Mask for improving lithography performance by using multi-transmittance photomask
AssigneeMacronix International Co., Ltd.
InventorChih-Cheng Yang
Life of this patent
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Abstract
Materials and methods for fabricating multi-transmittance halftone phase shift masks (HTPSM) are disclosed. The masks include patterns having regions of different transmittance for the purpose of reducing one or more of line edge shortening, iso-to-dense bias, and edge-to-dense bias. The masks employ at least one halftone material in forming the patterns that have different transmittances. Regions of denser or longer lines are constructed to have a lower transmittance than regions of isolated lines. The patterns may include a single halftone material of different thicknesses for different regions or may include two halftone materials applied singly and doubly to different regions.
Claims20
A mask, having transparent areas forming spaces and partially transparent areas forming objects, the mask comprising:
- a transparent substrate having a full transmittance and having spaces defined thereon with the same full transmittance and with the same phase-shift value;
- a first pattern of objects having a first partial transmittance and a first phase-shift value, formed on the transparent substrate;
- and
- a second pattern of objects having a second partial transmittance and a second phase-shift value equal to the first phase-shift value, formed on the transparent substrate, wherein the second pattern is longer or denser than the first pattern, and the first partial transmittance is higher than the second partial transmittance.
A photomask, comprising:
- a first pattern of objects having a first partial transmittance and a phase-shift value:
- a second pattern of objects having a second partial transmittance and the same phase-shift value, the second pattern being longer or denser than the first pattern and the first transmittance being higher than the second transmittance;
- and
- spaces disposed between the objects of the first pattern and the second pattern the spaces having full transmittances and the same phase-shift value.
Dependencies are inferred from the claim text.