S2080 [TE]
Moisture Effects on the Soldering of Plastic Encapsulated Devices; 在塑料封装器件的焊接保湿效果
| 型号： | S2080 |
| 厂家： | 
TE CONNECTIVITY |
| 描述： | Moisture Effects on the Soldering of Plastic Encapsulated Devices |
| 文件： | 总2页 (文件大小：41K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Application Note
S2080
Moisture Effects on the Soldering of Plastic Encapsulated
Devices
Rev. V5
240°C, followed by
a
ramp-down back to room
Introduction
temperature. The lead-free/RoHS solder profile includes
a preheat to 200°C, followed by 60 - 150 seconds above
217°C with a maximum temperature of 260°C. Please
consult JEDEC for the complete profile.
Improper packaging, storage, and handling of plastic
encapsulated devices (PED’s) can trap moisture within
the devices and lead to damage during reflow soldering
to printed circuit boards. As part of reliability qualification
and testing, M/A-COM tests and classifies all
semiconductor devices for moisture sensitivity to assure
After the convection reflow procedure, we examine the
devices for failures. JEDEC defines moisture-induced
solder stress failures as any external cracks visible with a
40X optical microscope, DC electrical or functional
failures, and most internal cracks, especially those that
intersect a bond wire or ball/wedge bond. M/A-COM also
examines the devices for any delaminating associated
with moisture sensitivity.
long term reliability.
This application note briefly
describes the moisture-induced soldering failure
mechanism and test procedures, and moisture
sensitivities of M/A-COM’s plastic packaged
semiconductors.
Moisture Induced Soldering Failures
Moisture inside a plastic package turns to vapor and tries
to expand when the package is exposed to rapid high
M/A-COM performs these tests on any devices with
different package type, mold compound, or die pad area
relative to devices that we have already tested.
temperatures during soldering.
The internal vapor
pressure can cause separation of the plastic encapsulant
from the semiconductor chip or lead frame, internal and
external cracks, and damage to thin films and wire
bonds. In severe cases, soldering may cause an
integrated circuit to bulge and then explode with an
audible pop. Compared to through-hole devices, surface
mount devices (SMD’s) have thinner plastic capsules
and come into more intimate contact with high
temperatures. Therefore, measures to limit and reduce
the ingress of moisture during handling and storage of
SMD’s are generally more critical for SMD’s than for
through-hole devices. To reduce the effects of moisture-
induced stress during soldering, M/A-COM recommends
bake-out of some of its most moisture sensitive devices
before reflow soldering according to standard industry
procedures.
Moisture Absorption and Floor Life
After bake-out for removal of moisture, all PED’s
eventually reach a condition of humidity equilibrium
between the inside and outside of the package. JEDEC
defines the time at which the moisture inside the package
reaches a level likely to induce failure as the “floor life”.
The rate of moisture absorption depends upon ambient
temperature and humidity conditions, so JEDEC defines
the floor life under specific ambient conditions. Devices
stored beyond the floor life require a bake-out before
reflow soldering to avoid possible damage. M/A-COM
includes moisture sensitivity labels with all PED’s that
have a limited floor life and might need bake-out.
Moisture Sensitivity Ratings
Moisture Test Methods
Devices with sensitivity to moisture-induced solder stress
should be shipped and stored in sealed, dry containers
with a desiccant. As explained above, sensitive devices
require a bake-out to remove moisture prior to reflow
soldering if stored in typical ambient conditions beyond
the floor life, or damage could result.
M/A-COM tests its PED’s according to the procedures
outlined by the standards organization JEDEC. We will
briefly summarize the procedures here, but we
recommend that the reader consult IPC/JEDEC J-STD-
020, J-STD-033 and JESD22-A113 for detailed
explanation of test procedures and failure criteria. For
information on surface mounting consult application note
M538 or S2083.
Based on the floor life, JEDEC outlines six levels of
moisture sensitivity as shown in Table 1. Level 1 devices
are considered not sensitive to moisture, and have an
unlimited floor life. These devices do not require dry pack
shipping, and do not require bake-out prior to reflow
soldering. Devices above level 2 are considered moisture
sensitive, and require dry pack shipping and bake out.
Level 6 devices are considered extremely moisture
sensitive. The JEDEC guidelines specify that the user
should reduce or eliminate reflow heating by mounting
these PED’s on sockets or by performing a bake-out on
the devices immediately before reflow soldering.
As recommended by JEDEC, we start with a sample of
known good parts and subject the parts to a 24-hour
bake-out at 125°C to remove all moisture. Next we place
the parts in a moist, warm environment for a prescribed
period of time, as outlined in Table 1 under “soak
requirements”. Within four hours of removing them from
the soak, we then subject the parts to three cycles of
convection reflow with the temperature profile
recommended by JEDEC. The tin-lead eutectic solder
profile includes a preheat to 150°C, followed by 60 - 150
seconds above 180°C with a maximum temperature of
1
• North America Tel: 800.366.2266 • Europe Tel: +353.21.244.6400
Visit www.macomtech.com for additional data sheets and product information.
• India Tel: +91.80.4155721
• China Tel: +86.21.2407.1588
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
Application Note
S2080
Moisture Effects on the Soldering of Plastic Encapsulated
Devices
Rev. V5
Soak
Requirements
Conclusion
Level
Description
Floor Life
Moisture trapped inside plastic encapsulated devices
(PED’s) can damage them during soldering, as the
moisture vaporizes and tries to expand. M/A-COM tests
its PED’s for moisture sensitivity according to the
procedures outlined by the standards organization
JEDEC. With one exception at the time of wiring of this
application note, you can store any of M/A-COM PED’s
at room temperature and 85 percent relative humidity for
an unlimited time without experiencing solder damage
from moisture absorption. The exception in devices
packaged in the pBGA’s package, most of which we rate
at a moisture sensitivity level (MSL) of 3. M/A-COM
recommends that users of pBGA’s observe the JEDEC-
recommended cautions. If a user has stored these
devices beyond the floor life at or above recommended
temperature relative humidity, JEDEC guidelines
recommend a bake-out before reflow soldering.
Time
*
Hours
168
*
Unlim-
ited
1
2
Not Sensitive
1
3
Sensitive. Requires
dry pack
1 year
2
2
2
2
2
2
168
696
192
96
4
5
5
5
5
5
Sensitive. Requires
dry pack
4
2A
3
weeks
Sensitive. Requires
dry pack
168
hours
Sensitive. Requires
dry pack
72
hours
4
Sensitive. Requires
dry pack
48
hours
5
72
Sensitive. Requires
dry pack
24
hours
5A
48
Additional Notes:
Extremely Sensitive.
Dry pack. Socket
mount or bake-out
before reflow solder-
ing
1. See M/A-COM’s web site, www.macom.com, or
contact your local field sales representative, factory
applications engineer, or product manager for
assistance with moisture sensitivity and plastic
encapsulated semiconductor components. For
information on surface mounting consult application
note M538 or S2083.
See
Label
See
Label
6
2
5
*Conditions
1. ≤ 30°C / 85 percent relative humidity
2. ≤ 30°C / 60 percent relative humidity
3. 85°C / 85 percent relative humidity
4. 85°C / 60 percent relative humidity
5. 30°C / 60 percent relative humidity
(See test for definition of floor life.)
2. For more information on JEDEC procedures for
moisture sensitivity, see IPC/JEDEC J-STD-020,
J-STD-033 and JESD22-A113, available at
www.jedec.org
Table 1: JEDEC Defined Moisture Sensitivity
Level
Moisture Sensitivity Ratings of
M/A-COM Devices
All PED’s shown within the M/A-COM catalog meet
moisture sensitivity classification level 1, unless
otherwise indicated on the data sheet. At the time of
writing of this application note (November 2000), only
devices in plastic ball grid array (pBGA) packages, do
not meet level 1 specifications. M/A-COM rates these
devices at or above moisture sensitivity level 3,
indicating that the parts have a floor life of 168 hours or
less.
2
• North America Tel: 800.366.2266 • Europe Tel: +353.21.244.6400
Visit www.macomtech.com for additional data sheets and product information.
• India Tel: +91.80.4155721
• China Tel: +86.21.2407.1588
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
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