Highly reliable die attachment on polished GaAs surfaces using gold-tin eutectic alloy

GaAs test dice with polished surfaces were successfully bonded on alumina substrates using Au-Sn alloy. The bonding process was carried out in H/sub 2/ or N/sub 2/ atmosphere with applied static pressure, but without the use of scrubbing. The quality of the bonds was examined by a scanning acoustic microscope (SAM) having a spatial resolution of 25 mu m. After 100 cycles of thermal shock between -196 degrees C to +160 degrees C, perfectly bonded devices remained perfect, as confirmed by the SAM images. No void was induced, and the dice did not crack. The results of a shear test indicate that the strength of the bondings is greater than that of the GaAs dice.<
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