Optical element having metallic seed layer and aluminum layer, and method for producing same

Patent metadata

Field	Value
Publication number	US-11466356-B2
Application number	US-202016994526-A
Country	US
Kind code	B2
Filing date	Aug 14, 2020
Priority date	Aug 16, 2019
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

A method for producing an aluminum layer is provided. The method includes depositing a metallic seed layer on a substrate, the seed layer having a thickness of not more than 5 nm, and also includes applying the aluminum layer to the seed layer, wherein the aluminum layer has a thickness of more than 30 nm. Further, an optical element, which can be a mirror layer, is provided including the metallic seed layer and the aluminum layer.

First claim

The invention claimed is:

1. A method for producing an optical element including a substrate, a metallic seed layer on the substrate and an aluminum layer deposited on a side of the metallic seed layer that faces away from the substrate, wherein the aluminum layer directly adjoins the metallic seed layer and the aluminum layer has a root mean square roughness of less than 0.7 nm, the method comprising:
depositing the metallic seed layer on the substrate, the metallic seed layer having a thickness of not more than 5 nm; and
applying the aluminum layer directly to the metallic seed layer, wherein the aluminum layer has a thickness of 30 nm to 100 nm inclusive.

2. The method according to claim 1 , wherein the metallic seed layer comprises Cu, Ti, Fe, Zn or Cr.

3. The method according to claim 1 , wherein the metallic seed layer is between 2 nm and 5 nm thick.

4. The method according to claim 1 , wherein the metallic seed layer is between 2.5 nm and 3.5 nm thick.

5. The method according to claim 1 , wherein the aluminum layer has a root mean square surface roughness of less than 0.4 nm.

6. The method according to claim 1 , further comprising applying a protective layer to the aluminum layer, wherein the protective layer has a thickness of not more than 5 nm.

7. An optical element comprising:
a substrate;
a metallic seed layer on the substrate, the metallic seed layer having a thickness of not more than 5 nm; and
an aluminum layer disposed on a side of the metallic seed layer that faces away from the substrate,
wherein the aluminum layer directly adjoins the metallic seed layer,
wherein the aluminum layer has a thickness of 30 nm to 100 nm inclusive, and
wherein the aluminum layer has a root mean square roughness of less than 0.7 nm.

8. The optical element according to claim 7 , wherein the metallic seed layer comprises Cu, Ti, Fe, Zn or Cr.

9. The optical element according to claim 7 , wherein the optical element is a mirror, and wherein the aluminum layer is a mirror layer.

10. The optical element according to claim 7 , wherein the metallic seed layer is between 2 nm and 5 nm thick.

11. The optical element according to claim 7 , wherein the metallic seed layer is between 2.5 nm and 3.5 nm thick.

12. The optical element according to claim 7 , wherein the aluminum layer has a root mean square surface roughness of less than 0.4 nm.

13. The optical element according to claim 7 , further comprising a protective layer disposed on the aluminum layer, wherein the protective layer has a thickness of not more than 5 nm.

14. An optical element comprising:
a substrate;
a metallic seed layer on the substrate, the metallic seed layer having a thickness of not more than 5 nm; and
an aluminum layer disposed on a side of the metallic seed layer that faces away from the substrate,
wherein the aluminum layer directly adjoins the metallic seed layer,
wherein the aluminum layer has a thickness of more than 30 nm,
wherein the metallic seed layer is between 2.5 nm and 3.5 nm thick, and
wherein all layers of the optical element are arranged on a same side of the substrate.

15. The optical element of claim 14 , wherein the metallic seed layer comprises Cu, Ti, Fe, Zn or Cr.

16. The optical element of claim 14 , wherein the optical element is a mirror, and wherein the aluminum layer is a mirror layer.

17. The optical element of claim 14 , further comprising a protective layer disposed on the aluminum layer, wherein the protective layer has a thickness of not more than 5 nm.

18. The optical element of claim 14 , wherein the aluminum layer has a root mean square surface roughness of less than 0.4 nm.

Assignees

• Fraunhofer Ges Forschung
• Univ Jena Friedrich Schiller

Inventors

• Stempfhuber Sven
• Gäbler Dieter
• Schmitt Paul
• Munzert Peter
• Schwinde Stefan

Classifications

• G02B5/0808 Primary

  having a single reflecting layer (G02B5/0883, G02B5/0891 take precedence) · CPC title

• C23C14/025 Primary

  Metallic sublayers · CPC title

• G02B5/0891

  Ultraviolet [UV] mirrors (apparatus for microlithography exposure G03F7/70; X-ray multilayer structures G21K1/06) · CPC title

• C23C14/14

  Metallic material, boron or silicon · CPC title

• C23C14/021

  Cleaning or etching treatments · CPC title