System and method for repeated metal deposition-dewetting steps to form a nano-particle etching mask producing thicker layer of engraved metasurface

Patent metadata

Field	Value
Publication number	US-11294103-B2
Application number	US-202016875337-A
Country	US
Kind code	B2
Filing date	May 15, 2020
Priority date	May 15, 2020
Publication date	Apr 5, 2022
Grant date	Apr 5, 2022

Abstract

A method and system is disclosed for creating an optical component having a spatially controlled refractive index and uniform anti-reflective layer. The method may involve alternately depositing and dewetting two or more thin metal material layers on the substrate to form a mask having a spatially varying nano-particle distribution, and with an increased thickness beyond what could be achieved using a single, thick layer of the same material. The substrate may then be etched, using the mask, to imprint a spatially patterned nanostructure pattern on a surface the substrate in accordance with the mask.

First claim

What is claimed is:

1. A method for creating an optical component having a spatially controlled refractive index, the method comprising:
providing a substrate;
performing a first deposition operation to form a first metal material layer on a surface of the substrate using a first material having a first wetting characteristic relative to the substrate;
performing a first dewetting operation by heating the first metal material layer to create a first layer of a mask having a plurality of nanoparticles with a spatially varying nanoparticle distribution, and with a first height;
performing a second deposition operation to deposit a second metal material layer on the surface of the substrate using a second material having a second wetting characteristic relative to the substrate;
performing a second dewetting operation to dewet the second metal material layer, the second dewetting operation causing the second metal material layer to accumulate on the nanoparticles to form a second layer of the mask, which increases the first height to a second height, and thus an overall thickness of the mask, without changing the spatially varying nanoparticle distribution of the mask; and
after the mask has been increased to the second height, then etching a surface of the substrate using the mask to imprint a spatially patterned nanostructure pattern on a surface of the substrate in accordance with the spatially varying nanoparticle distribution.

2. The method of claim 1 , wherein the first wetting characteristic is different from the second wetting characteristic.

3. The method of claim 1 , wherein the first wetting characteristic is the same as the second wetting characteristic.

4. The method of claim 1 , wherein the first and second materials comprise identical materials.

5. The method of claim 1 , wherein at least one of the first and second materials comprises:
gold; or
aluminum; or
chromium; or
palladium; or
nickel.

6. The method of claim 1 , further comprising after the etching of the surface is performed, then removing the mask from the substrate.

7. The method of claim 1 , wherein the second dewetting operation is achieved by heating of the second metal material layer.

8. The method of claim 1 , wherein the dewetting of the first metal material layer comprises using a laser to achieve dewetting of the first metal material layer to form the mask.

9. The method of claim 1 , wherein overlapping raster scanned passes of an optical light source are used to irradiate the first metal material layer and the second metal material layer, to thereby dewet the first and second metal material layers.

10. The method of claim 1 , wherein the first and second dewetting operations are performed using at least one light emitting diode (LED).

11. The method of claim 1 , wherein the first and second dewetting operations are performed using thermal processing.

12. The method of claim 1 , wherein the etching comprises performing a wet etching process.

13. The method of claim 1 , wherein after the mask has been increased to the second height, an additional plurality of deposition and dewetting operations are performed to further increase an overall height of the mask to a finished height which is greater than the second height, before etching the surface of the substrate using the mask at the finished height.

14. The method of claim 1 , wherein the etching comprises performing a dry etching process to imprint the spatially patterned nanostructure pattern on the surface of the substrate.

15. The method of claim 14 , wherein the dry etching process comprises a reactive ion etching (RIE) process.

16. A method for creating an optical component having a spatially controlled refractive index, the method comprising:
providing a substrate;
performing a first deposition operation to deposit a first material to form a first metal material layer on a surface of the substrate using a first etching ratio characteristic relative to the substrate;
performing a first dewetting operation by heating the first metal material layer to create a first masking layer having a plurality of nanoparticles with a spatially varying nanoparticle distribution, and with a first height;
performing a second deposition operation to form a second metal material layer on the surface of the substrate using a second material;
performing a second dewetting operation to dewet the second metal material layer, the second dewetting operation causing the second metal material layer to accumulate in interstitial spaces between the nanoparticles of the first metal material layer to form a second masking layer, and where the second material has a second etching ratio characteristic relative to the substrate which is different than the first etching ratio characteristic; and
etching a surface of the substrate using the first and second masking layers to imprint a spatially patterned nanostructure pattern on a surface the substrate in accordance with the spatially varying nanoparticle distribution of the first masking layer.

17. The method of claim 16 , wherein the first and second materials have different wetting characteristics relative to the substrate.

18. The method of claim 16 , wherein the dewetting of the first metal material layer comprises using a laser to generate an optical signal to achieve de-wetting of the first metal layer to form the mask, and wherein the laser is raster scanned over the first and second masking layers.

19. The method of claim 16 , wherein the etching comprises performing at least one of:
a dry etching process to imprint the spatially patterned nanostructure pattern on the surface; or
a wet etching process.

20. The method of claim 16 , wherein the etching comprises performing a dry etching process using a reactive ion etching (RIE) operation.

Assignees

• L Livermore Nat Security Llc

Inventors

• Feigenbaum Eyal
• Ray Nathan James
• Yoo Jae Hyuck

Classifications

• G02B1/002 Primary

  made of materials engineered to provide properties not available in nature, e.g. metamaterials · CPC title

• G02B1/12 Primary

  by surface treatment, e.g. by irradiation · CPC title

• G02B5/1857

  using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams · CPC title

• G02B1/11

  Anti-reflection coatings · CPC title

• G03F7/0002

  Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping · CPC title