Plasma-enhanced etching in an augmented plasma processing system

• US 9,418,859 B2
• Filed: 04/01/2015
• Issued: 08/16/2016
• Est. Priority Date: 08/27/2012
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Hudson, Eric A., Bailey, Andrew D. III, Dhindsa, Rajinder
• Primary Examiner(s): Lu, Jiong-Ping
• Application Number:
  US14/676,711
• Publication Number:
  US 20150206775A1
• Time in Patent Office: 503 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32009 Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01J 37/32458 Vessel
• CPC Class Codes: H01J 37/32715 Workpiece holder
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/67069 for drying etching

Abstract

Methods for etching a substrate in a plasma processing chamber having at least a primary plasma generating region and a secondary plasma generating region separated from said primary plasma generating region by a semi-barrier structure. The method includes generating a primary plasma from a primary feed gas in the primary plasma generating region. The method also includes generating a secondary plasma from a secondary feed gas in the secondary plasma generating region to enable at least some species from the secondary plasma to migrate into the primary plasma generating region. The method additionally includes etching the substrate with the primary plasma after the primary plasma has been augmented with migrated species from the secondary plasma.

Claims

1. A method for etching a substrate in a plasma processing chamber having a semi-barrier structure separating a primary plasma generating region from a secondary plasma generating region, comprising:

providing a primary feed gas to the primary plasma generating region from outside the secondary plasma generating region;

providing a secondary feed gas into the secondary plasma generating region, the secondary feed gas being different from the primary feed gas;

generating a primary plasma from the primary feed gas;

generating a secondary plasma from the secondary feed gas; and

exposing the substrate to species in the primary plasma generating region to etch the substrate,

wherein the semi-barrier structure is configured to allow neutral reactive species to migrate from the secondary plasma generating region to the primary plasma generating region across the semi-barrier structure.

2. The method of claim 1 wherein the etch is a dielectric etch.

3. The method of claim 1 wherein a pressure in the secondary plasma generating region is greater than a pressure in the primary plasma generating region.

4. The method of claim 1 wherein the secondary feed gas is a non-polymer forming gas.

5. The method of claim 1 further comprising setting input parameters for the secondary plasma generating region to emphasize dissociation of the secondary feed gas, wherein the secondary feed gas includes H₂.

6. The method of claim 5 wherein the primary feed gas includes at least one of CF₄, C_xF_y, and CH_xF_y where x and y are integer values.

7. The method of claim 1 further comprising setting input parameters for the secondary plasma generating region to emphasize dissociation of the secondary feed gas, wherein the secondary feed gas includes at least one of O₂, N₂ and NF₃.

8. The method of claim 7 wherein the primary feed gas includes at least one of argon and a fluorocarbon-containing gas.

9. The method of claim 1 further comprising setting input parameters for the secondary plasma generating region to emphasize dissociation of the secondary feed gas, wherein the secondary feed gas includes at least one of argon and N₂.

10. The method of claim 9 wherein the primary feed gas includes at least one of argon, O₂ and a fluorocarbon-containing gas.

11. The method of claim 9 wherein the primary feed gas includes CO₂.

12. The method of claim 1 further comprising setting input parameters for the secondary plasma generating region to emphasize dissociation of the secondary feed gas, wherein the secondary feed gas includes H₂ and wherein the primary feed gas includes N₂.

13. A method for etching a substrate in a plasma processing chamber having a semi-barrier structure separating a primary plasma generating region from a secondary plasma generating region, comprising:

generating a primary plasma from a primary feed gas provided to the primary plasma generating region;

generating a secondary plasma from a first secondary feed gas provided to the secondary plasma generating region, such that neutral species migrate from the secondary plasma generating region to the primary plasma generating region across the semi-barrier structure;

generating a third plasma from a second secondary feed gas provided to the secondary plasma generating region, such that a second species migrates from the secondary plasma generating region to the primary plasma generating region across the semi-barrier structure; and

exposing the substrate to species in the primary plasma generating region to etch the substrate,

wherein the primary feed gas is provided to the primary plasma generating region from outside the plasma processing chamber.

14. The method of claim 13 wherein the etch represents a dielectric etch.

15. The method of claim 13 further comprising setting input parameters for the secondary plasma generating region to emphasize dissociation of at least one of the first secondary feed gas and the second secondary feed gas.

16. The method of claim 13 wherein the etch represents defluorination.