After the PCBA resistor is used for a period of time, the failure failure occurs poorly, and according to this situation, the failure resistor is analyzed to clarify the cause of failure.
The main connection point for data communication:
Resistance Test Results:
Test results: The third circuit of RP2 and RP5 was found to have abnormally large resistance values (open circuit).
RP2 Failure Exclusion (state on board):
RP5 Failure Exclusion (state on board):
Test results: No significant abnormalities.
RP2 Failure Exclusion (Removed State):
RP5 Failure Exclusion (Removed State):
Test results: After RP2 and RP5 were removed, the resistance value (3 channels) was confirmed, and all of them were in an open circuit state, and there was no abnormality in X-ray detection.
RP2 Exclusion SEM Analysis:
Test results: RP2 and RP5 resistors have obvious surface protective films on the terminal electrode side, and all of them are in a loose pore state.
RP2 Exclusion EDS Analysis:
Test Results: No anomalous elements found.
Microscopic observation of RP2 after exclusion after opening:
SEM analysis after RP2 exclusion barrier opening:
Test results: There is an obvious open circuit at the 3 channel position, and the AG connection is missing, resulting in an open circuit. At the same time, the 4th and 5th channels all have the phenomenon of AG defects, and only a few are connected.
EDS analysis after RP2 exclusion opening (surface scanning):
EDS analysis after RP2 exclusion opening (spot scanning):
Test results: EDS analysis showed that the RP2 was defective and no abnormal elements were found.
RP5 cross-sectional analysis
Test results: From a macroscopic analysis, there are cracking anomalies on both sides of the resistorLocal analysis showed that the AG electrode of the R5 side end electrode was defective.
1. Resistance RP2, RP5 third open circuit (RP2: 11.)86mω，rp5:20.24 m, standard value 22 );
2. From the analysis of RP2 opening, it can be seen that there is a large potential failure risk of exclusion.
3. RP5 cross-section analysis (3-way position), there are cracking anomalies (45° crack + Y-type crack) at the side end of RP5, and AG electrode defects at the side end of RP5.
The surface porosity and porosity are abnormal.
Connect Open Circuit (AG).
There are obvious stress cracks in the end electrode.
In summary, the possible causes of poor resistor function failure are as follows
1. The protective film of the resistor itself is defective, and the AG dielectric layer is susceptible to external stress, including mechanical and environmental influences, and cracking;
2.The resistor is subjected to continuous stress, which causes damage to the connection of the electrode part.
1.DPA analysis of resistors to ensure their reliability;
2.Troubleshooting analysis for possible stresses**.
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