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US 6,271,911 B1Granted
Apparatus for enhancing image contrast using intensity filtration
AssigneeLSI Logic Corporation
InventorKunal N. Taravade
Life of this patent
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Abstract
A photolithography apparatus for deep UV enhances contrast and also therefore increases the resolution of patterned images by passing only intensities that fall within a specific minimum threshold value, resulting in a more exact aerial image replicating the mask image. this photolithography apparatus employs a different approach to contrast enhancement which is distinguished from previous methods by eliminating the need for an extra layer of contrast enhancement on top of the resist, thereby reducing the number of processing steps in semiconductor fabrication.
Claims9
An apparatus comprising:
- a lens;
- a beam splitter, wherein light passing through the lens is split into a first light beam and a second light beam;
- a filter including:
- an input, wherein light passing thorough the lens is received at the input;
- a linear material having a first refractive index;
- a nonlinear material having a second refractive index, wherein the second refractive index varies from a first intensity of light to a second intensity of light;
- and
- an output,
- wherein the first refractive index substantially matches the second refractive index at the first intensity of light such that light of the first intensity in the first light beam is passed though the filter and wherein the first refractive index and the second refractive index are mismatched at the second intensity of light such that light of the second intensity in the first light beam is blocked from passing through the filter to the output;
- and
- a light guiding apparatus, wherein the light guiding apparatus receives the second light beam and guides the second light beam such that the second light beam merges with the first light beam at the output of the filter, wherein a merged light beam is formed.
8 more elements
Dependencies are inferred from the claim text.