Practical guidelines for

PWB Moisture Sensitivity,

Packaging and Handling

Mumtaz Y. Bora

Peregrine Semiconductor

San Diego, CA, USA

Agenda and Overview

Industry Standards for Moisture Sensitivity Packages

Package Handling/Baking/Packaging Guidelines

PWB Handling/ Baking/Packaging Guidelines

Controls at PWB/Assembly Site

Summary

Moisture Classification Level and Floor Life

Level Floor life (out of bag) at factory ambient <30°C/60% RH or as stated

1 Unlimited at <30° C/85% RH

2 1 year

2a 4 weeks

3 168 hours

4 72 hours

5 48 hours

5a 24 hours

6 Mandatory bake before use. After bake, must be reflowed within the time limit specified on the label

Handling PWB Moisture Sensitivity

J-STD 020E -03/2008- IC Package MSL Class

J-STD 033C –01/2007 –Assembly MSL –Floor Life

J-STD –075 –Non-IC Packages for Assembly

IPC –HDBK-001 -Baking Guidelines

IPC TM 650 –2.4.24.1 –Time to Delamination

IPC TM 650 2.3.40 Decomposition Temperature

IPC SM 840D Solder Mask Qualification

IPC 4101B -Laminate and Pre preg Materials

J-STD-609 – Marking and labeling of Components, PCBs and PCBAs to Identify Lead ,Lead Free and other Attributes

IPC 1601A– Printed Board Handling and Storage guidelines- Contact :Joseph Kane – BAE systems- IPC liaison- John Perry /Nancy Jaster

PWB Moisture Uptake

Resin System

Type of PWB construction

Environment

Temperature

Humidity

Rinse Operations

Storage/Handling

“Moisture Sensitivity is not driven by Material alone”

Industry Guidelines for Maximum Moisture Content before packaging PWBs

Test Method- TM 2.6.28 PWB Maximum Moisture Content Measurement

PWBs Used for Lead Free Reflow

Mid Tg- 150C – 310C Td

High Tg -170C –340C Td

Halogen Free Laminates -170C – 340C Td

Proposed Guidelines IPC- 1601Rev A

Max Moisture – 0.1% for Lead free Reflow (260C Max).

Max Moisture - 0.2 % for Lead based Reflow (230C)

Test Method – IPC TM-650 Method 2.6.28

Typical Delamination Defects

Delamination

Blistering

PWB Supplier Quality Controls

Storage/Handling Controls

Prepreg Storage

Laminate Storage

Inner Layer Production

Etched Cores

Sub-Assembly

Laminated Panels

Evaluate/Audit :

Transportation of Product

Environment (Temp./Humidity)

Warehouse Storage Conditions

Baking Operation

Handling PWBs

PWBs are Moisture Sensitive.

Vacuum Sealed Bags should be opened just

prior to usage.

Open PWBs absorb moisture at room temp.

Supply Chain Controls

Understand Parts Movement and Staging

Customs Hold/ Warehouse Storage

Request temp./ humidity controls Data

Monitor seasonal temp. humidity changes

Track Product Performance

Supplier Staging User

Assembly Hub Temp./Humidity

Temperature and Humidity Record

TimeTemperature

20+/-5 C

Humidity

40-60%Initials

8 20C 50% ab

12 19C 49% ab

16 20C 48% ab

20 19C 47% ab

Warehouse Temp./Humidity Controls

PWB Baking Guidelines

Baking is one option to remove excess moisture

Baking can degrade “solderability”

Impact cost and cycle time

Oxidation of Surface Finish

Cause Intermetallic Growth

Process controls for Baking

Humidity controls inside Oven

Air/N2 Flow and Circulation

Stack Height of PWBs

Thermocouple Locations

Time/Temp.

Time Clock to start after oven has reached desired temp.

Baking Guidelines (contd.)

Understand the Surface Finish Impact

Lower temp. and longer bake times are effective

Typically 105-125C for 4- 6 Hours except OSP

Bake PWB prior to packaging at PCB house

Package in MBB bags with desiccant and Humidity Indicator Card

OSP Max 105C for 2 hours or supplier guideline

ENIG –IPC 4552

ENEPIG –IPC 4556

Immersion Silver – IPC -4553

Immersion Tin – IPC -4554

OSP – No standards yet

HASL – IPC6012/6016

Final Packaging and Labeling

MBB Bag Label

MBB Bag

Vacuum Seal

Labeling

HIC Card

PWB Packaging Specifications

Proper MSL Packaging

Desiccant Pack

Packaging Document

Audit Packaging Area

Implement Bake Cycle

PWB Packaging

Bake 120C -4 hours/package

within 6 hours -25/pack Add desiccant and HIC card

Shelf Life and Baking Guidelines by Surface

Finish

Immersion Tin 6 months

Return to Supplier

Remove ImmAg,

Bake , Reapply

ImmTin

IPC 4554

Shelf Life from

Shipment date

6 months

6 months

6 months

Finish Type

HASL

Immersion

Gold-

ENIG/ENEPIG

OSP

Selective Gold

Immersion

Silver

6 months

6 months

Return to Supplier

Remove OSP, Bake ,

Reapply OSP

Return to Supplier

Remove ImmAg, Bake

, Reapply ImmAg

IPC

6012/6016

IPC4553

Baking

Guidelines

120C 8 HRS

IPC Spec

IPC

6012/6016

4552/ 4556

N/A

120C 8 HRS

Return to Supplier

Remove OSP, Bake ,

Reapply OSP

2065.

841 783 754.

250 250 250 250

0

500

1000

1500

2000

2500

Q1-07 Q2-07 Q3-07 Q4-07

DPPM Monitoring

Supplier A- DPPM Chart

Lesson Learned

Understand Supply Chain

Clear Concise Documentation

Effective Process Controls

Training for MSL Handling

OEM/Supplier/CM Partnership

Respect the Material Limits

The End

Thank-you for attending this

training session.

Contact Info

mbora@psemi.com