Patent ID: 6528428
Filing Date: 2003-03-04
Classification: H01L

Abstract:
A method of forming a dual damascene structure over a substrate, the substrate having a metal layer formed thereon, comprising the steps of:forming a first dielectric layer over the substrate; forming a etching stop layer over the first dielectric layer; forming a second dielectric layer over the etching stop layer; forming a hard mask layer over the second dielectric layer; forming a patterned first photoresist layer on the hard mask layer; removing a portion of the hard mask layer, the second dielectric layer, the etching stop layer and the first dielectric layer by using the patterned first photoresist layer as a mask to form an via opening, wherein a portion of the metal layer is exposed within the via opening; removing the patterned first photoresist layer; forming a conformal third dielectric layer on a sidewall of the via opening and on the hard mask layer; etching a portion of the third dielectric layer to form a dielectric spacer on the sidewall of the via opening, wherein a portion of the third dielectric layer at a bottom of the via opening is removed until a portion of the metal layer is exposed; forming a patterned second photoresist layer on the hard mask layer; removing a portion of the hard mask layer and the second dielectric layer by using the patterned second photoresist layer as a mask to form a trench; removing the patterned second photoresist layer; removing the dielectric spacer; and forming a conductive layer to fill the via opening, whereby the dual damascene structure.