PLASMA-ENHANCED ETCHING IN AN AUGMENTED PLASMA PROCESSING SYSTEM.

• US 20140054269A1
• Filed: 09/25/2012
• Published: 02/27/2014
• Est. Priority Date: 08/27/2012
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Andrew D. Bailey III
• Inventors: Hudson, Eric A., Bailey, Andrew D. III, Dhindsa, Rajinder
• Granted Patent: US 9,039,911 B2
• Time in Patent Office: Days
• US Class Current: 216/67
• 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 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, comprising:

providing a primary feed gas into said primary plasma generating region;

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

generating a primary plasma from said primary feed gas;

generating a secondary plasma from said secondary feed gas;

etching said substrate using at least said primary plasma and neutral species from said secondary plasma, said neutral species migrating from said secondary plasma generating region to said primary plasma generating region across said semi-barrier structure, said semi-barrier structure but prevents appreciable transfer of charged particles, plasma, from the primary plasma generating region to the secondary plasma generating region.

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

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

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

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

6. The method of claim 5 wherein said 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 said secondary plasma generating region to emphasize dissociation of said secondary feed gas, wherein said secondary feed gas includes at least one of O₂, N₂ and NF₃.

8. The method of claim 7 wherein said 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 said secondary plasma generating region to emphasize dissociation of said secondary feed gas, wherein said secondary feed gas includes at least one of argon and N₂.

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

11. The method of claim 1 further comprising setting input parameters for said secondary plasma generating region to emphasize dissociation of said secondary feed gas, wherein said secondary feed gas includes N₂.

12. The method of claim 9 wherein said primary feed gas includes CO₂.

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

14. A method 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, comprising:

providing a primary feed gas into said primary plasma generating region;

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

generating a primary plasma from said primary feed gas;

generating a secondary plasma from said secondary feed gas;

etching said substrate using at least said primary plasma and neutral species from said secondary plasma, said neutral species migrating from said secondary plasma generating region to said primary plasma generating region across said barrier structure;

thereafter turning off a power source to said primary plasma generating region, thereby inhibiting formation of said primary plasma;

providing another secondary feed gas into said secondary plasma generating region to generate another secondary plasma;

thereafter performing downstream plasma processing on said substrate using species from said another secondary plasma after said species from said another secondary plasma migrates across said barrier structure.

15. The method of claim 14 wherein said etching represents a dielectric etch.

16. The method of claim 15 wherein said another secondary feed gas includes H₂.

17. The method of claim 14 further comprising setting input parameters for said secondary plasma generating region to emphasize dissociation of at least one of said secondary feed gas and said another secondary feed gas.

18. The method of claim 14 wherein said downstream plasma processing represents defluorination.

19. A method 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, comprising:

providing a primary feed gas into said primary plasma generating region;

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

generating a primary plasma from said primary feed gas, said generating said primary plasma employing a capacitively coupling mechanism;

generating a secondary plasma from said secondary feed gas;

etching said substrate using at least said primary plasma and neutral species from said secondary plasma, said neutral species migrating from said secondary plasma generating region to said primary plasma generating region across said semi-barrier structure, said semi-barrier structure but prevents appreciable transfer of charged particles, plasma, from the primary plasma generating region to the secondary plasma generating region.

20. The method of claim 19 wherein said generating said secondary plasma employing a capacitively coupling mechanism.

21. The method of claim 19 wherein said semi-barrier structure includes a set of holes, each hole in said set of holes having a high aspect ratio configured to inhibit the formation of a plasma in said each hole.