GRATINGS WITH VARIABLE DEPTHS FORMED USING PLANARIZATION FOR WAVEGUIDE DISPLAYS

• US 20190324202A1
• Filed: 04/23/2018
• Published: 10/24/2019
• Est. Priority Date: 04/23/2018
• Status: Active Grant

• Current Assignee: META Platforms Technologies LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Original Assignee: Facebook Technologies, LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Inventors: Colburn, Matthew E., Calafiore, Giuseppe, Leibovici, Matthieu Charles Raoul, Mohanty, Nihar Ranjan
• Granted Patent: US 10,732,351 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 2006/12107 Grating
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/1809 with pitch less than or comparable to the wavelength
• CPC Class Codes: G02B 5/1857 using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
• CPC Class Codes: G02B 5/1866 Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: H01J 2237/08 Ion sources
• CPC Class Codes: H01J 2237/0812 Ionized cluster beam [ICB] sources
• CPC Class Codes: H01J 37/3056 for microworking, e.g. etching of gratings, trimming of electrical components trimming of resistors H01C17/22
• CPC Class Codes: H01L 21/0274 Photolithographic processes
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]

Abstract

A manufacturing system performs a deposition of an etch-compatible film over a substrate. The etch-compatible film includes a first surface and a second surface opposite to the first surface. The manufacturing system performs a partial removal of the etch-compatible film to create a surface profile on the first surface with a plurality of depths relative to the substrate. The manufacturing system performs a deposition of a second material over the profile created in the etch-compatible film. The manufacturing system performs a planarization of the second material to obtain a plurality of etch heights of the second material in accordance with the plurality of depths in the profile created in the etch-compatible film. The manufacturing system performs a lithographic patterning of a photoresist deposited over the planarized second material to obtain the plurality of etch heights and one or more duty cycles in the second material.

Claims

1. A method comprising:

performing a deposition of an etch-compatible film over a substrate, the etch-compatible film comprising a first surface and a second surface opposite to the first surface;

performing a partial removal of the etch-compatible film to create a surface profile on the first surface with a plurality of different depths relative to the substrate;

performing a deposition of a second material over the profile created in the etch-compatible film;

performing a planarization of the second material to obtain a plurality of different etch heights of the second material in accordance with the plurality of different depths in the profile created in the etch-compatible film; and

performing a lithographic patterning of a photoresist deposited over the planarized second material to obtain the plurality of different etch heights and one or more duty cycles in the second material.

2. The method of claim 1, wherein the partial removal of the etch-compatible film is based on an etching of the etch-compatible film at one or more locations on the first surface to create the surface profile.

3. The method of claim 1, wherein the planarization of the second material is based on a chemical mechanical polishing of the second material, the chemical mechanical polishing achieving a target value of thickness and surface roughness of the second material.

4. The method of claim 1, wherein the etch-compatible film is composed of at least one of:

an epoxy resin, a novolac resin, or some combination thereof.

5. The method of claim 1, wherein the plurality of etch heights is in the range of few hundred nanometers to few microns.

6. The method of claim 1, wherein the one or more duty cycles is in the range of 10 percent to 90 percent.

7. The method of claim 1, wherein the etch-compatible film is partially removed to a target thickness in the range of few hundred nanometers to few microns.

8. A manufacturing system comprising:

a first deposition system configured to perform a deposition of an etch-compatible film over a substrate, the etch-compatible film comprising a first surface and a second surface opposite to the first surface;

a first etching system configured to perform a partial removal of the etch-compatible film to create a surface profile on the first surface with a plurality of different depths relative to the substrate;

a second deposition system configured to perform a deposition of a second material over the profile created in the etch-compatible film;

a second etching system configured to perform a planarization of the second material to obtain a plurality of different etch heights of the second material in accordance with the plurality of different depths in the profile created in the etch-compatible film; and

a patterning system configured to perform a lithographic patterning of a photoresist deposited over the planarized second material to obtain the plurality of different etch heights and one or more duty cycles in the second material.

9. The manufacturing system of claim 8, wherein the first etching system is configured to perform the partial removal of the etch-compatible film based on an etching of the etch-compatible film at one or more locations on the first surface to create the surface profile.

10. The manufacturing system of claim 8, wherein the second etching system is configured to perform the planarization of the second material based on a chemical mechanical polishing of the second material, the chemical mechanical polishing achieving a target value of thickness and surface roughness of the second material.

11. The manufacturing system of claim 8, wherein the etch-compatible film is composed of at least one of:

an epoxy resin, a novolac resin, or some combination thereof.

12. The manufacturing system of claim 8, wherein the plurality of etch heights is in the range of few hundred nanometers to few microns.

13. The manufacturing system of claim 8, wherein the one or more duty cycles is in the range of 10 percent to 90 percent.

14. The manufacturing system of claim 8, wherein the etch-compatible film is partially removed to a target thickness in the range of few hundred nanometers to few microns.

15. An optical grating formed by a process comprising the steps of:

performing a deposition of an etch-compatible film over a substrate, the etch-compatible film comprising a first surface and a second surface opposite to the first surface;

performing a partial removal of the etch-compatible film to create a surface profile on the first surface with a plurality of different depths relative to the substrate;

performing a deposition of a second material over the profile created in the etch-compatible film;

performing a planarization of the second material to obtain a plurality of different etch heights of the second material in accordance with the plurality of different depths in the profile created in the etch-compatible film; and

performing a lithographic patterning of a photoresist deposited over the planarized second material to obtain the plurality of different etch heights and one or more duty cycles in the second material.

16. The optical grating of claim 15, wherein the partial removal of the etch-compatible film is based on an etching of the etch-compatible film at one or more locations on the first surface to create the surface profile.

17. The optical grating of claim 15, wherein the planarization of the second material is based on a chemical mechanical polishing of the second material, the chemical mechanical polishing achieving a target value of thickness and surface roughness of the second material.

18. The optical grating of claim 15, wherein the etch-compatible film is composed of at least one of:

an epoxy resin, a novolac resin, or some combination thereof.

19. The optical grating of claim 15, wherein the plurality of etch heights is in the range of few hundred nanometers to few microns.

20. The optical grating of claim 15, wherein the one or more duty cycles is in the range of 10 percent to 90 percent.