Tin oxide thin film spacers in semiconductor device manufacturing
Thin tin oxide films can be used in semiconductor device manufacturing. In one implementation, a method of processing a semiconductor substrate includes: providing a semiconductor substrate having a plurality of protruding features residing on an etch stop layer material, and an exposed tin oxide layer in contact with both the protruding features and the etch stop layer material, where the tin oxide layer covers both sidewalls and horizontal surfaces of the protruding features; and then completely removing the tin oxide layer from horizontal surfaces of the semiconductor substrate without completely removing the tin oxide layer residing at the sidewalls of the protruding features. Next, the protruding features can be removed without completely removing the tin oxide layer that resided at the sidewalls of the protruding features, thereby forming tin oxide spacers.
1. A method of processing a semiconductor substrate, the method comprising:
(a) providing a semiconductor substrate comprising a plurality of protruding features residing on an etch stop layer material, and an exposed SnO 2 layer in contact with both the protruding features and the etch stop layer material, wherein the SnO 2 layer covers both sidewalls and horizontal surfaces of the protruding features, and wherein the protruding features comprise a material selected from the group consisting of a carbon-containing material and amorphous silicon and the etch stop layer material comprises silicon oxide; and
(b) completely removing the SnO 2 layer from horizontal surfaces of the semiconductor substrate without completely removing the SnO 2 layer residing at the sidewalls of the protruding features, wherein (b) comprises at least one of (i) exposing the semiconductor substrate to a plasma formed in a gas comprising HBr and (ii) exposing the semiconductor substrate to a plasma formed in a gas comprising Cl 2 .
2. The method of claim 1 , wherein (b) comprises etching the SnO 2 such that a ratio of an etch rate of SnO 2 to an etch rate of the material of the protruding features is greater than 1.
3. The method of claim 1 , wherein the protruding features comprise amorphous silicon.
4. The method of claim 1 , wherein the protruding features comprise the carbon-containing material.
5. The method of claim 1 , further comprising:
(a) after (b), completely removing the protruding features, without completely removing the SnO 2 layer that resided at the sidewalls of the protruding features, thereby forming a plurality of SnO 2 spacers on the etch stop layer material.
6. The method of claim 5 , further comprising etching the etch stop layer material to expose an underlying material in a presence of SnO 2 spacers.
7. The method of claim 1 , wherein (b) comprises exposing the semiconductor substrate to a plasma formed in a gas comprising HBr.
8. The method of claim 1 , wherein (b) comprises exposing the semiconductor substrate to a plasma formed in a gas comprising Cl 2 .
9. The method of claim 1 , wherein (b) comprises etching the SnO 2 layer using different etch chemistries consecutively, wherein a later-used etch chemistry has a higher etch selectivity for SnO 2 relative to underlying materials than an earlier-used etch chemistry.
10. The method of claim 1 , further comprising prior to (a): depositing the SnO 2 layer, wherein the depositing comprises sequentially exposing the semiconductor substrate to a tin-containing precursor and an oxygen-containing precursor.
11. The method of claim 10 , wherein the tin-containing precursor is an alkyl-substituted tin amide.
12. The method of claim 10 , wherein the tin-containing precursor is selected from the group consisting of tetrakis(dimethylamino)tin, tetrakis(ethylmethylamino)tin, N 2 , N 3 -di-tert-butyl-butane-2,3-diamino-tin(II), and 1,3-bis (1,2methylethyl)-4,5-dimethyl-(4R, 5R)-1,3,2-diazastannolidin-2-ylidine.
13. The method of claim 10 , wherein the tin-containing precursor is tetrakis(dimethylamino)tin.
14. A method of processing a semiconductor substrate, the method comprising:
(a) providing a semiconductor substrate comprising a plurality of protruding features residing on an etch stop layer material, and an exposed SnO 2 layer in contact with both the protruding features and the etch stop layer material, wherein the SnO 2 layer covers both sidewalls and horizontal surfaces of the protruding features; and
(b) completely removing the SnO 2 layer from horizontal surfaces of the semiconductor substrate without completely removing the SnO 2 layer residing at the sidewalls of the protruding features, wherein (b) comprises etching the SnO 2 layer using different etch chemistries consecutively, wherein a later-used etch chemistry has a higher etch selectivity for SnO 2 relative to underlying materials than an earlier-used etch chemistry.
15. The method of claim 14 , wherein the later used etch chemistry is characterized by an etch selectivity of greater than 1 for tin oxide etch versus a material of the protruding features.
16. The method of claim 14 , wherein the earlier used etch chemistry comprises a plasma formed in a gas comprising Cl 2 .
17. The method of claim 14 , wherein the later used etch chemistry comprises a plasma formed in a gas comprising HBr.