--------------------------------------------------- ------------------------ ---------------------
  ![](media/image1.png){width="2.265277777777778in"                            
  height="1.1409722222222223in"}                                               

  --------------------------------------------------- ------------------------ ---------------------

+--------+------------------------------------------+--------+--------+
|        | ***American Competitiveness Institute*** |        |        |
|        |                                          |        |        |
|        | JCAA/JG-PP LEAD-FREE SOLDER PROJECT      |        |        |
|        |                                          |        |        |
|        | NASA CONTRACT NO. NAS10-0329             |        |        |
|        |                                          |        |        |
|        | Final Report                             |        |        |
|        |                                          |        |        |
|        | **Mechanical Shock Environmental Testing |        |        |
|        | of Tin-Lead and Lead-Free Circuit        |        |        |
|        | Boards**                                 |        |        |
+--------+------------------------------------------+--------+--------+
|        |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| > **[  |                                          |        |        |
| DISTRI |                                          |        |        |
| BUTION |                                          |        |        |
| >      |                                          |        |        |
|  STATE |                                          |        |        |
| MENT:] |                                          |        |        |
| {.unde |                                          |        |        |
| rline} |                                          |        |        |
| >      |                                          |        |        |
| Distri |                                          |        |        |
| bution |                                          |        |        |
| > auth |                                          |        |        |
| orized |                                          |        |        |
| > to   |                                          |        |        |
| > U.S. |                                          |        |        |
| > Gove |                                          |        |        |
| rnment |                                          |        |        |
| > age  |                                          |        |        |
| ncies, |                                          |        |        |
| >      |                                          |        |        |
|  NASA, |                                          |        |        |
| > and  |                                          |        |        |
| > per  |                                          |        |        |
| sonnel |                                          |        |        |
| > who  |                                          |        |        |
| > have |                                          |        |        |
| >      |                                          |        |        |
| direct |                                          |        |        |
| >      |                                          |        |        |
|  invol |                                          |        |        |
| vement |                                          |        |        |
| > in   |                                          |        |        |
| > the  |                                          |        |        |
| > pr   |                                          |        |        |
| ogram. |                                          |        |        |
| >      |                                          |        |        |
|  Other |                                          |        |        |
| > re   |                                          |        |        |
| quests |                                          |        |        |
| > for  |                                          |        |        |
| > this |                                          |        |        |
| > do   |                                          |        |        |
| cument |                                          |        |        |
| >      |                                          |        |        |
|  shall |                                          |        |        |
| > be   |                                          |        |        |
| > re   |                                          |        |        |
| ferred |                                          |        |        |
| > to   |                                          |        |        |
| >      |                                          |        |        |
|  NASA. |                                          |        |        |
| > WA   |                                          |        |        |
| RNING: |                                          |        |        |
| > Co   |                                          |        |        |
| ntents |                                          |        |        |
| > are  |                                          |        |        |
| > not  |                                          |        |        |
| > cons |                                          |        |        |
| idered |                                          |        |        |
| > C    |                                          |        |        |
| ompany |                                          |        |        |
| >      |                                          |        |        |
|  propr |                                          |        |        |
| ietary |                                          |        |        |
| > and  |                                          |        |        |
| > is   |                                          |        |        |
| > ap   |                                          |        |        |
| proved |                                          |        |        |
| > for  |                                          |        |        |
| >      |                                          |        |        |
| public |                                          |        |        |
| > rel  |                                          |        |        |
| ease** |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| SUB    |                                          |        |        |
| MITTED |                                          |        |        |
| TO:    |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| Kurt   |                                          |        |        |
| K      |                                          |        |        |
| essel, |                                          |        |        |
| P      |                                          |        |        |
| roject |                                          |        |        |
| Inte   |                                          |        |        |
| grator |                                          |        |        |
|        |                                          |        |        |
| <Kur   |                                          |        |        |
| t.Kess |                                          |        |        |
| el-1@k |                                          |        |        |
| sc.nas |                                          |        |        |
| a.gov> |                                          |        |        |
|        |                                          |        |        |
| *      |                                          |        |        |
| *Joint |                                          |        |        |
| C      |                                          |        |        |
| ouncil |                                          |        |        |
| on     |                                          |        |        |
| Aging  |                                          |        |        |
| Airc   |                                          |        |        |
| raft** |                                          |        |        |
|        |                                          |        |        |
| *      |                                          |        |        |
| *Joint |                                          |        |        |
| Group  |                                          |        |        |
| on     |                                          |        |        |
| Pol    |                                          |        |        |
| lution |                                          |        |        |
| Preven |                                          |        |        |
| tion** |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| NASA   |                                          |        |        |
| --     |                                          |        |        |
| John   |                                          |        |        |
| F.     |                                          |        |        |
| K      |                                          |        |        |
| ennedy |                                          |        |        |
| Space  |                                          |        |        |
| Center |                                          |        |        |
+--------+------------------------------------------+--------+--------+
|        |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| SUB    |                                          |        |        |
| MITTED |                                          |        |        |
| BY:    |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| AM     |                                          |        |        |
| ERICAN |                                          |        |        |
| COM    |                                          |        |        |
| PETITI |                                          |        |        |
| VENESS |                                          |        |        |
| INS    |                                          |        |        |
| TITUTE |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| One    |                                          |        |        |
| I      |                                          |        |        |
| nterna |                                          |        |        |
| tional |                                          |        |        |
| Plaza  |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| P      |                                          |        |        |
| hilade |                                          |        |        |
| lphia, |                                          |        |        |
| Pennsy |                                          |        |        |
| lvania |                                          |        |        |
+--------+------------------------------------------+--------+--------+
|        |                                          |        |        |
+--------+------------------------------------------+--------+--------+
|        |                                          |        |        |
+--------+------------------------------------------+--------+--------+
| No     |                                          |        |        |
| vember |                                          |        |        |
| 13,    |                                          |        |        |
| 2023   |                                          |        |        |
+--------+------------------------------------------+--------+--------+
|        |                                          |        |        |
+--------+------------------------------------------+--------+--------+

+--------+---------------------------------------------------+--------+
|        | ***American Competitiveness Institute***          |        |
|        |                                                   |        |
|        | Final Report                                      |        |
|        |                                                   |        |
|        | **Mechanical Shock Environmental Testing of       |        |
|        | Tin-Lead and Lead-Free Circuit Boards**           |        |
|        |                                                   |        |
|        | CONTRACT NO. N00014-01-C-0050                     |        |
+--------+---------------------------------------------------+--------+

**Abstract**

The American Competitiveness Institute (ACI) performed a series of
Environmental Stress Tests for the Joint Council of Aging Aircraft /
Joint Group of Pollution Prevention ( JCAA / JG-PP) Lead Free Soldering
Program. The objective was to determine if Lead Free soldered hardware
was equivalent to or better than its Tin lead (SnPb) counterpart. The
program's test vehicle was manufactured by BAE Systems in Irving, Texas.
The JCAA / JG-PP test vehicle was soldered with Tin lead (SnPb) as a
baseline, Tin silver copper (95.5Sn3.9Ag0.6Cu , also known as SAC solder
alloy), tin silver copper bismuth ((92.3Sn3.4Ag1.0Cu3.3Bi , also known
as SACB), and stabilized tin copper (99.3Sn0.7Cu0.05Ni also known as
SNiC solder alloy).

Two types of Mechanical Shock tests were performed. The first Mechanical
Shock test was performed using the test procedure MIL-STD 810F; Method
516.5; Procedure 1. This is the "Crash Hazard Test" for the flight
equipment. The test was performed on all 3 axes. Two components soldered
with SACB failed during the tests. The balance of the SnPb and Lead Free
soldered components passed this mechanical shock test with no failures.

The second Mechanical Shock test was performed to a modified version of
MIL-STD 810F; Method 516.5; Procedure 1, where the test vehicle was
tested in the Z-Direction only, at increasing levels of snock to
failure. The mechanical shock levels reached in this test were well
above those in the first mechanical shock test. Most assemblies survived
the first 300 shocks of these higher levels up to level 2.3 (75 g level)
without experiencing any significant number of failures. These results
are reported here. At the dramatically increased levels of shock (\>100
g) failures of the copper traces of the test multilayer board and
perhaps the connectors on the test vehicle masked any further failures
of either the lead-free or tin-lead soldered hardware, and therefore did
not yield credible results for either the lead-free or tin-lead soldered
samples. Across all test levels and component types, where results
couild be interpreted, the SnPb soldered hardware performed comparably
to or better than the SAC and the SACB soldered hardware.

Post test data analysis indicates that the failures recorded above the
purposely excessive shock levels graeater than approximately 100 g were
not solder joint failures, but test vehicle and/or measurement equipment
failures.

Based on limited FMA conducted at the ACI, we have determined that the
BGA devices indicating failures in the extremely high g (above 75g)
shock tests, did not fail in the solder joints. The few noted BGA
failures, even in the ultra high g shocks applied, were determined to be
copper trace failures in the multilayer board substrate to which the
BGAs were mounted, at the trace-BGA land neck area. These failures of
the test vehicle board traces, perhaps in combination with connector
intermittent failures, at the high g shock levels, make any results for
the extremely high g shocks (greater than 75 g) suspect, and so are not
reported here. The only conclusion that can be made for these high shock
values regarding tin-lead vs. lead-free solder systems, is that neither
system failed in the solder joints Because of circuit board and/or
connector failures at the extremely high g shock levels no further
conclusions are possible.

**Table of Contents**

Abstract 4

List of Tables 6

List of Figures 7

Acronyms 8

[Summary 10](#__RefHeading___Toc130707033)

[1 Mechanical Shock Tests 11](#mechanical-shock-tests)

[Mechanical Shock Test 1 - Test Procedure
12](#mechanical-shock-test-procedure-1---test-procedure)

[Mechanical Shock Test 1-Test Results
15](#mechanical-shock-test-1-test-results)

[Mechanical Shock Test 1-Failure Analysis
16](#mechanical-shock-test-1-failure-analysis)

[2 Mechanical Shock Test 2 19](#mechanical-shock-test-2)

[Test Procedure 19](#test-procedure)

[Mechanical Shock Test 2 -Test Results
24](#mechanical-shock-test-2--test-results)

[2.2.1 Component TSOP-50 25](#__RefHeading___Toc130707041)

[2.2.2 Component TQFP -- 144 26](#__RefHeading___Toc130707042)

[2.2.3 Component TQFP -- 208 27](#__RefHeading___Toc130707043)

[2.2.4 Component PLCC -- 20 28](#__RefHeading___Toc130707044)

[2.2.5 Component PDIP -- 20 29](#__RefHeading___Toc130707045)

[2.2.6 Component BGA -- 225 30](#__RefHeading___Toc130707046)

[2.2.7 Component CLCC -- 20 31](#__RefHeading___Toc130707047)

[3 Mechanical Shock Test Failure Mode Analysis
32](#mechanical-shock-test-failure-mode-analysis)

[Mechanical Shock Test -- Procedure
32](#mechanical-shock-test-procedure)

[Failure Analysis 33](#failure-analysis)

[Test Procedure Critical Review 38](#test-procedure-critical-review)

[Test Observations 40](#__RefHeading___Toc130707052)

[4 Chemical Analysis of Solder Alloys
41](#chemical-analysis-of-solder-alloys)

[Test Methods: 41](#test-methods)

[Results: 41](#results)

[5 Discussion 42](#discussion)

[6 Conclusions 47](#conclusions)

[Mechanical Shock Test-I 47](#mechanical-shock-test-procedure-1)

[Mechanical Shock Test-II 47](#__RefHeading___Toc130707059)

[7 Acknowledgements 49](#acknowledgements)

[8 Appendices 50](#appendices)

[Appendix A: Mechanical Shock Testing Procedure
51](#appendix-a-mechanical-shock-testing-procedure)

[Raw Test Data Mechanical Shock Test Level 2: Board 28
1](#__RefHeading___Toc130707066)

[Raw Test Data Mechanical Shock Test Level 2: Board 29
2](#__RefHeading___Toc130707067)

[Raw Test Data Mechanical Shock Test Level 2: Board 64
3](#__RefHeading___Toc130707068)

[Raw Test Data Mechanical Shock Test Level 2: Board 65
4](#__RefHeading___Toc130707069)

[Raw Test Data Mechanical Shock Test Level 2: Board 97
5](#__RefHeading___Toc130707070)

[Raw Test Data Mechanical Shock Test Level 2: Board 98
6](#__RefHeading___Toc130707071)

[Raw Test Data Mechanical Shock Test Level 2: Board 170
7](#__RefHeading___Toc130707072)

[Raw Test Data Mechanical Shock Test Level 2: Board 171
8](#__RefHeading___Toc130707073)

[Raw Test Data Mechanical Shock Test Level 2: Board 136
9](#__RefHeading___Toc130707074)

[Raw Test Data Mechanical Shock Test Level 2: Board 137
10](#__RefHeading___Toc130707075)

[Raw Test Data Mechanical Shock Test Level 2: Board 198
11](#__RefHeading___Toc130707076)

[Raw Test Data Mechanical Shock Test Level 2: Board 199
12](#__RefHeading___Toc130707077)

**List Of Tables**

[**Table 1**: Mechanical Shock I Testing Level
12](#__RefHeading___Toc130698772)

[**Table 2**: Mechanical Shock II Testing Levels
19](#__RefHeading___Toc130698773)

[**Table 3**: TSOP-50 Failure Data 25](#__RefHeading___Toc130698774)

[**Table 4**: TQFP -- 144 Failure Data 26](#__RefHeading___Toc130698775)

[**Table 5**: TQFP-208 Data 27](#__RefHeading___Toc130698776)

[**Table 6**: PLCC-20 Failure Data 28](#__RefHeading___Toc130698777)

[**Table 7**: PDIP-20 Failure Data 29](#__RefHeading___Toc130698778)

[**Table 8**: BGA-225 Failure Data 30](#__RefHeading___Toc130698779)

[**Table 9**: CLCC-20 Failure Data 31](#__RefHeading___Toc130698780)

[**Table 11:** EDX Chemical Analysis Results (weight %)
41](#__RefHeading___Toc130698781)

**List Of Figures**

[**Figure 1:** JCAA / JG-PP Test Vehicle Mounted On Vibration Table
12](#__RefHeading___Toc130892135)

[**Figure 2:** Test Level 1.1 Power Spectrum Density Graph
13](#__RefHeading___Toc130892136)

[**Figure 3:** Test Level 1.2 Power Spectrum Density Graph
13](#__RefHeading___Toc130892137)

[**Figure 4:** Test Level 1.3 Power Spectrum Density Graph
14](#__RefHeading___Toc130892138)

[**Figure 5:** Test Level 1.4 Power Spectrum Density Graph
14](#__RefHeading___Toc130892139)

[**Figure 6:** Mechanical Shock Test 1 Test Results
15](#__RefHeading___Toc130892140)

[**Figure 7:** Board 135, U3, TQFP-208 has continuity around the
component, both top and bottom side 16](#__RefHeading___Toc130892141)

[**Figure 8**: Board 135, U3, TQFP-208 has sufficient toe solder and
heel solder and typical solder joints. 16](#__RefHeading___Toc130892142)

[**Figure 9**: Board 135, U62, TSOP-50 rings out from test point to
adjacent pins, but not to opposite pins (top), out from adjacent test
point to adjacent pins but not from row to row (bottom).
17](#__RefHeading___Toc130892143)

[**Figure 10:** X-ray inspection did not show any internal defects
17](#__RefHeading___Toc130892144)

[**Figure 11:** Pseudo-microsection showing separation on end gull wing
lead 18](#__RefHeading___Toc130892145)

[**Figure 12:** Microsection showing complete separation of solder
joint, confirming
18](#figure-12.-microsection-showing-complete-separation-of-solder-joint-confirming)

[**Figure 13**: SEM Micrograph does not show distinct intermetallic
growth. 18](#__RefHeading___Toc130892147)

[**Figure 14:** Test Level 2.1 Power Spectrum Density Graph
20](#__RefHeading___Toc130892148)

[**Figure 15:** Test Level 2.2 Power Spectrum Density Graph
20](#__RefHeading___Toc130892149)

[**Figure 16:** Test Level 2.3 Power Spectrum Density Graph
21](#__RefHeading___Toc130892150)

[**Figure 17**: Test Level 2.4 Power Spectrum Density Graph
21](#__RefHeading___Toc130892151)

[**Figure 18**: Test Level 2.5 Power Spectrum Density Graph
22](#__RefHeading___Toc130892152)

[**Figure 19:** Test Level 2.6 Power Spectrum Density Graph
22](#__RefHeading___Toc130892153)

[**Figure 20:** Test Level 2.7 Power Spectrum Density Graph
23](#__RefHeading___Toc130892154)

[**Figure 21**: Dye-N-Pry Process: Board 97, SnAgCu/SnAgCu, BGA U6, PCB
trace failure at BGA Ball 15R. Land Pads lifted cleanly, separating at
the conductor to land pad interface indicating a cracked conductor. The
area of separation was also oxidized. 34](#__RefHeading___Toc130892162)

[**Figure 22**: Dye-N-Pry Process: Board 97, SnAgCu/Sn/AgCu, BGA U6, PCB
trace failures in the corner of the BGA. Land Pads lifted cleanly,
separating at the conductor to land pad interfaces indicating a cracked
conductors. The area of separation was also oxidized
34](#__RefHeading___Toc130892163)

[**Figure 23**: Board 29, SnPb MANUFACTURED, BGA U44, Solder Ball crack
on the Component side, No failures of this type found but small amount
of cracking seen. 35](#__RefHeading___Toc130892164)

[**Figure 24**: Board 29, SnPb MANUFACTURED, BGA U44, PCB trace failure
at BGA Ball 1R. 35](#__RefHeading___Toc130892165)

[**Figure 25**: Board 97, SnAgCu/SnAgCu, BGA U44, PCB trace failure at
BGA Ball 1R 36](#__RefHeading___Toc130892166)

[**Figure 26** : Board 97, SnAgCu/SnAgCu, BGA U44, PCB trace failure at
BGA Ball 2R. As can be seen this failure could cause intermittent
electrical failures. 36](#__RefHeading___Toc130892167)

[**Figure 27**: Board 97, SnAgCu/SnAgCu, BGA U44, PCB trace failure at
BGA Ball 1B. As can be seen this failure could cause intermittent
electrical failures 37](#__RefHeading___Toc130892168)

[**Figure 28**: Board 97, SnAgCu/SnAgCu, BGA U44, Solder ball crack on
component side, no failures found but small amount of cracking seen.
37](#_Ref130706463)

[**Figure 29**: Board 29, SnPb MANUFACTURED, BGA U44, PCB trace failure
at BGA Ball 1R, illustrating a complete failure
44](#__RefHeading___Toc130892170)

[**Figure 30**: Board 97, SnAgCu/SnAgCu, BGA U44, PCB trace failure at
BGA Ball 1B. As can be seen this failure could cause intermittent
electrical failures. 44](#__RefHeading___Toc130892171)

[**Figure 31**: Example of PCB Trace failures in the corner of the BGA.
Land Pads lifted cleanly, separating at the conductor to land pad
interfaces indicating a cracked conductors. The area of separation was
oxidized 45](#__RefHeading___Toc130892172)

[**Figure 32**: Example of Solder Ball cracked on the component side. No
failures of this type found but small amount of cracking seen
45](#__RefHeading___Toc130892173)

[**Figure 33: Test Fixture** 55](#__RefHeading___Toc130892174)

**LIST OF ACRONYMS**

  ---------- ----------------------------- -- ------ -- -------------------- ---
  ACI        American Competitiveness         SnCu      Tin-Copper Alloy     
             Institute                                  Solder               

  Ag         Silver                           SnPb      Tin lead Solder      

  Au         Gold                             T~g~      Glass Transition     
                                                        Temperature          

  AuPdNi     Gold-Palladium-Nickel            TQFP      Thin Quad Flat Pack  

  Bi         Bismuth                          TSOP      Thin Small Outline   
                                                        Package              

  CLCC       Ceramic Leaded Chip Carrier                                     

  Cu         Copper                                                          

  DoD        Department of Defense                                           

  EPA        Environmental Protection                                        
             Agency                                                          

  I/O        Input/Output                                                    

  JCAA       Joint Council on Aging                                          
             Aircraft.                                                       

  JG-PP      Joint Group on Pollution                                        
             Prevention                                                      

  JTP        Joint Test Protocol                                             

  JTR        Joint Test Report                                               

  NASA       National Aeronautical and                                       
             Space Administration                                            

  Ni         Nickel                                                          

  OSP        Organic Solderability                                           
             Preservative                                                    

  Pd         Palladium                                                       

  PDIP       Plastic Dual-Inline Package                                     

  PLCC       Plastic Leaded Chip Carrier                                     

  PTH        Plated-Through Hole                                             

  RoHS       Reduction Of Hazardous                                          
             Substance                                                       

  SAC        tin-silver-copper solder                                        
             alloy                                                           

  SACB       tin-silver-copper-bismuth                                       
             solder alloy                                                    

  Sn         tin                                                             

  SnAgCu     tin silver copper solder                                        
             alloy                                                           

  SnAgCuBi   tin silver copper bismuth                                       
             solder alloy                                                    
  ---------- ----------------------------- -- ------ -- -------------------- ---

# Summary {#summary .unnumbered}

Based on the components and boards which have undergone Mechanical Shock
testing, the tin-lead (SnPb) solder joints, the tin silver copper
(SnAgCuBi - SAC) solder joints, and the tin silver copper bismuth
(SnAgCuBi - SACB) solder joints were not the root cause of any recorded
failure in mechanical shock. It was determined by failure analysis that
the few failures noted were caused by packaging or wiring defects, and
only at the extremely high mechanical shocks. Based on the mechanical
shock tests performed, the Tin silver copper (SnAgCu) Lead Free solder
joints and the Tin silver copper bismuth (SnAgCuBi - SACB) solder joints
reliability were equivalent to Tin lead (SnPb) solder joints.

In the first Mechanical Shock Test, the Tin lead (SnPb) and Tin silver
copper (SnAgCu - SAC) soldered assemblies passed the environmental
stress screening testing described in MIL-STD 810F; Method 516.5;
Procedure 1. The Tin silver copper bismuth (SnAgCuBi - SACB) soldered
assemblies had three (3) TQFP-208 components and one (1) TSOP-50
component which failed, but failure analysis revealed that none of these
were solder joint failures, but workmanship or component defects.

In the second Mechanical Shock Test, at the lower levels of shock (\<
100 G Peak) the Tin lead (SnPb) performed slightly better than the Lead
Free Tin silver copper (SnAgCu - SAC) and the Tin silver copper bismuth
(SnAgCuBi - SACB) soldered assemblies. At the higher mechanical shock
test levels (\> 100 G Peak), Tin lead (SnPb) performed better than the
Lead Free Tin silver copper (SnAgCu - SAC) and the Tin silver copper
bismuth (SnAgCuBi - SACB) soldered assemblies. This difference is
minimal and dependent upon the type of electronic package used.

Based on very limited FA (Failure Analysis) conducted at the ACI, we
have determined that the few BGA devices that indicated failures in the
high g shocks of shock test 2, did not fail in the solder joints at all.
The few failures noted were determined to be copper trace failures, at
the trace-BGA land neck area.

# Mechanical Shock Tests 

The ACI Mechanical Shock Tests utilized a Ling Electronics B335
Vibration Systems at BAE Systems in Lansdale, Pennsylvania. A detailed
description of the test procedure is listed in the Appendix A.

ACI executed two separate Mechanical Shock tests for the program.

The first test was based on strict adherence to MIL-STD 810F; Method
516.5; Procedure 1, which is typically used for hardware certification
for ground based and flight based hardware at four levels of shock. As
required by this standard, shocks were applied in all three primary axes
for this first test.

The second test was a modified version of MIL-STD 810F; Method 516.5;
Procedure 1, in which the intention of JG-PP was to test the boards at
increasing levels of shock until the solder joints of all the components
on the PWAs failed. It was judged by the JG-PP committee that these
extreme shocks be administered in the Z-axis only.

Unfortunately, at high levels of shock in this second shock testing
progression, the copper traces on the substrate multilayer board and/or
the connectors linking the assembled components to the test equipment
failed before the solder joints failed. Only short, incomplete cracks in
the solder joints of the components, much smaller than would cause
solder joint failure, were detectable in FA (failure analysis). The only
complete fractures visible in FA cross sections of soder joints from the
second test were within the copper traces of the substrate multilayer
board.

Continuity testing was performed before and after each round of tests.
Any failure found was confirmed with the Anatech Event Detector. During
the test, all hardware was continuously monitored per IPC SM 785 and
IPC-9701 test standards. These standards require that electrical
interruption lasting greater than 0.2 µsec and continuity excursions
greater than 300 Ω, are considered failures when detected. During
testing, intermittent failures were found. We defined an intermittent
failure as a component/substrate daisy-chained circuit which showed a
failure using the event detector that could not be confirmed by manual
testing or that did not reappear at higher shock levels. The
daisy-chained component/substrate circuits showing intermittent failures
were identified, noting when these "failures" occurred during the tests.

First test failures were readily attributable to assembly and/or rework
workmanship effects not related to solder joint integrity for either the
lead-free or the tin-lead solder joints.

The second (progressively higher g) shock test, with the subsequent FA,
determined that the lead-free soldered assemblies performed similarly to
tin-lead (SnPb) soldered assemblies at extremely high shock stress
levels, up to the point where the copper traces of the substrate
multilayer board and/or the connectors linking the component/substrate
daisy-chains to the test equipment, failed. Both tin-lead and lead-free
joints survived these high levels of shock, but the board and/or
connectors did not.

## Mechanical Shock Test-Procedure 1 - Test Procedure {#mechanical-shock-test-procedure-1---test-procedure .unnumbered}

ACI performed the Mechanical Shock Tests for Shock Test 1 in the X, Y,
and Z axes. Table 1 illustrates the testing levels performed at each
step. Figure 1 demonstrates how the test vehicles were mounted on the
vibration table.

  ------------------------------------------------------ -----------------------------------------
  \\![](media/image2.png){width="3.0416666666666665in"   ![](media/image3.png){width="3.03125in"
  height="2.0104166666666665in"}                         height="2.0104166666666665in"}

  ------------------------------------------------------ -----------------------------------------

[]{#__RefHeading___Toc130892135 .anchor}**Figure 1:** JCAA / JG-PP Test
Vehicle Mounted On Vibration Table

Test Set One: 12 Boards

  ---------------------- ------------------------- ----------------------
  Test Vehicle Board     Manufactured With (Solder Reworked With (Solder
  Number                 Alloy)                    Alloy)

  62-63                  SnPb                      SnPb

  168-169                SnPb                      SnAgCu

  196-197                SnPb                      SnAgCuBi
  ---------------------- ------------------------- ----------------------

[]{#__RefHeading___Toc130698772 .anchor}**Table 1**: Mechanical Shock
Test-Procedure 1 Testing Level

![](media/image4.wmf){width="6.68125in" height="2.3069444444444445in"}

The following are examples of the Mechanical Shock Test-I Power Spectrum
Density graphs for Test Steps 1.1 through 1.4, illustrated in Figure 2
through Figure 5. The Mechanical Shock Test-I Power Spectrum Density
Graphs and Frequency Response Graphs for all three axes are located in
Appendix B.

![](media/image5.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892136 .anchor}**Figure 2:** Test Level 1.1
Power Spectrum Density Graph

![](media/image6.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892137 .anchor}**Figure 3:** Test Level 1.2
Power Spectrum Density Graph

![](media/image7.jpeg){width="5.0in" height="3.1944444444444446in"}

[]{#__RefHeading___Toc130892138 .anchor}**Figure 4:** Test Level 1.3
Power Spectrum Density Graph

![](media/image8.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892139 .anchor}**Figure 5:** Test Level 1.4
Power Spectrum Density Graph

## Mechanical Shock Test 1-Test Results {#mechanical-shock-test-1-test-results .unnumbered}

A total of 12 test vehicles were tested in Mechanical Shock Test 1 by
ACI. The Anatech event detector was reset after every change of shock
axis and after every level of shock applied.

ACI found no failures from any of the tin lead (SnPb) and SnAgCu
soldered hardware. (two vehicles each). However, three (3) TQFP-208
components and one (1) TSOP-50, either initially soldered or re-worked
with SACB, indicated failures in Mechanical Shock Test 1. Indicated
failures occurred during test step levels 1.1 and 1.2, as per Figure 6.
The three TQFP-208 devices exhibited intermitent electrical contacts at
Level 1.4 in the Y-axis. All failures indicated are 25% of a total of 4
such devices, two from vehicles originally manufactured using SACB
solder and two that had been initially manufactured with tin lead (SnPb)
solder, but reworked using SACB solder wire. Therefore all three of the
indicated failures from Test 1 are at the U3 location for the TQFP-208
devices, on the vehicles soldered or reworked with SACB only. This (U3)
position on the test vehicle board was prone to failure in many of the
other tests in the program (such as thermal cycle at Rockwell Collins
and vibration at Boeing), and appear to be a universal artifact of the
test vehicle, unrelated to the solder joint for these components.

The one failure (25% of four components) of the single TSOP-50 that
indicated failure on a single SACB soldered board, was once again an
artifact, as can be seen from the cross sections of the failure in
Figure 11, where the broken lead and excessively large solder joint
volume indicate poor workmanship rather than any solder joint property
as the root cause of the indicated failure.

  --------------------------------------- ------------------------------------------------------
  ![](media/image9.jpeg){width="3.0in"    ![](media/image10.jpeg){width="3.0104166666666665in"
  height="1.573611111111111in"}           height="1.5833333333333333in"}

  ![](media/image11.jpeg){width="3.0in"   ![](media/image12.jpeg){width="3.0in"
  height="1.573611111111111in"}           height="1.573611111111111in"}
  --------------------------------------- ------------------------------------------------------

[]{#__RefHeading___Toc130892140 .anchor}**Figure 6:** Mechanical Shock
Test 1 Test Results. Failures indicated are from a total of four (4)
components in each case.

## Mechanical Shock Test 1-Failure Analysis {#mechanical-shock-test-1-failure-analysis .unnumbered}

Visual inspection was conducted on all four Level 1 failures, as per
Table 2. Continuity tests were performed on all components to determine
continuity through the component without the effects of possible board
or connector failures.

**Table 2**. Mechanical Shock Test-I Component Failures

  ----------- -------------- --------------- ---------------- --------------
  **Board**   **Location**   **Component**   **Solder**       **Component
                                                              Finish**

  134         U3             TQFP-208        SACB             NiPdAu

  135         U3             TQFP-208        SACB             NiPdAu

  135         U62            TSOP-50         SACB             SnPb

  197         U3             TQFP-208        SACB (After      NiPdAu
                                             Rework)          
  ----------- -------------- --------------- ---------------- --------------

Each of the TQFPs indicating failure in Mechanical Shock Test 1 showed
electrical continuity. A photograph of such a TQFP device is shown in
**Figure 7.** These components had sufficient solder joints and toe and
heel fillets as shown in Figure 8. The three (3) TQFP-208 components
indicating failure somewhere in the daisy-chain circuit with the test
vehicle board all passed continuity testing on the substrate side, so it
is suspected that the solder joints all survived the test, and some
aspect of the test vehicle board might have caused the electrical
discontinuity that falsely indicated the failure. The root cause of
failure has not been identified, but is suspected to be related to the
Component U3 location on the test vehicle board, since components at the
U3 location unexpectedly failed other environmental stress screening
tests performed by the program at other program participant locations. .

![](media/image13.jpeg){width="2.65in" height="2.0in"}

[]{#__RefHeading___Toc130892141 .anchor}**Figure 7**. Board 135, U3,
TQFP-208 has continuity around the component, both top and bottom side

  ---------------------------------------- ----------------------------------------
  ![](media/image14.jpeg){width="2.65in"   ![](media/image15.jpeg){width="2.65in"
  height="2.0in"}                          height="2.0in"}

  []{#__RefHeading___Toc130892142          
  .anchor}**Figure 8**. Board 135, U3,     
  TQFP-208 has sufficient toe solder and   
  heel solder and typical solder joints.   
  ---------------------------------------- ----------------------------------------

The TSOP-50 component did not have electrical continuity from adjacent
rows of the TSOP connections. From the top side of the component, Figure
9, only one test point is available, as it is underneath the component.
From the bottom side of the component. The discontinuity still exists
between rows of TSOP pins. Within each row and its test point, however,
electrical continuity is present. X-Ray analysis did not find any
internal defects, as shown in Figure 10. Microsectioning discovered
separation of the end gull wing lead from its solder joint. The solder
wetted past the toe -- heel fillet, almost to the lead's knee, as
depicted in Figure 11 and Figure 12. This indicates excessive solder was
applied to the lead. This component was reworked with SACB solder in
production. SEM analysis showed a lack of intermetallic growth within
the solder joint, as shown in Figure 13.

  --------------------------------------- ---------------------------------------
  ![](media/image16.png){width="2.65in"   ![](media/image17.png){width="2.65in"
  height="1.9986111111111111in"}          height="1.9986111111111111in"}

  []{#__RefHeading___Toc130892143         
  .anchor}**Figure 9**. Board 135, U62,   
  TSOP-50 rings out from test point to    
  adjacent pins, but not to opposite pins 
  (top), out from adjacent test point to  
  adjacent pins but not from row to row   
  (bottom).                               
  --------------------------------------- ---------------------------------------

+-----------------------------------+-----------------------------------+
| ![](media/image18.j               | ![](media/image19.j               |
| peg){width="2.3229166666666665in" | peg){width="2.3229166666666665in" |
| height="1.9979166666666666in"}    | height="1.9979166666666666in"}    |
+-----------------------------------+-----------------------------------+
| []{#__RefHeading___Toc130892144   |                                   |
| .anchor}**Figure 10**. X-ray      |                                   |
| inspection did not show any       |                                   |
| internal defects                  |                                   |
|                                   |                                   |
| in the chip bonds (Board 135,     |                                   |
| U62, TSOP-50)                     |                                   |
+-----------------------------------+-----------------------------------+

+-----------------------------------+-----------------------------------+
| # ![](media/image20.jpeg){w       | # ![](media/image21.jpeg){wid     |
| idth="2.6666666666666665in" heigh | th="2.6666666666666665in" height= |
| t="2.0in"} {#section .unnumbered} | "2.0in"} {#section-1 .unnumbered} |
+-----------------------------------+-----------------------------------+
| []{#__RefHeading___Toc130892145   |                                   |
| .anchor}**Figure 11**.            |                                   |
| Pseudo-microsection showing       |                                   |
| separation on end gull wing lead  |                                   |
|                                   |                                   |
| left, and opposite solder joint   |                                   |
| (Board 135, U62, TSOP-50). This   |                                   |
| is a simple workmanship defect.   |                                   |
+-----------------------------------+-----------------------------------+

+-----------------------------------+-----------------------------------+
| # ![](media/image22.jpeg){wi      | # ![](media/image23.jpeg){wi      |
| dth="2.683333333333333in" height= | dth="2.683333333333333in" height= |
| "2.0in"} {#section-2 .unnumbered} | "2.0in"} {#section-3 .unnumbered} |
+-----------------------------------+-----------------------------------+
| # Figure 12                       |                                   |
| . Microsection showing complete s |                                   |
| eparation of solder joint, confir |                                   |
| ming  {#figure-12.-microsection-s |                                   |
| howing-complete-separation-of-sol |                                   |
| der-joint-confirming .unnumbered} |                                   |
|                                   |                                   |
| # the                             |                                   |
| continuity testing measurements ( |                                   |
| Board 135, U62, TSOP-50). {#the-c |                                   |
| ontinuity-testing-measurements-bo |                                   |
| ard-135-u62-tsop-50. .unnumbered} |                                   |
+-----------------------------------+-----------------------------------+

+-----------------------------------+-----------------------------------+
| # ![](media/image24.png){wid      | # ![](media/image25.png){wid      |
| th="2.5597222222222222in" height= | th="2.5597222222222222in" height= |
| "2.0in"} {#section-4 .unnumbered} | "2.0in"} {#section-5 .unnumbered} |
+-----------------------------------+-----------------------------------+
| []{#__RefHeading___Toc130892147   |                                   |
| .anchor}**Figure 13**. SEM        |                                   |
| Micrograph does not show distinct |                                   |
| intermetallic growth.             |                                   |
+-----------------------------------+-----------------------------------+

# Lack of intermetallic growth can be an indication of insufficient heat during soldering and perhaps incomplete wetting of the solder that could accompany this lack of intermetallic formation. All of these effects indicate the strong possibility that this one indicated failure may have been a workmanship issue rather than any indication of bulk solder fatigue or impact properties.  {#lack-of-intermetallic-growth-can-be-an-indication-of-insufficient-heat-during-soldering-and-perhaps-incomplete-wetting-of-the-solder-that-could-accompany-this-lack-of-intermetallic-formation.-all-of-these-effects-indicate-the-strong-possibility-that-this-one-indicated-failure-may-have-been-a-workmanship-issue-rather-than-any-indication-of-bulk-solder-fatigue-or-impact-properties. .unnumbered}

# 

# Mechanical Shock Test 2 

## Test Procedure {#test-procedure .unnumbered}

ACI performed the Mechanical Shock Tests in the Z axis only as agreed by
the entire JG-PP team. A total of twelve (12) test vehicle boards were
tested. Table 3 illustrates the testing levels performed at each step.

[]{#__RefHeading___Toc130698773 .anchor}**Table 3**: Mechanical Shock II
Testing Levels

![](media/image26.wmf){width="6.68125in" height="3.63125in"}

The following are examples of the Mechanical Shock Test-II Power
Spectrum Density graphs for Test Steps 2.1 through 2.7, as illustrated
in Figure 14 through Figure 20. All testing was performed in the Z-Axis
only as agreed by all team members. The Mechanical Shock Test 2 Power
Spectrum Density Graphs and Frequency Response Graphs for all three axes
are located in Appendix B.

![](media/image27.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892148 .anchor}**Figure 14:** Test Level 2.1
Power Spectrum Density Graph

![](media/image27.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892149 .anchor}**Figure 15:** Test Level 2.2
Power Spectrum Density Graph

![](media/image28.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892150 .anchor}**Figure 16:** Test Level 2.3
Power Spectrum Density Graph

[]{#__RefHeading___Toc130892151
.anchor}Pow![](media/image28.jpeg){width="5.0in"
height="3.4097222222222223in"}er Spectrum Density Graph

**Figure 17**: Test Level 2.4

![](media/image29.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892152 .anchor}**Figure 18**: Test Level 2.5
Power Spectrum Density Graph

![](media/image30.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892153 .anchor}**Figure 19:** Test Level 2.6
Power Spectrum Density Graph

![](media/image31.jpeg){width="5.0in" height="3.4097222222222223in"}

[]{#__RefHeading___Toc130892154 .anchor}**Figure 20:** Test Level 2.7
Power Spectrum Density Graph

## Mechanical Shock Test 2 -Test Results {#mechanical-shock-test-2--test-results .unnumbered}

At mechanical shock Test Level 2.1 (20 G Peak) through Test Level 2.3
(75 G Peak) there were random failures recorded by the test setup. The
Anatech event detector was reset after every shock level. Test Levels
2.1 thru 2.3 are equivalent to the Functional Test for Flight Equipment,
the Functional Test for Ground Equipment, and the Crash Hazard Test for
Flight Equipment. One hundred (100) shocks were imparted at each level
in the Z-axis only, as agreed with the JG-PP team members. This was a
more severe test than Mechanical Shock Test 1, where a total of 9 shocks
were imparted at each level, consisting of three (3) shocks imparted in
each axis.

At the higher Mechanical Shock Test 2 test levels, from Test Level 2.4
(100 G Peak) through Test Level 2.7 (500 G Peak), the test set-up
recorded numerous simultaneous failures of multiple devices with
intermittent contact. At Level 2.4 (\> 100 G Peak) and above, failure
event data again indicated numerous simultaneous failures that were
intermittent in nature. These intermittent failures, could be failures
of the multilayer interconnection board traces (some examples of which
are recorded in Failure Analysis section of this report) and/or the
electrical connectors in the circuit, and not the solder joint failures
intended to be detected, and so confound the test data and do not allow
clean interpretation of the test results for Test Procedure 2 shocks. An
intermittent contact/open appearing in these data may be the result of
several possibilities such as:

-   Shock failed solder/interconnect joints breaking and remaking
    electrical contact.

-   Failures not at the device level but somewhere else within the board
    interconnect chain, such as board traces fracturing. .

-   Failures within the component (i.e. wire bonds) but not within the
    solder/interconnect joint.

-   Failures at the mechanical connector.

The post-test data analysis indicated that the failures, which were
recorded past the level 2.3, contain, in addition to possible actual
solder joint failures, possible board level interconnect failures and
test set-up related failures such as connector failures. Since it was
determined that the data beyond test level 2.3 is confounded with
failures other than the DUT (Device Under Test), and since any shocks
over 50 g peak are above the maximum acceleration for the connector used
on the test vehicle, results of all shock tests in Test Procedure 2 are
compromised by board and/or connector failures. Appendix B shows the
entire test data in a raw format, which includes all indicated failures
(not necessarily DUT failures), experienced thru level 2.1 to 2.7. It
can be concluded from the numerous simultaneous intermittent failures
that the Test Procedure 2 data is compromised. This conclusion is
supported by the connector data sheet and the failure analysis showing
board copper trace failures

# Mechanical Shock Test Failure Mode Analysis

Limited scale failure mode analysis of failed solder joints was
conducted on the components/boards that had failed in mechanical shock
procedure 2 testing. The investigation included visual examination of
solder joints at 10-90X, followed by manual electrical continuity
testing of each daisy-chain net on each circuit board. Subsequently,
boards were subjected to X-ray inspection, and die penetrant testing
followed by micro sectioning and SEM examination of the failed
interconnect sites. Pinpointing a component level failure in the shock
tested boards presents a challenge, since the electrical probe testing,
does not lead to open circuit location. In our failure analysis, we
analyzed one board from each solder type and only BGA device failures
were evaluated.

## Mechanical Shock Test -- Procedure {#mechanical-shock-test-procedure .unnumbered}

Three boards from the lot of 12 boards in the level 2 mechanical shock
test were visually inspected for solder joint cracks after the
mechanical shock testing. One board from each solder type was selected
as described below:

Board \# 29 - SnPb manufactured,

Board \# 97 - SnAgCu/SnAgCu, and

Board \# 137- SnAgCuBi/SnCu.

No failures were visually identified at 10 -- 90X magnification, at this
stage. Then the boards were manually checked for electrical continuity
and failure locations were noted for the SnAgCu, SnAgCuBi and SnPb
boards. Electrical opens were identified and were tabulated. The
majority of the failures were located at the BGA devices in the SnAgCu
followed by the SnPb and the least number of failures were logged on the
SnAgCuBi board.

Subsequently, Board \# 29 (SnPb) and board \# 97 (SnAgCu/SnAgCu) were
soaked in a dye penetrant solution, using vacuum to work the dye into
any cracks. After baking the boards, a second visual inspection was
performed to see if the dye had highlighted any solder joints cracks.
Visual inspection showed highlighted cracks in the solder joints only at
the board connectors. Some of these cracks appear to be superficial and
may be acceptable to IPC specifications. Further investigation, which
should include cross sectioning and SEM inspection, is needed to verify
if these surface cracks penetrate the entire solder joint. Most of the
solder joints, with the visual cracks, do not test electrically open.
Since cracks caused by the mechanical shock are often very narrow and
the spring tension on the connector leads electrically closes the
circuit.

An additional three boards were temperature cycled from -55°C to 125°C,
for 10 cycles to attempt to permanently open intermittent electrical
failures on the boards. The cycle included 10-minute soak after reaching
each temperature. All three boards were continuously electrically
monitored to log any intermittent electrical failures, during the
temperature cycling. No additional or intermittent electrical failures
were recorded during or after temperature cycling on any of the boards.

## Failure Analysis  {#failure-analysis .unnumbered}

The failures underneath the BGA devices are not visible in the
microscopic examination. To assess the damage caused by the shock
testing, initially some of BGAs were pried from the boards to see if the
dye penetrate had highlighted the failure areas. After prying a BGA
device, the solder side of the BGA and the PCB solder areas were
inspected for the dried out dye in the failure areas. None of the BGA
solder ball failures or PCB failures, indicated the presence of the dye
penetrant. The only indications of failures were on the corner BGA
balls, where the metal lands had lifted without pulling up the
connecting conductor trace. At higher magnification, copper oxide was
noted on the edges, where the connecting conductor had separated. See
Figure 21 and Figure 22 for general indications of failures. Further
investigation correlated failures with electrical opens from the
electrical continuity test.

One additional BGA device was separated from both the SnPb and the
SnAgCu boards for cross sectioning. The devices were cross-sectioned,
lapped and polished to reveal the interconnecting solder balls at the
previously identified electrical continuity failure areas.

Electrical opens can be seen at high magnification, at the printed
circuit board land to connecting conductor trace. Failures were
identical in both the SnPb boards, as illustrated in Figure 24 and
SnAgCu boards -- Figure and Figure 26.

As can be seen in Figure 26 and Figure 27, some of these copper trace
opens will be intermittent failures during shock testing, since the
conductor is still in intimate contact with the land pad between shocks.

Some of the adjacent BGA balls exhibit partial cracking in the solder
joints as shown in Figure23 (SnPb) and Figure 28 (SnAgCu). However, no
complete solder joint crack failures were observed in any of the
cross-sections.

![](media/image32.jpeg){width="3.0in" height="2.6375in"}

[]{#__RefHeading___Toc130892162 .anchor}**Figure 21**: Dye-N-Pry
Process: Board 97, SnAgCu/SnAgCu, BGA U6, PCB trace failure at BGA Ball
15R. Land Pads lifted cleanly, separating at the conductor to land pad
interface indicating a cracked conductor. The area of separation was
also oxidized.

![](media/image33.jpeg){width="2.9833333333333334in" height="2.1375in"}

[]{#__RefHeading___Toc130892163 .anchor}**Figure 22**: Dye-N-Pry
Process: Board 97, SnAgCu/Sn/AgCu, BGA U6, PCB trace failures in the
corner of the BGA. Land Pads lifted cleanly, separating at the conductor
to land pad interfaces indicating a cracked conductors. The area of
separation was also oxidized

![](media/image34.png){width="4.616666666666666in" height="3.4625in"}

[]{#__RefHeading___Toc130892164 .anchor}**Figure 23**: Board 29, SnPb
MANUFACTURED, BGA U44, Solder Ball crack on the Component side, No
failures of this type found but small amount of cracking seen.

![](media/image35.jpeg){width="4.897916666666666in"
height="3.296527777777778in"}

[]{#__RefHeading___Toc130892165 .anchor}**Figure 24**: Broad 29, SnPb
MANUFACTURED, BGA U44, PCB trace failure at BGA Ball 1R.

![](media/image36.png){width="5.159027777777778in" height="4.125in"}

[]{#__RefHeading___Toc130892166 .anchor}**Figure 25**: Board 97,
SnAgCu/SnAgCu, BGA U44, PCB trace failure at BGA Ball 1R

![](media/image37.png){width="4.566666666666666in"
height="3.3777777777777778in"}

[]{#__RefHeading___Toc130892167 .anchor}**Figure 26** : Board 97,
SnAgCu/SnAgCu, BGA U44, PCB trace failure at BGA Ball 2R. As can be seen
this failure could cause intermittent electrical failures.

![](media/image38.png){width="5.533333333333333in" height="4.15in"}

[]{#__RefHeading___Toc130892168 .anchor}**Figure 27**: Board 97,
SnAgCu/SnAgCu, BGA U44, PCB trace failure at BGA Ball 1B. As can be seen
this failure could cause intermittent electrical failures

![](media/image39.jpeg){width="4.429861111111111in"
height="3.3229166666666665in"}

[]{#_Ref130706463 .anchor}**Figure 28**: Board 97, SnAgCu/SnAgCu, BGA
U44, Solder ball crack on component side, no failures found but small
amount of cracking seen.

##  {#section-7 .unnumbered}

##  {#section-8 .unnumbered}

##  {#section-9 .unnumbered}

## Test Procedure Critical Review  {#test-procedure-critical-review .unnumbered}

ACI performed an analysis of the Mechanical Shock Test-II Procedure to
determine the root cause of intermittent and inconsistent recorded
component failures. We evaluate 3 critical test areas which may have
contributed to the intermittent behaviour observed during the testing.

**Connector Selection**: Did the connector used in the test contribute
to false failures?

The following are the operating environmental specifications which the
connector is rated:

> Operating Temperature: -55°C to +125°C
>
> Shock: **50G peak** per MIL-STD-202, Method 213, Condition G
>
> Vibration: 12 cycles in three perpendicular directions @ 10-2000 Hz,
> per MIL-STD-202, Method 204, Condition D
>
> Moisture Resistance: 90-95% relative humidity @ 40°C for 96 hours per
> MIL-STD-202, Method 103

The Mechanical Shock Test-II has the following peak shocks shown in
Table 4

**Table 4**: Shock Test Level Parameters

+---+--------------------+------+-----+-----+-------+-------+-------+
| * | **Test Shock       | *    | **S | **P | *     | **Cr  | **Z-A |
| * | Response Spectra** | *Ini | lop | eak | *Ts** | oss-O | xis** |
| T |                    | tial | e** | G** |       | ver** |       |
| e |                    | G**  |     |     | **(   |       |       |
| s |                    |      |     |     | ms)** | **F   |       |
| t |                    |      |     |     |       | reque |       |
| * |                    |      |     |     |       | ncy** |       |
| * |                    |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Functional Test    | 4.5  | 6   | 20  | 15-23 | 45    | 100   |
| . | for Flight         |      |     |     |       |       |       |
| 1 | Equipment          |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Functional Test    | 8.5  | 6   | 40  | 15-23 | 45    | 100   |
| . | for Ground         |      |     |     |       |       |       |
| 2 | Equipment          |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Crash Hazard for   | 9    | 6   | 75  | 8-13  | 80    | 100   |
| . | Ground Equipment   |      |     |     |       |       |       |
| 3 |                    |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Level 1            | 12   | 6   | 100 | 15-23 | 80    | 100   |
| . |                    |      |     |     |       |       |       |
| 4 |                    |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Level 2            | 25   | 6   | 200 | 15-23 | 80    | 100   |
| . |                    |      |     |     |       |       |       |
| 5 |                    |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Level 3            | 35   | 6   | 300 | 15-23 | 80    | 100   |
| . |                    |      |     |     |       |       |       |
| 6 |                    |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Level 4            | 52   | 6   | 500 | 15-23 | 80    | 100   |
| , |                    |      |     |     |       |       |       |
| 7 |                    |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Level 5            | 72   | 6   | 700 | 15-23 | 80    | 100   |
| . |                    |      |     |     |       |       |       |
| 8 |                    |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+
| 2 | Level 6            | 90   | 6   | 1   | 15-23 | 80    | 100   |
| . |                    |      |     | 000 |       |       |       |
| 9 |                    |      |     |     |       |       |       |
+---+--------------------+------+-----+-----+-------+-------+-------+

Based on the connector specifications, we assessed that the connectors
survived the first three (3) tests levels. This is verified from the
data, where components in Mechanical Shock Test-I solder joints passed
the shock test. In Mechanical Shock Test-II, when the shock levels
constantly exceeded the 50G level, the connector contact failure
probably contributed to the intermittent contacts failures indicated
during the test.

**Lesson Learned**: All data collection wires should be soldered
directly into the test vehicle for the shock testing. Connectors should
not be used unless rated above the shock test levels.

**Wiring Selection**: Did the wire harness assembly used in the test
contribute to false failures?

The following are the operating environmental specifications which the
wiring is rated:

> Operating Temperature: -60^o^C to 200^o^C
>
> Voltage Rating: 600 V
>
> Conductor: Solid Silver Plated Copper
>
> Insulation: Extruded TFE Teflon

The wires used in the test were not shielded to prevent the potential
effects from Electromagnetic Interference (EMI). However, the test
contractor BAE Systems was unaware of any power line disturbances or
radiated EMI at that time. Their laboratory was equipped with power line
disturbance detection. No data was captured indicating that their
hardware operated outside of specifications.

**Lesson Learned**: As a precaution, all wires and cables connected to
the test vehicle should be shielded to prevent any false readings caused
by EMI.

**Equipment Grounding**: Was the test equipment fully grounded to
prevent potential Electrostatic Discharge (ESD) and EMI effects?

Prior to the test, ACI grounded the Anatech equipment at ACI's
facilities and at BAE Systems. The ground used was a system (electrical)
ground. The equipment was operating normally at both locations in set-up
trials prior to actual testing.

**Lesson Learned**: As a precaution, all hardware should be properly
grounded prior to performing test. It is recommended that earth ground
be used to ground the test equipment.[]{#__RefHeading___Toc130707052
.anchor}

Test Observations

The failures between Mechanical Shock Level 2.1 and Mechanical Shock
Level 2.3 are consistent between both Mechanical Shock Test Procedure 1
and Mechanical Shock Test Procedure 2. It was expected that Mechanical
Shock Test Procedure 2 would have more failures than the first test
since the test had inflicted more shocks in the Z-Axis.

Most of the failures (\> 90%) recorded during the Mechanical Shock
Procedure 2 occurred after Mechanical Shock Level 2.3.test. Beyond
Mechanical Shock test Level 2.3, the recorded open circuits and
intermittent failures can be attributed to one or more of multiple
factors listed below.

-   Connector Failures

-   Wiring Failures

-   Internal Component Damage

-   Board (Copper Trace) Damage

Therefore, rating the performance of the solder alloys tested beyond
Mechanical Shock Level 2.3 is not feasible.

# Chemical Analysis of Solder Alloys

To assess the compositional make-up of the repaired solder joints,
chemical analysis of repaired soldered assemblies was conducted. The
method used for analysis was Inductive Coupled Plasma method, which
provides a more accurate analysis of the solder composition.

## Test Methods: {#test-methods .unnumbered}

One JGPP fully populated and soldered assemblie was submitted for
analysis (Board 168) Samples of the solder were extracted with Pace
de-soldering station using new collection tubes and extraction tips
(Model number 1121-0625-P5). Approximately ½ gram of solder was removed
from the following location:

1.  SAC Rework Board 168 Component U18 BGA 225

Solder samples were analyzed using Energy Dispersive X-Ray (EDX) and
X-Ray Fluorescence (XRF) elemental analysis methods. The results are
shown in Error: Reference source not found.

## Results: {#results .unnumbered}

The results are shown in Table 11.

Table 11 EDAX Chemical analysis of solder joints of repaired Test
Vehicle Component shock tested.

<table style="width:100%;">
<colgroup>
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 12%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>TV</p>
<p>Board No.</p></td>
<td><p>Part</p>
<p>Type</p></td>
<td>Initial Board Finish</td>
<td><p>Initial Comp.</p>
<p>Finish</p></td>
<td><p>Solder</p>
<p>Used</p>
<p>for</p>
<p>Repair</p></td>
<td><p>Finish of</p>
<p>Repaired</p>
<p>Component</p></td>
<td><p>Tin</p>
<p>(wt. %)</p></td>
<td><p>Ag</p>
<p>(wt. %)</p></td>
<td><p>Cu</p>
<p>(wt. %)</p></td>
<td><p>Bi</p>
<p>(wt. %)</p></td>
<td><p>Pb</p>
<p>(wt. %)</p></td>
</tr>
<tr class="even">
<td>168</td>
<td><p>U18</p>
<p>BGA 225</p></td>
<td><p>HASL</p>
<p>SnPb</p></td>
<td>SnPb</td>
<td>Flux</td>
<td>SAC 405</td>
<td>94.34</td>
<td>4.11</td>
<td>0.38</td>
<td>0.00</td>
<td>1.17</td>
</tr>
</tbody>
</table>

These EDAX results were validated independently using X-Ray Fluorescence
(XRF).

# Discussion

At the mechanical shock Test Level 2.1 (20 G Peak) through Test Level
2.3 (75 G Peak) only few devices failed. Combined device failure data is
insufficient for all solder types, to draw any definitive conclusions
about relative performance of the solder types. Levels 2.1 to 2.3 are
consistent with the Functional Test for Flight Equipment levels, the
Functional Test for Ground Equipment levels, and the Crash Hazard Test
for Flight Equipment levels. 100 shocks were given at each level in the
Z-axis only. This was a more severe test than Mechanical Shock Test
Procedure 1, where only three (3) shocks were provided in each axis.
Based on this information, we can conclude that Lead-Free hardware
performed as well as tin-lead hardware, upto 75 G shock which is an
upper limit of the Crash Hazard Test for flight equipment. Even though
the connector is rated for use only up to 50 g, it apparently survived
through a few shocks at 75 g to allow these results.

At the higher Mechanical Shock Test Procedure 2 test levels, from Test
Level 2.4 (100 G Peak) through Test Level 2.7 (500 G Peak), the test
set-up recorded numerous simultaneous failures of multiple devices with
intermittent contacts. Post test analysis revealed that the failures
were within the test vehicle board and/or the connector/cable
interconnect chain, but the failures were not necessarily at solder
joints. Discontinuities within the electronic package and the hardware
instrumentation yielded the indicated failures, which could not be
distinguished from real solder joint failures. Failures in these cases
could be attributed to:

-   Electrical Interference

-   Board Level Failures

    -   Solder Joint Interconnect Failures

    -   Board Level Copper Wiring Failures

    -   Component Failures

-   Failures Associated With The Wiring Harness

-   Connector Failures

> [Electrical Interference]{.underline}: In conducting a review with BAE
> Systems, there were no detected power line disturbances or radiated
> EMI at that time of the test. BAE Systems have not experienced these
> types of failures since then. Therefore, this potential root cause of
> failure was eliminated.
>
> Real failures associated with the board level interconnect chain such
> as solder joints or PWB level copper wiring. For example board Damage
> would have resulted in a complete open or an intermittent failure
> within the daisy chain circuit. Similarly broken solder joint caused
> by a shock pulse, will show complete open or an intermitant contact.
>
> [Internal Component Damage]{.underline}: This would have resulted in a
> complete open failure of the daisy chain circuit. X-Ray analysis on
> specific failed components did not yield any evidence of failures.
> Therefore, this potential root cause of failure was eliminated.
>
> [Wiring Failures (external to PWB)]{.underline}: At the higher test
> levels, wiring failures would account for open circuits detected, but
> not for intermittent failures. Therefore, this potential root cause of
> failure was eliminated.
>
> [Connector Failures]{.underline}: In reviewing the connector's product
> data sheet, the connectors were rated for 50G peak per MIL-STD-202,
> Method 213; Condition G. This is below the 100G level at Test Level
> 2.4. It is speculated that an instantaneous open in the connector
> contact at the barrel contributed to the intermittent failures
> recorded during the higher shock level testing.

As a result, the majority of failures, recorded during the test level
2.4 to 2.7 are attributed to the high likelihood of mechanical connector
and/or board level failures. Some of the board copper trace failures
were confirmed during failure mode analysis. The mechanical connector
used on the board, connecting the board level circuitry to the test
gathering equipment is confirmed by its vendor data sheet to be
usuitable for mechanical shocks over 50g. The shocks administered in
steps 2.3 to 2.9 were much more severe than that. It is speculated that
Tin lead (SnPb) and Lead Free solder joints survived the stress levels
higher than 75G. So far, real board level failures have been observed
only for BGA devices.

ACI performed a limited Failure Mode Analysis (FMA) on BGA components.
Solder joint cross sections found several BGA solder balls had partially
traversed cracks, but no complete solder joint failure.

Intermittent test failures were a serious cause of concern. However, it
was felt that these intermittent failures were caused by two main
causes:

1.  Failure at the mechanical connector contact point and

2.  Real board level failures. The spring tension on the solder joint
    leads and making and breaking of contacts in each pulse. As a
    result, we felt that the failures were coming from the solder joints
    instead of extraneous sources. Therefore, the test was continued
    until the test level 2.7.

Based on very limited FMA, we have determined that the BGA devices did
not fail in the solder joints. All the noted failures were determined to
be test vehicle board copper trace failures, at the trace-BGA land neck
area. It is speculated that the shape of the BGA ball and the geometry
of the BGA land, contribute to a significant stress concentration at the
copper trace-BGA land neck area. During Z direction impact loading, the
resulting shock wave causes an overstress, consequentially shearing the
copper trace, as illustrated in Figure through Figure .

The solder joint cross-sections also indicate that a parallel failure
mode was also progressing. This parallel mode is solder joint fatigue.
As evidenced in Figure , Figure , and Figure , a crack within solder
joint was progressing simultaneously. We have not observed any BGA
solder joint with complete propagation of the crack, but after several
more shock cycles/pulses, the solder joint fatigue crack could become a
dominant failure mode. At this point the distinction between solder
types could have become more apparent.

![](media/image35.jpeg){width="2.9902777777777776in"
height="2.002083333333333in"}

[]{#__RefHeading___Toc130892170 .anchor}**Figure 29**: Board 29, SnPb
MANUFACTURED, BGA U44, PCB trace failure at BGA Ball 1R, illustrating a
complete failure

![](media/image40.jpeg){width="2.709722222222222in" height="2.0in"}

[]{#__RefHeading___Toc130892171 .anchor}**Figure 30**: Board 97,
SnAgCu/SnAgCu, BGA U44, PCB trace failure at BGA Ball 1B. As can be seen
this failure could cause intermittent electrical failures.

![](media/image33.jpeg){width="2.783333333333333in" height="2.0in"}

[]{#__RefHeading___Toc130892172 .anchor}**Figure 31**: Example of PCB
Trace failures in the corner of the BGA. Land Pads lifted cleanly,
separating at the conductor to land pad interfaces indicating a cracked
conductors. The area of separation was oxidized

![](media/image41.jpeg){width="2.283333333333333in" height="2.0in"}

[]{#__RefHeading___Toc130892173 .anchor}**Figure 32**: Example of Solder
Ball cracked on the component side. No failures of this type found but
small amount of cracking seen

A series of Lessons Learned were developed for future Mechanical Shock
tests at High G levels:

-   All data collection wires should be soldered directly into the test
    vehicle. Connectors should not be used unless rated above the shock
    test levels.

-   All wires and cables connected to the test vehicle should be
    shielded to prevent any potential effects from Electromagnetic
    Interference.

-   Hardware and data recording equipment should be grounded to earth
    ground, or a clean electrical system ground.

-   A thorough FMA of all failed assemblies is recommended to verify the
    solder performance at Hi-G levels of mechanical shock

# Conc**l**usions

Mechanical shock testing imposes a different stress mode and stress
level on the solder joints. Although these stresses are not common in
commercial electronics assemblies, most aviation electronics hardware
and some of the high performance military electronics parts need to
survive these Hi-G forces.

## Mechanical Shock Test-Procedure 1  {#mechanical-shock-test-procedure-1 .unnumbered}

The test results indicate that, at the normal crash test qualification
level (Test Level 1), there is minimal difference in the SnPb and the
two lead-free solder alloys used in this study; all three alloys meet
the test requirements. All alloys passed the Mechanical Shock
Test-Procedure 1, per the environmental stress screening testing
described in MIL-STD 810F; Method 516.5; Procedure 1. The tin lead
(SnPb) and tin silver copper (SnAgCu - SAC) soldered assemblies did not
have any failures. The tin silver copper bismuth (SnAgCuBi - SACB)
soldered assemblies had three (3) TQFP-208 components and one (1)
TSOP-50 component which failed. []{#__RefHeading___Toc130707059
.anchor}The TSOP-50 component failure can be attributed to the solder
extending past the heel fillet to the component's knee. The three (3)
TQFP-208 components passed continuity testing directly at the site on
the test vehicle board, bypassing (and so eliminating the effects of)
cables, connectors, and the long board copper traces. In each case, the
TQFP-20 was located at the U4 site of the test vehicle board. Other
JG-PP team members, performing other tests, have recorded questionable
indicated failures for that same U4 site. So it is suspected that the
solder joints for all three of the U4 designated TQFP-20 components
survived the test, since they were electrically continuous after the
test was over, but whatever the test vehicle "issue" was at the site of
U4 that caused indicated but probably not real failures in the temp.
cycle and vibration tests, also gave false failure indications in this
mechanical shock test.

**Mechanical Shock Test-Procedure 2**

At the higher shock levels, the failures were within interconnect chain,
but the failures were not necessarily at solder joints. Discontinuities
within the electronic package and the hardware instrumentation yielded
failures, which could not be distinguished from the real solder joints
failures. As a result the test data above 75 G shock is considered
confounded data. For these reasons we cannot draw definitive conclusion
about solder performance and the distinction between different solder
alloys is not very clear cut. As pointed out previously, thorough
failure analysis is required to pinpoint the failure modes.

Unlike other environmental tests, the mechanical shock testing imposes
stresses on all parts of the electrical continuity chain through the
board, connectors and cables that run back to the data logger, and not
just the solder joints. As a result the failures are not necessarily
located at the device-to-board solder joint connection. The shock pulse
stresses interconnections within the device package, within the silicon
device, board level wiring, board to mechanical connector connection,
the male-female connector connection and the external wiring harness
connection.

Based on very limited FMA conducted at the ACI, we have determined that
the BGA devices from Mechanical Shock Test-Procedure 2 did not fail in
the solder joints. All the noted failures were determined to be the
copper trace failures, at the trace-BGA land neck area. It is speculated
that the shape of the BGA ball and the geometry of the BGA land,
contribute to a significant stress concentration, at the copper
trace-BGA land neck area. During Z direction impact loading, the
resulting shock wave causes an overstress, consequentially shearing the
copper trace, as observed in Failure Mode Analysis at ACI.

The solder joint cross-sections also indicate that a parallel failure
mode was also progressing. This parallel mode is solder joint fatigue
during the 100 cycle duration of the tests. As evidenced in Figure ,
Figure , and Figure , a crack within the solder joint was progressing.
We have not observed any BGA solder joint with complete propagation of
the crack, but after several more shock cycles/pulses, the solder joint
fatigue crack could become a dominant failure mode. At this point (more
than 100 cycles) the distinction between solder types could have become
more apparent.

A series of Lessons Learned were developed for future Mechanical Shock
tests at high G levels:

-   All data collection wires should be soldered directly into the test
    vehicle. Connectors should not be used unless rated above the shock
    test levels.

-   All wires and cables connected to the test vehicle should be
    shielded to prevent any potential effects from Electromagnetic
    Interference.

-   Hardware and data recording equipment should be grounded to earth
    ground, or a clean electrical system ground.

-   A thorough FMA of all failed assemblies is recommended to verify the
    solder performance at Hi-G levels of mechanical shock.

Preliminary Failure Mode Analysis indicated that several copper traces
failed at the land-trace interface area. Failures within the electronic
package and the hardware instrumentation can also yield failures
indications, which need to be distinguished from the solder joint
failures to complete the relative solder performance evaluation. BGA
solder joint cross sections revealed that several BGA solder balls had
partially traversed cracks, but no complete failure.

.

# Acknowledgements

The authors would like to acknowledge the contributions of the following
individuals who participated in these tests:

L. Whiteman, American Competitiveness Institute

R. Macapagal, American Competitiveness Institute

R. Pappan, American Competitiveness Institute / Widener University

B. Partee, American Competitiveness Institute

S. Pepe, American Competitiveness Institute

A. Vigliotti, American Competitiveness Institute

J. Gilbert, American Competitiveness Institute

J. Bracco, BAE Systems

> L. Martin, BAE Systems

# Appendices

**Appendix A: Mechanical Shock Testing Procedure**

## **Appendix A:** Mechanical Shock Testing Procedure {#appendix-a-mechanical-shock-testing-procedure .unnumbered}

TEST VEHICLE:

There are 24 test boards available, documented by part number and serial
number. Test Boards are prepared with eutectic tin-lead solder and
lead-free solder alloys.

**TEST FACILITY:**

BAE Systems

Product Testing Lab

305 Richardson Road

Lansdale, PA 19446

TEST EQUIPMENT

+--------------+------------+---------------+-------+-----------------+
| *            | **Manu     | **Model**     | **S   | **Calibration   |
| *Equipment** | facturer** |               | erial | Due Date**      |
|              |            |               | \#**  |                 |
+--------------+------------+---------------+-------+-----------------+
| Vibr         | MB         | C-50          | 9944  | N/A             |
| ation/Shaker | E          |               |       |                 |
| Table \*\*   | lectronics |               |       |                 |
+--------------+------------+---------------+-------+-----------------+
| Fixture      | ACI        | \-            | \-    | N/A             |
+--------------+------------+---------------+-------+-----------------+
| Test Cables  |            |               |       |                 |
+--------------+------------+---------------+-------+-----------------+
| A            | Bruel &    | 4382          | 17657 | N/A             |
| ccelerometer | Kjaer      |               |       |                 |
| \*\*         |            |               |       |                 |
+--------------+------------+---------------+-------+-----------------+
| Vibration    | Spectral   | 2552B         | 20348 | N/A             |
| Control      | Dynamics   |               |       |                 |
| System \*\*  |            |               |       |                 |
+--------------+------------+---------------+-------+-----------------+
| Charge       | Unho       | D22           | 12538 | N/A             |
| Amplifier    | ltz-Dickie |               |       |                 |
| \*\*         |            |               |       |                 |
+--------------+------------+---------------+-------+-----------------+
| Event        | Anatech    | 128 / STD     | 8     | TBD             |
| Detector \*  | Event      |               | 80916 |                 |
|              | Detectors  | 256 / STD     |       |                 |
|              |            |               | TBD   |                 |
+--------------+------------+---------------+-------+-----------------+

\*\* Shock Test equipment will be as described above or equivalent

-   Requires personal computer to support the program

**TEST PROCESS**

The Test Vehicles (TV) shall consisted of JG-PP test boards, documented
by part number and serial number. Twenty-four (24) test vehicles
underwent mechanical shock testing, test set one of 12 boards were
tested according to table 1 and test set two of 12 boards were tested
according to table 2. During the test the electrical continuity of the
solder joints was continuously monitored.

The mechanical shock test was performed in two test sets as follows:

Test Set One: 12 Boards

4 Sn/Pb: Sn/Pb,

4 Sn/Ag/Cu: Sn/Ag/Cu

4 Sn/Ag/Cu/Bi: Sn/Ag/Cu/Bi

Apply shocks according to Table 1.

Test Set Two: 12 Boards

4 Sn/Pb: Sn/Pb

4 Sn/Ag/Cu: Sn/Ag/Cu,

4 Sn/Ag/Cu/Bi: Sn/Ag/Cu/Bi

Apply shocks according to Table 2.

NOTE: Boards within each test set were defined by the JG-PP Program

  ---------- ---------------- ----------- ----------- -------- -------- -------------- -------------------- ------------ ------------ ---------
  **Step**   **Test**         **Initial   **Slope**   **Peak   **Ts     **Cross-Over   **Z-axis\            **X-axis**   **Y-axis**   **Total
                              G**                     G**      (ms)**   Freq.**        (thru-thickness)**                             Shock**

  1.1        Functional test  4.5         6           20       15-23    45             3                    3            3            9
             for flight                                                                                                               
             equipment                                                                                                                

  1.2        Functional test  8.5         6           40       15-23    45             3                    3            3            9
             for ground                                                                                                               
             equipment                                                                                                                

  1.3        Crash Hazard     9           6           75       8-13     80             3                    3            3            9
             test for flight                                                                                                          
             equipment                                                                                                                

  1.4        Crash Hazard     9           6           75       8-13     80             100                  100          100          300
             test for flight                                                                                                          
             equipment                                                                                                                
  ---------- ---------------- ----------- ----------- -------- -------- -------------- -------------------- ------------ ------------ ---------

Table 1 Shock test for Test Set One, According to MIL-STD-810F, Method
516.5, Table 516.5-I

  ---------- -------------- ----------- ----------- -------- -------- -------------- --------------- ----- ------------ ---------
  **Step**   **Test**       **Initial   **Slope**   **Peak   **Ts     **Cross-Over   **Z-axis\       **X & **Reason**   **Total
                            G**                     G**      (ms)**   Freq.**        (thickness)**   Y**                Shock**

  2.1        Functional     4.5         6           20       15-23    45             100             NA    Fatigue in   100
             test for                                                                                      Z-axis only  
             flight                                                                                                     
             equipment                                                                                                  

  2.2        Functional     8.5         6           40       15-23    45             100             NA                 100
             test for                                                                                                   
             Ground                                                                                                     
             equipment                                                                                                  

  2.3        Crash Hazard   9           6           75       8-13     80             100             N/A                100
             test for                                                                                                   
             flight                                                                                                     
             equipment                                                                                                  

  2.4        Level 1        12          6           100      15-23    80\*           100             NA                 100

  2.5        Level 2        25          6           200      15-23    80\*           100             NA                 100

  2.6        Level 3        35          6           300      15-23    80\*           100             NA                 100

  2.7        Level 4        52          6           500      15-23    80\*           100             NA                 100

  2.8        Level 5        72          6           700      15-23    80\*           100             NA                 100

  2.9        Level 6        90          6           1000     15-23    80\*           100 or more     NA                 100
                                                                                     till majority                      
                                                                                     failure                            
  ---------- -------------- ----------- ----------- -------- -------- -------------- --------------- ----- ------------ ---------

Table 2 Shock test for Test 2

TEST CONDITIONS

**Each TV shall be connected to the event detector through cables;
either by hardwiring or by using connectors; the site test coordinator
shall determine the method.**

Test will be performed at ambient temperature

Four boards will be mounted on the fixture; So 4 boards will be tested
simultaneously. See Table 3 below for test board allocation.

The Event Detector equipment test parameters shall be as follows:

Continuously monitor the electrical continuity of the solder joints,
periodic monitoring is not

acceptable

Detect an electrical interruption lasting greater than 0.2 μsec.

Detect a continuity interruption \> 300 Ω

Record electrical events every 30 seconds minimum

+------+---------------+------+-------------+-----------+------------+
| Test | Test          | T    | M           | Man       | Ma         |
| Set  | Description   | otal | anufactured | ufactured | nufactured |
|      |               | B    | with Sn/Pb  | with SnPb | with SnPb  |
|      |               | oard | solder      | soder:    | solder:    |
|      |               |      |             |           |            |
|      |               |      | Reworked    | Reworked  | Reworked   |
|      |               |      | with Sn/Pb  | with      | with       |
|      |               |      | solder.     |           |            |
|      |               |      |             | Sn/Ag/Cu  | S          |
|      |               |      |             | solder    | n/Ag/Cu/Bi |
|      |               |      |             | wire for  |            |
|      |               |      |             | the PTH   | solder     |
|      |               |      |             | c         | wire for   |
|      |               |      |             | omponents | the PTH    |
|      |               |      |             | amd flux  | components |
|      |               |      |             | only for  | and flux   |
|      |               |      |             | the BGAs  | only for   |
|      |               |      |             |           | the BGAs   |
+------+---------------+------+-------------+-----------+------------+
| Set  | According to  | 12   | 4           | 4         | 4          |
| 1    | Table 1       |      |             |           |            |
+------+---------------+------+-------------+-----------+------------+
| Set  | According to  | 12   | 4           | 4         | 4          |
| 2    | Table 2       |      |             |           |            |
+------+---------------+------+-------------+-----------+------------+
|      |               |      |             |           |            |
+------+---------------+------+-------------+-----------+------------+

Table 3, Test Boards allocation

**TEST FIXTURE**

> ![](media/image42.jpeg){width="4.74375in"
> height="3.122916666666667in"}

[]{#__RefHeading___Toc130892174 .anchor}**Figure 33: Test Fixture**

PRETEST

The 64 net resistances of each test vehicle shall be measured and
recorded in the Test Log data sheet prior to the start of testing:

63 components on main TV (test vehicle)

1 plated through-hole loop on TV (test vehicle)

X-ray inspection of solder joints on each TV shall be documented prior
to test. Documentation of all anomalies found and the 'as assembled'
condition shall be part of the Test Log.

Visual/electrical examination may be used to supplement the X-ray
documentation of the anomalies/as-assembled solder joint conditions.
Visual criteria per J-STD-001, Class 3. X-ray criteria (shorts,
uniformity, and missing solder) per J-STD-001, Class 3.

Visual inspection of each TV shall be performed before and after the
test. Any damage or manufacturing condition that is out-of-specification
shall be documented in the Test Log.

DURING TEST

Continuously monitor the electrical continuity of the solder joints,
periodic monitoring is not acceptable. Detect an electrical interruption
lasting greater than 0.2 μsec.

Detect a continuity interruption \> 300 Ω up to 1000 Ω

Record electrical events every 30 seconds minimum

POST TEST

Test Log shall be completed during the performance of this test
procedure

The Test Log shall have the following sections:

Test Data Sheets

Thermal Profile Documentation

Inspection Documentation

Data Analysis

All Failure shall be documented on the test log and event detector
report. Inspection defects shall be noted on the test log.

TEST STEPS

  ------ ----------------------------------------------------------------
  Step   Description

  1      Measure Resistance of all 24 test boards & record data

  2      X-ray inspect solder joints of all 24 boards & record data

  3      Visually examine all boards for any damage & record data

  4      Program Shock controller

  5      Test the Shock profile without fixture mounted on table to
         conform the profile
  ------ ----------------------------------------------------------------

+-----+----------------------------------------------------------------+
| **T |                                                                |
| est |                                                                |
| Set |                                                                |
| O   |                                                                |
| ne: |                                                                |
| T   |                                                                |
| est |                                                                |
| acc |                                                                |
| ord |                                                                |
| ing |                                                                |
| to  |                                                                |
| Ta  |                                                                |
| ble |                                                                |
| 1** |                                                                |
|     |                                                                |
| 12  |                                                                |
| B   |                                                                |
| oar |                                                                |
| ds, |                                                                |
| 4   |                                                                |
| Sn/ |                                                                |
| Pb: |                                                                |
| Sn/ |                                                                |
| Pb, |                                                                |
| 4   |                                                                |
| Sn/ |                                                                |
| Ag/ |                                                                |
| Cu: |                                                                |
| Sn/ |                                                                |
| Ag/ |                                                                |
| Cu, |                                                                |
| 4   |                                                                |
| Sn/ |                                                                |
| Ag/ |                                                                |
| Cu/ |                                                                |
| Bi: |                                                                |
| Sn  |                                                                |
| /Ag |                                                                |
| /Cu |                                                                |
| /Bi |                                                                |
+-----+----------------------------------------------------------------+
| 6   | Mount (4) Sn/Pb:Sn/Pb boards on the fixture                    |
+-----+----------------------------------------------------------------+
| 7   | Set the Shaker table for shock on Z direction                  |
+-----+----------------------------------------------------------------+
| 8   | Apply 3 shock on Positive Z Direction according to step 1.1    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 9   | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 10  | Apply 3 shock on Positive X Direction according to step 1.1    |
+-----+----------------------------------------------------------------+
| 11  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 12  | Apply 3 shock on Positive Y Direction according to step 1.1    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 13  | Set the Shaker setting for shock on Z direction                |
+-----+----------------------------------------------------------------+
| 14  | Apply 3 shock on Positive Z Direction according to step 1.2    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 15  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 16  | Apply 3 shock on Positive X Direction according to step 1.2    |
+-----+----------------------------------------------------------------+
| 17  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 18  | Apply 3 shock on Positive Y Direction according to step 1.2    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 19  | Set the Shaker table for shock on Z direction                  |
+-----+----------------------------------------------------------------+
| 20  | Apply 3 shock on Positive Z Direction according to step 1.3    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 21  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 22  | Apply 3 shock on Positive X Direction according to step 1.3    |
+-----+----------------------------------------------------------------+
| 23  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 24  | Apply 3 shock on Positive Y Direction according to step 1.3    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 25  | Set the Shaker table for shock on Z direction                  |
+-----+----------------------------------------------------------------+
| 26  | Apply 3 shock on Positive Z Direction according to step 1.4    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 27  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 28  | Apply 3 shock on Positive X Direction according to step 1.4    |
+-----+----------------------------------------------------------------+
| 29  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 30  | Apply 3 shock on Positive Y Direction according to step 1.4    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 31  | Disconnect data logger & event detector to all four board &    |
|     | stop collecting data                                           |
+-----+----------------------------------------------------------------+
| 32  | Remove boards from fixture & Mount next (4) Sn/Ag/Cu:Sn/Ag/Cu  |
|     | Boards on Fixture                                              |
+-----+----------------------------------------------------------------+
| 33  | Set Shaker table for Shock on Z direction                      |
+-----+----------------------------------------------------------------+
| 34  | Apply 3 shock on Positive Z Direction according to step 1.1    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 35  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 36  | Apply 3 shock on Positive X Direction according to step 1.1    |
+-----+----------------------------------------------------------------+
| 37  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 38  | Apply 3 shock on Positive Y Direction according to step 1.1    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 39  | Set the Shaker setting for shock on Z direction                |
+-----+----------------------------------------------------------------+
| 40  | Apply 3 shock on Positive Z Direction according to step 1.2    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 41  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 42  | Apply 3 shock on Positive X Direction according to step 1.2    |
+-----+----------------------------------------------------------------+
| 43  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 44  | Apply 3 shock on Positive Y Direction according to step 1.2    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 45  | Set the Shaker table for shock on Z direction                  |
+-----+----------------------------------------------------------------+
| 46  | Apply 3 shock on Positive Z Direction according to step 1.3    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 47  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 48  | Apply 3 shock on Positive X Direction according to step 1.3    |
+-----+----------------------------------------------------------------+
| 49  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 50  | Apply 3 shock on Positive Y Direction according to step 1.3    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 51  | Set the Shaker table for shock on Z direction                  |
+-----+----------------------------------------------------------------+
| 52  | Apply 3 shock on Positive Z Direction according to step 1.4    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 53  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 54  | Apply 3 shock on Positive X Direction according to step 1.4    |
+-----+----------------------------------------------------------------+
| 55  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 56  | Apply 3 shock on Positive Y Direction according to step 1.4    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 57  | Disconnect data logger & event detector to all four board &    |
|     | stop collecting data                                           |
+-----+----------------------------------------------------------------+
| 58  | Remove boards from fixture & Mount next (4)                    |
|     | Sn/Ag/Cu/Bi:Sn/Ag/Cu/Bi Boards on Fixture                      |
+-----+----------------------------------------------------------------+
| 59  | Set the shaker table for shock on Z direction                  |
+-----+----------------------------------------------------------------+
| 60  | Apply 3 shock on Positive Z Direction according to step 1.1    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 61  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 62  | Apply 3 shock on Positive X Direction according to step 1.1    |
+-----+----------------------------------------------------------------+
| 63  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 64  | Apply 3 shock on Positive Y Direction according to step 1.1    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 65  | Set the Shaker setting for shock on Z direction                |
+-----+----------------------------------------------------------------+
| 66  | Apply 3 shock on Positive Z Direction according to step 1.2    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 67  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 68  | Apply 3 shock on Positive X Direction according to step 1.2    |
+-----+----------------------------------------------------------------+
| 69  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 70  | Apply 3 shock on Positive Y Direction according to step 1.2    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 71  | Set the Shaker table for shock on Z direction                  |
+-----+----------------------------------------------------------------+
| 72  | Apply 3 shock on Positive Z Direction according to step 1.3    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 73  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 74  | Apply 3 shock on Positive X Direction according to step 1.3    |
+-----+----------------------------------------------------------------+
| 75  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 76  | Apply 3 shock on Positive Y Direction according to step 1.3    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 77  | Set the Shaker table for shock on Z direction                  |
+-----+----------------------------------------------------------------+
| 78  | Apply 3 shock on Positive Z Direction according to step 1.4    |
|     | (table 1)                                                      |
+-----+----------------------------------------------------------------+
| 79  | Rotate fixture on table for X direction Shock                  |
+-----+----------------------------------------------------------------+
| 80  | Apply 3 shock on Positive X Direction according to step 1.4    |
+-----+----------------------------------------------------------------+
| 81  | Change Shaker settings for Shock on Y direction                |
+-----+----------------------------------------------------------------+
| 82  | Apply 3 shock on Positive Y Direction according to step 1.4    |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 83  | Disconnect data logger & event detector to all four board &    |
|     | stop collecting data                                           |
+-----+----------------------------------------------------------------+
| 84  | Remove boards from fixture                                     |
+-----+----------------------------------------------------------------+
| 85  | Visually examine boards for any damage & record data           |
+-----+----------------------------------------------------------------+

+-----+----------------------------------------------------------------+
| **T |                                                                |
| est |                                                                |
| Set |                                                                |
| T   |                                                                |
| wo: |                                                                |
| T   |                                                                |
| est |                                                                |
| acc |                                                                |
| ord |                                                                |
| ing |                                                                |
| to  |                                                                |
| Ta  |                                                                |
| ble |                                                                |
| 2** |                                                                |
|     |                                                                |
| 12  |                                                                |
| B   |                                                                |
| oar |                                                                |
| ds: |                                                                |
| 4   |                                                                |
| Sn/ |                                                                |
| Pb: |                                                                |
| Sn/ |                                                                |
| Pb, |                                                                |
| 4   |                                                                |
| Sn/ |                                                                |
| Ag/ |                                                                |
| Cu: |                                                                |
| Sn/ |                                                                |
| Ag/ |                                                                |
| Cu, |                                                                |
| 4   |                                                                |
| Sn/ |                                                                |
| Ag/ |                                                                |
| Cu/ |                                                                |
| Bi: |                                                                |
| Sn/ |                                                                |
| Ag/ |                                                                |
| Cu/ |                                                                |
| Bi) |                                                                |
+-----+----------------------------------------------------------------+
| 86  | Mount (4) Sn/Pb:Sn/Pb Boards on the fixture                    |
+-----+----------------------------------------------------------------+
| 87  | Connect data logger & event detector to all four boards &      |
|     | Start collecting data                                          |
+-----+----------------------------------------------------------------+
| 88  | Set Shaker for Shock on Z Direction                            |
+-----+----------------------------------------------------------------+
| 89  | Mount Fixture on the Shaker Table                              |
+-----+----------------------------------------------------------------+
| 90  | Apply 100 Shocks in Z direction according to step 2.1 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 91  | Apply 100 Shocks in Z direction according to step 2.2 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 92  | Apply 100 Shocks in Z direction according to step 2.3 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 93  | Apply 100 Shocks in Z direction according to step 2.4 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 94  | Apply 100 Shocks in Z direction according to step 2.5 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 95  | Apply 100 Shocks in Z direction according to step 2.6 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 96  | Apply 100 Shocks in Z direction according to step 2.7 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 97  | Apply 100 Shocks in Z direction according to step 2.8 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 98  | Apply 100 or more Shocks in Z direction till majority          |
|     | component fail, according to step 2.9 (Table 2)                |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 99  | Disconnect data logger & event detector and stop collecting    |
|     | data                                                           |
+-----+----------------------------------------------------------------+
| 100 | Remove boards from the fixture & visually examine the boards   |
|     | -- record results                                              |
+-----+----------------------------------------------------------------+
| 101 | Mount next 4 Sn/Ag/Cu:Sn/Ag/Cu Boards on Fixture               |
+-----+----------------------------------------------------------------+
| 102 | Connect data logger & event detector to all four boards &      |
|     | Start collecting data                                          |
+-----+----------------------------------------------------------------+
| 103 | Set Shaker for Shock on Z Direction                            |
+-----+----------------------------------------------------------------+
| 104 | Mount Fixture on the Shaker Table                              |
+-----+----------------------------------------------------------------+
| 105 | Apply 100 Shocks in Z direction according to step 2.1 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 106 | Apply 100 Shocks in Z direction according to step 2.2 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 107 | Apply 100 Shocks in Z direction according to step 2.3 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 108 | Apply 100 Shocks in Z direction according to step 2.4 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 109 | Apply 100 Shocks in Z direction according to step 2.5 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 110 | Apply 100 Shocks in Z direction according to step 2.6 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 111 | Apply 100 Shocks in Z direction according to step 2.7 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 112 | Apply 100 Shocks in Z direction according to step 2.8 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 113 | Apply 100 or more Shocks in Z direction till majority          |
|     | component fail, according to step 2.9 (Table 2)                |
+-----+----------------------------------------------------------------+
|     |                                                                |
+-----+----------------------------------------------------------------+
| 114 | Disconnect data logger & event detector and stop collecting    |
|     | data                                                           |
+-----+----------------------------------------------------------------+
| 115 | Remove boards from the fixture & visually examine the boards   |
|     | -- record results                                              |
+-----+----------------------------------------------------------------+
| 116 | Mount next 4 Sn/Ag/Cu/Bi:Sn/Ag/Cu/Bi Boards on Fixture         |
+-----+----------------------------------------------------------------+
| 117 | Connect data logger & event detector to all four boards &      |
|     | Start collecting data                                          |
+-----+----------------------------------------------------------------+
| 118 | Set Shaker for Shock on Z Direction                            |
+-----+----------------------------------------------------------------+
| 119 | Mount Fixture on the Shaker Table                              |
+-----+----------------------------------------------------------------+
| 120 | Apply 100 Shocks in Z direction according to step 2.1 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 121 | Apply 100 Shocks in Z direction according to step 2.2 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 122 | Apply 100 Shocks in Z direction according to step 2.3 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 123 | Apply 100 Shocks in Z direction according to step 2.4 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 124 | Apply 100 Shocks in Z direction according to step 2.5 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 125 | Apply 100 Shocks in Z direction according to step 2.6 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 126 | Apply 100 Shocks in Z direction according to step 2.7 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 127 | Apply 100 Shocks in Z direction according to step 2.8 (Table   |
|     | 2)                                                             |
+-----+----------------------------------------------------------------+
| 128 | Apply 100 or more Shocks in Z direction till majority          |
|     | component fail, according to step 2.9 (Table 2)                |
+-----+----------------------------------------------------------------+
| 129 | Disconnect data logger & event detector and stop collecting    |
|     | data                                                           |
+-----+----------------------------------------------------------------+
| 130 | Remove boards from the fixture & visually examine the boards   |
|     | -- record results                                              |
+-----+----------------------------------------------------------------+
| 131 | End test                                                       |
+-----+----------------------------------------------------------------+

Each TV shall be connected to the event detector through cables, either
by hardwiring or by using connectors; the site test coordinator shall
determine the method.

The Event Detector equipment test parameters shall be as follows:

Continuously monitor the electrical continuity of the solder joints,
periodic monitoring is not acceptable

Detect an electrical interruption lasting greater than 0.2 μsec.

Detect a continuity interruption [\>]{.underline} 300 Ω up to 1000 Ω

Record electrical events every 30 seconds minimum

##   {#section-10 .unnumbered}