Method of direct etching fabrication of waveguide combiners

Patent metadata

Field	Value
Publication number	US-11327218-B2
Application number	US-201816762869-A
Country	US
Kind code	B2
Filing date	Nov 13, 2018
Priority date	Nov 29, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

Embodiments described herein relate to methods for fabricating waveguide structures utilizing substrates. The waveguide structures are formed having input coupling regions, waveguide regions, and output coupling regions formed from substrates. The regions are formed by imprinting stamps into resists disposed on hard masks formed on surfaces of the substrates to form positive waveguide patterns. Portions of the positive waveguide patterns and the hard masks formed under the portions are removed. The substrates are masked and etched to form gratings in the input coupling regions and the output coupling regions. Residual portions of the positive waveguide patterns and the hard masks disposed under the residual portions are removed to form waveguide structures having input coupling regions, waveguide regions, and output coupling regions formed from substrates.

First claim

What is claimed is:

1. A method for forming a waveguide structure comprising:
imprinting a stamp into a resist to form a positive waveguide pattern, the resist is disposed on a hard mask formed on a surface of a portion of a substrate, the positive waveguide pattern comprises a pattern including at least one of a first plurality of grating patterns, a waveguide pattern, and a second plurality of grating patterns, each of the first plurality of grating patterns and the second plurality of grating patterns have a residual layer and top pattern surfaces;
performing a curing process to cure the positive waveguide pattern;
releasing the stamp;
performing a first etching process to remove the residual layer and the hard mask disposed under the residual layer and to expose the surface of the substrate;
masking the substrate to expose a first unprotected area of the surface of the substrate;
performing a second etching process for a first period of time to form a first plurality of gratings with first depths;
masking the substrate to expose a second unprotected area of the surface of the substrate;
performing the second etching process for a second period of time to form a second plurality of gratings with second depths are different than that of the first depths; and
removing the top pattern surfaces, the waveguide pattern, and the hard mask disposed under the top pattern surfaces and the waveguide pattern to form a waveguide structure comprising at least one of an input coupling region, a waveguide region, and an output coupling region.

2. The method of claim 1 , wherein the top pattern surfaces and the residual layer are parallel to the surface of the substrate.

3. The method of claim 1 , wherein the first plurality of grating patterns and the second plurality of grating patterns further comprise sidewall pattern surfaces oriented normal to the surface of the substrate.

4. The method of claim 1 , wherein the first plurality of grating patterns and the second plurality of grating patterns further comprise sidewall pattern surfaces slanted by an amount relative to the surface of the substrate.

5. The method of claim 1 , wherein the first etching process comprises:
plasma ashing using at least one of an oxygen gas (O 2 ) containing plasma, a fluorine gas (F 2 ) containing plasma, a chlorine gas (Cl 2 ) containing plasma and a methane (CH 4 ) containing plasma until the residual layer is removed; and
ion etching, reactive ion etching (RIE), or highly selective wet chemical etching the hard mask disposed under the residual layer.

6. The method of claim 1 , wherein the second etching process comprises angled ion etching.

7. The method of claim 6 , wherein the resist is deposited of the surface of the portion of the substrate by a liquid material pour casting process, a spin-on coating process, a liquid spray coating process, a dry powder coating process, a screen printing process, a doctor blading process, a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, a flowable CVD (FCVD) process, or an atomic layer deposition (ALD) process.

8. A method for forming a waveguide structure comprising:
imprinting a stamp into a resist to form a positive waveguide pattern, the resist is disposed on a hard mask formed on a surface of a portion of a substrate, the positive waveguide pattern comprises a pattern including at least one of a first plurality of grating patterns, a waveguide pattern, and a second plurality of grating patterns, each of the first plurality of grating patterns and the second plurality of grating patterns have a residual layer, top pattern surfaces, and sidewall pattern surfaces slanted relative to the surface of the substrate;
performing a curing process to cure the positive waveguide pattern;
releasing the stamp;
performing a first etching process to remove the residual layer and the hard mask disposed under the residual layer and to expose the surface of the substrate;
masking the substrate to expose a first unprotected area of the surface of the substrate;
etching at an angle for a first period of time to form a first plurality of angled gratings with first depths;
masking the substrate to expose a second unprotected area of the surface of the substrate;
etching at the angle for a second period of time to form a second plurality of angled gratings with second depths are different than that of the first depths; and
removing the top pattern surfaces, the waveguide pattern, and the hard mask disposed under the top pattern surfaces and the waveguide pattern to form a waveguide structure comprising at least one of an input coupling region, a waveguide region, and an output coupling region.

9. The method of claim 8 , further comprising:
masking the substrate to expose a third unprotected area of the surface of the substrate; and
etching at the angle for a third period of time to form a third plurality of angled gratings with third depths.

10. The method of claim 9 , wherein each of the first plurality of angled gratings with the first depths, second plurality of angled gratings with the second depths, and third plurality of angled gratings with the third depths include:
top surfaces parallel to the surface of the substrate;
sidewall surfaces slanted by an amount relative to the surface of the substrate; and
bottom surfaces corresponding to the surface of the substrate.

11. The method of claim 10 , wherein etching at the angle comprises directional reactive ion etching (RIE).

12. The method of claim 8 , wherein the first etching process comprises:
plasma ashing using at least one of an oxygen gas (O 2 ) containing plasma, a fluorine gas (F 2 ) containing plasma, a chlorine gas (Cl 2 ) containing plasma and a methane (CH 4 ) containing plasma until the residual layer is removed; and
ion etching, reactive ion etching (RIE), or highly selective wet chemical etching the hard mask disposed under the residual layer.

13. The method of claim 8 , wherein the curing process comprises ultraviolet (UV) curing, infrared (IR) curing, solvent evaporation curing, or thermal curing.

14. The method of claim 8 , wherein the resist is deposited of the surface of the portion of the substrate by a liquid material pour casting process, a spin-on coating process, a liquid spray coating process, a dry powder coating process, a screen printing process, a doctor blading process, a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, a flowable CVD (FCVD) process, or an atomic layer deposition (ALD) process.

15. A method for forming a waveguide structure comprising:
imprinting a stamp into a resist to form a positive waveguide pattern, the resist is disposed on a hard mask formed on a surface of a substrate, the positive waveguide pattern comprises a pattern including at least one of a first plurality of grating patterns, a waveguide pattern, and a second plurality of grating patterns, each of the first plurality of grating patterns and the second plurality of grating patterns have a residual layer, top pattern surfaces, and sidewall pattern surfaces slanted by relative to the surface of the substrate;
electromagnetic radiation curing the positive waveguide pattern;
releasing the stamp;
plasma ashing until the residual layer is removed;
reactive ion etching the hard mask disposed under the residual layer to expose the surface of the substrate;
masking the substrate to expose a first unprotected area of the surface of the substrate;
directional reactive ion etching (RIE) at an angle for a first period of time to form a first plurality of angled gra

Assignees

• Applied Materials Inc

Inventors

• Young Michael Yu-Tak
• Mcmillan Wayne
• Meyer Timmerman Thijssen Rutger
• Visser Robert Jan

Classifications

• H10P50/242

  of Group IV materials · CPC title

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title

• G03F7/0005 Primary

  Production of optical devices or components in so far as characterised by the lithographic processes or materials used therefor · CPC title

• G03F7/0002 Primary

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

• G02B6/0038

  Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide · CPC title