Lithography process

Patent metadata

Field	Value
Publication number	US-9429839-B2
Application number	US-201214111362-A
Country	US
Kind code	B2
Filing date	Apr 12, 2012
Priority date	Apr 12, 2011
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

A lithography method including: a preparation, during which a resist layer is deposited on a substrate, and a preliminary lithography carried out to define at least one preliminary pattern in the resist layer, and during the preliminary lithography, a formation of at least one positioning mark forming a relief in the resist layer. The method further includes at least one subsequent lithography applied to the resist layer and including: a preliminary positioning including positioning a lithography mechanism as a function of the at least one positioning mark, and at least one formation of additional patterns in the resist layer using the lithography mechanism positioned as a function of the at least one positioning mark.

First claim

The invention claimed is:

1. A lithography method comprising:
a preparation, during which a resist layer is deposited on a substrate;
a preliminary lithography carried out to define at least one preliminary pattern in the resist layer, wherein the preliminary lithography comprises nanoimprinting, during which a mold provided with reliefs penetrates into the resist layer to generate in a single step the at least one preliminary pattern and at least one positioning mark forming a pattern in the resist layer, at least some of the patterns generated by the mold having different depths; and
at least one subsequent lithography applied to the resist layer and including:
a preliminary positioning including positioning a lithography apparatus as a function of the at least one positioning mark;
at least one formation of additional patterns in the resist layer using the lithography apparatus positioned as a function of the at least one positioning mark, the formation of the additional patterns comprising exposure of at least part of a preliminary pattern,
wherein the preliminary lithography defines first zones having a first thickness and second zones each having a thickness smaller than the first thickness, and wherein the at least one subsequent lithography is carried out to make the resist layer disappear at least partly at least some of the second zones.

2. A method according to claim 1 , wherein the formation of additional patterns is carried out to superpose the preliminary pattern with an additional pattern to form in the resist layer at least one final hollow pattern having at least two levels of depth in the resist layer.

3. A method according to claim 1 , wherein the formation of additional patterns is carried out to form in the resist layer at least one final projecting pattern having at least two levels of height.

4. A method according to claim 1 , wherein the positioning comprises detection of the positioning marks by light diffraction.

5. A method according to claim 1 , wherein at least one among the additional patterns is separated from the at least one preliminary pattern.

6. A method according to claim 1 , further comprising, following the at least one subsequent lithography, a transfer including transferring the at least one preliminary pattern and the additional patterns from the resist layer into the substrate.

7. A method according to claim 1 , wherein the at least one positioning mark is preserved at the end of the at least one subsequent lithography.

8. A method according to claim 7 , wherein the at least one positioning mark is transferred from the resist layer into the substrate.

9. A method according to claim 6 , wherein the at least one positioning mark is eliminated during the at least one subsequent lithography.

10. A method according to claim 6 , wherein the transfer comprises etching the resist layer and the substrate, the etching having substantially identical selectivity for the resist layer and for the substrate.

11. A method according to claim 6 , wherein the transfer is executed to transfer the at least one final pattern from the resist layer into the substrate to form in the substrate at least one final three-dimensional pattern having two levels of etching depth.

12. A method according to claim 11 , further comprising supplying an electrically conductive material into the at least one final pattern.

13. A method according to claim 12 , wherein, prior to the preparation, at least one layer of an integrated circuit is formed in the substrate, and wherein the transfer and the supplying are executed so that the electrically conductive material forms a line and a vertical interconnection connecting the line to the at least one layer of the integrated circuit.

14. A method according to claim 1 , wherein the resist layer includes a photosensitive resist, wherein the formation of additional patterns in the resist layer comprises photolithography, and wherein the exposure comprises irradiation of one part at least of the at least one preliminary pattern.

15. A method according to claim 1 , wherein the formation of additional patterns in the resist layer comprises electron-beam lithography or ion-beam lithography, and wherein the exposure comprises writing of one part at least of the at least one preliminary pattern.

16. A method according to claim 14 , wherein the nanoimprinting is carried out so that a residue of resist is made to appear at a bottom of a hollow formed by the preliminary pattern, and wherein the formation of additional patterns is carried out to make the resist residues at the bottom of the hollow disappear or to create, in the resist residue, at least one opening extending from the hollow to the substrate.

17. A method according to claim 16 , wherein the resist is a positive photosensitive resist, wherein the subsequent lithography comprises photolithography comprising irradiation carried out to irradiate the resist residue at least partly to make the resist residue at the bottom of the hollow disappear or to create at least one opening extending from the hollow to the substrate.

18. A method according to claim 1 , comprising plural subsequent lithographies, each comprising formation of additional patterns, a first subsequent lithography comprising photolithography and a second subsequent lithography comprising one among: photolithography, electron-beam lithography, ion-beam lithography.

19. A method according to claim 1 , wherein the preliminary patterns have a depth different from a depth of the positioning marks.

20. A method according to claim 1 , wherein the preliminary patterns have a depth smaller than a depth of the positioning marks.

21. A method according to claim 1 , wherein the depth of all the positioning marks is identical and a depth of all the preliminary patterns is identical.

22. A method according to claim 1 , wherein the mold includes reliefs having plural heights for defining preliminary patterns of different depths.

23. A lithography method comprising:
a preparation, during which a resist layer is deposited on a substrate;
a preliminary lithography carried out to define at least one preliminary pattern in the resist layer, wherein the preliminary lithography comprises nanoimprinting, during which a mold provided with reliefs penetrates into the resist layer to generate in a single step the at least one preliminary pattern and at least one positioning mark forming a pattern in the resist layer, at least some of the patterns generated by the mold having different depths; and
at least one subsequent lithography applied to the resist layer and including:
a preliminary positioning including positioning a lithography apparatus as a function of the at least one positioning mark; and
at least one formation of additional patterns in the resist layer using the lithography apparatus positioned as a function of the at least one positioning mark, the formation of the additional patterns comprising exposure of at least part of a preliminary pattern,
wherein
the resist layer includes a positive photosensitive resist, wherein the formation of additional patterns in the resist layer comprises photolithography,
the exposure comprises irradiation of one part at least of the at least one preliminary pattern,
the nanoimprinting is carried out so that a residue of resist is made to appear at a bottom of a hollow formed by the preliminary pattern, and
the subsequent lithography comprises photolithography comprising i

Assignees

• Pauliac Sebastien
• Commissariat Energie Atomique

Inventors

• Pauliac Sebastien

Classifications

• G03F7/0002

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

• G03F7/70466

  Multiple exposures, e.g. combination of fine and coarse exposures, double patterning or multiple exposures for printing a single feature (stitching G03F7/70475) · CPC title

• G03F9/7076

  Mark details, e.g. phase grating mark, temporary mark · CPC title

• G03F9/708

  Mark formation · CPC title

• B82Y10/00 Primary

  Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic · CPC title