IPC Part: 3Base Material

for Printed Circuit Boards

A PWB is born and develops into an unruly teenager.

Product spec

Component data

Electronic scheme

Net listBOM

IPC-2141AIPC-2251

IPC-7093

J-STD-609AIPC-1752AIPC-2610

IPC-7094

Footprints

Component placement

Routing

IPC-2222AIPC-7351BIPC-7095CIPC-7525B

IPC-2221B

Program for:-Laser Plotter-Drilling-Routing-AOI-Electric test

IPC-2581

To Bare Board

Production

Gerber filesDrill filesBare BoardSpec

IPC-2152

IPC-7527

FR4FR4

High Tg

FR4 BFR Free

?FR4 IL

IPC-4101D

IPC-4562A IPC-4121IPC-4563

DATA from CAM

IPC-9691A

Please fill in!!

IPC StandardsBase Material Standards.• IPC-4101D Rigid Boards.• IPC-9691A CAF.• IPC-4562A Metal Foil for Board Applications.• IPC-4563 RCC Foil for Board Guideline.• IPC-4121 Guideline for Selecting Core

Construction for Multilayer Applications.

IPC-4101DMaterial Composition Keywords All Appropriate Specification SheetsBT / Epoxy / Woven Glass 30

Cyanate Ester / Woven Aramid 54

Cyanate Ester / Woven Glass 71

Cyanate Ester / Woven S-2 Glass 70

Cyanate Ester / Woven Quartz 61

Epoxy / Cyanate Ester / Woven Glass 29

Epoxy / Non-Epoxy / Nonwoven Aramid 58

Epoxy / Non-Epoxy / Nonwoven Glass 28

Epoxy / Nonwoven Aramid 55

Epoxy / Paper 04

Epoxy / PPO / Woven Glass 25, 103

Epoxy / Woven Aramid 50

Epoxy / Woven Glass 20, 21, 22, 23, 24, 26, 27, 82, 83, 92, 93, 94, 95, 97, 98, 99, 101, 121, 122, 124, 125, 126, 127, 128, 129, 130, 131

IPC-4101DMaterial Composition Keywords All Appropriate Specification SheetsEpoxy / Woven Glass / Nonwoven Glass 12, 16, 81

Epoxy / Woven Glass / Paper 10, 15, 80

Phenolic / Paper 00, 01, 02, 03, 05

Polyester / Glass 13

Polyester / Woven Glass / Nonwoven Glass

11

Polyimide / Epoxy / Woven Glass 42

Polyimide / Nonwoven Aramid 53

Polyimide / Woven Glass 40, 41

Polyimide / Woven Quartz 60

PPE / Woven Glass 90, 91, 96, 102

IPC-4101DDescription or Application

KeywordsAll Appropriate Specification Sheets

Additive / Semi-Additive 80, 81, 82, 83

Composite 10, 11, 12, 14, 15, 16

Consumer Electronics 00, 01, 02, 03, 04, 05, 10, 11, 12, 14, 15, 16, 80, 81, 82, 83

Crossplield Unidirectional 27, 54

Double-Sided 12, 14, 16, 81

Heatsink Application 31, 32, 33

Lead-Free FR-4 99, 101, 121,122, 124, 125, 126, 127, 128, 129, 130, 131

Lead-Free Non-FR-4 16, 102, 103

Microvia 53, 55, 58

RoHS

IPC-4101DANSI or Military Keywords All Appropriate Specification SheetsCEM-1 10, 15, 80

CEM-3 12, 14, 16, 81

CRM-5 11

FR-1 02

FR-2 03, 05

FR-3 04

FR-4 21, 24, 26, 27, 82, 83, 92, 93, 94, 95, 97, 98

FR-5 23

G-10 20

G-11 22

XPC 00

XXXPC 01

GFN 21

GFT 26, 28

GPY 30, 40, 41, 42

IPC-4101DMaterial Property Keywords All Appropriate Specification SheetsCAF Resistance 29, 30, 61, 70, 71, 102, 126, 129, 130, 131

High Td (Decomposition Temp) 99, 124, 125, 126, 128, 129, 130, 131

High Reliability 40, 41, 42

Hot Flex Strength 22, 23

Low Dk / Df 13, 25, 50, 53, 54, 55, 58, 61, 70, 71, 90, 91, 96, 102, 103

Low Halogen Content 05, 14, 15, 58, 92, 93, 94, 95, 96, 122, 125, 127, 128, 130, 131

Low X / Y CTE 50, 53, 54, 55, 58, 60, 61, 70

Low Z-axis CTE 99, 101, 102, 121, 122, 124, 125, 126, 127, 128 129, 130, 131

Non-Flame Retardant 20, 22

Thermally Conductive 31, 32, 33

RoHS

RoHS

RoHS

IPC-4101DMaterial Modifier Keywords All Appropriate Specification SheetsFillers 10, 11, 12, 13, 14, 15, 16, 31, 32, 33, 40, 41, 42,

80, 81, 82, 83, 97, 98, 99, 101, 102, 103, 126, 127, 128, 130

Multifunctional Epoxy 24, 55, 83, 94, 95, 98

RoHS

Early & New Curing Agents• Dicy

– Dicyandiamide.– Cure system for epoxy launched in 1970s.– Replaced ”Novolac” Phenolic cure system .

• The reason was that ”Novolac” miss colored the laminate.

– Used in standard FR-4 base material.

Early & New Curing Agents • Non-Dicy

– The “old” Phenolic (Novolac) cure system.– Reintroduced due to RoHS!– Improves the Thermomechanical parameters for

the laminate: • Higher Tg and Td. • Lower Overall CTE.

– Used in FR-4 base material suitable for Lead Free processes.

RoHS

Early & New Curing Agents• Filler

– Talc [Mg3Si2O10(OH)2]• But can be something else; often proprietary

– Fillers more heavily used due to RoHS!– Improves the Thermomechanical parameters for the

laminate:• Lower overall CTE• Higher Td

– Used in FR-4 base material suitable for Lead Free processes. RoHS

IPC-4101DSpecification for Base Material• Cupper foil thickness. • Thickness tolerances.• Overview Tables.• Specification Sheets for Base Laminates

(66 separate base Materials)

IPC-4101D

Important Parameters for Base Materials

• Tg = Glass transition temperature• Td = Degradation temperature

• T260 = Time to delaminating at 260˚ C

• T288 = Time to delaminating at 288˚ C

• CTE = Coefficient of Thermal Expansion

Tg = Glass Transition Temperature

Movie_02.wmv

24

Glass Transition Temperature Tg ( PCB Laminates)

50˚C

100˚C

150˚C

200˚C

250˚C

300˚C

0˚C

Expans

Ion

P/

P

M

Glass Epoxy Laminate FR4

Tg ~125˚C

280 ppm

< 60 ppm

a1

Z-axis Expansion

Effects of Entrapped Moisture in PCB !!!

a1

TgTg

Tg Reduction from 10 to 30°C depending on PCB material, fabric,Cu %

Warping of PCB and Substrate of P-BGA

Z

25

Since moisture acts as a plasticizer, it reduces the Glass Transition Temperature Tg (- 10 to 30°C), effects on CTEz, which in turn increases stresses on PCB features such as Plated Tthrough-Holes (PTH), and the same for P-BGA substrate (ie. FR4, BT), etc..

PCB Moisture Absorption – Additional issue

Room Temperature

Expansion After Tg

CTE = Coefficient of Thermal Expansion

RoHS

Temp over Tg gives high CTE

CTE Cu = 15 ppm/ºC

CTE FR-4 in z-axis 50-60 ppm/ºC under Tg

CTE FR-4 in z-axis 250-300 ppm/ºC over Tg

SAMPLE A

Influence of CTE

How many PTH do you have in your PCB?

What is the consequence of the Base material in the Reflow process?

What is the Result?

FR4FR4

High Tg

FR4 BFR Free

?FR4 IL

IPC-4101D

IPC-4562A IPC-4121IPC-4563

DATA from CAM

IPC-9691A

CAFConductive Anodic Filament

38

How does it look like in the real world?

Regarding CAF

CAF – Example

Conductive Anodic Filament =

Electrochemical reaction between copper anode and cathode

Formation of copper filaments (Electro migration)

RoHS?

Glass fabrics

Resin

Cu Cu

Bonding zone

Glass fabrics

Resin

Cu Cu

Bonding zone

Humidity is absorbed in the PCB

After some time a humidity layer is formed by time

42

PTH - PTV Walls

Moisture (H2O) and Ionic Impurities - pH

CAF

Anode (+) Cathode (-)

Cu CuFabric Fiber Glass plus Resin

Power DC

H2O

Conductive Anodic Filament CAF

H+ions OH- ions

Bad Drilling, Bad Hole Metallization, PTH Voids, Laminate Blistering, ecc, together with Moisture and DC Power, easy to have CAF Formation

Cu salts

43

Cu Cu

Anode (+) Catode (-)

Fiber Glass CAF

H2O Moisture

DC Power

H+ions OH- ions

CAF Formation and Growing Mechanism

Epoxy resin

Cu salts

44

CAF

+ 20 Volt Power Plane

Component Through Hole

A SEM micrograph illustrating the type of catastrophic failure that can be caused by CAF

45

• Interfacial degradation resin-fiber glass (and

moisture).can result in a reduced Time To Failure (TTF) due to ..Conductive Anodic Filament Formation (CFF) (CAF).

• Demand for laminate and PCB material CAF Resistant is Growing as the Lead Free and HDI Technology has an increased market .

PCB Moisture AbsorptionMoisture can cause :

IPCUser Guide for the

IPC-TM-650• IPC-9691A

– 2.6.25 Conductive Anodic Filament (CAF) Resistance Test (Electrochemical Migration Testing)

FR4FR4

High Tg

FR4 BFR Free

?FR4 IL

IPC-4101D

IPC-4562A IPC-4121IPC-4563

DATA from CAM

IPC-9691A

Practical Advice

You need anIPC Checklist!!