Patent ID: 8486741

Claim:
Process for etching trenches in a structure comprising a support substrate and a multilayer, formed on the substrate, comprising a core layer and coating layers for the definition of wave guides of an integrated optical device, the process comprising: Implementing a selective plasma attack in the multilayer through a masking structure that leaves uncovered areas of the multilayer corresponding to the trenches to be etched asymmetrically; wherein the masking structure is obtained: forming a mask of metallic material on the multilayer that leaves uncovered the areas corresponding to the trenches to be etched; and forming a mask of non-metallic material that leaves uncovered regions comprising a portion of one edge of the mask of metallic material, wherein the one edge is on one of the sides of the areas corresponding to the trenches to be etched; and that leaves covered regions comprising the opposite edge of the mask of metallic material and at least part of the areas corresponding to the trenches to be etched.