METHOD OF ITERATIVE COMPENSATION FOR NON-LINEAR EFFECTS IN THREE-DIMENSIONAL EXPOSURE OF RESIST
First Claim
1. A method of forming a three-dimensional latent image with good depth and shape control in a layer of resist applied over a workpiece surface, the method including:
- converting a relief map that represents a three-dimensional surface into point-by-point exposure doses calculated to exceed an exposure threshold of the resist at a plurality of controlled depths within the resist layer, producing an exposure map; and
repeating for two or more iterations,simulating the patterning of the resist layer with a pattern generator that varies effective exposure doses on a point-by-point basis using the exposure map to produce a simulated three-dimensional latent image,comparing the simulated three-dimensional latent image to the relief map, andautomatically revising the exposure map using results of the comparing.
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Accused Products
Abstract
The field of this disclosure is making three-dimensional topographic structures by means of graduated exposure in a photosensitive material, such as a photoresist, photosensitive polymide, or similar. Such patterns may be written either to be used directly as optical, mechanical, fluidic, etc. components, e.g. diffusors, non-reflecting surfaces, Fresnel lenses and Fresnel prisms, computer-generated holograms, lenslet arrays, etc, or to be used as masters for the fabrication of such components by replication. Replication can be done by molding, pressing, embossing, electroplating, etching, as known in the art. This disclosure includes descriptions of using passive absorbing components in thin resist, using high gamma thick resists with high resolution pattern generators, using multiple focal planes including at least one focal plane in the bottom half of the resist, and iterative simulation of patterning and adjustment of an exposure map.
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Citations
24 Claims
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1. A method of forming a three-dimensional latent image with good depth and shape control in a layer of resist applied over a workpiece surface, the method including:
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converting a relief map that represents a three-dimensional surface into point-by-point exposure doses calculated to exceed an exposure threshold of the resist at a plurality of controlled depths within the resist layer, producing an exposure map; and repeating for two or more iterations, simulating the patterning of the resist layer with a pattern generator that varies effective exposure doses on a point-by-point basis using the exposure map to produce a simulated three-dimensional latent image, comparing the simulated three-dimensional latent image to the relief map, and automatically revising the exposure map using results of the comparing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification