In this presentation, an innovative high throughput TCB process, Liquid Phase Contact Thermal Compression Bonding (LPC TCB) process under Inert environment, for fine-pitch copper pillar with solder cap flip chip packages, will be introduced. It offers not only high throughput but also reliable interconnection. A series of LPC TCB experimental data using both Chip-on-Substrate (CoS) and Chip-on-Chip (CoC) packages with both Cu/OSP and Ni/Au substrate finishes will be reviewed. It is demonstrated that the solder thickness (standoff height) after assembly could be precisely controlled. With a bond head cooling step, a precise solder height can be obtained based on a pre-determined bonding level, while without a bond head cooling step, the solder height remains at a constant value regardless the bonding level. The restoring force from the surface tension is calculated to explain this phenomenon. The LPC TCB bonding profile clearly indicates a high throughput. Without a cooling step, the unit per hour (UPH) could be as high as close to 2K.
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