Flood exposure process for dual tone development in lithographic applications

• US 20100273099A1
• Filed: 04/27/2009
• Published: 10/28/2010
• Est. Priority Date: 04/27/2009
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: FONSECA, Carlos A., SOMERVELL, Mark, SCHEER, Steven
• Granted Patent: US 8,568,964 B2
• Time in Patent Office: Days
• US Class Current: 430/30
• CPC Class Codes: G03F 7/095 having more than one photosensitive layer G03F7/075 takes precedence
• CPC Class Codes: G03F 7/30 Imagewise removal using liquid means
• CPC Class Codes: G03F 7/70466 Multiple exposures, e.g. combination of fine and coarse exposures, double patterning or multiple exposures for printing a single feature stitching G03F7/70475

Abstract

A method and system for patterning a substrate using a dual tone development process is described. The method and system comprise a flood exposure of the substrate to improve process latitude for the dual tone development process.

Claims

1. A method of patterning a substrate, comprising:

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

performing a patterned exposure of said layer of radiation-sensitive material;

performing a first post-exposure bake following said performing said patterned exposure;

performing positive-tone developing of said layer of radiation-sensitive material to remove first radiation-sensitive material portions from said substrate;

performing a flood exposure of said layer of radiation-sensitive material;

performing a second post-exposure bake following said performing said flood exposure; and

performing negative-tone developing of said layer of radiation-sensitive material to remove second radiation-sensitive material portions from said substrate.

2. The method of claim 1, wherein said performing said patterned exposure of said layer of radiation-sensitive material comprises exposing said layer of radiation-sensitive material to a pattern of radiation using a mask having a mask critical dimension to form said first radiation-sensitive material portions having a high radiation exposure, said second radiation-sensitive material portions having a low radiation exposure, and third radiation-sensitive material portions having an intermediate radiation exposure.

3. The method of claim 2, further comprising:

adjusting a critical dimension of said third radiation-sensitive material portions having said intermediate radiation exposure by altering said patterned exposure, said first post-exposure bake, said positive-tone developing, said flood exposure, or said second post-exposure bake, or any combination of two or more thereof.

4. The method of claim 3, wherein said adjusting comprises adjusting said mask critical dimension for said patterned exposure, an exposure dose for said patterned exposure, an exposure intensity for said patterned exposure, an exposure wavelength of said patterned exposure, a first post-exposure temperature for said first post-exposure bake, a time said substrate is elevated to said first post-exposure temperature, a heating rate for achieving said first post-exposure temperature, a cooling rate for reducing said first post-exposure temperature, a pressure of a gaseous environment surrounding said substrate during said elevation of said substrate to said first post-exposure temperature, a composition of a gaseous environment surrounding said substrate during said elevation of said substrate to said first post-exposure temperature, a second post-exposure temperature for said second post-exposure bake, a time said substrate is elevated to said second post-exposure temperature, a heating rate for achieving said second post-exposure temperature, a cooling rate for reducing said second post-exposure temperature, a pressure of a gaseous environment surrounding said substrate during said elevation of said substrate to said second post-exposure temperature, a composition of a gaseous environment surrounding said substrate during said elevation of said substrate to said second post-exposure temperature, a composition of a first developing chemistry for said positive-tone developing, a time duration for applying said first developing chemistry, a temperature of said first developing chemistry, a composition of a second developing chemistry for said negative-tone developing, a time duration for applying said second developing chemistry, a temperature of said second developing chemistry, an exposure dose for said flood exposure, an exposure intensity for said flood exposure, an exposure wavelength of said flood exposure, or a composition of the layer of radiation-sensitive material, or any combination of two or more thereof.

5. The method of claim 1, wherein said performing said flood exposure comprises exposing said substrate to electromagnetic (EM) radiation having a wavelength in the visible spectrum, or EM radiation having a wavelength in the ultraviolet spectrum, or a combination thereof.

6. The method of claim 1, wherein said performing said flood exposure comprises exposing said substrate to continuous EM radiation, pulsed EM radiation, poly-chromatic EM radiation, mono-chromatic EM radiation, broad-band EM radiation, or narrow-band radiation, or a combination thereof.

7. The method of claim 1, wherein said performing said flood exposure comprises exposing said substrate to 436 nm (nanometer) EM radiation, 365 nm EM radiation, 248 nm EM radiation, 193 nm EM radiation, 157 nm EM radiation, or deep ultraviolet (DUV) EM radiation, or any combination of two or more thereof.

8. The method of claim 1, wherein said layer of radiation-sensitive material comprises a positive-tone photo-resist, a dual tone photo-resist, or a photo-resist having one or more photo-acid generators.

9. The method of claim 8, wherein:

said layer of radiation-sensitive material comprises a first photo-acid generator and a second photo-acid generator;

said first photo-acid generator generates acid in said layer of radiation-sensitive material when exposed to EM radiation at a first wavelength or first range of wavelengths; and

said second photo-acid generator generates acid in said layer of radiation-sensitive material when exposed to EM radiation at a second wavelength or second range of wavelengths.

10. The method of claim 9, wherein said performing said patterned exposure is configured for exposing said layer of radiation-sensitive material to said first wavelength or first range of wavelengths, and said performing said flood exposure is configured for exposing said layer of radiation-sensitive material to said second wavelength or second range of wavelengths.

11. The method of claim 9, said performing said flood exposure is configured for exposing said layer of radiation-sensitive material to said first wavelength or first range of wavelengths and to said second wavelength or second range of wavelengths.

12. The method of claim 1, wherein said layer of radiation-sensitive material comprises a photo-resist that switches solubility due to a change in polarity upon said performing said patterned exposure, said performing said flood exposure, said performing said first post-exposure bake following said patterned exposure, or said performing said second post-exposure bake following said flood exposure, or any combination of two or more thereof, or wherein said layer of radiation-sensitive material comprises a photo-resist that provides acid-catalyzed deprotection upon said performing said patterned exposure, said performing said flood exposure, said performing said first post-exposure bake following said patterned exposure, or said performing said second post-exposure bake following said flood exposure, or any combination of two or more thereof.

13. A platform configured for patterning a substrate, comprising:

a track system configured to coat a substrate with a layer of radiation-sensitive material;

a lithography system including a pattern exposure system configured to expose said substrate to patterned EM radiation;

a flood exposure system configured to expose said substrate to un-patterned EM radiation; and

a transfer system configured to transfer said substrate between said track system, said pattern exposure system, and said flood exposure system.

14. The platform of claim 13, wherein said flood exposure system is integrated with said pattern exposure system within said lithography system.

15. The platform of claim 14, wherein said pattern exposure system comprises a radiation source, a mask imaging system, and a substrate holder.

16. The platform of claim 15, wherein said flood exposure system comprises said radiation source, a mask-less imaging system, and said substrate holder.

17. The platform of claim 16, wherein said flood exposure system is integrated within said track system.

18. The platform of claim 13, wherein said flood exposure system comprises a stand-alone module separate from said track system and said pattern exposure system, and coupled to said track system or said pattern exposure system or both.

19. The platform of claim 13, wherein said flood exposure system is configured to expose said substrate to continuous EM radiation, pulsed EM radiation, poly-chromatic EM radiation, mono-chromatic EM radiation, broad-band EM radiation, or narrow-band radiation, or a combination thereof.

20. The platform of claim 13, wherein said flood exposure system comprises one or more lamps, one or more LEDs, or one or more lasers, or a combination of two or more thereof.