Soft landing nanolaminates for advanced patterning
Methods for depositing nanolaminate protective layers over a core layer to enable deposition of high quality conformal films over the core layer for use in advanced multiple patterning schemes are provided. In certain embodiments, the methods involve depositing a thin silicon oxide or titanium oxide film using plasma-based atomic layer deposition techniques with a low high frequency radio frequency (HFRF) plasma power, followed by depositing a conformal titanium oxide film or spacer with a high HFRF plasma power.
1. A method of processing a semiconductor substrate, the method comprising:
depositing a nanolaminate layer on the substrate; and
depositing a titanium oxide layer on the nanolaminate layer, the nanolaminate layer having a thickness of between about 15 Å and about 200 Å and a density lower than the density of the titanium oxide layer.
2. The method of claim 1 , further comprising depositing an amorphous carbon layer, wherein the nanolaminate layer is deposited on the amorphous carbon layer.
3. The method of claim 2 , wherein the amorphous carbon layer is a patterned layer.
4. The method of claim 1 , wherein the nanolaminate layer comprises a stack comprising two or more sublayers.
5. The method of claim 4 , wherein the two or more sublayers each comprise silicon oxide, or titanium oxide, or combinations thereof.
6. The method of claim 4 , wherein the stack comprises no more than two sublayers.
7. The method of claim 6 , wherein the nanolaminate layer comprises a first sublayer of silicon oxide and a second sublayer of titanium oxide.
8. The method of claim 1 , wherein the nanolaminate layer comprises silicon oxide or titanium oxide.
9. The method of claim 1 , wherein the nanolaminate layer is deposited using plasma-enhanced atomic layer deposition (PEALD) by:
exposing the substrate to a titanium-containing precursor or a silicon-containing precursor;
exposing the substrate to an oxidant; and
initiating a plasma while the substrate is exposed to the oxidant.
10. The method of claim 9 , wherein the nanolaminate layer is deposited at a temperature between about 50° C. and about 150° C. and the plasma is initiated at a high frequency radio frequency (HFRF) power per square millimeter of substrate area between about 1.768×10 −4 W per mm 2 and about 1.768×10 −3 W per mm 2 .
11. The method of claim 9 , wherein the nanolaminate layer is deposited at a temperature less than about 100° C.
12. The method of claim 9 , wherein the titanium-containing precursor comprises TDMAT.
13. The method of claim 1 , wherein the titanium oxide layer is deposited by PEALD by:
exposing the substrate to a titanium-containing precursor;
exposing the substrate to an oxidant; and
initiating a plasma while the substrate is exposed to the oxidant at a HFRF power per square millimeter of substrate area of at least about 1.768×10 −3 W per mm 2 .
14. The method of claim 13 , wherein the oxidant comprises nitrous oxide or oxygen or carbon dioxide or a mixture thereof.
15. The method of claim 13 , wherein the titanium-containing precursor comprises TDMAT.
16. The method of claim 13 , wherein the titanium oxide layer is deposited at a pressure between about 3 Torr and about 3.5 Torr.
17. The method of claim 13 , wherein the titanium oxide layer is deposited at a temperature between about 50° C. and about 400° C.
18. A method of processing a semiconductor substrate, the method comprising:
(a) exposing the substrate to a first titanium-containing precursor or a silicon-containing precursor;
(b) exposing the substrate to a first oxidant;
(c) initiating a first plasma while the substrate is exposed to the first oxidant with a HFRF power per square millimeter of substrate area between about 1.768×10 −4 W per mm 2 and about 1.768×10 −3 W per mm 2 ;
(d) exposing the substrate to a second titanium-containing precursor;
(e) exposing the substrate to a second oxidant; and
(f) initiating a second plasma while the substrate is exposed to the second oxidant with a HFRF power per square millimeter of substrate area of at least about 1.768×10 −3 W per mm 2 .