Cu-SnAg Interconnects Evaluation for the Assembly at 10µm and 5µm Pitch

Several types of interconnects for the finer pitch assembly are currently being investigated across the globe. Here in this paper, a new type of interconnect Ni3Sn4 Interconnect is proposed and evaluated for assembly at 10 pitch and below. The proposed interconnect is compared to traditional solder interconnect. The comparison is done on the basis of shape of the joints in interconnects, the electric yield and mechanical properties. Later, Ni3Sn4 IMC interconnect is also compared to known Cu3Sn IMC Interconnect.

I. Introduction

According to Moore's law, the number of transistors per unit area on integrated circuits double itself every year which entails the proportional increase of interconnects density on these integrated circuits. As a result, the 2D integration (using wire bonding for interconnect) is replaced by 3D integration (using microbumps and TSVs). Following this trend, in coming years the interconnect density for several applications such as micro display, imaging devices will approach the pitch of and below. Some research centers across the globe are working to achieve the assembly at finer pitch. Many approaches for making these interconnects such as Cu-solder bonding, microtubes, Cu-Cu bonding etc. are proposed, however the research is still in its early stages.