Thickness measuring apparatus, thickness measuring method, and wet etching apparatus and wet etching method utilizing them

Abstract

At each measurement time, reflected light from a semiconductor wafer W or the like by measurement light from a measurement light source is coupled to reference light from a reference light generating section and interference light is detected by a photodetector A raw thickness value calculating section selects two light intensity peaks corresponding to the upper and lower surfaces of the wafer W from a light intensity distribution between an interference light intensity and a reference optical path length and calculates a raw thickness value. A statistical thickness value calculating section executes statistical processing including data sorting, determination whether the raw thickness value falls within an allowable numerical value range, and determination of a thickness change line, thereby obtaining a statistical thickness value. With this arrangement, a thickness measuring apparatus and thickness measuring method capable of measuring the thickness of a semiconductor wafer during execution of wet etching independently of the presence of an etchant, and a wet etching apparatus and wet etching method using the thickness measuring apparatus and method are implemented.