Modified channeled spectrum for fast measurement of thin films.
A simple and effective technique for the simultaneous measurement of the refractive index and the thickness of thin films is proposed. The method is based on the spectral dependence of the visibility of interference fringes that result from thin-film interference when the film is illuminated with a white light. The film is on the special substrate, and an optical contact is provided between them. The measurement consists of finding the local change of the fringes' visibility in the observed channeled spectrum expressed as the seaming change of the fringes' periodicity. The method can be applied for real time optical inspection during the manufacturing of thin polymer films.
Dyankov
G
G
Industrial Technology Research Institute, Center for Measurement Standards, Building 12, Section 2, Kuang Fu Road 321, Hsinchu 300, Taiwan. dyankov@itri.org.tw