Methods for patterning a layer of a semiconductor device
A patterning layer of a single or multiple layer structure formed on a lower layer may be etched to form one or more steps therein, when the patterning layer is first dry etched to a partial depth thereof using a first resist pattern and then the patterning layer is etched again using a second resist pattern formed by lateral etching of the first resist pattern.
1 . A method for patterning a layer of a semiconductor device, comprising:
forming a lower layer on a substrate;
forming a patterning layer on the lower layer;
forming a resist on the patterning layer;
forming a first resist pattern by performing a lithographic process on the resist;
partially dry etching the patterning layer using the first resist pattern as a mask such that the lower layer is not exposed;
forming a second resist pattern by dry etching a lateral side of the first resist pattern; and
dry etching the patterning layer using the second resist pattern such that the lower layer is exposed.
2 . A method as defined in claim 1 , wherein the patterning layer is a mask layer used for at least partially etching the lower layer.
3 . A method as defined in claim 1 , wherein the patterning layer comprises silicon oxide or polysilicon.
4 . A method as defined in claim 1 , wherein oxygen is a main etchant gas for dry etching the lateral side of the first resist pattern.
5 . A method as defined in claim 4 , wherein an additional gas different from the main etchant gas is used to improve uniformity of the lateral etching of the first resist pattern.
6 . A method as defined in claim 5 , wherein the additional gas is one selected from a group consisting of argon, helium, and nitrogen.
7 . A method for patterning a layer of a semiconductor device, comprising:
forming a lower layer on a substrate;
sequentially forming first and second patterning layers on the lower layer;
forming a resist on the patterning layers;
forming a first resist pattern by performing a lithographic process on the resist;
dry etching the second patterning layer using the first resist pattern as a mask;
forming a second resist pattern by dry etching a lateral side of the first resist pattern; and
dry etching the first and second patterning layers using the second resist pattern as a mask.
8 . A method as defined in claim 7 , wherein oxygen is used as a main etchant gas for dry etching the lateral side of the first resist pattern.
9 . A method as defined in claim 8 , wherein an additional gas different from the main etchant gas is used to improve uniformity of the lateral etching of the first resist pattern.
10 . A method as defined in claim 9 , wherein the additional gas is one selected from a group consisting of argon, helium, and nitrogen.
11 . A method as defined in claim 7 , wherein a third patterning layer is formed on the lower layer prior to the first and second patterning layers.
12 . A method as defined in claim 11 , further comprising:
forming a third resist pattern by dry etching a lateral side of the second resist pattern; and
dry etching the first, second, and third patterning layers using the third resist pattern as a mask.