| 摘要 |
PURPOSE: A semiconductor electric condenser microphone assembly is provided to reduce the number of components by installing a semiconductor chip on a printed circuit board. CONSTITUTION: A vibration plate(20) is vibrated by a sound wave. An electric layer(14) is located at a predetermined distance from the vibration plate(20). A semiconductor chip(12) is connected with the electric layer(14) in order to increase a change of capacitance of a condenser by vibration of the vibration plate(20). An FET circuit is patterned in an inside of the semiconductor chip(12) in order to perform an impedance transform. The semiconductor chip(12) is installed on an upper portion of a printed circuit board(10). The electric layer(14) is formed on a bottom face of the printed circuit board(10) by using an electric plating method. A power electrode(12a) and an output electrode(12b) of the FET circuit are formed on the upper portion of the printed circuit board(10). A gate electrode(12c) is connected electrically with the electric layer(14). A plating layer(16) is formed around an edge of the bottom face of the printed circuit board(10). An interval(18) is formed between the plating layer(16) and the electric layer(14). A spacer ring(22) is formed around an edge of a bottom face of the vibration plate(20). The printed circuit board(10) and the vibration plate(20) are fixed by a case(30).
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