Solid-Liquid Interdiffusion Bonding of Copper Using Ag-Sn Layered Films

Abstract

Newly developed bonded materials and fabrication processes are expected to firmly bond copper leads to SiC chips for application in next generation power modules. Solid-liquid interdiffusion bonding of copper was performed using Ag-Sn layered films. Microstructural development and mechanical properties of bond layers were investigated. The bond layer grew at the thin film interfaces because of the solidliquid interdiffusion. Cu 6 Sn 5 and Ag 4 Sn or Ag 3 Sn phases were formed at the initial bonding stage, and subsequently, Cu 3 Sn formed between the Cu 6 Sn 5 and Cu as both bond time and temperature increased. Finally, the bond layer was primarily composed of Ag 4 Sn and Cu 3 Sn. The hardness and Young's modulus of Ag 4 Sn were much lower than those of Cu 3 Sn. The growth of the Cu 3 Sn layer that formed between Ag 4 Sn and Cu could be limited by optimizing the design of the faying surface.

Solid-Liquid Interdiffusion (SLID) Bonding of p-Type Skutterudite Thermoelectric Material Using Al-Ni Interlayers

“…The SLID bonding technique is based on binary interlayer systems comprising a high-melting-point material, T M HIGH , and a low-melting-point material, T M LOW , which is heated to its molten state, resulting in the formation of intermetallic compounds (IMCs) through a diffusion-reaction mechanism. SLID bonding has been commonly explored using Sn and In as T M LOW filler systems [21,22,23,24,25] with several advantages over standard solder interconnections such as outstanding thermal stability due to increased re-melting temperature and power handling capability with current densities exceeding the capability of solders [26]. However, SLID technology faces many limitations before industrial implementation due to having a relatively slow and time-consuming diffusion controlled reaction along with inherent Kirkendall voiding and shrink holes created within the bonding material [18].…”

Effect of Zinc Addition on Void Formation in Solid-Liquid Interdiffusion Bonding of Copper

“…In solid-liquid interdiffusion bonding, metals with low melting points such as Sn and In are sandwiched between copper bases and heated above the melting point of the inserted materials to realize die bonding by solid-liquid reaction diffusion. [1][2][3][4][5][6] The liquid phase then reacts with the base copper to form a bond layer of intermetallic compounds (IMCs) that exhibits a higher melting point than the melting point of the inserted material.…”