Formation of angled gratings

Abstract

The systems and methods discussed herein can be used to form gratings at various tilt angles across a grating material on a single substrate by determining an ion beam angle and varying the angle of the ion beam between a plurality of ion beam angles to form a plurality of gratings having varying angles and cross-sectional geometries. The substrate can be rotated about a central axis and one or more process parameters, such as a duty cycle of the ion beam, can be regulated to form gratings with depth gradients.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to angled etching tools. More specifically, embodiments described herein provide for forming gratings with different slant angles, depth gradients, and wedge angles using angled etching tools. BACKGROUND

[0002] Augmented reality creates an experience for a user to view the surrounding environment through a display lens of augmented reality glasses or using other HMD devices. Augmented reality devices allow a user to see images of virtual objects that are generated for display and appear as part of the environment. Augmented reality can include sound and haptic inputs, as well as virtual images, graphics, and audio that can enhance or augment a user's environment.

[0003] One challenge in augmented reality device design and manufacturing is the display of virtual images superimposed on the surrounding environment. Augmented waveguide combiners are used to assist in superimposing the images. First, generated light is in-coupled into the augmented waveguide combiner and propagates through the augmented waveguide combiner. Then, the resulting light is out-coupled from the augmented waveguide combiner and superimposed on the surrounding environment. Surface relief gratings are used to couple light into and out of the augmented waveguide combiner. Using conventional designs can not properly control the intensity of the out-coupled light.

[0004] Another challenge is that waveguide combiners can use gratings with different slant angles depending on the properties desired for the augmented reality device. In addition, waveguide combiners can include gratings with different slant angles to properly control the in-coupling and out-coupling of light, and the slant angles can have different angles from the grating vector.

[0005] Therefore, what is needed are improved augmented waveguide combiners and methods of manufacturing gratings and grating masters. SUMMARY

[0006] In one or more embodiments, a method of forming a grating includes etching a hard mask layer to form a plurality of openings, the hard mask layer disposed on a grating material layer, the grating material layer disposed on a substrate; and forming a first grating in the grating material layer through the plurality of openings of the hard mask layer, wherein the first grating has a first shape vector and a first grating vector. The first grating can be formed by determining a first ion beam angle the first ion beam angle a first slant angle and an angle between the first shape vector and the first grating vector a first portion of the grating material layer is positioned in a path of an ion beam, the ion beam being at a first ion beam angle relative to the substrate The substrate is held on a platen. The method also includes regulating one or more process parameters when the ion beam is at the first ion beam angle to form a first plurality of fins of the first grating, the first plurality of fins having the first shape vector, the first grating vector, and the first tilt angle relative to a surface normal of the substrate so that the first plurality of fins are formed at a first tilt angle In some examples, the first grating is further formed by rotating the substrate about a central axis of the platen to a first rotation angle between the ion beam and the first grating vector of the first grating.

[0007] In some embodiments, a method of forming a grating includes etching a first grating material layer to form first features in the first grating material layer, the first grating material layer disposed on a substrate; depositing an etch stop layer in the first features; depositing a second grating material layer on the etch stop layer; and depositing a hard mask layer on the second grating material layer. The method further includes etching the hard mask layer to form a plurality of openings; and forming a first grating in the second grating material layer through the plurality of openings, wherein the first grating has a first shape vector and a first grating vector. The first grating can be formed by determining a first ion beam angle the first ion beam angle relative to a first tilt angle and an angle between the first shape vector and the first grating vector and positioning a first portion of the substrate relative to an ion beam at the first ion beam angle The substrate is held on a platen, and the first ion beam angle is measured relative to a plane parallel to the platen. The method also includes regulating one or more process parameters when the ion beam is at the first ion beam angle and in contact with the first portion of the substrate. In some examples, the process parameters can be or include a duty cycle of the ion beam, a partial scan of the ion beam, a scan speed of the ion beam, a power source used to generate the ion beam, or any combination thereof.

[0008] In other embodiments, a method of forming a grating includes etching a plurality of openings in a hard mask layer, the hard mask layer disposed on a grating material layer and the grating material layer disposed on a substrate; and etching the substrate through the plurality of openings in the hard mask layer to form a first grating in the grating material layer, the first grating including a plurality of fins formed in a recess, wherein the first grating has a first shape vector and a first grating vector. The first grating can be formed by determining a first ion beam angle The first ion beam angle correlating to a first tilt angle and an angle between the first shape vector and the first grating vector and positioning a first portion of the grating material layer relative to the ion beam at the first ion beam angle The ion beam is adjustable relative to a plane parallel to the substrate at an angle ranging from about 15° to about 75°, the substrate being held on a stage. The method further includes rotating the substrate about a central axis of the stage to a first rotation angle between the ion beam and the first grating vector of the first grating when the ion beam is at the first ion beam angle and etching the first grating at a first angle to remove a top portion of the plurality of fins to form a wedge shape, wherein the first shape vector is a wedge shape vector. BRIEF DESCRIPTION OF DRAWINGS

[0009] The above mentioned and other features of the disclosure, and the manner of obtaining and implementing them, will become more apparent and the disclosure itself will be better understood by reference to the following description of exemplary embodiments taken in conjunction with the accompanying drawings. It is to be understood that the following are merely examples of possible implementations and should not be considered as limiting the scope of the present disclosure.

[0010] Figure 1 A perspective front view of an enhanced waveguide combiner in accordance with one or more embodiments described and discussed herein is depicted.

[0011] Figure 2A A side schematic cross-sectional view of an angled etching system in accordance with one or more embodiments described and discussed herein is depicted.

[0012] Figure 2B A side schematic cross-sectional view of an angled etching system in accordance with one or more embodiments described and discussed herein is depicted.

[0013] Figure 3 A schematic perspective view of a portion of a substrate having an angled grating in accordance with one or more embodiments described and discussed herein is depicted.

[0014] Figure 4 is a flow diagram illustrating a method for forming a grating in accordance with one or more embodiments described and discussed herein.

[0015] Figures 5A to 5J illustrates the structure of different intervals produced during the method depicted in Figure 4 in accordance with one or more embodiments described and discussed herein.

[0016] Figure 6 is a flow diagram illustrating another method for forming a grating in accordance with one or more embodiments described and discussed herein.

[0017] Figures 7A to 7G illustrates the structure of different intervals produced during the method depicted in Figure 6 in accordance with one or more embodiments described and discussed herein.

[0018] Figure 8 is a flow diagram illustrating another method for forming a grating in accordance with one or more embodiments described and discussed herein.

[0019] Figures 9A to 9D illustrates the structure of different intervals produced during the method depicted in Figure 8 in accordance with one or more embodiments described and discussed herein.

[0020] Figure 10 is a flow diagram illustrating another method for forming a grating in accordance with one or more embodiments described and discussed herein.

[0021] Figures 11A to 11D illustrates the structure of different intervals produced during the method depicted in Figure 10 in accordance with one or more embodiments described and discussed herein.

[0022] For ease of understanding, the same reference numbers have been used, where possible, to designate identical elements that are common to the various figures. It is contemplated that elements and features of one implementation can be beneficially incorporated into other implementations without further recitation. DETAILED DESCRIPTION

[0023] Virtual reality and augmented reality devices that employ gratings can utilize depth-tailored slanted gratings in which the direction in which the wedge-shaped grating is formed can not be aligned with the grating vector. Using ion beams that can accommodate a range of angles to etch depth-tailored slanted gratings in a target material, gratings with different slant angles and different depth gradients are formed. The tailoring of the grating depth increases the optical uniformity in optical devices such as waveguide combiners.

[0024] Using the systems and methods discussed herein, gratings having depth gradients misaligned with grating vectors are formed by rotating the substrate and by modulating process parameters (e.g., duty cycle of the ion beam), resulting in smooth gradient depth profiles for each orientation relative to the substrate. Waveguide combiners or other optical elements can be formed using the systems and methods discussed herein, and masters for imprinting waveguide combiners or other optical elements can be further formed using the systems and methods discussed herein. Gratings formed as discussed herein can be formed as wedges or exhibit other cross-sectional shapes.

[0025] The gratings discussed herein are patterns formed in a target material layer, the patterns consisting of a plurality of fins separated by a plurality of troughs. The plurality of fins can be formed at a plurality of depths and heights, and can be formed by etching a target material using an angled, adjustable ion beam and by rotating the substrate. The plurality of fins are formed at an angle of inclination relative to the plane of the substrate. The gratings can be formed with cross-sectional geometries having wedge, rectangular, or other polygonal or circular shapes or combinations of shapes. Gratings can be formed and then modified in height and / or critical dimensions. Depending on the implementation, the critical dimensions discussed herein can refer to the fin height, pitch, width, or other dimensions of the grating.

[0026] The grating vector is measured perpendicular to the grating lines, and the grating vector is aligned with the angle of inclination of the fins. The wedge direction (vector) can be measured by the change in depth of the grating of the wedge, e.g., the direction in which the depth of the fins of the wedge grating increases. In one or more examples, the wedge vector is the same as the scan direction of the apparatus in which the substrate is disposed to form the grating. The angle formed between the wedge vector and the grating vector can be used in combination with the angle of inclination of the fins to determine the ion beam angle used to form the grating.

[0027] Figure 1 A perspective front view of an augmented waveguide combiner 100 in accordance with one or more implementations is depicted. It should be understood that the augmented waveguide combiner 100 described below is an example augmented waveguide combiner and that other augmented waveguide combiners can be used in conjunction with or modified to complete aspects of the present disclosure. The augmented waveguide combiner 100 includes an input-coupling region 102 bounded by a first plurality of gratings 108, an intermediate region 104 bounded by a second plurality of gratings 110, and an output-coupling region 106 bounded by a third plurality of gratings 112. The input-coupling region 102 receives incident light beams having intensity from a microdisplay. Each grating of the plurality of gratings 108 splits the incident light beams into a plurality of modes, each incident light beam having a mode.

[0028] Different beam modes react differently to the enhanced waveguide combiner 100. For example, a zeroth order mode (TO) beam is refracted back or lost in the enhanced waveguide combiner 100. In contrast to the TO beam, a positive first order mode (Tl) beam is coupled through the enhanced waveguide combiner 100 to the intermediate region 104, and a negative first order mode (T-1) beam propagates in the enhanced waveguide combiner 100 in the opposite direction of the Tl beam. Ideally, the incident beam is split into a Tl beam with all of the incident beam intensity to direct the virtual image to the intermediate region 104. In one or more embodiments, each grating of the first plurality of gratings 108 is angled to suppress the T-1 beam and the TO beam. The Tl beam experiences total internal reflection (TIR) through the enhanced waveguide combiner 100 until the Tl beam contacts a second plurality of gratings 110 in the intermediate region 104.

[0029] When the Tl beam contacts a grating of the second plurality of gratings 110, the Tl beam is split into a TO beam, a Tl beam, and a T-1 beam. The TO beam is refracted back or lost in the enhanced waveguide combiner 100, the Tl beams experience TIR in the intermediate region 104 until the Tl beams contact another grating of the second plurality of gratings 110, and the T-1 beam is coupled through the enhanced waveguide combiner 100 to the output coupling region 106. The Tl beams that experience TIR in the intermediate region 104 continue to contact the second plurality of gratings 110 until one of the following occurs: (1) the intensity of the Tl beams coupled through the enhanced waveguide combiner 100 to the intermediate region 104 is exhausted, or (2) the remaining Tl beams propagating through the intermediate region 104 reach an end of the intermediate region 104. The second plurality of gratings 110 is adjusted to control the Tl beams coupled through the beam waveguide combiner 100 to the intermediate region 104. Adjusting the second plurality of gratings 110 controls the intensity of the T-1 beams coupled to the output coupling region 106 to regulate the field of view of the virtual image produced by the microdisplay from the perspective of the user, and to increase the angle of view at which the user can view the virtual image.

[0030] In one or more embodiments, the second plurality of gratings 110 can be referred to herein as a wedge, and is defined by the angle of inclination of the fins forming the wedge (discussed below), the first side 114, and the angled second side 116 opposite the first side 114. The angled side 116 includes a first portion 116A and a second portion 116B. The second plurality of gratings 110 is further defined by a curved first end 118, an angled second end defined by a first portion 120A and a second portion 120B. Depending on the embodiment, the curved first end 118 can take on various curvatures. A first angle a is defined by the first portion 116A of the angled side 116 and the second portion 116B of the angled side 116. A second angle β is defined by the second portion 116B and the first portion 120A of the angled second end. A third angle γ can be defined by the first portion 120A and the second portion 120B of the angled second end. A fourth angle δ can be defined by the first side 114 and the second portion 120B of the angled second end. The systems and methods discussed herein form a wedge or other shape in which each fin of the second plurality of gratings 110 has a first end positioned along the angled second side 116 and a second end positioned along the first side 114. Each fin of the second plurality of gratings 110 can be further defined by various geometric features. For example, the first side of the fin can have a ramp (angle) such that each of the fins along the angled second side 116 has a ramp. The second side of each fin can have an undercut such that each of the fins along the first side 114 has an undercut.

[0031] Further in Figure 1 a depth gradient is defined in a direction from the first side 110A to the second side 110B of the plurality of gratings 110. Figure 1 Depth gradients are also illustrated for at least the second plurality of gratings 110 and the third plurality of gratings 112. Each depth gradient can be further defined by a depth gradient in a direction that is a direction of increase or decrease in depth of a fin of a grating or plurality of gratings. In Figure 1 The depth gradients are shown in shading, increasing from the first side 110A to the second side 110B for the second gratings 110, and increasing from the top 112A to the bottom 112B for the third plurality of gratings 112. A grating vector (not shown here) of the second plurality of gratings 110 is measured normal to the second plurality of gratings 110. A wedge angle of the second plurality of gratings 110 can be defined as the angle between the grating vector and the depth gradient. Similarly, a grating vector (not shown here) of the third plurality of gratings 112 is measured normal to the third plurality of gratings 112.

[0032] The T-1 beam coupled into the output coupling region 106 by the enhanced waveguide combiner 100 experiences TIR in the enhanced waveguide combiner 100. The T-1 beam experiences TIR until the T-1 beam contacts a grating of the plurality of gratings 112, where the T-1 beam splits into: (a) a TO beam that either refracts back in the enhanced waveguide combiner 100 or is lost; (b) a T1 beam that experiences TIR in the output coupling region 106 until the T1 beam contacts another grating of the plurality of gratings 112; and (c) the T-1 beam that is coupled out of the enhanced waveguide combiner 100. The T1 beam that experiences TIR in the output coupling region 106 continues to contact gratings of the plurality of gratings 112 until the intensity in the T-1 beam coupled into the output coupling region 106 by the enhanced waveguide combiner 100 is exhausted or the remaining T1 beam propagating through the output coupling region 106 has reached the end of the output coupling region 106. The plurality of gratings 112 must be adjusted to control the T-1 beam coupled into the output coupling region 106 by the enhanced waveguide combiner 100 in order to control the intensity of the T-1 beam coupled out of the enhanced waveguide combiner 100 to further regulate the field of view of the virtual image generated from the microdisplay from the perspective of the user and further increase the angle of view at which the user can view the virtual image.

[0033] Figure 2A A side view schematic cross-sectional view of an angled etching system 200 is depicted in accordance with one or more embodiments, and Figure 2B A side view schematic cross-sectional view of the angled etching system 200 is depicted. To form gratings having a tilt angle, a grating material 212 disposed on a substrate 210 is etched by the angled etching system 200. In one or more embodiments, the grating material 212 is disposed on an etch stop layer 211 disposed on the substrate 210, and a patterned hard mask 213 is disposed on the grating material 212. In one or more embodiments, the tilt angle of each grating is determined by the angle of the angled etching system 200 The refractive index of the grating material 212 is selected with respect to the substrate 210 to control the in-coupling and out-coupling of light and to facilitate the propagation of light through the waveguide combiner. In some embodiments, the grating material 212 includes a material comprising carbon-containing silicon oxide (SiOC), titanium dioxide (Ti02), silicon oxide (e.g., silicon dioxide (Si02)), vanadium (IV) oxide (V02), aluminum oxide (AI2O3), indium tin oxide (ITO), zinc oxide (ZnO), tantalum pentoxide (Ta205), silicon nitride (SiN or Si3N4), titanium nitride (TiN), and / or zirconium dioxide (Zr02). The refractive index of the grating material 212 is between about 1.5 and about 2.65. In yet another embodiment, the patterned hardmask 213 is an opaque hardmask that is removed after the waveguide combiner is formed. For example, the opaque hardmask includes a reflective material such as chromium or silver.

[0034] In some embodiments, the patterned hardmask 213 is a transparent hardmask. In one or more embodiments, the etch stop layer 211 is an opaque etch stop layer that is removed after the waveguide combiner is formed. In some embodiments, the etch stop layer 211 is a transparent etch stop layer. The angled etching system 200 is configured to execute a plurality of instructions, for example, using a controller (not shown), to form the angled gratings discussed herein. The plurality of instructions executed can include a tilt angle, an ion beam angle, a change in ion beam angle between grating formations, a wedge angle, a depth gradient, and / or other aspects of a wedge to be formed from the gratings.

[0035] The angled etching system 200 includes an ion beam chamber 202 that houses an ion beam source 204. The ion beam source is configured to generate an ion beam 216, such as a ribbon beam, a spot beam, or a full substrate size beam. The ion beam chamber 202 is configured to direct the ion beam 216 at an angle a with respect to a surface normal 218 of the substrate 210. The substrate 210 is held on a stage 206 that is coupled to a first actuator 208. The first actuator 208 is configured to move the stage 206 in a scan motion along a y-direction and / or a z-direction. To form a grating having a tilt angle with respect to the surface normal 218, the ion beam source 204 generates the ion beam 216 and the ion beam chamber 202 directs the ion beam 216 at the angle a toward the substrate 210. The first actuator 208 positions the stage 206 so that the ion beam 216 contacts the grating material 212 at the ion beam angle and etches a grating having the tilt angle on a desired portion of the grating material 212. One or more process parameters (e.g., a duty cycle of the ion beam 216) can be regulated to form the plurality of fins of the grating to have varying depths.

[0036] Figure 3 A schematic perspective view of a portion 300 of a substrate 302 is depicted in accordance with one or more embodiments. The ion beam angle is between about 0° and about 90°. The ion beam angle is adjustable, preferably between about 15° and about 75°, as an ion beam angle of about 0° or about 90° can result in a grating 304 having a tilt angle of about 0° or about 90°, respectively, such that the grating 304 is not tilted. Thus, the tilt angle is determined by the relative orientation between the ion beam angle and the rotational position of the substrate. The substrate 302 is rotated about the x-axis 306 of the stage 206 such that there is a rotation angle φ between the grating vector before rotation of the grating 304 and the grating vector after rotation, measured normal to the grating 304. To form a wedge shape as discussed herein, the duty cycle of the ion beam and / or other process parameters can be adjusted to vary the etch depth.

[0037] In one or more examples, the process parameter can be or include a duty cycle of the ion beam, a partial scan of the ion beam, a scan speed of the ion beam, a power source (e.g., voltage) used to generate the ion beam, or any combination of the above. In some examples, the duty cycle is adjusted from about 5% to about 85%, where a 5% duty cycle forms a shallow fin of the grating and an 85% duty cycle forms the fin of the grating to a deeper depth. In other examples, the partial scan of the ion beam, the scan speed of the ion beam, and / or the power source used to generate the ion beam can be independently adjusted to form various depths (e.g., from relatively shallow to relatively deep) of the grating fin. While the formation of gratings having wedge-shaped cross-sections are discussed herein, in other examples, different gratings having varying depth gradients and tilt angles can be formed to form gratings having curved, arcuate, angled, flat, or other cross-sectional profiles that are combinations of various geometries.

[0038] In one or more embodiments, the ion beam angle is aligned with the depth gradient of the grating. The depth gradient discussed above is a measure of the amount of change in depth of the fin across the grating, and the depth gradient is the direction of the change in fin depth. The ion beam angle is determined by the grating angle rotation such that the tilt angle of the fin is determined, where The shape vector is the direction of the change in depth gradient of the grating, e.g., the direction of the increase in depth of the fin. The depth gradient is the change in depth of the fin across the grating. In one or more examples, for a 22.5° tilted grating, where the wedge is offset 45° from the grating vector,

[0039] Figure 4 This is a flowchart illustrating a method 400 for forming a grating according to one or more embodiments. Figures 5A to 5J This describes the structures of the different sections produced during method 400. In method 400, at operation 402, the target stack is fabricated in multiple sub-operations capable of including chemical vapor deposition (CVD). Figure 5A The image shows a target stack formed at operation 402, the target stack including a substrate 502 and a grating material layer 504 formed on the substrate 502. The target stack further includes a hard mask layer 506 formed on the grating material layer 504. The substrate 502 can be formed of a silicon-based material such as SiO2, and the hard mask layer 506 can be formed of a metallic material such as chromium or titanium, or a dielectric material such as silicon carbonitride (SiCN). The grating material layer 504 can include silicon oxycarbide (SiOC), titanium dioxide (TiO2), silicon dioxide (SiO2), vanadium oxide (VO2), aluminum oxide (Al2O3), indium tin oxide (ITO), zinc oxide (ZnO), tantalum pentoxide (Ta2O5), silicon nitride (Si3N4), titanium nitride (TiN), or zirconium dioxide (ZrO2). Figure 5A The stack shown can be fabricated using various sub-operations, including CVD. In one or more examples, the grating material layer 504 is 150 nm to 350 nm thick, and the hard mask layer 506 is about 15 nm to about 70 nm thick.

[0040] At operation 404, a continuous portion of the hard mask layer 506 is removed to form an opening 508 in the hard mask layer 506. Operation 404 can be performed using one or more chemicals in a wet stripping etch operation to form the opening 508. Figure 5B This illustrates the structure obtained by removing the portion of the hard mask layer 506 at operation 404. At operation 406, a portion of the grating material layer 504 is etched (or otherwise removed) to form feature 510. Figure 5C This illustrates the structure obtained due to the formation of feature 510 at operation 406. Operation 406 can be performed using selective area processing (SAP) etching to remove one or more portions of the grating material layer 504. During operation 406, SAP etching can be used to form feature 510, which can include various cross-sections, including but not limited to... Figure 5C The wedge-shaped cross-section of feature 510 shown. For example, although in Figure 5CThe features 510 are wedge-shaped or triangular in this illustration, but in other examples, various polygons or combined shapes can be formed at operation 406 using SAP etching. The features 510 can be referred to as recesses, and are bounded by a first side 510A, a transition surface 510B, and a second side 510C. The second side 510C is opposite the first side 510A, and the transition surface 510B extends between the first side 510A and the second side 510C. The transition surface 510B is formed at an angle 512 relative to the substrate 502. In Figure 5C In examples, the second side 510C is formed to a greater depth than the first side 510A.

[0041] In one or more implementations, the SAP can include a designed number of exposure cycles, where a given exposure cycle involves scanning the process beam along a particular direction, and then rotating the substrate 502 to a new rotational position. In some examples, the SAP etch can include 2 exposure cycles, 4 exposure cycles, 6 exposure cycles, 8 exposure cycles, or more. In some examples, the SAP etch can include different exposure cycles, where the substrate 502 is positioned at different rotational positions, such that each cycle is performed at a different rotational position. Additional aspects of SAP etching are described and discussed in U.S. Patent No. 10,269,663 (col. 4, line 34 - col. 7, line 61) and U.S. Patent No. 10,302,826, which are incorporated by reference herein.

[0042] At operation 408, an etch stop layer 514 is deposited on the features 510. Figure 5D The structure resulting from depositing the etch stop layer 514 at operation 408 is shown. The etch stop layer 514 can be deposited at operation 408 by a CVD process, atomic layer deposition (ALD), or another process that forms a conformal coating on the features 510. The etch stop layer 514 can be formed to a thickness of 15 nm to 50 nm thick. In one or more examples, the etch stop layer 514 is formed at operation 408 from a nitride, such as tantalum nitride. In another example, the etch stop layer 514 is formed at operation 408 from a silicon-based material, such as silicon oxide.

[0043] At operation 410, a second grating material layer 516 is deposited on the etch stop layer 514. The second grating material layer 516 can be deposited using CVD, and formed on the inside of the features 510 and on either side of the features 510, such that material 516A is in excess. Figure 5EThe structure resulting from depositing the second grating material layer 516 at operation 410 is shown. In one or more embodiments, each of the grating material layer 504 and the second grating material layer 516 is formed from at least one of silicon oxycarbide (SiOC), titanium oxide (e.g., titanium dioxide (Ti02)), silicon oxide (e.g., silicon dioxide (Si02)), vanadium (IV) oxide (V02), aluminum oxide (AI2O3), indium tin oxide (ITO), zinc oxide (ZnO), tantalum pentoxide (Ta205), silicon nitride (SiN or Si3N4), titanium nitride (TiN), zirconium dioxide (Zr02), oxynitrides of the above materials, or any combination of the above materials. The hardmask layer 506 is formed from silicon nitride, silicon oxide, a metal-based layer containing titanium or chromium, a dopant of the above materials, an alloy of the above materials, or any combination of the above materials.

[0044] Subsequently, at operation 412, excess material is removed (planarized) from the second grating material layer 516 to form a planarized surface 518. The planarization at operation 412 can be performed using SAP etching. Figure 5F The structure resulting from planarization at operation 412 is shown. At operation 414, a second hardmask layer 520 is deposited on the second grating material layer 516 and etched to form a plurality of openings 522. Figure 5G The structure resulting from depositing the second hardmask layer 520 at operation 414 is shown. The second hardmask layer 520 can be deposited at operation 414 using CVD and etched using deep ultraviolet (DUV) lithography to form the plurality of openings 522 (e.g., a pattern is formed using DUV that is transferred to the hardmask layer 520 by an etching process). In other examples, the second hardmask layer 520 can be patterned using nanoimprint lithography (NIL) to form the plurality of openings 522. In one or more examples of operation 414, the plurality of openings 522 can be formed in a plurality of sub-operations including depositing a photoresist (not shown) on the second hardmask layer 520, performing DUV lithography to pattern the photoresist, and etching the second hardmask layer 520 through the patterned photoresist. The photoresist can then be removed prior to operation 416. The second hardmask layer 520 can be formed from similar materials as discussed above for the material used to form the hardmask layer 506. In one or more examples, the second hardmask layer 520 is formed from a different material than the material of the etch stop layer 514 such that the two materials have different etch selectivities.

[0045] At operation 416, a first grating 524 including a first plurality of fins 526 is formed in the second grating material layer 516 through the plurality of openings 522 in the second hardmask layer 520. Figure 5HThe structure resulting from forming the first grating 524 is shown at operation 416. Operation 416 can be performed by using the angled etching system discussed above in Figures 2A to 2B operation 416 to form the first plurality of fins 526 at a first tilt angle. During operation 416, to form the first grating 524, the first portion of the substrate 502 is positioned at a first ion beam angle relative to the ion beam. Operation 416 includes determining the first ion beam angle of the first grating 524 As discussed above, the equation The first ion beam angle is determined by rotating from the grating angle of the first grating

[0046] The substrate 502 remains on the stage and the first ion beam angle is measured relative to a plane parallel to the stage as discussed above. The substrate 502 is rotated about the central axis of the stage to a first rotation angle between the ion beam and the first grating vector of the first grating 524 when the ion beam is at the first ion beam angle. The ion beam is a ribbon beam at an angle relative to a plane parallel to the stage that can be adjusted from about 15 degrees to about 75 degrees. The first grating 524 has a first plurality of fins 526 such that fins adjacent to the first end 524A of the first grating 524 are formed to a lesser depth than fins adjacent to the second end 524B of the first grating 524. In one or more examples, the first grating has a depth of about 10 nm to about 400 nm and each fin of the plurality of fins 526 has a width that is about 30% to about 70% of the pitch of the plurality of fins 526. The plurality of fins 526 are formed at a first tilt angle as discussed above that can be from about 0 degrees to about 60 degrees. The plurality of fins 526 can be associated with a first depth gradient such that the height increases from the first side 524A to the second side 524B of the grating 524, thereby increasing the depth of the etch. The change in height of the fins 526 along the bottom surface 524C can create a wedge angle 528. The ion beam has one or more process parameters (e.g., duty cycle) that can be regulated to form the first grating 524. For example, the process parameter when the ion beam is at the first ion beam angle and in contact with the first portion of the substrate can be regulated between about 5% to about 85% duty cycle. A shorter regulation time for the process parameter (e.g., 5%) can be used to form fins of lesser depth, such as those at or near the first end 524A of the first grating 524. Similarly, a longer regulation time for the process parameter (e.g., 85%) can be used to form fins with greater relative depth, such as those at or near the second end 524B of the first grating. In one or more implementations, the first ion beam angle used to form the first grating 524 in operation 416 is aligned with the first depth gradient of the first grating 524.

[0047] In one or more embodiments, after the first grating 524 is formed, additional multiple fins can be formed during subsequent iterations of operation 416. In this example, at operation 416, after the first grating is formed, the first ion beam angle is changed to a second ion beam angle that is different from the first ion beam angle. Subsequent iterations of operation 416 include determining a subsequent ion beam angle The subsequent ion beam angle may be different from the first ion beam angle For example, the second ion beam angle for the first grating 524 As discussed above, the second ion beam angle may be determined using the equation A second portion of the substrate is positioned in the path of the ion beam when the ion beam is positioned at the second ion beam angle. When the ion beam is at the second ion beam angle, the substrate is rotated about the central axis of the platen to a second rotation angle between the ion beam and a second grating vector of a second grating. Thus, at operation 416, multiple gratings can be formed on a single substrate at different tilt angles and different depth gradients by changing the ion beam angle and rotating the substrate.

[0048] At operation 418, the second hard mask layer 520 is removed, for example, by using a wet strip etch as discussed above with respect to operation 404. Figure 5I The structure resulting from removing the second hard mask layer 520 at operation 418 is shown. In some embodiments of method 400, at operation 420, a coating 526A is optionally formed on the multiple fins 526 by using an ALD process. In one or more examples, the coating 526A includes one or more layers of oxide. Figure 5J The structure resulting from forming a coating on the multiple fins 526 at operation 420 is shown. In examples in which more than one grating is formed, at operation 420, some or all of the gratings can be provided with a coating on the gratings. In one or more examples, an ALD process can be used at operation 420 to coat the multiple fins 526 with oxide. In some examples, other methods of forming a conformal coating on the multiple fins 526 can be employed. In one or more examples, the multiple fins 526 can be coated at operation 420 to adjust or refine critical dimensions of the multiple fins 526.

[0049] Figure 6 is a flowchart illustrating a method 600 of forming gratings in accordance with one or more embodiments described and discussed herein. Figures 7A to 7G The structure at different intervals during method 600 is shown. Method 600 includes operations 402, 404, and 406, which have been discussed in detail above with respect to Figure 4 Method 400 in FIG. 4. Figure 7AThe structure resulting from operation 402 is illustrated, including substrate 502 and grating material layer 504 and hardmask layer 506. Figure 7B The structure resulting from operation 404 is illustrated, where, as discussed above in method 400, openings 508 are formed in hardmask layer 506 using a wet strip (chemical) etch. Figure 7C The structure resulting from operation 406 is illustrated after a portion of first grating layer 504 is removed to form features 510. Similar to Figure 5C Features 510 can refer to recesses or angled recesses, as illustrated in FIG. 5B, and are bounded by a first side 510A, a second side 510C opposite the first side 510A, and a transition surface 510B extending between the first side 510A and the second side 510C. An angle 512 is formed between the transition surface 510B and the second side 510C. However, in other examples, features 510 can refer to features that are not angled, such as recesses. Figure 6 In method 600, in contrast to method 400 where an etch stop layer and a second grating material layer are deposited after operation 406, a hardmask layer 702 is deposited at operation 602. Hardmask layer 702 can be deposited at operation 602 by using CVD. Figure 7D The structure resulting from the deposition of hardmask layer 702 at operation 602 is illustrated. Hardmask layer 702 can be formed from a material similar to the materials discussed above with respect to hardmask layer 506 and second hardmask layer 520.

[0050] Subsequently, at operation 604, hardmask layer 702 (which can be referred to herein as a second hardmask layer) is etched to form a plurality of openings 704. Figure 7E The structure resulting from the formation of openings in hardmask layer 702 at operation 604 is illustrated. In some examples, during operation 604, hardmask layer 702 is also removed from portions 710 of grating material layer 504. The plurality of openings 704 can be formed in a plurality of sub-operations, including depositing photoresist (not shown) on hardmask layer 702, performing DUV lithography to pattern the photoresist, and etching hardmask layer 702 through the patterned photoresist. The photoresist can then be removed prior to operation 606. In other examples, the plurality of openings 704 can be formed at operation 604 using NIL.

[0051] At operation 606, grating 706 can be formed by using angled etching to include a plurality of fins 708 formed at a tilt angle and at a depth gradient and wedge angle as discussed above. Operation 606 includes determining a first ion beam angle As discussed above, the first ion beam angle determining a first ion beam angle Figure 7F The structure resulting from the formation of grating 706 at operation 606 is illustrated. Grating 706 can be formed in a similar manner as grating 706 in FIG. 5B.Figure 4 The grating 706 formed at operation 606 is formed in a similar manner to one or more of the gratings discussed at operation 416, by using an angled etching system by rotating the substrate 502 and changing the ion beam angle. For example, the grating 706 formed at operation 606 can be formed by angled etching by rotating the substrate 502 about a central axis perpendicular to the substrate and / or a work table on which the substrate is disposed. An ion beam (e.g., a ribbon beam) is positioned at a predetermined angle with respect to the substrate 502, and the ion beam is used to form the plurality of fins 708 to varying depths by modulating the duty cycle of the ion beam. Operation 606 can be repeated in a similar manner to the iterations of operation 416 discussed above to form a plurality of gratings with varying tilt angles, depth gradients, and wedge angles. As discussed above, each ion beam angle At operation 608 of the method 600, one or more portions 710 of the grating material layer 504 are removed from the grating 706 using SAP etching, thereby forming a wedge 712. Figure 7G The resulting wedge 712 of the plurality of fins 708 of the grating 706 formed after the removal of the plurality of portions 710 of the grating material layer 504 at operation 608 is shown. Figure 7G The wedge 712 is further shown with the hard mask layer 702 removed, which can occur at operation 608 or other operations not discussed herein.

[0052] Figure 8 is a flowchart illustrating a method 800 of forming a grating in accordance with one or more embodiments described and discussed herein. Figures 9A to 9D Structures of different intervals produced during the method 800 are illustrated. At operation 802 in the method 800, a substrate is formed that includes a grating material layer 902 using, for example, CVD. Figure 9A The structure resulting from the formation of the grating material layer 902 at operation 802 is illustrated. In particular, Figure 9A The grating material layer 902 is shown, which can be formed to a thickness of from about 200 nm to about 400 nm using CVD from a silicon-based material that is at least one of silicon oxycarbide (SiOC), silicon oxide (e.g., silicon dioxide (Si02)), silicon nitride (SiN or Si3N4), or silicon carbonitride (SiCN). A hard mask layer 904 is formed over the grating material layer 902 and can be formed from a metal or dielectric material, as discussed above with respect to the methods 400 and 600.

[0053] At operation 804, a plurality of openings 906 are formed in the hard mask layer 904. Figure 9BThe structure resulting from the formation of the hard mask layer 904 of operation 804 is shown. At operation 804, the plurality of openings 906 can be formed in a plurality of sub-operations including: depositing photoresist (not shown) on the hard mask layer 904, performing DUV lithography, and etching or NIL to pattern the photoresist, etching the hard mask layer 904 through the patterned photoresist. The photoresist can then be removed prior to operation 806. Figure 9C The structure resulting from the etching of the hard mask layer 904 at operation 804 is shown.

[0054] At operation 806, a grating 908 is formed in the grating material layer 902 from the silicon-based material using an angled etching system as discussed herein. Operation 806 includes determining a first ion beam angle As discussed above, the first ion beam angle The first ion beam angle The grating 908 can be formed as a wedge grating, where the plurality of fins 910 of the grating 908 increase in size from a first end 908A of the grating 908 to a second end 908B of the grating 908. The grating 908 can be formed at operation 806 in a similar manner to the gratings of operations 416 and 606 described above. The duty cycle of the ion beam configured with the adjustable angle is regulated to form each of the plurality of fins 910 to a varying depth, and the substrate having the grating material layer 902 disposed thereon can also be rotated. In contrast to the method 400, an etch stop layer is not used in the method 800. The hard mask layer 904 is removed at operation 808, for example using chemical etching by wet stripping. Figure 9D The structure resulting from the removal of the hard mask layer 904 at operation 808 is shown.

[0055] Figure 10 is a flowchart illustrating a method 1000 of forming a grating in accordance with one or more embodiments described and discussed herein. Figures 11A to 11D The structure of the different intervals produced during the method 1000 is shown. The method 1000 includes operation 402, which is performed in a similar manner to operation 402 of the method 400 Figure 4 Operation 402 of the method 400. Figure 11A The structure resulting from operation 402 in the method 1000 is shown. Figure 11A A grating material layer 504 formed over the substrate 502 and a hard mask layer 506 formed over the grating material layer are shown. At operation 1002, the hard mask layer 506 is opened to form a plurality of openings 1101 in a similar manner to operations 404 and 804 discussed above using DUV lithography and etching or NIL. Figure 11BThe structure resulting from opening the hard mask layer 506 at operation 1002 in method 1000 is shown. This is in contrast to operation 404 in method 400, where a continuous portion of the hard mask layer is removed. Subsequently, in operation 1004 of method 1000, a grating 1104 is formed in the grating material layer 504 using angled etching, as discussed above, by rotating the substrate 502 and modulating the duty cycle of the ion beam. Operation 1004 includes determining a first ion beam angle As discussed above, the first ion beam angle can be determined by using the equation Figure 11C The structure resulting from forming the grating 1104 at operation 1004 in method 1000 is shown. The grating 1104 is formed to have a plurality of fins 1106, a first end 1104A, a second end 1104B, and a bottom 1104C, and is formed to have a rectangular shape, such that the first end 1104A and the second end 1104B are substantially at right angles to the bottom 1104C. At operation 1006, a portion of the fins 1106 is removed using SAP to form a top surface 1108 of the grating 1104, such that the grating 1104 has a wedge-shaped cross-section. This is in contrast to the rectangular shape formed at operation 1004. Further in operation 1006, a plurality of portions 504A (shown in Figure 11C ) of the grating material layer 504 are removed, as is the hard mask layer 1102. Figure 11D The structure resulting from etching the grating 1104 at operation 1006 in method 1000 is shown. The portion of the fins 1106 removed at operation 1006 is removed at a wedge angle a measured with respect to the substrate 502. Operations 1002, 1004, and 1006 can be repeated to form additional gratings in the grating material layer 504 at other tilt angles using different ion beam angles, different substrate rotation angles, and duty cycle modulation, as discussed herein.

[0056] Embodiments of the present disclosure are further directed to any one or more of the following paragraphs 1-29:

[0057] 1. A method of forming a grating, comprising: etching a hard mask layer to form a plurality of openings, the hard mask layer disposed over a grating material layer, the grating material layer disposed on a substrate; forming a first grating in the grating material layer through the plurality of openings of the hard mask layer, wherein the first grating has a first shape vector and a first grating vector, wherein forming the first grating comprises determining a first ion beam angle from the equation wherein is a first tilt angle, It is the angle between the first shape vector and the first grating vector; the first portion of the grating material layer is positioned in the path of the ion beam, the ion beam forming a first ion beam angle relative to the substrate. The substrate is held on the worktable; the substrate is rotated about the central axis of the worktable to a first rotation angle, the first rotation angle being between the ion beam and the first grating vector of the first grating; and when the ion beam is at the first ion beam angle... At the same time, process parameters are adjusted to form a first plurality of fins of a first grating, the first plurality of fins having a first shape vector, a first grating vector, and a first tilt angle relative to the surface normal of the substrate. Thus, the first plurality of fins are tilted at a first angle. form.

[0058] 2. A method of forming a grating, comprising: etching a first grating material layer to form a first feature in the first grating material layer disposed on a substrate; depositing an etch stop layer in the first feature; depositing a second grating material layer on the etch stop layer; depositing a hard mask layer on the second grating material layer; etching the hard mask layer to form a plurality of openings; and forming a first grating in the second grating material layer through the plurality of openings, wherein the first grating has a first shape vector and a first grating vector, wherein forming the first grating comprises: according to the equation Determine the first ion beam angle in It is the first tilt angle. It is the angle between the first shape vector and the first grating vector; relative to the ion beam, the first portion of the substrate is directed at a first ion beam angle. Positioning, the substrate is held on the worktable, and the first ion beam angle It is measured relative to a plane parallel to the stage; when the ion beam is at the first ion beam angle When the substrate is rotated about the central axis of the stage to a first rotation angle between the ion beam and the first grating vector of the first grating; and when the ion beam is at the first ion beam angle Furthermore, when in contact with the first portion of the substrate, the process parameters are adjusted.

[0059] 3. A method of forming a grating, comprising: etching a plurality of openings in a hard mask layer, the hard mask layer being disposed on a grating material layer and the grating material layer being disposed on a substrate; etching the substrate through the plurality of openings in the hard mask layer to form a first grating in the grating material layer, the first grating including a plurality of fins formed in recesses, wherein the first grating has a first shape vector and a first grating vector, wherein forming the first grating includes: according to equation Determine the first ion beam angle in It is the first tilt angle. It is the angle between the first shape vector and the first grating vector; the first portion of the grating material layer is positioned relative to the ion beam at the first ion beam angle. Positioning, wherein the ion beam can be adjusted relative to a plane parallel to the substrate within an angle range of approximately 15° to approximately 75°, the substrate being held on the worktable; and when the ion beam is at the first ion beam angle At that time, the substrate is rotated about the central axis of the stage to a first rotation angle between the ion beam and the first grating vector of the first grating; and the first grating is etched at a first angle to remove the top portion of the plurality of fins to form a wedge shape, wherein the first shape vector is a wedge vector.

[0060] 4. A method of forming a grating, comprising: etching a hard mask layer to form a plurality of openings, the hard mask layer being disposed on a grating material layer, the grating material layer being disposed on a substrate; forming a first grating in the grating material layer through the plurality of openings in the hard mask layer, wherein the first grating has a first shape vector and a first grating vector, wherein forming the first grating comprises: determining a first ion beam angle. The first ion beam angle With the first tilt angle and the angle between the first shape vector and the first grating vector Related; a first portion of the grating material layer is positioned in the path of the ion beam, the ion beam being at the first ion beam angle relative to the substrate. The substrate is held on the worktable; and when the ion beam is at the first ion beam angle At the same time, process parameters are adjusted to form a first plurality of fins of the first grating, the first plurality of fins having a first shape vector, a first grating vector, and a first tilt angle relative to the surface normal of the substrate. Thus, the first plurality of fins are tilted at a first angle. form.

[0061] 5. A method of forming a grating, comprising: etching a first grating material layer to form a first feature in the first grating material layer disposed on a substrate; depositing an etch stop layer in the first feature; depositing a second grating material layer on the etch stop layer; depositing a hard mask layer on the second grating material layer; etching the hard mask layer to form a plurality of openings; and forming a first grating in the second grating material layer through the plurality of openings, wherein the first grating has a first shape vector and a first grating vector, wherein forming the first grating includes: determining a first ion beam angle. The first ion beam angle With the first tilt angle and the angle between the first shape vector and the first grating vector Related; the first portion of the substrate is positioned relative to the ion beam at the first ion beam angle. Positioning, the substrate is held on the worktable, and the first ion beam angle It is measured relative to a plane parallel to the stage; and when the ion beam is at the first ion beam angle Furthermore, when in contact with the first portion of the substrate, the process parameters are adjusted.

[0062] 6. A method of forming a grating, comprising: etching a plurality of openings in a hard mask layer, the hard mask layer being disposed on a grating material layer and the grating material layer being disposed on a substrate; etching the substrate through the plurality of openings in the hard mask layer to form a first grating in the grating material layer, the first grating including a plurality of fins formed in recesses, wherein the first grating has a first shape vector and a first grating vector, wherein forming the first grating includes: determining a first ion beam angle. The first ion beam angle With the first tilt angle and the angle between the first shape vector and the first grating vector Related; the first portion of the grating material layer is positioned relative to the ion beam at a first ion beam angle. Positioning, wherein the ion beam can be adjusted relative to a plane parallel to the substrate within an angle range of approximately 15° to approximately 75°, the substrate being held on the worktable; and when the ion beam is at the first ion beam angle At that time, the substrate is rotated about the central axis of the stage to a first rotation angle between the ion beam and the first grating vector of the first grating; and the first grating is etched at a first angle to remove the top portion of the plurality of fins to form a wedge shape, wherein the first shape vector is a wedge vector.

[0063] 7. The method according to any one of paragraphs 1-6, wherein the first ion beam angle is determined according to equation .

[0064] 8. The method of any of paragraphs 1-7, further comprising rotating the substrate about a central axis of the worktable to a first rotation angle between the ion beam and the first grating vector of the first grating.

[0065] 9. The method of any of paragraphs 1-8, further comprising forming a second grating in the grating material layer, the second grating comprising a second plurality of fins having a second shape vector and a second grating vector, wherein forming the second grating comprises: determining a second ion beam angle the second ion beam angle related to a second tilt angle and an angle between the second shape vector and the second grating vector positioning a second portion of the grating material layer in a second path of the ion beam at the second ion beam angle to form a second grating in the grating material layer; rotating the substrate about a central axis of the worktable such that a second rotation angle is created between the ion beam and the second grating vector of the second grating; and modulating process parameters while the ion beam is at the second ion beam angle to form a second plurality of fins formed at a second tilt angle and having the second shape vector and the second grating vector.

[0066] 10. The method of any of paragraphs 1-9, wherein the second rotation angle is different than the first rotation angle, and wherein the second ion beam angle is determined according to equation .

[0067] 11. The method of any of paragraphs 1-10, wherein the ion beam is a ribbon beam.

[0068] 12. The method of any of paragraphs 1-11, wherein the first ion beam angle is between about 15° and about 75° relative to a plane perpendicular to the substrate.

[0069] 13. The method of any of paragraphs 1-12, further comprising forming a second grating in the grating material layer, the second grating comprising a second plurality of fins having a second shape vector and a second grating vector, wherein forming the second grating comprises: determining a second ion beam angle according to equation wherein is a second tilt angle, is an angle between the second shape vector and the second grating vector; positioning a second portion of the grating material layer in a second path of the ion beam at a second ion beam angle to form a second grating in the grating material layer; rotating the substrate about a central axis of the worktable such that a second rotation angle is created between the ion beam and the second grating vector of the second grating; and when the ion beam is at the second ion beam angle , tuning process parameters to form a second plurality of fins formed at a second tilt angle and having the second shape vector and the second grating vector.

[0070] 14. The method of any of paragraphs 1-13, wherein the second rotation angle is different than the first rotation angle.

[0071] 15. The method of any of paragraphs 1-14, wherein the process parameters include a duty cycle of the ion beam, a partial scan of the ion beam, a scan speed of the ion beam, a power source used to generate the ion beam, or any combination of the foregoing process parameters.

[0072] 16. The method of any of paragraphs 1-15, further comprising, after forming the first grating, removing the hard mask layer.

[0073] 17. The method of any of paragraphs 1-16, wherein the grating material layer includes one or more of: silicon oxycarbide, silicon oxide, silicon carbonitride, silicon nitride, or any combination of the foregoing materials.

[0074] 18. The method of any of paragraphs 1-17, wherein each of the first grating material layer and the second grating material layer includes one or more of: silicon oxycarbide, titanium dioxide, silicon oxide, vanadium oxide, aluminum oxide, indium tin oxide, zinc oxide, tantalum pentoxide, silicon nitride, titanium nitride, or zirconium dioxide.

[0075] 19. The method of any of paragraphs 1-18, wherein the hard mask layer includes silicon oxide, silicon nitride, or a combination of the foregoing materials.

[0076] 20. The method of any of paragraphs 1-19, wherein the first feature comprises a recess and is bounded by a first side, a second side, and a third side, the first side formed to a first depth in the first grating material layer, the second side bounded by a second depth in the first grating material layer, the third side extending between the first side and the second side, the first depth being less than the second depth.

[0077] 21. The method of any of paragraphs 1-20, wherein the first grating comprises a plurality of fins having a first tilt angle with respect to a surface normal of the substrate

[0078] 22. The method of any of paragraphs 1-21, wherein a height of the first plurality of fins decreases according to a first depth gradient from the first side of the recess to the second side of the recess.

[0079] 23. The method of any of paragraphs 1-22, wherein the first ion beam angle is aligned with a first depth gradient of the first grating.

[0080] 24. The method of any of paragraphs 1-23, further comprising: removing the hard mask layer; and coating the first plurality of fins with an oxide layer.

[0081] 25. The method of any of paragraphs 1-24, further comprising: after forming the first grating, changing the first ion beam angle to a second ion beam angle that is different than the first ion beam angle and forming a second grating in the second grating material layer, the second grating comprising a second plurality of fins having a second shape vector and a second grating vector, wherein forming the second grating comprises: determining a second ion beam angle according to the equation where is a second tilt angle, is an angle between the second shape vector and the second grating vector; positioning a second portion of the substrate in a path of the ion beam at the second ion beam angle ; and while the ion beam is at the second ion beam angle , rotating the substrate about a central axis of the worktable to a second rotation angle between the ion beam and the second grating vector of the second grating, wherein the ion beam contacts the second grating material layer at the second ion beam angle , thereby forming the second plurality of fins having the second tilt angle. the second shape vector, and the second grating vector.

[0082] 26. The method of any of paragraphs 1-25, further comprising, after depositing the second grating material layer, planarizing a substrate in which the first grating is formed to remove a portion of the second grating material layer before forming the first grating in the second grating material layer.

[0083] 27. The method of any of paragraphs 1-26, further comprising forming a conformal oxide coating on the plurality of fins.

[0084] 28. The method of any of paragraphs 1-27, further comprising forming a second grating in the grating material layer, the second grating comprising a second plurality of fins, a second shape vector, and a second grating vector, wherein forming the second grating comprises: determining a second ion beam angle according to the equation wherein is a second tilt angle, is an angle between the second shape vector and the second grating vector; positioning a second portion of the substrate in a path of the ion beam at a second ion beam angle such that a second rotation angle is created between the ion beam and a second grating vector of the second grating; and regulating process parameters to form a second plurality of fins having the second shape vector and the second grating vector when the ion beam is at the second ion beam angle and having a second tilt angle with respect to a surface normal of the substrate, wherein the process parameters comprise a duty cycle of the ion beam, a partial scan of the ion beam, a scan speed of the ion beam, a power source used to generate the ion beam, or any combination of the above process parameters.

[0085] 29. An apparatus or system for performing the method of any of paragraphs 1-28.

[0086] Accordingly, using the systems and methods discussed herein, it is possible to fabricate a plurality of gratings for enhancing a waveguide combiner and / or a master for imprinting a grating material. By using the embodiments discussed herein, it is possible to form gratings with varying depth gradients and tilt angles on a single substrate by varying at least an ion beam angle and regulating a duty cycle of the ion beam in combination with rotating the substrate with respect to the ion beam angle.

[0087] While the foregoing is directed to implementations of the present disclosure, other and further implementations may be devised without departing from the basic scope of the present disclosure, and the scope thereof is determined by the claims that follow. All documents described herein are incorporated by reference herein, including any priority documents and / or testing procedures to the extent they are not inconsistent with this document. As is apparent from the foregoing general description and the specific embodiments, while forms of the present disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the present disclosure. Accordingly, it is not intended that the present disclosure be limited, except as by the claims set forth herein. Similarly, for purposes of the United States, the phrase "means for" as used herein is intended to invoke 35 U.S.C. § 112, paragraph 6 and a claim utilizing the phrase should be construed in accordance therewith. Moreover, no limitation to the scope of the disclosure is intended by the use of the term "comprising" or "including," which neither precludes nor depends on the entire absence of the mentioned components or steps, nor does it preclude that under the conditions one or more of the mentioned components or steps are optionally used, and / or that one or more components are equivalent in function to the mentioned components and / or one or more steps are equivalent in function to the mentioned steps.

[0088] Certain embodiments and features have been described using a set of upper value and a set of lower values. It should be understood that unless otherwise indicated, a range including any combination of any two values including the lower value, and also including the upper value, for example, a range having any lower value in combination with any upper value, a range having any lower value in combination with any upper value, a range having any two lower values in combination, and / or a range having any two upper values in combination. Certain lower limits, upper limits, and ranges are presented in one or more claims below.

Claims

1. A method for forming a grating, comprising: A hard mask layer is etched to form multiple openings, the hard mask layer being disposed on a grating material layer, the grating material layer being disposed on a substrate; A first grating is formed in the grating material layer through the plurality of openings in the hard mask layer, wherein the first grating has a first shape vector and a first grating vector, wherein the first shape vector is the direction in which the depth gradient of the first grating changes, and wherein forming the first grating includes: Determine the first ion beam angle The first ion beam angle With the first tilt angle and the angle between the first shape vector and the first grating vector Relatedly, the first ion beam angle It is based on the equation Certain; The first portion of the grating material layer is positioned in the path of the ion beam, the ion beam being at the first ion beam angle relative to the substrate. The substrate is held on the worktable; and When the ion beam is at the first ion beam angle At the same time, process parameters are adjusted to form a first plurality of fins of the first grating, the first plurality of fins having a first shape vector, a first grating vector, and a first tilt angle relative to the surface normal of the substrate. Thus, the first plurality of fins are tilted at the first angle. form.

2. The method of claim 1, wherein the ion beam is a ribbon beam, and the first ion beam angle It is at an angle of 15 to 75 degrees relative to a plane perpendicular to the substrate.

3. The method of claim 1, further comprising: The substrate is rotated about the central axis of the stage to a first rotation angle between the ion beam and the first grating vector of the first grating.

4. The method of claim 3, further comprising: A second grating is formed in the grating material layer. The second grating includes a second plurality of fins having a second shape vector and a second grating vector, wherein the second shape vector is the direction in which the depth gradient of the second grating changes, and wherein forming the second grating includes: Determine the second ion beam angle The second ion beam angle With the second tilt angle and the angle between the second shape vector and the second grating vector Relatedly, the second ion beam angle It is based on the equation Certain; The second portion of the grating material layer is positioned at the second ion beam angle. In the second path of the ion beam, a second grating is formed in the grating material layer; The substrate is rotated about the central axis of the stage, such that a second rotation angle is generated between the ion beam and the second grating vector of the second grating; and When the ion beam is at the second ion beam angle At the same time, the process parameters are adjusted to form the second plurality of fins, the second plurality of fins being at the second tilt angle. It forms and has the second shape vector and the second grating vector.

5. The method of claim 4, wherein the second rotation angle is different from the first rotation angle.

6. The method of claim 1, wherein the process parameters include: The duty cycle of the ion beam, the partial scan of the ion beam, the scan rate of the ion beam, the power supply used to generate the ion beam, or any combination of the above process parameters.

7. The method of claim 1, further comprising: After the first grating is formed, the hard mask layer is removed, and the grating material layer includes one or more of the following: silicon oxycarbonate, silicon oxide, silicon carbonitride, silicon nitride, or any combination of the above materials.

8. A method for forming a grating, comprising: The first grating material layer is etched to form a first feature in the first grating material layer disposed on the substrate; An etch termination layer is deposited in the first feature; A second grating material layer is deposited on the etch stop layer; A hard mask layer is deposited on the second grating material layer; Etch the hard mask layer to form multiple openings; and A first grating is formed in the second grating material layer through the plurality of openings, wherein the first grating has a first shape vector and a first grating vector, wherein the first shape vector is the direction in which the depth gradient of the first grating changes, and wherein forming the first grating includes: Determine the first ion beam angle The first ion beam angle With the first tilt angle and the angle between the first shape vector and the first grating vector Relatedly, the first ion beam angle It is based on the equation Certain; The first portion of the substrate is positioned relative to the ion beam at the first ion beam angle. Positioning, the substrate is held on a worktable, and the first ion beam angle It is measured relative to a plane parallel to the worktable; and When the ion beam is at the first ion beam angle Furthermore, when in contact with the first portion of the substrate, the process parameters are adjusted.

9. The method of claim 8, wherein the process parameters include: The duty cycle of the ion beam, the partial scan of the ion beam, the scan rate of the ion beam, the power supply used to generate the ion beam, or any combination of the above process parameters.

10. The method of claim 8, wherein each of the first grating material layer and the second grating material layer comprises one or more of the following: silicon oxide, titanium dioxide, silicon oxide, vanadium oxide, aluminum oxide, indium tin oxide, zinc oxide, tantalum pentoxide, silicon nitride, titanium nitride, or zirconium dioxide, and wherein the hard mask layer comprises silicon oxide, silicon nitride, or a combination of the above materials.

11. The method of claim 10, wherein the first feature includes a recess and is defined by a first side, a second side, and a third side, the first side being formed to a first depth in the first grating material layer, the second side being defined by a second depth in the first grating material layer, the third side extending between the first side and the second side, the first depth being less than the second depth.

12. The method of claim 11, wherein the first grating comprises a first plurality of fins, the first plurality of fins having a first tilt angle relative to the surface normal of the substrate. The height of the first plurality of fins decreases according to a first depth gradient from the first side of the recess to the second side of the recess, and wherein the first ion beam angle Aligned with the first depth gradient of the first grating.

13. The method of claim 12, further comprising: Remove the hard mask layer; and The first plurality of fins are coated with an oxide layer.

14. The method of claim 10, further comprising: When the ion beam is at the first ion beam angle At that time, the substrate is rotated about the central axis of the worktable to a first rotation angle between the ion beam and the first grating vector of the first grating.

15. The method of claim 14, further comprising: After forming the first grating, the first ion beam angle is... Change to the angle with the first ion beam Different second ion beam angles and A second grating is formed in the second grating material layer. The second grating includes a second plurality of fins having a second shape vector and a second grating vector, wherein the second shape vector is the direction in which the depth gradient of the second grating changes, and wherein forming the second grating includes: Determine the second ion beam angle The second ion beam angle and the second tilt angle and the angle between the second shape vector and the second grating vector Relatedly, the second ion beam angle It is based on the equation Certain; The second portion of the substrate is positioned at the second ion beam angle. In the path of the ion beam; and When the ion beam is at the second ion beam angle At that time, the substrate is rotated about the central axis of the stage to a second rotation angle between the ion beam and the second grating vector of the second grating, wherein the ion beam is at the second ion beam angle. The second grating material layer is contacted to form the second plurality of fins, the second plurality of fins having the second tilt angle. The second shape vector and the second grating vector.

16. The method of claim 10, further comprising: After depositing the second grating material layer and before forming the first grating in the second grating material layer, the substrate in which the first grating is formed is planarized to remove a portion of the second grating material layer.

17. A method for forming a grating, comprising: Multiple openings are etched in a hard mask layer, the hard mask layer being disposed on a grating material layer and the grating material layer being disposed on a substrate; The substrate is etched through the plurality of openings in the hard mask layer to form a first grating in the grating material layer. The first grating includes a plurality of fins formed in recesses. The first grating has a first shape vector and a first grating vector. The first shape vector is the direction in which the depth gradient of the first grating changes. Forming the first grating includes: Determine the first ion beam angle The first ion beam angle With the first tilt angle and the angle between the first shape vector and the first grating vector Relatedly, the first ion beam angle It is based on the equation Certain; The first portion of the grating material layer is positioned relative to the ion beam at the first ion beam angle. Positioning: The ion beam can be adjusted at an angle of 15° to 75° relative to a plane parallel to the substrate, while the substrate is held on the worktable; and When the ion beam is at the first ion beam angle At that time, the substrate is rotated about the central axis of the stage to a first rotation angle between the ion beam and the first grating vector of the first grating; and The first grating is etched at a first angle to remove the top portion of the plurality of fins to form a wedge shape, wherein the first shape vector is a wedge vector.

18. The method of claim 17, wherein the recess is defined by a first side, a second side, and a third side, the first side being formed to reach a first depth in the substrate, the second side being defined by a second depth in the substrate, the third side extending between the first side and the second side, and the first depth being less than the second depth.

19. The method of claim 17, further comprising: A second grating is formed in the grating material layer. The second grating includes a second plurality of fins, a second shape vector, and a second grating vector, wherein the second shape vector is the direction in which the depth gradient of the second grating changes, and wherein forming the second grating includes: Determine the second ion beam angle The second ion beam angle With the second tilt angle and the angle between the second shape vector and the second grating vector Relatedly, the second ion beam angle It is based on the equation Certain; The second portion of the substrate is positioned at the second ion beam angle. In the path of the ion beam, a second grating is formed in the grating material layer; The substrate is rotated about the central axis of the stage, such that a second rotation angle is generated between the ion beam and the second grating vector of the second grating; and When the ion beam is at the second ion beam angle The process parameters are adjusted in time to form a second plurality of fins, the second plurality of fins having a second tilt angle relative to the surface normal of the substrate. It also has the second shape vector and the second grating vector, wherein the process parameters include the duty cycle of the ion beam, the partial scan of the ion beam, the scan rate of the ion beam, the power supply for generating the ion beam, or any combination of the above process parameters.

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