Method and apparatus for performing dark field double dipole lithography (DDL)

• US 20080020296A1
• Filed: 04/06/2007
• Published: 01/24/2008
• Est. Priority Date: 04/06/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Masktools B.V. (ASML Holding NV)
• Inventors: Chen, Jang, Hsu, Duan-Fu, Park, Sangbong, Van Den Broeke, Douglas
• Granted Patent: US 7,824,826 B2
• Time in Patent Office: Days
• US Class Current: 430/5
• CPC Class Codes: G03F 1/36 Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes
• CPC Class Codes: G03F 1/70 Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging
• CPC Class Codes: G03F 7/70125 Use of illumination settings tailored to particular mask patterns details of setting means G03F7/70091
• CPC Class Codes: G03F 7/70466 Multiple exposures, e.g. combination of fine and coarse exposures, double patterning or multiple exposures for printing a single feature stitching G03F7/70475

Abstract

A method of generating complementary masks for use in a dark field double dipole imaging process. The method includes the steps of identifying a target pattern having a plurality of features, including horizontal and vertical features; generating a horizontal mask based on the target pattern, where the horizontal mask includes low contrast vertical features. The generation of the horizontal mask includes the steps of optimizing the bias of the low contrast vertical features contained in the horizontal mask; and applying assist features to the horizontal mask. The method further includes generating a vertical mask based on the target pattern, where the vertical mask contains low contrast horizontal features. The generation of the vertical mask includes the steps of optimizing the bias of low contrast horizontal features contained in the vertical mask; and applying assist features to the vertical mask.

Claims

1. A method of generating complementary masks for use in a dark field double dipole imaging process, said method comprising the steps of:

identifying a target pattern having a plurality of features, said plurality of features comprising horizontal and vertical features,

generating a horizontal mask based on said target pattern, said horizontal mask including low contrast features, said generation of said horizontal mask comprising the steps of;

optimizing the bias of said low contrast features contained in said horizontal mask; and

applying assist features to said horizontal mask; and

generating a vertical mask based on said target pattern, said vertical mask containing low contrast features, said generation of said vertical mask comprising the steps of;

optimizing the bias of low contrast features contained in said vertical mask;

applying assist features to said vertical mask.

2. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 1, wherein said step of optimizing the bias of said low contrast features includes the step of adjusting the width of the vertical features contained in said horizontal mask so as to maximize a predefined criteria associated with imaging performance.

3. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 1, wherein the step of generating a horizontal mask further includes the step of re-performing the step of optimizing the bias of said low contrast features after the step of applying said assist features to said horizontal mask.

4. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 1, wherein the step of generating a horizontal mask further includes the step of performing model OPC on said horizontal mask.

5. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 1, wherein said step of optimizing the bias of said low contrast features includes the step of adjusting the width of the horizontal features contained in said vertical mask so as to maximize a predefined criteria associated with imaging performance.

6. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 1, wherein the step of generating said vertical mask further includes the step of re-performing the step of optimizing the bias of said low contrast features after the step of applying said assist features to said vertical mask.

7. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 1, wherein the step of generating a vertical mask further includes the step of performing model OPC on said vertical mask.

15. 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 patterning means 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 the patterning means of step (c) is generated using a method according to claim 1.

8. A computer readable medium configured to store program instructions for execution by a processor, said program instructions enabling the processor to generate files corresponding to complementary masks for use in a dark field double dipole imaging process, said generation of said files comprising the steps of:

identifying a target pattern having a plurality of features, said plurality of features comprising horizontal and vertical features,

generating a horizontal mask based on said target pattern, said horizontal mask including low contrast features, said generation of said horizontal mask comprising the steps of;

optimizing the bias of said low contrast features contained in said horizontal mask; and

applying assist features to said horizontal mask; and

generating a vertical mask based on said target pattern, said vertical mask containing low contrast features, said generation of said vertical mask comprising the steps of;

optimizing the bias of low contrast features contained in said vertical mask;

applying assist features to said vertical mask.

9. The computer readable medium according to claim 8, wherein said step of optimizing the bias of said low contrast features includes the step of adjusting the width of the vertical features contained in said horizontal mask so as to maximize a predefined criteria associated with imaging performance.

10. The computer readable medium according to claim 8, wherein the step of generating a horizontal mask further includes the step of re-performing the step of optimizing the bias of said low contrast features after the step of applying said assist features to said horizontal mask.

11. The computer readable medium according to claim 8, wherein the step of generating a horizontal mask further includes the step of performing model OPC on said horizontal mask.

12. The computer readable medium according to claim 8, wherein said step of optimizing the bias of said low contrast features includes the step of adjusting the width of the horizontal features contained in said vertical mask so as to maximize a predefined criteria associated with imaging performance.

13. The computer readable medium according to claim 8, wherein the step of generating said vertical mask further includes the step of re-performing the step of optimizing the bias of said low contrast features after the step of applying said assist features to said vertical mask.

14. The computer readable medium according to claim 8, wherein the step of generating a vertical mask further includes the step of performing model OPC on said vertical mask.