IPC-TM-650 EN 2022 试验方法--.pdf - 第759页
5.2.2 Position the c oupons at each test head by at taching male to female connecto rs. 5.2.3 B aseline Performance (Optional) Establish a per- formance baseline by completing two Method A cycles and then stop the test a…
3.1 Coupon Design Rules
Certain designs rules must be
applied to achieve thermal uniformity. Electronic design files
for coupon construction are available from the equipment
supplier or printed board supplier. The resistance values (volt-
age drops) for each coupon are monitored independently for
each electrical net in test, using a four wire measurement
technique.
The test coupon(s) is incorporated on the panel to monitor or
qualify design, materials, or processes of product and/or reli-
ability assurance.
4 Apparatus or Material
At the time of publication of this
test method, 4.1 and 4.2 list the only known equipment
manufacturers of this test equipment. Equivalent test systems
may be used that operate on principles similar to those iden-
tified in Method A or B. IPC encourages their submission
along with relevant validation test data. This test method will
be revised as necessary to include these test systems as this
information becomes available.
Validation of this test method was performed with the equip-
ment listed in 4.1 and 4.2. Test conditions for the validation
are provided in 6.5. If alternate test equipment is used, valida-
tion in accordance with IPC-MDP-650 and 6.5 is recom-
mended.
4.1 Method A
4.1.1
This equipment is available from:
PWB Interconnect Solutions Inc. (Canada)
URL: www.pwbcorp.com
Equipment Type: IST
4.1.2
Two (2) four-pin, 2.54 mm [0.1 in] male connector
(ITW Pancon MFSS100-4-D or equivalent).
4.1.3
Sn60Pb40, Sn63Pb37, or lead free solder.
4.1.4
Solder flux.
4.1.5
Soldering iron.
4.2 Method B
4.2.1
This equipment is available from:
i3 Electronics (USA)
(formerly Endicott Interconnect Technologies)
URL: www.i3electronics.com
Equipment Type: CITC, CITC-TCR
4.2.2
4-wire multimeter, capable of measuring milliohms
4.2.3
Thermal imaging equipment – optional
5 Procedures
5.1 Sample Selection
5.1.1
Bench top measure the resistance of each net of the
coupon with a 4-wire multimeter. A net with an open cannot
be tested. A net with a short must be reworked to test the
coupon.
5.1.2 Coupon Selection
Select coupons for evaluation
based upon the test required as described in 5.1.2.1 through
5.1.2.3.
5.1.2.1 Random Sampling
A sample chosen without
regard to any characteristic of the individual coupons within a
population, within one or more lots.
5.1.2.2 Selective Sampling
A sample chosen based on
the resistance measurements of the sense and power nets.
Testing may include high, midrange and low resistance mea-
surements.
5.1.2.3 Comparative Sampling
A sample chosen based
on the resistance measurements of the sense and power
nets. Testing should include similar resistance measurements
for the populations being tested.
5.2 Method A Procedure
5.2.1 Single Sense Testing
Solder two four-pin male con-
nectors in the 1.02 mm [0.040 in] holes at the left and right
edges of the coupon (see Figure 3-1). A solder fillet must be
apparent on both sides of the coupon.
5.2.1.1 Dual Sense Testing (Optional)
When Dual Sense
Testing is required, solder three four-pin male connectors in
the 1.02 mm [0.040 in] holes at the edges of the coupon (see
Figure 5-1). A solder fillet must be apparent on both sides of
the coupon.
Dual Sense coupons may be tested using the Single
Sense Testing method.
Number
2.6.26
Subject
DC Current Induced Thermal Cycling Test
Date
5/14
Revision
A
IPC-TM-650
NOTE:
Page
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5.2.2
Position the coupons at each test head by attaching
male to female connectors.
5.2.3 Baseline Performance (Optional)
Establish a per-
formance baseline by completing two Method A cycles and
then stop the test at the end of the cooling cycle.
5.2.4 Capacitance Test (Optional)
If required, the capaci-
tance test
be performed per IPC-TM-650, Method
2.5.35.
5.2.5 Assembly Precondition (Optional)
Assembly pre-
conditioning is recommended to simulate the assembly envi-
ronment to which the printed boards are exposed (see 6.1).
5.2.6
Unless otherwise specified by the user, test all via
types and materials per the default test condition in accor-
dance with Table 5-1. For testing of samples containing
microvia structures, use the microvia test condition. For test-
ing of samples containing polyimide materials, use the polyim-
ide test condition.
5.2.7 Pre-Cycling Test Sequence
The following para-
graphs detail the sequence for a single coupon, however this
sequence is done at all test heads simultaneously. The ambi-
ent resistance, resistance at test temperature, rejection resis-
tance, and current are calculated for each coupon and dis-
played on the PC monitor.
IPC-2626-5-1
(Top-Down View as shown at left and Isometric View as shown at right)
Default 6 150 °C 10% 250 25 3 Calculated
Polyimide 6 AABUS 10% 250 25 3 Calculated
Microvias
2
6 190 °C 10% 250 25 3 None
Polyimide
Microvias
2
6 AABUS 10% 250 25 5 None
Survivability
Testing
6 230 °C 10% 10 1 5 None
6 245 °C 10% 10 1 5 None
6 260 °C 10% 10 1 5 None
For Dual Sense Testing, both the ‘‘Cycle Using’’ and the ‘‘Cycle Failing On’’ fields on the Method A test equipment be set to ‘both sense circuits.’
Power on the microvia or heating trace net.
Number
2.6.26
Subject
DC Current Induced Thermal Cycling Test
Date
5/14
Revision
A
IPC-TM-650
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Coupon
1
-P/S1/S2
Coupon
2
-
P/S1/S3
Coupon
3
-
P/S2/S3
Figure
5-1
Examples
of
Three
Dual
Sense
1ST
Test
Coupons
shall
Table
5-1
Method
A
Typical
Test
Conditions
Note
1.
Note
2.
Test
Condition
Number
of
Samples
Test
Temperatures
Failure
Threshold
(Resistance
Change)1
Number
of
Cycles
Data
Collection
Frequency
(Cycles)
Precycle
Time
Window
(seconds)
Compensation
0000c
-n
p-d
O0O0D
d
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5.2.7.1 Ambient Resistance
The auto ranging multimeter
measures the ambient resistance (voltage drop) of the net that
heats the coupon with DC current.
5.2.7.2 Resistance at Test Temperature
The system
software calculates and displays the resistance at the test
temperature. The available stress testing range is from 50 -
270 °C [122 - 518 °F]. The equation used to calculate the tar-
get resistance is as follows:
Target Resistance = Rrm x (1 + αT [Th - Trm])
where:
αT = Estimated thermal coefficient of resistance for the inter-
connect
Rrm = Resistance of coupon at ambient temperature
Th = Test temperature
Trm = Ambient Temperature (approximately 25 °C [77 °F])
5.2.7.3 Failure Threshold
The system software calculates
and displays the resistance change. This is adjustable from a
1% to a 100% increase. The typical failure threshold value is a
10% change in resistance. The equation to calculate the fail-
ure threshold is as follows:
Failure Threshold = (RT1 x Rr) + RT1
where:
Failure Threshold is in resistance
RT1 = Resistance of coupon at test temperature for Cycle 1
Rr = Resistance change (typically 10%)
5.2.7.4 Current
The system selects an initial current based
on the ambient resistance of the coupon and the current
table. The current tables are derived from software libraries on
the Method A test equipment. During the pre-cycling
sequence, the initial current is adjusted for each coupon to
assure the test temperature resistance is achieved in three
minutes ± precycle time window (see 5.2.7.5).
Additional equations/algorithms used by Method A
that establish the initial current selection for pre-cycling, rela-
tive to the relationship of coupon interconnect resistance αT,
coupon construction and stress test temperature to be
achieved are considered proprietary at this time.
5.2.7.5 Pre-Cycling
Pre-cycling is initiated by the applica-
tion of the selected current to the coupon; the computer
monitors the coupon’s performance throughout a 30 second
and 60 second cycle. The resistance level is monitored and
the current is adjusted based on the resistance reading.
These short duration tests adjust the current to prevent the
coupon heating rate being too fast on the first pre-cycle. The
computer monitors and records the coupon’s performance on
the first pre-cycle. If at the end of the first pre-cycle, the cou-
pon achieves the specified resistance level in three minutes ±
precycle time window, it will be accepted for subsequent
stress testing. If the resistance value was not achieved in this
time frame, the coupon will automatically be pre-cycled again
with a revised or compensated current. The system will retest
using revised conditions until all coupons are accepted or
rejected for stress testing.
The equation(s)/algorithms used by Method A to com-
pensate the DC current are considered proprietary at the time
of publication of this method revision.
5.2.7.6
Forced air cooling is commenced after each pre-
cycle to cool the coupons to ambient temperature.
5.2.7.7
The system automatically records and saves all
information regarding the pre-cycling conditions for subse-
quent stress testing.
5.2.8 Stress Cycle Test Sequence
The following para-
graphs detail the sequence for a single coupon; however this
sequence is done at all test heads simultaneously.
5.2.8.1
When the pre-cycle sequence is complete, the
Method A stress test is initiated by applying the same DC cur-
rent level established for each individual coupon during the
pre-cycle operation for three minutes. The computer monitors
and records the relative changes in resistance of the plated
barrel and internal connections throughout the heating cycle.
5.2.8.2
The three minutes of heating is followed by forced
air cooling. Cooling time is a function of overall thickness and
construction of the coupon. The computer monitors and
records the coupon’s performance throughout the cooling
cycle.
5.2.8.3
The individual coupons are placed on the tester and
are continually thermal cycled using their customized heating
and cooling conditions until the rejection criteria is achieved or
the maximum number of cycles is completed.
5.2.8.4
The coupon’s resistance ‘‘delta’’ (the variance from
resistance of coupon at test temperature for Cycle 2)
increases (positively) as failure inception occurs. The rate of
change in the delta is indicative of the mechanical change
(failure) within the barrel and/or internal connections.
Number
2.6.26
Subject
DC Current Induced Thermal Cycling Test
Date
5/14
Revision
A
IPC-TM-650
NOTE:
NOTE:
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