1. April 4th , 2016 Seo, Dong-yoon SKKU EMC Laboratory
Introduction of PCB
April 4th , 2016
Seo, Dong-yoon
SKKU EMC Laboratory

2. Agenda Intro PCB Type PCB Material PCB Structure
Cu foil, PPG, CCL, PSR
PCB Structure
PCB Stack-up, PCB Hole
PCB Manufacture Process
Process, Key parameter
PCB Specification
Q & A

3. Intro
PCB History
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4. Intro PCB ? Printed Circuit Board Purpose Application
Complicated Circuit’s Transmission Line  Microstrip or Stripline
Simplify, High Integration, High Efficiency, Small form factor, …
Application
Nearly every electronic device
Examples
PKG Substrate PCB
Intel Server Main Board PCB
Samsung DDR3 SODIMM
(designed by DY.SEO)
iPhone6 PCB
iPhone5s PCB

5. PCB Type General Criteria of PCB type
Number of Layer / Flexibility / Material of PCB.
Embedded PCB Technology will be involved additionally.
Layer
Single Side PCB
Double Side PCB
Multi Layer PCB
Flexibility
Rigid PCB
Flexible PCB
Rigid-Flexible PCB
Material
Epoxy PCB
Teflon* PCB
Polyimide PCB
B.T PCB
Metal core PCB
- Main
- Glass fiber + Resin
- High frequency
- High cost
- Good Flexibility
- Bismaleimide/
Triazine
- Good Heat Radiation
- Al + Tpreg + Cu
* Teflon은 불소와 탄소의 강력한 화학적 결합으로 인해 매우 안정된 화합물을 형성
Multi Layer PCB
Rigid-Flexible PCB

6. PCB Material (1/4) Copper foil PPG (Pre-preg)
Signal pattern, power plane, SMD pad
Unit of Copper foil thickness = Ounce (?)
1oz : g / 1ft x 1ft = 305g /1M×1M = 35㎛
PPG (Pre-preg)
Thermosetting resin + Glass fiber (and so on)  SHEET of B STAGE (B STAGE : semi hardening state of resin)
Type of PPG (1)
Glass fiber
Type
Resin
Contents
Glass size
Number of
Fiber / inch2
Thickness after Press
1080
 62 ± 2 % 
50.8 ㎛ 
 60 X 47  
60 ~ 70 ㎛
 2116
 52 ± 2 % 
101.6 ㎛ 
 60 X 58 
110 ~ 120 ㎛
 7628
 42 ± 2 % 
170.1 ㎛ 
 42 X 32  
180 ~ 190 ㎛ 

7. PCB Material (2/4) PPG Type of PPG (2) Main Volume : FR-4
Data sheet of FR-4 (DS-7402 Halogen Free)
Resin
Stiffness material
Description
FR-2
Phenol
Paper
≒ FR-1
FR-3
Epoxy
FR-4
Glass fiber
Tg 125~135°C
FR-5
Hi Tg 150~160°C
CEM-1
≒ FR-1 (Less smell)
CEM-3
Non-woven glass fiber
≒ FR-4 (Low cost)
Glass transition temperature
Coefficient of Thermal Expansion
Global Er
= Glass fiber + Resin
* Er Example
Glass fiber Er : 6.2
Resin Er : 3.6
Source :

8. PCB Material (3/4) CCL Copper Clad Laminate
Copper foil + Prepreg + Copper foil
Panel design is important to improve the PCB productivity.
1860nm
Treated side
407nm
Shiny side
Laminate with Copper Foil

9. PCB Material (4/4) PSR (or Soldermask) Photo imageable Solider Resist
Purpose
Protect the outer layer copper (signal pattern and power plane).
Form the SMD/NSMD pad
SMD (Solder Mask Defined Pads)
NSMD (Non-Solder Mask Defined Pads)
PSR ink type
Screen type
Coating goes well and because developing solution uses alkali aqueous solution, problem of environmental pollution is less and is excellent. It is suitable for various kinds Finish Treatment (HASL, ENIG, Tin Plate, OSP, etc).
Spray type
Good Productivity, Uniform coating thickness.
Pad definition
Various color of PSR
Source :

10. PCB Structure (1/2) PCB Stack up
(IPC 6012) Board Type Printed boards without plated-through holes Type 1 and with plated-through holes Types 2-6 are classified as follows:
Type 1—Single-Sided Board
Type 2—Double-Sided Board
Type 3—Multilayer board without blind or buried vias
Type 4—Multilayer board with blind and/or buried vias
Type 5—Multilayer metal core board without blind or buried vias
Type 6—Multilayer metal core board with blind and/or buried vias
Configuration of multi layer PCB
Example for 6-Layer
Preferred Method
3 CCL + 2 PPG + 0 Cu foil
2 CCL + 3 PPG + 2 Cu foil
Source :

11. None Plated Through Hole
PCB Structure (2/2)
PCB Holes
Purpose
Interconnect layers  Via
Mechanical support for PCB manufacturing or SMT Assembly  Tooling hole
Cu Plating difference : Plated vs None plated
Drilling method : Mechanical hole vs LASER hole
Interconnection method : Full layer vs Partial layer
Term
ACRONYM
None Plated Through Hole
NPTH
Plated Through Hole
PTH
Interstitial Via Hole
IVH
Blind Via Hole
BVH
Buried Via Hole
(BVH)
LASER Via Hole
LVH
Stacked Via -
Staggered Via
Skipped Via
Staggered
Via
Stacked
Skipped
IVH

12. PCB Manufacture Process (1/3)
Process for Multi layer
General process
Step 10 (DF striper) and 11 (Etching) are swapped at below table.
Step 12 (PSR) has DRY FILM process for PSR patterning like copper etching process.
Step 14 is surface finish process.
ENIG / OSP / HSAL / EPENIG …
Source :

13. PCB Manufacture Process (2/3)
Key Parameter
Aspect ratio
Aspect ratio is the ratio between the thickness of the board and the size of the drilled hole before plating.
According to the aspect ratio, the plating method will be changed.
Term
DC Plating
Reverse Pulse Plating
Hole height (PCB Thickness)
~ 2.0mm
~ 8.4mm
Drilled hole size
0.2 ~ 0.35mm
0.2 ~ 0.3mm
Aspect ratio
~ 8
6 ~ 20
Plating method

14. PCB Manufacture Process (3/3)
Key Parameter
Etching Copper
Etching factor is the ratio between the Cu thickness (V) and side attack of Cu (X).
Higher is better.
Throwing Electroplating
Throwing power is a measure of an electroplating solution's ability to plate to a uniform thickness over an irregularly shaped cathode.
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15. PCB Specification (1/2)
IPC (The Institute for Interconnecting and Packaging Electronics Circuits)
The industry association for printed circuit board and electronics manufacturing service companies, their customers and suppliers
ROHS(Restriction of Hazardous Substances)
Do not use ‘Lead, cadmium, mercury, chromium’.
* 전기전자제품 유해물질 사용제한 지침
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16. * 소비용품의 안정성을 확보 및 소비자를 보호하기 위해 운영하는 인증제도
PCB Specification (2/2)
UL (Underwriters Laboratories Inc)
Leading product safety testing and verification organization in US.
UL certifies, validates, tests, verifies, inspects, audits, advises and educates.
FLAMMABILITY STANDARD (Ex. SAMSUNG Memory module 94V-0)
* 소비용품의 안정성을 확보 및 소비자를 보호하기 위해 운영하는 인증제도
You can see this logo at PCB
UL Logo
Source :