METHOD OF SLIMMING RADIATION-SENSITIVE MATERIAL LINES IN LITHOGRAPHIC APPLICATIONS

• US 20110244403A1
• Filed: 03/31/2011
• Published: 10/06/2011
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Rathsack, Benjamin M., Somervell, Mark H., Carcasi, Michael A.
• Granted Patent: US 8,435,728 B2
• Time in Patent Office: Days
• US Class Current: 430/326
• CPC Class Codes: G03F 7/2024 of the already developed image
• CPC Class Codes: G03F 7/32 Liquid compositions therefor, e.g. developers
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking
• CPC Class Codes: H01L 21/0273 characterised by the treatment of photoresist layers
• CPC Class Codes: H01L 21/0274 Photolithographic processes
• CPC Class Codes: H01L 21/67207 comprising a chamber adapted to a particular process

Abstract

A method and system for patterning a substrate using a radiation-sensitive material is described. The method and system include forming a layer of radiation-sensitive material on a substrate, exposing the layer of radiation-sensitive material to a pattern of radiation, and then performing a post-exposure bake following the exposing. The imaged layer of radiation-sensitive material is then developed to remove either a region having high radiation exposure or a region having low radiation exposure to form radiation-sensitive material lines. An exposure gradient within the radiation-sensitive material lines is then removed, followed by slimming the radiation-sensitive material lines.

Claims

1. A method of patterning a substrate comprising:

forming a layer of radiation-sensitive material on a substrate;

exposing said layer of radiation-sensitive material to a pattern of radiation, wherein said pattern includes;

a first region having a high radiation exposure,

a second region having a low radiation exposure, and

a third region having an exposure gradient ranging from about said high radiation exposure to about said low radiation exposure;

performing a post-exposure bake following said exposing;

performing positive-tone developing by contacting said layer of radiation-sensitive material with a first organic solvent-based composition to remove said first region from said substrate to provide a developed layer of radiation-sensitive material;

removing said exposure gradient of said third region by transforming said second region and said third region to a fourth region having a substantially uniform level of radiation exposure, polarity, or de-protection, or a combination thereof; and

slimming said fourth region.

2. The method of claim 1, wherein said layer of radiation-sensitive material comprises:

a hydrophilic polymer that decreases in polarity upon performing

said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material,

an acid wash and a post-acid wash bake of said layer of radiation-sensitive material,

a heating of said layer of radiation-sensitive material to a temperature equal to or greater than a thermal decomposition temperature of said radiation-sensitive material, or

any combination of two or more thereof;

or

an acid generator that provides acid-catalyzed rearrangement of the hydrophilic polymer to a more hydrophobic polymer upon performing

said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material;

said acid wash and said post-acid wash bake of said layer of radiation-sensitive material;

said heating of said layer of radiation-sensitive material to said temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material, or

any combination of two or more thereof.

3. The method of claim 1, wherein said removing said exposure gradient comprises:

performing a flood exposure and a post-flood exposure bake of said developed layer of radiation-sensitive material;

performing an acid wash and a post-acid wash bake of said developed layer of radiation-sensitive material;

or

heating said developed layer of radiation-sensitive material to a temperature equal to or greater than a thermal decomposition temperature of said radiation-sensitive material.

4. The method of claim 3, wherein said slimming said fourth region comprises

contacting said fourth region with a second organic solvent-based composition at an ultra-cold temperature to remove a portion of said fourth region, wherein said ultra-cold temperature is less than 25°

C. and greater than a freezing point of said second organic solvent-based composition.

5. The method of claim 3, wherein said slimming said fourth region comprises contacting said fourth region with a second organic solvent-based composition to remove a portion of said fourth region, wherein said second organic solvent-based composition achieves a rate of a dissolution ranging from about 0.1 nm/sec to about 5 nm/sec.

6. The method of claim 3, wherein said slimming said fourth region comprises contacting said fourth region with an aqueous base solution to remove a portion of said fourth region.

7. The method of claim 3, wherein said slimming said fourth region comprises contacting said fourth region with an aqueous solution comprising a promoting agent to remove a portion of said fourth region.

8. The method of claim 7, wherein the promoting agent is a salt comprising an alkali metal.

9. The method of claim 3, wherein said slimming said fourth region comprises contacting said fourth region with an aqueous base solution at a temperature ranging from about 30°

C. to about the boiling point of the aqueous base solution.

10. A method of patterning a substrate comprising:

forming a layer of radiation-sensitive material on a substrate;

exposing said layer of radiation-sensitive material to a pattern of radiation, wherein said pattern includes;

a first region having a high radiation exposure,

a second region having a low radiation exposure, and

a third region having an exposure gradient ranging from about said high radiation exposure to about said low radiation exposure;

performing a post-exposure bake following said exposing;

performing negative-tone developing of said layer of radiation-sensitive material to remove said second region from said substrate to provide a developed layer of radiation-sensitive material;

removing said exposure gradient of said third region by transforming said third region, and optionally said first region, to a fourth region formed from said first and said third regions having a substantially uniform level of radiation exposure, polarity, or de-protection, or a combination thereof; and

slimming said fourth region.

11. The method of claim 10, wherein said layer of radiation-sensitive material comprises:

a material that decreases in polarity upon performing

said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material,

an acid wash and a post-acid wash bake of said layer of radiation-sensitive material,

a heating of said layer of radiation-sensitive material to a temperature equal to or greater than a thermal decomposition temperature of said radiation-sensitive material, or

any combination of two or more thereof;

or

an acid generator that generates acid upon performing

said exposing and said post-exposure bake following said exposing of said layer of radiation-sensitive material;

said acid wash and said post-acid wash bake of said layer of radiation-sensitive material;

said heating of said layer of radiation-sensitive material to said temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material, or

any combination of two or more thereof;

or

a protected polymer that undergoes de-protection upon heating to a temperature equal to or greater than a thermal decomposition temperature of said protected polymer.

12. The method of claim 11, wherein said change in polarity of said material is an increase in polarity, and wherein performing said negative-tone developing comprises contacting said layer of radiation-sensitive material with a first organic solvent-based composition to remove said second region from said substrate.

13. The method of claim 12, wherein said removing said exposure gradient comprises:

performing a flood exposure and a post-flood exposure bake of said developed layer of radiation-sensitive material;

performing an acid wash and a post-acid wash bake of said developed layer of radiation-sensitive material;

or

heating said developed layer of radiation-sensitive material to a temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material.

14. The method of claim 13, wherein said slimming said fourth region comprises:

contacting said fourth region with a second organic solvent-based composition.

15. The method of claim 13, wherein said slimming said fourth region comprises:

contacting said fourth region with an aqueous base solution to remove a portion of said fourth region, wherein said aqueous base solution is a dilute solution having a hydroxide salt concentration less than 0.02N.

16. The method of claim 13, wherein said slimming said fourth region comprises:

contacting said fourth region with an aqueous base solution to remove a portion of said fourth region, wherein said layer of radiation-sensitive material further comprises a muting agent.

17. The method of claim 13, wherein said slimming said fourth region comprises:

contacting said fourth region with an aqueous base solution at an ultra-cold temperature to remove a portion of said fourth region, wherein said ultra-cold temperature is less than 25°

C. and greater than a freezing point of said aqueous base solution.

18. The method of claim 11, wherein said change in polarity of said material is a decrease in polarity, and wherein performing said negative-tone developing comprises contacting said layer of radiation-sensitive material with a first aqueous base solution to remove said second region from said substrate.

19. The method of claim 18, wherein said removing said exposure gradient comprises:

performing a flood exposure and a post-flood exposure bake of said developed layer of radiation-sensitive material;

performing an acid wash and a post-acid wash bake of said developed layer of radiation-sensitive material;

or

heating said developed layer of radiation-sensitive material to a temperature equal to or greater than said thermal decomposition temperature of said radiation-sensitive material.

20. The method of claim 19, wherein said slimming said fourth region comprises

contacting said fourth region with an organic solvent-based composition at an ultra-cold temperature to remove a portion of said fourth region, wherein said ultra-cold temperature is less than 25°

C. and greater than a freezing point of said organic solvent-based composition.

21. The method of claim 19, wherein said slimming said fourth region comprises contacting said fourth region with an organic solvent-based composition to remove a portion of said fourth region, wherein said organic solvent-based composition achieves a rate of a dissolution ranging from about 0.1 nm/sec to about 5 nm/sec.

22. The method of claim 19, wherein said slimming said fourth region comprises contacting said fourth region with a second aqueous base solution to remove a portion of said fourth region.

23. The method of claim 19, wherein said slimming said fourth region comprises contacting said fourth region with a second aqueous solution comprising a promoting agent to remove a portion of said fourth region.

24. The method of claim 23, wherein the promoting agent is a salt comprising an alkali metal.

25. The method of claim 19, wherein said slimming said fourth region comprises contacting said fourth region with a second aqueous basic solution at a temperature ranging from about 30°

C. to about the boiling point of the aqueous base solution.