Process margin using discrete assist features
First Claim
1. A method of improving a process margin of a lithographic imaging system, comprising:
- identifying a semi-isolated pattern feature on a mask as a potential limiting factor to a process margin for a lithographic imaging technique;
determining a resolution threshold for the imaging technique; and
placing one or more discretized sub-resolution assist features near the semi-isolated mask feature.
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Abstract
The subject invention provides a system and method for improving the process margin of a lithographic imaging system. The process margin improvement is achieved through the novel placement of discrete assist features and/or the use of forbidden pitches and specific pitch orientations. Novel geometries are utilized, which take advantage of line-end pull back and/or a lack of resolution of pitches perpendicular to an axis of a dipole illumination source. The strategic placement of a series of discrete scatterbar segments on a mask near positions of critical features, such as, for example, contacts, mitigates resist residue that can result from the use of a contiguous scatterbar.
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Citations
20 Claims
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1. A method of improving a process margin of a lithographic imaging system, comprising:
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identifying a semi-isolated pattern feature on a mask as a potential limiting factor to a process margin for a lithographic imaging technique;
determining a resolution threshold for the imaging technique; and
placing one or more discretized sub-resolution assist features near the semi-isolated mask feature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A photomask comprising:
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one or more semi-isolated mask features; and
one or more discretized scatterbars positioned near at least one of the one or more semi-isolated mask features, the discretized scatterbars alter a pitch of the one or more semi-isolated mask features and mitigate photoresist residue after an exposure period. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A system that facilitates improving wafer yield and mitigating resist residue after a photoresist exposure technique, comprising:
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means for identifying a potential yield-limiting pattern feature on a photomask; and
means for generating a plurality of discrete scatterbar segments that are of a sub-resolution size that can be reliably printed on the photomask and cannot be resolved by an exposure source employed to print photomask features on a resist layer on a wafer;
- View Dependent Claims (20)
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Specification