Cylindrical master mold and method of fabrication
Aspects of the present disclosure describe cylindrical molds that may be used to produce cylindrical masks for use in lithography. A structured porous layer may be deposited on an interior surface of a cylinder. A radiation-sensitive material may be deposited over the porous layer in order to fill pores formed in the layer. The radiation-sensitive material in the pores may be cured by exposing the cylinder with a light source. The uncured resist and porous layer may be removed, leaving behind posts on the cylinder's interior surface. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
1. A method for forming a master mold for a cylindrical lithography mask, comprising:
forming a structured porous layer over an interior surface of a cylinder, wherein the cylinder is transparent to optical radiation;
filling one or more pores in the structured porous layer with a filling material;
removing portions of the filling material that are not in one of the one or more pores; and
forming one or more protrusions from the filling material in the one or more pores, wherein the protrusions are formed by using the one or more pores as guide for growth, wherein a length of the protrusions extends beyond the structured porous layer, wherein the one or more protrusions protrude inward from the interior surface of the cylinder towards an interior of the cylinder.
2. The method of claim 1 , wherein the filling material is a radiation-sensitive material.
3. The method of claim 2 , wherein the step of removing the portions of the filling material that are not in one of the one or more pores comprises:
exposing an outside surface of the cylinder with radiation for a sufficient length of time to cure the radiation-sensitive material that is in the one or more pores of the structured porous layer; and
developing the radiation-sensitive material with a developer configured to remove portions of the radiation-sensitive material that have not been cured.
4. The method of claim 3 , wherein the radiation-sensitive material further comprises silicon.
5. The method of claim 4 further comprising:
annealing the cured radiation-sensitive material.
6. The method of claim 2 , wherein forming the one or more protrusions comprises etching away at least a portion of the structured porous layer.
7. The method of claim 1 , wherein the interior surface of the cylinder is an epitaxial seed layer.
8. The method of claim 7 , wherein the filling material is an epitaxial growth of the epitaxial seed layer.
9. The method of claim 8 , wherein the epitaxial seed layer is a semiconductor material.
10. The method of claim 9 , wherein each of the one or more protrusions is configured to act as a light emitting diode (LED), whereby there are one or more LEDs.
11. The method of claim 10 , wherein each of the one or more LEDs are configured to selectively and individually emit light.
12. The method of claim 8 , wherein allowing the filling material in the one or more pores to form one or more protrusions that extend lengthwise beyond the structured porous layer comprises growing the epitaxial growth beyond a thickness of the structured porous layer.
13. The method of claim 1 , wherein the one or more protrusions have a feature size between 1 nanometer and 100 microns.
14. The method of claim 1 , wherein the one or more protrusions have a feature size between 10 nanometers and 1 micron.
15. The method of claim 1 , wherein the one or more protrusions have a feature size between 50 nanometers and 500 nanometers.