Photomask, method of making a photomask and photolithography method and system using the same
First Claim
1. A photomask, comprising:
- a substrate having a first region and a second region; and
a polarizing structure formed in the substrate in one of the first and second regions, such that when radiation of a first illumination type impinges on the substrate and the polarizing structure, radiation of a second illumination type is formed in the one of the first and second regions and radiation of a third illumination type is formed in the other of the first and second regions.
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Accused Products
Abstract
A photomask according to the invention provides selective regional optimization of illumination type according to the type of image being formed using the photomask. The photomask include a light polarizing structure which polarizes the light incident on the polarizing structure. Light of a first illumination type from a source in a photolithographic exposure system is incident on the photomask. A portion of the light is incident on the region of the photomask that includes the polarizing structure, and another portion of the light is incident on another region of the photomask that does not include a polarizing structure. The illumination type of the light incident on the polarizing structure is changed to a second illumination type such that light incident on a substrate such as an integrated circuit wafer from the region of the photomask that has the polarizing structure is of the second illumination type. The illumination type of the portion of the light that is not incident on the polarizing structure is not changed, such that light from that portion of the photomask incident on another region of the wafer is of the first illumination type. By selectively regionally controlling illumination type in the photolithography process, resolution of the exposure system is optimized in all regions of the wafer.
26 Citations
55 Claims
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1. A photomask, comprising:
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a substrate having a first region and a second region; and
a polarizing structure formed in the substrate in one of the first and second regions, such that when radiation of a first illumination type impinges on the substrate and the polarizing structure, radiation of a second illumination type is formed in the one of the first and second regions and radiation of a third illumination type is formed in the other of the first and second regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of making a photomask, comprising:
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providing a substrate having a first region and a second region; and
forming a polarizing structure in the substrate in one of the first and second regions, such that when radiation of a first illumination type impinges on the substrate and the polarizing structure, radiation of a second illumination type is formed in the one of the first and second regions and radiation of a third illumination type is formed in the other of the first and second regions. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A photolithography method used in fabricating a circuit, comprising:
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positioning a photomask over a semiconductor substrate on which the circuit is to be formed, the circuit having first and second regions corresponding to first and second regions of the photomask, the photomask having a polarizing structure formed in one of the first and second regions of the photomask; and
illuminating the photomask with radiation of a first illumination type, such that radiation of a second illumination type impinges on the one of the first and second regions of the substrate corresponding to the one of the first and second regions of the photomask, and radiation of a third illumination type impinges on the other of the first and second regions of the substrate. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A photomask, comprising:
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a substrate having a first region and a second region; and
a polarizing structure formed in the substrate in one of the first and second regions;
whereinthe polarizing structure is formed on the surface of a chrome side of the substrate.
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55. A method of making a photomask, comprising:
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providing a substrate having a first region and a second region; and
forming a polarizing structure in the substrate in one of the first and second regions;
whereinthe polarizing structure is formed on the surface of a chrome side of the substrate.
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Specification