Nanoimprint lithography process using low surface energy mask
A method is described for creating a modified mask with low surface energies for a nano-imprint lithography (NIL) imprinting process. The method includes applying a master mold to an imprint mask material to create an imprint mask. The method further includes modifying the imprint mask by applying a treatment to the imprint mask to cause a surface energy level of the imprint mask to fall below a sticking threshold. The modified imprint mask is applied to a nano-imprint lithography (NIL) material to create an imprinted NIL material layer. The surface energy level of the imprint mask causes a shape of the imprinted NIL material layer to be remain unchanged when the imprinted NIL material layer is detached from the modified imprint mask.
1. A method, comprising:
applying a master mold to an imprint mask material to create an imprint mask;
forming a graphitized carbon layer on a surface of the imprint mask to cause a surface energy of the modified imprint mask to fall below a sticking threshold by:
applying a plasma treatment to the surface of the imprinted mask, and
after the plasma treatment is applied to the surface of the imprinted mask, exposing the surface of the imprinted mask to ultraviolet (UV) light; and
applying the modified imprint mask to a nano-imprint lithography (NIL) material layer to create an imprinted NIL material layer, the surface energy level of the modified imprint mask causing a shape of the imprinted NIL material layer to remain unchanged when the imprinted NIL material layer is detached from the modified imprint mask.
2. The method of claim 1 , wherein the plasma treatment is an application of a fluorocarbon plasma to the surface of the imprint mask.
3. The method of claim 2 , wherein the fluorocarbon is composed of one of CF 4 , CHF 3 , CH 2 F 2 , CH 3 F, C 4 F 8 , C 4 F 6 , C 2 F 6 , and C 2 F 8 .
4. The method of claim 1 , wherein the UV light is in a wavelength range of 10 nm to 200 nm.
5. The method of claim 1 , wherein the imprinted NIL material layer has a modulus level beyond a strength threshold, the imprinted NIL material layer having a structure that remains unaffected by a subsequent process to form a second imprint layer matching a pattern of the master mold.
6. The method of claim 1 , wherein the surface energy level of the modified imprint mask is less than a surface energy level of the NIL material layer.
7. The method of claim 1 , wherein forming the graphitized carbon layer on the surface of the imprint mask to cause the surface energy of the modified imprint mask to fall below a sticking threshold further comprises:
evacuating gas from a chamber where the imprinted mask is placed before exposing the surface of the imprinted mask to the UV light.
8. The method of claim 1 , further comprising:
measuring the surface energy of the modified imprinted mask; and
determining that the surface energy of the modified imprinted mask is below the sticking threshold before applying the modified imprint mask to the NIL material layer.
9. The method of claim 1 , further comprising:
etching the imprinted NIL material layer to increase prominence of a pattern of the imprinted NIL material layer.
10. The method of claim 1 , further comprising:
inducing cross linkage of polymers of the imprinted mask material to further cause the surface energy of the modified imprint mask to fall below a sticking threshold.