| abstract |
A metal base circuit board excellent in heat dissipation is provided by significantly reducing malfunction of a semiconductor generated during high frequency operation of a hybrid integrated circuit. A metal used in a hybrid integrated circuit comprising a circuit formed on the metal plate via insulating layers A and B, an output semiconductor mounted on the circuit, and a control semiconductor formed on the circuit by controlling the output semiconductor. As the base circuit board, a low capacitance portion is embedded in a lower portion of a circuit portion (pad portion) on which the control semiconductor is mounted. Preferably, the low capacitance portion is an inorganic filler. Said metal base circuit board | substrate which consists of resin which consists of containing, and whose dielectric constant is 2-9. |