How to form multiple lattices

Abstract

To provide a manufacturing process capable of forming a plurality of lattice regions with different lattice profiles.SOLUTION: A method generally comprising depositing a material 499 on one or more protected regions of a waveguide coupler 103 arranged on a substrate 101, comprises: depositing a materia having a thickness 498 that inhibits removal of a lattice material 412 arranged on the waveguide coupler when an ion beam is directed toward the substrate; and directing the ion beam toward the substrate. The method enables a plurality of lattices to be formed in one or more unprotected regions, while no lattices are formed in the protected regions.SELECTED DRAWING: Figure 4D

Description

[Background technology]

[0001] Technical Field TECHNICAL FIELD Embodiments of the present application relate to a method, and more particularly, to a method for forming a plurality of gratings.

[0002] 2. Description of Related Art Virtual reality is generally considered to be a computer-generated simulated environment in which a user has an apparent physical presence. Virtual reality experiences can be generated in three dimensions (3D) and can be viewed using a head-mounted display (HMD), such as glasses or other wearable display devices, that have a near-eye display panel as a lens for displaying a virtual reality environment that replaces the real environment.

[0003] Augmented reality, however, enables an experience in which a user can look through the display lenses of glasses or other HMD devices and still see the surrounding environment, but can also see images of virtual objects that are generated for display and appear as part of this environment. Augmented reality may also include any kind of incoupling (such as acoustic incoupling and haptic incoupling), as well as virtual images, graphics, and videos that enhance or extend the environment the user experiences.

[0004] To provide an augmented reality experience to a user, a virtual image is overlaid on the surrounding environment. Waveguides are used to assist in the image overlay. The generated light is propagated through the waveguide before exiting the waveguide and being overlaid on the surrounding environment. In some implementations, multiple waveguides are stacked or otherwise combined to form an optical device (such as a display lens). Each of the waveguides or waveguide couplers includes a substrate with various grating regions.

[0005] One of the disadvantages in the art is that fabricating different gratings on the same substrate is a time-consuming process. In order to fabricate gratings with different material properties (such as grating orientation and grating depth), different masking steps and methods are required in photolithography. In addition, some photolithography methods do not have the ability to vary the spacing and depth profile of the gratings in different waveguides.

[0006] Therefore, what is needed is a manufacturing process that allows for the formation of multiple grating regions having distinct grating profiles. Summary of the Invention

[0007] Embodiments herein include methods for forming multiple gratings, which allow for faster and cheaper formation of waveguides with a variety of grating profiles.

[0008] In one embodiment, a method of forming a first plurality of gratings is provided, the method including: depositing a protective material over one or more first regions of a waveguide coupler disposed on a substrate, the protective material having a first thickness such that the protective material at least partially inhibits removal of grating material disposed on the waveguide coupler when an ion beam is directed toward the substrate; and directing an ion beam toward the substrate such that at least a portion of the grating material is removed from the one or more first regions of the waveguide coupler, thereby forming a first plurality of gratings. At least one of the first gratings of the plurality of gratings has an angle between about 5° and about 85°.

[0009] In another embodiment, a method of forming a plurality of gratings is provided. The method includes depositing a protective material over one or more protected regions of a waveguide coupler disposed on a substrate, the protective material having a thickness that inhibits removal of grating material disposed on the waveguide coupler when an ion beam is directed toward the substrate, directing an ion beam toward the substrate such that at least a portion of the grating material is removed from one of the one or more unprotected regions of the waveguide coupler, thereby forming a plurality of gratings, and removing the protective material over the one or more protected regions. The one or more unprotected regions are configured to receive an incident light beam from a microdisplay. At least one grating of the plurality of gratings has an angle between about 5° and about 85°.

[0010] In yet another embodiment, a method of forming a first plurality of gratings is provided. The method includes depositing a protective material on one or more protected regions of a waveguide coupler disposed on a substrate, the protective material having a thickness that inhibits removal of grating material disposed on the waveguide coupler when an ion beam is directed toward the substrate, depositing the protective material on at least a portion of one of the unprotected regions, directing an ion beam toward the substrate such that at least a portion of the grating material is removed from one of the one or more unprotected regions of the waveguide coupler, thereby forming a first plurality of gratings, and removing the protective material on the one or more protected regions. The first plurality of gratings has a profile with two different depths. At least one grating of the plurality of gratings has an angle between about 5° and about 85°. Depositing the protective material on at least a portion of one of the unprotected regions includes exposing the material to a plurality of heating pixels or light emitting diodes (LEDs).

[0011] In order that the above-mentioned features of the present disclosure may be understood in detail, a more detailed description of the present disclosure, briefly summarized above, may be obtained by referring to the embodiments. Some embodiments are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings show only exemplary embodiments, and therefore should not be considered as limiting the scope of the present disclosure, which may admit other equally effective embodiments. [Brief description of the drawings]

[0012] [Figure 1A] 1 illustrates a front perspective view of a substrate according to one embodiment. [Figure 1B] 1 illustrates a front perspective view of a waveguide coupler according to one embodiment. [Figure 2A] 1 shows a schematic cross-sectional view of a system according to one embodiment. [Figure 2B] 1 illustrates a front perspective view of a substrate support assembly according to one embodiment. [Figure 2C] 1 shows a schematic diagram of an LED array, according to one embodiment. [Diagram 3] 2 is a flow diagram of method steps for fabricating a waveguide coupler, according to one embodiment. [Figure 4A] 1A-1C show schematic cross-sectional views of unprotected areas in a method of fabricating a waveguide coupler according to one embodiment. [Figure 4B] 1A-1C show schematic cross-sectional views of unprotected areas in a method of fabricating a waveguide coupler according to one embodiment. [Figure 4C] 1A-1C show schematic cross-sectional views of unprotected areas in a method of fabricating a waveguide coupler according to one embodiment. [Figure 4D] 1A-1C show schematic cross-sectional views of unprotected areas in a method of fabricating a waveguide coupler according to one embodiment. [Figure 5A] 1 shows a top view of an unprotected portion with a 2D array of gratings according to one embodiment. [Figure 5B] FIG. 13 shows a side view of an unprotected portion having a 2D array of gratings according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] For ease of understanding, wherever possible, the same reference numerals have been used to designate identical elements that are common to the figures. It is envisioned that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0014] Embodiments of the present application generally relate to a method for forming a plurality of gratings. The method generally includes depositing a material on one or more protected regions of a waveguide coupler disposed on a substrate, the material having a thickness that inhibits removal of the grating material disposed on the waveguide coupler when an ion beam is directed toward the substrate, and directing an ion beam toward the substrate. The method disclosed herein allows for a plurality of gratings or fins to be formed in one or more unprotected regions, while no gratings are formed in the protected regions. The embodiments disclosed herein may be useful for, but are not limited to, forming a plurality of gratings for a waveguide.

[0015] As used herein, the term "about" refers to a + / - 10% variation from the nominal value, and it is to be understood that such variation may be included in any value provided herein.

[0016] 1A shows a front perspective view of a substrate 101 according to one embodiment. The substrate 101 is configured for use in an optical device. The substrate 101 can be any substrate used in the art. For example, the substrate 101 includes a semiconductor material (e.g., a III-V semiconductor such as silicon (Si), germanium (Ge), silicon germanium (SiGe), and / or gallium arsenide (GaAs)). In another example, the substrate 101 includes a transparent material (e.g., glass and / or plastic). The substrate 101 can have any number of insulating, semiconductor, or metal layers on a surface.

[0017] As shown, the substrate 101 includes a plurality of waveguide couplers 103 disposed on a surface thereof. The plurality of waveguide couplers 103 are disposed on the substrate 101 in a grid of rows and columns. It is contemplated that other suitable configurations for disposing the plurality of waveguide couplers 103 on the substrate 101 may be implemented in accordance with embodiments described herein.

[0018] 1B illustrates a front perspective view of a waveguide coupler 103, according to one embodiment. The waveguide coupler 103 is configured to guide electromagnetic radiation (e.g., light). As illustrated, the waveguide coupler 103 includes multiple regions, each of which includes multiple gratings or fins, such as an in-coupling region 102 defined by multiple in-coupling gratings 108, an intermediate region 104 defined by multiple intermediate gratings 110, and an output coupling region 106 defined by multiple output gratings 112.

[0019] The in-coupling region 102 is configured to receive an incident light beam (virtual image) having an intensity from a microdisplay. Each grating of the multiple in-coupling gratings 108 in the in-coupling region 102 splits the incident beam into multiple modes (each beam having one mode). The zeroth order mode (T0) beam is reflected or transmitted. The positive first order mode (T1) beam is totally internally reflected (TIR) ​​through the waveguide coupler 103 to the output coupling region 106. The negative first order mode (T2) beam is reflected or transmitted. The positive first order mode (T3) beam is totally internally reflected (T4) through the waveguide coupler 103 to the output coupling region 106. - The beam 1) propagates through the waveguide coupler 103 in the opposite direction to the beam T1.

[0020] In an embodiment described herein that may be combined with other embodiments described herein, a minimum distance 114 between the incoupling region 102 and the intermediate region 104 is maintained during deposition of the waveguide coupler 103, and a minimum distance 116 between the intermediate region 104 and the output coupling region 106 is maintained during deposition of the waveguide coupler 103. For example, the minimum distance 114 and the minimum distance 116 are less than about 1 mm. In an embodiment described herein that may be combined with other embodiments described herein, the incoupling gratings 108 have a depth distribution 118, the intermediate gratings 110 have a depth distribution 120, and the output gratings 112 have a depth distribution 122. For example, the depth of the incoupling gratings 108 with the depth distribution 118 increases in the x direction, the depth of the intermediate gratings 110 with the depth distribution 120 increases in the x direction, and the depth of the output gratings 112 with the depth distribution 122 increases in the y direction.

[0021] 2A shows a schematic cross-sectional view of a system 200 according to one embodiment. The system 200 is configured to partially etch a substrate (e.g., substrate 101) using an ion beam 210. The system 200 may include any ion beam system used in the art (e.g., an ion beam etching system, a focused ion beam etching system, an electron beam etching system, a reactive ion beam etching system, a full wafer ion system, etc.). As shown, the system 200 includes a substrate support assembly 204, an ion source 201, an extraction electrode 270 having a light emitting diode (LED) array 205, a controller 214, a secondary controller 250, a plurality of heating pixels 216, and a power source 212. It should be understood that the system described below is an exemplary system and may be used or modified with other system scans to achieve aspects of the present disclosure.

[0022] The ion source 201 is configured to emit ions incident on the surface of the substrate 101 in a controlled manner. As shown, the ion source 201 includes an extraction aperture 202. Ions are extracted from the ion source 201 through the extraction aperture 202 as an ion beam 210. The extraction aperture 202 is located on a face 203 of the ion source 201 closest to the substrate 101. The ion beam 210 is directed towards the substrate 101. The ion beam 210 can be a ribbon beam, a spot beam, or a full substrate size beam.

[0023] The substrate support assembly 204 is configured to hold the substrate 101 on the support surface 280. As shown, the substrate support assembly 204 includes a body 206 and an actuator 208. The body 206 of the substrate support assembly 204 is coupled to the actuator 208. The actuator 208 is configured to move the body 206 in a scanning motion along the x-direction and / or the y-direction. In one embodiment, which may be combined with other embodiments described herein, the actuator 208 is configured to tilt the body 206 such that the substrate 101 is positioned at a tilt angle β with respect to the z-axis of the ion source 201. In another embodiment, which may be combined with other embodiments described herein, the actuator 208 is configured to rotate the substrate 101 about the x-axis of the body 206. FIG. 2B illustrates a front perspective view of the substrate support assembly 204, according to one embodiment.

[0024] The controller 214 is configured to control and automate the system 200. As shown, the controller 214 includes a central processing unit (CPU) 215, a memory 217, and support circuits (or I / O) 219. The CPU 215 is one of any form of computer processor used in industrial settings to control various processes and hardware (e.g., pattern generators, motors, and other hardware) and monitor processes (e.g., processing time and substrate position or location). The memory 217 is connected to the CPU 215 and is one or more of readily available memory such as random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, or any other form of local or remote digital storage. Software instructions and data may be coded and stored in the memory 217 for instructing the CPU 215. The support circuits 219 are also connected to the CPU 215 to support the CPU in a conventional manner. The support circuits 219 include conventional caches, power supplies, clock circuits, incoupling / output circuitry, subsystems, and the like.

[0025] The secondary controller 250 is configured to control and automate the LED array 205. As shown, the secondary controller 250 includes a central processing unit (CPU) 291, a memory 293, and support circuits (or I / O) 295. The CPU 291 is one of any form of computer processor used in industrial settings to control various processes and hardware (e.g., pattern generators, motors, and other hardware) and monitor processes (e.g., processing time and substrate position or location). The memory 293 is connected to the CPU 291 and is one or more of readily available memories such as random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, or any other form of local or remote digital storage. Software instructions and data may be coded and stored in the memory 293 for instructing the CPU 291. The support circuits 295 are also connected to the CPU 291 to support the CPU in a conventional manner. The support circuits 295 include conventional caches, power supplies, clock circuits, incoupling / output circuitry, subsystems, and the like.

[0026] A program (or computer instructions) readable by the controller 214 and / or the secondary controller 250 specifies which tasks are executable by the system 200. The controller 214 is configured to communicate with and control the power source 212, the actuator 208, and the secondary controller 250. The controller 214 and the secondary controller 250 are configured to control aspects of the substrate support assembly 204 during processing. A plurality of heating pixels 216 are disposed in the body 206 and coupled to the power source 212. The controller 214 is operable to individually control each of the heating pixels 216 such that a temperature distribution is provided on the back side of the substrate 101 (i.e., the side of the substrate 101 held on the support surface 280) corresponding to at least one of the in-coupling region 102, the intermediate region 104, and the out-coupling region 106.

[0027] The LED array 205 is configured to locally heat the substrate 101. The LED array 205 is positioned on the surface of the face 203 of the ion source 201 closest to the substrate 101 and adjacent to the extraction aperture 202. The widths of the LED arrays 205 extend into and out of the page, respectively.

[0028] 2C illustrates a schematic diagram of an LED array 205, according to one embodiment. As shown, the LED array 205 includes a plurality of individual LEDs 207 arranged in an array of rows and columns. Any number of rows and columns of LEDs 207 may be used. The secondary controller 250 is operable to individually control each of the LEDs of the LED array 205 such that a temperature distribution is provided on the front side of the substrate 101.

[0029] 3 is a flow diagram of steps of a method 300 for fabricating a waveguide coupler (e.g., waveguide coupler 103). Although the steps of method 300 are described with reference to FIGS. 4A-4D, one of ordinary skill in the art will appreciate that any system configured to perform the method steps in any order is within the scope of the embodiments described herein. Method 300 may be stored on or accessible to controller 214 and / or secondary controller 250 as a computer readable medium containing instructions that, when executed by controller CPU 215 and / or secondary controller CPU 291, cause system 200 to perform method 300.

[0030] Method 300 begins at step 301, where a protective material is deposited over one or more protected regions (alternatively referred to as "fully protected regions") of substrate 101. The protective material is configured to protect the one or more protected regions from etching in step 302, while allowing etching of one or more unprotected regions. In one embodiment, the one or more protected regions include intermediate region 104 and out-coupling region 106, and the one or more unprotected regions include in-coupling region 102. The unprotected regions may also include partially unprotected regions (i.e., parts of the regions are protected, while other parts of the regions are not).

[0031] The material is deposited by one of inkjet printing or three-dimensional (3D) printing, according to one embodiment. The material may include a photoresist material. The photoresist material may include, but is not limited to, diazonaphthoquinone, phenol formaldehyde resin, poly(methyl methacrylate), poly(methyl glutarimide), and / or SU-8.

[0032] 4A illustrates a schematic cross-sectional view of a portion 400 of one of the one or more protective regions, according to one embodiment. According to one embodiment, the one or more protective regions include the intermediate region 104 and the output coupling region 106. A material 499 (e.g., a protective material as described above) is disposed on a grating material 412 that is disposed on the waveguide coupler 103 of the substrate 101. A patterned hard mask 413 is disposed on the grating material 412. The grating material 412 may be silicon oxycarbide (SiOC), titanium oxide (TiO x ), TiO x Nanomaterials, Niobium Oxide (NbO x ), niobium-germanium (Nb3Ge), silicon dioxide (SiO2), silicon oxycarbonitride (SiOCN), vanadium(IV) oxide (VO x), aluminum oxide (Al2O3), indium tin oxide (ITO), zinc oxide (ZnO), tantalum pentoxide (Ta2O5), silicon nitride (Si3N4), silicon rich Si3N4, hydrogen doped Si3N4, boron doped Si3N4, silicon carbon nitrate (SiCN), titanium nitride (TiN), zirconium dioxide (ZrO2), germanium (Ge), gallium phosphide (GaP), polycrystalline (PCD), nanocrystalline diamond (NCD), doped diamond containing materials, and any mixtures of the above.

[0033] The material 499 may be deposited by 3D printing or inkjet printing. The material 499 has a thickness 414 that inhibits removal of the grid material 412 when the ion beam 210 is directed towards the substrate 101.

[0034] In optional step 301o, a material is deposited on at least a portion of the one or more partially unprotected regions of the substrate 101. The material is configured to partially protect this portion of the one or more partially unprotected regions from etching in step 302, according to one embodiment.

[0035] In step 302, an ion beam is directed to be incident on the substrate 101. Step 302 may include ion beam etching, focused ion beam etching, etc. In one embodiment, an ion beam (e.g., ion beam 210) is generated by and directed by system 200.

[0036] 4B illustrates a schematic cross-sectional view of one of the one or more completely unprotected regions before, during, and after step 302, according to one embodiment. In one embodiment described herein, which may be combined with other embodiments described herein, no material 499 is deposited on top of the grating material 412 in the unprotected region in step 301. In one embodiment, the unprotected region may be an in-coupling region 102.

[0037] In step 302, the ion beam 210 is directed toward the substrate 101, where the ion beam 210 forms a plurality of incoupling gratings 108 in the grating material 412 exposed by the patterned hard mask 413, for example, by etching over a duration corresponding to steps 401-406. Since the thickness of the material 499 above the hard mask 413 is uniform in this example, each grating of the plurality of incoupling gratings 108 formed over steps 401-406 has the same depth 415 in step 406. Thus, the entire grating of the plurality of incoupling gratings 108 can have approximately the same dimensions, forming a consistently uniform grating profile. Any of the gratings described herein have an angle θ that can vary from about 5° to about 85° (i.e., the grating is tilted with respect to the surface of the substrate 101).

[0038] FIG. 4C shows a schematic cross-sectional view of one of the partially unprotected and completely unprotected regions before, during, and after step 302, according to one embodiment. In the embodiment shown in FIG. 4C, optional step 301o is performed. Thus, a material 499 is disposed on at least a portion of the partially unprotected region. The material 499 has various regions of different thicknesses (e.g., a first thickness 416 and a second thickness 417). The second thickness 417 is less than the first thickness 416, such that in step 406, a first portion 418 of the grating corresponding to the first thickness has a depth 419 that is less than a depth 420 of a second portion 421 of the grating corresponding to the second thickness. Thus, different portions of the same gratings have different depth profiles, forming a depth profile with two different depths. In some embodiments, the first thickness 416 is approximately zero (i.e., little or no material is deposited on this portion). In some embodiments, the first thickness 416 is thick enough that no lattice develops in this area, resulting in a fully protected region. In some embodiments, multiple thicknesses of material are included (e.g., three or more thicknesses).

[0039] If no material 499 was deposited on the unprotected areas of the grating material 412, then the first portion 418 of the grating may have a depth 419 that is less than the depth 420 of the second portion 421 of the grating in step 406.

[0040] In one embodiment described herein, which may be combined with other embodiments described herein, each of the heating pixels 216 may be individually controlled to provide a temperature distribution corresponding to a partially unprotected area on the backside of the substrate 101. In some embodiments, the portions of the material 499 that experience a higher temperature react faster than the portions that experience a lower temperature. Thus, the hotter portions are etched deeper, resulting in a deeper lattice at the hotter portions than at the colder portions. In some embodiments, the portions of the material 499 that experience a higher temperature are etched slower than the portions that experience a lower temperature. Thus, the hotter portions are etched shallower, resulting in a shallower lattice at the hotter portions than at the colder portions. For example, when the material 499 is partially removed during an etching process, the increased temperature of the hotter portions will result in more material being removed than the colder portions.

[0041] In another embodiment described herein, which may be combined with other embodiments described herein, the variation in etch rate is achieved by individually controlling each of the LEDs of the LED array 205 to provide a temperature distribution corresponding to the protected region on the front side of the substrate 101. In some embodiments, a uniform material 499 is deposited over the protected region, and the depth of the grating (e.g., grating 418) formed is controlled by the dose of light irradiated by the LEDs. The depth of the grating formed is controlled by increasing the irradiation of a portion of the material 499. In some embodiments, the portions of the material 499 that receive a high dose of light are etched faster than the portions that receive a low dose of light. Thus, the high dose portions are etched deeper, providing a deeper grating in the high dose portions than in the low dose portions. In some embodiments, the portions of the material 499 that receive a high dose of light are etched slower than the portions that receive a low dose of light. Thus, the high dose portions are etched less deeply, providing a shallower grating in the high dose portions than in the low dose portions. In some embodiments, grayscale lithography is performed on the uniform material 499 to control the depth of the grating (eg, grating 418).

[0042] 4D shows a schematic cross-sectional view of one of the one or more partially unprotected regions before, during, and after step 302, according to one embodiment. In the embodiment shown in FIG. 4D, optional step 301o is performed. Thus, material 499 is disposed over at least a portion of the partially unprotected region. Material 499 has a thickness 498 that varies with position. Thus, different portions of the same gratings may be formed having different depth profiles that vary with the thickness of material 499. Although the variation in thickness 498 of material 499 is linear according to one embodiment, thickness 498 may vary in any other manner and may even vary in two dimensions across the gratings.

[0043] In any of the above embodiments, the elements of the patterned hard mask 413 may have different widths 451 and therefore the fins of the resulting incoupling gratings 108 may have different widths. In any of the above embodiments, the elements of the patterned hard mask 413 may have different spacings 452 and therefore the spacing between the fins of the resulting incoupling gratings 108 may vary. In any of the above embodiments, the elements of the patterned hard mask 413 may have different widths 451 and different spacings 452 and therefore the fins of the multiple incoupling gratings 108 may have different widths and different spacings between the fins.

[0044] In step 303, material 499 is removed from the protected regions. In one embodiment, the protected regions include the intermediate region 104 and the output coupling region 106. The material may be removed using any method standard in the art, such as oxygen gas (O2) ashing. Thus, the unprotected regions (e.g., the incoupling region 102) have a plurality of gratings (e.g., the plurality of incoupling gratings 108) formed therein, and the protected regions (e.g., the intermediate region 104 and the output coupling region 106) have no gratings formed therein.

[0045] In optional step 303o, material is removed from the partially unprotected areas if any material still remains after the etch of step 302. Material may be removed as described above for step 303.

[0046] In some embodiments, steps 301-303 are repeated, but the protected and unprotected regions are different from previous steps 301-303. In one embodiment, the protected regions include the in-coupling region 102 and the out-coupling region 106, and the unprotected regions include the intermediate region 104. In one embodiment, the protected regions include the in-coupling region 102 and the intermediate region 104, and the unprotected regions include the out-coupling region 106. For each of the unprotected regions, the method 300 can be modified to create different gratings of different thicknesses, widths, and profiles (e.g., the in-coupling region 102 has multiple in-coupling gratings 108 formed in the embodiment shown in FIG. 4B, and the intermediate region 104 has multiple intermediate gratings 110 formed in the embodiment shown in FIG. 4C). In other embodiments, steps 301o and 303o are also repeated. Thus, the method 300 allows for creating different regions with different grating characteristics.

[0047] Although the above description of method 300 is illustrated with a one-dimensional array of gratings (e.g., gratings 418), a two-dimensional (2D) array of gratings may also be formed by method 300. FIG. 5A illustrates a top view of an unprotected portion 500 having a 2D array 520 of gratings 521, according to one embodiment. FIG. 5B illustrates a side view of an unprotected portion 500 having a 2D array 520 of gratings 521, according to one embodiment. As shown, the 2D array 520 has rows 501 and columns 502 of gratings 521. Any number of rows 501 and columns 502 may be included in the 2D array 520. Although the 2D array 520 shown in FIG. 5A has gratings 521 arranged in a grid pattern, any pattern may be utilized.

[0048] The critical dimensions (CD) of the gratings 521 in the x-direction (e.g., x-width, d x ) can be the same or different from each other. y ) can be the same or different from each other.z ) can be the same or different from each other. y ) can be the same or different from each other. The angles θ1, θ2, θ3, θ4 of the multiple gratings 521 can be the same or different from each other.

[0049] The inter-lattice spacing between individual lattices 521 in the x-direction (e.g., the x-distance, S x ) can be the same or different from each other. The inter-lattice spacing between the individual lattices 521 in the y direction (e.g., y distance, s y ) can be the same or different from each other.

[0050] The gratings 521 may have a rectangular shape (e.g., gratings 510, 510'), a square shape (e.g., gratings 511, 511'), an L-shape (e.g., gratings 513, 513'), a circular shape (e.g., grating 516), and / or an island shape (e.g., 514). Any combination of gratings 521 of any shape may be included. While examples of grating 251 shapes are given, any other feasible shape is also envisioned. The gratings 521 may also include voids 515 (i.e., portions that extend into the underlying substrate 101).

[0051] As discussed above, a method for forming a plurality of gratings is provided that includes depositing a material on one or more protected regions of a waveguide coupler disposed on a substrate, the material having a thickness that inhibits removal of the grating material disposed on the waveguide coupler when an ion beam is directed toward the substrate. The method disclosed herein allows for a plurality of gratings to be formed in one or more unprotected regions, while no gratings are formed in the protected regions.

[0052] While the foregoing is directed to examples of the disclosure, other and further examples of the disclosure may be devised without departing from the basic scope thereof, the scope of which is determined by the claims that follow.

Claims

1. 1. A method of forming a first plurality of gratings, comprising the steps of: disposing a protective material between portions of the patterned hard mask on a grating material, the protective material having a thickness from a top planar surface of the grating material to a top surface of the protective material, the thickness of the protective material varying along the top planar surface of the grating material; and etching the grating material to remove at least a portion of the grating material such that the first plurality of gratings are formed in the grating material, the first plurality of gratings including a depth profile corresponding to the thickness of the protective material, the protective material at least partially inhibiting removal of the grating material such that at least two gratings of the first plurality of gratings have different depths from one another.

2. disposing the protective material over a first portion and a second portion of the lattice material, whereby the protective material completely inhibits removal of the lattice material in the first portion; The method of claim 1 , further comprising: removing the protective material over the second portion.

3. The method of claim 2 , wherein the protective material disposed over the first portion is thicker than the protective material disposed over the second portion.

4. The method of claim 1 , wherein the thickness of the protective material varies two-dimensionally across the first plurality of gratings.

5. The method of claim 1 , wherein the protective material is deposited by one of inkjet printing and three-dimensional printing.

6. The method of claim 1 , wherein the etching is performed by an ion beam.

7. 1. A method of forming a plurality of gratings, comprising the steps of: disposing a protective material between portions of the patterned hard mask on a first portion of the grating material adjacent a second portion of the grating material, the protective material including a thickness from a top planar surface of the grating material to a top surface of the protective material; and etching the first and second portions of the grating material to remove at least a portion of the grating material to form a first plurality of gratings in the first portion and a second plurality of gratings in the second portion, the first plurality of gratings having a first depth less than a second depth of the second plurality of gratings and a depth profile corresponding to the thickness of the protective material, the protective material at least partially inhibiting removal of the grating material in the first portion.

8. The method of claim 7 further comprising disposing the protective material over a second portion of the grid material.

9. The method of claim 8 , wherein the protective material disposed over the first portion is thicker than the protective material disposed over the second portion.

10. The method of claim 8 , wherein the protective material disposed over the second portion has a second thickness that varies across the grid material.

11. The method of claim 10 , wherein the thickness of the protective material disposed over the first portion varies linearly across the grating material.

12. The method of claim 7 , wherein at least one grating of the first plurality of gratings has a different thickness than other gratings of the first plurality of gratings.

13. The method of claim 7 , wherein the depositing of the protective material is repeated and the etching is repeated.

14. 1. A method of forming a plurality of gratings, comprising the steps of: disposing a protective material between portions of the patterned hard mask on a first portion of a grating material and a second portion of the grating material adjacent to the first portion, the protective material having a first thickness from a planar top surface of the first portion to a top surface of the protective material and a second thickness from a planar top surface of the second portion to a top surface of the protective material; and etching a first and second portion of the grating material such that a first plurality of gratings is formed in the first portion, the first plurality of gratings including a depth profile corresponding to the first thickness of the protective material, the protective material at least partially inhibiting removal of the grating material in the first portion and completely inhibiting removal of the grating material in the second portion.

15. The method of claim 14 , further comprising exposing the protective material to a plurality of heating pixels or light emitting diodes (LEDs).

16. The method of claim 15 , wherein each of the plurality of heating pixels or LEDs is individually controlled.

17. The method of claim 16 , further comprising providing a temperature distribution corresponding to the first portion to a backside of a substrate disposed beneath the grating material.

18. The method of claim 14 , wherein at least one grating of the first plurality of gratings has a different thickness than other gratings of the first plurality of gratings.

19. The method of claim 14 , wherein the protective material comprises a photoresist.

20. The method of claim 19 , wherein the protective material comprises SU-8.

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