| abstract |
A substrate processing apparatus implements the method of etching a board|substrate. The method includes a first step of etching the substrate to form a first portion of the recess in the substrate. The first portion of the recess includes a bottom surface and a side wall. The method also includes a second process of forming an ammonium silicofluoride AFS layer in or on the sidewall, followed by a third process of etching the bottom surface to form a second portion of the recess. A 3rd process is implemented, maintaining protection of the side wall by an AFS layer. |