| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacitor microphone which is improved in characteristics by properly regulating the internal stress of a diaphragm and further improving the thickness accuracy of the diaphragm. SOLUTION: This manufacturing method comprises a step of providing a recess of prescribed depth to the rear of a single crystal silicon substrate 101 of (100) plane orientation, a step of forming a doping mask corresponding to a back plate on the front surface of the silicon substrate 101, a step of selectively doping the exposed silicon surface of the silicon substrate 101 with boron of high concentration, a step of doping the bottom of the recess with boron of high concentration, and a step of dry-etching the silicon substrate from above the front surface and then etching it with alkaline solution.
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