METHODS OF TRIMMING AMORPHOUS CARBON FILM FOR FORMING ULTRA THIN STRUCTURES ON A SUBSTRATE

• US 20090004875A1
• Filed: 06/27/2008
• Published: 01/01/2009
• Est. Priority Date: 06/27/2007
• Status: Abandoned Application

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Ma, Diana Xiaobing, Liu, Wei, Lill, Thorsten B., Shen, Meihua, MacWilliams, Kenneth, Yeh, Wendy H.
• Application Number:
  US12/163,888
• Publication Number:
  US 20090004875A1
• Time in Patent Office: Days
• US Class Current: 438/735
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment

Abstract

Methods for forming an ultra thin structure using a method that includes trimming a mask layer during an etching process are provided. The embodiments described herein may be advantageously utilized to fabricate a submicron structure on a substrate having a critical dimension less than 55 nm and beyond. In one embodiment, a method of forming a submicron structure on a substrate may include providing a substrate having a patterned photoresist layer disposed on a film stack into an etch chamber, wherein the film stack includes at least a hardmask layer disposed on an underlying layer, trimming the photoresist layer to a first predetermined critical dimension, etching the hardmask layer through openings defined by the trimmed photoresist layer, trimming the hardmask layer to a second predetermined critical dimension, and etching the underlying layer through openings defined by the trimmed hardmask layer.

Claims

1. A method of forming a submicron structure on a substrate, comprising:

providing a substrate having a patterned photoresist layer disposed on a film stack into an etch chamber, wherein the film stack includes at least a hardmask layer disposed on a underlying layer;

trimming the photoresist layer to a predetermined critical dimension;

etching the hardmask layer through openings defined by the trimmed photoresist layer;

trimming the hardmask layer to a predetermined critical dimension; and

etching the underlying layer through openings defined by the trimmed hardmask layer.

2. The method of claim 1, wherein trimming the photoresist layer further comprises:

supplying a halogen containing gas to trim the photoresist layer.

3. The method of claim 1, wherein trimming the hardmask layer further comprises:

supplying an oxygen containing gas or a hydrogen gas to trim the hardmask layer.

4. The method of claim 1, wherein etching the hardmask layer further comprises:

etching openings in a capping layer disposed on the hardmask layer defined by the trimmed photoresist layer to expose the underlying hardmask layer.

5. The method of claim 4, wherein etching the capping layer further comprises:

etching the exposed underlying hardmask layer through the openings in the patterned capping layer to a predetermined depth that does not break through the hardmask layer.

6. The method of claim 4, wherein etching the capping layer further comprises:

etching the capping layer using a plasma formed from at least a fluorine-carbon containing gas.

7. The method of claim 5, wherein etching the exposed underlying hardmask layer further comprises:

etching a hardmask layer using a plasma formed from at least an oxygen containing gas and a hydrogen containing gas.

8. The method of claim 4, wherein the capping layer is a dielectric layer selected from a group consisting of silicon oxide, silicon oxynitride, silicon nitride, silicon, silicon carbon and silicon carbon nitride.

9. The method of claim 1, wherein the hardmask layer is an amorphous carbon layer.

10. The method of claim 1, wherein trimming the hardmask layer into the predetermined critical dimension further comprises:

trimming the hardmask layer to a critical dimension less than about 45 nm.

11. The method of claim 1, wherein etching the underlying layer further comprises:

supplying a halogen containing gas that selectively etches the underlying layer over the hardmask layer, wherein the underlying layer is a polysilicon layer.

12. A method of forming a submicron structure on a substrate, comprising:

providing a substrate having a patterned photoresist layer disposed on a film stack into an etch chamber, wherein the film stack includes a thin capping layer and a thick hardmask layer disposed on an underlying layer;

trimming the photoresist layer to a predetermined critical dimension;

etching the capping layer through openings defined in the trimmed photoresist layer to form a patterned capping layer;

partially etching the hardmask layer through the patterned capping layer to a predetermined depth that does not break through the hardmask layer;

removing the remaining patterned capping layer from the hardmask layer;

trimming the hardmask layer to a predetermined critical dimension, wherein the trimming process forms opening in the hardmask layer; and

etching the underlying layer through the openings defined in the trimmed hardmask layer.

13. The method of claim 12, wherein the capping layer is a layer of at least one of silicon oxide, silicon oxynitride, silicon nitride, silicon, silicon carbon or silicon carbon nitride.

14. The method of claim 12, wherein the hardmask layer is an amorphous carbon layer.

15. The method of claim 12, wherein the predetermined depth of the etched hardmask layer is between about 60 percent and about 80 percent of the total thickness of the hardmask layer.

16. The method of claim 12, wherein trimming the hardmask layer into a predetermined critical dimension further comprises:

trimming the hardmask layer to have a critical dimension less than about 45 nm.

17. The method of claim 12, wherein the underlying layer is a polysilicon layer utilized to be as a gate electrode layer.

18. A method of forming a submicron structure on a substrate, comprising:

providing a substrate having a patterned photoresist layer disposed on a film stack into an etch chamber, wherein the film stack includes an amorphous carbon layer disposed on a polysilicon layer;

trimming the photoresist layer to a predetermined critical dimension;

anisotropically etching the amorphous carbon layer through the trimmed photoresist layer to a predetermined depth that does not break through the amorphous carbon layer;

trimming the amorphous carbon layer into a predetermined critical dimension, wherein trimming also forms openings in the amorphous carbon layer;

etching the polysilicon layer through the openings in the trimmed amorphous carbon layer; and

forming a gate structure on the substrate.

19. The method of claim 18, wherein trimming the photoresist layer further comprises:

supplying a first trimming gas mixture having high selectivity to the photoresist layer over the amorphous carbon layer to trim the photoresist layer to a critical dimension less than about 55 nm.

20. The method of claim 19, wherein the first trimming gas further comprises a halogen containing gas.

21. The method of claim 19, wherein trimming the amorphous carbon layer further comprises:

supplying a second trimming gas mixture having high selectivity to the amorphous carbon layer over the polysilicon layer to trim the amorphous carbon layer to a critical dimension less than about 45 nm.

22. The method of claim 19, wherein the second trimming gas includes at least an oxygen containing gas and a hydrogen gas.