Patterning device, a method of making the same, and a patterning device design method
A patterning device, includes: an absorber layer on a patterning device substrate; and a reflective or transmissive layer on the patterning device substrate, wherein the absorber layer and the reflective or transmissive layer together define a pattern layout having a main feature and an attenuated sub-resolution assist feature paired with the main feature, wherein: the main feature is configured to generate, upon transferring the device pattern to a layer of patterning material on a substrate, the main feature in the layer of patterning material, and upon the transferring the pattern to the layer of patterning material, the attenuated sub-resolution assist feature is configured to avoid generating a feature in the layer of patterning material and to produce a different radiation intensity than the main feature.
1. A method of making a patterning device, the method comprising:
removing, from an absorber layer over a patterning device substrate of the patterning device, a portion of absorber material to form a first set of pattern layout features and a second set of pattern layout features;
providing a masking material on at least part of the second set of pattern layout features so as to expose the first set of pattern layout features while covering the second set of pattern layout features; and
removing at least of part of the absorbing layer for the first set of pattern layout features while the second set of pattern layout features are covered by the masking material.
2. The method of claim 1 , wherein the first set of mask features includes a main feature of a device pattern layout and wherein the removing comprises exposing a reflective or transmissive surface of the patterning device substrate.
3. The method of claim 2 , wherein the second set of mask features includes a sub-resolution assist feature and the sub-resolution feature has a non-zero thickness of absorbing material.
4. The method of claim 1 , wherein the patterning device corresponds to a dark field patterning device.
5. The method of claim 1 , wherein the first set of mask features includes a sub-resolution assist feature.
6. The method of claim 5 , wherein the first set of mask features protrude from the patterning device substrate and the removing comprises reducing a height or thickness of the first set of mask features.
7. The method of claim 5 , wherein the patterning device corresponds to a bright field patterning device.
8. The method of claim 1 , wherein the patterning device is reflective and configured to reflect extreme ultraviolet radiation.
9. A computer program product comprising a non-transitory computer-readable medium having instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to perform the method of claim 1 .
10. A method of making a patterning device, the method comprising:
removing, from an absorber layer over a patterning device substrate of the patterning device, a portion of absorber material to form a set of pattern layout features;
providing a masking material on at least part of the set of pattern layout features so as to expose a portion of the patterning device substrate while covering the set of pattern layout features; and
adding an absorbing material to the exposed portion of the patterning device substrate while the set of pattern layout features are covered by the masking material.
11. The method of claim 10 , wherein the adding comprises physical or chemical vapor deposition.
12. The method of claim 10 , wherein the set of mask features includes a main feature of a device pattern layout and wherein the adding comprises adding an absorbing material to a reflective surface of the patterning device substrate.
13. The method of claim 12 , wherein the exposed portion corresponds to a sub-resolution assist feature of a device pattern layout and the adding comprises forming the sub-resolution feature with a non-zero thickness of absorbing material.
14. The method of claim 10 , wherein the patterning device corresponds to a dark field patterning device.
15. The method of claim 10 , wherein the set of mask features includes a sub-resolution assist feature.
16. The method of claim 15 , wherein the set of mask features protrude from the patterning device substrate and the adding comprises forming a main feature of a device pattern layout.
17. The method of claim 15 , wherein the patterning device corresponds to a bright field patterning device.
18. The method of claim 10 , wherein the patterning device is reflective and configured to reflect extreme ultraviolet radiation.
19. A method, comprising:
obtaining a matching formulation that matches a maximum aerial image intensity of a first diffraction spectrum associated with a patterning device pattern layout having a clear sub-resolution feature (clear SRAF) with a maximum aerial image intensity of a second diffraction spectrum associated with the patterning device pattern layout modified to have an attenuated sub-resolution feature (attenuated SRAF); and
solving, by a hardware computer, the matching formulation to determine a value of a dimension of the attenuated SRAF.
20. The method of claim 19 , further comprising determining an attenuation value and/or absorber thickness for the attenuated SRAF for use in solving the matching formulation.