Patent ID: 6686293
Filing Date: 2004-02-03
Classification: H01L

Abstract:
A method of etching a trench overlying a contact via in a silicon-containing low k dielectric material, in the absence of a trench etch stop layer, comprising:a) exposing said silicon-containing low k dielectric material to a plasma generated from a source gas comprising a fluorine-containing etchant gas and an additive gas selected from the group consisting of carbon monoxide (CO), an inert gas, and combinations thereof, wherein a volumetric flow ratio of said additive gas to said fluorine-containing etchant gas is within the range of about 1.25:1 to about 20:1, and wherein said fluorine-containing etchant gas is selected from the group consisting of a fluorocarbon gas having a fluorine:carbon ratio of at least 3:1, SF6, NF3, and combinations thereof; and b) etching said trench in said silicon-containing low k dielectric material to a nominal trench depth in the absence of a trench etch stop layer.