RELIABILITY TEST PROGRAM OF ULTRASONIC FACE DOWN BONDING TECHNIQUE
Technical Report,10 Nov 1965,31 Jan 1967
SPERRY RAND CORP PHILADELPHIA PA PHILADELPHIA
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A study was made to determine the overall reliability of its face-down-bonding process and to determine whether the bonding process damages the chip. The ultrasonic direct-bonding process was used to fabricate approximately 900 test samples for this study. Samples were subjected to the following tests shear, mechanical shock, thermal shock, vibration, centrifuge, high-temperature storage, elevated-temperature back bias, step stress and comparison, and temperature and humidity. Defective units were examined for causes of failure. The test results indicate that the stresses applied during bonding do not affect circuit operation. The bond failure rate was high, but the distribution of failures suggests that this was due to inadequate substrate process control rather than inherent problems with face-down bonding. The substrate interconnect wires corroded in high-temperature and high-humidity ambients. Several potential solutions to this problem are suggested.