# US 2018/0095201 A1 · Fabricating non-uniform diffraction gratings > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0095201 A1 - Document ID: US20180095201A1 - Status: Published application - Kind: A1 - Application number: 15/723,851 - Filed: 2017-10-03 - Published: 2018-04-05 - Earliest claimed: 2016-10-05 - Assignees: Magic Leap, Inc. - Applicants: Magic Leap, Inc. - Inventors: Mauro Melli; Christophe Peroz - Web page: https://patentgrep.com/patent/US20180095201A1 ## CPC - G02B 5/1857: {using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams} - G02B 6/124: Geodesic lenses or integrated gratings - G02B 6/136: by etching - G02B 27/0172: {characterised by optical features} - G02B 27/4205: {having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant} - G02B 27/4272: {having plural diffractive elements positioned sequentially along the optical path} - H01J 37/3056: {for microworking, e. g. etching of gratings or trimming of electrical components} - H01J 37/3171: {for ion implantation} - G02B 2006/12188: {Ion implantation} - G02B 2027/0125: {Field-of-view increase by wavefront division} - H01J 2237/31708: unpatterned - H01J 2237/31711: using mask - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A method of fabricating non-uniform gratings includes implanting different densities of ions into corresponding areas of a substrate, patterning, e.g., by lithography, a resist layer on the substrate, etching the substrate with the patterned resist layer, and then removing the resist layer from the substrate, leaving the substrate with at least one grating having non-uniform characteristics associated with the different densities of ions implanted in the areas. The method can further include using the substrate having the grating as a mold to fabricate a corresponding grating having corresponding non-uniform characteristics, e.g., by nanoimprint lithography. ## Claims ### Claim 1 A method of fabricating non-uniform structures, the method comprising: implanting different densities of ions into corresponding areas of a substrate; patterning a resist layer on the substrate; and then etching the substrate with the patterned resist layer, leaving the substrate with at least one non-uniform structure having non-uniform characteristics associated with the different densities of ions implanted in the areas. ### Claim 2 (depends on 1) The method of claim 1, further comprising: removing the resist layer from the substrate. ### Claim 3 (depends on 2) The method of claim 2, further comprising: fabricating, by nanoimprint lithography, a corresponding non-uniform structure using the substrate having the non-uniform structure as a mold. ### Claim 4 (depends on 2) The method of claim 2, wherein the non-uniform structure comprises a non-uniform grating. ### Claim 5 (depends on 4) The method of claim 4, wherein the grating comprises a binary grating with non-uniform depths corresponding to the different densities of ions. ### Claim 6 (depends on 4) The method of claim 4, wherein the grating comprises a blazed grating with non-uniform depths corresponding to the different densities of ions. ### Claim 7 (depends on 1) The method of claim 1, wherein implanting different densities of ions into corresponding areas of a substrate comprises: implanting first densities of ions into at least one target area along a first direction; and implanting second densities of ions into the target area along a second, different direction, wherein an angle between the first direction and second direction is larger than 0 degree and less than 180 degree. ### Claim 8 (depends on 1) The method of claim 1, wherein implanting different densities of ions into corresponding areas of the substrate comprises: moving a shutter between an ion source and the substrate along a direction, wherein the implanted areas having the different densities of ions are along the direction. ### Claim 9 (depends on 8) The method of claim 8, wherein the shutter is moved according to an ion exposure profile corresponding to the different densities. ### Claim 10 (depends on 8) The method of claim 8, wherein the shutter is a solid panel configured to block ions from passing through. ### Claim 11 (depends on 8) The method of claim 8, wherein the shutter defines a plurality of through-holes allowing ions to propagate from the ion source to the substrate. ### Claim 12 (depends on 11) The method of claim 11, wherein moving the shutter comprises: moving the shutter across a first spot over a first target area in the substrate with a first speed to allow ions pass through the through-holes onto the first target area; moving the shutter from the first spot to a second, sequential spot with a second speed, the second, sequential spot being over a second target area in the substrate, the second speed being faster than the first speed; and moving the shutter across the second, sequential spot with the first speed to allow ions pass through the through-holes onto the second target area. ### Claim 13 (depends on 11) The method of claim 11, wherein moving the shutter comprises: moving the shutter to a first spot over a first target area in the substrate; stopping the shutter at the first spot for a period of time to allow an amount of ions pass through the through-holes onto the first target area; and then moving the shutter to a second, sequential spot over a second target area in the substrate. ### Claim 14 (depends on 1) The method of claim 1, wherein implanting different densities of ions into corresponding areas of the substrate comprises: placing a shutter between an ion source and the substrate, the shutter comprising a plurality of portions with different ion transmittances. ### Claim 15 (depends on 14) The method of claim 14, wherein the plurality of portions comprise a plurality of membranes with different thicknesses corresponding to the different ion transmittances. ### Claim 16 (depends on 1) The method of claim 1, wherein implanting different densities of ions into corresponding areas of the substrate comprises: using a focused ion beam to locally implant the different densities of ions into the corresponding areas of the substrate. ### Claim 17 (depends on 1) The method of claim 1, wherein the resist layer comprises photoresist, and wherein patterning the resist layer on the substrate comprises: depositing a photoresist layer on the substrate including in the areas; exposing the photoresist layer with patterned light using photolithography; and etching one of the exposed photoresist layer and unexposed photoresist of the deposited photoresist layer to develop the patterned resist layer on the substrate. ### Claim 18 (depends on 1) The method of claim 1, wherein etching the substrate comprises using reactive-ion etching. ### Claim 19 (depends on 1) The method of claim 1, wherein areas without ion implantation have a first etch sensitivity and areas with ion implantation have a second etch sensitivity, and wherein a ratio between the first etch sensitivity and the second etch sensitivity is more than 2. ### Claim 20 (depends on 1) The method of claim 1, wherein the substrate is a silicon substrate, and the ions comprise Gallium ions. ### Claim 21 (depends on 1) The method of claim 1, wherein the non-uniform structure has a lateral resolution of no more than 5000 nm. ### Claim 22 (depends on 1) The method of claim 1, wherein the non-uniform structure has an overall size of at least 1 mm. ### Claim 23 (depends on 1) The method of claim 1, wherein implanting different densities of ions into corresponding areas of the substrate comprises: implanting first different densities of ions into first areas of the substrate along a first direction; and implanting second different densities of ions into second areas of the substrate along a second direction, the second areas being adjacent to the first areas in the substrate. ### Claim 24 (depends on 23) The method of claim 23, further comprising removing the resist layer from the substrate leaves the substrate with: a first grating in the first areas, the first grating having increasing diffraction efficiencies along the first direction; and a second grating in the second areas, the second grating having increasing diffraction efficiencies along the second direction. ### Claim 25 (depends on 23) The method of claim 23, wherein implanting different densities of ions into corresponding areas of the substrate comprises: implanting third different densities of ions into the first areas along a third direction different from the first direction, wherein an angle between the first direction and the third direction is larger than 0 degree and less than 180 degree, and wherein the third different densities of ions are smaller than the first different densities of ions. ### Claim 26 (depends on 23) The method of claim 23, wherein implanting different densities of ions into corresponding areas of the substrate comprises: implanting fourth different densities of ions into the second areas along a fourth direction different from the second direction, wherein an angle between the second direction and the fourth direction is larger than 0 degree and less than 180 degree, and wherein the fourth different densities of ions are smaller than the second different densities of ions. ### Claim 27 A device comprising: a diffraction optical element (DOE) having one or more layers on a substrate, each layer including an orthogonal pupil expansion (OPE) diffraction element and an exit pupil expansion (EPE) diffraction element, wherein the OPE diffraction element comprises a first non-uniform grating configured to deflect part of input light beams propagating in the substrate into the EPE diffraction element in the substrate, and wherein the EPE diffraction element comprises a second non-uniform grating configured to deflect part of the deflected light beams from the OPE diffraction element out of the substrate. ### Claim 28 (depends on 27) The device of claim 27, wherein the first non-uniform grating has a first characteristic that varies along a first direction, and the second non-uniform grating has a second characteristic that varies along a second direction to the first direction, and wherein the first non-uniform grating has increasing diffraction efficiencies along the first direction, and the second non-uniform grating has increasing diffraction efficiencies along the second direction. ### Claim 29 (depends on 28) The device of claim 28, wherein an angle between the first direction and the second direction is between 45 degree and 90 degree. ### Claim 30 (depends on 28) The device of claim 28, wherein the first non-uniform grating has a third characteristic that varies along a third direction different from the first direction, and wherein an angle between the first direction and the third direction is larger than 0 degree and less than 180 degree. ### Claim 31 (depends on 28) The device of claim 28, wherein the second non-uniform grating has a fourth characteristic that varies along a fourth direction different from the second direction, and wherein an angle between the second direction and the fourth direction is larger than 0 degree and less than 180 degree. ### Claim 32 (depends on 27) The device of claim 27, further comprising an in-coupling element (ICO) integrated in the substrate and configured to receive the input light beams from outside of the substrate and transmit the input light beams to the DOE in the substrate.