| 摘要 |
PURPOSE:To make it possible to make the optimum design of the heat resistance of a FET part and the line width of a microstrip line separately from each other by a method wherein an insulating film is partially formed on the rear of a semiconductor substrate, on which a microwave monolithic integrated circuit is formed, and the apparent thickness of the substrate is changed at the FET part, the periphery of a via hole and a wiring region. CONSTITUTION:An insulating film 4 consisting of (a silicon oxide film 6 and) a polyimide film is formed on the rear of a GaAs substrate la excluding the part, which corresponds to a FET part 2 on the substrate 1a, of the rear and a via hole 3 and thereafter, an Au plating 5 is applied to the whole rear. In such a way, the apparent thickness of the substrate is made thin at the FET part 2 to lessen the heat resistance of the FET part and is made thick at the place of a wiring 7 constituting a microstrip line to inhibit an increase in the characteristic impedance of the wiring. |
