Thermal and Electrical Characterization of TSV Interposer Embedded with Microchannel for 2.5D Integration of GaN RF Devices

In this paper, a TSV interposer embedded with microchannel is proposed for 2.5D integration of GaN RF power device. S-shaped microchannel with symmetrical radial diversion structure in inlet/outlet region is designed to make a balance among process, cooling property and flow resistance. In order to avoid issues regarding to fabrication of TSV interconnections on thick bonded Si wafer embedded with microchannels, TSV is designed as having three different diameters along its axis which are 100mm, 180mm and 220mm in sequence from the bottom end to the top end and total height of 500mm. A process is developed with Si-Si wafer bonding process for the proposed TSV interposer embedded with S-shaped microchannel that is 50mm/100mm in its width/pitch, 300mm in the depth. Sample of TSV interposer embedded with microchannel is fabricated and tested electrically, it has a tested resistance about 6mW for TSV interconnection. In order to validate the proposed TSV interposer, A GaN RF power amplifier chip which has an equivalent thermal flux about 400W/cm2 is utilized as test vehicle and 2.5D integrated GaN RF power amplifier based TSV interposer with embedded cooling microfluidics is designed, assembled and tested. The experimental result show that 2.5D integrated GaN Power amplifier can work correctly.