A plurality of semiconductor devices (5) are formed on a semiconductor wafer (1). A film thickness measurement wiring pattern (3,4) is formed on a dicing line (6,7) defining the plurality of semiconductor devices (5). An SOG film (10) is formed on the semiconductor devices (5) and the film thickness measurement wiring pattern (3,4). A film thickness of the SOG film (10) at a central part of the film thickness measurement wiring pattern (3,4) is measured. The film thickness measurement wiring pattern (3,4) is a rectangular pattern having long sides parallel to the dicing line (3,4).