Spacer patterning process with flat top profile
A method for spacer patterning includes performing a deposition process, the deposition process comprising conformally depositing an over layer over a spacer layer as deposited on top surfaces of a patterned mandrel layer and on sidewalls of the patterned mandrel layer, and performing an etch process using a fluorine containing etching gas. The etch process includes a post-deposition breakthrough process, removing portions of the over layer on the top surfaces of the patterned mandrel layer, and a main-etch process, removing shoulder portions of the over layer and shoulder portions of the spacer layer.
1 . A method for spacer patterning, the method comprising:
performing a deposition process, the deposition process comprising conformally depositing an over layer over a spacer layer as deposited on top surfaces of a patterned mandrel layer and on sidewalls of the patterned mandrel layer;
performing a first etch process using a fluorine containing etching gas, the first etch process comprising:
a post-deposition breakthrough process removing the over layer from the top surfaces of the patterned mandrel layer; and
a main etch process removing shoulder portions of the over layer and shoulder portions of the spacer layer; and
performing a second etch process, the second etch process comprising removing the patterned mandrel layer and the remaining over layer simultaneously with the patterned mandrel layer or after the patterned mandrel layer is removed.
2 . The method of claim 1 , wherein the deposition process, the first etch process, and the second etch process are performed in an inductively coupled plasma (ICP) etch chamber without vacuum break.
3 . The method of claim 1 , wherein the spacer layer comprises silicon nitride.
4 . The method of claim 1 , wherein the patterned mandrel layer comprises a carbon containing material.
5 . The method of claim 1 , wherein the over layer comprises silicon oxide.
6 . The method of claim 1 , wherein the fluorine containing etching gas comprises fluoromethane (CH 3 F).
7 . The method of claim 1 , wherein the second etch process comprises a dry plasma etch process.
8 . A processing system, comprising:
a processing chamber; and
a system controller configured to cause the processing system to:
perform a deposition process, the deposition process comprising conformally depositing an over layer over a spacer layer as deposited on top surfaces of a patterned mandrel layer and on sidewalls of the patterned mandrel layer;
perform a first etch process using a fluorine containing etching gas, the first etch process comprising:
a post-deposition breakthrough process removing the over layer from the top surfaces of the patterned mandrel layer; and
a main etch process removing shoulder portions of the over layer and shoulder portions of the spacer layer; and
perform a second etch process, the second etch process comprising removing the patterned mandrel layer and the remaining over layer simultaneously with the patterned mandrel layer or after the patterned mandrel layer is removed.
9 . The processing system of claim 8 , wherein
the processing chamber is an inductively coupled plasma (ICP) etch chamber, and
the first etch process, and the second etch process are performed without vacuum break.
10 . The processing system of claim 8 , wherein the spacer layer comprises silicon nitride.
11 . The processing system of claim 8 , wherein the patterned mandrel layer comprises a carbon containing material.
12 . The processing system of claim 8 , wherein the over layer comprises silicon oxide.
13 . The processing system of claim 8 , wherein the fluorine containing etching gas comprises fluoromethane (CH 3 F).
14 . The processing system of claim 8 , wherein the second etch process comprises a dry plasma etch process.