Electrical Demonstration of an RF Embedded Multichip Module Enabled by Fused-Silica Stitch-Chip Technology

An RF multichip module (MCM) using commercial off-the-shelf (COTS) chips is demonstrated with a proposed fused-silica stitch-chip technology for the first time. In this article, simulations indicate that the stitch chip possesses much lower loss than wire/ribbon bonds. Multiple design cases of die-to-die (D2D) interconnects using stitch chips are explored. A bare low noise amplifier (LNA) die and a bare switch die for K/Ka-band are embedded in a package substrate, where the fabricated stitch chips are then assembled. RF characterization is performed for the assembled module. The packaged LNA establishes <1-dB package-induced linear gain degradation and >12-dB return loss, while the interconnected LNA and switch module are functional and establish a 15-dB linear gain. The proposed fused-silica stitch-chip technology is a promising integration solution for future RF modules.