Patent ID: 7126697

Claim:
A method of processing a semiconductor wafer comprising: a step of setting a standard pattern consisting of a time differential value of an interference light for each of multiple wavelengths from a first film to be processed overlying a second film that corresponds to a predetermined film process quantity of the first film; a step of etching a same structure on the semiconductor wafer as the first film overlying the second film, measuring an intensity of an interference light for each of the multiple wavelengths from the first film and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths; a step of determining a remaining thickness of the first film based on the standard pattern consisting of time differential values and the actual pattern consisting of time differential values; and a step of etching the first film remaining after a determination of the thickness of the first film reaching a predetermined value with a changed etching condition during a predetermined time period.