Nanoimprint lithography material with switchable mechanical properties
A method is described for utilizing NIL materials with switchable mechanical properties. The method comprises applying an imprint mask to a nano-imprint lithography (NIL) material layer. The NIL material layer is comprised of a NIL material with a modulus level below a flexibility threshold. The NIL material layer has an internal property, that when changed, causes a change in the modulus level of the NIL material. The method further comprises detaching the imprinted NIL material layer from the imprint mask, with the low modulus level of the NIL material causing a shape of the imprinted NIL material layer to remain unchanged after detachment. A modulus level of the NIL material is increased by changing an internal property of the NIL material, with the modulus level increased beyond a strength threshold to create a first imprint layer that has a structure that remains unaffected by a subsequent process.
1. A method, comprising:
providing a nano-imprint lithography (NIL) material comprising a first functional group curable via a first curing process and a second functional group curable via a second curing process, the NIL material having an initial modulus level;
applying an imprint mask to a layer of the NIL material to form an imprinted layer, the imprinted layer formed with a pattern;
partially curing the NIL material in the imprinted layer by performing the first curing process to cure the first functional group of the NIL material while the imprint mask is applied to the imprinted layer, wherein the initial modulus level of the NIL material increases to a first modulus level after the first curing process;
detaching the imprinted layer from the imprint mask, the first modulus level of the NIL material causing the pattern of the imprinted layer to remain unchanged after detachment; and
after the imprinted layer is detached from the imprint mask, fully curing the NIL material in the imprinted layer by performing the second curing process to cure the second functional group of the NIL material and to form a fully cured imprinted layer, wherein the first modulus level of the NIL material increases to a second modulus level after the second curing process, wherein the second curing process yields orthogonal cross linking of the first functional group and the second functional group in the NIL material, wherein the fully cured imprinted layer has the pattern, and wherein the pattern is an inverse of a pattern of the imprint mask.
2. The method of claim 1 , wherein the first curing process is an ultraviolet (UV) light curing process, and wherein the second curing process is a thermal curing process.
3. The method of claim 1 , wherein the first functional group is one of acrylates, methacrylates, epoxides, vinyl ethers, and thiols in combination with alkene groups.
4. The method of claim 1 , wherein the second functional group is one of acrylates, methacrylates, epoxides, vinyl ethers, thiols in combination with alkene groups, photodimerizing groups including one of cinnamates and coumarin, and thermally dimerizing groups including one of Diels-Alder adducts and cyclopentadiene-alkyne group.
5. The method of claim 1 , wherein the pattern of the imprint mask is a three-dimensional slanted pattern.
6. The method of claim 1 , further comprising:
over-coating, annealing, etching, or plasma processing the fully cured imprinted layer.