Subresolution grating for attenuated phase shifting mask fabrication
First Claim
Patent Images
1. A method of fabricating a photomask, comprising:
- preparing a plate;
transferring a primary pattern onto the plate, the primary pattern including an edge circumscribing the primary pattern; and
fabricating a plurality of approximately round contacts in the edge of the primary pattern.
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Accused Products
Abstract
A subresolution grating composed of approximately circular contacts is fabricated around the border of the primary pattern of a photomask. As a result, resolution at the edges of the photomask pattern is improved when the pattern is printed on a wafer surface. In addition, the reduced leakage enables a more efficient use of the glass plate on which the photomask is fabricated as well as a more efficient use of the wafer surface as a result of being able to place patterns closer together.
41 Citations
34 Claims
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1. A method of fabricating a photomask, comprising:
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preparing a plate;
transferring a primary pattern onto the plate, the primary pattern including an edge circumscribing the primary pattern; and
fabricating a plurality of approximately round contacts in the edge of the primary pattern.
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2. A photomask, comprising:
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a photolithographic pattern;
a border outlining the pattern; and
a plurality of approximately circular contacts in the border outlining the pattern.
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3. A photomask, comprising:
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a photolithographic, phase-shifting pattern formed with attenuating material, including a border circumscribing the phase-shifting pattern;
a plurality of octagonal contacts formed in the border.
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4. A method of fabricating a photomask, comprising the steps of:
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preparing a glass plate;
transferring a pattern onto the glass plate, the pattern including a circumscribing edge; and
fabricating a plurality of approximately round contacts in the edge. - View Dependent Claims (5, 6, 33)
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7. A method of fabricating a photomask, comprising:
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preparing a transparent plate;
selectively depositing attenuating material on the transparent plate to form a pattern, the pattern including an edge circumscribing the pattern; and
fabricating a plurality of octagonal contacts in the edge. - View Dependent Claims (8, 9, 34)
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10. A photomask, comprising:
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a pattern;
a border outlining the pattern; and
a plurality of approximately circular contacts in the border outlining the pattern. - View Dependent Claims (11, 12, 13)
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14. A photomask produced by a method, comprising:
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preparing a plate;
selectively depositing attenuating material on the plate to form a pattern, the primary pattern including an edge circumscribing the pattern; and
fabricating a plurality of octagonal contacts in the edge of the pattern.
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15. A subresolution grating, comprising:
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a border outlining a pattern of a photomask; and
a plurality of approximately circular contacts in the border outlining the pattern. - View Dependent Claims (16, 17)
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18. A photomask, comprising:
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a pattern; and
a diffraction grating about the pattern, the diffraction grating including contact shapes approximating a circle, the contact shapes being less than 0.11 microns in diameter. - View Dependent Claims (19)
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20. A photomask, comprising:
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a pattern; and
a diffraction grating outside the pattern, the diffraction grating having octagonal contacts each with a diameter, the octagonal contacts being separated from each other by a distance substantially equal to the diameter. - View Dependent Claims (21, 22)
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23. A photomask, comprising:
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a pattern; and
a diffraction grating outside the pattern, the diffraction grating including approximately circular contacts having substantially equal diameters and distances therebetween, the diameters and distances being less than 0.11 microns. - View Dependent Claims (24)
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- 25. A method of fabricating a border surrounding a photomask pattern, comprising depositing a pattern of attenuating material in the border of a photomask, the pattern including substantially circular contact shapes having a diameter of less than 0.11 micron.
- 27. A method of fabricating a border surrounding a photomask pattern, comprising depositing a pattern of attenuating material in the border of a photomask, the pattern including contact shapes that approximate a circle having a diameter of less than 0.11 micron.
- 29. A method of fabricating a border surrounding a photomask pattern, comprising depositing a pattern of attenuating material in the border of the photomask, the pattern including octagonal contact shapes.
- 31. A method of projecting a pattern on a wafer comprising projecting light through a photomask having a diffraction grating about a perimeter of a pattern, the diffraction grating comprising octagonal contacts.
Specification