Highly integrated three-dimensional MMIC technology applied to novel masterslice GaAs- and Si-MMIC's

A novel three-dimensional (3-D) masterslice monolithic microwave integrated circuit (MMIC) is presented that significantly reduces turnaround time and cost for multifunction MMIC production. This MMIC incorporates an artificial ground metal for effective selection of master array elements on the wafer surface, resulting in various MMIC implementations on a master-arrayed footprint in association with thin polyimide and metal layers over it. Additionally, the 3-D miniature circuit components of less than 0.4 mm ² in size provide a very high integration level. To clearly show the advantages, a 20-GHz-band receiver MMIC was implemented on a master array with 6 × 3 array units including a total of 36 MESFET's in a 1.78 × 1.78 mm area. Details of the miniature circuit components and the design, closely related to the fabrication process, are also presented. The receiver MMIC exhibited a 19-dB conversion gain with an associated 6.5-dB noise figure from 17 to 24 GHz and an integration level four times higher than conventional planar MMIC's. This technology promises about a 90% cost reduction for MMIC because it can be similarly applied to large-scale Si wafers with the aid of an artificial ground.