公开(公告)号：US11469095B2

公开(公告)日：2022-10-11

申请号：US16709251

申请日：2019-12-10

Applicant: STMicroelectronics (Crolles 2) SAS

Inventor： Delia Ristoiu ,  Pierre Bar ,  Francois Leverd

IPC: H01L21/311 ,  H01L21/02 ,  H01L21/67

Abstract: The present disclosure relates to a method for forming a cavity that traverses a stack of layers including a bottom layer, a first portion of which locally presents an excess thickness, the method comprising a first step of non-selective etching and a second step of selective etching vertically in line with the first portion.

公开(公告)号：US10770306B2

公开(公告)日：2020-09-08

申请号：US16240044

申请日：2019-01-04

Applicant: STMicroelectronics (Crolles 2) SAS

Inventor： Pierre Bar ,  Francois Leverd ,  Delia Ristoiu

IPC: H01L21/3065 ,  H01L21/311 ,  H01L21/308 ,  H01L21/02 ,  G02B6/36 ,  G02B6/42

Abstract: A cavity is etched in a stack of layers which includes a first layer made of a first material and a second layer made of a second material. To etch the cavity, a first etch mask having a first opening is formed over the stack of layer. The stack of layers is then etched through the first opening to a depth located in the second layer. A second mask having a second opening, the dimensions of which are smaller, in top view, than the first opening, is formed over the stack of layer. The second opening is located, in top view, opposite the area etched through the first opening. The second layer is then etched through the second opening to reach the first layer. The etch method used is configured to etch the second material selectively over the first material.