Method for designing an illumination light source, method for designing a mask pattern, method for manufacturing a photomask, method for manufacturing a semiconductor device and a computer program product

• US 7,386,830 B2
• Filed: 08/23/2005
• Issued: 06/10/2008
• Est. Priority Date: 08/24/2004
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fukuhara, Kazuya
• Primary Examiner(s): Chiang; Jack
• Assistant Examiner(s): Memula; Suresh
• Application Number:
  US11/208,557
• Publication Number:
  US 20060046168A1
• Time in Patent Office: 1,022 Days
• Field of Search: 716 19- 21
• US Class Current: 716/53
• CPC Class Codes: G03F 7/701 Off-axis setting using an aperture
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

A method for designing an illumination light source, includes acquiring a control feature to control a dimension of a transferred pattern of a mask pattern; designating a plurality of illumination elements illuminating the mask pattern; designating first illumination lights to each of first polarization states of a light emitted from each of the illumination elements; calculating a first optical image of the control feature, formed on a first imaging plane by each of the first illumination lights; and determining an illumination shape and a polarization state distribution of the light, based on an optical characteristic of the first optical image.

Claims

1. A computer implemented method for designing an illumination light source, comprising:

acquiring a control feature configured to control a dimension of a transferred pattern of a mask pattern;

designating a plurality of illumination elements illuminating the mask pattern;

designating first illumination lights to each of first polarization states of a light emitted from each of the illumination elements;

calculating a first optical image of the control feature, the first optical image formed on a first imaging plane by each of the first illumination lights, the first imaging plane being a best focus plane;

determining optimal polarization states of the first illumination lights from among the first polarization states, based on an optical characteristic of the first optical image;

calculating a second optical image of the control feature, the second optical image formed on a second imaging plane by each of the first illumination lights, the second imaging plane being a defocus plane; and

determining an illumination shape and a polarization state distribution of the light, based on optical characteristics of the first and second optical images and the optimal polarization states.

2. The method of claim 1, further comprising:

designating second illumination lights to each of second polarization states of the light emitted from each of the illumination elements; and

calculating a third optical image of the control feature, the third optical image formed on the first imaging plane by each of the second illumination lights;

wherein, processing for determining the illumination shape and the polarization state distribution is based on optical characteristics of the first and second optical images.

3. The method of claim 1, wherein each of the optical characteristics is one of an image contrast of the first optical image and an image slope normalized by an image intensity at a pattern edge of the first optical image.

4. The method of claim 1, wherein the mask pattern periodically arranges the control feature in a period direction.

5. The method of claim 4, wherein the first polarization state is a linear polarization having a polarization direction orthogonal to the period direction.

6. The method of claim 1, wherein the defocus plane is provided at a depth of focus end.

7. The method of claim 1, wherein the first optical image is calculated by a light source group which is a set of illumination elements in symmetrical positions with respect to an optical axis orthogonal to a plane of the illumination elements.

8. The method of claim 1, wherein the illumination shape and the polarization state distribution are determined by extracting the illumination elements providing a calculated value of each of the optical characteristics equal to or less than a reference value.

9. A computer implemented method for correcting a mask pattern, comprising:

acquiring a control feature configured to control a dimension of a transferred pattern of a mask pattern;

designating a plurality of illumination elements illuminating the mask pattern;

designating first illumination lights to each of first polarization states of a light emitted from each of the illumination elements;

calculating a first optical image of the control feature, the first optical image formed on a first imaging plane by each of the first illumination lights, the first imaging plane being a best focus plane;

determining optimal polarization states of the first illumination lights from among the first polarization states, based on an optical characteristic of the first optical image;

calculating a second optical image of the control feature, the second optical image formed on a second imaging plane by each of the first illumination lights, the second imaging plane being a defocus plane;

providing an illumination light source by determining an illumination shape and a polarization state distribution of the light, based on optical characteristics of the first and second optical image images and the optimal polarization states; and

calculating a dimensional variation of the transferred pattern by the illumination light source so as to correct the mask pattern.

10. The method of claim 9, further comprising:

designating second illumination lights to each of second polarization states of the light emitted from each of the illumination elements; and

calculating a third optical image of the control feature, the third optical image formed on the first imaging plane by each of the second illumination lights;

wherein, processing for determining the illumination shape and the polarization state distribution is based on optical characteristics of the first to third optical images.

11. The method of claim 9, wherein each of the optical characteristics is one of an image contrast of the first optical image and an image slope normalized by an image intensity at a pattern edge of the first optical image.

12. The method of claim 9, wherein the mask pattern periodically arranges the control feature in a period direction.

13. The method of claim 12, wherein the first polarization state is a linear polarization having a polarization direction orthogonal to the period direction.

14. The method of claim 9, wherein the first optical image is calculated by a light source group which is a set of illumination elements in symmetrical positions with respect to an optical axis orthogonal to a plane of the illumination elements.

15. The method of claim 9, wherein the illumination shape and the polarization state distribution are determined by extracting the illumination elements providing a calculated value of each of the optical characteristics equal to or less than a reference value.

16. A method for manufacturing a photomask, comprising:

acquiring a control feature configured to control a dimension of a transferred pattern of a mask pattern;

designating a plurality of illumination elements illuminating the mask pattern;

designating first illumination lights to each of first polarization states of a light emitted from each of the illumination elements;

calculating a first optical image of the control feature, the first optical image formed on a first imaging plane by each of the first illumination lights, the first imaging plane being a best focus plane;

determining optimal polarization states of the first illumination lights from among the first polarization states, based on an optical characteristic of the first optical image;

calculating a second optical image of the control feature, the second optical image formed on a second imaging plane by each of the first illumination lights, the second imaging plane being a defocus plane;

providing an illumination light source by determining an illumination shape and a polarization state distribution of the light, based on optical characteristics of the first and second optical images and the optimal polarization states;

calculating a dimensional variation of the transferred pattern by the illumination light source so as to correct the mask pattern; and

generating the photomask based on the corrected mask pattern.

17. A method for manufacturing a semiconductor device, comprising:

acquiring a control feature configured to control a dimension of a transferred pattern of a mask pattern;

designating a plurality of illumination elements illuminating the mask pattern;

designating first illumination lights to each of first polarization states of a light emitted from each of the illumination elements;

calculating a first optical image of the control feature, the first optical image formed on a first imaging plane by each of the first illumination lights, the first imaging plane being a best focus plane;

determining optimal polarization states of the first illumination lights from among the first polarization states, based on an optical characteristic of the first optical image;

calculating a second optical image of the control feature, the second optical image formed on a second imaging plane by each of the first illumination lights, the second imaging plane being a defocus plane;

providing an illumination light source by determining an illumination shape and a polarization state distribution of the light, based on optical characteristics of the first and second optical images and the optimal polarization states;

calculating a dimensional variation of the transferred pattern by the illumination light source so as to correct the mask pattern;

generating a photomask based on the corrected mask pattern;

adjusting an exposure tool, based on the illumination light source;

loading a semiconductor substrate coated with a resist film to the exposure tool; and

projecting an image of the photomask onto the semiconductor substrate, so as to transfer the corrected mask pattern on the resist film, and to form a resist pattern.

18. A computer program product stored on a computer-readable medium of a computer and configured to be executed by the computer, comprising:

an instruction to acquire a control feature configured to control a dimension of a transferred pattern of a mask pattern;

an instruction to designate a plurality of illumination elements illuminating the mask pattern;

an instruction to designate first illumination lights to each of first polarization states of a light emitted from each of the illumination elements;

an instruction to calculate a first optical image of the control feature, the first optical image formed on a first imaging plane by each of the first illumination lights, the first imaging plane being a best focus plane;

an instruction to determine optimal polarization states of the first illumination lights from among the first polarization states, based on an optical characteristic of the first optical image;

an instruction to calculate a second optical image of the control feature, the second optical image formed on a second imaging plane by each of the first illumination lights, the second imaging plane being a defocus plane; and

an instruction to determine an illumination shape and a polarization state distribution of the light, based on optical characteristics of the first and second optical images and the optimal polarization states.