Water Vapor Based Fluorine Containing Plasma For Removal Of Hardmask

• US 20200135554A1
• Filed: 10/10/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Application

• Current Assignee: Mattson Technology, Inc. (Beijing Economic & Technology Development Area), BeiJing E-Town Semiconductor Technology Co., Ltd.
• Original Assignee: Mattson Technology, Inc. (Beijing Economic & Technology Development Area), BeiJing E-Town Semiconductor Technology Co., Ltd.
• Inventors: Hou, Li, Vaniapura, Vijay M., Sahay, Jeyta Anand, Chung, Hua, Meng, Shuang, Ma, Shawming
• Application Number:
  US16/598,423
• Publication Number:
  US 20200135554A1
• Time in Patent Office: Days
• CPC Class Codes: H01J 37/32724 Temperature
• CPC Class Codes: H01J 37/32788 for extracting the material from the process chamber
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/31122 of layers not containing Si, e.g. PZT, Al2O3
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/76865 Selective removal of parts of the layer H01L21/76844 takes precedence

Abstract

Apparatus, systems, and methods for conducting a hardmask (e.g., boron doped amorphous carbon hardmask) removal process on a workpiece are provided. In one example implementation, a method includes supporting a workpiece on a workpiece support in a processing chamber. The method can include generating a plasma from a process gas in a plasma chamber using a plasma source. The plasma chamber can be separated from the processing chamber by a separation grid. The method can include exposing the workpiece to one or more radicals generated in the plasma to perform a plasma strip process on the workpiece to at least partially remove the hardmask layer from the workpiece. The method can include exposing the workpiece to water vapor as a passivation agent during the plasma strip process.

Claims

1. A method for processing a workpiece, the method comprising:

supporting a workpiece on a workpiece support in a processing chamber, the workpiece comprising a hardmask layer;

generating a plasma from a process gas in a plasma chamber using a plasma source, the process gas comprising a fluorine containing gas;

exposing the workpiece to one or more radicals generated in the plasma to perform a plasma strip process on the workpiece to at least partially remove the hardmask layer from the workpiece; and

exposing the workpiece to water vapor as a passivation agent during the plasma strip process.

2. The method of claim 1, wherein the workpiece comprises one or more silicon dioxide layers and one or more silicon nitride layers.

3. The method of claim 1, wherein the plasma chamber is separated from the processing chamber by a separation grid.

4. The method of claim 1, wherein exposing the workpiece to water vapor as a passivation agent comprises introducing water vapor into the plasma chamber as part of the process gas.

5. The method of claim 1, wherein the fluorine containing gas comprises CF₄.

6. The method of claim 1, wherein the fluorine containing gas comprises CH₂F₂.

7. The method of claim 1, wherein the fluorine containing gas comprises CH₃F.

8. The method of claim 1, wherein the process gas comprises an oxygen gas.

9. The method of claim 1, wherein the process gas comprises a nitrogen gas.

10. The method of claim 1, wherein the process gas comprises a hydrogen gas.

11. The method of claim 1, wherein the hardmask is a boron doped amorphous hardmask.

12. The method of claim 1, wherein the hardmask is a titanium nitride hardmask.

13. The method of claim 1, wherein the workpiece comprises a substrate layer.

14. The method of claim 13, wherein the substrate layer comprises tungsten.

15. The method of claim 1, wherein the plasma strip process is implemented for a process period, the process period being in a range of about 30 seconds to about 1200 seconds.

16. The method of claim 1, wherein the plasma strip process is conducted at a process pressure in the processing chamber, the process pressure being in the range of about 300 mT to about 4000 mT.

17. The method of claim 1, wherein the plasma strip is conducted at a source power for an inductively coupled plasma source, the source power being in the range of about 600W to about 5000W.

18. The method of claim 1, wherein the plasma strip process is conducted with the workpiece at a process temperature, the process temperature being in a range of about 25°

C. to about 400°

C.

19. The method of claim 1, wherein exposing the workpiece to water vapor as a passivation agent comprises introducing water vapor into the processing chamber.

20. The method of claim 3, wherein exposing the workpiece to water vapor as a passivation agent comprises introducing water vapor into the processing chamber at a location beneath the separation grid.

21. The method of claim 3, wherein exposing the workpiece to water vapor as a passivation agent comprises introducing water vapor into the processing chamber at a location between a first grid plate and a second grid plate of the separation grid.

22. The method of claim 1, wherein an ash rate of the plasma strip process is about 1500 Angstroms/minute or more.

23. A plasma processing apparatus, comprising:

a processing chamber having a workpiece support, the workpiece support configured to support a workpiece during plasma processing;

a plasma chamber separated from the processing chamber by a separation grid;

an inductively coupled plasma source configured to induce a plasma in a process gas in the plasma chamber;

wherein radicals generated in the plasma pass through the separation grid for exposure to the workpiece during plasma processing;

a water vapor feed line operable to deliver water vapor to one or more of the plasma chamber, the separation grid, and the processing chamber;

wherein the water vapor feed line comprises a temperature regulation system configured to reduce condensation along a delivery path of water vapor from the water vapor feed line.

24. The plasma processing apparatus of claim 23, wherein the temperature regulation system comprises a heat source.