Nano-imprint lithography method involving substrate pressing
View Patent ↗The inventive method includes a preparation step during which the substrate is covered with a layer, a pressing step in which a mould including a pattern of recesses and protrusions is pressed into part of the thickness of the aforementioned layer, at least one etching step in which the layer is etched until parts of the surface of the substrate have been stripped, and a substrate etching step whereby the substrate is etched using an etching pattern which is defined from the mould pattern. The preparation step includes a sub-step consisting of the formation of a lower sub-layer of curable material, a step involving the curing of said layer and a sub-step including the formation of an outer sub-layer which is adjacent to the cured sub-layer. Moreover, during the pressing step, the above-mentioned protrusions in the mould penetrate the outer sub-layer until contact is reached with the cured sub-layer.
1. A lithographic method comprising the pressing of a substrate, the method comprising:
preparing a substrate surface by forming a composite layer on the substrate, wherein forming the composite layer comprises forming an internal sub-layer of curable material in contact with the substrate surface and curing the internal sub-layer, and forming an external sub-layer adjacent to the cured internal sub-layer;
pressing a mold comprising a pattern of recesses and protrusions, wherein the protrusions of the mold penetrate into the external sub-layer until the protrusions contact the internal sub-layer;
performing at least one etching process in which the composite layer is etched by removing the internal sub-layer in regions defined by recesses formed in the external sub-layer until portions of a surface of the substrate have been exposed; and
etching portions of the substrate exposed by the recesses using an etching pattern defined by the mold pattern.
2. The method according to claim 1 , wherein forming the internal sub-layer and the external sub-layer comprise forming the same material.
3. The method according to claim 1 , wherein curing the internal sub-layer comprises heating the internal sub-layer at a temperature higher than a curing temperature of the internal sub-layer, and wherein pressing the mold comprises pressing at a pressing temperature higher than a glass transition temperature of the external sub-layer.
4. The method according to claim 1 , wherein forming the internal sub-layer of a curable material comprises forming a polymer.
5. The method according to claim 1 , wherein forming the internal sub-layer of a curable material comprises forming a resin configured to be cross-linked.
6. The method according to claim 4 , wherein forming the internal sub-layer of a curable material comprises forming one of a negative resin or a positive resin.
7. The method according to claim 1 , wherein forming the internal sub-layer comprises forming a sub-layer having a thickness of 0.01 micron to 1 micron.
8. The method according to claim 1 , wherein forming the external sub-layer comprises forming the external sub-layer to a thickness less than a depth of the pattern of recesses.
9. The method according to claim 5 , wherein forming a resin comprises forming one of a negative resin or a positive resin.
10. A lithographic method comprising:
forming a first layer in contact with a surface of a substrate, the first layer comprising a curable material, and curing the first layer;
forming a second layer on the first layer, the second layer comprising a deformable material;
pressing a mold against the second layer, wherein protrusions of the mold form recesses in the second layer that expose portions of the first layer;
etching the exposed portions of the first layer using the second layer as an etch mask, and exposing surface regions of the substrate; and
etching the surface regions of the substrate using at least the first layer as an etching mask.
11. The method according to claim 10 , wherein forming a first layer and a second layer comprise forming the same material.