| 摘要 |
PURPOSE:To obtain uniform silicon film thickness and silicon groove depths even if depths to be etched vary by a method wherein, when a P-N junction wafer is etched by electrochemical etching, the silicon film thickness and groove depths are controlled by varying the values of applied voltage. CONSTITUTION:Both sides of a silicon wafer 3, consisting of a P-type layer 1 and an N-type layer 2, are covered with oxide films 4. The regions of the oxide film 4 on the side of the P-type layer 1 which are to be diaphragm film parts are removed by photolithograph technology. After the part of the oxide film 4 on the side of the N-type layer 2 where an anode electrode is to be connected is removed, the anode electrode is connected and sealed with silicon resin or the like. The anode of a constant-voltage source 5' is connected to the N-type layer 2 of the silicon substrate 3 and the cathode is connected to a platinum electrode 6. Anisotropic material such as KOH, EDA or hydrazine is employed as etchant. With this constitution, even if an N-type epitaxial substrate with an uniform thickness is employed, a silicon diaphragm with arbitrary thickness can be obtained by predetermining values of applied voltage properly. |
