Method for improved lithographic patterning utilizing optimized illumination conditions and high transmission attenuated PSM
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.
1. 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 perform 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 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 high transmission attenuated phase-shift mask with said set of said illumination conditions.
2. The computer program product according to claim 1 , wherein said high transmission attenuated phase-shift mask is a 100% transmission attenuated phase-shift mask.
3. The computer program product according to claim 2 , 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.
4. The computer program product according to claim 3 , wherein each of said distinct illumination conditions includes a different coherency exposure setting.
5. The computer program product according to claim 2 , wherein said optical exposure tool utilizes off-axis illumination.
6. The computer program product according to claim 2 , 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.
7. The computer program product according to claim 2 , 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.
8. The computer program product according to claim 2 , 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.
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 perform a method of optically transferring a lithographic pattern corresponding to an integrated circuit onto a semiconductor substrate by use of an optical exposure tool, said method comprising the steps of:
generating a diffraction pattern corresponding to the 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 high transmission attenuated phase-shift reticle having a pattern which allows said spatial frequency components to be captured to be imaged on a substrate.
10. The computer program product according to claim 9 , 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.