PATTERN DECOMPOSITION FOR DIRECTED SELF ASSEMBLY PATTERNS TEMPLATED BY SIDEWALL IMAGE TRANSFER

• US 20170162380A1
• Filed: 01/03/2017
• Published: 06/08/2017
• Est. Priority Date: 12/03/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Guillorn, Michael A., Cheng, Joy, Tsai, Hsinyu, Liu, Chi-Chun
• Granted Patent: US 9,911,603 B2
• Time in Patent Office: Days
• CPC Class Codes: B81C 2201/0198 for making a masking layer
• CPC Class Codes: C08L 53/00 Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 53/005 Modified block copolymers
• CPC Class Codes: G03F 1/00 Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: H01L 21/0271 comprising organic layers
• CPC Class Codes: H01L 21/0274 Photolithographic processes
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/308 using masks H01L21/3063, H01L21/3065 take precedence
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/3086 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 21/76816 Aspects relating to the layout of the pattern or to the size of vias or trenches layout of the interconnections per se H01L23/528; CAD of ICs G06F30/00

Abstract

After forming spacers over a hard mask layer using a sidewall image transfer process, a neutral material layer is formed on the portions of the hard mask layer that are not covered by the spacers. The spacers and the neutral material layer guide the self-assembly of a block copolymer material. The microphase separation of the block copolymer material provides a lamella structure of alternating domains of the block copolymer material.

Claims

1. A method of directed self-assembly of a block copolymer material comprising:

forming spacers on sidewalls of a plurality of mandrels located on a template layer that is present over a hard mask layer;

removing the plurality of mandrels, leaving the spacers protruding from a top surface of the template layer;

removing portions of the template layer that are not cover by the spacers to provide template structures; and

forming a neutral material layer on exposed portions of the hard mask layer that are not covered by the template structures, wherein the neutral material layer only surrounds a bottom portion of each of the template structures and directly contacts opposite sidewalls of each of the template structures.

2. The method of claim 1, wherein the neutral material layer comprises a material that is chemically neutral to polymer blocks in the block copolymer material.

3. The method of claim 2, wherein the neutral material layer is made from a polymer brush material end substituted with a reactive functional group that is capable of bound to the top surface of the hard mask layer.

4. The method of claim 3, wherein the block copolymer material comprises polystyrene (PS) and poly(methyl methacrylate) (PMMA) (PS-b-PMMA), and the random copolymer comprises PS and PMMA having an OH end group (PS-r-PMMA-OH).

5. The method of claim 2, wherein the neutral material layer comprises a nitrogen-doped silicon carbide, a nitrogen-doped hydrogenated silicon carbide, or combinations thereof.

6. The method of claim 3, wherein the forming the neutral material layer comprises:

depositing the polymer brush material over exposed surfaces of the hard mask layer and the template structures;

baking the polymer brush material to cause the polymer brush material to bound to the top surface of the hard mask layer; and

removing an unreacted portion of the polymer brush material.

7. The method of claim 1, wherein the template layer comprises hydrogen silsesquioxane (HSQ) or methyl silsesquioxane (MSQ).

8. The method of claim 1, further comprising:

depositing the block copolymer material onto the neutral material layer and between the template structures;

annealing the block copolymer material to cause the directed self-assembly of the block copolymer material into alternating first domains including a first polymer block of the block copolymer material and second domains including a second polymer block of the block copolymer material; and

removing the second domains selective to the first domains.

9. The method of claim 8, wherein after the removing the second domains, the first domains protrude from a top surface of the neutral material layer, and the neutral material layer remains contacting the opposite sidewalls of each of the template structures.

10. The method of claim 8, wherein a first subset of the second domains is in direct contact with the opposite sidewalls of the template structures and a second subset of the second domains is distal from, and does not contact, the template structures.

11. The method of claim 10, wherein the removing the second domains removes the second subset of the second domains, but not the first subset of the second domains.

12. The method of claim 10, wherein the first subset of the second domains has a width equal to one half of a width of the second subset of the second domains.

13. The method of claim 1, wherein the forming the spacers comprises:

forming a spacer material layer on exposed surfaces of the plurality of mandrels and the template layer; and

removing horizontal portions of the spacer material layer, leaving vertical portions of the spacer material layer on the sidewalls of the plurality of mandrels.

14. The method of claim 1, further comprising removing the spacers from top surfaces of the template structures prior to the forming the neutral material layer.

15. The method of claim 14, wherein the removing the spacers is performed by an anisotropic etch or an isotropic etch.

16. The method of claim 14, wherein the removing the spacers is performed by chemical mechanical planarization.

17. The method of claim 1, further comprising forming the plurality of mandrels, wherein the forming the plurality of mandrels comprises:

forming a mandrel material layer on a top surface of the hard mask layer; and

patterning the mandrel material layer to provide the plurality of mandrels.

18. The method of claim 1, wherein the removing the plurality of mandrels is performed by an oxygen-based plasma etching.

19. The method of claim 1, wherein the hard mask layer comprises a dielectric oxide or a dielectric metal oxide.

20. The method of claim 1, wherein the hard mask layer comprises a nitrogen-doped silicon carbide, a nitrogen-doped hydrogenated silicon carbide, or a combination thereof.