Interconnects for a multi-layer three-dimensional silicon architecture

As low cost and low volume gain increasing importance in today's technology market, the development of lateral and vertical interconnects for K- throu gh W-band applications using silicon micromachining is a worthwhile endeavo r. Thus, lateral components appropriate for multi-layer applications, such as Wilkinson dividers, reactive tees and right angle bends, have been devel oped at 94 GHz. Wafer-to-wafer interconnects with only 0.1 dB insertion los s have also been developed in addition to vertical through-wafer interconne cts with 0.5 dB insertion loss at 94 GHz. These components are integrated i nto a multi-layer silicon, micromachined power cube, 6 mm in length, 6 mm i n width, 1 mm in height, that represents the first W-band (94 GHz) transmit module to date. The multi-layer silicon environment, with appropriate desi gn and packaging, yields a solution to the low power problems of convention al monolithic microwave integrated circuits (MMIC) by providing more power per unit area. This article presents details of the passive components and interconnects involved for a 94 GHz design, although they may also be appli ed to lower frequencies.