METHOD FOR MEASURING FILM THICKNESS OF PRINTED WIRING BOARD AND OBJECT TO BE MEASURED FOR FILM THICKNESS MEASUREMENT

PROBLEM TO BE SOLVED: To measure a film thickness with accuracy by burying a printed wiring board with a transparent film formed on its surface in synthetic resin mixed and colored with pigment, hardening the resin, thereafter polishing the printed wiring board together with the burying resin to expose the cross section of the board, then measuring the film thickness. SOLUTION: A board 11 with a transparent film 12 formed on its surface by application is placed in a container, and is buried in two-liquid mixed thermosetting synthetic resin (burying resin) 15, such as epoxy resin, mixed with a hardening agent 14 and colored with pigment 16. In this state the burying resin 15 is hardened, and the material formed by burying and securing the board 11 in the resin is taken as an object A to be measured. Thereafter, the object A to be measured is polished to expose the cross section of the board, and the thickness (t) of the film 12 is measured under a microscope. Since the burying resin 15 covering the transparent film 12 is colored, the boundary (f) between them is sharply visible, and the film thickness (t) can be measured with accuracy.