点击次数：

论文类型：会议论文

发表时间：2016-05-31

收录刊物：EI、CPCI-S、Scopus

卷号：2016-August

页面范围：1765-1771

关键字：3D interconnection; solid-state-diffusion (SSD) bonding; plasma pretreatment; surface activation

摘要：In this work, Ar mixed 5% H-2 plasma was applied to improve the surface properties of electroplated Cu and electroplated Sn for Cu/Sn/Cu solid-state-diffusion (SSD) bonding in 3D interconnection. The surfaces of electroplated Cu and electroplated Sn were easily covered with a thin oxide layer which would reduce the surface activity and degenerate the bonding performance. With an optimal pretreatment time of 120s, the contact angle of electroplated Cu decreased from 29 degrees to below 10 degrees. However, the optimal pretreatment time was only 60s for contact angle of electroplated Sn with a reduction from 36 degrees to below 5 degrees. The average roughness of electroplated Cu and electroplated Sn was also reduced to 6.8nm and 78.0nm respectively. And the electroplated Cu and electroplated Sn could keep a more stable surface activity after storage in clean room for 30min and 60min. Subsequently, a sandwich-structure Cu/Sn/Cu interconnection with a pitch of 20 degrees m was realized at 200 degrees C in wafer level using solid-statediffusion (SSD) bonding. The as-bonded interface consisted of Cu/Cu3Sn/Cu6Sn5/Cu3Sn/Cu, without pure Sn remained and Sn overflow. The interface transformed to Cu/Cu3Sn/Cu as exhausting Cu6Sn5 after an annealing process. Higher shear strength and lower daisy-chain resistant were also obtained. And the bonding properties also degenerated less after high temperature storage (HTS) test. It is concluded that the optimal Ar(5% H-2) plasma pretreatment could effectively activate the surface of bump and improve Cu/Sn/Cu SSD bonding for future's 3D interconnection.