Abstract: A process to fabricate a specified height and cross-section of Microwave Monolithic Integrated Circuit gold posts comprising a patterned conductive substrate overlayed by an adhesive layer, a matrix layer, and a photoresist layer. Using photolithographic techniques, gold post locations are defined in the photoresist layer. m Gold post locations and cross-sections are defined in the matrix layer. The adhesive layer at the gold post locations is removed. The gold post locations are plated to form gold posts. The matrix is etched and the adhesive is dissolved.

Abstract: Integration and packaging of monolithic microwave integrated circuits (MMIC) components is facilitated by using a motherboard comprising high resistivity silicon, which having a thermal conductivity three times that of gallium arsenide. Ultra high purity, uncompensated silicon preferably is used. Anisotropic etching of recesses in the motherboard facilitates precise placement of the MMICs in the recesses, enabling use of automated die and wire bonding techniques to reduce required assembly time substantially. Using a silicon motherboard also ultimately enables incorporation of required control circuitry. The silicon motherboard also transmits RF energy well, a useful characteristic particularly in C-band and X-band applications in which microstrip is used, though other transmission media function well at even higher frequencies.