Method for creating gray-scale features for dual tone development processes

1. A method of patterning a substrate using a dual-tone development process, comprising:

providing a substrate having a layer of radiation-sensitive material on said substrate, wherein said layer of radiation-sensitive material comprises a dual tone photo-resist;

providing a mask having a dual-tone mask pattern region configured for printing dual-tone features and a half-tone mask pattern region configured for printing half-tone features;

performing a dual-tone development process by performing one or more exposures of said layer of radiation-sensitive material to one or more patterns of radiation to print said dual-tone features in said dual tone photo-resist with a double pattern in said dual-tone mask pattern region and print half-tone features in said dual tone photo-resist without a double pattern in said half-tone mask pattern region; and

selecting mask properties of said half-tone mask pattern region for use with said dual tone photo-resist such that said dual-tone development process avoids producing pattern defects that include an undesirable void in half-tone features printed by said dual-tone development process.

2. The method of claim 1 , wherein said selecting mask properties comprises determining an optimal transmission of said half-tone mask pattern region.

3. The method of claim 1 , wherein said half-tone mask pattern region comprises an opaque region having a plurality of sub-resolution transparent features.

4. The method of claim 3 , wherein said selecting mask properties comprises determining an optimal geometry of said plurality of sub-resolution transparent features as a function of exposure conditions and proximity environments using simulation, or experiment, or both.

5. The method of claim 3 , wherein said selecting mask properties comprises determining an optimal size of each of said plurality of sub-resolution transparent features, or an optimal spacing of each of said plurality of sub-resolution transparent features, or both the optimal size and spacing of said plurality of sub-resolution transparent features.

6. The method of claim 3 , wherein each of said plurality of sub-resolution transparent features comprises any arbitrary shape.

7. The method of claim 1 , wherein said half-tone mask pattern region comprises a sub-resolution grating.

8. The method of claim 7 , wherein said selecting mask properties comprises determining an optimal geometry of said sub-resolution grating as a function of exposure conditions and proximity environments using simulation, or experiment, or both.

9. The method of claim 8 , wherein said selecting mask properties comprises determining an optimal pitch for said sub-resolution grating, an optimal size for said sub-resolution grating, an optimal duty-cycle for said sub-resolution grating, or an optimal mask edge offset for said sub-resolution grating, or any combination of two or more thereof.

10. The method of claim 1 , wherein said dual-tone photo-resist comprises a photo-resist that switches solubility due to a change in polarity upon said exposing to said one or more patterns of radiation and optionally elevating a temperature of said substrate to a first post-exposure temperature, or a second post-exposure temperature, or both following said exposing.

11. The method of claim 1 , wherein said dual-tone photo-resist comprises a photo-resist that provides acid-catalyzed deprotection upon said exposing to said one or more patterns of radiation and optionally elevating a temperature of said substrate to a first post-exposure temperature, or a second post-exposure temperature, or both following said exposing.