Multi-field overlay control in jet and flash imprint lithography
Techniques for delivering sub-5 nm overlay control over multiple fields. One such technique reduces overlay from the wafer side using wafer-thermal actuators. In another technique, the topology of the template is optimized so that the inter-field mechanical coupling between fields in the multi-field template is reduced thereby allowing overlay to be simultaneously reduced in multiple fields in the template. A further technique combines the wafer-thermal and template actuation techniques to achieve significantly improved single and multi-field overlay performance.
1. A template, comprising:
multiple lithography fields for imprinting at multiple locations simultaneously; and
multiple holes machined in unpatterned regions to reduce inter-field mechanical coupling and permit overlay control over said multiple lithography fields simultaneously.
2. The template as recited in claim 1 , wherein said multiple lithography fields are separated by unpatterned regions.
3. The template as recited in claim 1 , wherein imprint material is confined to said multiple lithography fields printed by the use of recessed regions in said unpatterned regions.
4. The template as recited in claim 1 , wherein locations of said holes are determined using an optimization algorithm using a population of optimization parameters.
5. The template as recited in claim 4 , wherein said optimization parameters comprise a template density matrix and correction force locations.
6. The template as recited in claim 1 , wherein locations of said holes are selected based on optimizing overlay errors.
7. The template as recited in claim 1 , wherein said overlay control comprises reducing one of the following errors: translation errors in X and Y, magnification errors in X and Y, orthogonality errors and angular errors.
8. The template as recited in claim 1 , wherein said overlay control comprises reducing higher order errors in overlay.
9. A wafer system, comprising:
a wafer comprising an array of fields, wherein two or more fields of said array of fields are lithography fields for imprinting at multiple locations simultaneously; and
a grid of heating/cooling elements underneath each of said two or more lithography fields causing thermal expansion and contraction resulting in overlay reduction.
10. The wafer system as recited in claim 9 , wherein said overlay reduction comprises reducing one of the following errors: translation errors in X and Y, magnification errors in X and Y, orthogonality errors and angular errors.
11. The wafer system as recited in claim 9 , wherein said overlay reduction comprises reducing higher order errors in overlay.
12. The wafer system as recited in claim 9 , wherein said heating/cooling elements operate on the peltier effect.
13. A system, comprising:
a template comprising:
multiple lithography fields for imprinting at multiple locations simultaneously; and
multiple holes machined in unpatterned regions to reduce inter-field mechanical coupling and permit overlay control over said multiple lithography fields simultaneously; and
a wafer system comprising:
a wafer comprising an array of fields, wherein two or more fields of said array of fields are lithography fields for imprinting at multiple locations simultaneously; and
a grid of heating/cooling elements underneath each of said two or more lithography fields causing thermal expansion and contraction resulting in overlay control;
wherein said overlay control via said multiple holes and said grid of heating/cooling elements control overlay in a coordinated manner.
14. The system as recited in claim 13 , wherein said overlay control comprises reducing one of the following errors: translation errors in X and Y, magnification errors in X and Y, orthogonality errors and angular errors.
15. The system as recited in claim 13 , wherein said overlay control comprises reducing higher order errors in overlay.