Multilayer optical element using primary bonding and permanent bonding

Abstract

Systems and methods for forming optical devices including stacked optical element layers using silicon wafers, glass, or devices as substrates. Optical elements can be fabricated on temporary or permanent substrates. In some embodiments, optical devices are fabricated that include a transparent substrate or device, including a charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) image sensor, a light-emitting diode (LED), a micro LED (μLED) display, an organic light-emitting diode (OLED), or a vertical cavity surface-emitting laser (VCSEL). The optical elements can have an intermediate layer formed between optical element layers, and the intermediate layer can be within a thickness range of 1 nm to 3 nm.

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to optical devices, and systems and methods for manufacturing optical element devices.

Background Art

[0002]

[0002] Novel optical devices including metasurfaces can be patterned on one or both sides of a transparent substrate, enabling many optical device possibilities. However, traditional processing techniques, including photolithography, require a glass substrate of minimal thickness, and for most of the optical devices of interest, these thickness limitations are not commercially feasible. The minimum source thickness of the substrate limits the processing options for later thinning the substrate when manufacturing an optical device having elements on both the front and back surfaces of the substrate.

[0003]

[0003] There are many concerns to address in manufacturing novel optical devices on glass substrates, including metal contamination from the substrate to the lithography tool chuck, breakage during handling, glass transparency, metrology performance in the lithography tool, and other factors. In various optical applications, multiple layers of optical elements are used within an optical device to correct for aberrations. Using multiple optical element layers may include patterning on the back surface of a glass substrate to create a doublet. It may be performed to couple this doublet to another glass substrate to create a triplet or the like. These are processes that are difficult to perform cost-effectively and without damaging the nano-scale features.

[0004]

[0004] Further challenges in manufacturing optical devices include manufacturing a buffer layer with a thickness up to several millimeters between optical elements. Conventional methods of manufacturing optical elements and structures may face manufacturing challenges, including pattern alignment that can make manufacturing these dual-sided optical elements difficult.

[0005]

[0005] Accordingly, there is still a need for an improved optical system and method, and a method of manufacturing an improved optical system.

SUMMARY OF THE INVENTION

[0006]

[0006] Embodiments of the present disclosure broadly relate to an optical device including an optical element layer, and a method of forming the optical device. In one example, a method of forming an optical device includes: (a) forming a pattern including a plurality of islands separated by a plurality of trenches in a target layer on a first substrate; (b) forming a low refractive index material on the patterned target layer and within the plurality of trenches formed in the patterned target layer to form a first optical device. The method may further include (c) forming a stack of optical element layers on the first optical device by repeating (a) and (b) in a plurality of iterations.

[0007]

[0007] In another example, a method of manufacturing an optical element includes forming a first pattern in a first target layer formed on a first substrate, and forming a second pattern in a second target layer formed on a second substrate. The first pattern is then bonded to a first surface of a third substrate formed from a transparent material and having a thickness of from about 10 μm to 3 mm. The method further includes bonding the second pattern to a second surface of the third substrate, decoupling the first substrate from the first pattern, and decoupling the second substrate from the second pattern.

[0008]

[0008] In another embodiment, a method of forming an optical element includes forming a first pattern by imprinting a first target layer at a first location using a first pattern master, the first target layer being formed on a first surface of a transparent substrate, the transparent substrate having a thickness of from about 10 μm to about 3 mm. The method further includes forming a second pattern by imprinting a second pattern on a second location on a second target layer formed on a second surface of the transparent substrate using a second pattern master. Forming the second pattern at the second location includes identifying the second location relative to the first pattern and aligning the second pattern master with the second location.

[0009]

[0009] To gain a more detailed understanding of the features of the present disclosure described above, a more specific description of the present disclosure briefly summarized above can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that since the present disclosure may admit other equally effective embodiments, the accompanying drawings show only typical embodiments of the present disclosure and should not be regarded as limiting the scope of the present invention.

Brief Description of the Drawings

[0010]

Figure 1

[0010] It is a flowchart of a method of manufacturing an optical device according to an embodiment of the present disclosure.

Figure 2A

[0011] FIGS. 2A-2I are a series of partial schematic cross-sectional views of an optical element structure formed during the manufacture of an optical device according to an embodiment of the present disclosure.

Figure 2B

Figure 2C

Figure 2D

Figure 2E

Figure 2F

Figure 2G

Figure 2H

Figure 2I

Figure 3

[0012] It is a partial schematic view of a cross - section of an optical element structure according to an embodiment of the present disclosure.

Figure 4

[0013] It is a flowchart of a method for manufacturing an optical element according to an embodiment of the present disclosure.

Figure 5A

[0014] Figures 5A - 5F are a series of partial schematic views of a cross - section of an optical element structure and optical element manufacturing according to an embodiment of the present disclosure.

Figure 5B

Figure 5C

Figure 5D

Figure 5E

Figure 5F

Figure 6A

[0015] Figures 6A to 6C are schematic exemplary top views of an optical element structure according to an embodiment of the present disclosure.

Figure 6B

Figure 6C

Figure 7A

[0016] Figures 7A to 7C are schematic views of a bonding method during optical device manufacturing according to an embodiment of the present disclosure.

Figure 7B

Figure 7C

Figure 8A

[0017] Figures 8A to 8B are schematic views of an optical element structure according to an embodiment of the present disclosure.

Figure 8B

Figure 9

[0018] A schematic view of an optical element structure formed on a device according to an embodiment of the present disclosure.

Figure 10

[0019] A flowchart of a method for manufacturing an optical element according to an embodiment of the present disclosure.

Figure 11A

[0020] Figures 11A to 11D are cross-sectional views of an optical element structure described in conjunction with the steps of a method for manufacturing an optical element according to an embodiment of the present disclosure.

Figure 11B

Figure 11C

Figure 11D

Figure 12

[0021] It is a flowchart of a method for manufacturing an optical element according to an embodiment of the present disclosure.

Figure 13A

[0022] Figures 13A to 13E are cross-sectional views of an optical element structure described in conjunction with the steps of a method for manufacturing an optical element according to an embodiment of the present disclosure.

Figure 13B

Figure 13C

Figure 13D

Figure 13E

Figure 14

[0023] It is a flowchart of a method for manufacturing an optical element according to an embodiment of the present disclosure.

Figure 15A

[0024] Figures 15A to 15D are cross-sectional views of an optical element structure described in conjunction with the steps of a method for manufacturing an optical element according to an embodiment of the present disclosure.

Figure 15B

Figure 15C

Figure 15D

DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0025] Where possible, the same reference numbers have been used to indicate identical elements common to the drawings. Elements disclosed in one embodiment are assumed to be beneficially usable in other embodiments without specific description.

[0012]

[0026] The systems and methods described herein may include the mass production of optical devices, including a double-sided / layered optical element layer. As described herein, an "optical device" is a device configured to have a predetermined effect on light introduced therein. The optical device may include one or more optical element layers. An "optical element layer" may include one or more optical elements, which may or may not have an encapsulation (filling) material formed thereon. The optical element layer described herein includes positive features that can be referred to herein as islands. Each island of the optical element layer is separated from an adjacent island by a negative feature called a trench herein. In some embodiments, the trench can be filled with a filling material. Depending on the embodiment, the islands and trenches may be formed from either a high refractive index material or a low refractive index material. The islands and trenches may have various top-view and cross-sectional dimensions, including polygonal, rounded, tapered, and combined shape dimensions. The islands, and thus the trenches, can be arranged in an aligned array, a random array, a patterned array, or a combination thereof in a top-down view. The optical element includes a single island feature or trench feature that individually contributes to the optical response of the light introduced into the optical device.

[0013]

[0027] The optical devices contemplated herein may include lenses, dot projectors or holographic projectors, color filters, and collimators, as well as their elements and components. In some embodiments, the optical devices described herein may be implemented within an augmented reality device. To fabricate high-bandwidth elements and other optical devices for short-wavelength light, the nano-sized optical elements within the optical element layer may have a maximum dimension, for example, of less than about 100 nm. These structures can be patterned using alternative patterning methods. In some embodiments, nanoimprint (NIL) or EUV lithography may be employed. In one embodiment, nanoimprint lithography can be employed to imprint a hard mask and then directly etch features based on the hard mask imprint without performing hard mask etching. Further, nanoimprint lithography may be employed to directly form the optical element layer on a substrate. The systems and methods described herein enable the consistent formation of both high aspect ratio features having an aspect ratio of 20:1 or greater and low aspect ratio features having an aspect ratio, for example, from 1:1 to 1:3.

[0014]

[0028] In one embodiment, the optical device is manufactured without using a glass substrate. In another embodiment, the optical device is manufactured to not include a glass substrate. In one embodiment, a target layer formed on a silicon (Si) substrate is patterned and subsequently transferred to a device or a transparent substrate. As described herein, the transparent substrate is a substrate that is optically transparent in a predetermined wavelength region in which the optical device is intended to operate. The target layer may be a low refractive index material or a high refractive index material, depending on the embodiment. The target layer may be a single layer or may include one or more laminates of the same composition or various compositions. The method herein may further include, when dicing is performed, directly stacking the patterned target layer onto the completed device while still on the original substrate prior to dicing. For example, the optical element layer can be directly stacked on the substrate of a completed charge-coupled device (CCD), or a complementary metal-oxide semiconductor (CMOS) image sensor, a light-emitting diode (LED), a micro-LED (uLED) display, an organic light-emitting diode (OLED), or a vertical cavity surface-emitting laser (VCSEL), or on another substrate. The method described herein is a form of integrated processing.

[0015]

[0029] In one embodiment, the optical device described herein is formed to include a filling layer. The filling layer is formed between the optical elements of the optical element layer. The filling layer may include an intermediate layer that is a part of the filling layer formed between and on the optical element layers to form a space between the optical element layers of the stacked optical element layer. The filling layer can be designed for specific functions related to various wavelengths. Accordingly, the optical element layer described herein can be configured as an independent optical element layer or a bidirectional optical element layer. Nanoimprint lithography can be employed to directly imprint a pattern of features onto a substrate, and then the filling material is subsequently deposited in a manner that can include forming a material between the elements (optical elements) by inkjet, slot die, spin coating, or other methods, resulting in an inexpensive process. In an alternative embodiment, CVD, PVD, or ALD can be employed to form the optical element layer and / or the filling layer described herein. The shape of the optical elements within the optical element layer of the optical device described herein can range from simple shape dimensions such as circular, triangular, or polygonal to complex shapes that can be combinations of various shape dimensions.

[0016]

[0030] In another embodiment, the optical device may be manufactured by imprinting a negative tone of the target layer of the functional device. The negative tone is a pattern including islands and trenches formed in the target layer, and the target layer may be a low refractive index material. Then, the trench filling material can be formed by atomic layer deposition (ALD) or chemical vapor deposition (CVD). When using a low refractive index material for the target layer, a trench filling material such as amorphous silicon (a-Si), SiN, TiO2, gallium phosphide, or other materials can be deposited in and / or on the trenches to form the optical elements of the optical element layer. In one embodiment, a-Si or SiN may be used in the optical wavelength band near the IR region, and TiO2 may be used in the optical wavelength band near the visible light region. The trench filling material can be formed by spin-on, CVD, or ALD. Subsequently, another layer of a low refractive index material such as silicon dioxide, doped silicon dioxide, fluorinated polymer, or other suitable porous material can be formed on the filled layer. This layer of low refractive index material can act as an intermediate layer to separate the optical element layer (high refractive index material layer) instead of an additional transparent substrate.

[0017]

[0031] In some embodiments, the low refractive index materials described herein are self-planarizing materials and are partially selected for that characteristic. This is because in some embodiments, a planar surface is used in the manufacture of the optical element. In other embodiments, chemical mechanical planarization (CMP) can be used to achieve a predetermined flatness of one or more layers including the low refractive index layer. The flatness may be within a tolerance of 1 nm to 5 nm. In some embodiments, the flatness tolerance is 2 nm. In other embodiments, the flatness tolerance may be less than 1 nm or greater than 5 nm depending on the optical device being manufactured.

[0018]

[0032] In other embodiments, the two-sided optical device is formed on a transparent substrate that separates the optical elements within adjacent optical element layers. The transparent substrate may have a thickness from 10 μm to 3 mm or more. In this embodiment, two target layers are formed on separate temporary substrates. Each target layer is patterned, and the patterning can occur continuously or simultaneously or in an overlapping manner. Depending on the embodiment, each target layer may be a low refractive index material or a high refractive index material. Each patterned target layer may optionally be filled. Each patterned target layer is bonded to a third substrate. The third substrate may be a transparent substrate and acts as an intermediate layer separating the two patterned target layers. The patterned target layers may subsequently be debonded (removed from the bond) from each respective temporary substrate. In one embodiment, a pattern master can be formed to create a pattern in one or both of the target layers. For patterning, an imprint master can be used to directly imprint the target layer and / or the hard mask. In one example, a first pattern master is used to form a first pattern in a first target layer, and a second pattern master is used to form a second pattern in a second target layer.

[0019]

[0033] In another example, the target layer on the substrate is patterned on a single surface using nanoimprint lithography (NIL). The pattern formed in the target layer may be filled with a filling material, bonded to a second substrate, and then separated from the original substrate. In another example, a first target layer on a first substrate and a second target layer on a second substrate are patterned. The first substrate and the second substrate are bonded together to form a layer having a thickness from 10 μm to 3 mm or more. The first substrate and the second substrate may have the same thickness or different thicknesses. Depending on the embodiment, the target layer may be patterned by extreme ultraviolet lithography (EUVL), nanoimprint lithography (NIL), and / or etching.

[0020]

[0034] FIG. 1 is a flowchart of a method 100 for manufacturing an optical device according to an embodiment of the present disclosure. In one embodiment, method 100 is a batch process that includes a plurality of substrates that are manufactured simultaneously. In step 102, a first layer, which may be a protective layer and / or a release layer, is formed on a first substrate such as a Si substrate or another substrate such as a polymer or another material that may be transparent within a predetermined wavelength range. In one example of method 100, glass is not used as the substrate. In one example, the substrate is a finished device such as a CCD, CMOS, VCSEL, LED, or other structure that can act as a substrate on which the optical devices described herein can be directly manufactured. That is, there may be in-situ manufacturing of the optical devices described herein, which is described in more detail in methods 100 and 400 of FIGS. 1 and 4. The first layer formed in step 102 may be a protective layer formed from SiN, SiO2, or may be a release layer formed from a high-temperature adhesive. In one embodiment, the high-temperature adhesive used can withstand temperatures up to about 280 degrees Celsius. In some examples, the first layer formed in step 102 is a combination of a protective layer formed on the substrate and a release layer formed on the protective layer.

[0021]

[0035] In step 104, a first target layer is formed on the release layer. As described herein, the target layer may be a low refractive index material or a high refractive index material that is patterned through various processes. The first target layer may be formed from a-Si, SiN, TiO2, gallium phosphide, or other (one or more) materials suitable for the formation of a plurality of optical elements. In step 106, the layer formed in step 104 is patterned (etched) through a wet or dry etching process to form a plurality of trenches, exposing the release layer formed in step 102. After patterning the first target layer in step 106, in step 108, a plurality of low refractive index materials are formed on the patterned first target layer via CVD, ALD, PVD, or a spin-on process. Further, in one embodiment, in step 108, CMP is used to achieve a predetermined flatness that may be from 1 nm to 5 nm across the layer surface.

[0022]

[0036] The plurality of low refractive index materials that may be employed in process 108 may be formed from silicon dioxide, doped silicon dioxide, fluorinated polymers, nanoparticle films, or porous materials. The low refractive index materials are described herein in contrast to “high” refractive index materials (e.g., amorphous silicon and crystalline silicon, silicon nitride, titanium dioxide, gallium phosphide, tantalum pentoxide, gallium nitride, sulfur-containing materials, polymers, and other materials having suitable optical properties). It should be noted that materials and combinations of materials can be used to form the fill layers and / or optical element layers described herein, and these materials can be selected based on the targeted optical properties of the (one or more) optical devices manufactured by method 100.

[0023]

[0037] The (one or more) low refractive index materials formed in process 108 are formed over the target layer and within trenches formed between islands of the target layer, as shown below in FIGS. 2A - 2I. The top surface of the low refractive index material may be parallel to the substrate. This layer may be of various thicknesses up to about 10 microns or more. Processes 104 - 108 may be employed to form a single optical element layer. In other embodiments, processes 104 - 108 may be repeated in a plurality of iterations (cycles) that may employ the same or different materials, heights, and patterns. Depending on the embodiment, the stacked optical element layers may be formed from the same or different materials. This cycle (of processes 104 - 108) can be repeated from 2 to 100 times to form a plurality of stacked optical element layers.

[0024]

[0038] In one embodiment, a low refractive index material can be used for the filling layer, and the low refractive index material may act to encapsulate the optical elements of the optical element layer. The filling layer is an intermediate layer and may be formed to include an intermediate layer that extends above the top surface of the optical elements of the first optical element layer and separates the optical elements of the first optical element layer from the optical elements of the second optical element layer. Thus, the optical elements of different optical element layers do not contact each other. The lower the refractive index of the material used for filling / encapsulation, the lower the aspect ratio of the constituent nanostructures (patterned features) for each optical element. In one embodiment, the lower aspect ratio results in thinner optical element layers and faster and cleaner etching. Thus, the systems and methods herein provide a more efficient manufacturing process in terms of time, cost, and complexity. In another example, when the filling material has a high refractive index, the height of the optical elements, and thus the height of the optical element layer, increases.

[0025]

[0039] After forming a predetermined number of optical element layers via steps 104-108, in step 110, an optical element structure having one or more optical element layers is formed. As described herein, the optical element structure is a structure formed during various steps of manufacturing an optical device. The optical element structure may be the final optical device or may be further processed via thermal, mechanical, or thermo-mechanical processes. In one example, after forming the optical element structure in step 110, one or more processes may occur in step 112. These steps in 112 may vary depending on whether a release and / or protective layer is used in the manufacture, as well as in the end use of the optical device.

[0026]

[0040] In one embodiment, in step 112A, the second substrate may be bonded to the low refractive index layer on the side opposite the first substrate. Subsequently, in step 112B, the first substrate is removed. The removal in step 112B may be performed by etching, grinding, polishing, heat or other processes, or a combination of processes designed to heat the adhesive release layer above a predetermined temperature. In step 112C, the optical element structure may be further processed to include dicing and / or bonding to the secondary structure. This secondary structure may include a transparent substrate or a device such as a CCD, CMOS, VCSEL, LED, or other structure. In various embodiments, one or more processes in step 112 may include directly stacking two or more optical element layers on the completed device while the optical element layer remains bonded to the substrate from step 102.

[0027]

[0041] In another embodiment, steps 104-110 may be performed on one or more target layers formed on a completed device, such as a CCD, CMOS, VCSEL, LED, or other device acting as a substrate. In this embodiment, one or more optical element layers are formed in situ on the device substrate. In this embodiment, in step 112, further steps such as dicing can be performed. In one embodiment where there is no release layer used, there is no removal of the first substrate via release. In various embodiments, the optical element layer may be permanently bonded to a permanent transparent substrate. The permanent transparent substrate may be formed from glass, polymer, or other materials suitable for various applications. The assembly can then be diced into smaller optical devices. Each optical device can be attached to a final device or bonded as a wafer or sheet to an array of devices on a wafer or sheet. For example, the optical element layer may be stacked on a completed CCD device, CMOS image sensor, or VCSEL substrate in what may be referred to as "integrated processing". In one embodiment, until both the release layer and the first substrate are removed from the optical element structure, the first substrate is removed via a thermal process that melts or degrades the release layer. For example, if a release material having heat resistance up to 280 degrees Celsius is employed, the substrate can be removed by heating the optical element structure above about 280 degrees Celsius to remove the substrate.

[0028]

[0042] Figures 2A - 2I are a series of partial schematic cross - sectional views of an optical element structure formed during the manufacture of an optical device according to an embodiment of the present disclosure. Figure 2A shows a first substrate 202. In one example, the first substrate 202 may be referred to as a temporary substrate and may be formed of Si. In an alternative embodiment, the first substrate 202 may be a completed device such as a CCD, CMOS, VCSEL, LED, or other device structure as required. The first substrate 202 may be bonded to a first target layer 206 via a release layer 204. In one example where the first substrate 202 is a completed device, since the completed device is a permanent substrate, the release layer 204 may not be employed. In one embodiment, glass is not used as the first substrate 202. In one embodiment, the release layer 204 may be a single layer of a high - temperature adhesive or a protective dielectric layer.

[0029]

[0043] In other embodiments, as shown in the inset of Figure 2A (Figure 2A - 1), the substrate includes a release intermediate layer 204A on the first substrate 202 and a barrier intermediate layer 204B on the opposite side of the substrate from the release layer. When the release intermediate layer 204A or 204 is used as a single layer, it can include a paste or other adhesive configured to withstand temperatures up to about 280 degrees Celsius and has a thickness of 1 nm to 100 nm. In another example, although not shown here, the release layer 204 may include only a dielectric layer of SiO2 or SiN with a thickness of 1 nm to 100 nm and is formed by PVD, CVD, or other deposition processes. In other examples, the release layer 204 may have a thickness greater than 100 nm. In one embodiment, Figure 2A may correspond to step 102 of Figure 1. The first target layer 206 may include various materials described herein, such as a - Si, SiN, TiO2, or gallium phosphide.

[0030]

[0044] Figure 2B shows the device of Figure 2A and further includes a patterned (etched) first target layer 206. The first target layer 206 is patterned to have a plurality of negative (concave) features called a plurality of trenches 208A and a plurality of positive (convex) features called a plurality of islands 208B. In one embodiment, Figure 2B shows the optical element structure resulting from step 106 of Figure 1. Each island of the plurality of islands 208B may have a width 208C measured parallel to the first substrate 202. In one example, the width 208C of each island of the plurality of islands 208B may vary within the optical element layer. The optical element is shown herein as having a cross-section that is approximately square or rectangular in shape, but it should be noted that in other embodiments, the optical element may include tapered sidewalls and thus form a trapezoidal cross-section (not shown).

[0031]

[0045] Figure 2C shows an optical element structure including a first low refractive index layer 208. The first low refractive index layer 208 is formed covering the top surface 206A of the island 208B and is formed between the islands 208B, for example, within the trench 208A. In one embodiment, the first low refractive index layer 208 extends a distance 210 above the top surface 206A of the first target layer 206. The distance 210 is the thickness (T) of the first low refractive index layer 208 208) portion. Therefore, the first low refractive index layer 208 may include an intermediate layer. This is because the distance 210 acts to separate the first target layer 206 (e.g., an optical element layer) from the subsequently stacked optical element layers. The structure of FIG. 2C may be the same as that formed in step 108 of FIG. 1 and can be referred to as the first optical element layer 222. As described above, the distance 210 may include an intermediate layer. This is because this distance separates the first optical element layer 222 from the subsequently formed optical element layers. The filling material 210 can be adjusted to various distances between and among the optical element layers (e.g., via the type and / or thickness of the material) to produce the desired effects for embodiments of single or multiple (doublet, triplet, or more) optical devices. The first optical element layer 222 can be referred to as a singlet.

[0032]

[0046] FIGS. 2D to 2G show examples of the repetition of the cycles of steps 104 to 108 of FIG. 1. In one embodiment, FIG. 2D shows a second target layer 212 formed on the filling material 210. FIG. 2E shows a plurality of trenches 216A and a plurality of islands 216B formed in the second target layer 212 according to the patterning. In FIG. 2F, a second low refractive index material forms a second low refractive index layer 214 formed in a manner similar to the first low refractive index layer 208. The structure formed by the second low refractive index layer 214 and the second target layer 212 can be referred to as the second optical element layer 224. The second low refractive index layer 214 may be formed to extend a distance 214A beyond the top 212A of the second target layer 212. In one embodiment, two different materials may be employed for each of the first target layer 206 and the second target layer 212.

[0033]

[0047] In some embodiments that can be combined with other embodiments and configurations of this specification, various materials may be employed for each of the first low refractive index layer 208 and the second low refractive index layer 214. In one embodiment, the first optical element layer 222 may be configured for a first wavelength or a range of first wavelengths, and the second optical element layer 224 may be configured for a second wavelength or a range of second wavelengths. The first target layer 206 and the second target layer 212 may include the same or different patterns. The first target layer 206 and the second target layer 212 may each have the same or different pattern characteristics, including height (thickness), spacing, and material type, depending on the embodiment. The combination of the first optical element layer 222 and the second optical element layer 224 may be referred to as a doublet.

[0034]

[0048] In one embodiment, two different materials may be employed for each of the first target layer 206 and the second target layer 212. In another embodiment that can be combined with other embodiments of this specification, two different materials may be employed for each of the first low refractive index layer 208 and the second low refractive index layer 214. In another embodiment, the same material may be employed for each of the first target layer 206 and the second target layer 212. In another embodiment that can be combined with other embodiments and configurations of this specification, the same material may be employed for each of the first low refractive index layer 208 and the second low refractive index layer 214. Each of the first low refractive index layer 208 and the second low refractive index layer 214 has a thickness T 208 , T 214It has. The thickness of each of the first low refractive index layer 208 and the second low refractive index layer 214 includes the distance that each low refractive index layer extends beyond the top surface of the optical element. For example, the first low refractive index layer 208 and the second low refractive index layer 214 each extend from the respective top surfaces 206A and 212A by distances 210 and 214A, which may be the same or different distances. Accordingly, each of the first optical element layer 222 and the second optical element layer 224 may have a different height. In another embodiment, each of the first optical element layer 222 and the second optical element layer 224 may have the same height depending on the embodiment. The extension of each filling layer beyond the optical element may be employed as an intermediate layer instead of a glass substrate or instead of an additional layer of another material.

[0035]

[0049] FIG. 2G shows a third optical element layer 226 formed from a third target layer 216 and a third low refractive index layer 218. The third low refractive index layer 218 may be formed from the same or different materials as the target layer and the low refractive index layer used in other optical element layers such as the first optical element layer 222 and the second optical element layer 224. The third low refractive index layer 218 has a thickness T that includes a distance 218A by which the third low refractive index layer 218 extends beyond the third target layer 216 218It has. The distance 218A may be the same as or different from the distances 210 and 214A, and the optical element layers 222, 224, and 226 may be configured using various thicknesses and thickness ratios. For example, ratios such as the thickness of the optical element layer: the thickness of the low refractive index layer, or dimensions between and among the optical element layers, or dimensions between and among the filling layers, etc., produce the desired effect. In one embodiment, each of the distances 210, 214A, and 218A may be, for example, from about 1 micron to about 50 microns when the optical element layers 222, 224, and / or 226 are configured to interact optically, and in some embodiments, it may be from 50 nm to 2 microns. The combination of the first optical element layer 222, the second optical element layer 224, and the third optical element layer 226 may be referred to as a triplet. In one example, at least one of the distances 210, 214A, and 218A is less than 1 micron, and in other examples, at least one of those distances may be from about 50 nm to about 300 nm.

[0036]

[0050] Figures 2G to 2I show three optical element layers 222, 224, and 226, but it should be noted that in various embodiments, a single optical element layer as shown in Figure 2C or a double optical element layer as shown in Figure 2F may be employed. In other examples, four or more optical element layers can be stacked to form an optical device. In one embodiment, T 208 , T 214 , and T 218 may each be from about 100 nm to about 2 microns. In one embodiment, the overall thickness T overall shown in Figure 2G of the optical device, which can include one or more stacked optical element layers, may be from a thickness of about 1 micron to a thickness of about 2000 microns or more. In one embodiment, a color filter or an interference filter or other optical filter layer may be formed on the optical element layer stack, for example, on one or more optical element layers such as the first optical element layer 222, the second optical element layer 224, or the third optical element layer 226, depending on the number of optical element layers employed in the exemplary embodiment.

[0037]

[0051] FIG. 2G further shows an exemplary spacing 228 between optical elements formed in the first target layer 206. In one embodiment, the spacing 228 between optical elements may vary between and among the optical elements formed in the first target layer 206, as well as between the target layers 206, 212, and 216. In one example, the spacing 228 between elements exceeds one wavelength in the encapsulating material (e.g., the first low refractive index layer 208), in which case the wavelength may be equal to the spacing 228 of about 1 micron. In one example, an IR optical device may be manufactured using a single optical element layer, doublet, or triplet, or a stack thereof. In another example, an RGB optical device may be manufactured using a singlet or doublet optical device. In another embodiment, a white light or other broadband optical device may be manufactured from an optical device including a doublet, triplet, or more than three optical element layers. In some examples, a white light optical device may be manufactured using a single optical element layer.

[0038]

[0052] FIGS. 2H and 2I show a transfer process for a plurality of optical element layers manufactured in accordance with embodiments of the present disclosure. In FIG. 2H, a second substrate 220 is coupled to a third optical element layer 226, which in this example can be referred to as the "topmost" or "outermost" optical element layer. The second substrate 220 may be manufactured from glass, plastic, or other material and may be optically transparent. In FIG. 2I, the first substrate 202 is removed and the optical element structure may subsequently be rotated. In one example, the structure can be rotated by 180 degrees. In another example, the structure can be divided into a plurality of discrete elements. As detailed herein, other subsequent steps can be performed before, after, or without dicing or removing the first substrate 202.

[0039]

[0053] FIG. 3 is a partial schematic view of a cross-section 300 of an optical element structure according to an embodiment of the present disclosure. FIG. 3 shows a first portion 302 that may be the same as that shown in FIGS. 2A-2G, and a second portion 304 that is identical to the first portion 302. FIG. 3 is shown to illustrate an extended pattern that is repeated across the optical element structure and may subsequently be diced (divided). In one embodiment, the width 306 of the first substrate 202 may be such that each diced portion has a maximum diameter of from 1 mm to 4 cm, so that a plurality of individual optical devices can be formed by dicing. In other examples, each diced portion may have a maximum diameter that exceeds 4 cm. The diced optical devices may be formed to be the same size or of various sizes, depending on the embodiment. The optical elements of the optical element layers 206, 212, 216 are shown as having a polygonal shape, but it should be noted that in other examples, the optical elements may have cross-sectional shape dimensions that include rounded, triangular, or polygonal shapes, or combinations thereof. Further, it should be noted that the cross-sectional shape dimensions may be tapered, angled, arcuate, or of various other shape dimensions.

[0040]

[0054] FIG. 4 is a flowchart of a method 400 for manufacturing an optical element according to an embodiment of the present disclosure. In method 400, in step 402, a layer that may be a release layer and / or a protective layer may be formed on a substrate as described above. In step 404, a target layer may be formed on the release layer, and the target layer may be patterned in step 406 to form a plurality of trenches to expose the release layer. The patterning in step 406 may be performed via dry or wet etching or via a nanoimprint process. In step 408, a material such as a-Si, SiN, TiO2, gallium phosphide, or others may be deposited in and over the plurality of trenches of the patterned target layer. In step 410, for example, a plurality of residual materials formed over the top surface of the optical element layer are removed to expose the optical element layer with the trenches filled with the material. In step 412, following the removal of the plurality of residual materials in step 410, a plurality of low refractive index materials are formed on the resulting planar surface. In some examples, in step 412, CMP is used to achieve a predetermined flatness of the low refractive index material.

[0041]

[0055] Steps 406-412 can be employed to form a single optical element layer. In other embodiments, steps 406-412 may be repeated in a plurality of iterations (cycles) to form a stack of optical element layers. Each optical element layer of the stack may have the same or different optical element layer materials, heights, and patterns. If a filling material is included within one or more of the optical element layers of the stack, the filling material used for each filling layer may be the same or different low refractive index materials. This cycle of steps 406-412 can be repeated from 2 to 100 times to form a plurality of optical elements. After forming a predetermined number of optical element layers via steps 406-412, an optical element structure that may include one or more optical element layers is formed in step 414. In step 416, the optical element structure 414 may be further processed. In one embodiment, in step 416A, a second substrate may be bonded to the low refractive index layer on the opposite side of the first substrate, and subsequently, in step 416B, the first substrate is removed. The second substrate may be a transparent substrate or a device such as a CCD, CMOS, VCSEL, LED, OLED, or uLED. In step 416C, the structure may be further processed to include dicing and / or bonding to a secondary structure.

[0042]

[0056] In various embodiments in step 416, which may represent one or more steps, the optical element structure may be permanently bonded to another transparent substrate. Following the bonding, the structure may be diced into smaller elements and individually attached to a final device, or the substrate may be bonded as a wafer or sheet to an array of devices on a wafer or sheet. For example, the optical element layers may be stacked on a substrate of a completed CCD device, CMOS image sensor, or VCEL, or other device. In another embodiment, steps 406-412 may be performed on a completed device such as a CCD, CMOS, VCSEL, LED, or other device, whereby the (one or more) optical element layers are formed in situ on the device. In this embodiment, in step 416, further steps such as dicing may be performed, but a release layer is not used.

[0043]

[0057] FIGS. 5A-5F are a series of schematic diagrams of an alternative method of manufacturing an optical device according to an embodiment of the present disclosure. FIG. 5A shows a substrate 502, which may be a Si wafer, on which a release layer 504 is formed. The release layer 504 may be similar to the release layer 204 of FIG. 2A and may include a barrier layer (not shown). The barrier layer may be a portion of the release layer 504 and may be formed between the adhesive portion of the release layer 504 and the target layer 506. In one example, the target layer 506 may be formed from a low refractive index material. In another example, the substrate 502 may be a CCD, CMOS, VCSEL, LED, or other device suitable for various applications, and the optical element is formed in situ on the substrate 502. The device of FIG. 5A may be formed via the processes 402 and 404 described in FIG. 4.

[0044]

[0058] FIG. 5B shows a target layer 506 formed on the release layer 504. The target layer 506 is etched to form a plurality of trenches 508A and islands 508B as described above in process 406. In FIG. 5C, a first optical element layer 510 may be formed covering the target layer 506 and may be formed between the islands 508B and within the trenches 508A, similar to that described in process 408. The first optical element layer 510, indicated by the distance 512, is removed as shown in FIG. 5D and as described in process 410. FIG. 5D shows the height 526 of the optical element, which may be in the range of about 400 nm to about 1500 nm in some embodiments. In alternative embodiments, the height 526 of the optical element may be from 100 nm to 400 nm, and in other embodiments, the height 526 of the optical element may be from 50 nm to 100 nm. As described herein, the height of the optical element across the optical element layer is the same, creating a flat top surface of the optical element layer.

[0045]

[0059] FIG. 5E shows a second filling layer 514 formed on the first optical element layer 510 after removing a portion of the optical element layer 510 as described in step 410. This step is described at 412 in FIG. 4, and the second filling layer 514 may or may not contain the same composition as the target layer 506. The second filling layer 514 may include an intermediate layer and can adjust, for example, the thickness and composition between and among the optical element layer structures to produce a desired effect. The structure of FIG. 5E may be referred to as the first optical element layer 516. FIG. 5F shows the structure of FIG. 5E having a further second optical element layer 524 formed on the first optical element layer 516. The second optical element layer 524 may be formed in a similar manner as the first optical element layer 516. The second optical element layer 524 includes a second optical element 520 and a third filling layer 518. The third filling layer 518 may be formed from a low refractive index material. Another filling layer 522 is formed on the second optical element 520 and the third filling layer 518. The top surface of the second optical element 520 may be in the same plane as the top surface of the third filling layer 518. In one embodiment, a-Si or SiN may be used in the optical wavelength band near the IR region, and TiO2 may be used in the optical wavelength band near the visible light region.

[0046]

[0060] Figures 6A - 6C are schematic illustrations of top views of an optical element structure according to an embodiment of the present disclosure. Figures 6A - 6C are schematic top - down views of the optical elements showing only the view of the top - most optical element. Thus, the optical element layers positioned within the layers below the optical element laminate may include a configuration different from or the same as that described for the top layer shown in Figures 6A - 6C. Figure 6A shows a first plurality of optical elements 704 formed on a substrate 702. The first plurality of optical elements 704 are shown as having a top - view cross - section that is circular or elliptical in shape. The first plurality of optical elements 704 have a vertical spacing 706 and a horizontal spacing 708. One or both of the vertical spacing 706 and the horizontal spacing 708 may vary between and among the first plurality of optical elements 704 depending on the embodiment. Three rows 710 of optical elements including the first plurality of optical elements 704 are shown in Figure 6A, although various embodiments may include more or fewer rows having various spacings. The rows 710 may be spaced equidistantly or may be spaced at random intervals.

[0047]

[0061] Figure 6B shows a second plurality of optical elements 712 formed on a substrate 702. The second plurality of optical elements 712 are shown as having a top view cross-section that is square or other polygonal in shape. The second plurality of optical elements 712 have a vertical spacing 714 and a horizontal spacing 716 between and among each pair of adjacent optical elements 712 of the plurality of optical elements 712. Each of the vertical spacing 714 and the horizontal spacing 716 may vary depending on the embodiment. Four rows 718 of optical elements are shown in Figure 6B, although various embodiments may include more or fewer rows. The second plurality of optical elements 712 are shown in Figure 6B as being aligned along a common axis for each of the four rows 718, although in alternative embodiments, the alignment occurs along a vertical axis that is in the direction of the vertical spacing 714. In another example, the second plurality of optical elements 712 may be aligned along both a horizontal location (axis) and a vertical location (axis) to form an aligned array (not shown). In an example of an aligned array of optical elements, each optical element of the second plurality of optical elements 712 is equally spaced apart in both the direction of the horizontal spacing 716 and the vertical spacing 714. In various examples, the second plurality of optical elements 712 may have various polygonal or non-polygonal cross-sections and may include sharp edges or rounded edges, or combinations thereof.

[0048]

[0062] Figure 6C shows a third plurality of optical elements 720 formed on a substrate 702, and the third plurality of optical elements 720 have an irregular-shaped top-view cross-section that varies between and among the individual optical elements of the third plurality of optical elements 720. The third plurality of optical elements 720 have a vertical spacing 722 and a horizontal spacing 724 between and among the elements that vary according to the embodiment. In one example, the vertical spacing 722 is non-uniform between and among the third plurality of optical elements 720. In another example, the horizontal spacing 724 is non-uniform between and among the third plurality of optical elements 720. In yet another example, both the vertical spacing 722 and the horizontal spacing 724 of the third plurality of optical elements 720 are non-uniform. Four rows 726 of optical elements are shown in Figure 6C, although various embodiments may include more or fewer rows. Although the third plurality of optical elements 720 are shown in Figure 6C as being aligned along the rows 726, in alternative embodiments, the alignment occurs along a vertical axis in the direction of the vertical spacing 722. In another example, the third plurality of optical elements 720 may be aligned in both horizontal and vertical locations, forming an aligned arrangement (not shown), and each optical element 720 is equally spaced apart in both the horizontal 724 and vertical 722 directions. The shape dimensions employed for the plurality of optical elements, including 708, 712, 720, and others described herein, may be irregular-shaped, as well as triangular-shaped, or other shape dimensions suitable for various embodiments. In some examples, the diameter of the optical elements varies between and among the rows 726. In other examples, the diameter of each optical element 720 in a single row may vary within the range of that row. It should be noted that the top views shown in Figures 6A-6C are exemplary, and other spacings of the optical elements are possible. For example, the spacings of the optical elements described herein may be variable spacings used to generate an aligned arrangement having equally spaced intervals between and among the optical elements, a random arrangement having random intervals, or a patterned arrangement that repeats a regular or irregular interval pattern.

[0049]

[0063] Figures 7A-7C are schematic diagrams of a bonding method for an optical element according to an embodiment of the present disclosure. FIG. 7A shows a first optical element structure 800A including an optical element layer stack 828 of a first optical element layer 802, a second optical element layer 804, and a third optical element layer 806. Each of the optical element layers 802, 804, and 806 includes a plurality of optical elements 812, 816, and 820, respectively. Each optical element layer 802, 804, 806 further includes layers of a low refractive index material 814, 818, and 822 formed on and within trenches between each of the plurality of optical elements 812, 816, and 820. The third optical element layer 806 is formed on a substrate 808. In one example, the third optical element layer 806 has a layer 810 formed between the substrate 808 and the third optical element layer 806. As described herein, the layer 810 may be a protective layer, a release layer, or a combination thereof, and may be formed to have a thickness of 100 nm or more. The optical element layer stack 828 has a top bonding layer 824 formed on the first optical element layer 802. The top bonding layer 824 has a thickness of 20 nm to 100 nm. The second substrate 830 has a second bonding layer 826 formed under the second substrate 830. As described above, the second substrate 830 may be a transparent substrate made of glass, a polymer, or other materials suitable for various applications.

[0050]

[0064] FIG. 7B shows a second optical element structure 800B, where a second substrate 830 is coupled to an optical element layer stack 828. The second substrate 830 is coupled to the optical element layer stack 828 via a top bonding layer 824 and a second bonding layer 826 formed under the second substrate 830. FIG. 7C shows a third optical element structure 800C, which is the structure of the second optical element structure 800B with the substrate 808 removed. In FIGS. 7A - 7C, three optical element layers 802, 804, and 806 are shown, but fewer or more optical element layers may be used depending on the embodiment. The second substrate 830 may be from 100 microns to 500 microns or more. In one example, after the second substrate 830 is coupled to the third optical element structure 800C, the second substrate 830 can be thinned from its original thickness, for example, from 500 microns to 100 microns, using CMP or other methods.

[0051]

[0065] FIGS. 8A - 8B show an optical element structure according to an embodiment of the present disclosure. FIG. 8A shows a first optical element structure 900A before assembly / layering. The first optical element structure 900A includes a first optical element layer 906 formed on a substrate 908. The first optical element layer 906 is coupled via a layer 910 that can be formed of SiO2 or other materials. In other examples, layer 910 may be a bond release layer for a high-temperature resistant adhesive. A second optical element layer 904 is coupled to the first optical element layer 906, and a third optical element layer 902 is coupled to the second optical element layer 904. The second substrate 916 may have a first bonding layer 914 and a second bonding layer 918 formed on both sides. Further, a device 922 has a device bonding layer 920 formed thereunder. The device 922 may include SiO2 with a thickness from 20 nm to 10 μm.

[0052]

[0066] FIG. 8B shows a second optical element structure 900B. The second optical element structure 900B includes the first optical element structure 900A from FIG. 8A. The second optical element structure 900B shows a second substrate 916 coupled to a third optical element layer 902 via a top bonding layer 912 formed on the third optical element layer 902. In the second optical element structure 900B, layers 910 and substrate 908 have been removed, for example, by etching, grinding, polishing, or other methods. Further, devices 922 such as CMOS, CCD, VCSEL, or other devices 922 are coupled to the second substrate 916 via a second bonding layer 918 and a device bonding layer 920, each of which may include SiO2 having a thickness of 1 nm to 100 nm. The second substrate 916 may be 100 microns to 500 microns, and after the second substrate 916 is coupled to the second optical element structure 900B, it may be thinned from its original thickness, for example, from 500 microns to 100 microns, using CMP or other methods.

[0053]

[0067] FIG. 9 is a diagram of the optical element layer laminate 1018. The optical element layer laminate 1018 is coupled to the device 1016. In one embodiment, the assembly 1000 of the optical element layer laminate 1018 is coupled to the device 1016, which can be a CMOS, CCD, VCSEL, or other device. The optical element layer laminate 1018 is formed on a substrate 1008 having a layer 1010 formed between the optical element layer laminate 1018 and the substrate 1008. The layer 1010 may include a release layer or a protective layer or a combination thereof. The optical element layer laminate 1018 is composed of three optical element layers, namely, a first optical element layer 1002, a second optical element layer 1004, and a third optical element layer 1006. It should be noted that in other embodiments, the optical element device may include more or fewer optical element layers than shown. The device 1016 is coupled to the optical element layer laminate 1018 via a first bonding layer 1012 formed on the first optical element layer 1002 and a second bonding layer 1014 formed under the device 1016. As described herein, the optical element layer laminate 1018 may be formed and then coupled to the device 1016. In another embodiment, the optical element layer laminate 1018 may be pre-formed and coupled to the device 1016. In yet another embodiment, the optical element layer laminate 1018 may be formed in situ on the device 1016. In some embodiments not shown herein, a protective layer of a filling material may be formed on the outermost (outermost) optical element layer such as the first optical element layer 1002 of FIG. 9.

[0054]

[0068] FIG. 10 is a flowchart of a method 1100 for manufacturing an optical element according to an embodiment of the present disclosure. FIGS. 11A-11D are cross-sectional views of an optical element structure described in conjunction with the steps of method 1100. In step 1102 shown in FIG. 11A, a first target layer 1202 on a first substrate 1204 is patterned to form a first pattern 1206. The first pattern 1206 includes a plurality of islands 1210. Each pair of adjacent islands among the plurality of islands 1210 is separated by a negative (concave) space that may be referred to as a trench 1208. The first pattern 1206 may be formed by photolithography and etching, or by nanoimprint lithography (NIL) and etching, or by direct imprint (embossing) of the first target layer 1202. In step 1104, the first pattern 1206, particularly the trenches 1208 of the first pattern 1206, may optionally be filled with a low refractive index material (not shown).

[0055]

[0069] In step 1106 shown in FIG. 11B, a second target layer 1212 formed under a second substrate 1222 is patterned to form a second pattern 1214. The second pattern 1214 includes a plurality of islands 1216, and each pair of adjacent islands among the plurality of islands 1216 is separated by a trench 1218. The second pattern 1214 may be formed by optical lithography and etching, or by nanoimprint lithography (NIL) and etching, or by direct imprint of the second target layer 1212. In step 1108, the second pattern 1214, particularly the trench 1218 of the second pattern 1214, may optionally be filled with a low refractive index material (not shown here). In some embodiments, neither the first pattern 1206 nor the second pattern 1214 is filled with a low refractive index material. In some embodiments, the first pattern 1206 is filled with a low refractive index material in step 1104. In other embodiments, the second pattern 1214 is filled with a low refractive index material in step 1108. In further embodiments, the first pattern 1206 and the second pattern 1214 are each filled with a low refractive index material in steps 1104 and 1108, respectively.

[0056]

[0070] FIG. 11C is a diagram of an optical element structure after steps 1110 and 1112. In step 1110, the first pattern 1206 is bonded to a first surface 1220A of a third substrate 1220. The third substrate 1220 may be formed of a transparent material including glass, polymer, diamond, or other materials. Depending on the embodiment, the third substrate 1220 may have a thickness of about 10 μm to 3 mm. In step 1112, the second pattern 1214 is bonded to a second surface 1220B of the third substrate 1220 on the side opposite to the first pattern 1206.

[0057]

[0071] In step 1114, the first substrate 1204 and the second substrate 1222 are removed. Thus, the first substrate 1204 and the second substrate 1222 may each be referred to as a temporary substrate or a carrier substrate. FIG. 11D shows the optical element structure after step 1114. In some embodiments, although not illustrated herein, there may be a layer of bonding material called a release layer, similar to the release layer 204 described above. The release layer may be formed between the first target layer 1202 and the first substrate 1204 and / or between the second target layer 1212 and the second substrate 1222. The release layer may be an adhesive material or a heat-activated material (e.g., dissociates upon heating). In step 1114, the release layer is used to facilitate the peeling of the first pattern 1206 and the second pattern 1214 from the first substrate 1204 and the second substrate 1222, respectively, via thermal, chemical, and / or mechanical means. In step 1116, the optical element structure of FIG. 11D may be further processed, for example, by annealing and / or by adding (stacking) additional optical elements and transparent substrates. In one embodiment, in step 1116, at least steps 1102, 1106, 1110, 1112, and 1114 are repeated in an iterative manner to form additional optical element layers.

[0058]

[0072] FIG. 12 is a flowchart of a method 1300 for manufacturing an optical element according to an embodiment of the present disclosure. FIGS. 13A-13E are cross-sectional views of an optical element structure and are described in conjunction with the steps of method 1300. In step 1302, as shown in FIG. 13A, a first pattern 1402 is formed on a first target layer on a first surface 1404A of a first substrate 1404. The first pattern 1402 includes a plurality of trenches 1408 between islands 1406. The first pattern 1402 may be formed in step 1302 using photolithography and etching, NIL and etching, or direct imprinting.

[0059]

[0073] In step 1304, as shown in FIG. 13B, a plurality of trenches 1408 of the first pattern 1402 are optionally filled with a low refractive index material 1410. The low refractive index material 1410 may be a self-planarizing material, whereby after step 1304, the top of the low refractive index material 1410 is coplanar with the top of the plurality of islands 1406. In step 1306, a second pattern 1412 is formed from a second target layer formed on the first surface 1414A of the second substrate 1414. The second pattern 1412 is shown in FIG. 13C. The second pattern 1412 includes a plurality of trenches 1416. Each trench of the plurality of trenches 1416 is formed between each pair of adjacent island lines 1418. The plurality of trenches 1416 and the plurality of islands 1418 may vary in width, height, and cross-sectional shape. The plurality of islands 1418 are shown with a substantially polygonal cross-section, but their dimensional shapes may take other shapes such as rounded, triangular, or combinations thereof, and may be tapered, angled, or arcuate. The second pattern 1412 may be formed in step 1306 using photolithography and etching, NIL and etching, or direct imprinting.

[0060]

[0074] In operation 1308, as shown in FIG. 13D, the second pattern 1412 may optionally be filled with a low refractive index material 1420. In operation 1310, one or more of the first substrate 1404 and the second substrate 1414 may be planarized. In one embodiment of operation 1310, the second surface 1404B of the first substrate 1404 and the second surface 1414B of the second substrate 1414 are each planarized in one or more sub-operations. Subsequently, in operation 1312, as shown in FIG. 13E, the second surface 1404B of the first substrate 1404 is bonded to the second surface 1414B of the second substrate 1414. Thus, the optional planarization in operation 1310 can facilitate the bonding of the first substrate 1404 to the second substrate 1414 in operation 1312. In operation 1314, further processing of the optical element structure may be performed. The further processing in operation 1314 may include annealing, addition of other optical element structures via stacking, dicing, or other operations.

[0061]

[0075] FIG. 14 is a flowchart of a method 1500 for manufacturing an optical element according to an embodiment of the present disclosure. FIGS. 15A - 15D are cross-sectional views of an optical element structure described in conjunction with method 1500. FIG. 15A is a cross-sectional view of a first transparent substrate 1604. The first transparent substrate 1604 may be formed from glass, polymer, diamond, or other optically transparent material, or a combination of optically transparent materials. A first target layer 1602 is formed on the first surface 1604A of the first transparent substrate 1604. A second target layer 1606 is formed on the second surface 1604B of the first transparent substrate 1604.

[0062]

[0076] In process 1502, a first master pattern is formed. The first master pattern can be used to imprint a pattern onto a target layer on a substrate. The first master pattern may be formed in process 1502 using a rigid material such as silicon or a silicon-containing material, or a less rigid material including a material with a low or high refractive index. The material used to form the first master pattern may be selected based on factors including the composition and material properties of the target layer to be imprinted in process 1504. The first master pattern may be formed in process 1502 by photolithography and etching, by NIL and etching, or by direct imprinting of the first master target layer. Using the first master pattern formed in process 1502, a first pattern 1622 is fabricated in process 1504. The first pattern 1622 is shown in FIG. 15B. The first pattern 1622 includes a plurality of islands 1610 separated by trenches 1608. The plurality of islands 1610 extend from a first surface 1604A of a first transparent substrate 1604. In process 1506, a filling layer (not shown here) may optionally be formed within the trenches 1608. The filling layer may be formed from a low refractive index material.

[0063]

[0077] In process 1508, the second master pattern may be formed from a rigid material such as silicon or a silicon-containing material, or from a less rigid material including a low or high refractive index material. The second master pattern can be used to imprint a target layer on a substrate, and the second master pattern may include a pattern different from the first master pattern. The second master pattern may be formed from various materials depending on the composition of the target layer to be imprinted in process 1510. The second master pattern may be formed in process 1508 by photolithography and etching, NIL and etching, or direct imprinting of the second master target layer. In process 1510, using the first pattern formed in process 1506 as a reference point for alignment, the second pattern master is aligned with the second target layer 1606. In process 1512, the second pattern 1626 is formed in the second target layer 1606. The second pattern 1626 shown in FIG. 15C includes a plurality of islands 1616 extending from the second surface 1604B of the first transparent substrate 1604. The islands 1616 are separated by trenches 1618. In process 1514, a filling layer may optionally be formed within the trenches 1618. The filling layer may be formed from a low refractive index material.

[0064]

[0078] In operation 1516, the optical element structure may undergo further processing. The further processing in operation 1516 may include annealing, addition of other optical element layers via stacking, dicing, or other operations. In one embodiment of operation 1516, as shown in FIG. 15D, at least operations 1504, 1508, 1510, and 1512 may be repeated to form a stack of optical elements. FIG. 15D includes a first transparent substrate 1604, as well as a first pattern 1622 and a second pattern 1626 formed in operations 1504 and 1508. FIG. 15D further includes a second transparent substrate 1620. A first surface 1620A of the second transparent substrate 1620 includes a third pattern 1624. A second surface 1620B of the second transparent substrate 1620 is coupled to a first side 1602A of the first pattern 1622. In some embodiments, the third pattern 1624 may be optionally filled (not shown in FIG. 15D). The third pattern 1624 may be formed from a first master, a second master, or a third master different from the first and second masters.

[0065]

[0079] Thus, the embodiments described herein can be used in various combinations to manufacture stacked optical elements. Two or more optical elements can be manufactured via optical lithography or NIL and etching, and / or by direct imprinting using a pattern master. The optical elements may be manufactured on a temporary substrate. The temporary substrate is coupled to the target layer and later removed after the patterned target layer is coupled to a permanent or carrier (second temporary) substrate. The optical element layers may be separated from each other using a filling layer that includes an intermediate layer. The filling layer may extend a distance of from about 1 nm to about 3 mm to form the intermediate layer of the filling layer beyond the top surface of the underlying optical element layer. In other embodiments, the optical elements may be fabricated on a permanent substrate that is a transparent substrate of various thicknesses up to about 3 mm.

[0066]

[0080] Although various embodiments incorporating the teachings of the present invention have been shown and described in detail herein, those skilled in the art can readily devise many other various embodiments incorporating these teachings.

Claims

**Claim 1** An optical element laminate, comprising: a substrate having a first surface and a second surface, the substrate comprising one of the components of a CCD, a CMOS, a VCSEL, an LED, an OLED, and a μLED, and a first layer formed on the first surface of the substrate, the first layer comprising a plurality of islands separated by a plurality of trenches and a filling material provided in the plurality of trenches, and consisting of an optical element layer, wherein the height of the plurality of islands is equal to the height of the filling material, the optical element laminate. **Claim 2** The optical element laminate according to claim 1, further comprising a second layer formed on the second surface of the substrate, the second layer comprising a plurality of islands separated by a plurality of trenches and consisting of an optical element layer. **Claim 3** The optical element laminate according to claim 1, wherein each of the plurality of islands has a cross-sectional dimension selected from the group consisting of a polygonal shape, a rounded shape, a tapered shape, or a combination thereof. **Claim 4** The optical element laminate according to claim 2, wherein each of the plurality of islands is aligned in one or more rows, each row being along one or more axes extending across the second layer, and each of the one or more rows of the plurality of islands is spaced apart from each other at equal distances. **Claim 5** The optical element laminate according to claim 1, wherein the plurality of islands comprises an arrangement selected from the group consisting of an aligned arrangement, a random arrangement, a patterned arrangement, or a combination thereof. **Claim 6** The optical element laminate according to claim 2, wherein the second layer is aligned with the first layer. **Claim 7** The optical element laminate according to claim 2, further comprising a third layer formed on the first layer, the third layer comprising a plurality of islands separated by a plurality of trenches and consisting of an optical element layer. **Claim 8** The optical element laminate according to claim 7, further comprising a fourth layer formed on the third layer, the fourth layer comprising a plurality of islands separated by a plurality of trenches and consisting of an optical element layer. **Claim 9** The optical element laminate according to claim 7, further comprising a fifth layer formed on the second layer, the fifth layer comprising a plurality of islands separated by a plurality of trenches and consisting of an optical element layer. **Claim 10** The optical element layer laminate according to claim 9, further comprising a sixth layer formed on the fifth layer, wherein the sixth layer includes a plurality of islands separated by a plurality of trenches and is composed of an optical element layer.

11. An optical element layer laminate, comprising: A substrate having a first surface, the substrate comprising one of the components of a CCD, a CMOS, a VCSEL, an LED, an OLED, and a μLED; A first layer formed on the first surface of the substrate, the first layer comprising a first plurality of islands separated by a first plurality of trenches, and a first filling material provided in the first plurality of trenches and on the first plurality of islands, and being composed of an optical element layer; A second layer formed on the first layer, the second layer comprising a second plurality of islands separated by a second plurality of trenches, and a second filling material provided in the second plurality of trenches and on the second plurality of islands, and being composed of an optical element layer; and A third layer formed on the second layer, the third layer comprising a third plurality of islands separated by a third plurality of trenches and a third filling material provided in the third plurality of trenches and on the third plurality of islands, and being composed of an optical element layer. The optical element layer laminate comprising the above.

12. The optical element layer laminate according to claim 11, wherein each of the first plurality of islands and the second plurality of islands has a cross-sectional dimension selected from the group consisting of a polygonal shape, a rounded shape, a tapered shape, or a combination thereof.

13. The optical element layer laminate according to claim 11, wherein the second layer is aligned with the first layer.

14. The optical element layer laminate according to claim 11, wherein each of the first plurality of islands and the second plurality of islands has an arrangement selected from the group consisting of an aligned arrangement, a random arrangement, a patterned arrangement, or a combination thereof.

15. The optical element layer laminate according to claim 11, wherein the second plurality of islands on the second layer are aligned to form an aligned arrangement.

16. The optical element layer laminate according to claim 11, wherein the third plurality of islands on the third layer are aligned to form an aligned arrangement.

17. An optical element layer laminate, comprising: A substrate having a first surface and a second surface, the substrate comprising one of the components of a CCD, CMOS, VCSEL, LED, OLED, and μLED. A first layer formed on the first surface of the substrate, the first layer comprising a first plurality of islands separated by a first plurality of trenches and consisting of an optical element layer, and A second layer formed on the second surface of the substrate, the second layer comprising a second plurality of islands separated by a second plurality of trenches and consisting of an optical element layer, an optical element layer laminate comprising the second layer.

18. The optical element layer laminate according to claim 17, wherein each of the first plurality of islands and the second plurality of islands has a cross-sectional dimension selected from the group consisting of a polygonal shape, a rounded shape, a tapered shape, or a combination thereof.

19. The optical element layer laminate according to claim 17, wherein the second layer is aligned with the first layer.

20. The optical element layer laminate according to claim 17, wherein each of the first plurality of islands and the second plurality of islands has an arrangement selected from the group consisting of an aligned arrangement, a random arrangement, a patterned arrangement, or a combination thereof.

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