evaluate your project.

Project name PCB name and version number

Dimensions [inches] board length and width

Number of layers 2, 4, 6, 8, 10, 12, 14, 16 layers

Total Thickness [inches] Plate thickness for a plate with all layers included

Finish Example: HASL, ENIG, Immersion Tin, Immersion Silver

Solder Mask Indicates the desired solder mask color for your circuit board and on which sides of the

Circuit board to which the solder mask is applied

Extended parameters that can also be specified include

Profiling Specify any paneling requirements for your project

Impedance Control Do you need a specific impedance for RF transmission lines?

Material (substrate) Example: FR4 or IT-180A

Silk Screen (Legend) Indicates the desired silk screen color for your circuit board and on which sides

the plate to which screen printing is applied

Testing Electrical testing is standard on all our orders and cannot be excluded for quality assurance.

Guidelines for Handling and Storage of Printed Circuit Boards Any specific information on safe handling

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Document content Bittele Electronics 2017

3.0 Selection of Laminate Materials Laminates are the main material used in PCB manufacture and different laminates have different properties.

services and associated costs. This section outlines the different laminate options that can be selected

for your PCB design and gives a brief comparison and contrast between these options.

3.1 Material selection & properties

As a first step in this DFM guide, we are providing you with information to help you choose a suitable one

Laminate material that meets your performance needs while minimizing manufacturability issues. We

Start here as the cost of raw laminates is generally the largest single component of PCB manufacturing costs.

The key factors to consider when choosing a laminate material for a PCB design are cost, quality,

and the lead time. Due to the amount of material required for PCB manufacture, it is important to optimize for size

your designs; Even a small difference in size can result in a significant difference in cost.

Different materials have different costs and properties, but high quality laminates do

usually more expensive. Below are some of the key features to look out for and when

Comparison of the properties of different laminates:

Tg = glass transition temperature Temperature at which a critical change in physical properties occurs.

Laminates transition from a hard, glassy material to a soft, rubbery material

Td = decomposition temperature - temperature at which the laminate chemically decomposes

Dk = dielectric constant (also known as r in electromagnetics) Specifies the relative permittivity of

an insulator material that refers to its ability to store electrical energy in an electric field. For isolating

For purposes a lower dielectric constant material is better and in RF applications a higher dielectric constant

may be desirable

Df = Dissipation Factor Indicates the efficiency of an insulating material by showing the rate of energy loss

for a specific type of vibration, such as mechanical, electrical or electromechanical vibration

Our manufacturing facilities are located in China, so it is advisable to choose high-quality local laminates in order

Minimize shipping cost and lead time. The Shengyi S1000-H (Tg150) laminate is generally our standard choice

for a high performance, medium Tg laminate. Shengyi S1000-H is comparable to Isola FR406 (Tg 150), a standard

North American laminate option. As shown in Table 2 below, FR406 slightly outperforms Shengyi S1000H

in terms of dielectric constant and dissipation factor, but some customers may be willing to compromise on this

Factors for lower costs and/or faster delivery time.

Table 2

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Shengyi S1141 (TG 130) is a good alternative to reduce the cost of your project at the expense of quality.

In cases where higher quality is required, we recommend ShengyiS1000-2M (TG 170), which is the closest

Quality according to Isola FR406 (Tg 170). Where quality has the highest priority, we recommend using ITEQ

IT180A (TG 180) which is also RoHS compliant. ITEQ IT180A (TG180) is qualitatively comparable to Isola 370HR

(TG 180). At Bittele, we recommend using Shengyi S1000H (Tg130) for typical projects. We would

we recommend using one of the higher quality laminate materials if any of these three conditions occur:

1) If the PCB design has 8 or more layers

2) If the copper plate is heavy and has a copper weight greater than 3 ounces

3) When the circuit board is thin with board thickness less than 0.5mm

3.2 Laminate Material and Thickness Table 3

Core material thickness including copper (mm.)

Copper weight (oz.)

0,145mm. H/H oz.

0.17 mm. 1/1 ounce.

0,185mm. H/H oz.

0.2 mm. 1/1 ounce. or H/H oz.

0.25 mm. 1/1 ounce. or H/H oz.

0,3mm. 1/1 Unze. oder H/H oz.

0,4mm. 1/1 Unze. oder H/H oz.

0.5 mm. 1/1 ounce. or H/H oz.

0,6mm. 1/1 Unze. oder H/H oz.

0.7mm. 1/1 ounce. or H/H oz.

0,8mm. 1/1 Unze. oder H/H oz.

0,9mm. 1/1 Unze. oder H/H oz.

1.0mm. 1/1 ounce. or H/H oz.

1,1mm. 1/1 Unze. oder H/H oz.

1.2 mm. 1/1 ounce. or H/H oz.

1.5 mm. 1/1 ounce. or H/H oz.

1,6mm. 1/1 Unze. oder H/H oz.

2.0mm. 1/1 ounce. or H/H oz.

2.2 mm. 1/1 ounce.

2,4mm. 1/1 Unze.

2.5 mm. 1/1 ounce.

3.0 mm. 1/1 ounce.

Table 3 lists the core material thickness with copper weight for regular FR4 material

1/1 = 1 ounce. Copper per square foot on BOTH sides of sheet

1/0 = 1 ounce. Copper per square foot coated on only 1 ONE side of sheet

H/H = 0.5 oz. Copper per square foot coated on both sides of the sheet

0/0 = UNCOVERED (NO copper).

3.3 Designation and thickness of the prepreg

Prepreg is a bonding material used in the manufacture of multi-layer printed circuit boards and exhibits the same after curing

Properties like the core/base layer materials. Prepregs have different glass styles 106, 1080, 3313, 2116 and 7628

used by record manufacturers. Panel manufacturers use a variety of prepreg glass styles. These styles include 106,

1080, 3313, 2116 and 7628. Restrictions may apply to the number and types of prepregs. It is therefore best to contact us

a Bittele representative for more details.

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Table 4

Prepreg/Glass Styles Pressed Thickness (mm) Prepreg Resin Content

106 0,05mm. Ca. 73%

1080 0,075mm. Ca. 65%

3313 0,09mm. Ca. 57%

2116 0,115mm. Ca. 55%

7628 0,185 mm. Ca. 46%

7628H 0,195 mm. Ca. 51%

3.4 Copper Cladding (Weight) for Materials Copper clad FR-4 laminate materials are measured using ounces (oz.) of weight per square foot.

0,25 oz. = 0,00035 (8,75 m)

0,5 oz. = 0,0007 (17,5 m)

0,75 oz. =0,00105 (26,25 m)

1,0 oz. = 0,0014 (35 m)

2,0 oz. = 0,0028 (70 m)

3,0 oz. = 0,0042 (105 m)

4.0 oz. or more = 0.0056 (140 m) or more

Bittele Electronics is capable of manufacturing multilayer PCBs with a maximum copper weight of 10oz.

copper weight of 4 oz. or higher require an additional estimate and may also affect delivery times.

3.5 HF-Substrate

For high frequency applications, Bittele Electronics stocks Rogers RO4350B as the standard RF substrate. We

offer core thicknesses of 10mil, 20mil or 30mil in stock and the copper weight can be 0.5oz/0.5oz or 1oz/1oz.

Other sizes available by special order with additional lead time are 6.6 mil, 13.3 mil, 16.6 mil, 60 mil. The dielectric

This material's constant is 3.76 at 1 GHz and averages 3.66 for 8 GHz to 40 GHz. See below for more details

the material data sheet here. Additional material types may be available with additional lead upon special request

Time.

3.6 Multi-layer structure

Multilayer panels have some physical properties that must be considered by both the designer and the designer

Manufacturer to ensure quality construction. Multilayer board designs should be even numbered

of layers for best quality. Select the dielectric thickness of each layer from the core or prepreg thicknesses provided

are listed in Table 3 and Table 4. For possible combinations, please contact our Bittele manufacturing team

are suitable and achievable dimensions and tolerances.

It is recommended that multi-layer constructions balance the build relative to the Z-axis center to minimize warpage and deflection

Twist. In other words, a layer construction list should be read top-down the same way as bottom-down

Top. Dielectric thickness, copper thickness and location of layers, median, z-axis must be balanced. If the

Multi-layer design rules are followed, the PCB should meet the specification for the maximum allowable deflection

https://www.rogerscorp.com/documents/726/acm/RO4000-Laminates---Data-sheet.pdf

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and twist of 0.25 mm per 25 mm (1%) or better. It is also advantageous to balance the circuit distribution between them

the front and back of the board as much as possible. This is more of a problem with thicker copper weights.

The thickness tolerance increases as the total thickness of a multilayer board increases. You should specify a

Tolerance of 10% for total thickness thicker than 1mm, or +/-0.1mm for 1mm thickness or

Thinner. In addition, you must always specify where the thickness measurement is to be taken.

3.7 Recommendation for multi-layer construction

At Bittele Electronics, we can produce multi-layer circuit boards with up to a maximum of 40 layers. PCBs with more

For more than 20 shifts, an additional estimate is required before production can begin. Below are our recommendations

Stackups for normal plate thickness of 62mil. At Bittele we offer custom stack-ups, please let us know which ones

you need and our CAM engineer will check the feasibility.

2 layer stack

Layer Order Layer Name Material Type Thickness Copper Weight

1 Top Kupfer 1,4 mil 1 oz.

Core 57.7M

2 Bottom Copper 1.4 mil 1 oz.

Finished Board Thickness: 62 mil +/- 10%

4-layer construction

Layer Order Layer Name Material Type Thickness Copper Weight

1 Top Kupfer 1,4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

2 inner 1 copper 1.4 mil 1 oz.

Core 36.6M

3 Inner 2 Copper 1.4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

4 Bottom Copper 1.4 mil 1 oz.

Finished Board Thickness: 62 mil +/- 10%

6-layer construction

Layer Order Layer Name Material Type Thickness Copper Weight

1 Top Kupfer 1,4 mil 1 oz.

Prepreg (2116) 4.5 Mio

2 inner 1 copper 1.4 mil 1 oz. Core 16.9M

3 Inner 2 Copper 1.4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

4 Inner 3 Copper 1.4 mil 1 oz.

Core 16.9M

5 inner 4 copper 1.4 mil 1 oz.

Prepreg (2116) 4.5 Mio

6 Bottom Copper 1.4 mil 1 oz.

Finished Board Thickness: 62 mil +/- 10%

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8-layer construction

Layer Order Layer Name Material Type Thickness Copper Weight

1 Top Kupfer 1,4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

2 inner 1 copper 1.4 mil 1 oz.

Core 5.1M

3 Inner 2 Copper 1.4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

4 Inner 3 Copper 1.4 mil 1 oz.

Core 5.1M

5 inner 4 copper 1.4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

6 inner 5 copper 1.4 mil 1 oz.

Core 5.1M

7 Inner 6 Copper 1.4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

8 Lower Copper 1.4 mil 1 oz.

Finished Board Thickness: 62 mil +/- 10%

10-layer construction

Layer Order Layer Name Material Type Thickness Copper Weight

1 Top Kupfer 1,4 mil 1 oz.

Prepreg (2116) 4.5 Mio

2 inner 1 copper 1.4 mil 1 oz.

Core 3.9M

3 Inner 2 Copper 1.4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

4 Inner 3 Copper 1.4 mil 1 oz.

Core 3.9M

5 inner 4 copper 1.4 mil 1 oz.

Prepreg (1080*2) 5.9 Mio

6 inner 5 copper 1.4 mil 1 oz.

Core 3.9M

7 Inner 6 Copper 1.4 mil 1 oz.

Prepreg (2116*2) 9.1 Mio

8 inner 7 copper 1.4 mil 1 oz.

Core 3.9M

9 Inner 8 Copper 1.4 mil 1 oz.

Prepreg (2116) 4.5 Mio

10 Lower Copper 1.4 mil 1 oz.

Finished Board Thickness: 62 mil +/- 10%

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3.8 Buried Capacitance

Buried Capacitance is a PCB manufacturing method that creates a decoupled capacitance by inserting a

very thin dielectric layer inside a printed circuit board. Adding buried capacitance to a board eliminates the need for decoupling

Capacitors, freeing up more PCB real estate by eliminating redundant pads and conductors. have a lower one

The number of components on a PCB lowers costs and simplifies and reduces PCB assembly as well

the number of steps required. New technologies like this give designers a greater freedom that allows

them to develop higher performance or equivalent performance PCBs in a smaller board size. Finally use

Buried capacitance can also reduce noise and high-frequency electromagnetic interference to improve the circuit board

Quality. Figure 2 (below) shows an 8-layer buried capacitance board.

Figure 2: Buried capacitance stack (eight layers)

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3.9 Material Replacement (North America vs. China)

China Substitute Materials

Shengyi S1141 (TG 140)

Td 300, Dk 4,2, Df 0,015

Link to material data sheet

Shengyi S1000H (Tg 150)

Td 325, Dk 4,38, Df 0,015

Link to material data sheet

Shengyi S1000-2M (TG 170)

Td 340, Dk 4,28, Df 0,017

Link to material data sheet

ITEQ IT180A (TG180)

Td 350, Dk 4,3, Df 0,015

Link to material data sheet

North American Laminates

Island FR406 (TG 170)

Td 300, Dk 3,93, Df 0,0167

Link to material data sheet

Isola 370HR (TG 180)

Td 340, Dk 4,04, Df 0,021

Link to material data sheet

Table 2

Finally, in addition to the laminate quality, we also have to consider the cost of materials and the delivery of the available laminates

Lead time taken into account. Since Bittele's PCB manufacturing and assembly facilities are located in China, the cost of

North American laminate import would be higher and lead time longer as shown in the table above.

Therefore, from this comparison table, we can conclude that using local spare is preferable due to the lower value

Material costs and shorter delivery times.

Table 5

Material Price Matrix Cost in China Lead Time Cost in N.A. lead time

370 HR 130% longer 100% shorter

FR408HR 150% longer 120% shorter

S1141 70% shorter 120% longer

S1000-H 75% shorter 120% longer

S1000-2 70% shorter 120% longer

IT180A 80% shorter 140% longer

China USA China USA China USA China USA

S1141 FR406 S1000-H FR406 S1000-2 FR406 IT180A 370HR

Td (TGA at 5% weight loss) NA 300 N/A 300 N/A 300 350 340

Dk (50% resin at 2 GHz) 4.2 3.93 4.38 3.93 4.28 3.93 4.3 4.04

Df (50% resin at 2 GHz) 0.015 0.0167 0.015 0.0167 0.017 0.01670.015 0.21

RoHS J J J J J J J J

Tg 130 Tg 180Tg 170Tg 150

http://www.syst.com.cn/UploadFiles/file/201603%E7%A1%AC%E6%9D%BF/201603291124204350671-%20s0401-en.pdfhttp://www.syst.com.cn/UploadFiles /file/201603%E7%A1%AC%E6%9D%BF/201603291132553890451-1000HB-en.pdfhttp://www.syst.com.cn/UploadFiles/file/201603%E7%A1%AC%E6%9D %BF/201603291206583450426-00%202MB-en.pdfhttp://www.westak.com/downloads/P_IT180A.pdfhttp://www.isola-group.com/products/fr406/http://www.isola-group .com/products/370hr/

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Document content Bittele Electronics 2017

4.0 Standard PCB Manufacturing Capability The PCB manufacturing capability is a summary of the PCB fabrication and assembly of a PCB manufacturing facility

Options, limits and tolerances on what PCBs can be made. This section introduces ours

Manufacturing and assembly capabilities, as well as cost and lead time requirements. Customers often will

Make PCB design decisions based on manufacturer manufacturing capabilities. With the knowledge of our

Capabilities, limits and tolerances, errors can be reduced and time saved. All boards should be there

These guidelines are essentially designed for manufacturing and are intended to ease the transition from design to manufacturing

and assembly.

4.1 PCB-Technologiematrix

A brief overview of the technological specifications that determine whether a PCB can be manufactured by Bittele is given

in Table 6 below. For a more comprehensive list of our capabilities see our other document PCB

Manufacturing Specifications.

Table 6

Trait Bittele ability

Minimum trace width 4 mil (but increases with higher copper weight)

Minimum hole size 0.1 mm (laser) 0.15 mm (mechanical)

Minimum distance 3 mil (but increases with higher copper weight)

Panel thickness limits 0.2mm - 6mm for 2-layer panels

Maximum allowable copper weights 0.5 oz (0.685 mil) to 20 oz (27.4 mil)

Maximum and minimum board size 0.2 x 0.2 to 14 x 20 (or larger Forbare boards)

Layer Count - The number of layers in a multi-layer PCB Up to 40 (less than 20 recommended)

Special features Goldfinger, several surface finishes, etc.

Key PCB factors also influence each other, increasing or decreasing relative to each other.

Track width and pitch affect each other, as track width increases, track pitch

decreases, and its impedance also decreases.

The minimum hole size and panel thickness affects the aspect ratio as the minimum hole size decreases

or the panel thickness increases, the aspect ratio increases.

Hole sizes affect the annular ring in hole size and the distance between holes to other features

the ring enlarges and the space becomes smaller.

Copper weight affects impedance. As copper weight increases, impedance decreases.

4.1.1 Prices Bittele Electronics offers base prices for the manufacture and assembly of printed circuit boards. These start with default values,

and can be customized to suit your needs. The final cost will be affected by material selection and component costs.

Material and component prices are constantly changing due to fluctuations in market prices. Some factors that

Impact on the manufacturing and assembly costs of printed circuit boards:

PCB Size – While the PCB is larger than 50mm x 50mm, a smaller PCB can reduce costs while a larger PCB will reduce costs

boards cost more. Boards less than 50 x 50mm are more complex to manufacture.

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Number of Layers - The price increases with the number of layers.

Laminate Materials - A laminate material with Tg 140 would be inexpensive while laminate is of a higher quality

with Tg 180 costs more.

Copper Weight - Copper weight is divided into inner and outer layers. A higher copper weight together

with a larger number of layers, the cost of production increases.

Goldfinger - used to connect circuit boards with sockets on them like a PC motherboard. golden fingers

increases the price based on the quantity and the number of pages Goldfinger requires.

Via in Pad - Holes under the component pads increase cost by adding an extra step to manufacturing.

Blind, Buried, Micro-via- Specialty vias require additional processing steps and multiple lamination steps.

Panel Thickness - With a standard panel thickness of 0.063 inch, total cost will vary depending on

the desired plate thickness.

Surface Finishing - Bittele Electronics is proud to offer you a choice of Gold Immersion, HASL and Lead Free

HASL, OSP and Silver Immersion at no additional cost. Hard gold plating, selective gold plating, etc. will have an effect

pricing.

Impedance Check - calculates electrical impedance and buried impedance. Tighter manufacturing

Tolerance to meet requirements increases costs. TDR voucher and report are included.

V-Scoring, Tab Routing and Mouse Holes - Used to form multiple boards into one panel without additional elements

Fee for services when multiple boards all have the same design. When multiple PCB designs are needed

Panelization, additional fees apply for this service.

Special features - sinkholes etc.

If the requirements of the circuit board do not meet the capacity of the factory; e.g. number of layers, board

Thickness, panel size, surface finish and features; then the cost will be affected.

4.1.2 Lead Time Lead time is an estimate of the time it takes to complete an operation or process from start to finish

End. One type of lead time is material supply lead time, which is the estimated time required for board assembly

Materials arriving at the Bittele non-standard materials facilities. Another type of lead time is the

Manufacturing Lead Time, an estimate by our manufacturing facilities of the time required for manufacture and assembly

a board in question. Our minimum lead time for bare boards is 5 days but with more layers and up

Quantity lead time will be extended. The lead time of your project will be stated in your quotation. For turnkey orders, the

including production, parts sourcing and assembly Standard lead time is 14 days but you can ask one of our staff

Sales representative via express service. Factors beyond shifts and quantity affecting delivery time include:

Copper Weight - each additional ounce over 3oz. adds an additional lead time

Oversized or very small boards require an additional one day lead time

Black soldermask requires an additional one day lead time for bareboards only (non turnkey)

4.2 etching factor

What is etching? Printed circuit board etching is the process of selectively removing unwanted copper from copper-clad substrates of a printed circuit board

two main methods of removing the copper cladding are mechanical etching and chemical etching.

Mechanical etching uses a CNC machining tool with a special cutting tool to remove narrow strips of copper

from the boundary of each pad and trace to electrically isolate them from the rest of the copper foil.

Chemical etching uses a caustic solution to dissolve unwanted copper. A protective layer is cut to match

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the Gerber design files of the circuit boards and then block the applied chemicals to get the required pads and traces

to stay intact. At Bittele, we use chemical etching as a normal process because of its precision and efficiency.

What is the etching factor? To create the copper layer features designed by our customer, we use a caustic solution to remove them

unwanted copper area, leaving the desired pattern. But when etching, the caustic solution becomes

As well as etching the unwanted copper, etch the walls of the copper features of the design (ie

undercut). Figure 3 (below) illustrates the result. The ratio D/C is equal to the etch factor. So the depth

to which the etch occurs is proportional to the copper layer thickness (i.e. thicker copper has a deeper etch).

This is because thicker copper requires longer exposure to the chemicals to be completely removed

This gives the corrosive chemicals more time to etch the walls before washing away.

The etch factor for PCBs manufactured by Bittele depends on whether the layer is inside or outside the PCB.

The etch factor for outer layers is 1.4 and the etch factor for inner layers is 2.5.

Figure 3: Profile view of the etch dimensions

4.3 Drill selection

4.3.1 Hole Diameter We Bittele can drill holes of the sizes listed below.

Table 7

Available mechanical hole size 0.15mm - 6.0mm

Available laser hole sizes 4 mil - 6 mil (0.1mm - 0.15mm)

Note: If the hole size is larger than 6.0mm, we can also build them as cutouts (by milling), but the tolerance needs to be +/- 0.15mm

Holes drilled in circuit boards can either be plated with copper or left bare. The plated holes will be

covered with copper on their walls after copper layers have been etched, and they are used to form electrical ones

Connections from one copper layer to another in a printed circuit board. Unplated holes are usually used for positioning or

assembly and therefore do not require copper on their walls. Please indicate your choice in your Gerber files. Your

Circuit design program should be able to help with this.

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For multilayer boards, holes can be categorized based on their depth into through holes, blind holes, and buried holes

holes. Through holes will be drilled through the entire board from the top and bottom layers, blind holes will be

drilled from an outer layer to an inner layer, and buried holes are drilled from an inner layer to another inner layer

Layer. See Section 5.3 Micro-Via for further explanation of these hole types. A separate borehole level is

necessary for different hole depths up to a maximum of 4 types. For example a board with through

Holes and buried vias between layers 2 to 3 and 4 to 8 require 3 different layers with hole positions and

sizes.

4.3.2 Hole size tolerance The hole size tolerance is the permissible range of deviation for the drilled hole of a printed circuit board from the specified hole size

the PCB design.

Press-fit holes are tighter tolerance plated holes used for through-hole components that are not

soldered to the board.

At Bittele we can control the hole size tolerance in Table 8 below.

Table 8

Plated Holes +/-3mil

Press-in holes +/-2mil

Unplated holes +/-2mil

4.3.3 Slot Size Tolerance Slots are special holes that have a different length than their width. And usually if their length is longer than

twice their width, we call them long slits, otherwise we call them short slits.

At Bittele we can control the slot size tolerance as per Table 9 below.

Table 9

Plated short slots +/-0.15mm

Uncoated short slots +/-0.1mm

Plated long slots +/-0.1mm

Uncoated Long Slots +/-0.075mm

4.4 Aspect Ratio

The aspect ratio is calculated by dividing the maximum plate thickness by the minimum drill hole diameter

specified for this board design. Maximum board thickness is PCB thickness excluding copper plating, solder

or solder mask. Aspect affects the difficulty of plating. The larger the aspect ratio, the more difficult it is

Electroplating process will be.

We please can build the board with the aspect ratio listed in Table 10 below:

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Table 10

Minimum plated hole size Available aspect ratio Maximum board thickness available

0,15 mm

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At Bittele Electronics, we typically add drop pads whenever possible when an annular ring is thinner than 7 mils

as it increases tolerance limits for errors and reduces the likelihood of later PCB problems

Manufacturing and assembling.

Whether tear pads are needed or not depends on the ring thickness of the plated holes:

For ring rings < 7mil, tear pads are recommended but not required

No tear pads are required for the annular ring >= 7mil

4.7 Lochabstand

Distance means the distance between two features. Usually there is a slight misalignment between different ones

Copper layers and we will locate holes according to the fiducials we will add on the countertops.

So if the spacing between the hole and other copper features is too close, the holes may be drilled too narrow

to the copper features due to misalignment, and eventually this can cause a short circuit or damaged pads.

The higher the number of layers, the bigger the misalignment could be and the bigger the spacing we need.

The distance to be designed between the holes to other copper elements depends on the number of layers as shown

below in Table 12:

Table 12

Number of layers Minimum distance between the hole and other copper elements

=10 12.0 mil preferred (minimum 8.0 mil)

4.8 Ladder Clearance

Conductor spacing is the distance between traces or other copper elements. Sufficient freedom from traces is

important to ensure that manufacturing tolerances do not affect the function of your board. In addition to

To ensure that the ladder width matches the gerber, we need to compensate (or increase) the ladder in gerber.

to counteract the effect of undercutting, as discussed in Section 4.2 Etch Factor. The heavier the copper weight is,

the deeper the etch, the wider the conductor spacing to compensate. Minimum conductor spacing depends on copper weight as shown in Table 13 below.

Table 13

Copper Weight Minimum Spacing (Inner Layers) Minimum Spacing (Outer Layers)

0.5 oz 4.0 mil preferred (3.0 mil minimum) 4.0 mil preferred (3.0 mil OK only in a few places)

1 oz 5.0 mil preferred (4.0 mil minimum) 6.0 mil preferred (5.0 mil minimum)

2 oz 7.0 mil preferred (6.0 mil minimum) 8.0 mil preferred (7.0 mil minimum)

3oz 10.0mil preferred (minimum 9.0mil) 12.0mil preferred (minimum 10.0mil)

>3oz Ask our sales team for a review. Ask our sales team for a review

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4.9 Treatment of via holes

The plating thickness in vias is determined by the parameters when copper plating is performed for the board.

Our copper plating can range from 20m to 30m. If you need a thicker via, it will affect the copper

Weight on the top and bottom layers, because the thicker the plating for the through holes, the thicker the top and bottom

Layers are plated. If you are concerned about heat conduction, we do not recommend using the through holes

conductive epoxy, and then plate over it using the "via in pad" process. There is a cost to this process, but it is

less and more reliable than filling the hole with conductor.

The solder mask opening (also called solder mask clearance) indicates the area that should not be covered

solder mask oil. These openings must be on their own separate layer in the Gerber files for each exterior

side of your board. For the via holes in your boards Gerberfiles if you haven't designed a soldermask opening

For them we can treat them as described in Table 14.

Table 14

Via Hole Treatment Boundary Condition Additional Cost

Clogged with solder resist 1. The hole diameter must be less than 0.5mm; 2. No solder mask opening on both sides; 3. The thickness of the finished board should be 0.5mm-2.4mm.

NO

Covered with solder mask N/A No

Via-in-Pad 1. The hole diameter must be less than 0.6mm; 2. Finished board thickness is greater than 0.5mm~2.4mm. 3. The material cannot be PTFE material.

And

Stuffed with solder mask: The holes are first built like normal through holes and then filled with solder

mask oil. Once plugged in, no light can penetrate through the holes. If you are using a part with a BGA

Package, we suggest you plug the through holes under the BGA area to avoid short circuit when assembling.

Covered with Solder Mask: Solder mask oil covers the top of the through hole copper pads and solders

Mask oil can also flow into the holes, but the holes are not filled, and light can pass through these holes.

Via-in-Pad: The via holes are filled with non-conductive epoxy and then plated over. while there is

For some via holes designed on SMD pad, we may also need to build via-in-pad to avoid the risk

leaking tin when assembling certain designs.

4.10 Finished panel thickness

The total finished board thickness can be measured from a PCB top surface to its bottom layer including the solder

mask and copper layers. This dimension is used to design enclosures for the board. Don't forget the bill

for component height in your overall design. The maximum panel thickness is as shown in Table 15 below.

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Table 15

Number of plies Maximum panel thickness (inches) Maximum panel thickness (mm)

2 layers 0.149 preferred (0.236 possible) 3.8 preferred (6.0 mm possible)

Note: For 2-layer boards, if the board is thicker than 3.0mm, we may need to build it as a dummy 4-layer board, as we don't have a suitable substrate for that thickness.

4.11 Total tolerance of finished profile

A surface profile is a three-dimensional tolerance zone outline around a surface plane that is defined through the use of base radii

Dimensions, coordinate dimensions, angular dimensions. The profile tolerance is a uniform limit around a

Board surface where there are elements of the surface created by offsetting each point forming two

tolerance zones. Profile tolerances control a feature's shape, size, orientation, and sometimes position

with profile elements being curved lines, straight lines and surfaces.

At Bittele, we can manufacture a PCB to the tolerances listed in Table 16.

Table 16

Imperial metric

Hole to board edge 6 mil preferred (min. 4 mil) 0.15 mm preferred (min. 0.1 mm)

Board edge to board edge 6 mil preferred (min. 4 mil) 0.15 mm preferred (min. 0.1 mm)

V-Score to V-Score 6 mil preferred (min. 4 mil) 0.15 mm preferred (min. 0.1 mm)

4.12 Board Outline

As part of the Gerber files of your designs, we need an outline of the final shape of your board. This way you can

Check your end result and make sure the conductors and components are a safe distance from the edge. We at

Pleasele requires a clearance of 0.2mm (8 mil) for standard cuts and 0.4mm (16 mil) for V-edges, in between

Your copper and PCB edge to accommodate manufacturing tolerances. If possible, a larger distance is preferred.

Edge connectors do not require this spacing. We are able to cut complex shapes to your board

additional costs. Our minimum cutter size is 0.8mm, so all cutouts must be larger or they can

be a slot hole. Our outer panel tolerance is +/-0.15mm.

4.13 Edge Bevel

Edge chamfering is the process of creating a transitional edge between two faces of a circuit board that is normally performed

the outer edge of the board. Beveling is commonly used on edge connectors to allow for smoother insertion

another circuit board socket. The edge connector pins are often called gold fingers because they are plated in

Gold and there are several of them grouped together in parallel. Goldfingers are discussed further in section

6.7 Edge connector coating. For Goldfinger we at Bittele have the options listed below:

Available chamfering angles: 20, 30, 45 and 60 degrees

Residual thickness after chamfering: >=0.3mm (0.2mm is ok but ask for a quote)

You can calculate the depth or residual thickness of the chamfer using the geometry shown in Figure 6 below.

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Figure 6: Edge bevel of Goldfinger profile view

= 2 sin

where d is the depth, a is the bevel angle, t is the panel thickness and tris is the remaining thickness.

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5.0 Possibilities of HDI technology In addition to the standard circuit board, we at Bittele can also produce HDI circuit boards (with laser holes, blind holes or buried

holes, etc.). And for such boards, we can build them with even smaller trace space. Our ability is

specified in this section.

What are HDI boards? High Density Interconnect (HDI) technology is used in the wiring network of multilayer printed circuit board manufacturing

to connect different PCB layers together. Bitteles manufacturing facility maintains various limits or tolerances

which are recommended for HDI PCB manufacturing to avoid problems with your manufactured PCB. Different

Types of micro vias like blind vias and buried vias in the different layers are used to make these complex HDI

circuit boards.

5.1 Narrow track width / space

The circuit board traces are a continuous path of copper along which electricity flows. The release

Clearance on a PCB design refers to the space or gap used to separate traces from other elements on the copper

Layer. We must maintain a minimum clearance for each trace width to avoid and allow for short circuits

for manufacturing tolerances. The trace width and the minimum distance depend on the copper

Weight of the inner and outer layers on the board. For our ability of trace width and space on HDI boards,

see Table 17 below.

Table 17

track width / free space

Internal layer 1/2 OZ: 3.0/4.0 mil (preferred) 3.0/3.0 mil (minimum)

1 OZ: 4.0/5.0 mil (preferred) 3.0/4.0 mil (minimum)

2 OZ: 5.0/7.0 mil (preferred) 4.0/5.5 mil (minimum)

3 OZ: 6.0/10.0 mil (preferred) 5.0/8.0 mil (minimum)

External layer 1/2 OZ: 4.0/4.0 mil (preferred) 3.0/4.0 mil (minimum)

1 OZ: 4.0/6.0 mil (preferred) 4.0/4.0 mil (minimum)

2 OZ: 5.0/8.0 mil (preferred) 5.0/6.0 mil (minimum)

3 OZ: 6.0/10.0 mil (preferred) 6.0/8.0 mil (minimum)

5.2 BGA

BGA is short for Ball Grid Array, a form of surface mount technology (SMT). BGA is now more chosen

common in circuit design. BGA packages have been developed due to market demand for more rugged and

convenient housing for permanent mounting of integrated circuits with a large number of pins. BGA enables more

Connection pins per face than possible with a dual in-line or flat pack. Some BGA components

Even assemble integrated circuits with over 100 pins. To achieve this, the entire bottom of a BGA chip is large

filled with connecting pins. By not limiting connections to the perimeter, connections below the SMD

Package will increase the efficiency of space use.

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Over the years, Bittele Electronics has accumulated tremendous know-how in assembling Ball Grid Arrays (BGA).

and has developed a reliable process over time. Currently, our manufacturing and assembly facilities use the

state of the art BGA pick and place equipment and we also use x-ray inspection equipment to verify this

Soldering. We have a proven track record of manufacturing BGA PCBs with excellent yield rates and the highest

Quality in electronics manufacturing. At Bittele we can also process BGA packages

Specifications listed in Table 18.

Our skilled staff also use thermal profiles for low volume prototype boards as this is a key feature in

BGA assembly process. We carefully review the PCB files and BGA chip datasheets to create the

the most suitable thermal profile for BGA assembly. Lead-free BGA circuit boards go through a special process

Lead-free thermal profile to avoid ball problems that can occur due to using a lower temperature.

Alternatively, the expensive leaded BGA boards are rerouted through special leaded processes to avoid high

Temperatures that cause pin shorts. We have effective quality control procedures in place to provide the highest level of quality

quality service.

We have high-tech BGA pick and place equipment, precise BGA assembly processes and automated X-ray

Inspection system (AXI) to ensure better quality of BGA PCB assembly. AXI is used to identify the assembly

Defects; Our team uses 2D X-rays to render 3D images to verify issues like broken vias on the PCB

in inner layers and BGA balls cold solder crack.

Table 18

capability of the BGA package

Size available 2mm x 3mm ~ 45mm x 45mm

Available material ceramic, plastic

Available clearance At least 0.4mm (0.35mm is fine, but an estimate is needed.)

5.3 Mikro-Via

Standard micro vias are made up of tiny copper plated holes 6 mil (0.15 mm) or less in diameter and are manufactured

with a laser drill. Micro-vias can connect adjacent layers, allowing a single multi-layer PCB to accommodate more circuitry

traces, which increases PCB circuit density. Although a single standard micro via can only connect two adjacent ones

copper layers there is still significantly more space available for conductor tracks. Microvias consisting of various

Types such as blind via and buried via are used in HDI (High Density Interconnect) PCB designs.

A standard micro via is a highly reliable type of connection structure and should be used in a circuit board design

if possible. For an HDI PCB, the circuit paths must connect multiple layers to connect components

but a standard micro-via can only be used to connect two adjacent layers. So to use Micro-Via in

In HDI board design, we need to use the micro vias in a compound design structure to connect more than two

neighboring layers. There are two types of complex structures that use a standard micro-via: staggered and

stacked structures. These structures are described below in Sections 5.3.3 and 5.3.4.

At Bittele Electronics, we can manufacture microvias from 4 mil (0.1 mm) in size up to a maximum size

of 6 mils (0.15mm). Manufacturing these vias requires separate drill files with the via locations on each

the different layers of a multilayer circuit board. An HDI circuit board layer with buried and blind vias can be laminated

maximum three times on the same page. This means that a maximum of 3 can be processed on board

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Steps for blind or buried vias. For example, when building boards from the center, we can have a buried via

a middle layer, then a second process can add layers on either side with more buried vias, and then a third

Pressing can add blind vias to the outer layers. Finally, through holes can be drilled for a total of 4 drilling stages.

See Figure 7 below for an example.

Figure 7: Example of a 10-layer HDI board with maximum viasteps

5.3.1 Blind Via A blind via is a copper-plated hole on a HDIPCB that can connect one of the external layers to one or more

inner layers passing through two or more inner layers. Blindvia is only visible on one side of the board

since it can only connect an outer layer with inner layers. However, a blind via connection cannot happen

The entire board is directly connected to the other outer layer, although it must be connected to one of the outer ones

The law.

5.3.2 Buried Via A buried via is a copper-plated hole that connects two or more inner layers, but does not connect to an outer layer

Layer. A buried via is hidden inside or inside the board so that it is invisible from the outside as it is buried

Via can only pass between the inner layers. Buried vias are only used to connect the various inner layers along the way

no connection to an outer layer. The drilling must therefore be done before the circuit board is pressed. For

1+n+1, 2+n+2, or 3+n+3, n represents a buried via core layer on this multilayer board and die

Numbers represent the pairs of laser holes over the core layer. Also laser holes on these inner layers can

be plated closed with copper.

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Figure 8: Representation of via types

5.3.3 Stacked Micro-Via Stacked micro-via is a kind of composite design structure in which micro-vias are stacked on top of each other

Micro vias are space efficient, allowing you to achieve the highest circuit density possible, and are easier to use

as a tiered structure. Unfortunately, stacked micro vias are less reliable the larger the via experience

thermal stress during the reflow soldering step. Consequently, they are considered even less reliable than a

through-over.

5.3.4 Staggered Micro-Via Staggered micro-via is a type of composite design where micro-vias are placed with small offsets from each other

between layers. This is the most reliable complex design structure, but it requires a little more space in the HDI

PCB-Design.

5.4 Multiple Laminations/Sequential Lamination

Lamination is a technique for making a composite material with multiple layers, in this case a multilayer

circuit board. Laminating sheet materials into a multilayer PCB involves fusing two or more different laminate sheets together

by heat, pressure, welding or adhesives. There are many different methods of laminating and a variety of

PCB material allows multiple lamination processes to be applied to PCB design.

For non-HDI panels, a single lamination step fuses all layers

multilayer PCB is sequential lamination; a process that begins on a core layer that is fused to a conductive and a dielectric

Layer on both sides with multiple printing passes. Sequential lamination allows for both blind and buried vias

created during the build process, allowing discrete or molded components to be embedded using High

Density Interconnect (HDI) technology for the manufacture of HDI printed circuit boards. Due to the complexity of the sequential

lamination process, it may add significant cost to plate making and increase lead time. Please

Electronics recommends consulting with one of our representatives if your HDI PCB design requires it

constructed by sequential lamination. Although BitteleElectronics has the ability to manufacture in multiple layers

For circuit boards with up to 40 layers, it is advisable to construct your circuit boards with a maximum of 20 layers. A PCB layer called

a core, copper and prepreg layer in a PCB without screen printing, solder mask and other layers.

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6.0 Surface Finish: Options and Requirements The application of surface finish is one of the most important but least understood steps in the manufacture of printed circuit boards. surface

Lacquers are used to cover and protect the solder pads of a circuit board. As a PCB designer, it is important to understand

the different finishes available to you and the pros and cons of each.

The finish acts as a protective coating to shield copper that is not covered by a solder mask on a printed circuit board

circuit board (PCB). A surface finish can be applied to a circuit board by one of three main methods: dipping, dipping or

electrolytic fusion. Dipping involves lowering and dipping parts of an unfinished circuit board into a vat of liquid metal

Surface finish while being limited to just covering desired areas with surface finish. Immersion is a method

In this process, a circuit board is completely immersed in a bath of liquid metal surface finish, which completely galvanizes the circuit board. Last,

In the electrolytic plating process, the circuit board is immersed in a solution containing dissolved metal ions known as

an electrolyte. An electric current is then passed through this solution so that metal ions are deposited

on the conductive surface of the circuit board. There are many different types of surface finishes that we at Bittele offer

a variety of the most popular styles available as options in our PCB fabrication services.

6.1 HASL/LF-HASL

Hot Air Solder Leveling (HASL) is the most common type of PCB

Surface finishing used in industry. HASL surfaces are composite

Solder, with shares of approx. 63% tin and 37%

Lead, commonly referred to as a 60/40 split. The process for

Applying this finish begins with dipping the PCB in a

Tin/lead alloy crucible after solder mask

applied. Next, a Hot Air Leveler (HAL) removes the excess solder,

with hot air knives to leave only the thinnest possible

Layer. This remaining layer of solder protects the conductor tracks

Underneath from corrosion while facilitating the task of soldering

Components on the board by pre-tinning the entire pad. HASLis

a very inexpensive surface finish compared to other types of

surfaces and is therefore considered a good choice for general

purpose boards.

Lead-Free Hot Air Solder Leveling (LF-HASL) is similar to HASLin

appearance and use; however, in this case the solder contains a mixture of 99.3% tin and 0.6% copper. The

Alloying results in a higher melting point for lead-free solder compared to leaded solder. LF-HASL is on

Replacement for leaded solder, used when a lead-free or RoHS compliant PCB is required. Please note that a

Higher temperature tolerance laminate is needed to apply this finish; Otherwise the process

identical.

Historically, HASL has been one of the most popular surface options due to its cheap and robust qualities

Solution. Recent fundamental changes in the PCB industry, such as B. New, more complex surface mount

technology (SMT), have revealed the shortcomings of HASL. HASL is not suitable for use with SMT due to bumps

Surfaces incompatible with fine-pitch components. Recently, lead-free LF-HASL became available, but

Now there are other lead-free options that are better suited for a highly reliable product.

Figure 9: Example of a HASL surface texture

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Advantages

Low-Cost-Finish

Widespread

Repairable layer

Outstanding durability

Disadvantages

uneven surfaces

Not good for fine pitch components

thermal shock

Not good for plated through holes (PTH)

Poor wetting

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solder bridges

May contain lead (HASL)

Bittele offers a variety of surface finishing options, all at a standard price, including HASL. Please note beforehand

Order that standard HASL finishes contain lead, therefore boards with this finish are not RoHS compliant

norms. We recommend planning for the LF-HASL option if you want this type of finish.

6.2 ENTEK/OSP Organic Surface Protectant (OSP) is a type of water

based, organic surface finish that is typically applied

Copper pads on a circuit board. OSP is an organic chemical

compound that binds selectively to copper pads, and

provides an organometallic layer to protect this copper

Layer. However, OSP is not as robust as HASL and is very robust

sensitive to small abrasions, which must be avoided with gloves

Scratch. OSP is an environmentally friendly compound,

and extremely green compared to other lead-free

Paints that typically contain more toxic substances or

require significantly higher energy consumption. OSP is

a good lead-free finish, with very flat surfaces though

it has a very short shelf life. To apply this surface finish,

All you have to do is immerse the circuit board in a chemical bath

OSP connection, but one must note that this can only be

done after all other processes are complete, including

Electrical testing and inspection. OSP is not a standard

surface finish and incurs additional costs if selected.

Advantages

Bleifrei

level surface

Simple process

Repairable

cost efficient

Disadvantages

Not good for PTH (Plated Through Holes)

No way to measure thickness

Short shelf life

May cause ICT problems

Exposed Cu in final assembly

Handling Sensitive

Figure 10: Example of an OSP surface texture

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6.3 AGREE

Electroless Nickel/Immersion Gold (ENIG) is a double layer

metallic surface refinement consisting of a very thin layer

of gold applied over a layer of nic