Film Thickness Monitor
Original Publication Date: 1978-Jan-01
Included in the Prior Art Database: 2005-Feb-20
Transparent film coatings over large areas often possess a surface texture or ripple. This is commonly observed in photoresist films which are applied by spray or roller coating methods. The measurement of the thickness of these films using conventional optical techniques must be limited to small spot locations such that the thickness does not vary beyond a few hundred angstroms within the area being measured. The existence of such local thickness variations can be exploited to determine the film thickness in the following way.