In this study,the thermal compression bonding using 70μm-pitch Cu/Ni/SnAg1.8 pillar with two heating method was successfully demonstrated.Results showed that as both the top bonding head and the bottom plate were heating to 250℃,the solder joints were in good quality and no bridging joints or cold joints were observed,the inter-metallic compounds(Cu,Ni)6Sn5 grew up completely and continuously and the thickness was about 1.38 µ m,the shear strength of flip chip was qualified.When the bottom plate was kept at 150℃,as the heating temperature of top bonding head increased,the growth of intermetallic compounds(Cu,Ni)6Sn5 gradually became complete and continuous,the thickness gradually increased,the resistance firstly increased and then decreased,and the shear strength increased gradually.When the temperature of bottom plate was kept at 150℃ and the heating temperature of the bonding head was 350℃,the resistance,intermetallic compound thickness,and shear strength of the circuit were equivalent to those of the circuit where both the bonding head and the bottom plate were heated to 250 ℃.This process provided data support for the Chip to Wafer(C2W)thermal compression bonding process.
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