The conventional method of attaching MEM inertial sensors in ceramic chip carriers is to braze them to the floor of the package using gold-tin braze of eutectic composition. The attachment leaves the assembly in a state of high residual stress, which raises concerns about its mechanical stability, particularly for high performance sensor applications. Thermal compression bonding die to gold bumps within chip carrier packages avoids the shortcomings of braze attach. However, the concentrated loads applied to the sensor die through the gold bumps can result in bond failure when the assembly is subjected to mechanical or thermal induced loads. Care must be taken in designing gold bump bonded assemblies for the anticipated operational environment. This is particularly true when the bumps are used to make electrical connections. This paper examines the mechanical performance of gold bump bonded MEM sensor assemblies that are subjected to thermal and inertial loads. Mechanical pull tests, liquid to liquid thermal shocks and high-G rail gun tests are used to obtain performance data.
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