Methods of forming patterned reticles
The invention includes methods of forming patterned reticles. Design features can be introduced into a layout for a reticle prior to optical proximity correction, and then removed prior to taping a pattern onto the reticle. Design features can alternatively, or additionally, be introduced after optical proximity correction and asymmetrically relative to one or more parts of a reticle pattern. The introduced features can subsequently be taped to the reticle as part of the formation of the patterned reticle.
1. A method of forming a patterned reticle, comprising:
providing a design which is ultimately to be printed in radiation-sensitive material utilizing the patterned reticle, the design having at least two features which are at different locations but otherwise desired to be identical in printed dimension to one another;
utilizing a first set of design rules to develop an approximation of a pattern layout for the patterned reticle, the approximation comprising a first set of layout elements, the layout elements within the approximation for the at least two features being identical to one another;
adding additional layout elements to the approximation to form an adjusted approximation of the pattern layout, the additional layout elements being asymmetric relative to the at least two features so that the layout elements within the adjusted approximation for the at least two features are not identical to one another;
performing an optical proximity correction on the adjusted approximation of the pattern layout to form a pattern layout dataset; and
utilizing the pattern layout dataset either directly or with modification to tape an arrangement of relatively opaque and relatively transparent regions onto a reticle to form the patterned reticle; the patterned reticle ultimately producing the at least two features of the design more similar to each other than it would if the additional layout elements had not been present during the optical proximity correction.
2. The method of claim 1 wherein the pattern layout dataset is utilized directly to tape the arrangement onto the reticle.
3. The method of claim 1 wherein the pattern layout dataset is utilized with modification to tape the arrangement of relatively opaque and relatively transparent regions onto the reticle; and wherein the modification includes addition of one or more elements which will influence a pattern of radiation generated by the radiation passing through a portion of the arrangement of relatively opaque and relatively transparent regions derived from the optical proximity corrected adjusted approximation.
4. The method of claim 1 wherein one of the at least two features is ultimately to be printed to extend through a thicker region of the radiation-sensitive material than another of the at least two features; and wherein the adjustment to the approximation adjusts for an additional thickness of radiation-sensitive material that said one of the features will extend through.
5. The method of claim 1 wherein a location in the radiation-sensitive material printed with one of the at least two features is expected to have a different attribute than a location in the radiation-sensitive material printed with another of the at least two features; and wherein the adjustment to the approximation adjusts for the expected different attribute.
6. The method of claim 1 wherein the radiation ultimately passing through the patterned reticle is expected to have an aberration; and wherein the adjustment to the approximation adjusts for the expected aberration.
7. The method of claim 1 wherein the radiation ultimately passing through the patterned reticle will have astigmatism; and wherein the adjustment to the approximation adjusts for the astigmatism.
8. The method of claim 1 wherein the radiation ultimately passing through the patterned reticle will have varying focal points; and wherein the adjustment to the approximation adjusts for the varying focal points.
9. The method of claim 1 wherein the additional layout elements remain in the plan dataset as the plan dataset is utilized to tape the arrangement of relatively opaque and relatively transparent regions onto the reticle.
10. The method of claim 9 wherein the taped additional layout elements are identical to the additional layout elements that had been added to the approximation.
11. The method of claim 9 wherein the taped additional layout elements correspond to optically corrected versions of the additional layout elements that had been added to the approximation.
12. The method of claim 1 further comprising removing the additional layout elements prior to utilizing the plan dataset to tape the arrangement of reletively opaque and relatively transparent regions onto the reticle.
13. The method of claim 12 wherein the removed additional layout elements are identical to the additional layout elements that had been added to the approximation.
14. The method of claim 12 wherein the removed additional layout elements correspond to optically corrected versions of the additional layout elements that had been added to the approximation.