| 摘要 |
PROBLEM TO BE SOLVED: To provide an etching method for a wafer which can be compatible the shortening of etching time with the equalization of the enough thickness of the thin part with in a wafer face. SOLUTION: A silicon wafer 3 is etched from one side in condition that the silicon wafer 3 having PN junction is soaked in KOH aqueous solution, thus a part of region of the silicon wafer 3 is etched by a specified quantity, and also a part of etching processing face reaches the PN junction face before all etching processing faces within the wafer face reaches the PN junction face, by injecting and diluting and cooling solution at lower temperature and in lower concentration than the KOH aqueous solution within a processing vessel 55 when the gradient of the current flowing in the silicon wafer 3 becomes large at the time of stopping the etching by the anode oxidation of the silicon in the vicinity of PN junction.
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