Method of replicating a microstructure pattern
A method includes providing a first multilayer structure including a substrate, a thin film, and a first photoresist layer; providing a second multilayer structure including a mold having a microstructure pattern, and a second photoresist layer; combining the first multilayer structure and the second multilayer structure so that the first photoresist layer is in contact with the second photoresist layer; and applying pressure and temperature. An article including a microstructure pattern is also disclosed.
1. A method, comprising:
providing a first multilayer structure including a substrate, a thin film, and a first photoresist layer;
providing a second multilayer structure including a mold having a microstructure pattern, and a second photoresist layer;
combining the first multilayer structure and the second multilayer structure so that the first photoresist layer is in contact with the second photoresist layer; and
applying pressure and temperature to form a photoresist stack, the photoresist stack having a replicated microstructure pattern, and a base portion that does not have the replicated microstructure pattern;
removing the mold;
after removing the mold, applying a flood exposure using a collimated light source to the photoresist stack, wherein collimated light exposes the replicated microstructure pattern and the base portion of the photoresist stack that does not have the replicated microstructure pattern; and
etching the photoresist stack and the thin film to form an etched microstructure pattern from the photoresist stack into the thin film.
2. The method of claim 1 , wherein the second photoresist layer has the replicated microstructure pattern, and the base portion that does not have the replicated microstructure pattern.
3. The method of claim 1 , wherein the thin film is a high refractive index material thin film.
4. The method of claim 1 , wherein the mold having the microstructure pattern is coated with a release agent.
5. The method of claim 1 , wherein the mold is made of a material chosen from metal, semiconductor, dielectric, or combinations thereof.
6. The method of claim 1 , wherein the first photoresist layer and the second photoresist layer are made of the same material or different materials.
7. The method of claim 1 , wherein the photoresist stack does not include air pockets.
8. The method of claim 1 , further comprising, developing the photoresist stack.
9. The method of claim 1 , wherein the step of etching is chosen from a reactive ion etching, an Inductively Coupled Plasma-Reactive Ion Etching process, and an ion milling step.
10. The method of claim 1 , wherein the etched microstructure pattern in the thin film while having an opposite polarity may or may not have a same aspect ratio as the microstructure pattern of the mold;
wherein the replicated microstructure pattern in the photoresist stack while having the opposite polarity is substantially the same as the microstructure pattern of the mold; and
wherein the etched microstructure pattern in the thin film while having a same polarity may or may not have a same aspect ratio as the replicated microstructure pattern in the photoresist stack.
11. The method of claim 1 , wherein prior to forming the second photoresist layer, the second multilayer structure is formed by applying a release coating to the mold; and
exposing the applied release coating to a treatment to render a surface of the release coating hydrophilic.
12. The method of claim 11 , wherein the second photoresist is formed by:
applying a first photoresist sublayer onto the release coating;
heating the first photoresist sublayer; and
after heating the first photoresist sublayer, applying a second photoresist sublayer onto the first photoresist sublayer.
13. The method of claim 12 , wherein the first photoresist sublayer is applied at a thickness ranging from about 1 to about 20 microns.
14. The method of claim 12 , wherein the heating the first photoresist sublayer comprises heating at a temperature ranging from about 50° C. to about 90° C., for a period of time ranging from about 1 second to about 30 minutes.
15. The method of claim 12 , wherein the second photoresist sublayer is applied at a thickness ranging from about 1 to about 20 microns.
16. The method of claim 12 , further comprising after applying the second photoresist sublayer, heating at a temperature ranging from about 50° C. to about 90° C., for a period of time ranging from about 1 second to about 30 minutes.
17. The method of claim 8 , wherein the photoresist stack is a positive tone photoresist.
18. The method of claim 1 , wherein the photoresist stack is a positive tone photoresist.