Large area nanopatterning method and apparatus
Embodiments of the invention relate to methods and apparatus useful in the nanopatterning of large area substrates, where a rotatable mask is used to image a radiation-sensitive material. Typically the rotatable mask comprises a cylinder. The nanopatterning technique makes use of Near-Field photolithography, where the mask used to pattern the substrate is in contact or close proximity with the substrate. The Near-Field photolithography may make use of an elastomeric phase-shifting mask, or may employ surface plasmon technology, where a rotating cylinder surface comprises metal nano holes or nanoparticles.
1. A method of near-field nanolithography comprising:
a) providing a substrate having a radiation-sensitive layer on said substrate surface;
b) providing a rotatable mask having a nanopattern on an exterior surface of said rotatable mask, wherein said nanopattern is formed from a conformable material, which conforms to said radiation-sensitive layer on said substrate surface;
c) contacting said nanopattern with said radiation-sensitive layer on said substrate surface;
d) distributing radiation through said nanopattern, while rotating said rotatable mask over said radiation-sensitive layer, whereby an image having a feature size ranging from less than 1 μm down to about 1 nm is created in said radiation-sensitive layer.
2. A method in accordance with claim 1 , wherein said feature size ranges from about 100 nm down to 10 nm.
3. A method in accordance with claim 1 , wherein said radiation has a wavelength of 436 nm or less.
4. A method in accordance with claim 1 , wherein said nanopattern is a shaped or nanostructured polymeric material.
5. A method in accordance with claim 3 , wherein said rotatable mask is a phase-shifting mask which causes radiation to form an interference pattern in said radiation-sensitive.
6. A method in accordance with claim 3 , wherein said mask employs surface plasmon behavior.
7. A method in accordance with claim 1 , wherein said rotatable mask is a cylinder.
8. A method in accordance with claim 7 , wherein said cylinder has a flexible wall, whereby said cylindrical shape may be deformed upon contact with said substrate surface.
9. A method in accordance with claim 8 , wherein an optically transparent gas is used to fill said cylinder.
10. A method in accordance with claim 3 , wherein said rotatable mask is a transparent cylinder, whereby radiation may be transmitted from a location interior of said cylinder.
11. A method in accordance with claim 10 , wherein said mask is a phase shifting mask which is present as a relief on a surface of said transparent cylinder.
12. A method in accordance with claim 10 , wherein said mask is a phase shifting mask which is present on a layer applied over a surface of said cylinder.
13. A method in accordance with claim 12 , wherein at least one nanopatterned film is applied to an exterior surface of said cylinder, whereby imaged feature dimensions in said radiation-sensitive layer more precisely represent prescribed feature dimensions.
14. A method in accordance with claim 7 , wherein said substrate is moved in a direction toward or away from a contact surface of said rotatable cylinder during distribution of radiation from said contact surface of said cylinder.
15. A method in accordance with claim 7 , wherein said cylinder is rotated on said substrate while said substrate is static.
16. A method in accordance with claim 1 , wherein multiple rotating masks are contacted with a radiation-sensitive layer.
17. A method in accordance with claim 1 , wherein said rotatable mask and said substrate surface are moved independently using a stepper-motor and a motorized substrate translational mechanism, and wherein movement of said rotatable mask and said substrate surface are synchronized with each other, whereby a slip-free contact exposure of said radiation-sensitive layer is achieved.
18. A method in accordance with claim 1 , wherein a liquid is supplied to an interface between said rotatable mask and said substrate surface.