Strain induced by bonding a GaAs chip on a copper heatsink plate has been measured with a reflection type of infrared polariscope. It is found that the bonding-induced strain reaches the order of 10/sup -4/, which corresponds to about 1/10 of that estimated from the thermal expansion difference for the unit length between GaAs and copper when it is cooled down from the die-bonding temperature to the room temperature.
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