MSD Council Info from Meeting at SMTAI 09
Wednesday, October 7, 2009
San Diego, CA
Updates from MSD Council Meeting - Mumtaz Bora, Peregrine Semiconductor
Contains MSD guidelines and current standards
A webcast was conducted by Mumtaz Bora and Steve Martell to review the current revisions of J-STD-033B.1 and J-STD-020D.1 and PWB MSD guidelines in 08/2009.
We will introduce MSD Webcasts for Asia as the need for this is increasing with the growth of the manufacturing base there. Next webinar will be November 30 at 11pm Central (9:30am Tuesday morning in India).
THe IPC D-35 committee is working on releasing a guideline for MSD Handling and Controls for PWBs. For questions, please contact John Perry, John.Perry@ipc.org
Presentations from MSD Session Options for controlling Moisture Sensitivity in Packages and PWBs During Assembly:
"Preventing Damage to MSD's and Bare Boards" - Kevin McCarten and Russell McCarten, XDry, Inc.; Jack Leonard, NAMCo
"The Coming Fourth Moisture-Sensitive
Package Dry-Baking Process" - Charles S. Leech Jr., Innovative Drying Co. LLC
"Pb-Free Reflow, PCB Degradation, and the Influence of Moisture Absorption" - Randy Schueller, Ph.D., DfR Solutions
Moisture-Sensitive Devices Webinar
Process Controls in Classifying, Handling, Storing and Baking Devices and PWBs
Wednesday, August 26, 2009
12pm to 1:30pm Eastern
Presented by Steven Martell, Sonoscan; and Mumtaz Bora, Peregrine Semiconductors
This presentation will give an overview of process controls in handling, storage and baking of Devices and PWBs, conducting supplier audits and some of the ongoing efforts in developing industry guidelines for Device and PWB handling and storage.
To order the recorded webinar, please contact Ryan Flaherty, ryan@smta.org.
SMTA
Moisture Sensitive Devices (MSD)
Council Survey
Dear MSD Council
Member,
Please e-mail your responses to this survey to joann@smta.org.
Using #1-8 below please tell us what sector of the
industry you work in?
1 - Aerospace
2 - Automotive/Harsh Environment
3 - Biomedical
4 - Defense
5 - RF/Microwave
6 - Telecommunications
7 - Cell Phones/Mobile
8 - Optoelectronics/MEMS
9 - Other
My industry sector number is______________
Please respond to the
questions below as they relate to your industry
sector. What impact do they have and what issues
are of concern to you?
Floor life derating for lead-free reflow.
Impact to yields due to MSL issues.
Baking cycle tape vs tray…cycle time impacts,
issues, cost.
J-STD 033B.1-items that are unclear need to
change, proposed additions.
J-STD 020D.1-items that are unclear need to
change, proposed additions.
J-STD-075-items that are unclear need to change, proposed additions.
Handling MSL parts-challenges.
MSL label issues.
Dry storage issues, cost impact.
Shelf life of packages.
PWB Moisture Absorption, MSL class, storage, and handling issues.
MSL Issues with Lead Free
Other topics, issues, or concerns that you
would like addressed.
MSD Council Meeting Minutes
Download the meeting presentation slides here
Wednesday, August 20, 2008 (in conjunction with SMTA International)
Disney's Coronado Springs Resort and Convention Center
Council Chairs:
Mumtaz Bora
Michelle Ogihara, Seika Machinery
Attendees:
Miguel Arroyo Colomer, Sypris Electronics
Karl Fink, Sypris Electronics
Bing Han, RIM
Abhinev Ajmera, RIT
Lawrence Pappas, Channel One Global
Lee Melatti, Channel One Global
Christophe Geffray, W.R. Grace
Sam Theabo, Plexus
Bill Barthel, Plexus
Jack Crawford, IPC
Mitch DeCaire, Cogiscan
M. Bora reviewed the current status of Industry standards for MSL classification -- J-STD-020D.1 (revision 03/08) and MSL Handling/Storage/Packaging standard -- J-STD 033B.1 (revision 01/07). These standards are available through the SMTA BookStore. Please contact Ryan Flaherty, ryan@smta.org, for details.
M. Bora reviewed general PWB handling guidelines and controls for components and PWBs during assembly rework.
Jack Crawford - IPC Director Certification and Assembly Technology provided copies of the recently released J-STD -075 to the attendees.
J-STD-075 -Classification of Non-IC Electronic Components for Assembly Processes is a new standard released for handling Moisture and temperature sensitivity in Non-IC packages such as passive components.
There is also a need in industry for a similar standard for power supply components. Per Jack Crawford, IPC is planning to address this need either as a new standard or as an update to J-STD -075 in the future.
MSL Control for PWBs
John Perry at IPC has formed IPC D-35 Printed Board Storage and Handling Subcommittee. We have had two teleconferences and prepared a draft document IPC1601-Guidance Document for Storage and Handling Issues for PWBs/Assemblies. Inputs are solicited from laminate suppliers, OEMs, CMs, etc. to make this a meaningful guideline. Please contact John Perry at JohnPerry@ipc.org if interested in participating on the committee.
The following guidelines are recommended for handling PWBs. MSD council will follow up with a webcast in October/November 2008 to address PWB handling issues.
OEMs to work with PWB suppliers to get guidelines for storage prior to package opening and after package opening.
PWBs should be treated as MSL classification 4, not to be left open on the floor more than 72 hours. This means to open packages, just prior to loading for screen printing as some of the higher Tg laminates tend to have more affinity for moisture absorption.
Three types of laminates are in use for SMT assembly:
- Low Tg -- 140 C and below
- Mid Tg -- 150C and above
- High Tg -- 170C and above
Careful understanding of the Tg (glass transition temperature and Td- Glass decomposition temp.) is important for selection of laminates for lead free reflow.
Most PWB suppliers guarantee shelf life for 6 months for unopened packages. Proper control and monitoring is essential after opening packages
For delamination issues, please work with supplier for bake procedures. Baking at 120- 140C for 6- 8 hours helps in drying the moisture. This is very dependent on the laminates used and the surface finish on the PWB (ENIG, OSP, HASL etc.). Baking is normally not recommended for OSP surface finish.
The following guidelines help in minimizing delamination issues during lead free reflow.
Bake at 120C- 140C for 4 hours prior to packaging at PWB supplier.
Package in Moisture barrier bags with dessicant and HIC card.
OEM storage in controlled conditions per J-STD -033B.1
OEM practice FIFO (first in/ first out) to minimize aging of PWBs.
Packages opened for IQC to be immediately resealed after inspection.
Packages on the floor to be opened just prior to assembly.
Assemblies waiting for rework/test debug should be properly dessicated.
PWB suppliers may charge a little bit more to do this type of packaging, but this cost is offset by the scrap reduction in production.
MSD Council has conducted one webcast for MSL Handling of PWBs in March 2008. Webcast was well received and generated interaction between attendees.
In 2009, we plan to have a one-day conference on MSL issues. Please check SMTA website for announcements.
New Materials for MSD Controls:
W.R. Grace has developed a new class of packages specific polymer desiccants in films/extruded form.
Innovative Drying has a new class of ovens that combine vacuum and baking.
This is provided as info only and not supported or solicited by SMTA.
Questions related to MSL standards should be submitted to the attention of mumtazbora@gmail.com or michelle@seikausa.com
Thanks to all the attendees for their participation. Special thanks to Jack Crawford for joining the MSD Council meeting and reviewing the IPC standards. We look forward to working with you and making MSL controls less confusing.
Purpose
The MSD Council is a
voluntary group, under the auspices of the SMTA,
dedicated to advancing the understanding and
practice of moisture sensitive devices control
in electronic assembly procedures and practices.
Specifically, the
council will serve industry professionals who
are SMTA members that have an interest in
moisture sensitive devices. |
Charter
The MSD Council will
be chartered to expand awareness through the
member-secure information available on-line here
and through educational programs, tutorials,
symposia, publications, events for extensive
networking, and possibly certification.
With the increasing need
for globalization in the area of industry
standards, and with the understanding and proper
practice of such standards, the MSD Council will
also establish formal and informal relationships
with international organizations that are
responsible for publishing related information.
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The Council represents engineering,
production management, quality assurance and
reliability, research, sales and marketing,
education, purchasing, and other functions.
Companies and institutions represented
include electronic manufacturers and users,
research laboratories, consultants,
universities, component manufacturers, and
manufacturers of related products.
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If
you are interested in serving on the Council,
contact SMTA administrator JoAnn Stromberg and
include your name, company, and contact
information.
While
the information on the page below is accessible
to all visitors, the information on the Self
Assessment and Resources pages is accessible
only to SMTA members.
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Introduction to MSD
Control
MSDs
are electronic devices encapsulated with plastic
compounds and other organic materials. Moisture
from atmospheric humidity will enter permeable
packaging materials by diffusion and
preferentially collect at the dissimilar
material interfaces.
During solder reflow, the
combination of rapid moisture expansion and
materials mismatch can result in package
cracking and/or delamination of critical
interfaces within the package.
These internal defects
are nearly impossible to detect during the PCB
assembly and test process. They lead to a number
of failure modes that have a negative impact on
manufacturing yields and cause early life
failure of the finished electronic products.
The risk of failure
during reflow is directly related to the
concentration of moisture at the critical
interface, which is near the centre of the
package. The maximum acceptable moisture content
and the rate of moisture diffusion vary for each
package.
To provide
suitable guidelines for assembly, the component
manufacturers must categorize each new device
based on how long it takes to absorb a critical
level of moisture in a standard production
environment. |
The proper storage and handling
procedures during PCB assembly are clearly
defined in the joint IPC/JEDEC standard
J-STD-033A Standard for Handling, Packing,
Shipping, and Use of Moisture/Reflow Sensitive
Surface Mount Devices, released in 1999 and
revised in July 2002.
The standard dictates
that moisture sensitive devices must be properly
classified, identified, and packaged in dry bags
until they are needed for PCB assembly. Once the
bags are opened, each moisture sensitive device
must be assembled and reflowed within a
specified timeframe.
Go to information on the status of
the forthcoming J-STD-033B revision, within
which lead-free appears to be the most critical
issue that is being addressed.
Basic proper handling
requires that the total cumulative exposure time
of each single reel or tray of sensitive
components must be tracked through the complete
manufacturing process, until all the components
are placed prior to reflow.
This basic material and
process control becomes very difficult to follow
in a high mix production environment, when
partial trays and reels are often removed and
re-loaded from assembly lines to be stored in
dry cabinets or dry bags.
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 The following issues are commonly found
to cause significant levels of escape with
existing manual procedures:
Clearly identify the trays and reels
containing moisture-sensitive devices.
Maintain a log sheet of cumulative exposure
time associated with each tray and reel.
Maintain the association between the log sheet
and the individual trays and reels.
Maintain an acceptable level of data
integrity/quality during manual logging and
date/time calculations.
Keep track of the remaining floor life and
expiration of MSDs while they are loaded on
placement machines.
Additional opportunities
are provided in the standard to account for dry
storage under certain conditions (Short Duration
Exposure) and to account for the ambient
manufacturing conditions (Derating due to factory
environmental conditions). Although they provide
additional flexibility for the users, these rules
and tables are even more difficult to implement
with a manual procedure.
The table and image above were
extracted from the joint IPC/JEDEC standard
J-STD-033A Standard for Handling, Packing,
Shipping, and Use of Moisture/Reflow Sensitive
Surface Mount Devices, released in 1999 and
revised in July 2002.
Top Ten Issues and
Misconceptions Associated with MSD Control
| Moisture sensitive devices are a serious
assembly issue that requires a high level of
control. A lack of proper control will result in
internal component damage during reflow due to
moisture expansion. This will typically create
insidious latent component defects that can
escape inspection and test. |
The
industry standards provide a set of guidelines
that are notoriously difficult to understand and
challenging to implement. Simplified manual
procedures tend to err on the conservative side
and result in a large number of unnecessary bake
cycles. This has a significant impact on lead
solderability and material flow.
|
The
following "Top Ten" list was provided courtesy of
Cogiscan and is intended to dispel certain
misconceptions related to MSD control in
electronics assembly.
1. In general, quality and
process engineers in the PCB assembly industry
have a number of misconceptions about MSD control,
because they have not been formally trained on the
most recent industry standards.
2. Many
internal procedures are based on obsolete industry
standards, such as the IPC-SM-786A and
JESD22-A112. These documents have been superseded by
the joint IPC/JEDEC standard J-STD-033A released
in 1999 and revised in July 2002.
 3. A sealed dry bag with desiccant does
not require high vacuum. A simple heat seal with
the proper quantity of desiccant is sufficient.
High vacuum can actually be detrimental by
increasing the amount of moisture diffusion
through the bag.
4. The bag seal date and the
12 months minimum shelf life is not an expiration
date. The decision to bake components is strictly
based on the status of the humidity indicator card
when the bag is opened.
5. The clock of
exposure time does not always stop when previously
exposed components are returned to dry storage
(dry cabinet or dry bag).
 6. Components that have never been
exposed and get stored in 10% RH dry cabinets may
have a limited storage life and exceed their
critical level without ever being exposed to
ambient conditions.
7. The default bake cycles
have been significantly increased from 24 hours to
48 hours at 125C, and from 8 days to 79 days at
40C. A table is provided in the IPC/JEDEC
standard J-STD-033A to reduce the bake cycle
according to the physical parameters of each
component (MSL and body thickness). To avoid
degrading solderability there is a cumulative
limit of 48 hours at 125C.
8. The floor life
clock is not reset by reflow. Assemblers must
track the remaining floor life of MSDs assembled
on boards for double-side reflow and rework.
9.
When factory ambient conditions exceed 30C / 60%
RH, the floor life indicated on the MS label is no
longer applicable. In this case the floor life
must be de-rated.
10. Boards must be baked
prior to rework to avoid damaging moisture
sensitive components during localized reflow. The
default bake cycle for populated boards is 10 days
at 90C.
SMTAI MSD Council Meeting Minutes
Wednesday 10/10/2007 9:30 AM - 11:30 AM
Attendees:
Miguel Arroyo Colomer ---Sypris Electronics
Karl Fink---- Sypris Electronics
Carl Schneider -- Inovaxe
Forrest Briggs--- Inovaxe
David Steele---Da-Tech Corp.
Oscar Salazar--Sypris Electronics
Mumtaz Bora - Kyocera _Wireless Corp.-- Co- Chair MSD Concil
Michelle Ogihara --- Seika Machinery---Co -Chair MSD Council
Minutes:
M. Bora reviewed the current status of Industry standards for MSL classification -- J-STD-020D (revision 06/07) and MSL Handling/Storage/Packaging standard -J-STD 033B.1 ( revision 01/07) .
MSL Classification needs to be redefined if packages are used for Lead free reflow as every 10C rise in peak reflow temp, MSL Class is reduced by 1 class level (e.g MSL 2A( 1 month floor life) to MSL 3 ( 7 days floor life).
J-STD -033B.1 is revised for several items.
New Humidity Indicator cards - 5/10/60% RH
HIC Indication
Short Duration Exposure and Oven Bake Cycles
Resetting and Pausing Floor Life at User Site
Shelf Life
Caution Labels
Items Discussed:
When packages are opened for IQC, they should be immediately resealed after inspection and stored in controlled storage conditions.
Passive components ( ceramic chip resistors and capacitors) , normally classified as MSL 1( unlimited floor life) have shown field failures after lead free reflow due to presence of moisture in the package. A new standard is being defined in industry for lead free passives MSL handling.
Paul Krystek at IBM is defining the draft for this standard.
The major impact of lead free reflow for OEMs is handling and storage of PWBs for lead free reflow as the incidence of delamination has increased during lead free reflow.
The following guidelines should be followed for handling PWBs. MSD council will follow up with a webcast to address PWB handling issues.
OEMs to work with PWB suppliers to get guidelines for storage prior to package opening and after package opening .
PWBs should be treated as MSL classification 4, not to be left open on the floor more than 72 hours . This means to open packages , just prior to loading for screen printing as some of the higher Tg laminates ted to have more affinity for moisture absorption.
3 types of laminates are in use for SMT assembly.
Low Tg -- 140 C and below
Mid Tg -- 150C and below
High Tg 170 C and above
Careful understanding of the Tg ( glass transition temperature and Td- Glass decomposition temp.) is important for selection of laminates for lead free reflow.
Most PWB suppliers guarantee shelf life for 6 months for unopened packages. Proper control and monitoring is essential after opening packages
For delamination issues, please work with supplier for bake procedures. Baking at 120-140C for 6-8 hours helps in drying the moisture.
This is very dependent on the laminates used and the surface finish on the PWB ( ENIG, OSP, HASL etc.) . Baking is normally not recommended for OSP surface finish.
The following guidelines help in minimizing delamination issues during lead free reflow.
Bake at 120C- 140C for 4 hours prior to packaging at PWB supplier.
Package in Moisture barrier bags with dessicant and HIC card.
OEM storage in controlled conditions per J-STD-033B.1
OEM practice FIFO( first in/ first out) to minimize aging of PWBs.
Packages opened for IQC to be immediately resealed after inspection.
Packages on the floor to be opened just prior to assembly.
Assemblies waiting for rework/test debug should be properly dessicated.
PWB suppliers may charge a liitle bit more to do this type of packaging, but this cost is offset by the scrap you minimize in production.
Question related to both MSL standards should be submitted to mbora@kyocera-wireless.com. We will work with the industry experts to get these answered.
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