Composition and method for lithography patterning

• US 10,082,734 B2
• Filed: 02/13/2015
• Issued: 09/25/2018
• Est. Priority Date: 02/13/2015
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Su, Yu-Chung, Chang, Ching-Yu
• Primary Examiner(s): Lee, Sin J
• Application Number:
  US14/621,512
• Publication Number:
  US 20160238933A1
• Time in Patent Office: 1,320 Days
• Field of Search: None
• CPC Class Codes: C09D 5/006 Anti-reflective coatings
• CPC Class Codes: G03F 7/038 Macromolecular compounds which are rendered insoluble or differentially wettable G03F7/075 takes precedence; macromolecular azides G03F7/012; macromolecular diazonium compounds G03F7/021
• CPC Class Codes: G03F 7/0382 the macromolecular compound being present in a chemically amplified negative photoresist composition
• CPC Class Codes: G03F 7/0392 the macromolecular compound being present in a chemically amplified positive photoresist composition
• CPC Class Codes: G03F 7/091 characterised by antireflection means or light filtering or absorbing means, e.g. anti-halation, contrast enhancement
• CPC Class Codes: G03F 7/322 Aqueous alkaline compositions
• CPC Class Codes: G03F 7/325 Non-aqueous compositions
• CPC Class Codes: G03F 7/36 Imagewise removal not covered by groups G03F7/30 - G03F7/34, e.g. using gas streams, using plasma
• CPC Class Codes: H01L 21/0276 using an anti-reflective coating anti-reflective coating for lithography in general G03F7/09
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials

Abstract

An anti-reflective coating (ARC) composition for use in lithography patterning and a method of using the same is disclosed. In an embodiment, the ARC composition comprises a polymer having a chromophore; an acid labile group (ALG), more than 5% by weight; a thermal acid generator; and an optional crosslinker. The method includes applying the ARC composition over a substrate; crosslinking the polymer to form an ARC layer; cleaving the ALG of the ARC layer to reduce a film density of the ARC layer; forming a resist layer over the ARC layer, patterning the resist layer, and etching the ARC layer. Due to reduced film density, the ARC layer has a high etching rate, thereby preserving the critical dimension (CD) of the resist pattern during the etching process.

Claims

1. A method for lithography patterning, comprising:

receiving a substrate;

applying an anti-reflective coating (ARC) composition over the substrate;

forming an ARC layer by radiating the ARC composition with an ultraviolet (UV) radiation to crosslink the ARC composition;

reducing a film density of the ARC layer by cleaving an acid labile group (ALG) in the ARC layer; and

after the reducing the film density of the ARC layer, forming a resist layer over the ARC layer.

2. The method of claim 1, wherein the cleaving of the ALG includes baking the ARC layer at a first temperature so as to thermally generate an acid in the ARC layer.

3. The method of claim 1, wherein the applying of the ARC composition includes a spin coating process.

4. The method of claim 1, further comprising:

patterning the resist layer, resulting in a patterned resist layer; and

etching the ARC layer using the patterned resist layer as an etch mask.

5. The method of claim 4, wherein the etching of the ARC layer is by dry etching.

6. The method of claim 4, wherein the patterning of the resist layer includes:

exposing the resist layer; and

developing the resist layer in a developer that does not substantially dissolve the ARC layer.

7. The method of claim 1, wherein the substrate includes silicon.

8. The method of claim 1, wherein prior to the reducing the film density of the ARC layer, the ARC layer has a first etching rate associated with an etching chemical, and

wherein after the reducing the film density of the ARC layer, the ARC layer has a second etching rate associated with the etching chemical, wherein the second etching rate is higher than the first etching rate.

9. A method for lithography patterning, comprising:

receiving a substrate;

applying an anti-reflective coating (ARC) composition over the substrate wherein the ARC composition comprises a polymer, an acid labile group (ALG) connecting a chromophore to a polymer backbone of the polymer; and

a thermal acid generator;

forming an ARC layer by baking the ARC composition at a first temperature to crosslink the polymer;

reducing a film density of the ARC layer by baking the ARC layer at a second temperature higher than the first temperature, wherein the reducing the film density of the ARC layer includes;

removing the ALG and the chromophore connected to the ALG in the ARC layer; and

forming a resist layer over the ARC layer.

10. The method of claim 9, wherein the ARC composition further comprises a crosslinker.

11. The method of claim 9, wherein the baking the ARC layer at the second temperature causes the thermal acid generator to generate a first acid.

12. The method of claim 11, wherein the crosslinking of the polymer is in the presence of a second acid that is different from the first acid.

13. The method of claim 12, wherein the baking the ARC composition at the first temperature causes a second thermal acid generator of the ARC composition to generate the second acid.

14. The method of claim 11, wherein the reducing the film density of the ARC layer includes:

cleaving the ALG of the ARC layer using the first acid.

15. The method of claim 14, wherein after the reducing the film density, the ARC layer has a lower etching resistance.

16. The method of claim 9, further comprising:

patterning the resist layer, resulting in a patterned resist layer; and

applying a dry etching process to the ARC layer using the patterned resist layer as an etch mask, resulting in a patterned ARC layer underneath the patterned resist layer.

17. The method of claim 16, further comprising:

processing the substrate using the patterned resist layer and the patterned ARC layer as a mask.

18. An anti-reflective coating (ARC) composition for use in lithography patterning, comprising:

a polymer, about 35% to about 95% by weight, wherein the polymer includes a chromophore;

an acid labile group (ALG), more than 5% by weight,

wherein the ALG connects the chromophore to a polymer backbone of the polymer;

a first thermal acid generator for generating a first acid for crosslinking the polymer at a first temperature; and

a second thermal acid generator for generating a second acid for cleaving the ALG and removing the chromophore connected to the ALG at a second temperature higher than the first temperature, wherein the second acid is different from the first acid.

19. The ARC composition of claim 18, wherein the second thermal acid generator is more than 0.05% by weight.

20. The ARC composition of claim 18, further comprising:

a crosslinker, less than about 60% by weight.