PowerTherm Attach Process for Power Delivery and Heat Extraction in the Silicon-Interconnect Fabric Using Thermocompression Bonding

Abstract

High-density placement of dies on the Silicon Interconnect Fabric (Si-IF) demands high power delivery (1 W/mm2) which in turn generates intense heat (~0.5-0.7 W/mm2). To meet this power requirement and manage its thermal dissipation, we have introduced a novel architecture called PowerTherm which involves the attachment of electrically isolated copper terminal blocks to the back side of the Si-IF. The terminal blocks perform a dual function: they deliver high current at mission voltage and cool the Si-IF either passively or actively. This paper deals with PowerTherm bonding process and its characterization. The terminal blocks were attached to electrodeposited Cu on Si using thermocompression bonding in atmospheric conditions, however with confined air flow. Shear strength of ~ 17 MPa was achieved when the bonding was performed at the optimized conditions.