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US 5,853,602 AGranted
Method of dry etching for patterning refractory metal layer improved in etching rate, anisotropy and selectivity to silicon oxide
AssigneeNEC Corporation
InventorHideyuki Shoji
Life of this patent
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Abstract
A refractory metal layer on a silicon oxide layer is exposed to gaseous etchant containing SF.sub.6, Cl.sub.2 and CO so as to be patterned; F radical and Cl radical effectively etch the refractory metal, and a reaction product of CO gas does not allow the dry etching to sidewardly proceed so that the dry etching achieves good anisotropy, a large etching rate and a large selectivity to silicon oxide.
Claims11
A method of dry etching for a refractory metal layer, comprising the steps of:
- a) preparing a multi-layer structure having a refractory metal layer;
- b) patterning a photo-resist layer on said refractory metal layer into a photo-resist etching mask;
- and
- c) exposing said refractory metal layer to a gaseous etchant containing SF.sub.6, Cl.sub.2 and CO effective to etch said refractory metal layer, wherein a reaction product layer produced from said CO prevents a part of said refractory metal layer located under said photo-resist etching mask from radicals produced from said SF.sub.6 and said Cl.sub.2.
1 more element
A method of dry etching for a refractory metal layer, comprising the steps of:
- a) preparing a multi-layer structure having a refractory metal layer;
- and
- b) exposing said refractory metal layer in a reaction chamber to a gaseous etchant containing SF.sub.6, Cl.sub.2 and CO effective to etch said refractory metal layer, wherein said gaseous etchant is introduced into said reaction chamber at a flow rate ratio between SF.sub.6, Cl.sub.2 and CO of 20:0.5-1.5:2-10, respectively.
Dependencies are inferred from the claim text.