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论文类型：会议论文

发表时间：2015-05-26

收录刊物：EI、CPCI-S、Scopus

卷号：2015-July

页面范围：1616-1623

关键字：fine-pitch interconnect; solid-state-diffusion bonding; microstructure; Kirkendall voids

摘要：3D interconnection is one of the key technologies for future's 3D integration. Cu/Sn/Cu Solid-State-Diffusion (SSD) bonding has been proposed and investigated for fine-pitch interconnection in this paper. Wafer-level bumps, with 20 mu m-pitch and daisy-chain and Kelvin structures, were pretreated for surface activation and bonded face to face with a wafer bonder. After bonding at 200 degrees C for 1hour, the as-bonded interfacial microstructure is Cu/Cu3Sn/Cu6Sn5/Cu3Sn/Cu, without pure Sn remained. When the bonded wafers were annealed at 200 degrees C for 30min under N-2 atmosphere, the Cu6Sn5 was almost exhausted. And the bonding strength increased from 48MPa to 62MPa. The electrical resistance of the daisy chain including 100 bumps is 11.8 Omega, which consisting of redistribution layer and bonding bumps. Additionally, the resistance of the Kelvin structure is 15m Omega. The resistance values are approximate to the theory estimation. Bonding pairs after high temperature storage (HTS) at 150 degrees C for 500hrs were checked for reliability study. Kirkendall voids with various dimensions are discussed for both as-bonded and annealing interfaces. It is concluded that Cu/Sn/Cu SSD bonding would be one of the candidates for finepitch interconnect.