Structured film, and method for forming a pattern on a substrate using the same.

Abstract

A structured film for forming a pattern on a substrate includes a polymeric support layer, an adhesive layer, an etch resist layer disposed between the polymeric support layer and the adhesive layer, a structured resin layer disposed between the polymeric support layer and the etch resist layer, and one or more unstructured layers disposed between the etch resist layer and the adhesive layer. The structured resin layer has a structured major surface including a plurality of textured structures. The etch resist layer at least partially fills spaces between adjacent textured structures to substantially planarize the structured major surface. A method for forming a pattern on a substrate using the structured film is described.

Description

[Background technology]

[0001] Structured articles, such as nanostructured articles, are useful in a variety of applications, including optical applications such as optical metasurface applications. [Overview of the project]

[0002] This specification generally relates to structured films that can be used to form patterns on a substrate, methods for forming patterns on a substrate using structured films, and articles comprising structured films disposed on a substrate.

[0003] In some aspects of this specification, a structured film for forming a pattern on a substrate is provided. The structured film includes a polymeric support layer, an adhesive layer, an etching resist layer disposed between the polymeric support layer and the adhesive layer, a structured resin layer disposed between the polymeric support layer and the etching resist layer, and one or more unstructured layers disposed between the etching resist layer and the adhesive layer, with a total thickness of less than 10 micrometers. The structured resin layer has a structured main surface comprising a plurality of engineered structures. The etching resist layer substantially flattens the structured main surface by at least partially filling the spaces between adjacent engineered structures.

[0004] In some aspects of this specification, a method for forming a pattern on a substrate is provided. This method can utilize a structured film comprising a polymeric support layer, one or more unstructured layers, an etching resist layer disposed between the polymeric support layer and one or more unstructured layers, and a structured resin layer disposed between the polymeric support layer and the etching resist layer. The structured resin layer has a structured main surface comprising a plurality of processed structures. The etching resist layer substantially flattens the structured main surface and defines an etching resist pattern by at least partially filling the spaces between adjacent processed structures. This method comprises, in order, providing a structured film, bonding the structured film to a substrate such that the polymeric support layer is oriented away from the substrate, removing at least the polymeric support layer leaving at least the etching resist layer and one or more unstructured layers disposed on the substrate, and etching into one or more unstructured layers so as to transfer an etching resist pattern to one or more unstructured layers and thereby form a pattern on the substrate.

[0005] In some aspects of this specification, optical articles are provided. The optical article comprises a substrate, an optically transparent etching stop layer disposed on the substrate, and a structured film disposed on the etching stop layer. The structured film comprises one or more patterned layers and an adhesive layer that bonds one or more patterned layers to the etching stop layer. The structured film comprises a plurality of structures that define a plurality of voids separating adjacent structures. At least some of the voids penetrate the structured film and extend to the etching stop layer.

[0006] Some aspects of this specification provide an optical article comprising a waveguide and a structured film disposed on the waveguide. The structured film includes an optical bonding layer that bonds the structured film to the waveguide, one or more patterned layers disposed on the optical bonding layer, and an etching stop layer disposed between the one or more patterned layers and the optical bonding layer. The one or more patterned layers are formed by forming patterns on one or more unstructured layers, and the light transmittance of the one or more unstructured layers for substantially perpendicular incident light is at least 50% for a first wavelength W1 in the range of at least 400 nm to 2500 nm. The light transmittance of the etching stop layer for substantially perpendicular incident light is at least 50% for at least the first wavelength W1. The refractive index of the optical bonding layer has an imaginary part of less than 0.01 for at least the first wavelength W1, and the average thickness of the optical bonding layer is greater than 5 nm and less than 1 / 4 W1.

[0007] These and other aspects will become apparent from the detailed description below. However, in no case should this brief summary be construed as limiting the subject matter of the claims. [Brief explanation of the drawing]

[0008] [Figure 1A] This is a schematic cross-sectional view of a structured film according to several embodiments. [Figure 1B] This is a schematic cross-sectional view of a structured film according to several embodiments. [Figure 1C] This is a schematic diagram of the method for producing the structured film shown in Figure 1A. [Figure 2A] A schematic diagram of a method for forming a pattern on a substrate is shown. [Figure 2B] A schematic diagram of a method for forming a pattern on a substrate is shown. [Figure 3A] This is a schematic cross-sectional view of an article that can be formed using a structured film according to several embodiments. [Figure 3B]Schematic cross-sectional view of an article that can be formed using a structured film, according to some embodiments. [Figure 3C] Schematic cross-sectional view of an article that can be formed using a structured film, according to some embodiments. [Figure 4A] Schematic cross-sectional view of an exemplary structured film, according to some embodiments. [Figure 4B] Schematic cross-sectional view of an exemplary structured film, according to some embodiments. [Figure 5A] Schematic cross-sectional view of an article including an etching resist layer having a structure with two different heights, according to some embodiments. [Figure 5B] Schematic view of a method of forming a pattern on a substrate by etching through the etching resist layer of the article of FIG. 5A. [Figure 5C] Schematic view of a method of forming a pattern including a processed structure having a plurality of heights on a substrate. [Figure 6] Schematic cross-sectional view of an article including a structured film disposed on a substrate, according to some embodiments. [Figure 7] Schematic cross-sectional view showing light incident on one or more unstructured layers, according to some embodiments.

MODE FOR CARRYING OUT THE INVENTION

[0009] In the following description, reference is made to the accompanying drawings, which form a part of this specification and in which various embodiments are shown by way of example. The drawings are not necessarily to scale. It should be understood that other embodiments may be conceived and implemented without departing from the scope or spirit of this specification. Therefore, the following mode for carrying out the invention is not to be construed in a limiting sense. ​​Nanoimprint lithography (NIL) is a three-step process for nanopatterning the surface of an etched wafer. First, a nanoimprint resist is spin-coated onto the surface of the etched substrate. Next, a nanopatterned template wafer is used to form the coated resist layer. Finally, the etched wafer, along with the structured resist layer, is subjected to a reactive ion etching (RIE) process, which is used to transfer the structure from the resist layer to the etched wafer or a pattern transfer layer on the surface of the etched wafer. NIL is described, for example, in Smith et al.'s "Employing Step and Flash imprint lithography for gate-level patterning of a MOSFET device," Proc. SPIE 5037, Emerging Lithographic Technologies VII, (June 16, 2003), doi:10.1117 / 12.490142, and, for example, in Microlithography (authors: D. Resnick and H. Schift, 3rd edition, editors: B. Smith and K. Suzuki, CRC Press, Francis and Taylor, May 21, 2020), ISBN 9781439876756, pp. 594-675, Chapter 11, "Imprint Lithography." Other nanostructured articles are described, for example, in International Patent Application Publication No. 2020 / 095258 (Van Lengerich et al.) and No. 2020 / 097319 (Wolk et al.).

[0011] According to some embodiments of this specification, a structured film is provided that enables the user of the film to form a patterned layer on a substrate without the need to spin-coat and mold a resist layer. This structured film can be used in a continuous roll-to-roll or roll-to-plate process to form a structure on a substrate substantially more efficiently than conventional NIL batch processes. Using this structured film, a structure can be formed on a substrate substantially larger than the semiconductor wafer format used in conventional NIL batch processes, or on a display glass substrate typically used in large-format NIL or roll-to-plate NIL. In some embodiments, the structured film is used to form a structure on a region of a substrate, the maximum dimensions of which this region are, for example, greater than 100 mm, 200 mm, 300 mm, 450 mm, or 600 nm. In some embodiments, the maximum dimensions of the structured film are, for example, greater than 4 m, or greater than 5 m, or greater than 10 m, or greater than 50 m, or greater than 100 m. In some embodiments, a roll of the structured film is provided. In some embodiments, the roll is converted into a sheet form.

[0012] A structured film may include a patterned etching resist layer and one or more unstructured layers. The structured film can be bonded to a substrate, and then a pattern can be formed on the substrate by transferring the pattern from the etching resist layer by etching one or more previously unstructured layers.

[0013] Figure 1A is a schematic cross-sectional view of a structured film 100 according to several embodiments. Figure 1B is a schematic cross-sectional view of a structured film 103 according to several embodiments. Figure 1C is a schematic diagram of a method for producing a structured film 100. The structured film 100 includes a layer 140 for bonding the structured film to a substrate. Layer 140 may be an adhesive layer, such as an optically transparent adhesive layer. The structured film 100 includes an etching resist layer 125 and one or more unstructured layers 135, the unstructured layers may be patterned by etching through the etching resist layer 125 after the structured film 100 has been bonded to the substrate (see, for example, Figure 2A). In some embodiments, the structured film 100 includes a polymeric support layer 130, an adhesive layer 140, an etching resist layer 125 disposed between the polymeric support layer 130 and the adhesive layer 140, a structured resin layer 127 disposed between the polymeric support layer 130 and the etching resist layer 125, and one or more unstructured layers disposed between the etching resist layer 125 and the adhesive layer 140, with a total thickness of less than 10 micrometers. The one or more unstructured layers may refer to layer(s) 135, which is schematically shown as a single layer in Figure 1A, but may include multiple layers (e.g., layers 135a, 135b shown in Figure 4B), or to layer 135', which includes layers 135, 131, and 137. In some embodiments, layer 131 is a mask layer (e.g., a layer adapted to be patterned, which can then be used as an etching mask for patterning one or more layers 135). The mask layer may also be referred to as a hard mask layer. In some embodiments, layer 137 is an etching stop layer (for example, a layer adapted to provide a common etching depth in the etching process).

[0014] The total thickness of layer(s) 135 is s1, and the total thickness of layer(s) 135' is s1'. In some embodiments, the total thickness of one or more unstructured layers (e.g., s1 and / or s1') is less than 10 micrometers, or less than 5 micrometers, or less than 2 micrometers, or less than 1 micrometer, or less than 0.5 micrometers. In some such embodiments, or other embodiments, the total thickness is at least 10 nm. In some such embodiments, or other embodiments, layer(s) 135 and / or layer(s)' are thin enough that layer(s) 135 and / or 135' are not self-supporting. A self-supporting layer(s) is a layer that can maintain its shape (e.g., maintain its length and width without the layer(s) folding or crumpling) and maintain its integrity (e.g., without tears or cracks) during normal handling without any additional support layers. The layers 135(one or more) and / or 135' may be thin enough that they cannot maintain their shape and / or integrity without additional layers(one or more), such as polymeric support layers 130.

[0015] The structured resin layer 127 has a structured main surface 128 containing a plurality of processed structures 129. The etching resist layer 125 substantially flattens the structured main surface 128 by at least partially filling the spaces between adjacent processed structures 129 (i.e., defining a substantially flat main surface such as the main surface 121 of the etching resist layer 125). The etching resist layer 125 may have an etching resist pattern 111 (see, for example, Figure 2A) defined by the structured main surface 128. The etching resist layer 125 has a main surface 228 facing the structured main surface 128 of the structured resin layer 127. The main surface 228 is typically substantially conforming to the structured main surface 128 (e.g., the deviation from the conforming state is 20% or less or 10% or less of t2).

[0016] In some embodiments, the fabricated structure 129 has length and width in orthogonal directions (e.g., x and y directions), where each direction is orthogonal to the thickness direction (z direction). In some embodiments, the multiple fabricated structures 129 are or include multiple nanostructures. A nanostructure is a structure having at least two orthogonal dimensions (e.g., at least two of height, length, and width) in the range of about 1 nm to about 1000 nm. A fabricated structure (e.g., a fabricated nanostructure) is a structure intentionally fabricated in a predetermined geometric shape (e.g., a predetermined length, width, and height). Some typical shapes of fabricated structures include, but are not limited to, rectangular, triangular, and trapezoidal prisms, fins, cylindrical and truncated conical prisms, and other such shapes. In some embodiments, the average aspect ratio of the fabricated structure (height divided by length or width or the largest lateral dimension (orthogonal to height)) is, for example, at least 0.5, or at least 1, or at least 2, or at least 5, or at least 10. In some embodiments, the fabricated structure has non-perpendicular sidewall angles of at least 1 degree, or at least 2 degrees, or at least 3 degrees. In other embodiments, the fabricated structure may have perpendicular sidewalls. Depending on the functionality and manufacturability of the application, the fabricated structure may be arranged in regular or irregular pitch, orientation, and / or shape (e.g., the structure appears to be randomly arranged, but is a pseudo-random distribution formed from an underlying deterministic process).

[0017] In some embodiments, the etching resist layer 125 includes a residual layer 142 between the substantially unstructured main surface 121 of the etching resist layer 125 and a plurality of processed structures 129. The residual layer may be described as the portion of the etching resist layer that lies above the upper surface (in the positive z direction) of the processed structures 129. In some embodiments, the ratio of the average (unweighted average) thickness t1 of the residual layer 142 to the average height t2 of the plurality of processed structures is less than 1, or less than 0.5, or less than 0.3, or less than 0.25. In some embodiments, t1 / t2 is, for example, in the range of 0.001 to 0.5. The main surface 121 can be considered substantially unstructured if the height of any structures that may exist on its surface is substantially less than the average height t2 (e.g., less than 20%, or less than 10%, or less than 5%, or less than 3% of the average height t2). The main surface 121 can be considered substantially flat if any deviation from planarity that is substantially greater than the average height t2 on a length scale in the transverse direction (e.g., in the xy plane) (e.g., 100 times t2 or 1000 times t2) is substantially smaller than the average height t2 (e.g., less than 20%, 10%, 5%, or 3% of the average height t2). In some embodiments, the amount of planarization (P%) of a substantially planarized surface is greater than 50%, more preferably greater than 75%, and most preferably greater than 90%, and the amount of planarization is given by P = (1 - (a1 / a2)) * 100%, where a1 is the relief height of the surface layer (e.g., the substantially planarized layer) and a2 is the feature height of the features covered by the surface layer, which is disclosed in detail in P. Chiniwalla, IEEE Trans.Adv.Packaging 24(1), 2001, 41. In some embodiments, the plane Ra of the main surface 121 is less than 30 nm, or less than 20 nm, or less than 10 nm, or less than 5 nm, or less than 2 nm, or less than 1 nm, or less than 0.5 nm.

[0018] Layer 140 can have an average thickness in a range suitable for a given application. In some embodiments, the average thickness ta of layer 140 is less than 250 nm, or less than 200 nm, or less than 150 nm, or less than 100 nm, or less than 75 nm, or less than 50 nm, or less than 40 nm, or less than 30 nm. In some such embodiments, or in other embodiments, the average thickness ta is at least 5 nm, or at least 10 nm, or at least 15 nm. In some embodiments, for optical applications, for example, the average thickness ta is selected to be less than 1 / 4 of the target wavelength. For example, for visible light, an average thickness of less than 100 nm or substantially less than 100 nm (e.g., less than 50 nm) may be preferred, but for near-infrared light, the average thickness may be, for example, up to 250 nm, and may be even greater if longer wavelengths are targeted. Having a thickness of less than 1 / 4 of the target wavelength allows the resulting structure formed within one or more unstructured layers to be coupled to evanescent waves, for example, within the substrate. This allows the resulting structure to be used, for example, for photoextraction. In applications where coupling with evanescent waves is not the target, there are no particular restrictions on the average thickness ta, and it may be in the range of, for example, 10 nm to 5 micrometers.

[0019] Layer 140 may be a polymer or monomer bonding layer and / or an optically transparent adhesive layer. Suitable optically transparent adhesives include, for example, those available from Norland Products Inc. (Cranbury, NJ). Other suitable adhesives include thermosetting materials such as those available from Dow Chemical Company (Midland, MI) under the trade name CYCLOTENE. Still other suitable adhesives include thermally activated adhesives such as those available from KRATON Polymers (Huston, TX) under the trade name KRATON. Suitable adhesive layers, including thin adhesive layers (e.g., less than 50 nm thick), are described, for example, in U.S. Patents 7,521,727 (Khanarian et al.), 7,053,419 (Camras et al.), 6,709,883 (Yang et al.), and 6,682,950 (Yang et al.).

[0020] Figure 1B is a schematic cross-sectional view of structured film 103, which may correspond to structured film 100, except that an optional additional layer 133 is positioned between the structured resin layer 127 and the polymeric support layer 130, and another optional additional layer 132 is positioned between the polymeric support layer 130 and the structured resin layer. The additional layer 133 may be a dynamic separation layer, which may be adapted to facilitate the separation of the polymeric support layer 130 and the structured resin layer 127 upon activation (e.g., by irradiation), as further described elsewhere in this specification. Other structured films described herein (e.g., structured films schematically shown in Figures 4A-4B) may optionally include the additional layer 133 and / or the additional layer 132. In some embodiments, the additional layer 133 is included and the additional layer 132 is omitted. In some embodiments, the additional layer 132 is included and the additional layer 133 is omitted.

[0021] Figure 1C is a schematic diagram of a method for producing a structured film 100. The method in Figure 1C may be carried out, for example, in a continuous roll-to-roll process. In step A0, a structured resin layer 127 is formed on a polymeric support layer 130. The polymeric support layer 130 may be, for example, a polyethylene terephthalate (PET) film or a polycarbonate film that can be dimensionally stabilized (e.g., heat-set). Other suitable materials for the polymeric support layer 130 include, for example, other polyesters or copolyesters, polyurethanes, polymethyl methacrylates, polystyrenes, polyimides, polyethylene naphthalates, polypropylenes, and cyclic olefin copolymers.

[0022] The structured resin layer 127 may also be formed using different pattern printing, transfer, tiling, copying, or replication techniques, such as photolithography, electron beam lithography, grayscale lithography, two-photon lithography, nanoimprint lithography, or a master mold produced by microcontact printing (μCP). Suitable materials for the structured resin layer 127 include polymerizable compositions containing acrylate or methacrylate components, and thermoplastic materials such as polymethyl methacrylate, polycarbonate, polypropylene, polyethylene, polystyrene, polyester, or polyamide. The thermoplastic material may be molded onto the structured surface of the tool using heat and pressure, as generally described in U.S. Patent No. 3,515,778 (Fields et al.) and No. 4,097,634 (Bergh), and cured by cooling. The structured resin layer 127 may be made from a thermoplastic material that flows at a lower temperature than the polymeric support layer 130, for example. In some such embodiments, or in other embodiments, the structured resin layer 127 and the polymeric support layer 130 are separated by an interface. Alternatively, in some embodiments, the structured resin layer 127 and the polymeric support layer 130 may be made from the same thermoplastic material, for example, so that the structured resin layer 127 and the polymeric support layer 130 form a monolithic body. Replication techniques (e.g., nanoreplication) may include, for example, casting and curing the resin onto the structured surface of the tool. The structured resin layer 127 may be, for example, a crosslinked acrylate layer or a methacrylate layer. For example, in some embodiments, the resin is an acrylic resin, and curing the resin includes crosslinking the resin. Suitable casting and curing methods, as well as resins suitable for use in such methods, are described, for example, in U.S. Patent No. 5,175,030 (Lu et al.) and No. 5,183,597 (Lu), and U.S. Patent Application Publication No. 2012 / 0064296 (Walker, Jr. et al.).Other useful methods and / or materials for forming the structured resin layer 127 are described, for example, in U.S. Patent No. 8,658,248 (Anderson et al.), No. 5,811,183 (Shaw et al.), and No. 6,045,864 (Lyons et al.). Structured tools may be manufactured using any preferred manufacturing method, such as photolithography or electron beam lithography, to prepare a tooling master, a metal copy thereof, a polymer copy of either the tooling master or its metal copy, a polymer copy of such a polymer copy, a directly written tool or a copy thereof, a copy of a structured liner or a copy thereof. Preferred manufacturing methods are described, for example, in International Patent Application Publication No. 2009 / 002637 (Zhang et al.), and in U.S. Patent Applications Publication Nos. 2007 / 0065636 (Merrill et al.) and 2014 / 0193612 (Yu et al.), and in U.S. Patent No. 8,460,568 (David et al.). The tools may be made, for example, by diamond turning. Exemplary systems and methods of diamond turning are described, for example, in U.S. Patent Nos. 7,350,442 (Ehnes et al.), 7,328,638 (Gardiner et al.), and 6,322,236 (Campbell et al.). An example of patterning subwavelength diffraction gratings is described in "Diamond turning of high-precision roll-to-roll imprinting molds for fabricating subwavelength gratings" by Chun-Wei Liu, Jiwang Yan, and Shih-Chieh Lin (Opt.Eng.55(6), 064105(2016, DOI:10.1117 / 1.OE.55.6.064105).

[0023] In step B0, an etching resist layer 125 is placed on the structured resin layer (e.g., by coating). In step C0, a layer 135' is deposited on the etching resist layer 125. In step D0, an adhesive layer 140 is placed on the layer 135' (e.g., by coating). The mask layer 131, the etching stop layer 137, and the layer(s) 135 can be deposited using various deposition methods, taking into account the material type and layer thickness. Suitable deposition methods include, for example, chemical vapor deposition (CVD), sputter coating, physical vapor deposition (PVD), atomic layer deposition (ALD), or a combination thereof. Thin layers or films can be coated on flat or structured surfaces using coating methods known in the art, such as slot die coating, slide coating, curtain coating, knife coating, blade coating, dip coating, and spin coating. For example, slot die coating equipment is described in U.S. Patent No. 5,639,305 (Brown et al.) and No. 7,591,903 (Maier et al.). For example, spin coaters are described in U.S. Patent No. 6,033,728 (Kikuchi et al.).

[0024] In some embodiments, the structured film 100 or 100' (see, for example, Figure 2B) or other structured films described herein comprises a polymeric support layer 130, one or more unstructured layers 135 or 135', an etching resist layer 125 disposed between the polymeric support layer 130 and one or more unstructured layers, and a structured resin layer 127 disposed between the polymeric support layer 130 and the etching resist layer 125, wherein the structured resin layer 127 has a structured main surface 128 comprising a plurality of processed structures, and the etching resist layer 125 substantially flattens the structured main surface 128 and defines an etching resist pattern 111 by at least partially filling the spaces between adjacent processed structures (see, for example, Figure 2A). The structured film 100 or 100' or other structured films described herein can be used to form a pattern 110 on a substrate 120, as schematically shown in Figures 2A and 2B. In some embodiments, the method includes, in order: providing a structured film 100 or 100'; bonding the structured film to a substrate 120 such that the polymeric support layer 130 faces away from the substrate (for example, by bonding the structured film to the substrate using an adhesive layer 140) (step A in Figure 2A or step A' in Figure 2B); removing at least the polymeric support layer 130, leaving at least an etching resist layer 125 and one or more unstructured layers 135 or 135' disposed on the substrate 120 (step B or C); and etching into one or more unstructured layers so as to transfer an etching resist pattern 111 to one or more unstructured layers and thereby form a pattern 110 on the substrate 120 (step E). In some embodiments, for example, as schematically shown in Figures 1A-1B and Figure 2A, the structured film includes an adhesive layer 140 disposed on one or more unstructured layers. In some embodiments, as schematically shown in Figure 2B, for example, bonding the structured film 100' to the substrate 120 includes placing an adhesive layer 140 on the substrate 120, and then placing the structured film 100' on the adhesive layer 140.

[0025] In some embodiments, the etching resist pattern 111 and the pattern 110 on the substrate 120 have substantially the same geometric shape (for example, the length, width, and thickness of the structure of the etching resist pattern 111 may each be within 20% or 10% of the respective length, width, and thickness of the structure of the pattern 110). In other embodiments, the etching resist pattern 111 and the pattern 110 on the substrate 120 have substantially the same pattern in plan view (for example, the length and width of the structure of the etching resist pattern 111 may each be within 20% or 10% of the respective length and width of the structure of the pattern 110), but may have different thicknesses or heights that can be adjusted by etching conditions.

[0026] In some embodiments, the structured resin layer 127 is peelably attached to the polymeric support layer 130 or the etching resist layer 125. In some embodiments, the structured resin layer 127 is permanently attached to the etching resist layer 125 and peelably attached to the polymeric support layer 130. This is schematically shown in step B of Figure 2A. In this case, the method for forming the pattern 110 on the substrate 120 using the structured film 100 or 100' or other structured film may include the step (step D) of etching the structured resin layer 127 (e.g., reactive ion etching) to expose the etching resist pattern 111 of the etching resist layer 125. In some embodiments, the structured resin layer 127 is peelably attached to the etching resist layer 125 and permanently attached to the polymeric support layer 130. This is schematically shown in step C of Figure 2A. As a result of step C or step D in Figure 2A, an article 105 is obtained, which includes an etching resist layer 125 and one or more unstructured layers 135 disposed between the etching resist layer 125 and the substrate 120, with the one or more unstructured layers 135 bonded to the substrate 120 by an adhesive layer 140.

[0027] Two layers are detachably attached to each other if they can be separated from each other with little or no damage to either layer (for example, with such minimal damage that a person with normal vision (20 / 20 vision) cannot easily see the damage with the naked eye). The detachability of the first and second layers includes the placement of a third layer (and optionally, an additional layer) between the first and second layers, wherein the third layer is adapted to facilitate the separation of the first and second layers (for example, the third layer may be adapted to split or separate from at least one of the first and second layers). The third layer may be adapted to facilitate the separation of the first and second layers only after activation of the third layer (for example, by irradiation, chemical activation, or thermal activation). For example, the third layer may be a dynamic separation layer. The dynamic separation layer is a layer that can be changed from a first state to at least a second state (for example, by activating the separation layer by irradiation), such that in the first state the adhesion is high to at least one adjacent layer, and in the second state the adhesion is low to this at least one adjacent layer. For example, the dynamic separation layer may be a photo-induced stress-mode delamination layer (e.g., a crosslinkable polymer layer, or a polymer layer that can be further crosslinked upon irradiation so that increased crosslinking generates stress that facilitates delamination from adjacent layers (one or more)) and / or a photothermal conversion (LTHC) layer. The dynamic separation layer may include a plurality of sublayers. Suitable dynamic separation layers include carbon black nanocomposites, light-absorbing optical cavities such as thin light-absorbing metal (e.g., aluminum, titanium, or chromium) layers separated by polymer layers such as acrylate layers, and defined by thin (e.g., 10-30 nm) metal (e.g., aluminum, titanium, or chromium) layers. The dynamic separation layer can be formed, for example, from 3M Light-To-Heat Conversion Release Coating (LTHC) Ink (available from 3M Company, St. Paul, MN).Other suitable dynamic separation layers include, for example, the LTHC layers described in U.S. Patent No. 7,977,864 (Bellmann et al.) and U.S. Patent No. 7,670,450 (Lamansky et al.). The dynamic separation layer may contain a soluble near-infrared (NIR) dye, such as one available from HWSands Corp. (Jupiter, FL).

[0028] The layer 133 schematically shown in Figure 1B may be a dynamic separation layer. In some embodiments, an optional additional polymer layer 132 is placed between layer 133 and the structured resin layer 127. Layer 133 may be a dynamic separation layer adapted to be peelably attached to the additional substrate layer 132 during activation. In this case, the dynamic separation layer 133 may be described as being adapted to facilitate separation of the polymeric support layer 130 and the structured resin layer 127 during activation by facilitating separation at the separation interface between the dynamic separation layer 133 and the additional polymer layer 132.

[0029] The structured film can be configured such that the structured resin layer 127 is peelably attached to the polymeric support layer 130 by including a split layer between the structured resin layer 127 and the polymeric support layer 130, or by including a dynamic separation layer 133 (e.g., an LTHC layer) between the structured resin layer 127 and the polymeric support layer 130 and activating the dynamic separation layer (e.g., irradiating the LTHC layer). The radiation can include one or more wavelengths, including visible radiation, infrared radiation, or ultraviolet radiation, from a laser, lamp, or other radiation source. Useful radiation conditions are described, for example, in U.S. Patent No. 7,977,864 (Bellmann et al.). The split layer may be, for example, a low surface energy layer, or a static separation layer, which may be a layer co-extruded with the polymeric support layer 130 and weakly bonded to the polymeric support layer 130, as generally described, for example, in U.S. Patent No. 9,415,561 (Lindquist et al.). For example, in some embodiments, layer 133 in Figure 1B is omitted, and layer 132 is a split layer co-extruded with the polymeric support layer 130. The structured resin layer 127 may be permanently attached to the polymeric support layer 130 without a split layer or dynamic separation layer. The structured film can be configured such that the structured resin layer 127 is peelably attached to the etching resist layer 125 by a peeling treatment of the structured main surface 128 with a low surface energy material, by plasma-induced fluorination of the structured resin layer 127, or by the formulation of an etching resist layer 125 that promotes poor adhesion to the structured resin layer 127 (e.g., by the addition of a silicone component). The structured resin layer 127 may be permanently attached to the etching resist layer 125 without such treatment or additives.

[0030] In some embodiments, the structured film 100, 100' or other structured films described herein include a mask layer 131 disposed between an etching resist layer 125 and one or more unstructured layers 135. In some such embodiments or other embodiments, the structured film 100, 100' or other structured films include an etching stop layer 137 disposed on one or more unstructured layers 135 (for example, on the opposite side of the mask layer 131 and / or between one or more unstructured layers 135 and an adhesive layer 140).

[0031] Figures 3A to 3C are schematic cross-sectional views of articles 350 to 352, respectively, which can be formed by etching article 105 schematically shown in Figure 2A, or, in the case of article 352, by etching an article equivalent to article 105 except that it lacks a mask layer 131. In some embodiments, etching into one or more unstructured layers 135 includes etching a portion of the mask layer 131 through the etching resist layer 125 in a first etching step to form a patterned mask layer 131', and etching into one or more unstructured layers 135 through the patterned mask layer 131' in a second etching step to form a pattern 110 on the substrate 120. For example, step E of the method in Figure 2A may include forming a patterned mask layer 131' in Figure 3A by etching through the etching resist layer 125 in a first etching step (to obtain article 350), and then etching through the patterned mask layer 131' into one or more unstructured layers 135 in a second etching step (thereby patterning layer 135 and obtaining patterned layer 235 and article 351). In some embodiments, etching into one or more unstructured layers 135 includes etching through one or more unstructured layers 135 to an etching stop layer 137 (see, for example, Figures 3B-3C). In some embodiments, the mask layer 131 is omitted, and etching into one or more unstructured layers 135 includes etching through the etching resist layer 125 into one or more unstructured layers 135 (see, for example, Figure 3C). For example, the mask layer 131 may be omitted if a structure with a relatively low aspect ratio is desired, in which case the etching resist layer 125 can act as an etching mask for etching into one or more unstructured layers 135. Alternatively, article 352 may be formed from article 351 by a subsequent etching step that removes the patterned mask layer 131'.Articles 350, 351, and 352, schematically shown in Figures 3A to 3C, respectively, include structured films 400, 402, and 402, respectively, placed on a substrate 120. Structured film 400 includes a patterned layer 131' and unpatterned layers 137 and 140. Structured film 401 includes patterned layers 131' and 235, and unpatterned layers 137 and 140. Structured film 402 includes a patterned layer 235 and unpatterned layers 137 and 140.

[0032] In some embodiments, the first etching step includes reactive ion etching with a first etching gas (etching gas G1 in Figure 2A) having a first composition, and the second etching step includes reactive ion etching with a second etching gas (etching gas G2 in Figure 2A) having a different second composition. In some embodiments, each of the first and second etching gases includes at least one of oxygen, nitrogen trifluoride (NF3), CF4, C2F6, C3F8, SF6, Cl2, and CH4. In some embodiments, the first etching gas includes at least one of oxygen, nitrogen trifluoride (NF3), CF4, C2F6, C3F8, SF6, Cl2, and CH4, and the second etching gas includes at least one of oxygen, nitrogen trifluoride (NF3), CF4, C2F6, C3F8, SF6, Cl2, and CH4 that is not included in the first etching gas. For example, the first etching gas may contain oxygen and Cl2, and the second etching gas may contain oxygen and CF4.

[0033] Etching (e.g., the first and / or second etching step) may be plasma etching. When high aspect ratio structures are desired, ion-assisted plasma treatment is conveniently used. Methods for achieving anisotropic etching include reactive ion etching (RIE), high-density ion source treatment, or a combination of high-density ion source treatment and RIE. High-density plasma can be generated by radiofrequency induction or microwave coupling, or by a helicon ion source. A linear high-density plasma source is particularly advantageous for generating high aspect ratio features. By combining high-density plasma with RIE, it becomes possible to decouple ion generation (by the high-density plasma) from ion energy (by the RIE bias voltage).

[0034] The RIE method involves etching the unprotected portion of a primary surface to form a structure (e.g., a nanostructure) on a substrate. In some embodiments, this method can be performed using a continuous roll-to-roll process referred to as "cylindrical reactive ion etching" (cylindrical RIE). Cylindrical RIE utilizes a rotating cylindrical electrode to provide anisotropically etched nanostructures on the surface of a substrate or article. Generally, cylindrical RIE can be described as follows: A rotatable cylindrical electrode ("drum electrode") powered by high-frequency coupling and a grounded counter electrode are provided inside a vacuum vessel. The counter electrode may include the vacuum vessel itself. An etchant gas is supplied into the vacuum vessel, and a plasma is ignited and maintained between the drum electrode and the grounded counter electrode.

[0035] A continuous substrate with a patterned masking layer can be wrapped around a drum, and the substrate can be etched in a direction perpendicular to the plane of the substrate. By controlling the exposure time of the substrate, a predetermined etch depth can be obtained for the resulting nanostructure. This process can be carried out at an operating pressure of approximately 1 to 10 mTorr. For cylindrical RIEs, see, for example, U.S. Patent No. 8,460,568 (David et al.).

[0036] When multiple materials are present, the chemical interactions of the plasma environment can be controlled to achieve etching selectivity. For example, oxygen and mixtures of oxygen and fluorinated gases are used to etch carbon-containing materials such as polymers, diamond-like carbon, and diamond. The concentration of fluorine in the plasma can be selected to optimize the etching rate and selectivity. Typically, a small amount of fluorinated gas is used to dramatically increase the etching rate of hydrocarbon polymers by up to 300%.

[0037] Silicate materials (silicon dioxide, SiO₂) x To etch materials such as diamond-like glass, silicon nitride, silicon carbide, silicon oxycarbide, polysiloxane, and silsesquioxane (SSQ) resins, a mixture of fluorocarbons, such as CF4, C2F6, and C3F8, is used in combination with oxygen. By obtaining the etching profiles of these materials as a function of the F / O atomic ratio in the plasma feed gas mixture, the etching selectivity between siliceous materials and hydrocarbon polymers can be carefully adjusted. Under oxygen-rich conditions, excellent selectivity is obtained to etch hydrocarbon polymers and diamond-like carbon (DLC) while using siliceous materials as masking layers. Conversely, under fluorine-rich conditions, excellent selectivity is obtained to etch siliceous materials while using hydrocarbon polymer-based masking materials.

[0038] The chemical action of fluorinated plasma can be used to etch other masking materials whose fluorides are volatile, such as tungsten. Chlorine-containing gas mixtures can be used to etch materials whose chlorides are volatile, such as aluminum and titanium. Oxides, nitrides, and carbides of these etchable metals can also be etched by using chlorine-based chemical action. Silicon nitride, aluminum nitride, and titanium oxide are high refractive index materials that can be etched by the chemical action of chlorine.

[0039] The mask layer 131 can be made of any material having suitable etching selectivity for the layer(s) 135. In some embodiments, the mask layer 131 is or includes a metal or a silicon-containing metal oxide. Examples include chromium (Cr), aluminum (Al), copper (Cu), titanium (Ti), tungsten (W), germanium (Ge), iridium (Ir), platinum (Pt), ruthenium (Ru), osmium (Os), rhenium (Re), their alloys, or their silicon-containing oxides. Metal nitrides or metal oxynitrides can also be used. In some embodiments, the mask layer 131 includes SiO2, Si x O y N z (x = 1, y = 1 - 2, z = 0 - 1), or Si x Al y O z (x = 1, y = 0 - 1, z = 1 - 2). Since silicon is a metalloid, silicon oxide, silicon nitride, and silicon oxynitride are considered to be a metal oxide, a metal nitride, and a metal oxynitride, respectively. Useful oxides are described, for example, in U.S. Patent Application No. 2015 / 0214405 (Nachtigal et al.). Useful materials include, for example, titanium nitride (TiN), aluminum oxide (Al2O3), a metal alloy of aluminum and chromium (Al / Cr), Si x C y H z (x = 1, y = 1 - 4, z = 1 - 4), or Si x C y N z H n (x = 1, y = 1 - 4, z = 0 - 1, n = 1 - 4), Si x N y (x = 1, y = 0 - 1), SiO x (x = 1 - 2), SiH x (x = 1 - 4). In some embodiments, indium tin oxide (ITO) is used as the mask layer. Other suitable materials include, for example, diamond-like glass as described in U.S. Patent No. 8,034,452 (Padiyath et al.).

[0040] The etching stop layer 137 can be made from any material having suitable etching selectivity for layer(s) 135. In some embodiments, the etching stop layer 137 may be a metal (e.g., Cr, Al, Ti, Zr, Ta, Hf, Nb, Ce, or an alloy thereof), a metal oxide (e.g., Al2O3 or Si x Al y O z (For example, x=1, y=0~1, z=1~2, etc., an oxide of any of these metals), or Si x O y N z (For example, x=1, y=1~2, z=0~1), or metallic nitrides (for example, nitrides of any of these metals, or Si x O y N z ) or including them. In some embodiments, the etching stop layer 137 is, for example, indium tin oxide, tin oxide, or alumina (Al2O3), or includes them. As a useful material, Si x C y H z (For example, x=1, y=1~4, z=1~4), Si x C y N z H n (For example, x=1, y=1~4, z=0~1, n=1~4), Si x N y (For example, x=1, y=0~1), SiO x (For example, x=1~2), Si x O y N z (For example, x=1, y=1~2, z=0~1), or SiH x (For example, x = 1 to 4) are examples. Other suitable materials include, for example, diamond-like glass. In some embodiments, the etching stop layer 137 is optically transparent, which can be understood as meaning that the average light transmittance of the etching stop layer for substantially perpendicular incident light is at least 60% in the wavelength range of 400 nm to 700 nm.

[0041] The average thickness of the mask layer 131 and / or etching stop layer 137 may be, for example, in the range of about 1 nm to about 200 nm, or about 2 nm to about 50 nm, or about 2.5 nm to about 10 nm. The average thickness of the mask layer 131 may be, for example, less than 50 nm, or less than 25 nm, and / or greater than 5 nm. The average thickness of the etching stop layer 137 may be, for example, less than 25 nm, and / or greater than 2 nm.

[0042] In some embodiments, one or more unstructured layers 135 include an inorganic material such as a metal oxide, nitride, or oxynitride. In some embodiments, one or more unstructured layers 135 include a metal oxide. The metal oxide may be, for example, an oxide of Ti, Zr, Hf, Si, Nb, or Ta. In some embodiments, one or more unstructured layers 135 include a titania (TiO2) layer. While titania is preferred for optical applications involving visible light, other metal oxides may be used for applications involving near-infrared light. In some embodiments, one or more unstructured layers 135 include a polymer layer such as an acrylate (e.g., a crosslinked acrylate) layer.

[0043] In some embodiments, the etching resist layer 125 comprises a silicone-containing polymer. In some embodiments, the etching resist layer 125 comprises a siloxane, silicone, or silsesquioxane. In some embodiments, the etching resist layer 125 comprises a crosslinked acrylate. A suitable etching resist layer is described, for example, in U.S. Patent No. 5,811,183 (Shaw et al.). The total thickness of the etching resist layer 125 may be, for example, in the range of 50 nm to 500 nm (total feature depth t2 + thickness of residual layer t1).

[0044] In some embodiments, one or more unstructured layers 135' include first and second conductive layers (e.g., layers 131 and 137) and a dielectric layer 135 disposed between them, where the first conductive layer (e.g., layer 131) faces an etching resist layer 125. In some embodiments, etching into one or more unstructured layers includes etching through the first conductive layer (e.g., obtaining article 350 schematically shown in Figure 3A). In some embodiments, etching into one or more unstructured layers includes etching through the dielectric layer (e.g., obtaining article 351 schematically shown in Figure 3B). In some embodiments, the pattern on the substrate is configured to provide passive cooling. For example, the pattern can define a metasurface thermal emitter, as commonly described in "Dual-band infrared metasurface thermal emitter for CO2 sensing" (Miyazaki et al.), Applied Physics Letters 105, 121107 (2014), and "Kirchhoff's Thermal Radiation from Lithography-Free Black Metals" (Kumagai et al.), Micromachines 2020, 11,824 (2020). In some embodiments, the structured articles 350, 351 include a first article having a first main surface 122 (for example, a substrate 120 may be the first article) and structured films 400, 401 disposed on the first main surface 122 and configured to provide passive cooling. The first article may generate heat (for example, the first article may be an electronic device that generates heat when operating). The structured films 400, 401 include a bonding layer 140 (for example, an adhesive layer such as an organic and / or polymer adhesive layer) that bonds the structured films 400, 401 to a first main surface 122, a patterned conductive layer 131', an unpatterned conductive layer 131 disposed between the bonding layer 140 and the patterned conductive layer 137', and dielectric layers 135, 235 disposed between the patterned conductive layer 131' and the unpatterned conductive layer 137.The dielectric layer does not have to be patterned (e.g., dielectric layer 135), or it may be patterned (e.g., dielectric layer 235).

[0045] In some embodiments, one or both of the mask layer 131 and the etching stop layer 137 are omitted. Figures 4A and 4B are schematic cross-sectional views of structured films 101 and 102 according to some embodiments, respectively. Structured film 101 may correspond to structured film 100, except that the mask layer 131 is omitted. Structured film 102 may correspond to structured film 100, except that the mask layer 131 is omitted and one or more unstructured layers 135 include at least two unstructured layers 135a and 135b. Structured film 102 may optionally include a mask layer 131 having at least two unstructured layers 135a and 135b. Etching into one or more unstructured layers 135a, 135b may include etching through one or more structured layers to the etching stop layer 137. The etching stop layer 137 may be optionally omitted from either the structured film 101 or 102.

[0046] In some embodiments, one or more unstructured layers include at least one of an inorganic layer and a polymer layer. For example, layer 135 may be an inorganic layer such as a metal oxide layer, or layer 135 may be a polymer layer such as an acrylate layer. As another example, one of the unstructured layers 135a and 135b shown in Figure 4B may be a polymer layer, and the other of the unstructured layers 135a and 135b may be an inorganic layer. A polymer layer can be understood as an organic polymer layer unless otherwise indicated. In some embodiments, one or more unstructured layers include at least one layer which is one or more of an inorganic layer, a metal oxide layer, a polymer layer, a fluoropolymer layer, a dielectric layer, a conductive layer, or a metal layer. In some embodiments, one or more unstructured layers include at least one conductive layer and at least one dielectric layer. For example, one or more unstructured layers 135' may be dielectric layers, which may be metal oxide or polymer layers, and one or both of the layers 131 and 137 of the one or more unstructured layers 135' may be conductive layers, such as metal layers. In some embodiments, one or more unstructured layers 135' include first and second conductive layers (e.g., layers 131 and 137) and an electrically insulating layer (e.g., layer 135) disposed between them. Suitable materials for the conductive layers include metals such as gold, silver, copper, aluminum, and alloys thereof.

[0047] In some embodiments, the multiple processed structures 129 have at least two different heights h1 and h2. Figure 5A is a schematic cross-sectional view of article 205 which may be roughly equivalent to article 105 shown in Figure 2. The etching resist layer 225 includes processed structures 229 having two different heights h1 and h2. The etching resist layer 225 includes a residual layer having a thickness t1. Structures having at least two different heights are useful in thin-film transistor applications, for example, as generally described in U.S. Patent No. 6,861,365 (Taussig et al.) and U.S. Patent No. 7,521,313 (Mea).

[0048] Figure 5B is a schematic diagram of a method for forming a pattern 210 on a substrate 120 by etching through the etching resist layer 225 into one or more unstructured layers 135a, 135b. In step A1, “breakthrough” etching is used to etch through the remaining layers of the etching resist layer 225. In step B1, layer 135a is etched. In step C1, layer 135b is etched. Steps A1, B1, and C1 may be performed using different etching conditions for each different step. For example, reactive ion etching can be used in each step, where different etching gases with different compositions are used in different steps.

[0049] In some embodiments, one or more unstructured layers include a plurality of unstructured layers (e.g., layers 135a and 135b, or layer 135, and at least one of layers 131 and 137). In some embodiments, etching into one or more unstructured layers includes etching into at least one of the plurality of unstructured layers, but does not include etching into at least one other of the plurality of unstructured layers. For example, layer 131 can be etched to form layer 131' as shown in Figure 3A without etching into layer 135. In some embodiments, etching into one or more unstructured layers includes etching into each of the plurality of unstructured layers. For example, one or more unstructured layers may be layers 135 and 131, and the method of forming the pattern may include etching into each of these layers, for example, as schematically shown in Figure 3B. As another example, one or more unstructured layers may be layers 135a and 135b, and the method may include etching into each of these layers, for example, as schematically shown in Figure 5B. In some embodiments, etching into a layer(s) includes etching through a layer(s), such as etching through the layer(s) to an etching stop layer to form a pattern(s), for example (e.g., pattern 110).

[0050] In some embodiments, the monolithic layer is structured to include features having multiple (at least two) heights. Having different feature heights is useful, for example, in waveguide extraction, to improve the uniformity of optical extraction. Figure 5C is a schematic diagram of a method for forming a pattern 310 on a substrate 120 by etching through an etching resist layer 325 into an unstructured layer 135. An adhesive layer 140 is applied to the substrate 120, and then in step A'', a structured film 104 is bonded to the substrate 120. The structured film 104 includes an etching resist layer 325 and a structured resin layer 327. The interface between the etching resist layer 325 and the structured resin layer 327 includes a processed structure having at least two different heights. In step B'', the polymeric support layer 130 and the structured resin layer 327 are removed. In step C'', the layer 135 is etched through the etching resist layer 325 to form a processed structure 335.

[0051] In some embodiments, the etching stop layer 137 is omitted from the structured film (100 or 100', or other structured films described herein). In some such embodiments, the substrate includes the etching stop layer. Figure 6 is a schematic cross-sectional view of an article 300 including a structured film 200 placed on a substrate 120. The substrate 120' includes the etching stop layer 137 placed on the substrate 120. Alternatively, the substrate 120 may be made of a material that functions as an etching stopper so that the layer 137 can be omitted. The structured film 200 includes a patterned layer 235 and an adhesive layer which is also patterned and bonds the structured film 200 to the substrate 120'. The article 300 can be manufactured using the process schematically shown in Figures 2A-2B, except that the films 100, 100' do not include the etching stop layer 137, and instead, the etching stop layer is placed on or defined by the substrate 120 before the structured film 100 is applied.

[0052] Any of the articles described herein (e.g., 150, 300, 350, 351, or 352) may be optical articles, such as articles adapted for use in optical applications (e.g., for transporting or extracting light), or intermediate articles, such as articles adapted for use in optical applications by further processing (e.g., etching). The substrate 120 may be a waveguide or contain a waveguide, or the waveguide may be the substrate 120 or contain a waveguide. The waveguide may be, for example, a glass waveguide or a polymer (e.g., polymethyl methacrylate) waveguide. The waveguide may be, for example, an image-preserving waveguide (e.g., a waveguide in which light containing an image (e.g., light from a display) propagates along the waveguide and then, when extracted from the waveguide, the extracted light retains the image). In some embodiments, the waveguide combiner includes a waveguide and a structure formed on the substrate that defines input and / or output couplers of an optical metasurface. Waveguide combiners are described, for example, in Kress's "Optical waveguide combiners for AR headsets: features and limitations," Proc.SPIE 11062, Digital Optical Technologies 2019, 110620J (July 16, 2019); DOI:10.1117 / 12.2527680.

[0053] The fabricated structure can be used, for example, as a surface relief grating (SRG). As used herein, the term SRG includes cases where the grating is embedded in a material having a different refractive index. In some embodiments, the structured surface of the SRG is exposed (e.g., to air). This structure can be used, for example, for optical incoupling and / or outcoupling (e.g., in augmented reality waveguide elements). Alternatively, or in addition, this structure can be used for exit pupil expansion in augmented reality waveguide elements, for example, as a light distribution element, orthogonal pupil expander, or redirection element. An exemplary example of the use of SRG in an image-preserving waveguide is described, for example, in International Patent Application Publication No. 2019 / 195186 (Peroz et al.).

[0054] In some embodiments, layer 140 may be an optical bonding layer (e.g., an optically transparent adhesive layer) having an imaginary part (κ) of the refractive index for at least a first wavelength W1 of less than 0.1, less than 0.05, less than 0.03, less than 0.01, or less than 0.005, and an average thickness ta greater than 5 nm and less than 1 / 4 W1. The first wavelength W1 may be any wavelength to be considered, such as a visible wavelength (400 nm to 700 nm) or a near-infrared wavelength (700 nm to 2500 nm). The average thickness ta may be less than 0.2 times, less than 0.15 times, or less than 0.1 times the first wavelength W1, or the average thickness ta may be within any range described elsewhere in this specification.

[0055] In some embodiments, the substrate 120 is a waveguide, and an optical article is provided that includes a structured film disposed on the waveguide. In some embodiments, the optical article 150 (see, for example, Figure 2A) includes a waveguide 120 and a structured film 100 disposed on the waveguide 120, with an adhesive layer 140 bonding the structured film 100 to the waveguide 120.

[0056] In some embodiments, the optical article 300 (see, for example, Figure 6) includes a substrate 120, an optically transparent etching stop layer 137 disposed on the substrate 120, and a structured film 200 disposed on the etching stop layer 137. The structured film 200 includes one or more patterned layers 235 and an adhesive layer 240 that bonds one or more patterned layers 235 to the etching stop layer. The structured film 200 includes a plurality of structures 229 that define a plurality of voids 233 separating adjacent structures, and at least some of the voids 233 (e.g., more than 50%, or more than 70%, or more than 80%, or more than 90%, or all or substantially all) penetrate the structured film 200 and extend to the etching stop layer 137. One or more patterned layers 235 can be formed by patterning one or more unstructured layers, which may have optical properties (e.g., transmittance) as further described elsewhere in this specification. In some embodiments, one or more patterned layers 235 include patterned inorganic layers. In some embodiments, each of the one or more patterned layers 235 is a patterned inorganic layer.

[0057] In some embodiments, the optical articles (e.g., articles 350, 351, 352 schematically shown in Figures 3A to 3C) include a waveguide 120 and structured films 400, 401, 402 disposed on the waveguide. In some embodiments, the structured films 400, 401, 402 include an optical bonding layer 140 that bonds the structured films 400, 401, 402 to the waveguide 120 and one or more patterned layers 131' and / or 235 disposed on the optical bonding layer 140. One or more patterned layers 131' and / or 235 are formed by patterning one or more unstructured layers 131' and / or 135 (or, for example, layers 135a and 135b schematically shown in Figures 5A and 5B), wherein the light transmittance of one or more unstructured layers to substantially perpendicular incident light is at least 50% for a first wavelength W1 in the range of at least 400 nm to 2500 nm. The structured film may include an etching stop layer 137 positioned between one or more patterned layers and an optical bonding layer 140. In some embodiments, the light transmittance of the etching stop layer 137 to substantially perpendicular incident light is at least 50% for at least the first wavelength W1.

[0058] In some embodiments, the target wavelength(s) are within the visible range or the near-infrared range. Therefore, the first wavelength W1 may be in the range of 400 nm to 2500 nm. In some embodiments, the visible wavelength is the primary target. Therefore, the first wavelength W1 may be in the range of 400 nm to 700 nm. In some embodiments, the near-infrared wavelength is the primary target. Therefore, the first wavelength W1 may be, for example, in the range of 700 nm to 2500 nm or 800 nm to 2000 nm. Some specific near-infrared wavelengths that may be targeted depending on the application include, for example, 850 nm, 905 nm, 940 nm, 1060 nm, 1330 nm, and 1550 nm.

[0059] One or more patterned layers may contain any of the materials described elsewhere for one or more layers 135. In some embodiments, one or more patterned layers are or include one or more patterned inorganic layers. In some embodiments, one or more patterned layers contain silicon (e.g., one or more patterned layers may include one or more silicon layers). In some embodiments, one or more patterned layers may contain metal oxides (e.g., one or more patterned layers may include one or more metal oxide layers). In some embodiments, one or more patterned layers contain titania (e.g., one or more patterned layers may include one or more titania layers).

[0060] The etching stop layer 137 may be selected from a material having a desired light transmittance at the target wavelength for a suitable thickness. In some embodiments, the light transmittance of the etching stop layer 137 to substantially perpendicular incident light is at least 60%, or at least 70%, for at least a first wavelength W1. In some embodiments, the light transmittance of one or more unstructured layers to substantially perpendicular incident light is at least 60%, or at least 70%, for at least a first wavelength W1.

[0061] Figure 7 is a schematic cross-sectional view showing one or more unstructured layers 777, incident light 773, and transmitted light 774. The incident light 773 is incident substantially perpendicular (e.g., within 20 degrees, 10 degrees, or 5 degrees from perpendicular) to one or more unstructured layers 777, which may be a single layer (e.g., corresponding to any one of layers 131, 135, or 137) or a stack of layers (e.g., corresponding to layers 131, 135, or layers 135a, 135b). The incident light 773 is schematically represented as having a wavelength λ in the range λ1 to λ2. The range λ1 to λ2 may be, for example, 400 nm to 2500 nm, or 400 nm to 700 nm, or 700 nm to 2500 nm. The wavelength λ may be a single wavelength (e.g., a first wavelength W1) or a wavelength range (e.g., 400 nm to 700 nm). In some embodiments, the light transmittance of one or more unstructured layers 777 to substantially perpendicular incident light may be at least 60%, or at least 70%, or at least 80%, for at least a first wavelength W1. In some embodiments, the average light transmittance (unweighted average of light transmittances over a given wavelength range) of one or more unstructured layers 777 to substantially perpendicular incident light may be at least 50%, or at least 60%, or at least 70%, or at least 80%, for example, a wavelength range of 400 nm to 2500 nm or 400 nm to 700 nm.

[0062] Examples Structured film articles are prepared using nanoreplication, solvent coating, and vacuum thin-film deposition. The resulting structure is a laminate transfer film capable of delivering lithographic functional layers (patterned resist layer, hard mask layer, and etching stop layer) and unpatterned optical functional layers (titanium dioxide) to a receptor substrate such as a polished glass sheet.

[0063] These examples are for illustrative purposes only and are not intended to limit the scope of the invention. All parts, percentages, ratios, etc., in the examples and elsewhere in this specification are by weight unless otherwise indicated. The solvents and other reagents used are obtained from Sigma-Aldrich Chemical Company (St. Louis, Missouri) unless otherwise indicated.

[0064] [Table 1]

[0065] Preparation example Preparation example 1 (resin D) Acrylate resin mixture prepared by mixing PHOTOMER 6210, SR238, SR351, and TPO in a weight ratio of 60 / 20 / 20 / 0.5.

[0066] Hypothetical Example 1 The structured film article is formed by the following steps.

[0067] Step 1. Nano-replicating the template layer. A template film with nanofeatures is prepared by die-coating a polycarbonate film with resin D. The coated film is pressed onto a nanostructured nickel surface mounted on a steel roller controlled at 60°C using a rubber-coated roller at a speed of 15.2 meters / minute. The nanostructured nickel surface consists of 12 6mm × 6mm patterned regions with features ranging in size from 75nm to 500nm. The patterned regions consist of a multi-pitch pattern with pitches of 15nm, 200nm, and 250nm, and feature widths of half the pitch (75nm, 100nm, and 125nm).

[0068] The features are arranged within a square grid with varying pitches along both axes, resulting in nine repeating cells containing rectangles for all the aforementioned width combinations. In these repeating cells, the 150nm pitch section has 27 features, the 200nm pitch section has 20 features, and the 250nm pitch section has 16 features. The feature height is approximately 200nm, and the sidewall angle is approximately 4 degrees.

[0069] The coating thickness of resin D on the film is sufficient to completely wet the nickel surface and form rotating resin beads when the coated film is pressed against the nanostructured nickel surface. The film is exposed to radiation from two Fusion UV lamp systems (obtained from Fusion UV Systems (Gaithersburg, MD) under the trade name "F600"), both equipped with D bulbs and operating at 142 W / cm, while in contact with the nanostructured nickel surface. After peeling the film from the nanostructured nickel surface, the nanostructured side of the film is exposed again to radiation from the Fusion UV lamp systems.

[0070] Step 2. Solvent coating of the resist layer In Step 1, a solvent-based resin is coated onto sections of the template film containing nanofeatures using a slot-type coating die in a continuous film coating apparatus. The resin is selected to be compatible with the plasma etching process and to act as a resist for the plasma etching process. After coating, the coated web is moved approximately 2.4 m (8 ft) before being placed in a 9.1 m (30 ft) conventional air flotation dryer with all three zones set to 65.5°C (150°F). The dried resin layer is then planarized to fill the underlying template layer containing nanofeatures.

[0071] Step 3. Vacuum deposition of the hard mask layer A hard mask layer is formed on a resist-coated web surface by sputtering a 15 nm thick Cr layer using a roll-to-roll process. A single DC power supply controls the cathode housing a commercially available Cr target from Soleras Advanced Coatings (Spring Green, WI). This DC power supply drives a magnetron plasma onto the Cr target at a sputtering pressure in the range of 1–5 millitorre in an Ar-containing gas environment. The resist-coated web surface is rotated through the cathode at a speed appropriate for depositing the 15 nm thick Cr layer on top of the resist layer described above.

[0072] Step 4. Vacuum deposition of the titanium dioxide layer A thin film of TiO2 from titanium tetra(isopropoxide) (TTIP) is formed on the hard mask layer of the film obtained in the previous step using a spatial atomic layer deposition (ALD) process. Planar coating is performed using a spatial roll-to-roll ALD machine as described in U.S. Patent Application Publication No. 2019 / 0112711 (Lyons et al.). TiO2 is deposited using TTIP heated to 80°C with 300 sccm of N2 input gas and approximately 0.50 mA / cm². 2 Plasma discharge is used to deposit materials in an environment of 1.1 torr N2 and 0.3 torr CO2. The ALD chamber is heated to 100°C.

[0073] The film is moved parallel to the ALD chamber at a speed of 30.48 meters / min (100 feet / min) by passing it through the ALD chamber multiple times. Each ALD cycle involves one precursor exposure and one plasma exposure, resulting in 72 ALD cycles per chamber pass. The film is moved through the ALD chamber up to 50 times to obtain a TiO2 layer with a thickness of approximately 200 nm.

[0074] Step 5. Vacuum deposition of the etching stop layer. AlO2 is placed on top of the TiO2 layer formed in the previous step. xAn etching stop layer is formed by sputter deposition of the layers. A single AC power supply is used to control the cathodes housing two commercially available Al targets from Soleras Advanced Coatings (Spring Green, WI). During sputter deposition, the voltage signals from each power supply are used as inputs to a proportional-integral-differential control loop to maintain a predetermined oxygen flow to each cathode. The AC power supply uses 5000-16000 watts of power and drives a magnetron plasma onto the Al targets at a sputtering pressure in the range of 1-5 millitorr using a gas mixture containing argon and oxygen. The TiO2-coated web surface is then coated with a 12 nm thick AlO2 layer on top of the TiO2 layer described above. x The material is rotated through the cathode at a speed appropriate for depositing layers.

[0075] Step 6. Solution coating of the adhesive layer An adhesive layer is formed on the surface of the aforementioned etching stop layer by slot die coating with an adhesive coating solution using a roll-to-roll process. The adhesive coating solution is prepared by diluting a certain amount of FG1901 G in sufficient cyclohexane to produce a solution containing 0.33 wt% total solids. This solution is coated onto the film obtained in step 5 at a rate and flow rate that produces a wet coating thickness of approximately 9 micrometers. The coated web is moved approximately 2.4 m (8 ft) and then placed in a 9.1 m (30 ft) conventional air flotation dryer with all three zones set to 80°C (176°F). After drying, the thickness of the adhesive coating is approximately 30 nanometers.

[0076] Hypothetical Example 2 A laminated article is formed by laminating the structured film article of Hypothetical Example 1 onto a glass substrate. A suitable glass substrate is an Eagle XG glass wafer with a thickness of 1.1 mm and a diameter of 76.2 mm. The adhesive side of the structured film is placed on one surface of the glass wafer, and the film is laminated to the glass substrate by passing it through an HL-100 Hot Roll Laminator (ChemInstruments, West Chester Township, OH) set to 80 psi, 40 cm / min, and 115°C.

[0077] Hypothetical Example 3 Further processing of the laminate article in hypothetical example 2 forms a patterned substrate. By peeling the polycarbonate substrate together with the structured layer from the glass wafer, the template layer with nanofeatures is separated from the resist layer, and the template layer with nanofeatures is separated from the patterned resist resin layer.

[0078] Reactive ion etching is performed in a Plasmatherm 790 (Plasmatherm, Saint Petersburg, FL) configured with an inductively coupled power supply and capacitively coupled electrodes. After placing the patterned glass wafer on the energized electrodes, the reactor chamber is pumped down to a base pressure lower than 1.3 Pa (1 mTorr).

[0079] In the first etching step, residual land areas are removed from the nanostructured resin of Step 2 of Hypothetical Example 1. PF-5060 gas and O2 gas are flowed into the chamber at flow rates of 30 SCCM and 15 SCCM, respectively. A 13.56 MHz radio frequency (RF) power of 500 W is coupled to the capacitively coupled electrode. Plasma treatment is applied for 2 to 200 seconds, using the minimum processing time required to remove land areas from the nanostructured resist.

[0080] After the first etching step is complete, the RF power is turned off and the gas is evacuated from the chamber. In the second etching step, Cl2 gas and O2 gas are introduced into the reactor at flow rates of 38 SCCM and 2 SCCM, respectively. The pressure is maintained at 150 mTorr and capacitive RF power is applied at 350 W. Plasma treatment is applied for 15 to 60 seconds to transfer the pattern to the chrome hard mask layer.

[0081] Once the second etching step is complete, the RF power is turned off and the gas is discharged from the reactor. Following the second etching, the TiO2 layer is etched in a third reactive ion etching process performed in the same reactor without returning the chamber to atmospheric pressure. SF6 gas and Ar are flowed into the chamber at flow rates of 10 SCCM and 5 SCCM, respectively. 2 MHz RF power is coupled to the inductively coupled coil at 500 W, and 13.56 MHz RF power is coupled to the capacitively coupled electrode at 250 W. Plasma is applied for an exposure time of 80-150 seconds to transfer the pattern layer into the TiO2 layer without penetrating the etching stop layer. At the end of this process, the RF power and gas supply are stopped and the chamber is returned to atmospheric pressure.

[0082] Terms such as “about” will be understood by those skilled in the art in the context in which they are used and described herein. Where it is not otherwise obvious to those skilled in the art in the context in which they are used and described herein, the use of “about” in relation to quantities representing the size, volume, and physical properties of a functional part will be understood to mean within 10 percent of a particular value. A quantity given as about or approximately a particular value may be exactly that particular value. For example, where it is not otherwise obvious to those skilled in the art in the context in which it is used and described herein, a quantity having a value of about 1 means that the quantity has a value between 0.9 and 1.1, and that the value may also be 1.

[0083] All references, patents, or patent applications cited above are incorporated herein by reference in their entirety. In the event of any inconsistency or contradiction between any part of the incorporated references and this application, the information in the foregoing description shall prevail.

[0084] Unless otherwise indicated, the descriptions of elements in the drawings should be understood to apply equally to the corresponding elements in other drawings. While specific embodiments are illustrated and described herein, it will be understood by those skilled in the art that these specific embodiments may be replaced by various alternative and / or equivalent embodiments without departing from the scope of this disclosure. This application is intended to encompass any adaptation, modification, or combination of any specific embodiment discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents. The following are exemplary embodiments. [Item 1] A structured film for forming a pattern on a substrate, Polymeric support layer, Adhesive layer, An etching resist layer disposed between the polymeric support layer and the adhesive layer, A structured resin layer disposed between the polymeric support layer and the etching resist layer, wherein the structured resin layer comprises a structured main surface having a plurality of processed structures, and the etching resist layer substantially flattens the structured main surface by at least partially filling the spaces between adjacent processed structures. One or more unstructured layers having a total thickness of less than 10 micrometers are disposed between the etching resist layer and the adhesive layer, A structured film equipped with [a specific feature]. [Item 2] The structured film according to item 1, wherein the structured resin layer is peelably attached to the polymeric support layer or the etching resist layer. [Item 3] The structured film according to item 1, further comprising a dynamic separation layer disposed between the structured resin layer and the polymeric support layer. [Item 4] A structured film according to any one of items 1 to 3, wherein the etching resist layer comprises a residual layer between the substantially unstructured main surface of the etching resist layer and the plurality of processed structures, and the ratio of the average thickness of the residual layer to the average height of the plurality of processed structures is less than 1. [Item 5] The structured film according to any one of items 1 to 4, wherein the plurality of processed structures have at least two different heights. [Item 6] A structured film according to any one of items 1 to 5, wherein the aforementioned multiple processed structures comprise multiple nanostructures. [Item 7] The structured film according to any one of items 1 to 6, wherein the one or more unstructured layers comprise at least two unstructured layers. [Item 8] A method for forming a pattern on a substrate, Polymeric support layer, One or more unstructured layers, An etching resist layer disposed between the polymeric support layer and the one or more unstructured layers, A structured resin layer disposed between the polymeric support layer and the etching resist layer, wherein the structured resin layer comprises a structured main surface having a plurality of processed structures, and the etching resist layer at least partially fills the spaces between adjacent processed structures, substantially flattening the structured main surface and defining the etching resist pattern, To provide a structured film having the following features: The structured film is bonded to the substrate such that the polymeric support layer is oriented away from the substrate, Removing at least the polymeric support layer while leaving at least the etching resist layer and one or more unstructured layers disposed on the substrate, The etching resist pattern is transferred to one or more unstructured layers, thereby etching into the one or more unstructured layers to form the pattern on the substrate. A method that includes the following in order. [Item 9] The method according to item 8, wherein the structured film comprises an adhesive layer disposed on one or more unstructured layers, and joining the structured film to the substrate includes bonding the structured film to the substrate using the adhesive layer. [Item 10] The method according to item 8 or 9, wherein etching into the one or more unstructured layers includes etching through the etching resist layer into the one or more unstructured layers. [Item 11] The structured film further comprises a mask layer disposed between the one or more unstructured layers and the etching resist layer, and etching into the one or more unstructured layers is performed. In the first etching step, the etching resist layer is penetrated and a portion of the mask layer is etched to form a patterned mask layer, The process includes etching through the patterned mask layer into one or more unstructured layers in a second etching step to form the pattern on the substrate, The method described in item 8 or 9. [Item 12] Substrate and An optically transparent etching stop layer disposed on the substrate, A structured film disposed on the etching stop layer, comprising one or more patterned layers and an adhesive layer for bonding the one or more patterned layers to the etching stop layer, An optical article comprising, The structured film comprises a plurality of structures that define a plurality of voids separating adjacent structures, and at least some of the voids penetrate the structured film and extend to the etching stop layer. Optical articles. [Item 13] The optical article according to item 12, wherein the average thickness of the adhesive layer is less than 100 nm. [Item 14] The optical article according to item 12 or 13, wherein the one or more patterned layers comprise a patterned inorganic layer. [Item 15] Waveguides and An optical article comprising a structured film disposed on the waveguide, wherein the structured film is An optical bonding layer that joins the structured film to the waveguide, One or more patterned layers disposed on the optical bonding layer, wherein the one or more patterned layers are formed by patterning one or more unstructured layers, and the light transmittance of the one or more unstructured layers to substantially perpendicular incident light is at least 50% for a first wavelength W1 in the range of at least 400 nm to 2500 nm, An etching stop layer disposed between the one or more patterned layers and the optical bonding layer, wherein the light transmittance of the etching stop layer to substantially perpendicular incident light is at least 50% for at least the first wavelength W1, and the etching stop layer comprises The refractive index of the optical bonding layer has an imaginary part less than 0.1 for at least the first wavelength W1, and the average thickness of the optical bonding layer is greater than 5 nm and less than 1 / 4 W1. Optical articles.

Claims

1. A structured film for forming a pattern on a substrate, Polymeric support layer, Adhesive layer, An etching resist layer disposed between the polymeric support layer and the adhesive layer, A structured resin layer disposed between the polymeric support layer and the etching resist layer, wherein the structured resin layer comprises a structured main surface having a plurality of processed structures, and the etching resist layer substantially flattens the structured main surface by at least partially filling the spaces between adjacent processed structures. A dynamic separation layer disposed between the structured resin layer and the polymeric support layer, Displaced between the etching resist layer and the adhesive layer, one or more unstructured layers having a total thickness of less than 10 micrometers and lacking a structured main surface, Equipped with, The dynamic separation layer is a layer that can change from a first state to at least a second state, in the first state the dynamic separation layer has high adhesion to at least one adjacent layer, and in the second state the dynamic separation layer has low adhesion to at least one adjacent layer. Structured film.

2. The structured film according to claim 1, wherein the structured resin layer is permanently attached to the etching resist layer.

3. The structured film according to claim 1, wherein the dynamic separation layer comprises a photothermal conversion layer.

4. The structured film according to any one of claims 1 to 3, wherein the etching resist layer comprises a residual layer between the substantially unstructured main surface of the etching resist layer and the plurality of processed structures, and the ratio of the average thickness of the residual layer to the average height of the plurality of processed structures is less than 1.

5. The structured film according to any one of claims 1 to 3, wherein the plurality of processed structures have at least two different heights.

6. The structured film according to any one of claims 1 to 3, wherein the plurality of processed structures comprises a plurality of nanostructures.

7. The structured film according to any one of claims 1 to 3, wherein the one or more unstructured layers comprises at least two unstructured layers.

8. An additional polymer layer is further provided between the dynamic separation layer and the structured resin layer, The dynamic separation layer is adapted to be detachably attached to the additional polymer layer upon activation. A structured film according to any one of claims 1 to 3.

9. A manufacturing method for forming a pattern on a substrate, Polymeric support layer, One or more unstructured layers that do not have a structured main surface, An etching resist layer disposed between the polymeric support layer and the one or more unstructured layers, A structured resin layer disposed between the polymeric support layer and the etching resist layer, wherein the structured resin layer comprises a structured main surface having a plurality of processed structures, and the etching resist layer at least partially fills the spaces between adjacent processed structures, substantially flattening the structured main surface and defining the etching resist pattern, A dynamic separation layer disposed between the structured resin layer and the polymeric support layer, Equipped with, The dynamic separation layer is a layer that can change from a first state to at least a second state, in the first state the dynamic separation layer has high adhesion to at least one adjacent layer, and in the second state the dynamic separation layer has low adhesion to at least one adjacent layer. To provide a structured film, The structured film is bonded to the substrate such that the polymeric support layer is oriented away from the substrate, Removing at least the polymeric support layer while leaving at least the etching resist layer, the structured resin layer, and one or more unstructured layers arranged on the substrate, The etching resist pattern is transferred to one or more unstructured layers, thereby etching into the one or more unstructured layers to form the pattern on the substrate. It includes in order, Further comprising activating the dynamic separation layer at least before removing the polymeric support layer, Manufacturing method.

10. The manufacturing method according to claim 9, wherein the structured film comprises an adhesive layer disposed on one or more unstructured layers, and joining the structured film to the substrate includes bonding the structured film to the substrate using the adhesive layer.

11. The manufacturing method according to claim 9 or 10, wherein etching into one or more unstructured layers includes etching through the etching resist layer into one or more unstructured layers.

12. The structured film further comprises a mask layer disposed between the one or more unstructured layers and the etching resist layer, and etching into the one or more unstructured layers is performed. In the first etching step, the etching resist layer is penetrated and a portion of the mask layer is etched to form a patterned mask layer, The process includes etching through the patterned mask layer into one or more unstructured layers in a second etching step to form the pattern on the substrate, The manufacturing method according to claim 9 or 10.

13. Activating the dynamic separation layer includes irradiating the dynamic separation layer. The manufacturing method according to claim 9 or 10.

14. A structured film for forming a pattern on a substrate, Polymeric support layer, Adhesive layer, An etching resist layer disposed between the polymeric support layer and the adhesive layer, A structured resin layer disposed between the polymeric support layer and the etching resist layer, wherein the structured resin layer comprises a structured main surface having a plurality of processed structures, and the etching resist layer substantially flattens the structured main surface by at least partially filling the spaces between adjacent processed structures. Displaced between the etching resist layer and the adhesive layer, one or more unstructured layers having a total thickness of less than 10 micrometers and lacking a structured main surface, Equipped with, A structured film in which the structured resin layer is permanently attached to the etching resist layer and peelably attached to the polymeric support layer.

15. The structured film according to claim 14, wherein the plurality of processed structures have at least two different heights.

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