Development and Realization of a Doubleface Populated Multichip Module in Thin Film Technology for High Frequency Application

A doubleface populated transmit/receive (TR) multichip module for radar applications has been implemented with multilayer integration technology. The multilayer is designed and fabricated in thin film technology on A1203 ceramic substrates and offers a high order of complexity for high frequency (hf/rf) circuits up to 20 GHz. 100 /spl mu/m striplines with integrated thin film resistors in combination with the dielectric spaced ground layer on the opposite side define the hf layer on top of the substrate. The multilayer logic control unit on the backside consists of three metal layers (ground-, x-, y conductor plane), each seperated by patterned polymeric dielectrics (Polyimide, Benzocyclobutene). This paper describes the necessary technological steps for high performance in thin film technology. Metallization is done in semi-additive technology and the structured dielectric layers are realized with spin coated materials. Through-holes metallization in the substrate allows communication between the two sides and very short interconnections between the GaAs-MMIC's and the logic control unit.