Patent ID: 6555468
Filing Date: 2003-04-29
Classification: H01L

Abstract:
A method for forming a trench, comprising:forming sequentially a first inter-metal dielectrics (IMD) layer, a mask layer and a second IMD layer on a semiconductor substrate; forming a first photoresist layer on said second IMD layer; performing a photolithography and etching process to transfer a photo mask pattern to form a first opening inside said second IMD layer, wherein said mask layer serves as an etching stop layer; forming a second photoresist layer on said first photoresist layer and inside said first opening; removing a portion of said second photoresist layer to expose a portion of said mask layer within the first opening, and etching said exposed mask layer and said first IMD layer thereunder to form a second opening until said semiconductor substrate is exposed; and stripping said first photoresist layer and said second photoresist layer to form a trench having said first opening and said second opening.