Method for directed self-assembly (DSA) of block copolymers using guiding line sidewalls

Patent metadata

Field	Value
Publication number	US-9458531-B2
Application number	US-201414532240-A
Country	US
Kind code	B2
Filing date	Nov 4, 2014
Priority date	Nov 4, 2014
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

A guiding pattern for directed self-assembly (DSA) of a block copolymer (BCP) is an array of spaced guiding stripes on a substrate that have a width equal to nL 0 and a pitch equal to (n+k)L 0 , where n and k are integers equal to or greater than 1 and L 0 is the natural pitch of the BCP. The guiding stripes have oxidized sidewalls. A silicon-containing BCP self-assembles with the BCP component without silicon wetting the oxidized sidewalls. Then oxygen reactive ion etching (RIE) removes the BCP component without silicon and oxidizes the silicon-containing BCP component. The remaining pattern of silicon oxide containing BCP component can then be used as an etch mask to etch the underlying substrate.

First claim

What is claimed is:

1. A method of directed self-assembly (DSA) of a block copolymer (BCP) having a natural pitch L 0 comprising:
providing a substrate;
forming on the substrate a cross-linked polymer mat layer;
patterning on the mat layer a resist layer into a plurality of spaced resist stripes having a width substantially equal to nL 0 and a pitch substantially equal to (n+k)L 0 , where n and k are integers equal to or greater than 1;
reactive ion etching the exposed mat layer in an oxygen gas to remove the mat layer between the resist stripes and simultaneously oxidize the sidewalls of stripes of mat layer beneath the resist stripes, leaving a plurality of mat guiding stripes with oxidized sidewalls, the guiding stripes having a width substantially equal to nL 0 and a pitch substantially equal to (n+k)L 0 , where n and k are integers equal to or greater than 1;
removing the resist;
depositing onto the substrate between the guiding stripes a layer of polymer brush material;
heating the polymer brush material to bind it to the substrate;
removing unbound polymer brush material, leaving bound polymer brush material between the guiding stripes and having a thickness less than the thickness of the guiding stripes, thereby exposing the oxidized sidewalls of the guiding stripes;
depositing a BCP comprising first and second BCP components on the guiding stripes and bound brush material; and
heating said deposited BCP to cause one of the components to wet the oxidized sidewalls and the BCP to self-assemble into said first and second components on the guiding stripes and bound brush material.

2. The method of claim 1 wherein the polymer mat layer is cross-linked polystyrene.

3. The method of claim 1 wherein the polymer brush material is OH-terminated polystyrene.

4. The method of claim 1 wherein the substrate is formed of a material selected from single-crystal Si, amorphous Si, silica, fused quartz, silicon nitride, carbon, tantalum, molybdenum, chromium, alumina and sapphire.

5. The method of claim 1 wherein the substrate comprises a base selected from single-crystal Si, amorphous Si and fused quartz, and a hard mask layer formed on said base.

6. The method of claim 1 further comprising depositing a hard mask layer is comprising diamond-like carbon (DLC) on the substrate prior to forming the polymer mat layer.

7. The method of claim 1 wherein the BCP has a natural pitch L 0 less than 20 nm.

8. The method of claim 1 wherein the BCP is a silicon-containing BCP.

9. The method of claim 8 wherein the BCP is selected from poly(trimethylsilyl styrene)-block-poly(methoxystyrene) (PTMSS-b-PMOST), poly(styrene-block-dimethylsiloxane) (PS-b-PDMS), poly(trimethylsilylstyrene-block-D,L lactide) (PTMSS-b-PLA), and poly(styrene-block-trimethylsilylstyrene-block-styrene) (PS-b-PTMSS-b-PS).

10. The method of claim 1 further comprising, prior to heating the depositing BCP, spin-coating a polarity-switching topcoat on the deposited BCP.

11. The method of claim 1 wherein the difference in thickness between the mat guiding stripes and the bound brush material is greater than or equal to 2 nm and less than or equal to 10 nm.

12. The method of claim 1 wherein patterning the resist layer into a plurality of spaced resist stripes comprises patterning the stripes into a pattern selected from parallel stripes, concentric rings and generally radial lines.

13. A method for etching a substrate comprising:
the method of claim 1 ;
after the BCP has self-assembled, removing one of said first and second BCP components;
etching the substrate, using the other of said first and second BCP components as an etch mask; and
thereafter removing said other BCP component, leaving the etched substrate.

14. A method for etching a substrate using directed self-assembly (DSA) of a block copolymer (BCP) having a natural pitch L 0 comprising:
providing a substrate comprising a base selected from single-crystal Si, amorphous Si and fused quartz, and a hard mask layer formed on said base;
forming on the hard mask layer a cross-linked polymer mat layer;
patterning on the mat layer a resist layer into a plurality of spaced resist stripes having a width substantially equal to nL 0 and a pitch substantially equal to (n+k)L 0 , where n and k are integers equal to or greater than 1;
reactive ion etching the exposed mat layer in an oxygen gas to remove the mat layer between the resist stripes, leaving a plurality of mat guiding stripes with oxidized sidewalls, the guiding stripes having a width substantially equal to nL 0 and a pitch substantially equal to (n+k)L 0 , where n and k are integers equal to or greater than 1;
removing the resist;
depositing onto the substrate between the guiding stripes a layer of polymer brush material;
heating the polymer brush material to bind it to the substrate;
removing unbound polymer brush material, leaving bound polymer brush material between the guiding stripes and having a thickness less than the thickness of the guiding stripes, thereby exposing the oxidized sidewalls of the guiding stripes;
spin-coating a BCP comprising a first silicon-containing component and a second BCP component on the guiding stripes and bound brush material;
spin-coating a polarity-switching topcoat on the BCP;
heating said deposited BCP to cause the second BCP component to wet the oxidized sidewalls and the BCP to thereby self-assemble into said first and second components on the guiding stripes and bound brush material;
after the BCP has self-assembled, removing the second BCP component;
etching the hard mask layer, using the first silicon-containing BCP component as an etch mask; and
etching the substrate base, using the etched hard mask layer as a mask, leaving the etched substrate base.

15. The method of claim 14 wherein the polymer mat layer is cross-linked polystyrene.

16. The method of claim 14 wherein the BCP has a natural pitch L 0 less than 20 nm.

17. The method of claim 14 wherein the difference in thickness between the mat guiding stripes and the bound brush material is greater than or equal to 2 nm and less than or equal to 10 nm.

18. The method of claim 14 wherein the hard mask layer comprises diamond-like carbon (DLC).

19. The method of claim 14 wherein the BCP is selected from poly(trimethylsilyl styrene)-block-poly(methoxystyrene) (PTMSS-b-PMOST), poly(styrene-block-dimethylsiloxane) (PS-b-PDMS), poly(trimethylsilylstyrene-block-D,L lactide) (PTMSS-b-PLA), and poly(styrene-block-trimethylsilylstyrene-block-styrene) (PS-b-PTMSS-b-PS).

20. The method of claim 14 wherein patterning the resist layer into a plurality of spaced resist stripes comprises patterning the stripes into a pattern selected from parallel stripes, concentric rings and generally radial lines.

Assignees

• HGST Netherlands BV

Inventors

• Cushen Julia
• Ruiz Ricardo
• Wan Lei

Classifications

• C23C14/042 Primary

  using masks · CPC title

• G03F7/0002 Primary

  Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping · CPC title