System and method for verifying and controlling the performance of a maskless lithography tool
First Claim
1. A maskless lithography system, comprising:
- a spatial light modulator that includes a plurality of spatial light modulator cells;
a reference reticle having at least one reference feature, the reference reticle located in a plane with the spatial light modulator proximate to one of the plurality of spatial light modulator cells;
a pattern rasterizer that applies a signal to the spatial light modulator to form a die pattern that includes the at least one reference feature;
an illumination source that emits illumination energy to illuminate the spatial light modulator and the reference reticle;
projection optics, having a pupil, that form a die image with illumination energy entering the pupil from the spatial light modulator and a reference image with illumination energy entering the pupil from the reference reticle; and
a reference reticle postioner that positions the reference reticle to direct incident illumination energy from the illumination source away from the pupil of the projection optics.
1 Assignment
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Accused Products
Abstract
A maskless lithography tool that includes a reference reticle having reference features for tuning and calibrating the tool. The reference reticle is illuminated by a illumination source to form a reference image of the reference features. A signal is applied to an active contrast device of the tool to form a die pattern that includes the reference features. The contrast device is illuminated by the illumination source to form a die image of reference features. An image scanner captures the reference image and the die image. A comparison of the images is used to make tuning and calibrating adjustments to the tool. The reference reticle can be used to debug and characterize the tool even when the operation of the contrast device is not completely understood because the reference features of the reference reticle are independent of the tool'"'"'s contrast device and pattern generating data stream.
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Citations
22 Claims
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1. A maskless lithography system, comprising:
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a spatial light modulator that includes a plurality of spatial light modulator cells; a reference reticle having at least one reference feature, the reference reticle located in a plane with the spatial light modulator proximate to one of the plurality of spatial light modulator cells; a pattern rasterizer that applies a signal to the spatial light modulator to form a die pattern that includes the at least one reference feature; an illumination source that emits illumination energy to illuminate the spatial light modulator and the reference reticle; projection optics, having a pupil, that form a die image with illumination energy entering the pupil from the spatial light modulator and a reference image with illumination energy entering the pupil from the reference reticle; and a reference reticle postioner that positions the reference reticle to direct incident illumination energy from the illumination source away from the pupil of the projection optics. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for adjusting a maskless lithography system that includes an illumination source, a spatial light modulator, a reference reticle having at least one reference feature, and projection optics having a pupil, comprising:
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(a) illuminating the reference reticle with illumination energy emitted by the illumination source; (b) forming a reference image of the at least one reference feature of the reference reticle with illumination energy from the reference reticle that enters the pupil of the projection optics; (c) applying a signal to the spatial light modulator to form a die pattern that includes the at least one reference feature; (d) illuminating the spatial light modulator with illumination energy emitted by the illumination source while the signal is applied to the spatial light modulator; (e) forming a die image of at least one reference feature with illumination energy from the spatial light modulator that enters the pupil of the projection optics; (f) comparing the die image of the at least one reference feature to the reference image of the at least one reference feature; (g) adjusting the maskless lithography system based on the comparison in step (f); and (h) positioning the reference reticle to reflect incident illumination energy from the illumination source away from the pupil of the projection optics. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification