Systems and methods for roll-to-roll patterning
Systems and methods are disclosed by which patterns of various materials can be formed on flexible substrates by a continuous roll-to-roll manufacturing process. The patterns may include metallic, transparent conductive, or non-metallic elements with lateral dimensions including in the range from below 100 nanometers to millimeters and with thickness dimensions including the range from tens of Angstroms to greater than 10,000 Angstroms. The substrate may be any material capable of sufficient flexibility for compatibility with roll-based processing equipment, including polymeric films, metallic foils, and thin glass, with polymeric films representing a particularly broad field of application. Methods may include the continuous roll-to-roll formation of a temporary polymeric structure with selected areas open to the underlying substrate, the continuous addition or subtraction of constituent materials, and the continuous removal, where necessary, of the polymeric structure and any excess material.
1. A continuous roll-to-roll method for making patterns on flexible substrates of desired lengths, the method comprising:
using a rotary pattern tool having an embossing surface with embossments in a roll-to-roll embossing process, wherein the rotary pattern tool includes a cylinder and wherein the embossments are disposed on an outer radial surface of the cylinder and present a relief pattern complimentary to a first desired relief pattern for a mask layer;
presenting a mask layer to the embossments, wherein the mask layer contacts the embossments;
forming apertures in the mask layer, wherein the apertures correspond to the first desired pattern;
after forming the mask layer, using the mask layer as a patterning mask in a roll-to-roll process;
forming a material layer with a second desired pattern on a flexible substrate based on the first desired pattern of the mask layer; and
continuously removing the mask layer by a roll-to-roll process to expose the second desired pattern on the substrate.
2. The method of claim 1 , wherein forming a material layer with a desired pattern on a flexible substrate includes opening a polymer pattern by chemical or plasma etching or solvent removal.
3. The method of claim 2 , wherein the polymer removal rate is substantially greater than that of the underlying material layer or substrate removal rate.
4. The method of claim 2 , wherein forming a material layer with a desired pattern on a flexible substrate includes depositing a material layer over the substrate with substantially lower etch rate to act as an etch stop.
5. The method of claim 4 , wherein depositing a material layer includes depositing multiple material layers, any one of which may act as the etch stop.
6. The method of claim 1 , wherein forming a material layer with a desired pattern on a flexible substrate includes creating a pattern by adding material to the substrate.
7. The method of claim 1 , wherein forming a material layer with a desired pattern on a flexible substrate includes creating a pattern by selectively removing material from the material layer on the substrate.
8. The method of claim 7 , wherein forming a material layer with a desired pattern on a flexible substrate includes creating a pattern by selectively removing material from the material layer on the substrate through openings in a mask layer.
9. The method of claim 7 , wherein removing material includes chemical, solvent, or plasma etching or electroetching.
10. The method of claim 7 , wherein forming a material layer with a desired pattern on a flexible substrate includes forming a material layer with a desired pattern includes selective removal of material from one or more material layers through openings in pattern layer, followed by addition of one or more materials through openings in the pattern layer.
11. The method of claim 7 , wherein forming a material layer with a desired pattern on a flexible substrate includes forming an essentially planar material surface wherein the thickness of the added material(s) is essentially the same as the thickness of the removed material(s).
12. The method of claim 11 , wherein the one of the patterns formed is conductive and the other is non-conductive.
13. The method of claim 7 , wherein after removal of residual material the patterned polymer layer itself constitutes the desired pattern.
14. The method of claim 7 , wherein after removal of residual material the patterned polymer layer contains additives and is used as a cavity to hold additional material in contact with a lower material or substrate layer.
15. The method of claim 7 , wherein removing material on the substrate includes peeling off a mask pattern after use to form material pattern on the flexible substrate.
16. The method of claim 15 , wherein the polymer mask is removed after use by bonding to a strip sheet, followed by delamination.
17. The method of claim 16 , wherein the polymer mask is removed after use by bonding to a strip sheet followed by delamination using adhesives.
18. The method of claim 1 , wherein using a rotary pattern tool in a roll-to-roll process to form a structured polymeric layer, wherein the structured polymer layer includes a top surface and lower cavity areas, includes coating said polymer on a template surface, wherein the polymer only wets the top surface and not the lower cavity areas.