Apparatus for atomic layering etching

• US 10,014,192 B2
• Filed: 12/11/2013
• Issued: 07/03/2018
• Est. Priority Date: 07/20/2011
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Singh, Harmeet
• Primary Examiner(s): Zervigon, Rudy
• Application Number:
  US14/103,688
• Publication Number:
  US 20150206774A1
• Time in Patent Office: 1,665 Days
• Field of Search: 15634525, 15634526, 15634538, 15634539, 1563454, 118723 R
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/3244 Gas supply means
• 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 37/32633 Baffles
• CPC Class Codes: H01J 37/32715 Workpiece holder
• CPC Class Codes: H01J 37/32899 Multiple chambers, e.g. cluster tools
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors

Abstract

A substrate processing system having a processing chamber for etching a layer on a substrate is provided. The system includes a chuck upon which the substrate is disposed during etching. The system also includes the chamber being divided into a plasma generating region and a substrate processing region by a separating plate structure. The system further includes a plasma source for generating plasma in the plasma generating region. The system further includes logic for introducing a first gas into the chamber, wherein the gas is suitable for etching the layer. The logic also allows the first gas to be present in the chamber for a period of time sufficient to cause adsorption of at least some of the first gas into the layer. The logic further replaces the first gas with an inert gas, generates metastables from the inert gas, and etches the layer with the metastables.

Claims

1. A substrate processing system having a substrate processing chamber for etching a layer on a substrate, comprising:

a substrate support configured to support a substrate in said substrate processing system;

a separating plate structure separating said substrate processing system into a plasma generating region and a substrate processing region, wherein said separating plate structure has a set of holes configured to permit at least some neutral metastables to migrate through said separating plate structure without colliding with the separating plate structure but substantially prevent energetic plasma species from migrating through the separating plate structure, and wherein the separating plate structure is grounded, wherein the separating plate structure, comprises;

a top plate, wherein the top plate is grounded, and

a bottom plate between the top plate and the substrate support;

a plasma source for generating a plasma in said plasma generating region; and

a microprocessor, microcontroller, or computer with logic for;

introducing a first gas into said substrate processing system, said gas being an etchant gas suitable for etching said layer,

allowing said first gas to be present in said substrate processing system for a period of time sufficient to cause adsorption of at least some of said first gas into said layer,

substantially replacing said first gas in said substrate processing system with an inert gas,

generating neutral metastables from said inert gas within said substrate processing region; and

etching said layer in said substrate processing region with said neutral metastables;

wherein said neutral metastables comprise atoms in an excited state.

2. The substrate processing system of claim 1 wherein said metastables are generated by forming a plasma within said substrate processing region from said inert gas using said plasma source.

3. The substrate processing system of claim 2 wherein said metastables traverse said separating plate structure while migrating from said plasma to said layer.

4. The substrate processing system of claim 3 wherein said separating plate structure has a plurality of holes configured for substantially, preventing migration of plasma charged species to said layer.

5. The substrate processing system of claim 3 wherein said top plate and bottom plate are electrically insulated from one another, said top plate and bottom plate having different voltage potentials selected to repel ions emanating from the plasma.

6. The substrate processing system of claim 3 further comprising a collimator plate, wherein said metastables also traverse said collimator plate while migrating from said plasma to said layer, wherein said collimator plate is disposed between said substrate and said separating plate structure.

11. The substrate processing system of claim 3 further comprising moving at least one of said separating plate and said substrate relative to one another during said etching with said metastables.

12. The substrate processing system of claim 1 wherein said etchant gas contains at least a halogen and said layer contains Si.

13. The substrate processing system of claim 1 wherein said period of time is between about 0.05 second to about 180 seconds.

14. The substrate processing system of claim 1 wherein said generating said metastables is performed after at least about 90% of said first gas in said chamber is replaced with said inert gas.

20. The system of claim 1, wherein the excited state of an atom of the metastables carries an energy, delivered to said layer, that is greater than a thermal kinetic energy imparted by the atom to said layer.

21. The substrate processing system of claim 1 wherein said separating plate structure has a plurality of holes configured for preventing migration of at least 60% of plasma charged species from reaching said layer.

22. The substrate processing system of claim 1 wherein said separating plate structure has a plurality of holes configured for preventing migration of at least 95% of plasma charged species from reaching said layer.

7. A substrate processing system having a substrate processing chamber for etching a layer on a substrate, said substrate disposed on a chuck within said chamber during said etching, comprising:

a separating plate structure separating said chamber into a plasma generating region and a substrate processing region, wherein said separating plate structure is grounded and configured with a set of aligned holes sized to permit neutral metastables to migrate through said separating plate structure but substantially prevent energetic plasma species from migrating through the separating plate structure, wherein said neutral metastables comprise atoms in an excited state, wherein the separating plate structure, comprises;

a top plate, wherein the top plate is grounded, and

a bottom plate between the top plate and the substrate support;

a plasma source for generating a plasma in said plasma generating region; and

a microprocessor, microcontroller, or computer with logic for;

introducing a first gas into said chamber, said gas being an etchant gas suitable for etching said layer,

allowing said first gas to be present in said chamber for a period of time sufficient to cause adsorption of at least some of said first gas into said layer,

substantially replacing said first gas in said plasma processing region with an inert gas,

generating a plasma from said inert gas in said plasma generating region, and

etching said layer with neutral metastables from said plasma, wherein said etching is performed while substantially preventing migration of plasma charged species from said plasma to said layer.

8. The substrate processing system of claim 7 wherein said separating plate structure has a plurality of holes configured for substantially preventing migration of plasma charged species to said layer.

9. The substrate processing system of claim 7 wherein said top plate and bottom plate are electrically insulated from one another, said top plate and bottom plate having different voltage potentials selected to repel ions emanating from the plasma.

10. The substrate processing system of claim 7 further comprising a collimator plate, wherein said metastables also traverse said collimator plate while migrating from said plasma to said layer, wherein said collimator plate is disposed between said substrate and said separating plate structure.

15. A substrate processing system having a substrate processing chamber for etching a layer on a substrate, said substrate processing chamber having a plasma generating region and a substrate processing region, said plasma generating region being separated from said substrate processing region by a separating plate structure, comprising:

a separating plate structure separating said chamber into a plasma generating region and a substrate processing region, wherein said separating plate structure is grounded and configured with a set of aligned holes sized to permit neutral metastables to migrate through said separating plate structure but substantially prevent energetic plasma species from migrating through the separating plate structure, wherein said neutral metastables comprise atoms in an excited state, wherein the separating plate structure, comprises;

a top plate, wherein the top plate is grounded, and

a bottom plate between the top plate and the substrate support;

a plasma source for generating a plasma in said plasma generating region; and

a microprocessor, microcontroller, or computer with logic for;

introducing a first gas into said substrate processing region of said chamber, said first gas being an etchant gas suitable for etching said layer,

introducing an inert gas into said plasma generating region,

allowing said first gas to be present in said substrate processing region of said chamber for a period of time sufficient to cause adsorption of at least some of said first gas into said layer while maintaining a pressure of said inert gas in said plasma generating region is greater than a pressure of said etchant gas in said substrate processing region,

replacing at least 80% of said first gas in said substrate processing region of said chamber with said inert gas after said period of time expires,

generating plasma in said plasma generating region of said chamber to generate metastables from said inert gas, and

etching said layer with said metastables while maintaining a pressure in said substrate processing region below 10 mTorr.

16. The substrate processing system of claim 15 wherein said metastables traverse said separating plate structure while migrating from said plasma to said layer.

17. The substrate processing system of claim 16 wherein said metastables also traverse a collimator plate while migrating from said plasma to said layer, wherein said collimator plate is disposed between said substrate and said separating plate structure.

18. The substrate processing system of claim 15 wherein said separating plate structure has a plurality of holes configured for preventing migration of at least 60% of plasma charged species generated in said plasma generating from reaching said layer.

19. The substrate processing system of claim 15 wherein said top plate and bottom plate are electrically insulated from one another, said top plate and bottom plate having different voltage potentials during said etching selected to repel ions emanating from the plasma.