Positive tone bi-layer imprint lithography method

• US 20040188381A1
• Filed: 03/25/2003
• Published: 09/30/2004
• Est. Priority Date: 03/25/2003
• Status: Active Grant

• Current Assignee: Mii Newco, Inc.
• Original Assignee: Molecular Imprints, Inc. (Canon Inc.)
• Inventors: Sreenivasan, Sidlgata V.
• Granted Patent: US 7,179,396 B2
• Time in Patent Office: Days
• US Class Current: 216/40
• CPC Class Codes: B81C 1/0046 using stamping, e.g. imprinting nanoimprinting for making etch masks G03F7/0002
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• 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 21/76802 by forming openings in dielectrics

Abstract

The present invention provides a method to pattern a substrate which features creating a multi-layered structure by forming, on the substrate, a patterned layer having protrusions and recessions. Formed upon the patterned layer is a conformal layer, with the multi-layered structure having a crown surface facing away from the substrate. Portions of the multi-layered structure are removed to expose regions of the substrate in superimposition with the protrusions, while forming a hard mask in areas of the crown surface in superimposition with the recessions.

Claims

1. A method of patterning a substrate, said method comprising:

creating a multi-layered structure by forming, on said substrate, a patterned layer having protrusions and recessions, and forming, upon said patterned layer, a conformal layer, with said multi-layered structure having a crown surface facing away from said substrate; and

selectively removing portions of said multi-layered structure to expose regions of said substrate in superimposition with said protrusions while forming a hard mask in areas of said crown surface in superimposition with said recessions.

2. The method as recited in claim 1 wherein forming said patterned layer further includes providing said protrusions with an apex and a height and forming said conformal layer further includes providing said conformal layer with a normalization surface spaced apart from one apex a minimum distance and spaced-apart from an additional apex a maximum distance with said height being greater than a difference between said maximum distance and said minimum distance.

3. The method as recited in claim 1 wherein creating further includes forming said patterned layer from an organic polymerizable material substantially free of silicon and forming said conformal layer from a silicon-containing polymerizable material.

4. The method as recited in claim 1 wherein creating further includes forming said patterned layer from a material having a polymerizable compound and a surfactant having a surface energy that is less than a surface energy of said polymerizable compound.

5. The method as recited in claim 1 wherein creating further includes forming said conformal layer from a material having a polymerizable compound and a surfactant having a surface energy that is lower than a surface energy of said polymerizable material.

6. The method as recited in claim 1 wherein creating further includes forming said patterned layer by disposing, on said substrate, a polymerizable fluid composition and contacting said polymerizable fluid composition with a surface of a mold, said surface having a profile complementary to said protrusions and said recessions, and subjecting said polymerizable fluid composition to conditions to polymerize said polymerizable fluid composition, forming a polymerized layer.

7. The method as recited in claim 1 wherein creating further includes forming said conformal layer by disposing, on said substrate, a polymerizable fluid composition and contacting said polymerizable fluid composition with a mold having a substantially planar surface and subjecting said polymerizable fluid composition to conditions to polymerize said polymerizable fluid composition.

8. The method as recited in claim 1 wherein forming said conformal layer further includes spin-coating a polymerizable fluid on said patterned layer.

9. The method as recited in claim 1 further including depositing a primer layer between said patterned layer and said substrate.

10. The method as recited in claim 1 wherein creating further includes forming said conformal layer with a section having a normalization surface disposed opposite to said patterned layer and spaced-apart from said protrusions, and further including removing portions of said section to expose said protrusions, defining said crown surface and exposing said crown surface to an etch chemistry.

11. The method as recited in claim 10 wherein removing portions further includes subjecting said normalization surface to a blanket etch and exposing said crown surface further includes subjecting said crown surface to an anisotropic plasma etch.

12. A method of patterning a substrate, said method comprising:

forming, on said substrate, a patterned layer, having protrusions and recessions, from a substantially silicon free polymerizble fluid employing imprint lithography techniques to form a silicon-free polymerized layer;

creating a conformal layer, adjacent to said silicon-free polymerized layer, from a silicon-containing polymerizable fluid employing imprint lithography techniques to form a silicon-containing polymerized layer having a normalization surface that faces away from said substrate; and

selectively removing portions of said silicon-containing polymerized layer and said silicon-free polymerized layer to expose regions of said substrate in superimposition with said protrusions while forming a hard mask in areas of said surface in superimposition with said recessions.

13. The method as recited in claim 12 wherein forming said patterned layer further includes providing said protrusions an apex and a height and creating said conformal layer further includes providing said conformal layer with a normalization surface spaced apart from one apex a minimum distance and spaced-apart from an additional apex a maximum distance with said height being greater than a difference between said maximum distance and said minimum distance.

14. The method as recited in claim 12 wherein creating further includes forming said patterned layer from a silicon-free fluid having an organic polymerizable compound and a surfactant having a surface energy that is lower than a surface energy of said organic polymerizable compound.

15. The method as recited in claim 14 wherein forming further includes forming said conformal layer from said silicon-containing fluid having an additional polymerizable compound and an additional surfactant having a low surface energy and a molecular weight that is less than a molecular weight of said additional polymerizable material.

16. The method as recited in claim 12 further including depositing a primer layer between said patterned layer and said substrate.

17. The method as recited in claim 12 wherein forming further includes disposing, on said substrate, a plurality of droplets of a first polymerizable fluid composition and contacting said first polymerizable fluid composition with a patterned surface of a patterned mold, said patterned surface having a profile complementary to said protrusions and said recessions, to spread said droplets over an area of said substrate to form a layer of first polymerizable fluid and subjecting said layer of first polymerizable fluid to conditions to polymerize said first polymerizable fluid composition, forming said patterned layer.

18. The method as recited in claim 17 wherein creating said conformal layer further includes spin-coating a polymerizable fluid on said patterned layer.

19. The method as recited in claim 17 wherein creating further includes forming said conformal layer by disposing, on said substrate, a second polymerizable fluid composition and contacting said second polymerizable fluid composition with a planarizing mold having a substantially planar surface and subjecting said second polymerizable fluid composition to conditions to polymerize said second polymerizable fluid composition.

20. The method as recited in claim 19 further including covering said patterned surface and said planar surface with a film having a low surface energy and forming each of said patterned mold and said planarized mold from fused silica.

21. The method as recited in claim 12 wherein creating further includes forming said conformal layer with a section having a normalization surface disposed opposite to said patterned layer and spaced-apart from said protrusions, and further including removing portions of said section to expose said protrusions, defining a crown surface and exposing said crown surface to an etch chemistry.

22. The method as recited in claim 21 wherein removing portions further includes subjecting said normalization surface to a blanket etch and exposing said crown surface further includes subjecting said crown surface to an anisotropic plasma etch.

23. A method of patterning a substrate, said method comprising:

forming, on said substrate a patterned layer, having protrusions and recessions, by depositing a silicon-free polymerizable fluid on said substrate and contacting said silicon-free polymerizable fluid with a first surface of a first mold, said first surface having a profile complementary to said protrusions and said recessions, and subjecting said silicon-free polymerizable fluid composition to conditions to polymerize said silicon-free polymerizable fluid composition, forming a silicon-free polymerized layer;

creating a conformal layer adjacent to said silicon-free polymerized layer by depositing a silicon-containing polymerizable fluid upon said patterned layer and contacting said silicon-containing polymerizable fluid composition with a second mold having a substantially planar surface and subjecting said silicon-containing polymerizable fluid composition to conditions to polymerize said silicon-containing polymerizable fluid composition, forming a planar silicon-containing polymerized layer; and

selectively removing said silicon-containing polymerized layer and said silicon-free polymerized layer to expose regions of said substrate in superimposition with said protrusions while densifying areas of said surface in superimposition with said recessions.

24. The method as recited in claim 23 further including depositing a primer layer between said patterned layer and said substrate.

25. The method as recited in claim 24 further including covering said patterned surface and said planar surface with a film having a low surface energy and forming each of said first mold and said second mold from fused silica.

26. The method as recited in claim 25 wherein said patterned layer and said conformal layer define a multi-layered structure and creating further includes forming said conformal layer with a section having a planar side disposed opposite to said patterned layer and spaced-apart from said protrusions, and further including removing portions of said section to expose said protrusions, defining a crown surface and exposing said crown surface to an oxygen plasma etch chemistry.

27. The method as recited in claim 27 wherein removing portions further includes subjecting said planar side to a blanket etch and exposing said crown surface further includes subjecting said crown surface to an anisotropic plasma etch.