Liquid masks for microfabrication processes
Disclosed herein are methods of using a fluoro oil mask to prepare a beam pen lithography pen array.
1. A method of making a beam pen lithography tip array, comprising
providing a tip array comprising a plurality of tips fixed to a common substrate, the common substrate fixed to a support, the plurality of tips and common substrate each comprising an at least translucent material, each tip having a radius of curvature of less than 1 μm, the tip array further comprising a coated surface comprising a blocking layer, the coated surface disposed over the plurality of tips;
casting a mask material onto the tip array to form a mask over the tip array that provides an exposed portion of each tip of the tip array, wherein the mask material and the blocking layer interact via capillary action to form the mask over the tip array and provide substantially uniform exposed portions of each tip, and
forming an aperture at the exposed portion of each tip by removing the blocking layer at the exposed portion of each tip.
2. The method of claim 1 , wherein the thickness of the common substrate is 50 μm to 100 μm, the common substrate and tips have a combined thickness of less than 200 μm, or both.
3. The method of claim 1 , wherein the blocking layer comprises a metal, a metal oxide, a polymer, a composite, a ceramic, or a combination thereof.
4. The method of claim 1 , wherein the blocking layer comprises a metal.
5. The method of claim 1 , wherein the blocking layer comprises a self-assembled monolayer (SAM) on a metal.
6. The method of claim 1 , wherein the mask material comprises an oil or polymer.
7. The method of claim 6 , wherein the mask material comprises a thermoplastic, or comprises poly(methyl methacrylate) (PMMA) or polypropylene (PP).
8. The method of claim 1 , wherein the mask material is a liquid and the casting comprises spin coating the liquid onto the tip array or the mask material is a solid and the casting comprises melting the solid to a liquid or semi-solid form before and during application to the tip array.
9. The method of claim 1 , wherein the mask material is a solid and the casting comprises melting the solid to a liquid or semi-solid form before and during application to the tip array.
10. The method of claim 1 , wherein the mask material comprises a fluoro oil.
11. The method of claim 1 , wherein the blocking layer comprises a SAM-modified metal and the mask material comprises an oil, and optionally wherein the metal of the SAM-modified metal comprises Au, Ag, Pt, or Cu.
12. The method of claim 1 , wherein the blocking layer comprises gold and the mask material comprises a thermoplastic, and optionally wherein the thermoplastic comprises PMMA.
13. The method of claim 1 , wherein the blocking layer comprises gold having a perfluroinated alkane thiol SAM and the mask material comprises a perfluorinated oil.
14. The method of claim 1 , wherein the casting comprises spin coating, drop casting, spray coating, or film coating.
15. The method of claim 1 , wherein the at least translucent material comprises a polymer.
16. The method of claim 15 , wherein the at least translucent material comprises a crosslinked polymer or a polymer gel.
17. The method of claim 1 , wherein the tip material is elastomeric, reversibly deformable, and/or substantially transparent.
18. The method of claim 1 , wherein the tip material comprises polydimethylsiloxane (PDMS) or trimethylsiloxy terminated vinylmethylsiloxane-dimethysiloxane copolymer, a methylhydrosiloxane-dimethylsiloxane copolymer, or a mixture thereof.
19. The method of claim 1 , wherein the aperture has a diameter of 30 nm to 20 μm.
20. A method for sub-micron scale printing of indicia on a photosensitive substrate, comprising:
orienting the photosensitive substrate near or in contact with a tip array prepared by the method of claim 1 , wherein the photosensitive substrate and the tip array are within 1 μm of each other;
irradiating at least one tip of the tip array with a radiation source, to transmit radiation through the tip aperture; and
exposing a portion of the photosensitive substrate with the transmitted radiation to print the indicia on the substrate surface.