1. Assessment of Fluxless Solid Liquid Interdiffusion Bonding by Compressive Force of Au-PbSn and Au-SAC for Flip Chip Packaging
- Author
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A.C. Tan, Teck Kheng Lee, Chee C. Wong, and Sam Zhang
- Subjects
Wire bonding ,Interconnection ,Materials science ,Metallurgy ,Electronic packaging ,Substrate (electronics) ,Die (integrated circuit) ,Reflow soldering ,Compressive strength ,Soldering ,Electrical and Electronic Engineering ,Composite material ,Flip chip ,Diffusion bonding - Abstract
Flip chip packaging faces two primary bonding-process obstacles: flux use and geometry mismatch between die and substrate pad pitch. These obstacles motivated the development of a fluxless bonding method called solid-liquid interdiffusion bonding by compressive force (SLICF). SLICF utilizes a mechanical force to form the bond through solid-liquid interdiffusion with a joint-in-via (JIV) architecture for flip chip packaging. SLICF bonding (also known as thermo-mechanical (TM) bonding) forms an instantaneous bond and eliminates the need for reflow infrastructure. Both Au-PbSn and Au-SAC interconnect systems were studied for the SLICF bonding on the JIV architecture at a 130- mum pitch. The morphologies of Au-PbSn and Au-SAC in solid-liquid interdiffusion were studied with their kinetics measured by the Au consumption rate. The SLIFC bonds for Au-PbSn and Au-SAC were compared and assessed by mechanical shear tests and thermomechanical stresses. Au with PbSn was found to perform marginally better due to its joint geometry and slower kinetics.
- Published
- 2009