Method for manufacturing an optical device structure

Abstract

The implementations described herein provide methods of forming optical device structures. The methods utilize rotation of a substrate to form optical device structures on the substrate and utilize tunability of etch rates of one of a patterned resist disposed above the substrate and a device layer or the substrate to form optical device structures without requiring multiple photolithographic patterning steps and angled etching steps.

Description

TECHNICAL FIELD

[0001] Embodiments of the present invention generally relate to optical devices for augmented reality, virtual reality, and mixed reality. More particularly, embodiments described herein provide for forming blazed optical device structures. BACKGROUND

[0002] Virtual reality is generally considered to be a computer-generated simulated environment in which a user has a strong sense of physical presence. Virtual reality experiences can be generated in 3D form and viewed using a head-mounted display (HMD), such as glasses or other wearable display devices that have display panels close to the eyes as lenses, to display a virtual reality environment that replaces the actual environment.

[0003] However, augmented reality enables an experience in which a user can still see the surrounding environment through the display lenses of glasses or other HMD devices, as well as see images of virtual objects that are generated to be displayed and appear as part of the environment. Augmented reality can include any type of input, such as audio and haptic input, as well as virtual images, graphics, and video that enhance or augment the environment for the user’s experience. As an emerging technology, augmented reality faces many challenges and design constraints.

[0004] One such challenge is displaying virtual images that are overlaid on the surrounding environment. Optical devices including waveguide combiners, such as augmented reality waveguide combiners, and planar optical devices, such as metasurfaces, are used to help overlay the images. The generated light is propagated through the optical device until the light exits the optical device and is overlaid on the surrounding environment. The optical device can need structures that have a blazed angle relative to the surface of the optical device substrate. It is known that fabricating blazed optical device structures using one or more angled etching tools requires multiple photolithographic patterning steps and angled etching steps. The multiple photolithographic patterning steps and angled etching steps increase the fabrication time and increase the cost.

[0005] Accordingly, there is a need in the art for improved methods of forming optical devices including blazed optical device structures using angled etching tools. SUMMARY

[0006] In one embodiment, a method is provided. The method includes patterning a substrate in a beam path at a first rotational angle A substrate is positioned. The beam is configured to be projected onto the substrate surface at a beam angle θ relative to the normal to the substrate surface. A patterned resist is formed on the substrate, wherein the patterned resist comprises two or more resist structures and one or more gaps. Each of the resist structures has a width, and each of the gaps is defined by an adjacent resist structure and has a linewidth defined by the adjacent resist structure. The method includes etching the substrate positioned at a first rotation angle using the beam. The substrate at the location, and rotate the substrate to the second rotation angle. The method further includes etching the sidewalls of the resist structure oriented towards the beam, thereby reducing the width of the resist structure and increasing the linewidth of the gap. And use beam etching at the first rotation angle A substrate at a location, and the formation of two or more optical device structures in the substrate. Forming the optical device structures includes repeatedly rotating the substrate to a second rotation angle. The sidewalls of the resist structure were etched using a beam, and the substrate was rotated to a first rotation angle. The substrate is then etched with a beam until the resist structure is removed or the gap linewidth has a predetermined linewidth.

[0007] In another embodiment, a method is provided. The method includes rotating the beam path at a first angle... A substrate is positioned. The beam is configured to be projected onto the substrate surface at a beam angle θ relative to the normal to the substrate surface. A device layer is formed over the substrate, and a patterned resist is formed on the device layer. The patterned resist includes two or more resist structures and one or more gaps. Each of the resist structures has a width, and each of the gaps is defined by an adjacent resist structure and has a linewidth defined by the adjacent resist structure. The method includes etching with the beam at a first rotation angle. Position the device layer of the substrate and rotate the substrate to the second rotation angle. The method further includes etching the sidewalls of the resist structure oriented towards the beam, thereby reducing the width of the resist structure and increasing the linewidth of the gap. And use beam etching at the first rotation angle The device layer at the location, and the formation of two or more optical device structures within the device layer. Forming the optical device structures includes repeatedly rotating the substrate to a second rotation angle. The sidewalls of the resist structure were etched using a beam, and the substrate was rotated to a first rotation angle. The device layer is then etched with a beam until the resist structure is removed or the gap linewidth has a predetermined linewidth.

[0008] In yet another embodiment, a method is provided. The method includes positioning a substrate at a first rotational angle in a beam path. The beam is configured to project onto a surface of the substrate at a beam angle θ relative to a surface normal of the substrate. A patterned resist is formed on the substrate, where the patterned resist includes two or more resist structures and one or more gaps. Each of the resist structures has a width, and each of the gaps is defined by adjacent resist structures and has a line width defined by the adjacent resist structures. The substrate is etched with a beam generated from a substrate etch chemistry, and the resist structures are etched with a beam generated from a resist etch chemistry different from the substrate etch chemistry. The method further includes etching the substrate positioned at the first rotational angle with the beam generated from the substrate etch chemistry, and rotating the substrate to a second rotational angle and etching sidewalls of the resist structures with the beam at the beam angle θ. The beam generated from the resist etch chemistry etches the resist structure sidewalls oriented toward the beam such that the width of the resist structures decreases and the line width of the gaps increases. The method further includes rotating the substrate to the first rotational angle and etching the substrate positioned at the first rotational angle with the beam generated from the substrate etch chemistry, and forming two or more optical device structures in the substrate. Forming the optical device structures includes repeatedly rotating the substrate to the second rotational angle and etching the resist structure sidewalls with the beam generated from the resist etch chemistry, and rotating the substrate to the first rotational angle and etching the substrate with the beam generated from the substrate etch chemistry until the resist structures are removed or the line width of the gaps has a predetermined line width. BRIEF DESCRIPTION OF DRAWINGS

[0009] So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, can be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, as the scope of the disclosure can allow for other equally effective embodiments.

[0010] FIG. 1A is a perspective front view of an optical device in accordance with embodiments described herein.

[0011] FIG. 1B and FIG. 1C is a schematic cross-sectional view of a plurality of device structures in accordance with embodiments described herein.

[0012] FIG. 2is a schematic side view of an angled etching system according to embodiments described herein.

[0013] FIG. 3 is a schematic cross-sectional view of an angled etching system according to embodiments described herein.

[0014] FIG. 4 is a flowchart of a method for forming a plurality of blazed device structures of an optical device structure according to embodiments described herein.

[0015] FIGS. 5A-5E is a schematic cross-sectional view of a portion of a substrate during a method for forming a plurality of blazed device structures according to embodiments described herein.

[0016] FIGS. 5F-5J is a schematic top view of a portion of a substrate during a method for forming a plurality of blazed device structures according to embodiments described herein.

[0017] To facilitate an understanding of this description, like reference characters are used to identify like elements throughout the discussion. Elements and features of one implementation can be beneficially incorporated into other implementations without further recitation. DETAILED DESCRIPTION

[0018] Embodiments of the present invention generally relate to optical devices for augmented reality, virtual reality, and mixed reality. More particularly, embodiments described herein provide a method for forming an optical device structure. The method utilizes rotation of a substrate to form an optical device structure on the substrate and utilizes tunability of etch rate of one of a patterned resist and a device layer disposed above the substrate or the substrate to form the optical device structure without multiple photolithographic patterning steps and angled etching steps.

[0019] In one embodiment, the method includes positioning a substrate at a first rotation angle in a beam path, the beam configured to project onto a surface of the substrate at a beam angle θ relative to a surface normal of the substrate. The substrate has a patterned resist formed thereon. The patterned resist includes two or more resist structures. Each one of the resist structures has a width and one or more gaps. Each of the gaps is defined by adjacent resist structures and has a line width defined by the adjacent resist structures. The substrate positioned at the first rotation angle is etched with the beam. The substrate is rotated to a second rotation angle and the sidewalls of the resist structures are etched with the beam at the beam angle θ such that the width of the resist structures decreases and the line width of the gaps increases. The substrate is rotated to the first rotation angle and the substrate positioned at the first rotation angle a substrate. Two or more optical device structures are formed in the substrate. Forming the optical device structures includes repeatedly rotating the substrate to a second rotation angle and etching a sidewall of the resist structure with the beam, and rotating the substrate to a first rotation angle and etching the substrate with the beam until the resist structure is removed or a line width of the gap has a predetermined line width.

[0020] FIG. 1A A perspective front view of an optical device 100 is shown. It should be understood that the optical device 100 described below is an example optical device. In one embodiment, which can be combined with other embodiments described herein, the optical device 100 is a waveguide combiner, such as an augmented reality waveguide combiner. In another embodiment, which can be combined with other embodiments described herein, the optical device 100 is a planar optical device, such as a metasurface. The optical device 100 includes a plurality of device structures 102 disposed in a substrate 101 (as shown) or disposed on a substrate (as shown). As shown, the device structures 102 are formed in a device layer 114, which is formed on the substrate 101. The device structures 102 can be nanostructures having sub-micron dimensions, e.g., nano-sized dimensions, such as a critical dimension less than 1 pm. In one embodiment, which can be combined with other embodiments described herein, regions of the device structures 102 correspond to one or more gratings 104, such as a first grating 104a, a second grating 104b, and a third grating 104c. In one embodiment, which can be combined with other embodiments described herein, the optical device 100 is a waveguide combiner that includes at least the first grating 104a corresponding to an input-coupling grating and the third grating 104c corresponding to an output-coupling grating. A waveguide combiner according to embodiments, which can be combined with other embodiments described herein, can include the second grating 104b corresponding to an intermediate grating. FIG. 1B FIG. 1C FIG. 1C

[0021] FIG. 1B and FIG. 1C ​​​is a schematic cross-sectional view of a plurality of device structures 102. In one embodiment, which can be combined with other embodiments described herein, the device structures 102 are blazed device structures 106 of a flat optical device, such as a metasurface. The method 400 described herein forms the blazed device structures 106. In another embodiment, which can be combined with other embodiments described herein, the device structures 102 are blazed device structures 106 of a waveguide combiner, such as an augmented reality waveguide combiner. A waveguide combiner according to embodiments, which can be combined with other embodiments described herein, can include blazed device structures 106 in at least one of the gratings 104. Each of the blazed device structures 106 includes a blazed surface 108, a sidewall 112, a depth h, and a line width d. The blazed surface 108 has a plurality of steps 110. In one embodiment, which can be combined with other embodiments described herein, the blazed surface 108 includes at least 16 steps 110, such as greater than 32 steps 110, such as 64 steps 110. The blazed surface 108 has a blaze angle g. The blaze angle g is an angle between the blazed surface 108 and a surface parallelism p of the substrate 101, and an angle between a surface normal of the substrate 101 and a facet normal f of the blazed surface 108. The depth h corresponds to a height of the sidewall 112, and the line width d corresponds to a distance between sidewalls 112 of adjacent blazed device structures 106.

[0022] In one embodiment, which can be combined with other embodiments described herein, the blaze angle g of two or more blazed device structures 106 is different. In another embodiment, which can be combined with other embodiments described herein, the blaze angle g of two or more blazed device structures 106 is the same. In one embodiment, which can be combined with other embodiments described herein, the depth h of two or more blazed device structures 106 is different. In another embodiment, which can be combined with other embodiments described herein, the depth h of two or more blazed device structures 106 is the same. In one embodiment, which can be combined with other embodiments described herein, the line width d of two or more blazed device structures 106 is different. In another embodiment, which can be combined with other embodiments described herein, the line width d of one or more blazed device structures 106 is the same.

[0023] The substrate 101 may also be selected to transmit a suitable amount of light of a desired wavelength or wavelength range (such as one or more wavelengths from about 100 nanometers to about 3000 nanometers). Without limitation, in some embodiments, the substrate 101 is configured such that the IR to UV region of the transmission spectrum of the substrate 101 is greater than or equal to about 50% to about 100%. The substrate 101 can be formed of any suitable material, provided that the substrate 101 can sufficiently transmit light of the desired wavelength or wavelength range and can adequately support the blazed device structure 106 described herein (when the blazed device structure 106 is formed in the device layer 114). The choice of substrate may include substrates of any suitable material, including but not limited to amorphous dielectrics, non-amorphous dielectrics, crystalline dielectrics, silicon oxide, polymers, and combinations thereof. In some embodiments that may be combined with other embodiments described herein, the substrate 101 comprises a transparent material. Suitable examples may include oxides, sulfides, phosphides, tellurides, or combinations thereof. In one example, substrate 101 includes silicon (Si), silicon dioxide (SiO2), germanium (Ge), silicon-germanium (SiGe), sapphire, and high-refractive-index transparent materials, such as high-refractive-index glass.

[0024] In some embodiments that can be combined with other embodiments described herein, device layer 114 includes, but is not limited to, materials containing silicon oxycarbide (SiOC), materials containing titanium dioxide (TiO2), materials containing silicon dioxide (SiO2), and materials containing vanadium oxide (IV) (VO2). x The material may be one or more of the following: aluminum oxide (Al2O3), aluminum-doped zinc oxide (AZO), indium tin oxide (ITO), tin dioxide (SnO2), zinc oxide (ZnO), tantalum pentoxide (Ta2O5), silicon nitride (Si3N4), zirconium dioxide (ZrO2), niobium oxide (Nb2O5), cadmium stannate (Cd2SnO4), or silicon carbonitride (SiCN). In some embodiments that may be combined with other embodiments described herein, the material of device layer 114 may have a refractive index between about 1.5 and about 2.65. In other embodiments that may be combined with other embodiments described herein, the material of device layer 114 may have a refractive index between about 3.5 and about 4.0.

[0025] FIG. 2is a schematic side view of an angled etch system 200. It should be understood that the angled etch system 200 described below is an exemplary angled etch system, and other angled etch systems can be used with optical devices 100 having a blazed device structure 106, or modified to manufacture optical devices 100 having a blazed device structure 106, in accordance with embodiments of the present disclosure.

[0026] The angled etch system 200 includes an ion beam chamber 202. A power source 204, a first gas source 206, and a second gas source are coupled to the ion beam chamber 202. In one embodiment, which can be combined with other embodiments described herein, the power source 204 is a radio frequency (RF) power source. The first gas source 206 is in fluid communication with an interior volume 205 of the ion beam chamber 202. The first gas source 206 is an inert gas source that supplies an inert gas, such as argon, hydrogen, or helium, to the ion beam chamber 202. The second gas source 208 is in fluid communication with the interior volume 205 of the ion beam chamber 202. The second gas source 208 is a process gas source that supplies a process gas to the ion beam chamber 202. The process gas includes, but is not limited to, one or more of a chlorine-containing gas, a fluorine-containing gas, a bromine-containing gas, an oxygen-containing gas, a silicon-containing gas, a nitrogen-containing gas, a hydrogen-containing gas, and the like. In embodiments of the method 400 described herein, which can be combined with other embodiments described herein, two or more process gases can be used.

[0027] The first process gas can have a substrate etch chemistry selective to the resist material. The etch selectivity of the first process gas having the substrate etch chemistry provides a selectivity of about 5: 1 or greater of the substrate material relative to the resist material (described below). The etch selectivity of the first process gas having the device material etch chemistry provides a selectivity of about 5: 1 or greater of the device material relative to the resist material. In one embodiment, which can be combined with other embodiments described herein, the substrate etch chemistry includes a chlorine-containing gas, a fluorine-containing gas, or a combination thereof. In another embodiment, which can be combined with other embodiments described herein, the device material etch chemistry includes a chlorine-containing gas, a fluorine-containing gas, or a combination thereof.

[0028] The second process gas can have a resist etch chemistry selective to the substrate material or the device material. The etch selectivity of the second process gas having the resist etch chemistry provides a selectivity of about 10: 1 or greater of the resist material relative to the substrate material, or a selectivity of about 10: 1 or greater of the resist material relative to the device material. In one embodiment, which can be combined with other embodiments described herein, the resist etch chemistry includes oxygen (O2) and carbon tetrafluoride (CF4). In another embodiment, which can be combined with other embodiments described herein, the resist etch chemistry includes argon (Ar), nitrogen (N2), and hydrogen (H2). In another embodiment, which can be combined with other embodiments described herein, the resist etch chemistry includes nitrogen (N2) and hydrogen (H2).

[0029] In operation, a plasma is generated in the ion beam chamber 202 by applying RF power to the inert and process gases provided to the interior volume 205 of the ion beam chamber 202 via the power source 204 to generate a plasma. Ions of the plasma of the inert and process gases are extracted via the apertures 210 of the extraction plate 212 to generate the ion beam 216. The apertures 210 of the ion beam chamber 202 are operable to direct the ion beam 216 at an angle a with respect to a reference plane 218 oriented normal to the substrate 101 (i.e., surface normal s). The ion beam 216 includes, but is not limited to, a point beam, a strip beam, or a full substrate size beam. Depending on the process gas utilized, the generated ion beam 216 contains one of a substrate etch chemistry, a device material etch chemistry, or a resist etch chemistry.

[0030] The substrate 101 is held on a platen 214 coupled to a first actuator 219. The first actuator 219 can be a linear actuator, a rotary actuator, a stepper motor, or the like, configured to move the platen 214 in a scan motion along the y- and / or z-directions. In one embodiment, which can be combined with other embodiments described herein, the first actuator 219 is further configured to tilt the platen 214 such that the substrate 101 is positioned at a tilt angle β with respect to the x-axis of the ion beam chamber 202. The angle a and the tilt angle β result in a beam angle Θ with respect to the reference plane 218 normal to the substrate 101. A second actuator 220 can also be coupled to the platen 214 to rotate the substrate 101 about the x-axis of the platen 214.

[0031] FIG. 3is a schematic cross-sectional view of an angled etching system 300. It should be understood that the angled etching system 300 described below is an exemplary angled etching system, and other angled etching systems can be used with optical devices 100 having a blazed device structure 106, or modified to fabricate optical devices 100 having a blazed device structure 106, in accordance with embodiments of the present disclosure.

[0032] The angled etching system 300 includes an electron beam chamber 302. A power source 304, a first gas source 306, and a second gas source 308 are coupled to the electron beam chamber 302. The first gas source 306 and the second gas source 308 are in fluid communication with an interior volume 305 of the electron beam chamber 302. For example, the first gas source 306 and the second gas source 308 can extend through the electrode 322, or the electrode 322 can include a plurality of apertures to function as a gas delivery showerhead. The first gas source 306 is an inert gas source that supplies an inert gas to the electron beam chamber 302 (as described above). The second gas source 308 is a process gas source that supplies a process gas to the ion beam chamber 202 (as described above). In embodiments of the method 400 described herein, which can be combined with other embodiments described herein, two or more process gases can be used. The two or more process gases include the substrate etch chemistry, the device material etch chemistry, and the resist etch chemistry described herein.

[0033] The substrate 101 is held on a platen 314 coupled to a first actuator 321. The first actuator 321 can be a linear actuator, a rotary actuator, a stepper motor, or the like, configured to raise and lower the platen 314 within the electron beam chamber 302. A second actuator 320 can also be coupled to the platen 314 to rotate the substrate 101 about a vertical axis of the platen 314. The platen 314 includes an electrode 324 disposed therein. In one embodiment, the electrode 324 is a clamping device, such as an electrostatic chuck, for securing the substrate 101 to the electrode during processing of the substrate 101. Power from the power source 304 can be used to bias the electrode 324 to clamp the substrate 101 to the electrode 324 or to affect electron bombardment on the substrate 101.

[0034] In operation, a plasma is generated in the electron beam chamber 302 by various bulk and surface processes (e.g., by inductive coupling). It is believed that ions generated by the inductively coupled plasma are affected by an electric field that causes the ions generated by the plasma of the inert gas and the process gas to bombard the electrode 322. Other plasma generation processes can be utilized in accordance with embodiments described herein, such as a capacitively coupled arrangement, a hollow cathode arrangement, a direct current electrode bias, or an electron beam plasma generation process.

[0035] The ion bombardment of the electrode 322 is believed to cause the electrode 322 to emit secondary electrons. High-energy secondary electrons with negative charge are emitted from the electrode 322. As such, the electron beam 316 is accelerated from the electrode 322 at a beam angle Θ with respect to a reference plane 318 oriented normal to the substrate 101 (i.e., the surface normal s). The electron beam 316 includes, but is not limited to, a point beam, a strip beam, or a full substrate size beam. Depending on the processing gas utilized, the resulting electron beam 316 contains one of a substrate etch chemistry, a device material etch chemistry, or a resist etch chemistry.

[0036] As described herein, the ion beam 216 generated from the angled etching system 200 (e.g., an ion beam etching system) and the electron beam 316 generated from the angled etching system 300 (e.g., an electron beam etching system) are collectively referred to as a beam 516 (as FIGS. 5A-5J As shown, the beam 516 is one of an ion beam or an electron beam. In embodiments of the method 400, which can be combined with other embodiments described, the beam 516 has one of a substrate etch chemistry, a device material etch chemistry, or a resist etch chemistry in the operations of the method 400 described herein. In some embodiments, which can be combined with other embodiments described herein, at least the substrate etch chemistry and the resist etch chemistry are different. In other embodiments, which can be combined with other embodiments described herein, at least the device material etch chemistry and the resist etch chemistry are different. As described herein, the tunability of the etch rate of the resist material 506 and one of the device layer 114 or the substrate 101, along with the rotation of the substrate 101, forms a blazed optical device structure without the need for multiple lithographic patterning steps and angled etching steps.

[0037] FIG. 4 is a flowchart of a method 400 for forming a plurality of blazed device structures 106 of an optical device structure 100 as FIGS. 5A-5E and FIGS. 5F-5J is a flowchart of a method 400 for forming a plurality of blazed device structures 106 of an optical device structure 100 as FIGS. 5A-5E is a schematic cross-sectional view of a portion 501 of the substrate 101 during the method 400. FIGS. 5F-5J is a schematic top view of the portion 501 of the substrate 101 during the method 400.

[0038] To facilitate explanation, reference will be made to the angled etching system 200 of FIG. 2 and the angled etching system 300 of FIG. 3Method 400 is described using an angled etching system 300. However, it should be noted that angled etching systems other than angled etching systems 200 and 300 can also be used in combination with method 400. In one embodiment that can be combined with other embodiments described herein, portion 501 may correspond to a portion or the entire surface of a substrate 101 of a planar optics to form a plurality of blazed device structures 106 thereon. In another embodiment that can be combined with other embodiments described herein, portion 501 may correspond to a portion or the entire surface of a substrate 101 of a waveguide combiner to form a plurality of blazed device structures 106 thereon. Portion 501 may correspond to one or more gratings 104. Although FIGS. 5A-5E and FIGS. 5F-5J An etched substrate 101 is depicted such that a blazing device structure 106 is disposed in the substrate, but a device layer 114 (as described above) may be disposed on the surface 103 such that the blazing device structure 106 is disposed in the device layer 114.

[0039] At operation 401, such as FIG. 5A and FIG. 5F As shown, the substrate 101 is positioned at a first rotation angle defined by the reference line 502. Place, such as FIG. 5F As shown. In one embodiment that can be combined with other embodiments described herein, the first rotation angle The 0° is defined by reference line 502. The substrate 101 or device layer 114 (not shown) includes a patterned resist 504 disposed thereon. The patterned resist 504 comprises a resist material 506, which is patterned into a plurality of resist structures 508 disposed on the surface 103 of the substrate 101. The resist material 506 of the patterned resist 504 is selected based on substrate etching chemistry (in embodiments where substrate 101 is etched to form the scintillation device structure 106) or device material etching chemistry (in embodiments where device layer 114 is etched to form the scintillation device structure 106). In one embodiment, the resist material 506 is a photosensitive material, such that the patterned resist 504 can be patterned by photolithography (e.g., photolithography or digital photolithography) or by laser ablation to form a plurality of resist structures 508. In one embodiment, the resist material 506 is an imprintable material, and the patterned resist 504 can be patterned via nanoimprint processing to form a plurality of resist structures 508. In another embodiment, which can be combined with other embodiments described herein, the resist material 506 is a hard mask material, and the patterned resist 504 is patterned via one or more etching processes to form a plurality of resist structures 508. In yet another embodiment, which can be combined with other embodiments described herein, the patterned resist 504 is an optical planarization layer.

[0040] Each resist structure 508 includes a bottom surface 509, a first sidewall 510, a second sidewall 512, and a top surface 514. Each resist structure 508 has a height 515 from the bottom surface 509 to the top surface 514. Each resist structure 508 has a width 522 from the first sidewall 510 to the second sidewall 512. A plurality of gaps 518 are defined by adjacent resist structures 508. Each gap 518 has a linewidth 520 between the first sidewall 510 and the second sidewall 512 of the adjacent resist structure 508. The height 515, linewidth 520, and width 522 are selected to tune the number of steps 110 of the scintillation surface 108 and the linewidth d of the plurality of scintillation device structures 106. For example, increasing the height 515 increases the number of repeating intervals of the etched substrate 101 (or device layer 114) and the resist structures 508, thereby increasing the number of steps 110.

[0041] At operation 402, substrate 101 is exposed to beam 516 at a beam angle θ relative to the surface normal of substrate 101. In one embodiment, which may be combined with other embodiments described herein, the beam angle θ is about 10 degrees to about 80 degrees relative to the surface normal of substrate 101. Beam 516 has a substrate etching chemical or device etching chemical that is selective to the resist material 506, i.e., the exposed portions 517 of substrate 101 or the exposed portions (not shown) of device layer 114 are removed at a higher rate than the resist material 506. After beam 516 etches away the exposed portions of substrate 101, at operation 402 (as described herein)... FIG. 5B As shown), a depth h is formed corresponding to the exposed portion 517 of the blazing device structure 106.

[0042] At operation 403, the substrate 101 is rotated to the second rotation angle defined by the reference line 502. like FIG. 5H As shown. In one embodiment, which can be combined with other embodiments described herein, the pressure plates 214, 314 holding the substrate 101 are rotated to a second rotation angle. In another embodiment that can be combined with other embodiments described herein, the second rotation angle This corresponds to 90° relative to reference line 502. The rotation of substrate 101 is not limited to a rotation angle corresponding to 90°. Instead, it can correspond to any predetermined angle. Due to the masking effect, rotation allows the beam 516 to contact the resist structure 508. In one embodiment that can be combined with other embodiments described herein, throughout method 400, the beam 516 will maintain a beam angle θ relative to the reference planes 218, 318 (i.e., the surface normal s) oriented perpendicular to the substrate 101. A constant beam angle allows for increased production throughput because the beam angle θ will not need to be reconfigured. In one embodiment that can be combined with other embodiments described herein, method 400 herein uses only one angled etching system 200, 300 and requires the resist material 506 to be patterned only once to provide high-volume production capabilities.

[0043] At operation 404, the resist structure is exposed to beam 516 at a beam angle θ. Beam 516 etches one of the first sidewall 510 or the second sidewall 512, corresponding to which sidewall 510, 512 is exposed to beam 516. In embodiments that can be combined with other embodiments described herein, the first sidewall 510 is exposed to beam 516. Beam 516 has a chemical substance corresponding to the resist etching chemical substance, such that ions or electrons will substantially etch only the resist structure 508 during the resist etching process. The resist etching chemical substance is selective for the substrate 101 or device layer 114, i.e., the resist structure 508 is removed at a higher rate than the device layer 114 or substrate 101. After beam 516 etches away the resist structure 508, the width 522 of the resist structure 508 relative to... FIG. 5A and FIG. 5B The width shown is reduced. The line width of 520 between the first and second sidewalls is relative to... FIG. 5A and FIG. 5B The line width shown has increased.

[0044] like FIG. 5C As shown, this forms the first step of a plurality of steps 110. The plurality of steps 110 form a structure as shown in the diagram. FIG. 1B and FIG. 1C The blazing surface 108 is shown. The blazing angle γ is the angle between the blazing surface 108 and the surface parallelism p of the substrate 101. The blazing angle γ can be achieved by increasing or decreasing the etching rate of the beam 516. The blazing angle γ can be adjusted by etching at different rates such that the depth h, linewidth 520, and width 522 are all at predetermined values ​​corresponding to different numbers of steps 110 formed on the blazing surface 108. Therefore, the blazing angle γ can be adjusted, and the blazing device structure 106 (such as the blazing device structure 104) can modulate the light propagating through the optics 100 as needed.

[0045] At operation 405, operations 401-404 are repeated until a predetermined number of steps 110 are formed on the optical device 100 (as shown in FIG. 1B and FIG. 1C In one embodiment, which can be combined with other embodiments described herein, the substrate 101 is rotated to a first rotation angle and the substrate 101 or the device layer 114 is etched with the beam 516 until the resist structures 508 are removed or the line width 520 of the gaps 518 has a predetermined line width. As shown in FIG. 5I The platen 214, 314 on which the substrate 101 is placed is rotated to a second rotation angle As shown in FIG. 5D The depth h of the exposed portions 517 corresponding to the blazed device structures 106 increases relative to the depth h shown in FIGS. 5A-5C As shown in FIG. 5J The platen 214, 314 on which the substrate 101 is placed is rotated to a second rotation angle After the resist structures 508 are etched away by the beam 516, the width 522 of the resist structures 508 decreases relative to the width shown in FIGS. 5A-5D The line width 520 between the first sidewall 510 and the second sidewall 512 increases relative to the line width 520 shown in FIGS. 5A-5D At optional operation 406, residual resist material 506 disposed on the device layer 114 or the substrate 101 is removed. Although only four resist structures 508 and three gaps 518 are illustrated, the entire patterned resist 504 can be etched such that a desired number of blazed device structures 106 are formed according to a predetermined design of the optical device 100.

[0046] In summary, a method of forming optical device structures is described herein. The method utilizes rotation of a substrate to form blazed optical device structures on the substrate and the tunability of the etch rate of one of a patterned resist disposed above the substrate and the device layer or the substrate to form blazed optical device structures without the need for multiple lithographic patterning steps and angled etching steps. A constant beam angle allows for increased production because the beam angle Θ will not need to be reconfigured. Only one angled etching system can be used and the resist material will only need to be patterned once to provide high volume production capabilities.

[0047] While the foregoing is directed to implementations of the present disclosure, other and further implementations of the disclosure can be devised without departing from the basic scope thereof, and the scope of the present disclosure is determined by the claims that follow.

Claims

1. A method of forming a blazed optical device structure, comprising the steps of: positioning a substrate at a first rotation angle φ1 in a beam path, the beam configured to be projected to a surface of the substrate at a beam angle Θ relative to a surface normal of the substrate, the substrate having a patterned resist formed thereover, the patterned resist comprising: two or more resist structures, each of the resist structures having a width; and one or more gaps, each of the gaps defined by adjacent resist structures and having a line width defined by the adjacent resist structures; etching the substrate positioned at the first rotation φ1 with the beam; rotating the substrate to a second rotation angle φ2 and etching sidewalls of the resist structures oriented toward the beam such that the width of the resist structures decreases and the line width of the gaps increases; rotating the substrate to the first rotation angle φ1 and etching the substrate positioned at the first rotation angle φ1 with the beam; and forming two or more optical device structures in the substrate, the step of forming the optical device structures comprising the steps of: repeatedly rotating the substrate to the second rotation angle φ2 and etching sidewalls of the resist structures with the beam, and rotating the substrate to the first rotation angle φ1 and etching the substrate with the beam until the resist structures are removed or the line width of the gaps has a predetermined line width.

2. The method of claim 1, wherein the step of etching the substrate at the first rotation angle φ1 comprises the steps of: generating the beam with a substrate etch chemistry that etches the substrate at a greater rate than the patterned resist.

3. The method of claim 1, wherein the step of etching the sidewalls of the resist structure comprises the steps of: generating the beam with a resist etch chemistry that etches the patterned resist at a greater rate than the substrate.

4. The method of claim 1, wherein the first rotation angle φ1 is 0°.

5. The method of claim 1, wherein the second rotation angle φ2 is 90°.

6. The method of claim 1, wherein the beam angle Θ is 10° to 80°.

7. The method of claim 1, wherein the resist structures comprise a photo- sensitive, imprintable, optical planarization, or hardmask material.

8. The method of claim 1, wherein the optical device structures comprise at least 32 steps.

9. The method of claim 1, wherein the beam is a strip beam, a point beam, or a full substrate size beam.

10. The method of claim 1, wherein the beam is an ion beam or an electron beam.

11. A method of forming a blazed optical device structure, comprising the steps of: positioning a substrate at a first rotation angle φ1 in a beam path, the beam configured to be projected to a surface of the substrate at a beam angle Θ relative to a surface normal of the substrate, the substrate having a device layer disposed thereover and a patterned resist formed on the device layer, the patterned resist comprising: two or more resist structures, each of the resist structures having a width; and one or more gaps, each of the gaps defined by adjacent resist structures and having a line width defined by the adjacent resist structures; one or more gaps, each of the gaps defined by adjacent resist structures and having a line width defined by the adjacent resist structures; etching the device layer of the substrate positioned at the first angle of rotation φ1 with the beam; rotating the substrate to a second angle of rotation φ2 and etching sidewalls of the resist structures oriented toward the beam such that the width of the resist structures decreases and the line width of the gaps increases; rotating the substrate to the first angle of rotation φ1 and etching the device layer at the first angle of rotation φ1 with the beam; and forming two or more optical device structures in the device layer, the steps of forming the optical device structures comprising the steps of: repeatedly rotating the substrate to the second angle of rotation φ2 and etching sidewalls of the resist structures with the beam, and rotating the substrate to the first angle of rotation φ1 and etching the device layer with the beam until the resist structures are removed or the line width of the gaps has a predetermined line width.

12. The method of claim 11, wherein the step of etching the device layer comprises the steps of: The beam is generated with a device material etch chemistry that etches the device layer at a higher rate than etching the patterned resist.

13. The method of claim 12, wherein the device material has an etch selectivity of 5: 1 or greater relative to the patterned resist.

14. An augmented reality waveguide combiner fabricated using the method of claim 1 or 11, comprising: an optical device substrate; and a grating disposed in or on the optical device substrate, the grating having a plurality of blazed device structures, each blazed device structure of the plurality of blazed device structures comprising a blazed surface having: at least 16 steps; a facet normal of each of the steps parallel to the surface of the optical device substrate; and a blaze angle defined by the blazed surface and the facet normal.

15. The augmented reality waveguide combiner of claim 14, wherein the blaze angle of two blazed device structures of the plurality of blazed device structures is different.

16. The augmented reality waveguide combiner of claim 14, wherein the blaze angle of two blazed device structures of the plurality of blazed device structures is the same.

17. The augmented reality waveguide combiner of claim 14, wherein two blazed device structures of the plurality of blazed device structures have different depths.

18. The augmented reality waveguide combiner of claim 14, wherein the grating comprises one or more of: a material containing silicon oxycarbide, a material containing titanium dioxide, a material containing silicon dioxide, a material containing vanadium oxide, a material containing aluminum oxide, a material containing aluminum-doped zinc oxide, a material containing indium tin oxide, a material containing tin dioxide, a material containing zinc oxide, a material containing tantalum pentoxide, a material containing silicon nitride, a material containing zirconium dioxide, a material containing niobium oxide, a material containing cadmium stannate, or a material containing silicon carbonitride. ​ 19. The augmented reality waveguide combiner of claim 14, wherein the optical device substrate comprises a non-amorphous dielectric, a crystalline dielectric, silicon oxide, a polymer, or a combination thereof.

20. The augmented reality waveguide combiner of claim 14, wherein the optical device substrate comprises silicon (Si), silicon dioxide (Si02), germanium (Ge), silicon germanium (SiGe), sapphire, or a combination thereof.

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