A micromachined packaging with incorporated RF-choke for integration of active chips at submillimeter-wave frequencies

This paper presents the design, fabrication and evaluation of a novel packaging method for integration of active MMIC at millimeter-wave (MMW) and sub-MMW frequencies. This packaging approach is intended for integration with a micromachined sub-MMW radar system operating at 240 GHz. The concept is based on a peg and socket structure composed of RF transitions and biasing circuitry where the RF and DC pads on the MMIC chip mate with the on-wafer RF transitions and biasing pads, respectively, for a seamless packaging method. To prevent instability of the packaged active device, an ultrawideband RF-choke is devised to provide better than 15 dB of RF isolation between the chip and the biasing circuitry from 30 GHz to 330 GHz. A prototype of the RF-choke along with the rest of the packaging block is fabricated using multi-layer silicon mi-cromachining technology at Y-band (i.e. 220-325 GHz) and the performance is measured where close agreement of the measured and simulated results is shown. Additionally, the proposed integration method is used for packaging of an amplifier at 210 GHz where excellent RF and biasing results are achieved.