Patent ID: 7663760

Claim:
A method for calculating optical constants of a plurality of films layered on a substrate, wherein the optical constant of at least one underlayer film among the plurality of the films changes while the plurality of films are layered, comprising: calculating the optical constant of an underlayer film of each of the plurality of films when said each of the films is removed and said underlayer film is exposed after the plurality of films are layered; wherein the plurality of films include a nitride film, an organic insulation film, an oxide film, an antireflection film, and a photoresist film, which are layered in this order, the photoresist film having an opening portion thereof through which a part of the antireflection film is exposed, and wherein the method further comprises: calculating in advance optical constants of a nitride film and an oxide film each formed as a single film on the substrate; measuring a first reflectivity of the photoresist film and a second reflectivity of the exposed part of the antireflection film after the plurality of films are layered; measuring a third reflectivity of the organic insulation film after the exposed part of the antireflection film and the oxide film are removed using a plasma; measuring a fourth reflectivity of the oxide film after the photoresist film and the antireflection film are removed; calculating the optical constant of the organic insulation film based on the fourth reflectivity and the calculated optical constants of the nitride film and the oxide film; calculating the optical constant of the organic insulation film based on the third reflectivity and the calculated optical constants of the nitride film and the organic insulation film; calculating the optical constant of the antireflection film based on the second reflectivity and the calculated optical constants of the nitride film, the oxide film, and the organic insulation film; and calculating with a substrate processing system the optical constant of the photoresist film based on the first reflectivity and the calculated optical constants of the nitride film, the oxide film, the organic insulation film, and the antireflection film.