Atomic layer etch methods and hardware for patterning applications

• US 9,997,371 B1
• Filed: 04/28/2017
• Issued: 06/12/2018
• Est. Priority Date: 04/24/2017
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Agarwal, Pulkit, Kumar, Purushottam, LaVoie, Adrien
• Primary Examiner(s): Choudhry, Mohammad
• Application Number:
  US15/582,359
• Time in Patent Office: 410 Days
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking
• CPC Class Codes: G03F 7/405 Treatment with inorganic or organometallic reagents after imagewise removal
• CPC Class Codes: G03F 7/427 using plasma means only
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

Methods and apparatuses for patterning carbon-containing material over a layer to be etched are provided herein. Methods involve trimming carbon-containing material by atomic layer etching including exposing the carbon-containing material to an oxygen-containing gas without a plasma to modify a surface of the carbon-containing material and exposing the carbon-containing material to an inert gas and igniting a plasma to remove the modified surface of the carbon-containing material. Methods may be used for multiple patterning techniques such as double and quad patterning. Methods also include depositing a conformal film over a carbon-containing material patterned using atomic layer etching without breaking vacuum.

Claims

1. A method of processing a semiconductor substrate, the method comprising:

(a) providing to a chamber the semiconductor substrate comprising a carbon-containing material having a pattern of carbon-containing features; and

(b) trimming the carbon-containing features by atomic layer etching to reduce critical dimension and form trimmed carbon-containing features having vertical sidewalls, the atomic layer etching comprising;

(i) exposing a surface of the carbon-containing features to an oxygen-containing gas without a plasma to modify the surface of the carbon-containing features forming a modified surface of the carbon-containing features; and

(ii) exposing the modified surface of the carbon-containing features to an inert gas and igniting a plasma to remove the modified surface of the carbon-containing features.

2. The method of claim 1, wherein the oxygen-containing gas is selected from the group consisting of oxygen and nitrous oxide.

3. The method of claim 1, wherein the inert gas is selected from the group consisting of helium, nitrogen, argon, and combinations thereof.

4. The method of claim 1, wherein the carbon-containing features comprise a material selected from the group consisting of spin-on carbon, photoresist, and amorphous carbon.

5. The method of claim 1, wherein the chamber is set to a chamber pressure between about 1 Torr and about 10 Torr.

6. The method of claim 1, wherein the plasma is ignited using a plasma power between about 50 W and 250 W.

7. The method of claim 1, further comprising purging the chamber between exposing the surface of the carbon-containing features to the oxygen-containing gas without a plasma and exposing the surface of the carbon-containing features to the inert gas and igniting the plasma.

8. The method of claim 7, wherein the chamber is purged for a duration between about 0.1 seconds and about 0.5 seconds.

9. The method of claim 1, wherein the atomic layer etching further comprises repeating (i) and (ii) in cycles.

10. The method of claim 9, wherein between about 5 cycles and about 100 cycles are performed.

11. The method of claim 9, further comprising after forming the trimmed carbon-containing features,

(c) depositing a film conformally over the trimmed carbon-containing features by atomic layer deposition without breaking vacuum.

12. The method of claim 11, wherein (b) and (c) are performed in the same chamber.

13. The method of claim 11, wherein the film deposited conformally comprises material selected from the group consisting of silicon oxide, silicon nitride, silicon carbide, and metal oxides.

14. The method of claim 1, further comprising after providing the semiconductor substrate and prior to trimming the carbon-containing features, heating the substrate to a temperature between about 35°

C. and about 100°

C.

15. The method of claim 1, wherein aspect ratios of the carbon-containing features of the pattern of carbon-containing features on the semiconductor substrate provided to the chamber are between about 6:

1 and about 10;

1.

16. The method of claim 1, wherein exposing the surface of the carbon-containing features to the oxygen-containing gas further comprises introducing a carrier gas selected from the group consisting of helium, nitrogen, argon, and combinations thereof.