Extreme Ultraviolet Photoresist and Method

• US 20200133124A1
• Filed: 12/23/2019
• Published: 04/30/2020
• Est. Priority Date: 05/30/2017
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Liu, Chen-Yu, Chang, Ya-Ching, Wu, Cheng-Han, Chang, Ching-Yu, Lin, Chin-Hsiang
• Granted Patent: US 11,378,884 B2
• Time in Patent Office: Days
• CPC Class Codes: G03F 7/0392 the macromolecular compound being present in a chemically amplified positive photoresist composition
• CPC Class Codes: G03F 7/0395 the macromolecular compound having a backbone with alicyclic moieties
• CPC Class Codes: G03F 7/0397 the macromolecular compound having an alicyclic moiety in a side chain
• CPC Class Codes: G03F 7/203 comprising an imagewise exposure to electromagnetic radiation or corpuscular radiation
• CPC Class Codes: G03F 7/30 Imagewise removal using liquid means
• CPC Class Codes: G03F 7/325 Non-aqueous compositions
• CPC Class Codes: G03F 7/38 Treatment before imagewise removal, e.g. prebaking G03F7/265 takes precedence

Abstract

The present disclosure provides a method for lithography patterning in accordance with some embodiments. The method includes forming a photoresist layer over a substrate. The photoresist layer includes at least an acid labile group (ALG) and a thermo-base generator (TBG). The method further includes exposing a portion of the photoresist layer to a radiation and performing a baking process after the exposing of the portion of the photoresist layer. The TBG releases a base during the performing of the baking process, resulting in a chemical reaction between the ALG and the base. The method further includes removing an unexposed portion of the photoresist layer, resulting in a patterned photoresist layer.

Claims

1. A method, comprising:

forming a photoresist layer over a substrate, wherein the photoresist layer includes at least an acid labile group (ALG) and a thermo-base generator (TBG);

exposing a portion of the photoresist layer to a radiation;

performing a baking process after the exposing of the portion of the photoresist layer, wherein the TBG releases a base during the performing of the baking process, resulting in a chemical reaction between the ALG and the base; and

removing an unexposed portion of the photoresist layer, resulting in a patterned photoresist layer.

2. The method of claim 1, wherein a polarity of the photoresist layer is adjusted after the chemical reaction between the ALG and the base.

3. The method of claim 2, wherein the adjusted polarity reduces a solubility of the photoresist layer in a negative tone developer.

4. The method of claim 1, wherein the photoresist layer further includes a polymer backbone, wherein the ALG is bonded to the polymer backbone.

5. The method of claim 4, wherein the photoresist layer further includes a sensitizer bonded to the polymer backbone.

6. The method of claim 1, wherein the ALG includes a t-butoxycardbonyl (tBOC) structure.

7. The method of claim 1, wherein the TBG includes a chemical structure selected from the group consisting of an amide, a sulfonamide, an imide, an imine, an O-acyl oxime, and a benzoyloxycarbonyl derivative.

8. The method of claim 1, wherein a weight percentage of the TBG in the photoresist layer is no more than 30%.

9. The method of claim 1, wherein the radiation is an extreme ultraviolet (EUV) radiation.

10. The method of claim 1, wherein the performing of the baking process includes baking the photoresist layer at a first temperature and subsequently at a second temperature, wherein the first temperature is lower than a triggering temperature for the TBG to release the base and the second temperature is higher than the triggering temperature.

11. A method for lithography patterning, comprising:

forming a photoresist layer over a substrate, wherein the photoresist layer includes a photoacid generator (PAG), an acid labile group (ALG), and a thermo-base generator (TBG);

exposing a portion of the photoresist layer to an extreme ultraviolet (EUV) radiation;

baking the photoresist layer at a first temperature to facilitate a reaction between the ALG and an acid released by the PAG, thereby forming a cleaved ALG, wherein the first temperature is lower than a triggering temperature for the TBG to release a base;

baking the photoresist layer at a second temperature higher than the triggering temperature, wherein the TBG releases the base, thereby causing a chemical reaction between the cleaved ALG and the base; and

developing the photoresist layer in a developer, thereby forming a patterned photoresist layer.

12. The method of claim 11, wherein the developing of the photoresist layer includes removing an unexposed portion of the photoresist layer in a negative tone developer.

13. The method of claim 11, wherein the first temperature is within a range of 90 degree Celsius to 130 degree Celsius and the second temperature is within a range of 140 degree Celsius to 250 degree Celsius.

14. The method of claim 11, wherein the chemical reaction includes converting a carboxyl group in the cleaved ALG to a carboxylate anion group.

15. The method of claim 14, wherein the carboxyl group is a —

COOH bonded to a polymer backbone, and wherein a solubility of the photoresist layer in the developer is reduced after the chemical reaction with the base.

16. A method for lithography patterning, comprising:

forming a photoresist layer over a substrate, wherein the photoresist layer includes a polymer backbone, an acid labile group (ALG) bonded to the polymer backbone, a photo-acid generator (PAG), and a photobase generator (PBG);

performing a first exposing process to the photoresist layer, wherein the PBG is insensitive to the first exposing process;

baking the photoresist layer, resulting in a cleaved ALG;

performing a second exposing process to the photoresist layer, wherein the PBG is sensitive to the second exposing process and releases a base that reacts with the cleaved ALG; and

developing the photoresist layer in a developer, thereby forming a patterned resist layer.

17. The method of claim 16, wherein the first and second exposing processes use radiations of different wavelengths.

18. The method of claim 16, wherein the first and second exposing processes use radiations of a same wavelength but with different doses.

19. The method of claim 16, wherein the second exposing process is a blanket exposing applied to the whole photoresist layer.

20. The method of claim 16, wherein the PBG includes a chemical structure selected from the group consisting of carbamate, carbamonylhydroxy amine, oxime, sulfonamide, lactam, and cyclic amide.