Method and apparatus for stable plasma processing

• US 20060000805A1
• Filed: 06/30/2004
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Todorow, Valentin N., Willwerth, Michael D., Holland, John P.
• Granted Patent: US 8,349,128 B2
• Time in Patent Office: Days
• US Class Current: 216/68
• CPC Class Codes: C23F 1/08 Apparatus, e.g. for photomechanical printing surfaces photo- mechanical reproduction G03F
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32633 Baffles
• CPC Class Codes: H01L 21/67069 for drying etching

Abstract

A method and apparatus for etching a substrate using a spatially modified plasma is provided herein. In one embodiment, the method includes providing a process chamber having a plasma stabilizer disposed above a substrate support pedestal. A substrate is placed upon the pedestal. A process gas is introduced into the process chamber and a plasma is formed from the process gas. The substrate is etched with a plasma having an ion density to radical density ratio defined by the plasma stabilizer.

Claims

1. An apparatus for plasma processing a substrate, comprising:

a process chamber;

a substrate support pedestal disposed therein;

an RF power source for forming a plasma within the chamber; and

a plasma stabilizer disposed in the chamber above the pedestal and adapted to control the spatial distribution of charged and neutral species of the plasma.

2. The apparatus of claim 1, wherein the RF power source is inductively coupled to the process chamber.

3. The apparatus of claim 1, wherein the plasma stabilizer is disposed about 1.25 cm below a ceiling of the process chamber.

4. The apparatus of claim 1, wherein the plasma stabilizer further comprises:

a member electrically isolated from the chamber; and

a plurality of apertures formed through the member.

5. The apparatus of claim 4, wherein the apertures are about 1.25 cm in diameter.

6. The apparatus of claim 4, wherein the member is non-parallel to a substrate support surface of the pedestal.

7. The apparatus of claim 4, wherein the apertures have a hole size, shape, position, and distribution over the surface of the member to define an ion density to radical density ratio proximate the substrate.

8. The apparatus of claim 4, further comprising:

a plurality of support legs supporting the member above the pedestal.

9. The apparatus of claim 8, wherein the legs support the member in a substantially parallel, spaced apart relation with respect to the pedestal.

10. The apparatus of claim 8, further comprising:

an edge ring disposed about a perimeter of an upper surface of the support pedestal and having the plurality of support legs extending therefrom.

11. The apparatus of claim 4, wherein the member is fabricated from at least one of ceramic, quartz, or anodized aluminum.

12. The apparatus of claim 4, wherein the plasma stabilizer is electrically isolated from ground.

13. The apparatus of claim 1, wherein a plasma is formed having an ion density to radical density ratio in a first processing region above the plasma stabilizer that is different from the ion density to radical density in a second processing region below the stabilizer.

14. The apparatus of claim 13, wherein the ion density to radical density ratio is lower in the second processing region.

15. A method of etching, comprising:

providing a process chamber having a substrate support pedestal adapted to receive a substrate thereon and a plasma stabilizer disposed above the pedestal;

placing a substrate upon the pedestal;

introducing a process gas into the process chamber;

forming a plasma from the process gas; and

etching the substrate with a plasma having an ion density to radical density ratio defined by the plasma stabilizer.

16. The method of claim 15, wherein the step of introducing a process gas into the process chamber further comprises:

introducing a gas selected form the group consisting of sulfur hexafluoride, nitrogen trifluoride, carbon tetrafluoride, and hydrogen chloride.

17. The method of claim 15, wherein the step of introducing a process gas into the process chamber further comprises:

introducing sulfur hexafluoride into the process chamber.

18. The method of claim 15, wherein the step of forming a plasma further comprises:

inductively coupling RF power to an antenna disposed proximate the process chamber.

19. The method of claim 15, wherein the step of etching the substrate further comprises:

defining a hole size, shape, position, and distribution over the surface of the plasma stabilizer to control the ion density to radical density ratio proximate the substrate.

20. The method of claim 15, wherein the step of etching the substrate further comprises:

substantially preventing etch by-products from diffusing into a first region of the processing chamber above the plasma stabilizer.

21. A method of etching a layer of tungsten disposed on a substrate, comprising:

providing a process chamber having a substrate support pedestal adapted to receive a substrate thereon and a plasma stabilizer disposed above the pedestal;

placing a substrate upon the pedestal;

introducing sulfur hexafluoride and nitrogen into the process chamber;

forming a plasma from the process gas; and

etching the substrate with a plasma having an ion density to radical density ratio defined by the plasma stabilizer.

22. The method of claim 21, wherein the step of etching further comprises:

controlling the ion density to radical density ratio by controlling an open area percentage of the plasma stabilizer.

23. The method of claim 21, wherein the step of forming a plasma further comprises:

forming a plasma in an area of the processing chamber defined in a first processing region above the plasma stabilizer.

24. The method of claim 23, wherein the plasma stabilizer further comprises:

a member having a plurality of apertures formed therethrough.

25. The method of claim 23, wherein the step of etching the substrate further comprises:

exposing the substrate to a plasma having a first ion density to radical density ratio in an upper processing region of the chamber and a second ion density to radical density ratio in a lower processing region of the chamber.

26. The method of claim 25, wherein the second ion density to radical density ratio is lower than the first ion density to radical density ratio.

27. The method of claim 23, wherein the step of etching the substrate further comprises:

substantially preventing etch by-products from diffusing into the first processing region.

28. An apparatus for plasma etching, comprising:

a process chamber;

a substrate support pedestal disposed in the process chamber;

an RF power source for forming a plasma within the chamber; and

means for controlling the spatial distribution of charged and neutral species of the plasma.

29. A method of etching, comprising:

forming a plasma comprising ions and radicals in a first region of a chamber;

filtering radicals from the plasma; and

etching a substrate predominantly with radicals that are filtered from the plasma.

30. The method of claim 29, wherein the step of filtering radicals further comprises:

forming a plasma having a first ion density to radical density ratio in the first region of the chamber; and

extracting ions from the plasma to form a plasma having a second ion density to radical density ratio in a second region of the chamber.

31. The method of claim 29, further comprising:

substantially preventing etch by-products from diffusing into the first region.