Thickness measuring device, the thickness measuring method and wet etching apparatus and wet etching process thus

摘要

At each measuring time, a measuring light from a measuring light source (11) reflected from a semiconductor wafer (W) is combined with a reference light from a reference light generating section (14), and the interference light detected by a photodetector (15). A calculated thickness calculating section (16b) calculates a calculated thickness value by selecting two light intensity peaks corresponding to the upper and lower surfaces of the wafer (W) from the light intensity distribution of the intensity of interference light and the optical path length. A statistic thickness value calculating section (16c) determines a statistic thickness value by performing statistic processings including data selection, judgment if the calculated thickness is in an allowable value range, and determination of thickness variation line. A method and an apparatus for measuring the thickness of a semiconductor wafer during wet etching regardless of presence of etching liquid are realized along with a wet etching apparatus and a wet etching method utilizing them.