Capped modular microwave integrated circuit and method of making same

Abstract

A capped MMIC and method of making same wherein a polymer layer cast over the surface of a semiconductor wafer and vias are formed in the polymer layer down to the wafer surface. The exposed surface of the polymer layer is then metallized and etched in a predetermined pattern to provide a metal pattern over the upper surface of the polymer layer which extends into the vias and to the surface of the wafer. Pads of the metallization are also provided on the upper surface of the polymer layer which are individually electrically isolated from the remainder of the metallization. The wafer is now ground back and backside metallization and other desired processing then takes place in standard manner to complete fabrication of the individual MMICs on the wafer. The MMICs are then diced in standard manner. The MMICs can be secured in a housing fabricated of ceramic or metal. The housing has a plurality of cavities, each cavity for receipt of a MMIC or MMICs. A ground plane is provided along the surface of the housing by plating or the like, if the housing is ceramic (the housing can be its own ground plane if electrically conductive), this ground plane being coupled to the metallization on the MMIC to provide a continuous ground plane along the top surface of the housing with pads on the surface of the MMIC electrically isolated from the ground plane. A multilayer circuit can be fabricated over the ground plane layer and can contain passive elements thereon, such as couplers, filters, transmission lines and the like which are coupled through vias therein to pads on the MMICs.