Use of topography to direct assembly of block copolymers in grapho-epitaxial applications

Patent metadata

Field	Value
Publication number	US-9418860-B2
Application number	US-201414518699-A
Country	US
Kind code	B2
Filing date	Oct 20, 2014
Priority date	Oct 20, 2013
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A method is provided for forming a patterned topography on a substrate. The substrate is provided with features formed atop that constitute an existing topography, and a template for directed self-assembly (DSA) is formed surrounding the exposed topography. Further to the method, the exposed template surfaces are chemically treated. In one embodiment, the surfaces are treated with a hydrogen-containing reducing chemistry to alter the surfaces to a less oxidized state. In another embodiment, the surfaces are coated with a first phase of a block copolymer (BCP) to render the surfaces more attractive to the first phase than prior to the coating. The template is then filled with the BCP to cover the exposed topography, and then the BCP is annealed within the template to drive self-assembly in alignment with the topography. Developing the annealed BCP exposes a DSA pattern immediately overlying the topography.

First claim

What is claimed is:

1. A method for forming a patterned topography on a substrate, comprising:
providing a substrate with features formed atop, the features forming an existing topography;
forming a template for directed self-assembly (DSA) immediately atop the topography, the template comprising exposed template surfaces surrounding regions of exposed topography;
treating the exposed template surfaces to alter at least one surface property thereof;
filling the template with a block copolymer (BCP) to cover the exposed topography;
annealing the block copolymer (BCP) within the template to drive self-assembly in alignment with the topography; and
developing the annealed block copolymer (BCP) to expose a directed self-assembly (DSA) pattern above the topography.

2. The method of claim 1 , wherein the step of forming the template comprises a plasma etching step using a first plasma comprising oxygen.

3. The method of claim 2 , wherein the step of treating the exposed template surfaces comprises exposing the template to a second plasma different than the first plasma.

4. The method of claim 3 , wherein the second plasma comprises hydrogen.

5. The method of claim 1 , wherein the step of treating the exposed template surfaces renders the exposed template surfaces less attractive to one phase of the block copolymer (BCP) compared to the exposed template surfaces prior to the treatment.

6. The method of claim 1 , wherein the step of treating the exposed template surfaces comprises exposing the template to a wet processing chemistry.

7. The method of claim 6 , wherein the wet processing chemistry comprises dilute hydrogen fluoride.

8. The method of claim 1 , wherein the block copolymer (BCP) comprises polystyrene (PS) and poly methyl methacrylate (PMMA).

9. The method of claim 1 , further comprising:
transferring the directed self-assembly (DSA) pattern into the topography, to form a patterned topography.

10. A method for forming a patterned topography on a substrate, comprising:
providing a substrate with features formed atop, the features forming an existing topography;
forming a template for directed self-assembly (DSA) immediately atop the topography, the template comprising exposed template surfaces surrounding regions of exposed topography, wherein forming the template comprises plasma etching with an oxygen-containing plasma whereby the exposed template surfaces are oxidized;
treating the exposed template surfaces with a hydrogen-containing reducing chemistry to alter the exposed template surfaces to a less oxidized state;
filling the template with a block copolymer (BCP) to cover the exposed topography;
annealing the block copolymer (BCP) within the template to drive self-assembly in alignment with the topography;
developing the annealed block copolymer (BCP) to expose a directed self-assembly (DSA) pattern above the topography; and
transferring the directed self-assembly (DSA) pattern into the topography, to form a patterned topography.

11. The method of claim 10 , wherein the block copolymer (BCP) comprises polystyrene (PS) and poly methyl methacrylate (PMMA), wherein the poly methyl methacrylate (PMMA) is attracted to oxidized surfaces such that the poly methyl methacrylate (PMMA) is less attracted to the treated exposed template surfaces having the less oxidized state than to the untreated exposed template surfaces.

12. A method for forming a patterned topography on a substrate, comprising:
providing a substrate with features formed atop, the features forming an existing topography;
forming a template for directed self-assembly (DSA) immediately atop the topography, the template comprising exposed template surfaces surrounding regions of exposed topography;
coating the exposed template surfaces with a first phase of a block copolymer (BCP) to render the exposed template surfaces more attractive to the first phase of the block copolymer (BCP) than prior to the coating;
filling the template with the block copolymer (BCP) to cover the topography;
annealing the block copolymer (BCP) within the template to drive self-assembly of the block copolymer (BCP) with a second phase of the block copolymer (BCP) in alignment with the topography; and
developing the annealed block copolymer (BCP) to expose a directed self-assembly (DSA) pattern immediately above the topography.

13. The method of claim 12 , further comprising:
performing a direct current superposition (DCS) treatment of the exposed template surfaces prior to coating the exposed template surfaces with the first phase of the block copolymer (BCP).

14. The method of claim 12 , further comprising:
exposing the exposed template surfaces to an oxygen-containing environment prior to coating the exposed template surfaces with the first phase of the block copolymer (BCP).

15. The method of claim 14 , wherein the oxygen-containing environment is an oxygen-containing plasma or ozone.

16. The method of claim 12 , further comprising:
exposing the exposed template surfaces to a wet processing chemistry comprising tetramethyl ammonium hydroxide (TMAH) prior to coating the exposed template surfaces with the first phase of the block copolymer (BCP).

17. The method of claim 12 , wherein the first phase of the block copolymer (BCP) is polystyrene (PS) and the second phase is poly methyl methacrylate (PMMA).

18. The method of claim 12 , further comprising:
transferring the directed self-assembly (DSA) pattern into the topography, to form a patterned topography.

19. A method for forming a patterned topography on a substrate, comprising:
providing a substrate with features formed atop, the features forming an existing topography;
forming a template for directed self-assembly (DSA) immediately atop the topography, the template comprising exposed template surfaces surrounding regions of exposed topography;
performing a direct current superposition (DCS) treatment of the exposed template surfaces to apply a layer of silicon to the exposed template surfaces;
exposing the layer of silicon on the exposed template surfaces to an oxygen-containing environment to oxidize the exposed template surfaces;
coating the oxidized exposed template surfaces with a brush polymer of OH and a first phase of a block copolymer (BCP) to render the exposed template surfaces more attractive to the first phase of the block copolymer (BCP) than prior to the coating;
filling the template with a block copolymer (BCP) to cover the exposed topography;
annealing the block copolymer (BCP) within the template to drive self-assembly of the block copolymer (BCP) with a second phase of the block copolymer (BCP) in alignment with the topography;
developing the annealed block copolymer (BCP) to expose a directed self-assembly (DSA) pattern immediately above the topography; and
transferring the directed self-assembly (DSA) pattern into the topography, to form a patterned topography.

20. The method of claim 19 , wherein the first phase of the block copolymer (BCP) is polystyrene (PS) and the second phase is poly methyl methacrylate (PMMA).

Assignees

• Tokyo Electron Ltd

Inventors

• Somervell Mark H
• Muramatsu Makoto
• Rathsack Benjamen M
• Tomita Tadatoshi
• Genjima Hisashi
• Yaegashi Hidetami
• Oyama Kenichi

Classifications

• H10P76/4088

  Processes for improving the resolution of the masks · CPC title

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title

• H10P76/4083

  characterised by their behaviours during the lithography processes, e.g. soluble masks or redeposited masks · CPC title

• H10P76/204

  of organic photoresist masks · CPC title

• H10P50/696

  Process specially adapted to improve the resolution of the mask · CPC title