Nanoimprint lithography

• US 5,772,905 A
• Filed: 11/15/1995
• Issued: 06/30/1998
• Est. Priority Date: 11/15/1995
• Status: Expired due to Term

• Current Assignee: Regents of The University of Minnesota (University of Minnesota)
• Original Assignee: Regents of The University of Minnesota (University of Minnesota)
• Inventors: Chou, Stephen Y.
• Primary Examiner(s): Breneman, R. Bruce
• Assistant Examiner(s): ALANKO, ANITA KAREN
• Application Number:
  US08/558,809
• Time in Patent Office: 958 Days
• Field of Search: 216/11, 216/40, 216/44, 216/52, 216/53, 216/58, 216/83, 438/691, 438/700, 438/735
• US Class Current: 216/44
• CPC Class Codes: B29C 2059/023 Microembossing
• CPC Class Codes: B29C 59/022 characterised by the disposition or the configuration, e.g. dimensions, of the embossments or the shaping tools therefor
• CPC Class Codes: B29C 59/026 of layered or coated substantially flat surfaces
• 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: G03F 9/7053 Non-optical, e.g. mechanical, capacitive, using an electron beam, acoustic or thermal waves
• CPC Class Codes: Y10S 977/887 Nanoimprint lithography, i.e. nanostamp

Abstract

A lithographic method and apparatus for creating ultra-fine (sub-25 nm) patterns in a thin film coated on a substrate is provided, in which a mold having at least one protruding feature is pressed into a thin film carried on a substrate. The protruding feature in the mold creates a recess of the thin film. The mold is removed from the film. The thin film then is processed such that the thin film in the recess is removed exposing the underlying substrate. Thus, the patterns in the mold is replaced in the thin film, completing the lithography. The patterns in the thin film will be, in subsequent processes, reproduced in the substrate or in another material which is added onto the substrate.

Claims

1. A lithographic method for forming a pattern in a film carried on a substrate, comprising the steps of:

obtaining a substrate;

depositing a film on the substrate;

obtaining a mold of a stiff material which is hard relative to the film, the mold having a first protruding feature and a recess formed thereby and a second protruding feature spaced apart prom the first protruding feature, the first and second features and the recess having a shape forming a mold pattern and providing at least one mold pattern lateral dimension which is less than 200 nm;

urging the mold at a molding pressure into the film whereby the thickness of the film under the protruding feature is reduced and a thin region is formed in the film, wherein the molding pressure is sufficiently high to transfer the mold pattern to the film and the molding pressure causes a local deformation in the mold which is less than the mold pattern lateral dimension;

removing the mold from the film;

processing the relief whereby the thin region is removed exposing portions of the surface of the substrate which underlie the thin region; and

whereby the exposed portions of the surface of the substrate substantially replicate the mold pattern and have at least one lateral dimension which is less than 200 nm.

2. The method of claim 1 wherein the thin film comprises a thermoplastic polymer.

3. The method of claim 1 including heating the thin film to a temperature to allow sufficient softening of the film relative to the mold prior to the step of urging.

4. The method of claim 1 wherein the features on the mold are formed from material selected from the group consisting of:

semiconductors, dielectrics, metals, and their combination.

5. The method of claim 1 wherein the step of urging comprises pressing the mold into the thin film without allowing the features to contact the underlying substrate.

6. The method of claim 1 wherein the step of processing comprises reactive ion etching.

7. The method of claim 1 including repeating the steps of obtaining a mold, urging, removing, and processing to form a multilayered device.

8. The method of claim 1 including the step of aligning the features on the mold with a pattern on the substrate.

9. The method of claim 1 including the step of depositing a material on the exposed portion of the substrate.

10. The method of claim 9 wherein the material is selected from the group consisting of semiconductors, dielectrics, metals, and their combination.

11. The method of claim 9 including selectively removing the film following depositing the material.

12. The method of claim 11 wherein the step of selectively removing the film comprises a lift off process.

13. The method of claim 1 including removing the exposed portion of the substrate to form a recess in the substrate.

14. A lithographic method for forming a pattern in a film carried on a substrate, comprising the steps;

obtaining a substrate;

depositing a thin film on the substrate;

obtaining a mold of a stiff material which is hard relative to the film, the mold having a first feature and a second feature, the first feature spaced apart from the second feature, the first and second features forming a mold pattern having at least one mold pattern lateral dimension which is less than 200 nm;

molding the film with the features of the mold to form thin regions in the film shaped by the features by pressing the mold into the film at a molding pressure, wherein the pressure is sufficiently high to transfer the features to the film and the molding pressure causes a local deformation in the mold which is less than the mold pattern lateral dimension; and

removing the thin region of the film exposing portions of the substrate underlying the thin regions thereby patterning the substrate with the feature to form a pattern which has at least one lateral dimension which is less than 200 nm.

15. The method of claim 14 including the step of depositing a material on the exposed portion of the substrate.

16. The method of claim 14 including removing the exposed portion of the substrate to form a recess in the substrate.

17. The method of claim 14 including repeating the steps of obtaining a mold, molding and removing to form a multilayered device.

18. The method of claim 14 including the step of aligning the features on the mold with a pattern on the substrate.

19. A lithographic method for forming a pattern in a film carried on a substrate, comprising the steps of:

obtaining a substrate;

depositing a film on the substrate;

obtaining a mold of a stiff material which is hard relative to the film, the mold having a first protruding feature and a recess formed thereby, and a second protruding feature spaced apart from the first protruding feature, the features and the recess having a shape forming a mold pattern with at least one mold pattern lateral dimension which is less than 200 nm;

urging the mold at a molding pressure into the film creating a thickness contrast pattern in the film, wherein the molding pressure is sufficiently high to transfer the features to the film and the molding pressure causes a local deformation in the mold which is less than the mold pattern lateral dimension;

removing the mold from the film; and

transferring the thickness contrast pattern in the film onto the substrate wherein the thickness contrast has at least one lateral dimension which is less than 200 nm.