Methods of producing slanted gratings

Patent metadata

Field	Value
Publication number	US-10690821-B1
Application number	US-201916297981-A
Country	US
Kind code	B1
Filing date	Mar 11, 2019
Priority date	Dec 14, 2018
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

Methods of producing gratings with trenches having variable height and width are provided. In one example, a method includes providing an optical grating layer atop a substrate, and providing a patterned hardmask over the optical grating layer. The method may include forming a mask over just a portion of the optical grating layer and the patterned hardmask, and etching a plurality of trenches into the optical grating layer to form an optical grating. After trench formation, at least one of the following grating characteristics varies between one or more trenches of the plurality of trenches: a trench depth and a trench width.

First claim

What is claimed is:

1. A method of forming a diffracted optical element, comprising:
providing an optical grating layer atop a substrate;
providing a patterned hardmask over the optical grating layer;
forming a mask over just a portion of the optical grating layer and the patterned hardmask, wherein the mask is formed directly atop a top surface of the optical grating layer; and
etching a plurality of trenches into the optical grating layer to form an optical grating, wherein a first depth of a first trench of the plurality of trenches is different than a second depth of a second trench of the plurality of trenches.

2. The method of claim 1 , wherein a first width of the first trench of the plurality of trenches is different than a second width of the second trench of the plurality of trenches.

3. The method of claim 1 , further comprising patterning the mask prior to etching the plurality of trenches into the optical grating layer.

4. The method of claim 1 , wherein the etching comprises performing an angled ion etch.

5. The method of claim 4 , wherein the angled ion etch is performed by a reactive ion beam, and wherein the substrate is scanned along a scan direction with respect to the reactive ion beam.

6. The method of claim 1 , further comprising forming the patterned hardmask as a plurality of hardmask elements each separated from one another by a gap, wherein a first subset of the plurality of hardmask elements is adjacent a second subset of the plurality of hardmask elements, wherein each of the first subset of the plurality of hardmask elements has a first width, wherein each of the second subset of the plurality of hardmask elements has a second width, and wherein the first width is greater than the second width.

7. The method of claim 6 , further comprising forming the mask to include two or more heights relative to a top surface of the optical grating layer.

8. The method of claim 6 , further comprising forming the mask over just the second subset of the plurality of hardmask elements.

9. The method of claim 6 , wherein the first width of the first trench of the plurality of trenches is approximately equal to the second width of the second trench of the plurality of trenches.

10. A method of forming an optical grating component, comprising:
providing an optical grating layer atop a substrate;
providing a patterned hardmask over the optical grating layer;
forming a mask over just a portion of the optical grating layer and the patterned hardmask, wherein the mask has a lower etch resistance than the patterned hardmask, and wherein the mask is formed directly atop a top surface of the optical grating layer; and
etching a plurality of trenches into the optical grating layer to form an optical grating, wherein a trench depth varies between one or more trenches of the plurality of trenches.

11. The method of claim 10 , wherein the etching comprises performing an angled ion etch.

12. The method of claim 11 , wherein the angled ion etch is applied to each of: the optical grating layer, the patterned hardmask, and the mask.

13. The method of claim 11 , wherein a first trench of the plurality of trenches formed in the portion of the optical grating layer has a first depth, wherein a second trench of the plurality of trenches formed in a second portion of the optical grating layer has a second depth, and wherein the second depth is greater than the first depth.

14. The method of claim 10 , further comprising patterning the mask prior to etching the plurality of trenches into the optical grating layer.

15. The method of claim 10 , further comprising forming the patterned hardmask as a plurality of hardmask elements each separated from one another by a gap, wherein a first hardmask element of the plurality of the hardmask elements has a different width than a width of a second hardmask element of the plurality of hardmask elements.

16. The method of claim 15 , further comprising forming a first subset of the plurality of hardmask elements adjacent a second subset of the plurality of hardmask elements, wherein each of the first subset of the plurality of hardmask elements has a first width, wherein each of the second subset of the plurality of hardmask elements has a second width, wherein the first width is greater than the second width, wherein each of the plurality of trenches has an approximately uniform width.

17. The method of claim 16 , further comprising forming the mask over just the second subset of the plurality of hardmask elements.

18. A method of forming an optical grating component, comprising:
providing an optical grating layer atop a substrate;
providing a patterned hardmask over the optical grating layer;
forming a mask over just a portion of the optical grating layer and the patterned hardmask, and wherein the mask is formed directly atop a top surface of the optical grating layer; and
forming a plurality of trenches in the optical grating layer by etching the optical grating layer, the patterned hardmask, and the mask, wherein at least one of the following grating characteristics varies between one or more trenches of the plurality of trenches: a trench depth and a trench width.

19. The method of claim 18 , further comprising:
forming a first trench of the plurality of trenches in the portion of the optical grating layer to a first depth; and
forming a second trench of the plurality of trenches in a second portion of the optical grating layer to a second depth, wherein the second depth is greater than the first depth.

20. The method of claim 18 , further comprising forming the patterned hardmask as a plurality of hardmask elements each separated from one another by a gap, wherein a first hardmask element of the plurality of the hardmask elements has a different width than a width of a second hardmask element of the plurality of hardmask elements.

Assignees

• Applied Materials Inc

Inventors

• Evans Morgan
• Meyer Timmerman Thijssen Rutger
• Clark Megan

Classifications

• H10P50/282

  of inorganic materials · CPC title

• H10P50/267

  using plasmas · CPC title

• H10P50/242

  of Group IV materials · CPC title

• H10P14/69215

  the material being a silicon oxide, e.g. SiO2 · CPC title

• G02B5/1847 Primary

  Manufacturing methods · CPC title