Method for improved lithographic patterning utilizing multiple coherency optimized exposures and high transmission attenuated PSM

• US 20050186491A1
• Filed: 04/19/2005
• Published: 08/25/2005
• Est. Priority Date: 08/21/2001
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Masktools B.V. (ASML Holding NV)
• Inventors: Laidig, Thomas, Chen, Jang Fung, Broeke, Douglas Van Den, Hsu, Stephen, Hsu, Michael
• Granted Patent: US 7,523,438 B2
• Time in Patent Office: Days
• US Class Current: 430/30
• CPC Class Codes: G03F 1/32 Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof
• CPC Class Codes: G03F 7/70091 Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]
• 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 7/70283 Mask effects on the imaging process
• 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
• CPC Class Codes: G03F 7/70591 Testing optical components

Abstract

A method for optically transferring a lithographic pattern corresponding to an integrated circuit utilizing a high transmission attenuated phase-shift mask onto a semiconductor substrate by use of an optical exposure tool. The method comprising the steps of generating a diffraction pattern corresponding to the lithographic pattern, where the diffraction pattern indicates a plurality of spatial frequency components corresponding to the lithographic pattern; determining which of the spatial frequency components need to be captured by a lens in the optical exposure tool in order to accurately reproduce the lithographic pattern; determining a set of illumination conditions required for the optical exposure tool to capture the spatial frequency components necessary for accurately reproducing the lithographic pattern; and illuminating the high transmission attenuated phase-shift mask with this set of illumination conditions.

Claims

1-8. -8. (canceled)

9. A computer program product for controlling a computer comprising a recording medium readable by the computer, means recorded on the recording medium for directing the computer to control an optical exposure tool for optically transferring a lithographic pattern corresponding to an integrated circuit utilizing a high transmission attenuated phase-shift mask onto a semiconductor substrate by use of an optical exposure tool, the transfer method comprising the steps of

generating a diffraction pattern corresponding to said lithographic pattern, said diffraction pattern indicating a plurality of spatial frequency components corresponding to said lithographic pattern;

determining which of said spatial frequency components need to be captured by a lens in said optical exposure tool in order to accurately reproduce said lithographic pattern;

determining a set of illumination conditions required for said optical exposure tool to capture said spatial frequency components necessary for accurately reproducing said lithographic pattern; and

illuminating said a high transmission attenuated phase-shift mask with said set of said illumination conditions.

10. A computer program product according to claim 9, wherein said high transmission attenuated phase-shift mask is a 100% transmission attenuated phase-shift mask.

11. A computer program product according to claim 10, wherein said set of illumination conditions comprises a plurality of distinct illumination conditions, said high transmission attenuated phase-shift mask being illuminated per each distinct illumination condition.

12. A computer program product according to claim 11, wherein each of said distinct illumination conditions includes a different coherency exposure setting.

13. A computer program product according to claim 10, wherein said optical exposure tool utilizes off-axis illumination.

14. A computer program product according to claim 10, wherein said transfer method further comprises the steps of:

analyzing said diffraction pattern so as to identify spatial frequency components that detract from the accuracy of the lithographic pattern transferred to said semiconductor substrate, and

determining said illumination conditions necessary to prevent said spatial frequency components that detract from the accuracy of the lithographic pattern from being captured by said optical exposure tool.

15. A computer program product according to claim 10, wherein said transfer method further comprises the step of modifying the diffraction pattern so as to eliminate spatial frequency components which negatively effect the accurate reproduction of said lithographic pattern.

16. A computer program product according to claim 10, wherein said transfer method further comprises the step of blocking the exposure energy associated with at least one spatial frequency component which negatively effects the accurate reproduction of said lithographic pattern, so as to prevent said spatial frequency component from reaching said substrate.

17-19. -19. (canceled)

20. A computer program product for controlling a computer comprising a recording medium readable by the computer, means recorded on the recording medium for directing the computer to generate files corresponding to a mask utilized in the process of optically transferring a lithographic pattern corresponding to an integrated circuit onto a semiconductor substrate by use of an optical exposure tool, the transfer method comprising the steps of:

generating a diffraction pattern corresponding to a lithographic pattern to be imaged, said diffraction pattern indicating a plurality of spatial frequency components corresponding to said lithographic pattern;

determining which of said spatial frequency components need to be captured by a lens in an optical exposure tool in order to accurately reproduce said lithographic pattern; and

forming a reticle having a pattern which allows said spatial frequency components to be captured to be imaged on a substrate.

21. A computer program product according to claim 20, wherein said reticle blocks exposure energy associated with at least one spatial frequency component which negatively effects the accurate reproduction of said lithographic pattern, so as to prevent said spatial frequency component from reaching said substrate.