Doc.ID COMPONENT_SHELF_LIFE
Revision: 8.0
Issue Date: 08/02/2012
GE Power Electronics Business
STORAGE REQUIREMENTS (SHELF LIFE) FOR COMPONENTS,
MATERIALS and PWBs
Author:
Anjana Shyamsundar
Jr Component Engineer
Reviewers:
Alessandro Cervone
Technical Manager
Component Reliability & Engineering
601 Shiloh Road
Plano, TX 75074
972-244-9652
601 Shiloh Road
Plano, TX 75074
972-244-9370
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Revision: 8.0
Issue Date: 08/02/2012
Change History:
Issue
1.0
2.0
3.0
4.0
Reason for changes
Original issue
Added DA product 7.0
Format change
Added Certificate of Authenticity with traceability back to the manufacturer
requirement if procuring material from brokers
Name
A. A. Cervone
J. Orem
A. A. Cervone
A. A. Cervone
Date
6/2/2005
11/8/2005
11/9/2005
10/30/2006
5.0
Change TEPS to Lineage Power. Remove Paragraph 4.4 PCB without
Desiccant and HIC Card. Replace with MPS 179000 Issue 2. Eliminate
MPS 179000 Document. Added References. Updated issue of J-STD-033
to B.
Add Section for Magnetic Components that use PCB Materials. Add
paragraph to PCB Shelf Life to address Handling of Out of Date PCB
Materials.
Added Section for PWB Packaging Bag (section 3.1) and updated HIC card
indication from 50% to 10% in sections 4.2 and 4.4, Chapter 2.
Shelf life Matrix for PWB update: PWB shelf life of ENIG and HASL from
6 months to 12 months. HIC indication changed from 50% to 10%.
Added notes on packaging in summary.
Added Picture of Metal Aluminum Bag
Replace Lineage Power with GE Power Electronics.
Harmonized with CHK Shelf Life Material Procedure
R. Roessler
A. A. Cervone
07/14/2008
R. Roessler
12/17/2009
A. Shyamsundar
10/27/2011
6.0
7.0
8.0
A.A .Cervone
8/2/2012
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Chapter 1
Table of Contents
Chapter 1
1. INTRODUCTION .................................................................................................................................................................... 5
1.1 Purpose........................................................................................................................................................... 5
1.2 Scope ............................................................................................................................................................. 5
2. GENERAL ................................................................................................................................................................................ 5
2.1 References........................................................................................................................................................... 5
2.2 Technical Assistance........................................................................................................................................... 5
2.3 Acronyms / Definition ........................................................................................................................................ 6
2.4 Responsibilities and Ground Rules ..................................................................................................................... 8
2.5 Procurement of Material from Brokers Or Foreign Distributors ........................................................................ 9
2.6 List of Items to be Audited Monthly................................................................................................................. 10
3. DRY PACK SHELF LIFE REQUIREMENT ..................................................................................................................... 11
3.1 Active and Passive Devices (SMT) ................................................................................................................. 11
4. NON-DRY PACK SHELF LIFE REQUIREMENTS ....................................................................................... 12
4.1 ICs (SMT) ............................................................................................................................................... 12
4.2 Power Semiconductors ............................................................................................................................ 13
4.3 High Voltage/High Current Power Diodes .............................................................................................. 14
4.4 Capacitors ................................................................................................................................................ 15
4.5 Sheet-Metal Fabrication........................................................................................................................... 15
4.6 Plastic Parts.............................................................................................................................................. 16
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4.7 Passive Components ................................................................................................................................ 16
4.8 Electrical Connectors ............................................................................................................................... 16
4.9 Electrical Fuses ........................................................................................................................................ 17
4.10 Labeling ................................................................................................................................................. 17
4.11 Fans ........................................................................................................................................................ 17
4.12 Metal Fabricated Parts (ex: screws, washers, standoffs, spacers, inserts, studs, rivets, thumbscrews,
clips, clamps, etc) ......................................................................................................................................... 18
4.13 Miscellaneous (ex: STORAGE MEDIA, DISK DRIVES, etc) ........................................................... 18
4.14 Magnetic Components using PCB Materials ........................................................................................ 18
5. TESTING REQUIREMENTS ............................................................................................................................. 19
5.1 Solderability Testing ............................................................................................................................... 19
6. STORAGE BAG REQUIREMENTS ................................................................................................................. 21
7. PROCUREMENT OF MATERIAL FROM BROKERS OR FOREIGN DISTRIBUTOR………21
8. RETENTION OF COMPONENTS FOR DISCONTINUED AVAILABILITY (DA) PRODUCT
(LAST TIME BUY) ............................................................................................................................................. 22
8.1 Scope ....................................................................................................................................................... 22
8.2 Procedure ................................................................................................................................................. 22
8.3 Component Review Process .................................................................................................................... 22
Chapter 2
PRINTED CIRCUIT BOARDS .............................................................................................................................. 25
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1. INTRODUCTION
1.1 PURPOSE
The intent of this specification is to define the storage requirements for electronic components, printed
wiring boards, connectors and mechanical piece parts and adhesives used in GE Power Electronics
products, covering the Policy for Shelf Life, Testing Requirements, and Storage Bag Requirements. Shelf
life status for all materials must be confirmed prior to kitting to the production floor.
1.2 SCOPE
This specification contains specific requirements for storage of Semiconductor Devices, Printed Circuit
Boards, Passive Components, Sheet-Metal Fabrication, Plastics, Electrical Connectors, Fans and
miscellaneous other components/materials such as adhesives and solders varnishes, accelerators, thermal
compounds and batteries used in or distributed with GE Power Electronics’ products.
This procedure shall be followed by all personnel and outside component distributors dealing with age
sensitive material.
2. GENERAL
2.1 REFERENCES
2.1.1 ASSOCIATED DOCUMENTS
ISSUE
REFERENCES
2.1.2 INFORMATION FURNISHED BY GE POWER ELECTRONICS
Refer to Matrix for the latest issue of the following:
DOCUMENT NUMBER
MPS 179000
TITLE
MPS 179000 - Printed Wiring Board Shelf Life
Storage & Baking – retired and superseded by
this document
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2.1.3 INDUSTRY STANDARDS
DOCUMENT NUMBER
ASTM F 392-93
TITLE
Standard Test Method for Flex Durability of
Flexible Barrier Materials
Handling, Packing, Shipping and Use of
Moisture/Reflow Sensitive Surface Mound
Devices
Solderability Tests for
Component Leads, Terminations, Lugs, Terminals
and Wires
Solderability Tests for Printed Boards
Packing Materials Standards for Protection of
Electrostatic Discharge Sensitive Devices
Terms and Definitions
Solder mask
Acceptability of Assembly Workmanship
Laboratory Test Methods, Solderability and
Related Affects
Generic Performance Specification of PWB's
Qualification and Performance of Rigid PWB's
J-STD-033B or later issue
J-STD-002A
J-STD-003A
EIA 541
IPC-T-50
IPC-SM-840
IPC-A-600
IPC-TM-650
IPC-6011
IPC-6012
2.1.4 PRINCIPLE DRAWING
DRAWING NUMBER
ISSUE TITLE
2.2 TECHNICAL ASSISTANCE
For technical assistance, contact GE Power Electronics Component Engineering Manager
Alessandro Cervone +1 (972) 244-9370.
2.3 ACRONYMS / DEFINITIONS
2.3.1 ACRONYMS
BGA -Ball Grid Array
CSR -Controlled Stock Room
DCC -Document Control Center
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DIMM
ENIG
ESD
HASL
HIC
IC
-Dual In-Line Memory Module
-Electroless Nickel/Immersion Gold Plating
-Electro-Static Discharge
-Hot Air Solder Level
-Humidity Indicator Card
-Integrated Circuits
ICT -In Circuit Test
MBB -Moisture Barrier Bag
MIC -Moisture Indicator Card
MSD -Moisture Sensitive Device
MSL -Moisture Sensitivity Level
OSP -Organic Solderability Preservative
PCB -Printed Circuit Board
RH -Relative Humidity
SIMM -Single In-Line Memory Module
SMD -Surface Mount Device
SMT -Surface Mount Technology
2.3.2 DEFINITIONS
2.3.2.1 Controlled Stock Room:
2.3.2.1.1 Temperature: The stock room is to be maintained at a temperature of 20°C ±10 °C. In addition,
temperature variations of more that 10 °C are not permitted in any 24-hour period. Components
that have been exposed to temperature extremes or variations that are outside these limits must
undergo appropriate inspection/test procedures before any use/shipment.
2.3.2.1.2 Humidity: Shall be controlled between 30-60% relative humidity. For optical connectors and
components, it is recommended that humidity levels be lower than 60% due to the hygroscopic
nature of glass fiber and the potential for cracking on the surface of the fiber when handled after
prolonged exposure to humidity..
2.3.2.1.3 ESD Protection: Packaging for all sensitive components needs to be intact, no rips or punctures,
and fully covering the components/finished boards.
2.3.2.1.4 Unit Packaging: Undamaged, with no distortions or sign of impact. SMT reels need to be
coiled, with no loose components. Loose electronic components, i.e. in bags, are not advised.
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Integrated Circuit Components and BGA devices should be in tray or tape & reel. Bags should
not be broken.
2.3.2.1.5 UV Protection: All items must be protected from direct sunlight or UV light at all times.
2.3.2.1.6 Electrical components and boards shall be stored separate from any chemical storage.
2.3.2.1.7 Shock & Vibration: The stock room shall be located away from any source that could induce
shock or vibration ( e.g. stamping presses or high traffic aisles).
2.3.2.1.8 Atmosphere (including Dust and Contamination): Environment should reduce the impact of
corrosion and dust. Please note that the use of the ESD Intercept bag (see Table 1) will protect
against the environment.
2.3.2.2 Shelf Life:
2.3.2.2.1 The time within which an electronic component or mechanical piece part can be stored, at a
given ambient condition, is usable without testing, evaluation or special conditioning. Usage of
a component beyond the specified shelf life could compromise product long term reliability.
2.3.2.3 Floor Life
2.3.2.3.1 The allowable time period, after removal from a moisture barrier bag and before the solder
reflow process, for a moisture-sensitive device to be exposed to a factory ambient not exceeding
30°C and 60% RH.
2.3.2.4 Date Code:
2.3.2.3.1 The manufacturing date marked on the component, reel or box (lowest packaging level where it
fits).
2.3.2.5 Bags:
2.3.2.5.1 Antistatic Bags
Antistatic bags are typically coated with a topical antistat agent that helps minimize the
generation of a static imbalance from triboelectric generation or contact and separation (i.e.,
definition of antistatic). Some antistatic bags are made with an antistat built into the films layers
and tend to be more reliable and cleaner then the topically treated ones. A good bag has
antistatic properties on both the inside and outside of the bag’s film construction.
2.3.2.5.2 Dissipative Bags
Bags with the films surface resistance in the dissipative range are preferred because charge
dissipates across the surface at a controlled rate. Most dissipative bags also have the property of
being antistatic. These are good general bags to be used in non-critical environments.
2.3.2.5.3 Metalized Shielding Bags
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Metalized shielding bags have either a metal film embedded into the bag film construction or
coated onto an existing layer. This metal film acts as an electrical shield against electrical
discharges from the outside of the bag. Depending on the energy and duration of the discharge
and the thickness of the metal film, an ESD event is typically spread out over the outer surface
of the metal film and if fully enclosed, i.e. the bag is sealed, then the charges current from the
ESD event is contained to the outside (outer surface) of the metal film, i.e., providing a region of
no electrostatic fields within the bag, thereby protecting the contents within. This effect is
known as the Faraday Cage Effect and is commonly used in controlling ESD via metalized
shielding bags, conductive bags and the conductive tote box with a cover.
2.3.2.5.4 Moisture Barrier Bags (MBB)
A Moisture Barrier Bag is designed to minimize the transmission of water vapor and used to
pack moisture sensitive devices. The bags should be ESD safe, flexible, and puncture resistant.
o
Water vapor transmission rate should be <= 0.002 g/100 sq.in. in 24 Hours at 40 C after flex
testing per condition E of ASTM F 392-93.
2.3.2.4.5 ESD bags should be inspected before reuse by an internal statistical sampling plan as they
typically have a finite reuse life.
2.4 RESPONSIBILITIES AND GROUND RULES
2.4.1 Receiving Inspection (R/I) personnel are responsible for the identification and
marking of age sensitive material.
2.4.2 Stock Room personnel are responsible for ensuring that the age sensitive items
with expired dates are not issued.
2.4.3 Manufacturing Engineering personnel are responsible for the identification of
age sensitive materials and the evaluation and disposition of the items with
expired shelf life labels.
2.4.4 Age sensitive materials shall be stored in the same stock area for ease of control.
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2.4.5 QA is responsible for performing random audits on a monthly basis of the items
in stock requiring shelf life controls. The audit will be based on the controlled
list of shelf life control part numbers and all parts shall be audited/ verified.
2.4.6 The end user is responsible for assuring that material with an expired shelf life
label is not used on deliverable products.
2.5 PROCEDURE
2.5.1 Whenever age sensitive materials are received, Receiving Inspection personnel will indicate
the expiration date on each, outer container and each individual inner container large enough
to accept the label by means of using the
appropriate date stamp and shelf life label. The
expected expiration dates will be determined by one of the following methods:
2.5.2
2.5.3
2.5.4
2.5.5
The actual expiration date indicated on the item.
A date determined by date of manufacture of the product combined with manufacturers
stated shelf life.
If the above information is not available, Manufacturing Engineering shall determine an
appropriate expiration date, which will typically be set for nine (9) months from the date
received.
Upon issuing all items that have shelf life identification or expiration dates on their labels,
Stock Room personnel will verify that the dates have not expired yet.
2.5.5.1 If the date indicated on the label is expired, then Stock Room personnel will contact
Manufacturing Engineering (M.E.) for evaluation of the items. If the M.E. approves
the use of this material, they will place their initial and date on the part umber label
within the expiration date stamp.
2.5.5.2 If not approved by the M.E., then the material will be turned over to the MRB for
disposition (usually to scrap) as per the applicable procedures.
2.5.6
When numerous items (such as small tubes or adhesive bottles) are inside a large
container/box with the part number label, Stock Room personnel must keep the original
container until all contents have been used up. If however, the original container must be
discarded due to space limitations, then the original label must be carefully removed and
placed on the new (smaller) container. A shelf life label must always be on the outermost box
in the stock room. Inner items with different expiration dates cannot be stored in the same
container.
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2.5.7
Whenever material with a shelf life label is broken down into smaller containers, the smaller
container must have a shelf life label indicating the same expiration date as the original.
2.6 LIST OF ITEMS TO BE AUDITED MONTHLY
RTV ADHESIVE
SOLDER WIRE, .062, SN63
1544 FLUX
CM8 SOLDER MASK
SOLDER WICK, NO CLEAN .11 W
SOLDER WIRE, .031, SN63
COBAR 390 FLUX
COBAR 309 FLUX THINNER
SOLDER PASTE, NO CLEAN
SOLDER,PASTE,PB-FREE,SMD ASSEMBLY
ADHES., CYANOACRYLATE, BLK
ACCELERATOR
ADHESIVE, INSTANT GLUE
ADHESIVE, HOT MELT
ADHESIVE, EPOXY, REPAIRABLE
SMD EPOXY ADHESIVE
CONFORMAL COATING
ADHES., CYANOACRYLATE
THREADLOCKER, PURPLE
Varnish AC-43
CC-1105 VARNISH
ALL PRINTED CIRCUIT BOARDS
3. DRY PACK SHELF LIFE REQUIREMENTS
If devices are stored in a Moisture Barrier Bag (MBB) containing desiccant and a Humidity Indicator
Card (HIC) are to be considered moisture sensitive. Located on the MBB will be a caution label
containing a Moisture Sensitivity Level (MSL) of 1-6. Note: Level 1 devices are not considered moisture
sensitive and are not labeled as such. The handling of these devices must be in accordance with IPC-JSTD-033B or later version. The following procedures are to be followed to determine the shelf life and
procedures for verifying moisture exposure.
3.1 ACTIVE AND PASSIVE DEVICES (SMT):
3.1.1 Shelf life of the dry packed components is generally limited by the MBB expiration date, which is
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typically located on the caution or bar code label. The MBB expiration date is typically one year
from the bag seal date, but this is not always the case. Manufacturers are allowed to specify an
MBB expiration date, which may be longer than 1 year. If there is no expiration date on the outside
of the MBB use 1 year from the manufacture date to determine what additional steps maybe
required.
3.1.2 If stored in CSR beyond 12 months, solderability tests must be carried out per Section 5.
3.1.3 If stored in a CSR and the MBB expiration date has not expired:
3.1.3.1 For components issued to the shop floor, floor life should not be exceeded. If floor life is exceed,
J-STD-033B, or later version, must be followed to reset shelf life and repackaging.
3.1.3.2 Inspect the MBB for damage such as holes, gouges, tears, punctures, openings of any kind, or
excessive wear.
3.1.3.3 If there is no damage, no further inspection is necessary.
3.1.3.4 If the bag is damaged or shows signs of excessive wear open the MBB by cutting the top of the
bag near the sealed edge and discard.
3.1.3.3.1 Remove the HIC card and verify that the 10% dot is blue the parts have not been
exposed and may be repackaged per J-STD-033B or later version. NOTE:
When repackaging these devices if the exposure is less than 30 minutes the parts
are to be resealed in a new MBB with a fresh HIC and desiccant. A tracking
label must accompany the sealed bag indicating the date and time opened, the
date and time resealed, and the new MBB expiration date that is one year from
the reseal date.
3.1.3.3.2 If the 10% dot on the HIC is not blue (meaning it is any stage of transition from blue to pink)
this indicates the moisture level has been exceeded and the parts must be baked per J-STD-033B
or later version.
3.1.3.4 Please refer to J-STD-033B, or later version, for more detailed instruction.
3.1.4 If stored in a CSR and the MBB expiration date has been exceeded:
3.1.4.1 Inspect the MBB for damage such as holes, gouges, tears, punctures, openings of any kind or
excessive wear.
3.1.4.1.1 If the MBB shows any signs of damage or excessive wear it is to be discarded.
3.1.4.2 Open the MBB by cutting the top of the bag near the sealed edge.
3.1.4.2.1 Remove the HIC card and verify that the 10% dot is blue the parts have not been
exposed and may be repackaged per J-STD-033B or later version. NOTE: When
repackaging these devices if the exposure is less than 30 minutes the parts are to
be resealed in its existing MMB with a fresh HIC and desiccant. A tracking label
must accompany the sealed bag indicating the date and time opened, the date and
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time resealed, and the new MBB expiration date that is one year from the reseal
date.
3.1.4.2.2 If the 10% dot on the HIC is not blue (meaning it is any stage of transition from blue to pink)
this indicates the moisture level has been exceeded and the parts must be baked per J-STD-033B
or later version.
3.1.5 If baking is required the cumulative bake time when temperature is >90°C and up to 125°C shall not
exceed 48 hours. If baking temperature is <90°C, there is no limit on baking time.
3.1.6 If baked, a tracking label must accompany the sealed bag indicating the date and time opened, the
date and time resealed, the temperature and cumulative duration of the baking cycle(s) and the new
MBB expiration date that is one year from the reseal date.
3.1.7 Parts should be repackaged immediately after the baking cycle or stored in a 5% RH dry cabinet
until being repackaged according to IPC J-STD-033B or later version.
4. NON-DRY PACK SHELF LIFE REQUIREMENTS
4.1 ICS (SMT):
4.1.1
SMT integrated circuits and opto-isolators should have an MSL rating (typically 1) and as such
may not be shipped in an MBB by the manufacturer. Since these packages do absorb moisture,
they can exhibit “pop-corning” during reflow. This phenomenon can lead to die cracking or may
result in higher field risk of failure due to a number of mechanical stresses applied to the die.
Such stresses may result in die cracking, die delamination from the plastic causing tensile stresses
on the bond wires or any number of other reliability affecting phenomena.
4.1.2
The following photograph shows plastic package “pop-corning” effects, after reflow, as exhibited
by plastic package bulging and cracking.
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Photo 1
Package overview showed the
gross bulging and cracks on the
top package.
4.1.3
Photo 2
Photo 3
Crack and bulge also found at the
bottom package.
Delamination observed over the
die and several leads during the
top scan.
It is recommended that non-dry-packed SMT IC’s be stored in CSR. The shelf life of these
components can be extended to 2 years. Beyond 2 years, a solderability test is required as
per manufacturer’s recommendations.
4.2 POWER SEMICONDUCTORS
4.2.1 HIGH VOLTAGE POWER TRANSISTORS
4.2.1.1 Regardless of whether a high voltage (>200V) power MOSFET is SMT or Through-hole, TO-247
plastic packages absorb moisture. Micro-cracks in the passivation can cause trapped ionic
contamination to become mobile in the presence of moisture and an electric field. This leads to
increased leakage current and a lower breakdown voltage resulting in probable device electrical
failure when installed in a circuit. The following figure shows this phenomenon as evidenced in a
1000V MOSFET:
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Good Device
BVdss = 850V
BVdss = 650V
BVdss = 450V
Leakage Current of 1000V MOSFETs as Received from a non-CSR Environment
4.2.1.2 Therefore, it is recommended that all high voltage power transistors be stored in CSR. The
shelf life of these components can be extended to 12 months. Beyond 1 year, a solderability
test is required as per manufacturer’s recommendations.
4.3 High voltage/high current power Diodes
4.3.1 These devices (>100V, > 10A) are found in a variety of packages (through–hole and SMT).
4.3.1.1 The through-hole devices may exhibit similar moisture absorption characteristics as the high
voltage MOSFETs. Hence, it is recommended that all high voltage/high current power diodes
be stored in CSR. The shelf life of these components can be extended to 12 months. Beyond
1 year, a solderability test is required as per manufacturer’s recommendations.
4.3.1.2 SMT devices should be rated with an MSL figure (typically 1). If these devices are not received
in an MBB, then they should be treated similar to the high voltage power MOSFETs. These larger
packages do absorb moisture and when subjected to reflow temperatures may result in internal
mechanical damage. The following photograph shows the result of wirebond breaking due to
moisture expansion inside the device during reflow:
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Example of Diode Bond-wire Separation Resultant from Moisture Absorption and Reflow
4.3.1.3 Therefore, it is recommended that all high voltage/high current power diodes be stored in
CSR. The shelf life of these components can be extended to 12 months. Beyond 1 year, a
solderability test is required as per manufacturer’s recommendations.
4.4 CAPACITORS:
4.4.1 Electrolytic: 2 years
4.4.1.1 If in CSR: For components that are greater than 2 years from Manufacturer’s Date Code that are
slated for demand, please contact GE Power Electronics for disposition prior to performing
solderability testing, bake out and reforming component (apply voltage to reform component).
4.4.2 Tantalum/Film/Ceramic/etc: 2 years
4.4.2.1 If in CSR: Any deviation from this guideline will have to be backed up with a solderability test
as defined by the manufacturer.
4.5 SHEET-METAL FABRICATION AND PLASTICS:
4.5.1 SHEET-METAL FABRICATION:
4.5.1.1 Plated metals: 1 year
4.5.1.2 Powder paint coated metal parts: 2 years
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4.5.1.3 Metal parts are typically post-plated or pre-plated to increase the corrosion resistance. The
coatings are anodic to the base metal corrode preferentially thereby protecting the underlying
metal, like zinc over steel. In addition the zinc is further protected by a chromium conversion
coating. The examples of cathodic coatings are tin, copper, chromium, silver, gold, and nickel on
steel, accelerate the corrosion of the underlying material if a break in the film develops and
electrolyte is present.
4.5.1.4 Protect metal parts by packaging. Keep metal parts in a controlled environment for storage.
4.5.5 If beyond 1 year, visually inspect metal parts for oxidation, corrosion, and/or damage. Sample shall
be submitted to Quality Dept. for inspection. It may be possible to use this material based on this
inspection and subsequent 1 year.
4.6 PLASTIC PARTS:
4.6.1 3 years
4.6.2 If in CSR: With guaranteed storage conditions
4.6.2.1
Pure plastic components: 4 years.
4.6.2.2
If beyond 4 years, a sample can be submitted to the Quality department for inspection. It
may be possible to use this material based on this inspection and subsequent 6 month
sample inspections.
4.6.2.3
Plastic components coated with metal for shielding purposes: 3 years.
4.6.2.4
If beyond 3 years, a sample can be submitted to the Quality department for inspection. It
may be possible to use this material based on this inspection and subsequent 6 month
sample inspections.
4.7 PASSIVE COMPONENTS:
4.7.3 SMT resistors, SMT capacitors, Chip Inductors, Other: 2 years
4.7.3.1 If in CSR: If storage conditions are guaranteed, shelf life can be extended to 3 years.
4.7.3.1.1 Beyond 3 years, a solderability test is required as per manufacturer’s recommendations. Please
contact GE Power Electronics Product Engineer/SBE for disposition prior to performing kitting
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or any tests including bake out and solderability.
4.8 ELECTRICAL CONNECTORS
4.8.1 Electrical connectors: 1 year
4.8.2 All electrical connectors are recommended be stored in CSR to prevent moisture, mildew or other
potential deterioration of the external packaging materials.
4.8.3 It is highly recommended that connectors are stored in original manufacturer’s packaging.
4.8.4 If beyond 1 year, test connectors for solderability per IPC/EIA J-STD-002A Category I. In addition
to performing the solderability examination, at the discretion of the component engineer,
examination such as cross-sections and/or suitable alternative may be appropriate. It may be
possible to use this material based on this inspection and subsequent 90 days if this material pass the
solderability test.
4.9 ELECTRICAL FUSES
4.9.1 Electrical fuses: 1 year
4.9.2 All electrical fuses are recommended be stored in CSR to prevent moisture or other potential
deterioration of the external packaging materials.
4.9.3 It is highly recommended that fuses are stored in original manufacturer’s packaging. Do not expose
fuses to corrosive gas, sea breeze, visible dust, direct sun rays, and pressure that can cause
deformation and/or degradation of product.
4.9.4 If beyond 1 year, test connectors for solderability per IPC/EIA J-STD-002A Category I. . In
addition to performing the solderability examination, at the discretion of the component engineer,
examination such as cross-sections and/or suitable alternative may be appropriate. It may be
possible to use this material based on this inspection and subsequent 90 days if this material pass the
solderability test.
4.9.5 After 1 year from the date of manufacturing, check for any change in the electrical characteristics
described in the specification.
4.10 LABELING:
4.10.1 Label: 12 months.
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4.10.2 The shelf life of labels is approximately 1 year if they are stored unopened, in their original plastic
wrapping, free from exposure to direct light, in a clean area which has an ambient temperature of
16 to 30 degrees Celsius, maximum 50 percent relative humidity.
4.10.3 Labels shall not be subjected to direct sunlight, high humidity, and or high temperature.
4.10.4 After 1 year from the date of manufacturing, check for label adhesive strength described in the
specification or consult with the manufacturer.
4.11 FANS
4.11.1 Fan: 1 year
4.11.2 All fans are recommended be stored in CSR to prevent moisture or other potential deterioration of
the external packaging materials.
4.11.3 It is highly recommended that fans are stored in original manufacturer’s packaging.
4.11.4 Fans don’t last forever; bearing lubricants dry out under unfavorable environmental conditions
therefore reducing the life of the bearing. After 1 year from the date of manufacturing, check for
any change in the characteristics described in the specification or consult with the fan
manufacturer.
4.11.5 Fans that are beyond the manufacturer’s warranty period should not be used.
4.12 METAL FABRICATED PARTS (EX: SCREWS, WASHERS, STANDOFFS, SPACERS,
INSERTS, STUDS, RIVETS, THUMBSCREWS, CLIPS, CLAMPS, ETC)
4.12.1 Plated metals parts: 1 year
4.12.2 Non-plated metal parts: 1 year
4.12.3 Metal parts are typically plated to increase the corrosion resistance. Some metal parts are unplated, like stainless steel.
4.12.4 Protect metal parts by packaging.
4.12.5 If beyond 1 year, inspect metal parts for oxidation, corrosion, and damage. Sample shall be
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submitted to Quality Dept. for inspection. It may be possible to use this material based on this
inspection and subsequent 1 year.
4.13 MISCELLANEOUS (EX: STORAGE MEDIA, DISK DRIVES, ETC)
4.13.1 Must be stored in a controlled environment
4.13.2 Must be stored in bag or sealed box
4.13.3 Magnetic media must be stored away from magnetic fields
4.14 MAGNETIC COMPONENTS CONTAINING PCB MATERIAL
4.14.1 FINISHED MAGNETICS
Finished Magnetics that use PCB materials shall be packed in moisture barrier bags with desiccant
and HIC as outlined in the PCB Chapter 2 segment of this document. GE Power Electronics Shelf
Life Policy for PCB material type magnetics shall be treated no differently than PCBs’. Magnetic
PCBs’ that are over 12 months old shall undergo baking and moisture vulnerability testing to
verify lead free processability as well as solderability. Finished Magnetics using PCBs’ over 20
months old shall be scrapped.
4.14.2 MAGNETIC PCB UNASSEMBLED
Unassembled Magnetic PCBs’ shall follow the GE Power Electronics Shelf Life Policy as outlined
in Chapter 2 of this document beginning on page 20. It will be the responsibility of the Magnetic
Supplier to fully comply and show proper documentation that it is in compliance with the Rules
outlined in this document.
5. TESTING REQUIREMENTS
5.1 SOLDERABILITY TESTING:
When material is identified as beyond shelf-life, this procedure will be used for determining if it is
acceptable to be used to complete assembly requirements.
IPC/EIA/JEDEC J-STD-002A (Component Leads, Terminations, Lugs, Terminal Wires) and J-STD003A (PWBs) shall be followed for solderability testing.
Table 1 - IPC/EIA/JEDEC J-STD-002A Solderability Test Selection Component Type
Test Method
Through-Hole
Surface Mount
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Mount
A – Dip & Look Test (Leaded Components)
B – Dip & Look Test (Leadless Components)
D - Resistance to Dissolution of Metallization
Test
S – Surface Mount Process Simulation Test
5.1.1
Leadless
JLead
X
Gull
Wing
X
X
X
X
X
X
X
X
X
Solderability of PWB's and Baking Precautions
5.1.1.1 Considerations related to storage and shelf-life expectancy
5.1.1.2 No product should be in inventory for more than one (1) year.
5.1.1.3 Moisture uptake is a function of surface exposed, time, and relative humidity. All plastics are
sensitive to some degree.
5.1.1.4 Solderability is a function of the thickness and integrity of the solder finish applied to the PWB.
A thickness of 200 microinches of tin or tin based finish will provide a one (1) year shelf-life, if
stored properly. See Figure 2 (below) for thickness vs. solderability expectation. The parts plated
at 200 microinches will have areas thicker (faces) and thinner (edges). The User must make sure
the plating distribution is known and acceptable.
5.1.1.5 Solderability Graph for Shelf-Life vs. Plating Thickness [tin (Sn) plated systems only]. This is a
Guideline Reference.
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5.1.2 Solderability Limitations
5.1.2.1 Baking can cause oxidation and excessive intermetallic growth on the terminations (J-STD-033B
Section 4.2.7.1). The IPC standard specifies that the cumulative bake time at temperatures >90 C
SHALL NOT exceed 48 hours. This section of the standard defines the acceptable amount of
baking that can be performed before discarding components. The standard also discusses the need
to perform solderability testing when needed.
5.1.2.2 It should be noted that excessive intermetallic growth can degrade solderability more severely than
mere oxidation of the surface finish. Fluxes can effectively reduce many surface oxides and allow
proper wetting and subsequent solder joint formation. However, intermetallic layers are thicker
than most oxide layers, are relatively stable, and are impervious to fluxes. If baking causes the
surface finish to be consumed by intermetallic growth, the resulting surface is not solderable.
5.1.3 “Dip and Look” Test
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Note: Fine pitch gullwing leads (spacing < 20 mils) cannot be tested adequately with the dip & look
method. Also, dip & look is inappropriate for BGA’s.
5.1.3.1 IPC/EIA/JEDEC J-STD-002B (Component Leads, Terminations, Lugs, Terminal Wires)
and J-STD-003 (PWBs) shall be followed.
6. STORAGE BAG REQUIREMENTS
6.1.1 Storage bag materials shall provide a moisture barrier (MBB as defined in IPC/JEDEC J-STD-033)
and be electrostatic dissipative.
6.1.2 Material shall exhibit a surface resistivity >105 and <1012 Ohms/Square.
6.1.2.1 Static-safe material test specifications are defined in EIA 541 “Packing Materials Standards for
Protection of Electrostatic Discharge Sensitive Devices,” from the Electronic Industries
Association.
6.1.2.2 All packaging materials must be initially qualified and periodically re-qualified based on local
needs.
6.1.3 Material shall be non-contaminating and have non-volatile construction.
6.1.4 Material shall not contain amines, amides, or ammonia compounds
6.1.5 Material shall provide protection from sulfur and chlorine atmospheric corrosive gases as required.
6.1.6 Moisture vapor dry packaging shall have a water vapor permeation rate <=0.002g/100sq.in. /24hrs.
7. PROCUREMENT OF MATERIAL FROM BROKERS OR FOREIGN DISTRIBUTORS
7.1 Purchasing of material from brokers or unapproved foreign distributors is discouraged. If the
need for such procurement arises, as in line down situations, the Commodity Manager shall
obtain approval from the appropriate Component Engineer.
7.2 Under these circumstances, the following information is required prior to approval request:
7.2.1.1 Manufacturing date code of the material
7.2.1.2 Environmental conditions where the material is stored
7.2.1.3 A digital photograph of the material showing the packing and storage
conditions.
7.2.1.4 In any case, the material is subject to all shelf life requirements as set forth
in this document. Including, but not limited to, moisture protection, proper
packing, solderability testing, etc.
7.2.1.5 Certificate of Authenticity with traceability back to the manufacturer. This
certificate should, among other things, stipulate:
7.2.1.5.1 Assurance that the factory boxes are sealed.
7.2.1.5.2 Assurance that the labels are consistent with the manufacturer
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7.2.2
and have no irregularities (misprinting, misalignment, altered
format, irregular manufacturer logos etc.)
7.2.1.5.3 Assurance that the product is closely inspected for: mixed date
codes, mixed lot codes, mixed country of origin, faint or faded
part markings, old, damaged or unclean parts, mixed production
dates, lead damage or irregularities
7.2.1.5.4 Assurance that the surface of parts not appear to have been redone. (Two-tone surface, painting or re-painting.), Wrong
package styles. (Example: parts should be TSOP but are SOIC)
and, mixed package styles. (Example: DIPs and SOIC)
7.2.1.5.5 Product conforms to and performs in accordance with the
specifications set forth by the OEM.
Document users outside of GE Power Electronics should contact their appropriate
supply management contact for guidance.
8. RETENTION OF COMPONENTS FOR LAST TIME BUY PRODUCT
8.1 SCOPE:
In certain circumstances, components must be retained for product no longer available from GE Power
Electronics. This section defines the storage and procurement process for this category of components.
8.2 PROCEDURE:
Upon Discontinued Availability (DA)/Last Time Buy status of a product, a material review should take
place for all stranded material.
All products purchased with the intent of storing beyond Shelf Life limits need to be tested for
Solderability (Dip and Look, Wetting Balance, and Steam Age) to extend solderability shelf life 6
months. Test is performed at the end of each shelf life period to extend solderability life.
8.3 COMPONENT REVIEW PROCESS
8.3.1 Review at time of Product discontinuance and Component Last Time Buy:
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Unit DA
Parts
available in
stock?
Stock to forecast
based on shelf life
Y
N
Are
components
available in
market?
Y
Buy reasonable
quantity based on
shelf life
N
Last time buy
possible?
Y
Arrange last time buy
based on shelf life
Y
Develop substitute and
procure
N
Substitute
component
possible?
N
Notify customer no
repair or support is
possible
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8.3.1 Review at time of Repair:
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Repair unit
received
Required
components in stock
meet shelf life
policy?
Y
Use for repair
N
Are
components
still available in
market?
Y
Buy reasonable
quantity based on
shelf life
N
Will customer accept reduced
warranty with “end of life”
components?
Y
Repair with
components
N
Review usages for
potential scrap
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Chapter 2
Printed Wiring Board Shelf Life
Storage & Baking
Old Matrix Document ID: MPS179000 ; Revision: 2.0
Release Date : 07/12/2007
TABLE OF CONTENTS
1.OBJECTIVE ............................................................................................................................................................................ 27
2.INTRODUCTION ................................................................................................................................................................... 27
3. STORAGE AMBIENT CONDITIONS ................................................................................................................................ 27
3.1 Packaging Bag ............................................................................................................................................... 28
4. DEPARTMENT RESPONSIBILITIES ............................................................................................................................... 28
4.1 Receiving Responsibilities ............................................................................................................................. 28
4.2 Incoming Responsibilities ............................................................................................................................. 29
4.3 Storage Location Responsibilities ................................................................................................................. 30
4.4 Manufacturing Responsibilities .................................................................................................................... 30
4.4.1 Baking Procedure ............................................................................................ 31
4.4.2 Solderability & Delamination Tests ................................................................. 31
5. SUMMARY ............................................................................................................................................................................ 32
5.1 Shelf Life Matrix ............................................................................................................................................ 32
5.2 Baking Time and Temperature ..................................................................................................................... 32
5.3 Reference Documents Specific to PCB.......................................................................................................... 32
5.4 Out Of Date PCB Revitalization Of PCB And Surface Finish .......................................................... 33
5.4. 1
Out Of Date PCB 6 Months to 20 Months .................................................................33
5.4.1
Out Of DATE PCB Over 20 Months .........................................................................33
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1 Objective
GE Power Electronics manufacturing is currently experiencing sporadic occurrences of Printed
Wiring Board (PWB) delamination. This document is intended to make engineering community aware of
affects of moisture on PWB delamination and provides recommendations on storage and baking to
minimize occurrence of these failures.
2 Introduction
PWB laminate material among other components consists of epoxy resin which is hygroscopic in
nature. The microscopic structure of the material has a strong capillary action that absorbs moisture from
the surrounding atmosphere. GE Power Electronics uses two kinds of laminate materials, viz., Dicycured and Non-Dicy cured. Dicy-cured materials by property absorb moisture much more readily than
the Non-Dicy cured materials.
Laminate materials in general quickly absorb moisture up to 0.08% to 0.1% by weight right after
processing. With prolonged storage, when moisture contents reach 0.18% to 0.20%, a vapor pressure of
8-10 bar is reached during reflow process, which leads to delamination. Target time for storing PWB’s
should be limited to moisture contents <0.14%, which typically means storage time no greater than six
months in vacuum sealed packaging at the recommended storage ambient conditions.
For technical assistance, contact GE Power Electronics Supplier Quality Reliability
Component Engineer Robert Roessler at 972-244-9369
The following are the recommendations on PWB storage and departmental responsibilities
for efficient PWB material management:
3 Storage Ambient Conditions
PWB`s should be stored in dry rooms. Constant low humidity is necessary until before the boards
are run through the reflow process. Laminate manufacturers and PWB manufacturers recommend storage
conditions at 23 °C (+/-2 °C) and < 60% RH. The boards must remain vacuum sealed in polyethylene
packages up until before use. Note that polyethylene bags allow diffusion and so do not provide complete
protection from moisture. These storage conditions apply to all PWB’s in inventory irrespective of the
type of surface finish (OSP, ENIG, & HASL) used.
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3.1 Packaging Bag:
Packaging Bag shall be a Moisture Barrier Bag. The Water Vapor Transmission Rate (WVTR) must
meet EIA 583 Class I, which has Maximum WVTR < or = 0.01g/100in2/24hr. The bag must meet the
requirements of Mil_PRF-81705, Type I for flexibility, ESD protection, mechanical strength and puncture
resistance. The puncture resistance of the bag must be greater than 15 pounds. The bag should be heat
sealable with the HIC card and Desiccant inside. The MBB shall be the Silver Aluminum Metallized Bag.
4 Department Responsibilities
4.1 Receiving Responsibilities:
GE Power Electronics incoming records the receive date of the PWB’s in SAP. A hard copy
containing received date and quantity per shipped box will be printed and attached to the packing slip of
each box. We will refer to this hard copy as “Age Sheet” going forward.
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4.2 Incoming Inspection Responsibilities:
GE Power Electronics incoming inspection will review the Certificate of Compliance (CoC)
information provided by the supplier and confirms “fit-to-use” after performing GE Power Electronics
standard First Article Inspection (FAI) procedures. At this stage, incoming will also inspect and verify
the following:
1. Condition of Packaging. Packaging shall not exhibit any damage such as tears and/or punctures.
Damaged Packaging - package is not Aluminum MBB and it has tear in corner
2. Humidity Exposure Levels on HIC card. HIC card must not indicate greater than 10% RH exposure.
Humidity Indicator Cards in Vacuum Sealed bags indicating < 50 % exposure
HIC at 40% Exposure
HIC at 50% Exposure
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3. Vacuum Seal and Desiccants: PWB’s received from suppliers shall be vacuum sealed with at least
two units of desiccants in each package.
4.3 Storage Location Responsibilities:
Silver Aluminum Metal Bag
Manufacturing order triggers material pull from storage. Storage personnel will pull quantity as needed
from the boxes based on FIFO (First-In First-Out) system. A copy of the “Age Sheet” will follow the
product to Manufacturing. Unused PWB`s must be vacuum sealed, packed, and stored in a controlled
environment immediately. SAP will be updated accordingly based on remaining material quantity in
storage. The “Age Sheet” will be manually updated and attached to the packing slip of the box to
reflect the quantity remaining in the box.
4.4 Manufacturing Responsibilities:
Manufacturing personnel will review the “Age Sheet” and determine if PWB’s need to be baked
prior to using them in production. Manufacturing personnel will bake the PWB’s if the receive date of the
PWB is greater than six months from the intended use date and the HIC card indicates greater than 10%
humidity exposure. The following are the recommendations for baking and the tests that follow
4.4.1 Baking Procedure
Baking of PWB’s is done to drive the moisture out from the laminate material. All GE Power
Electronics PWB’s have a solder resist coating on the surfaces (Solder Mask). The moisture ingress or
egress occurs from the sides where the laminate is exposed to surrounding environment. The baking time
is dependent on a number of factors, such as, number of layers in the board, inner layer copper layout
(design), board thickness and the type of laminate material used.
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In general, the following baking (drying) time and temperatures are recommended:
Drying Time (hrs)
4–8
8 – 10
10 – 12
18 – 20
Temperature (°C)
125
100
75
55
PWB panels in the baking oven must be horizontally stacked up to an inch height. The baked boards must
be used in assembly immediately afterwards. It is recommended that the boards be used within 48 hours
after baking to avoid the risk of moisture absorption and delamination.
Drying temperature and time are critical steps here and one must ensure the oven doors are not opened
intermittently while PWB’s are being baked. PWB’s must not be baked more than once in order not to
degrade surface finish and laminate material.
4.4.2 Solderability & Delamination Tests
These tests are left to the discretion of manufacturing supervisors.
It is recommended to use two samples of “baked” panels to perform the tests in order to establish
confidence in the product. One panel for Paste-Print and reflow test and the other for Solder Float
Delamination test.
1. “Paste-Print and Reflow” Solderability Test: The panel is paste printed on first side and then run
through reflow oven without placing any components. The panel at the end of the line is inspected for
consistent pad wetting. The process is repeated for the second side.
2. “Solder Float” Delamination Test: At least three circuits must be used for this test. The test needs to
be performed per test method IPC-TM-650 2.4.13.1. Dicy-cured laminate material must pass 3X solder
float at 288°C. While Non-Dicy cured material must pass 6X solder float at 288°C. Inspection for
delamination is visual and is usually seen as discoloration on the PWB surface. Note that paste-print
and reflow test also gives an opportunity to visually inspect for delamination.
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5 Summary
5.1 Shelf Life Matrix
PWB Shelf Life
Ambient Storage
Condition
PWB Finish Type
% RH
Electroless
Nickel/Immersion Gold
(ENIG)
[Lead or Lead free]
Hot Air Solder Level
(HASL)
< 60
23
12 Months
< 60
23
12 Months
< 60
23
6 Months
[Lead or Lead free]
Organic Solderability
Preservative (OSP)
Baking Required
After 6 Months?
PWB Shelf Life
°C
(+/- 2°C)
Yes
[If HIC indicates >10%
RH exposure. No baking
required if HIC < 10%]
Yes
[If HIC indicates >10%
RH exposure. No baking
required if HIC < 10%]
Yes
[If HIC indicates >10%
RH exposure]
5.2 Baking Time and Temperature
Drying Time
(hours)
4- 8
8- 10
10- 12
18- 20
Temperature
(°C)
125
100
75
55
Note:
• HIC indicator must read Less than 10% when opening the bag. Greater than 10% will require
Baking or return to PCB supplier
• MBB requirement is for Aluminium Metalized Bag
• WVTR is 0.01g/100in2/24hr
5.3 Reference Documents Specific TO PWB's
IPC-T-50
IPC-J-STD-003
IPC-J-STD-020
IPC-J-STD-033
IPC-SM-840
IPC-A-600
IPC-TM-650
Terms and Definitions
Solderability Test for PWB's
Moisture Sensitive Components
Packaging
Solder mask
Acceptability of Assembly Workmanship
Laboratory Test Methods, Solderability and Related Affects
-specifically IPC-TM-650 method 2.4.12 for solderability and 2.4.13.1 for stress
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IPC-6011
IPC-6012
(delam)
Generic Performance Specification of PWB's
Qualification and Performance of Rigid PWB's
5.4 Out of Date Revitalization of PCB and Surface Finish
5.4.1 PCB’s Out of Date between 6 Months and 20 Months
PCB’s that are out of Date/Shelf Life between 6 months and 20 months shall be tested for Moisture
Vulnerability, Lead Free Manufacturing Processability and Solderability Per PCB Out of Date Rework
Procedure titled PCB and Surface Finish Revitalization.
5.4.2 PCB’s Over 20 Months out of Date:
PCB’s that are over 20 months old are to be scrapped. To attempt to rework PCB’s that are over 20
months old increases risks in lead free manufacturing processes. This is due to the moisture absorbtion of
the material and the increased susceptibility to delamination during assembly of the PCB. Surface Mount
PCB’s receive a minimum of 2 lead free reflows and may undergo a third lead free reflow at the customer.
There is a high reliability risk in attempting to utilize present Lead Free materials in manufacturing and at
our customers.
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