Critical dimension control in photo-sensitized chemically-amplified resist

Patent metadata

Field	Value
Publication number	US-9645495-B2
Application number	US-201514816587-A
Country	US
Kind code	B2
Filing date	Aug 3, 2015
Priority date	Aug 13, 2014
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

Resist compositions for photosensitive chemically amplified resist processing, as well as methods for processing substrates using a photosensitive chemically amplified resist are disclosed for improved CD uniformity. A resist composition or layer generates photosensitizer when the resist is exposed to a first wavelength of light. A second wavelength of light is later used to amplify an acid reaction. The radiation-sensitive layer also includes a photo-active agent that, when exposed to a third light wavelength, modifies a concentration of photosensitizer in the radiation-sensitive layer. The third light wavelength can be projected as a pattern of radiation using a digital pixel-based projection system, with the projected pattern based on a critical dimension signature. In a subsequent exposure step, the resist layer is exposed to light of the second wavelength that induces or amplifies the acid concentration within the photoresist film.

First claim

The invention claimed is:

1. A method for patterning a substrate, the method comprising:
receiving a substrate having a radiation-sensitive layer deposited on an underlying layer, the radiation-sensitive layer comprising (1) a photosensitizer generation compound that, when exposed to a first light wavelength, generates photosensitizer molecules in the radiation-sensitive layer,(2) a photo acid generator compound that, when exposed to a second light wavelength, generates photo acid, and (3) a photo-active agent that, when exposed to a third light wavelength, modifies a concentration of photosensitizer in the radiation-sensitive layer;
executing a lithographic exposure adjustment process that projects a pattern of radiation of the third light wavelength onto the radiation-sensitive layer using a digital pixel-based projection system having an array of independently addressable projection points, the projected pattern being based on a critical dimension signature that spatially characterizes critical dimension values of structures corresponding to the substrate, the lithographic exposure adjustment process modifying photosensitizer concentration based on the projected pattern;
executing a lithographic exposure process that exposes the radiation-sensitive layer to radiation of the first light wavelength through a patterned mask such that photosensitizer molecules are generated in exposed portions of the radiation-sensitive layer; and
executing an exposure gain amplification process that flood exposes the radiation-sensitive layer with radiation of the second light wavelength causing photo acid generation in the radiation-sensitive layer at locations of photosensitizer molecules.

2. The method of claim 1 , wherein the photoactive agent is a second photo acid generator compound.

3. The method of claim 1 , wherein the lithographic exposure adjustment process is executed prior to executing the lithographic exposure process, and the lithographic exposure process is executed prior to executing the exposure gain amplification process.

4. The method of claim 1 , wherein the lithographic exposure adjustment process is executed subsequent to executing the lithographic exposure process, and the lithographic exposure process is executed prior to executing the exposure gain amplification process.

5. The method of claim 1 , wherein first light wavelength is selected from an EUV (extreme ultraviolet) light range.

6. The method of claim 1 , wherein the lithographic exposure adjustment projects the third light wavelength at less than seven millijoules per centimeter squared.

7. The method of claim 6 , wherein the third light wavelength has a light wavelength selected from the group consisting of I-line, 248 nm, 193 nm, and white light.

8. The method of claim 1 , wherein the second light wavelength and the third light wavelength are the same.

9. The method of claim 1 , wherein the second light wavelength and the third light wavelength are different.

10. The method of claim 1 , wherein critical dimension signature characterizes observed critical dimension values from a previously-measured substrate.

11. The method of claim 1 , wherein the critical dimension signature is identified prior to executing the lithographic exposure adjustment process.

12. The method of claim 1 , wherein the critical dimension signature is based on exposure characteristics of a specific photolithography exposure system that uses a photomask.

13. The method of claim 1 , further comprising:
developing a latent pattern in the radiation-sensitive layer resulting in the radiation-sensitive layer defining a relief pattern; and
transferring the relief pattern into the underlying layer using the radiation-sensitive layer as an etch mask.

14. The method of claim 1 , further comprising:
developing a latent pattern in the radiation-sensitive layer after executing all of the lithographic exposure adjustment process, the lithographic exposure process, and the exposure gain amplification process.

15. A method for patterning a substrate, the method comprising:
receiving a substrate having a radiation-sensitive layer deposited on an underlying layer, the radiation-sensitive layer comprising (1) a photosensitizer generation compound that, when exposed to a first light wavelength, generates photosensitizer molecules in the radiation-sensitive layer,(2) a photo acid generator compound that, when exposed to a second light wavelength, generates photo acid, and (3) a photo-active agent that, when exposed to a third light wavelength, modifies a concentration of photosensitizer in the radiation-sensitive layer, wherein the photoactive agent is a photo-destructive base;
executing a lithographic exposure adjustment process that projects a pattern of radiation of the third light wavelength onto the radiation-sensitive layer using a digital pixel-based projection system having an array of independently addressable projection points, the projected pattern being based on a critical dimension signature that spatially characterizes critical dimension values of structures corresponding to the substrate, the lithographic exposure adjustment process modifying photosensitizer concentration based on the projected pattern;
executing a lithographic exposure process that exposes the radiation-sensitive layer to radiation of the first light wavelength through a patterned mask such that photosensitizer molecules are generated in exposed portions of the radiation-sensitive layer; and
executing an exposure gain amplification process that flood exposes the radiation-sensitive layer with radiation of the second light wavelength causing photo acid generation in the radiation-sensitive layer at locations of photosensitizer molecules.

16. A method for patterning a substrate, the method comprising:
receiving a substrate having a radiation-sensitive layer deposited on an underlying layer, the radiation-sensitive layer comprising (1) a photosensitizer generation compound that, when exposed to a first light wavelength, generates photosensitizer molecules in the radiation-sensitive layer,(2) a photo acid generator compound that, when exposed to a second light wavelength, generates photo acid, and (3) a photo-active agent that, when exposed to a third light wavelength, modifies a concentration of photosensitizer in the radiation-sensitive layer, wherein the photoactive agent is a thermal acid generator compound;
executing a lithographic exposure adjustment process that projects a pattern of radiation of the third light wavelength onto the radiation-sensitive layer using a digital pixel-based projection system having an array of independently addressable projection points, the projected pattern being based on a critical dimension signature that spatially characterizes critical dimension values of structures corresponding to the substrate, the lithographic exposure adjustment process modifying photosensitizer concentration based on the projected pattern;
executing a lithographic exposure process that exposes the radiation-sensitive layer to radiation of the first light wavelength through a patterned mask such that photosensitizer molecules are generated in exposed portions of the radiation-sensitive layer; and
executing an exposure gain amplification process that flood exposes the radiation-sensitive layer with radiation of the second light wavelength causing photo acid generation in the radiation-sensitive layer at locations of photosensitizer molecules.

Assignees

• Tokyo Electron Ltd

Inventors

• Devilliers Anton J

Classifications

• G03F7/2022 Primary

  Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure · CPC title

• G03F7/095

  having more than one photosensitive layer (G03F7/075 takes precedence) · CPC title

• G03F7/0045

  with organic non-macromolecular light-sensitive compounds not otherwise provided for, e.g. dissolution inhibitors · CPC title