Patent ID: 8409451

Claim:
A method of fabricating a thin-glass substrate, comprising: preparing an apparatus for etching a substrate; and etching a glass substrate containing silicon dioxide as a principal constituent at an etching rate equal to or higher than 2 micrometers per a minute by means of said apparatus, said apparatus comprising: (a) a nozzle system including at least one nozzle through which acid solution containing at least hydrofluoric acid is sprayed onto said substrate; (b) a mover which moves at least one of said nozzle system and said substrate relative to the other in a predetermined direction in such a condition that said substrate and said nozzle system face each other; (c) a filter system which filters off particles out of said acid solution having been sprayed onto said substrate, said filter system 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 system which circulates said acid solution having been sprayed onto said substrate, to said filter system, and further, to said nozzle system from said filter system.