Demonstration of a Low Loss W-band Interconnect and Circuit Isolation Structure for Wafer Scale Assembly

In this paper, we demonstrate wafer scale assembly (WSA) technology at W-band frequencies. This technology enables compact and high performance millimeter-wave modules to be manufactured using the high volume, batch fabrication processes that are currently used to produce MMIC´s. Key features of WSA are vertical, low loss interconnects that are fabricated with a high level of uniformity, and compact MMIC channelization through the use of isolation fences. In this paper, we demonstrate vertical WSA interconnects with less than 0.2 dB of insertion loss at W-band with high levels of uniformity. We also demonstrate a single isolation fence that provides 30 dB of isolation. This technology has the potential to vertically integrated several MMIC layers to form compact, multilayer millimeter-wave modules.