Cu-Sn transient liquid phase wafer bonding for MEMS applications

The impact of process parameters on final bonding layer quality was investigated for Transient Liquid Phase (TLP) wafer-level bonding based on the Cu-Sn system. Subjects of this investigation were bonding temperature profile, bonding time and contact pressure as well as the choice of metal deposition method and the ratio of deposited metal layer thicknesses. Typical failure modes in Inter-Metallic Compound (IMC) growth for the mentioned process and design parameters were identified and subjected to qualitative and quantitative analysis. The possibilities to avoid abovementioned failures are indicated based on experimental results. © 2013 SPIE.