Patent ID: 9443741
Filing Date: 2016-09-13
CPC Classification: H01L

Claim Text:
1. An etching method comprising: providing a substrate having a high density structure and a low density structure thereon; forming a first material layer covering and contacting the high density structure and the low density structure, wherein part of the low density structure is exposed through the first material layer; forming a second material layer covering the high density structure and the low density structure and contacting the low density structure exposed through the first material layer; etching the second material layer to remove the second material layer on the high density structure and to remove part of the second material layer on the low density structure; etching the first material layer on the high density structure and the second material layer on the low density structure simultaneously; etching the first material layer on the high density structure and on the low density structure to expose a first portion of the high density structure and a second portion of the low density structure; and removing the first portion and the second portion.