Optical proximity correction method utilizing phase-edges as sub-resolution assist features

• US 7,026,081 B2
• Filed: 05/23/2002
• Issued: 04/11/2006
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Masktools B.V. (ASML Holding NV)
• Inventors: Van Den Broeke, Douglas, Chen, J. Fung
• Primary Examiner(s): Huff, Mark F.
• Assistant Examiner(s): Mohamedulla, Saleha
• Application Number:
  US10/152,686
• Publication Number:
  US 20030064298A1
• Time in Patent Office: 1,419 Days
• Field of Search: 430/5, 430/396, 430/313, 430/311, 430/312, 430/30
• US Class Current: 430/30
• CPC Class Codes: G03F 1/26 Phase shift masks [PSM]; PSM blanks; Preparation thereof
• CPC Class Codes: G03F 1/34 Phase-edge PSM, e.g. chromeless PSM; Preparation thereof
• CPC Class Codes: G03F 1/36 Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes

Abstract

A photolithography mask for optically transferring a pattern formed in the mask onto a substrate and for negating optical proximity effects. The mask includes a plurality of resolvable features to be printed on the substrate, and at least one non-resolvable optical proximity correction feature, where the non-resolvable optical proximity correction feature is a phase-edge.

Claims

1. A method of transferring a lithographic pattern from a photography mask onto a substrate by use of a lithographic exposure apparatus, said method comprising the steps of:

forming a plurality of resolvable features to be printed on said substrate; and

forming at least one non-resolvable optical proximity correction feature, said at least one non-resolvable optical proximity correction feature being a phase-edge,

wherein said at least one non-resolvable phase-edge is the sole optical proximity correction feature positioned between a first resolvable feature and a second resolvable feature.

2. The method of claim 1, wherein said phase-edge has a width dimension substantially equal to zero.

3. The method of claim 1, wherein said phase-edge effects a phase-shift of greater than 0°

.

4. The method of claim 1, wherein said phase-edge effects a phase-shift of 180°

.

5. The method of claim 1, wherein said mask is illuminated utilizing off-axis illumination.

7. The method of claim 1, wherein said mask comprises a quartz substrate, said at least one non-resolvable phase-edge being formed by etching said quartz substrate.

8. The method of claim 1, wherein said mask forms a chromeless phase-shift mask.

9. The method of claim 1, wherein said non-resolvable feature is spaced apart from said given one of said resolvable features so as to maximize the depth of focus of an imaging system for a given feature size.

10. The method of claim 1, wherein the phase-shift effected by said phase-edge is selected so as to maintain said phase-edge sub-resolution.

6. A device manufacturing method comprising the steps of:

(a) providing a substrate that is at least partially covered by a layer of radiation-sensitive material;

(b) providing a projection beam of radiation using a radiation system;

(c) using a pattern on a mask to endow the projection beam with a pattern in its cross-section;

(d) projecting the patterned beam of radiation onto a target portion of the layer of radiation-sensitive material,

wherein, in step (c), use is made of a mask comprising;

a plurality of resolvable features to be printed on said substrate; and

at least one non-resolvable optical proximity correction feature, said at least one non-resolvable optical proximity correction feature being a phase-edge;

wherein said at least one non-resolvable phase-edge is the sole optical proximity correction feature positioned between a first resolvable feature and a second resolvable feature.

11. The device manufacturing method of claim 6, wherein said phase-edge has a width dimension substantially equal to zero.

12. The device manufacturing method of claim 6, wherein said phase-edge effects a phase-shift of greater than 0°

.

13. The device manufacturing method of claim 6, wherein said phase-edge effects a phase-shift of 180°

.

14. The device manufacturing method of claim 6, wherein said mask forms a chromeless phase-shift mask.

15. The device manufacturing method of claim 6, wherein said non-resolvable feature is spaced apart from said given one of said resolvable features so as to maximize the depth of focus of an imaging system for a given feature size.

16. The device manufacturing method of claim 6, wherein the phase-shift effected by said phase-edge is selected so as to maintain said phase-edge sub-resolution.

17. The device manufacturing method of claim 6, wherein said mask is illuminated utilizing off-axis illumination.

18. The device manufacturing method of claim 6, wherein said mask comprises a quartz substrate, said at least one non-resolvable phase-edge being formed by etching said quartz substrate.