Metasurface coating

Abstract

A method comprising disposing a coating (208) on a first surface (202) of a substrate (204) and on a metasurface (200) on the first surface of the substrate; and imprinting the coating to cause the coating surface to have predetermined features. An apparatus comprising a substrate; a metasurface on a first surface of the substrate; and a coating on the metasurface and the first surface of the substrate, a surface of the coating defining a functional structure.

Description

Background Technology

[0001] A metasurface is a surface with a distributed nanostructure that can be arranged to interact with light in a specific way. In some cases, metasurfaces are coated. Coatings with specific characteristics can provide beneficial effects. Summary of the Invention

[0002] In one aspect, this disclosure describes a method comprising: forming a coating on a first surface of a substrate and on a metasurface of the first surface of the substrate; and imprinting the coating to give the surface of the coating predetermined features.

[0003] The implementation of this method may include one or more of the following: Imprint coating involves pressing the surface of an impression onto the surface of a coating, wherein the surface includes a structure that imparts predetermined features to the coating. The predetermined features include a roughness less than a predetermined maximum roughness.

[0004] In some embodiments, the predetermined features include optical structures defined by the surface of the coating. The optical structures include diffractive optical structures. The optical structures include lenses. The optical structures include anti-reflective structures. The optical structures include features with dimensions between 10 nm and 100 nm. The predetermined features include hydrophobicity or hydrophilicity. The imprinted coating gives the coating a predetermined thickness.

[0005] In some embodiments, the imprint coating includes pressing a facet of an imprint against a surface of a coating, wherein the facet includes spacers, wherein the facet is pressed against the surface of the coating until one end of the spacers contacts a first surface of the substrate, wherein the height of the spacers is equal to a predetermined thickness. The imprint coating also includes pressing a facet of an imprint against a surface of a coating, wherein the spacers are located on a first surface of the substrate, wherein the facet is pressed against the surface of the coating until one end of the spacers contacts the facet of the imprint, wherein the height of the spacers is equal to a predetermined thickness.

[0006] In some embodiments, the coating comprises a polymer. The metasurface includes a nanostructure operable to interact with light waves to alter at least one of the amplitude or phase of the light waves. Imprinting the coating so that the surface of the coating is parallel to a first surface of the substrate. The method includes depositing a second coating on a second surface of the substrate, the second surface of the substrate being located on a side of the substrate opposite to the first surface of the substrate; and imprinting the second coating to give the surface of the second coating a second predetermined feature.

[0007] This disclosure also describes an apparatus comprising: a substrate; a metasurface on a first surface of the substrate; and a coating on the metasurface and the first surface of the substrate, the surface of the coating defining a functional structure.

[0008] In some embodiments, the surface of the coating defines an optical functional structure. The optical functional structure includes a diffractive optical structure. The optical functional structure includes an optical lens. The optical functional structure includes an anti-reflective structure. The functional structure includes a hydrophobic or hydrophilic structure. The functional structure includes features with dimensions between 10 nm and 100 nm. The coating comprises a polymer.

[0009] In some embodiments, the metasurface includes a nanostructure operable to interact with light waves to alter at least one of the amplitude or phase of the light waves. The surface of the coating has a roughness less than a predetermined maximum roughness. The device includes a second coating on a second surface of a substrate, the second surface of the substrate being located on a side of the substrate opposite to a first surface of the substrate, wherein the surface of the second coating defines a second functional structure. The coating has a thickness greater than 10 micrometers.

[0010] This disclosure also describes a system comprising: a coating deposition apparatus; a mold aligner; and a controller communicatively coupled to the mold aligner and the coating deposition apparatus, wherein the system is configured to perform operations including: depositing a coating on a first surface of a substrate and on a metasurface of the first surface of the substrate; and imprinting the coating to give the surface of the coating predetermined features.

[0011] This disclosure also describes modules. For example, a module may include a light-emitting device; and a metasurface device, wherein the metasurface device includes a substrate, a metasurface on a first surface of the substrate, and a coating on the metasurface and the first surface of the substrate, the surface of the coating defining a functional structure, and wherein the metasurface device is configured to interact with light generated by the light-emitting device.

[0012] The present invention also describes a module comprising: a photosensitive device; and a metasurface device, wherein the metasurface device includes a substrate, a metasurface on a first surface of the substrate, and a coating on the metasurface and the first surface of the substrate, the surface of the coating defining a functional structure, and wherein the metasurface device is configured to interact with light incident on the module and transmit the modified light to the photosensitive device.

[0013] Specific embodiments of the subject matter described in this disclosure can be implemented to achieve one or more advantages. For example, in some embodiments, the coating can protect the underlying nanostructure of the metasurface from mechanical damage. In some embodiments, the coating can be composed of cost-effective materials. In some embodiments, imprint coating is a more cost-effective means of surface modification than alternative manufacturing methods. In some embodiments, the coating can protect the metasurface from chemical reactions. In some embodiments, the surface of the coating can introduce optical functionality, non-optical functionality, or both. In some embodiments, a more uniform coating thickness can be maintained throughout the substrate surface. In some embodiments, the coating surface can have lower roughness and / or higher smoothness. In some embodiments, when multiple coatings are provided on the metasurface, the coating surface can have specific characteristics. In some embodiments, coatings can be provided on multiple surfaces of the substrate.

[0014] Details of one or more embodiments are set forth in the accompanying drawings and the following description. Other aspects, features, and advantages will be apparent from the description and drawings, as well as from the claims. Attached Figure Description

[0015] Figures 1A-1D This is a schematic diagram showing an example of an embossing process on a coating.

[0016] Figures 2A-2B This is a schematic diagram showing another example of an embossing process on a coating.

[0017] Figures 3A-3B This is a schematic diagram showing an example of an embossing process on two coatings.

[0018] Figure 4 This is a schematic diagram showing an example of two coatings on a metasurface.

[0019] Figures 5A-5B This is a schematic diagram illustrating an example of an embossing process using spacers.

[0020] Figures 6A-6B This is a schematic diagram showing another example of an embossing process using spacers.

[0021] Figure 7 This is a block diagram of an example of a system used to perform an embossing process.

[0022] Figure 8 This is a schematic diagram of an instance of a display module. Detailed Implementation

[0023] This disclosure relates to coatings formed on metamaterial surfaces. In certain embodiments, this disclosure describes coatings embossed onto metamaterial surfaces to give the coated surface predetermined characteristics.

[0024] Metasurfaces are surfaces with distributed arrays of nanostructures. These nanostructures can interact with light waves individually or collectively. For example, nanostructures can alter the local amplitude, local phase, or both of incident light waves.

[0025] When nanostructures are arranged in specific patterns, metasurfaces can act as optical elements, such as lenses, lens arrays, beam splitters, diffusers, polarizers, or other optical components. In some cases, metasurfaces can perform optical functions traditionally performed by refractive and / or diffractive optical elements. However, metasurfaces can also perform other functions, including polarization control, negative refractive index transmission, beam deflection, eddy current generation, polarization conversion, optical filtering, and plasmonic optics.

[0026] Nanostructures can be mechanically fragile. For example, a nanostructure on a substrate surface may become detached from the substrate due to mechanical stress (e.g., scratching along the surface, or pressure applied to the nanostructure toward the substrate). In some cases, nanostructures may also be chemically unstable, causing them to react with their surroundings in undesirable ways (e.g., oxidation when exposed to water or atmospheric oxygen).

[0027] Furthermore, contaminants on nanostructures can mechanically and / or chemically damage them, or impair their proper optical function. Inoperable nanostructures, besides rendering devices inoperable, can also jeopardize safety. For example, a laser beam could be deflected into a user's eye by water droplets on a metasurface. As another example, a wetted metasurface has a changed refractive index around it; this change alters the metasurface's optical properties and can cause collimated light to penetrate the metasurface and enter the user's eye.

[0028] Therefore, in some cases, it may be beneficial to apply a protective coating to the metasurface and then perform further treatment steps on the coating to impart predetermined characteristics to it.

[0029] like Figure 1A As shown, some embodiments include a metasurface 100 on the surface 102 of the substrate 104. The metasurface 100 includes a plurality of individual nanostructures 106.

[0030] For example, each nanostructure 106 may be a protruding pillar or other structure with a defined shape. In some embodiments, the nanostructure 106 is L-shaped, V-shaped, and / or U-shaped. In some embodiments, the nanostructures 106 are arranged in a two-dimensional (2D) array on the substrate surface 102. In some embodiments, the nanostructures 106 are strips arranged in a one-dimensional (1D) array on the substrate surface 102. In some embodiments, the nanostructures 106 are arranged in other patterns, such as concentric rings. In some cases, each nanostructure 106 may be used as, for example, an antenna.

[0031] Each nanostructure 106 may have a size, for example, tens of nanometers (nm) or hundreds of nanometers (nm). In some embodiments, each nanostructure 106 has a size between 10 nm and 100 nm. In some embodiments, each nanostructure 106 has a size between 100 nm and 500 nm. In some embodiments, each nanostructure 106 has a size less than 1 μm. In some embodiments, each nanostructure 106 has a size less than 10 μm. For other embodiments, the size of the nanostructures may be different.

[0032] For example, the metasurface 100 can be fabricated using additive lithography, subtractive lithography, or both. The metasurface 100 may include one or more of the following: a plasma material (e.g., aluminum-doped zinc oxide), a semiconductor (e.g., silicon), and a dielectric (e.g., silicon oxide).

[0033] The substrate 104 may be, for example, a semiconductor substrate, such as a silicon wafer. In some embodiments, the substrate 104 is a flexible substrate, such as plastic.

[0034] In some embodiments, substrate 104 includes Figure 1A Other features and structures not shown. For example, substrate 104 may include a laser that generates light that interacts with metasurface 100. As another example, substrate 104 may include an on-chip waveguide that directs light to metasurface 100.

[0035] like Figure 1B As shown, a coating 108 is provided on the substrate surface 102 and the metasurface 100.

[0036] In some embodiments, coating 108 is a polymer deposited by spin coating. In some embodiments, coating 108 is deposited using spray deposition, dip coating, printing, or vapor deposition processes (e.g., chemical or physical vapor deposition). Coating 108 may include one or more of the following: polymers, spin-coated glass, nanoparticles dispersed in a solvent, other spin-coated materials, or materials deposited by means other than spin coating.

[0037] Materials other than polymers can also be used for coating 108. If the coating 108 is to be imprinted, the material can be a material that is deposited relatively soft and subsequently hardened (or can be hardened). If the coating 108 is not imprinted, the coating 108 can be any material that has sufficient physical and chemical resistance, optical properties that do not interfere with the proper operation of the metasurface 100, and a surface that can be functionalized, as described below.

[0038] Coating 108 may be composed of materials with specific characteristics. For example, coating 108 may be optically transparent in a wide or narrow band suitable for a specific function (e.g., transparent in an optical band in which the underlying metasurface 100 is optically operable). Coating 108 may be chemically and / or physically resistant and durable to protect the underlying metasurface 100. Coating 108 may be relatively chemically impermeable to prevent environmental chemicals (e.g., oxygen in the atmosphere) from penetrating coating 108 and chemically interacting with metasurface 100. Coating 108 may be electrically insulating. Coating 108 may be thermally insulating or thermally conductive (e.g., if coating 108 is thermally conductive, the coating may enhance device cooling).

[0039] After coating 108 is applied, coating 108 can be characterized by one or more parameters. For example, the surface 110 of the coating can be characterized by a roughness (e.g., root mean square roughness) that describes the typical roughness across the coating surface 110. Surface roughness may be largely unavoidable at this point in the manufacturing process, for example, inherent to the coating deposition method used or the choice of coating material. A coating surface 110 with too high a roughness may cause undesirable optical effects, such as deflection or reflection. For example, coating surface 110 may have a roughness higher than the maximum desired roughness.

[0040] After the coating 108 is applied, the coating 108 can also be characterized by one or more thicknesses 112. The coating 108 may have a substantially uniform thickness 112 throughout the entire coating 108, or the thickness 112 may vary. For example, in an embodiment where the coating 108 is deposited by spin coating, the thickness 112 may vary along the radius of rotation. In some embodiments, the deposited coating 108 may have a uniform thickness 112 that is difficult to control precisely. A coating 108 with an undesirable thickness 112, or with a non-uniform thickness 112, can lead to undesirable optical effects, such as reflection.

[0041] The structure beneath coating 108 can allow coating 108 to have varying thickness 112 and / or high roughness. For example, if vapor deposition is used to deposit coating 108, coating 108 can be conformally coated on a rough or uneven surface beneath coating 108, such that coating 108 itself is rough or has a non-uniform thickness.

[0042] In some embodiments, at least to control the roughness and / or thickness of the coating 108, an impression 114 is used to imprint the coating 108, such as... Figure 1C As shown. The surface 116 of the impression 114 is brought into contact with the coating surface 110, and the impression 114 is pressed against the substrate surface 102. Imprinting can impart predetermined or specified features to the coating surface 110.

[0043] In some embodiments, the mold 114 is pressed against the substrate surface 102 with a predetermined pressure or predetermined spatial amplitude. In some embodiments, the mold 114 is heated before or during imprinting, such that the mold 114 is at an elevated temperature during imprinting. This can cause the coating 108 to soften and become more easily shaped by the mold 114. In some embodiments, the coating 108 is at an elevated temperature during imprinting. In some embodiments, the mold is pressed against the coating 108 for a predetermined period of time. In some embodiments, ultraviolet (UV) imprinting can be used, for example, as an alternative to thermal imprinting. UV imprinting typically involves pressing the mold into the coating 108 while the coating is in a deformable state, and then applying UV radiation to cure the coating.

[0044] like Figure 1D As shown, when the impression 114 is removed after imprinting, the coating 108 has a relatively smooth coating surface 111. The smooth coating surface 111 is provided by the corresponding smooth surface 116 of the impression 114; that is, the structure of surface 116 provides the structure corresponding to the coating 108. After imprinting, the coating surface 111 can be smooth enough that the imprinted coating surface 111 has a roughness, for example, less than a desired specified maximum roughness. In some embodiments, the roughness is small enough not to degrade the desired optical function of the device, for example, due to undesirable light scattering. In some embodiments, the roughness is less than... RMS, less than RMS, less than RMS, less than RMS, less than RMS or less RMS.

[0045] The roughness of the portion of the coated surface 111 excluding the structure intentionally defined by the coated surface can be characterized, as follows regarding Figures 2A-2B As described.

[0046] In some embodiments, imprinting imparts an optically flat surface. For example, when λ is the wavelength of light configured to interact with the metasurface, the coated surface 111 may have a flatness less than λ, less than λ / 2, less than λ / 4, less than λ / 20, or less than λ / 100.

[0047] After imprinting, the coating 108 may also have a defined thickness 113, for example, corresponding to the distance the mold 114 is pressed against the substrate surface 102. In some embodiments, the defined thickness 113 corresponds to the minimum distance between the surface 116 of the mold 114 and the substrate surface 102 during imprinting.

[0048] In some embodiments, the thickness 113 is greater than 1 micrometer. For example, in some embodiments, the coating 108 has a thickness 113 between 1 micrometer and 10 micrometers. In some embodiments, the thickness 113 is greater than 10 micrometers. For example, in some embodiments, the thickness 113 is between 10 micrometers and 50 micrometers. In some embodiments, the thickness 113 is greater than 50 micrometers. In some embodiments, the thickness 113 is optically thick, for example, thicker than several wavelengths of light interacting with the metasurface 100.

[0049] In some embodiments, coating 108 is less than 1 micrometer. In some embodiments, coating 108 is an anti-reflective coating, for example, a quarter-wavelength anti-reflective coating.

[0050] In some embodiments, coating 108 provides optical effects that can alter the optical functionality of metasurface 100. For example, coating 108 may have a refractive index that changes the interaction between light and metasurface 100. Metasurface 100 may be designed to account for the optical effects caused by coating 108.

[0051] In some embodiments, after imprinting, the coating surface 111 is substantially parallel to the substrate surface 102. This can result in less deflection of light incident on the coating surface 111 relative to the metasurface 110 compared to a case where the coating surface 111 is not parallel to the substrate surface 102.

[0052] In some embodiments, the coating 108 is cured or otherwise hardened before, after, or both before and after embossing. Curing may include, for example, thermal curing or optical curing (e.g., ultraviolet (UV) curing).

[0053] In some implementations, depositing and imprinting polymer coatings can be faster and / or more cost-effective compared to alternative materials and / or manufacturing techniques. For example, a polymer coating can be deposited over the entire wafer, and an imprinting die can imprint the coating over the entire wafer in a single imprinting step to produce a uniform coating thickness across the wafer scale. The wafer can then be diced into individual devices. In contrast, some other manufacturing techniques (e.g., photolithography performed on a polymer coating, or photolithography performed on a non-polymer coating) can be slower and / or more expensive. Polymer coatings can be particularly advantageous in conjunction with the imprinting processes described in this disclosure, at least because the polymer coating can be deposited in a state of malleability (e.g., flexibility) that facilitates imprinting.

[0054] In some embodiments, the coating 108 is formed only on a portion of the substrate 104. In some embodiments, a portion of the coating 108 is removed from a portion of the substrate 104.

[0055] Figures 2A-2B A process for setting functionalized coatings on metamaterial surfaces is shown. Figure 2A In this process, the metasurface 200 is located on the substrate surface 202 of the substrate 204. The coating 208 is located on the metasurface 200 and the substrate surface 202, and can be applied using, for example, the method described above for coating 108.

[0056] The mold 214 is used to imprint the coating 208 for manufacturing. Figure 2B The apparatus shown. The surface 216 of the impression has a structure that introduces feature 218, and the imprinting causes the corresponding feature 220 to be applied. Figure 2B The coating surface 222 is shown. Each feature 218 defined by the face 216 of the impression can have dimensions of tens of nm or hundreds of nm (e.g., depth or lateral width). In some embodiments, each feature 218 has a dimension between 10 nm and 100 nm. In some embodiments, each feature 218 has a dimension between 100 nm and 500 nm. In some embodiments, each feature 218 has a dimension less than 1 μm. In some embodiments, each feature 218 has a dimension less than 10 μm. For other embodiments, the aforementioned dimensions may be different.

[0057] Feature 220 defines a patterned structure 224 having one or more functions. In some embodiments, the function is an optical function. For example, the patterned structure 224 may include diffractive optical elements. The patterned structure 224 may include one or more of a beam splitter, diffractive lens, microlens, optical diffuser, or other optical device (or equivalently perform one or more functions). For example, in the case of a diffractive lens, the patterned structure 224 may include concentric rings of feature 220 configured to minimize aberrations and / or directly focus light, having different heights and widths.

[0058] The patterned structure 224 itself can be a metasurface. For example, each feature 220 can be a nanostructure, and features 220 can interact with light waves individually or collectively. In some cases, features 220 can alter the local amplitude, local phase, or both of the incident light wave. Each feature 220 can have a size of tens of nm or hundreds of nm. In some embodiments, each feature 220 has a size between 10 nm and 100 nm. In some embodiments, each feature 220 has a size between 100 nm and 500 nm. In some embodiments, each feature 220 has a size less than 1 μm. In some embodiments, each feature 220 has a size less than 10 μm. For some other embodiments, the aforementioned dimensions may be different.

[0059] Furthermore, in some cases, each feature 220 may have a size smaller than the wavelength of light interacting with the metasurface 200. Additionally, in some cases, each feature 220 may have a size similar to the size of the nanostructure 206 of the metasurface 200.

[0060] The patterned structure 224 may function as a diffraction and antireflection device. For example, the patterned structure 224 may include a diffraction grating. The patterned structure 224 may include a surface texture that produces antireflection properties. For example, each feature 220 may be a pyramid, such that the coating 208, after imprinting, is an antireflection coating based on the pyramid's reflected light.

[0061] In some embodiments, coating 208 is thinner than conventional optical devices configured to provide the optical functions of coating 208. For example, patterned structure 224 may include a lens, and coating 208 may be thinner than a discrete lens having the same optical effect as a lens of patterned structure 224. By reducing the necessary height of the device including coating 208, coating 208 can provide the advantage of space saving.

[0062] In some embodiments, the patterned structure 224 has non-optical functions. For example, the patterned structure 224 may be hydrophobic (e.g., comprising an array of pillars that reduce the contact area of ​​liquids on the coating surface 222). The patterned structure 224 may be hydrophilic. The patterned structure 224 may be self-cleaning (e.g., comprising nanostructures to create a hydrophobic surface).

[0063] In addition to the patterned structure 224, the post-imprint coating 208 may also have a set thickness 213 defined by the imprinting process, as shown in the reference. Figures 1A-1D As described.

[0064] Although Figure 2B The same feature 220 defined by the coating surface 222 is shown, but in some embodiments, there are multiple different features defined by the coating surface, which individually or collectively perform multiple functions.

[0065] As used in this disclosure, "imprinting" should be understood to include other processes that can result in the coating on the metasurface and the substrate surface having predetermined characteristics, such as... Figure 1D and Figure 2B As shown. For example, "imprinting" can include one or more of embossing, debossing, and nanoimprinting. While this disclosure shows an example of the mold moving toward the substrate, in some embodiments, the substrate moves toward the mold.

[0066] Furthermore, despite Figure 1D , Figure 2B While the devices described throughout this disclosure are fabricated using an imprinting process, the devices themselves are the subject of this disclosure. Devices include a substrate, a metasurface on the substrate surface, and coatings on the metasurface and the substrate surface, which may provide advantages and have features described elsewhere in this disclosure, regardless of the method of fabrication of the device. For example, the surface of the coating may define a functional structure, as described elsewhere in this disclosure. The coating may be fabricated using non-imprinting methods while still remaining within the scope of the devices described in this disclosure.

[0067] In some embodiments, the mold 214 is composed of silicon and / or glass. In some embodiments, the mold 214 is a working mold (e.g., a nickel pad) having a structure established by a master mold.

[0068] In some embodiments, the device includes a respective coating on each of opposite sides of the substrate. For example... Figure 3AAs shown in the example, metasurface 300 is located on a first substrate surface 302 of substrate 304. A first coating 308 is located on metasurface 300 and the first substrate surface 302, and a second coating 326 is located on a second opposing substrate surface 328. Coatings 308 and 326 can be deposited using, for example, the methods described above for coating 108. In some embodiments, coatings 308 and 326 are deposited simultaneously using, for example, a dip-coating method.

[0069] As described above, molds 314 and 315, having corresponding imprint surfaces 316 and 334, are used for imprinting coatings 308 and 326. In some embodiments, the same mold is used for imprinting molds 314 and 315, and the imprinting of the corresponding substrate surfaces 302 and 328 is performed sequentially. In some embodiments, molds 314 and 315 are different molds. In some embodiments, the imprinting of the corresponding substrate surfaces 302 and 328 is performed simultaneously.

[0070] Figure 3B An apparatus is shown comprising coatings 308 and 326 on two substrate surfaces 302 and 328, wherein coatings 308 and 326 have corresponding coating surfaces 322 and 330, each coating surface having a corresponding predetermined feature. Coating surfaces 322 and 330 define corresponding patterned structures 324 and 332. Patterned structures 324 and 332 respectively include features 325 and 333. In some embodiments, impression surfaces 316 and 334 are substantially identical to each other, such that features 325 and 333 and patterned structures 324 and 332 are substantially identical to each other and have substantially the same function. In some embodiments, such as Figures 3A-3B As shown, the impression surfaces 316 and 334 are different, and the resulting patterned structures 324 and 332 include different features.

[0071] Each patterned structure 324, 332 can have a function, as shown in the reference above. Figure 2B The corresponding functions may be the same as or different from each other.

[0072] In some embodiments, coatings 308 and 326 have defined thicknesses 313 and 317, respectively, which may be the same as or different from each other.

[0073] Coatings applied to the surfaces of two substrates to create surfaces with predetermined characteristics can improve the function of the device. The potential benefits of the coating on the metasurface 300 have been described above. A second coating 326 on the second substrate surface 328 can also provide benefits. For example, the coated surface may include anti-reflective properties. The coated surface may include hydrophobic properties, and / or the second coating 326 may be chemically and / or physically resistant to protect the substrate 304, and consequently, to protect the metasurface 300. As described above, the coated surface 333 may have other optical functions.

[0074] Although Figures 3A-3B A metasurface is shown only on the first substrate surface 302. In some embodiments, the metasurface may be located on both substrate surfaces 302 and 328.

[0075] In some implementations, such as Figure 4 As shown, the device includes multiple coatings on a substrate surface. A metasurface 400 is located on a substrate surface 402 of a substrate 404. A first coating 408 is located on the metasurface 400 and the substrate surface 402, and a second different coating 436 is located on the first coating 408.

[0076] In some embodiments, each coating 408, 436 is applied and processed as described above. For example, a first coating 408 may be spin-coated and then embossed, followed by a second coating 436 spin-coated and then embossed. One or both of coatings 408, 436 may include a surface having predetermined characteristics.

[0077] However, in some embodiments, coatings 408 and 436 are configured and / or processed in different ways. For example, in some embodiments, the first coating 408 is a thin antireflective coating. For example, the first coating 408 may comprise silicon oxide or silicon nitride, and is, for example, a quarter-wavelength antireflective coating. In some embodiments, the first coating 408 comprises multiple layers.

[0078] In some embodiments, coatings 408 and 436 are composed of different materials. In some embodiments, coatings 408 and 436 have similar refractive indices. In some embodiments, coatings 408 and 436 have different refractive indices and may, for example, form a multilayer antireflective coating together. In some embodiments, coatings 408 and 436 together form a bandpass filter, a high or low filter, a notch filter, or a line filter.

[0079] In some embodiments, the first coating 408 is deposited using vapor deposition techniques such as chemical vapor deposition or atomic layer deposition. Because vapor deposition can result in a conformal film with a substantially constant thickness relative to the underlying structure, the surface 410 of the first coating 408 will be relatively rough, for example, having a roughness higher than the desired maximum roughness, or exhibiting thickness variation. As mentioned above, this can impair the operability and / or safety of the device. Even when the first coating 408 is not deposited using a vapor deposition technique, the first coating 408 can still have relatively high roughness or thickness variation.

[0080] A second coating 436 (e.g., a polymer) can be applied and, for example, formed by embossing the second coating 436 to include a surface having predetermined features. As described above, the predetermined features can be one or more of the following: a roughness less than the desired maximum roughness, a structure with optical functions, a structure with non-optical functions, and a structure with specific feature dimensions. Therefore, in some cases, the second coating 436 can improve the optical function of the device regardless of the possible thickness variations and roughness of the first coating 408.

[0081] In some embodiments, multiple coatings may be located on one or more surfaces of a substrate, the substrate having at least one coating on multiple surfaces, and / or more than two coatings may be located on the substrate surface. For example, one or more additional coatings on... Figure 3B The middle layer can be located on coatings 308 and 326.

[0082] In some implementations, spacers are provided to define the coating thickness. For example... Figures 5A-5B As shown, the metasurface 500 is located on the substrate surface 502 of the substrate 504. The coating 508 is located on the metasurface 500 and the substrate surface 502. The mold 540 includes spacers 542 having a height 544.

[0083] In some embodiments, the spacer 542 is made of the same material as the rest of the impression 540. In some embodiments, the spacer 542 is made of a different material. The spacer 542 may be designed not to deform or break under the pressure that the spacer may experience during imprinting.

[0084] When the mold 540 is used to imprint the coating 508, the distal end 546 of the spacer 542 contacts the substrate surface 502. Therefore, after imprinting, the thickness 513 of the coating 508 is substantially equal to the height 544 of the spacer 542. Using one or more spacers can help increase the uniformity of the coating thickness across the entire substrate 504.

[0085] In some embodiments, portions 548 of the contact spacers 542 on the substrate surface 502 leave very little or no coating 508 after imprinting. This feature can optically isolate portions of the metasurface 500 from portions 548 on different sides.

[0086] In some embodiments, the impression 540 includes, for example, a plurality of spacers 542 located at intervals on the impression 540. The presence of the plurality of spacers 542 can, for example, allow a coating on a large substrate to be imprinted with a common coating thickness achieved across the entire substrate. In some embodiments, such as Figures 5A-5B As shown, the mold 540 is aligned with the substrate 504 such that a portion 548 of the contact spacer 542 on the substrate surface 502 does not have the metasurface 500.

[0087] In some embodiments, portion 548 defines a line between separating devices; for example, nanostructure 550 may be part of a first device, and nanostructure 552 may be part of a second device. In some embodiments, portion 548 may be aligned with a cutting track.

[0088] In some embodiments, the impression 540 includes a groove near the spacer 542. During imprinting, the groove can provide space to guide excess coating material into it. Because the groove can be located between devices (e.g., in section 548), the accumulation of coating material at the groove does not impair device function.

[0089] In some implementations, such as Figures 6A-6B As shown, spacers 654 are disposed on substrate 604. Metasurface 600 is located on substrate surface 602, and coating 608 is located on both metasurface 600 and substrate surface 602. Spacers 654 may be formed as part of a manufacturing process that also forms metasurface 600. In some embodiments, spacers 654 are formed during processing separate from metasurface 600.

[0090] The mold 656 is used to imprint the coating 608 such that the distal end 658 of the spacer 654 contacts the surface 660 of the mold 656. After imprinting, the thickness 613 of the coating 608 is substantially equal to the height of the spacer 654. Using one or more spacers can help increase the uniformity of the coating thickness across the entire substrate 604.

[0091] In some embodiments, substrate 604 includes, for example, a plurality of spacers 654 located on substrate 604 at intervals. In some embodiments, spacers 654 define lines between separating devices; for example, nanostructure 662 may be part of a first device, and nanostructure 664 may be part of a second device. In some embodiments, spacers 654 may be aligned with dicing tracks.

[0092] In some embodiments, the impression 656 includes a groove configured to be positioned near the spacer 654. During imprinting, the groove can provide space to guide excess coating material into it. Because the groove can be located between devices, the accumulation of coating material at the groove does not impair device function.

[0093] Figures 5A-6BThe methods and apparatus shown include spacers that can be combined with previously shown methods and apparatus. For example, imprinting with spacers may result in a specific roughness on the coated surface. Imprinting with spacers can be performed on one or both of two coatings on two respective opposing surfaces of a substrate having a metasurface on at least one of its surfaces. One or both of the two opposing surfaces of the substrate may include one or more respective spacers. Imprinting with spacers can be performed on one or more coatings in a multi-coating stack.

[0094] The methods and apparatus described in this disclosure can be implemented in a system. Figure 7 An example of system 701 is shown, which includes a metasurface 700 on substrate surface 702 of substrate 704. A coating deposition apparatus 766 is operable to deposit a coating on the substrate. An impression aligner 768 is operable to align an impression with substrate 704 and perform imprinting on the coating. The coating deposition apparatus 766 and the impression aligner 768 are configured to perform at least the methods described above. A controller 770 is operable to communicate with one or both of the coating deposition apparatus 766 and the impression aligner 768 and transmit commands 772 to perform the deposition and / or imprinting process.

[0095] In some embodiments, alignment is performed with reference to the metasurface 700. In some embodiments, spacers on the reference substrate ( Figure 7 Alignment is performed (not shown in the image). In some embodiments, alignment is performed with reference to other features on the substrate, which may be formed, for example, by photolithography. In some embodiments, alignment and / or imprinting are automated (e.g., performed by a mold aligner 768). The controller 770 can be programmed with process parameters, such as the rotational frequency used for rotation on the coating, or the pressure applied during the imprinting process. In some embodiments, one or more steps are performed manually.

[0096] In some embodiments, a silicon wafer having a metasurface on a first wafer surface is moved along an assembly line. The wafer is immersed in a tank containing a liquid polymer, resulting in the formation of a coating on each of the first wafer surface and a second opposing wafer surface. The wafer is held in place while a die aligner scans the first wafer surface for alignment features, aligns a heated first die based on the alignment features, and lowers the first die toward the first wafer surface at a predetermined pressure. Spacers on the first die set the final height of the coating on the first wafer surface, and features on the face of the first die cause the coated surface on the first wafer surface to include textured pyramids that reduce the reflection of incident light.

[0097] In the example process, the wafer is then rotated (e.g., by a robotic arm), and a second imprinting process is performed on a coating on the surface of the second wafer by a mold aligner or a different mold aligner. The parameters of the second mold and the second imprinting process may be the same as or different from the parameters of the first mold and the first printing process.

[0098] In the example process, after two imprinting processes are completed, the wafer passes through a UV chamber to cure two coatings. The underlying metasurface is now protected by the coatings, which also provide additional functionality. The wafer can then be diced into individual devices.

[0099] In some embodiments, as described above, the means of introducing one or more metasurfaces and one or more coatings on the metasurfaces can be integrated into the module. For example... Figure 8 As shown, module 874 includes a substrate 876 and a light-emitting component 878 coupled to or integrated into the substrate 876. The light-emitting component 878 may include, for example, a laser (e.g., a vertical-cavity surface-emitting laser) or a light-emitting diode.

[0100] Light 880 generated by the light-emitting element 878 is transmitted through the housing and then to the coated metasurface device 884. As described above, the coated metasurface device 884 is operable to modify the light 880, such that the modified light 886 is transmitted outside the module 874. For example, the module 874, using the coated metasurface device 884, can generate one or more of structured light, diffused light, and patterned light. The housing may include, for example, spacers 882 separating the light-emitting element 878 and / or the substrate 876 from the coated metasurface device.

[0101] When integrated into module 874, the coated metasurface device 884 can offer advantages over devices without a coated metasurface. For example, the coating on the metasurface can enhance eye safety by reducing the impact of contaminants on the surface of device 884. The coating can make module 874 more efficient by having anti-reflective properties, making the generated light 880 less likely to be reflected and more likely to be transmitted as modified light 886. The coating can make module 874 more stable by protecting device 884 in adverse environments. The coating can have optical functions for modifying light 880 to produce modified light 886. Compared to discrete optical components that replace the coating, the coating can allow device 884 to be thinner, saving space in module 874 and / or reducing the overall required size of module 874.

[0102] In some implementations... Figure 8Module 874 is a photosensitive module (e.g., an ambient light sensor), component 878 is a photosensitive component (e.g., a photodiode, pixel, or image sensor), light 886 is light incident on module 874, and light 880 is light altered by the coated metasurface device 884. For example, the coated metasurface device 884 can focus patterned light onto the photosensitive component 878. As described above, compared to conventional optical devices, the coating on the coated metasurface device 884 can reduce the size of module 874, protect device 884 in adverse environments, and increase the detection efficiency of module 874 by reducing the amount of reflected light.

[0103] In some embodiments, module 874 may include a light-emitting component and a photosensitive component. For example, module 874 may emit light that interacts with its environment and is then received back by module 874, allowing module 874 to act as, for example, a proximity sensor or a 3D mapping device. When integrated into such a module, coated metasurface devices can provide the advantages described above.

[0104] These modules can be, for example, part of a time-of-flight camera or an active stereo camera. These modules can be integrated into systems such as mobile phones, laptops, wearable devices, and automobiles.

[0105] According to embodiments of the present disclosure, an improved method and apparatus for depositing and imprinting a coating on a metasurface to give the coating surface predetermined characteristics are described.

[0106] The various aspects and functional operations of the subject matter described in this specification can be implemented in digital electronic circuits or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or one or more combinations thereof. Therefore, the aspects of the subject matter described in this specification can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium for execution or control by a data processing device. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of substances affecting machine-readable propagation signals, or one or more combinations thereof. In addition to hardware, the device may also include code that creates an execution environment for the computer program in question, for example, code constituting processor firmware.

[0107] A computer program (also known as a program, software, software application, script, or code) can be written in any programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored as part of a file that contains other programs or data (e.g., one or more scripts stored in a markup language document), as a single file dedicated to the program in question, or as multiple coordinated files (e.g., files storing one or more modules, subroutines, or portions of code). Computer programs can be deployed to execute on a single computer or on multiple computers located at a site or distributed among multiple sites and interconnected via a communication network.

[0108] The processes and logic flows described in this specification can be executed by one or more programmable processors that execute one or more computer programs to perform functions by manipulating input data and generating outputs. The processes and logic flows can also be executed by dedicated logic circuitry, and the device can be implemented as dedicated logic circuitry, such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit).

[0109] Processors suitable for executing computer programs include, for example, general-purpose and special-purpose microprocessors, and any one or more processors of any type of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are a processor for executing instructions and one or more storage devices for storing instructions and data. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor storage devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROMs and DVD-ROMs. The processor and memory may be supplemented by or incorporated into special-purpose logic circuitry.

[0110] While specific implementations have been described in detail, various modifications can be made. As an example, the processes depicted in the figures do not necessarily require the specific order or sequence shown to achieve the desired results. In some implementations, multitasking and parallel processing may be advantageous. Therefore, other implementations are within the scope of the claims.

Claims

1. A method comprising: A coating is disposed on a first surface of a substrate and on a metasurface on the first surface of the substrate and in contact with the metasurface, wherein the metasurface comprises a nanostructure operable to interact with a light wave to change at least one of the amplitude or phase of the light wave. and The coating is imprinted to give the surface of the coating predetermined features, wherein the predetermined features include an optical structure defined by the surface of the coating.

2. The method according to claim 1, wherein imprinting the coating comprises: The surface of the impression is pressed against the surface of the coating, wherein the surface includes a structure that imparts predetermined features to the surface of the coating.

3. The method according to claim 1, wherein the predetermined feature includes a roughness less than a predetermined maximum roughness.

4. The method according to claim 1, wherein the optical structure comprises a diffractive optical structure.

5. The method according to claim 1, wherein the optical structure comprises a lens.

6. The method according to claim 1, wherein the optical structure includes an anti-reflective structure.

7. The method of claim 1, wherein the optical structure includes features with dimensions between 10 nm and 100 nm.

8. The method according to claim 1, wherein the predetermined feature includes hydrophobicity or hydrophilicity.

9. The method of claim 1, wherein the coating is embossed to give the coating a predetermined thickness.

10. The method of claim 9, wherein imprinting the coating comprises: The surface of the impression is pressed against the surface of the coating, wherein the surface includes spacers, and the surface is pressed against the surface of the coating until one end of the spacers contacts a first surface of the substrate, and The height of the spacer is equal to the predetermined thickness.

11. The method of claim 9, wherein imprinting the coating comprises: The surface of the impression is pressed against the surface of the coating, wherein the spacer is located on a first surface of the substrate, and the surface is pressed against the surface of the coating until one end of the spacer contacts the surface of the impression. The height of the spacer is equal to the predetermined thickness.

12. The method of claim 1, wherein the coating comprises a polymer.

13. The method of claim 1, wherein the coating is imprinted such that the surface of the coating is parallel to a first surface of the substrate.

14. The method of claim 1, further comprising: A second coating is formed on a second surface of a substrate, the second surface of the substrate being located on the side of the substrate opposite to the first surface of the substrate; and The second coating is imprinted to give the surface of the second coating a second predetermined feature.

15. An apparatus comprising: Substrate; A metasurface on a first surface of a substrate, wherein the metasurface comprises a nanostructure operable to interact with a light wave to alter at least one of the amplitude or phase of the light wave. and A coating on and in contact with the metasurface and on a first surface of the substrate, the surface of which defines an optical functional structure.

16. The apparatus of claim 15, wherein the optical functional structure comprises a diffractive optical structure.

17. The apparatus of claim 15, wherein the optical functional structure comprises an optical lens.

18. The apparatus of claim 15, wherein the optical functional structure includes an anti-reflective structure.

19. The apparatus of claim 15, wherein the surface of the coating comprises a hydrophobic structure or a hydrophilic structure.

20. The device of claim 15, wherein the optical functional structure includes features with dimensions between 10 nm and 100 nm.

21. The apparatus of claim 15, wherein the coating comprises a polymer.

22. The apparatus of claim 15, wherein the surface of the coating has a roughness less than a predetermined maximum roughness.

23. The apparatus of claim 15, comprising: A second coating on a second surface of a substrate, the second surface of which is located on the side of the substrate opposite to the first surface of the substrate. The surface of the second coating defines a second functional structure.

24. The apparatus of claim 15, wherein the coating has a thickness greater than 10 micrometers.

25. A system for fabricating structures having distributed nanostructures, the system comprising: Coating deposition apparatus; Imprint aligner; and A controller communicatively connected to the mold alignment device and the coating deposition apparatus, wherein the system is configured to perform operations including: A coating is disposed on a first surface of a substrate and on and in contact with a metasurface on the first surface of the substrate, wherein the metasurface comprises a nanostructure operable to interact with a light wave to change at least one of the amplitude or phase of the light wave. and An embossed coating is used to give the surface of the coating a predetermined feature, wherein the predetermined feature includes an optical structure defined by the surface of the coating.

26. A module comprising: Light-emitting device; and Metasurface device, wherein the metasurface device comprises: Substrate, A metasurface on a first surface of a substrate, wherein the metasurface comprises a nanostructure operable to interact with a light wave to alter at least one of the amplitude or phase of the light wave, and A coating on and in contact with the metasurface and on a first surface of the substrate, the surface of which defines an optical functional structure, and The metasurface device is configured to interact with light generated by the light-emitting device.

27. A module comprising: Photosensitive device; and Metasurface device, wherein the metasurface device comprises: Substrate, A metasurface on a first surface of a substrate, wherein the metasurface comprises a nanostructure operable to interact with a light wave to alter at least one of the amplitude or phase of the light wave, and A coating on and in contact with the metasurface and on a first surface of the substrate, the surface of which defines an optical functional structure, and The metasurface device is configured to interact with light incident on the module and transmit the altered light to the photosensitive device.

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