Patent ID: 7823595

Claim:
An apparatus for etching a substrate, comprising: (a) a nozzle mechanism including at least one nozzle through which an acid solution containing at least hydrofluoric acid is sprayed onto said substrate; (b) a mover which moves at least one of said nozzle mechanism and said substrate relative to the other in a predetermined direction in such a condition that said substrate and said nozzle mechanism face each other; (c) a filter mechanism which filters off particles out of said acid solution that has been sprayed onto said substrate, said filter mechanism including: a container which temporarily contains said acid solution before said acid solution is supplied to said nozzle mechanism after said acid solution was sprayed onto said substrate; a rotator which produces vortex in said acid solution in said container; and a particle collector which collects particles precipitating at an inner edge of said container; and (d) a circulation mechanism which circulates said acid solution sprayed onto said substrate to said filter mechanism, and further, to said nozzle mechanism from said filter mechanism.