REMOVING METHOD FOR PROTECTIVE FILM OF SILICON SUBSTRATE

PURPOSE:To easily remove unnecessary part of a protective film with etchant within a predetermined time by floating a silicon substrate formed with the film on its entire surface in an etchant tank. CONSTITUTION:A silicon substrate 1 formed with a protective film 2 on the entire surface is held at a horizontal position by a plurality of supporting posts 7 stood in the bottom 5a of a water tank 6. Then, when a valve 12 is opened, etchant 9 is poured from an etchant tank in the tank 6. When the poured etchant 9 is gradually increased to reach the position of a liquid surface sensor 10, the valve 12 is closed, and supply of the etchant 9 from the tank is stopped. When the substrate 1 is floated by the surface tension of the etchant 9, a pedestal part 3 of the substrate 1 is etched, and only the film 2 formed on the pedestal 3 is removed. When it is etched for a predetermined time, a timer, etc., is operated to open the valve 12. Accordingly, the etchant 9 is discharged from a pipe 8 in a direction of an arrow, and returned to the tank.