Optical metasurface structure and method of manufacturing the same

Abstract

An optical metasurface structure and a method for fabricating the same are disclosed. The optical metasurface structure includes a substrate, a plurality of metal track structures, and a liquid crystal material. The substrate includes a first region and a second region. The plurality of metal track structures and the liquid crystal material are disposed on the first region. At least a portion of the liquid crystal material is located between adjacent metal track structures in a horizontal direction. An upper portion of one of the plurality of metal track structures has a width that is less than a width of a bottom portion of the one of the plurality of metal track structures.

Description

Technical Field

[0001] This invention relates to an optical metasurface structure and its fabrication method, and more particularly to an optical metasurface structure including a metal track structure and its fabrication method. Background Technology

[0002] Optical metasurfaces can alter many properties of incident radiation (e.g., incident light rays) (e.g., amplitude, phase, and / or polarization), thereby enabling various specific functions (e.g., beam manipulation, focusing, spectral filtering, etc.). By combining liquid crystal materials with the design of applied voltage conditions, tunable optical metasurfaces can be realized, thus expanding the application range of optical metasurfaces. Summary of the Invention

[0003] This invention provides an optical metasurface structure and its fabrication method, which utilizes a metal track structure with an upper width smaller than the bottom width in combination with liquid crystal material to realize a tunable optical metasurface structure.

[0004] An embodiment of the present invention provides an optical metasurface structure, including a substrate, a plurality of metal track structures, and a liquid crystal material. The substrate includes a first region and a second region. The plurality of metal track structures and the liquid crystal material are disposed on the first region, at least a portion of the liquid crystal material is located between adjacent metal track structures in a horizontal direction, and the upper width of one of the plurality of metal track structures is smaller than the bottom width of the same metal track structure.

[0005] An embodiment of the present invention provides a method for fabricating an optical metasurface structure, comprising the following steps: providing a substrate, the substrate including a first region and a second region; forming a plurality of metal track structures on the first region, and forming a liquid crystal material on the first region; at least a portion of the liquid crystal material being located between adjacent metal track structures in a horizontal direction, and the upper width of one of the plurality of metal track structures being smaller than the bottom width of the metal track structure. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the optical metasurface structure according to the first embodiment of the present invention;

[0007] Figure 2 This is a schematic diagram illustrating the operational status of an optical metasurface structure according to an embodiment of the present invention;

[0008] Figures 3 to 9 This is a schematic diagram of the fabrication method of the optical metasurface structure according to the first embodiment of the present invention, wherein...

[0009] Figure 4for Figure 3 A diagram illustrating the subsequent situation;

[0010] Figure 5 for Figure 4 A diagram illustrating the subsequent situation;

[0011] Figure 6 for Figure 5 A diagram illustrating the subsequent situation;

[0012] Figure 7 for Figure 6 A diagram illustrating the subsequent situation;

[0013] Figure 8 for Figure 7 A diagram illustrating the subsequent situation;

[0014] Figure 9 for Figure 8 A diagram illustrating the subsequent situation.

[0015] Figure 10 This is a schematic diagram of the optical metasurface structure according to the second embodiment of the present invention;

[0016] Figure 11 This is a schematic diagram of the fabrication method of the optical metasurface structure according to the second embodiment of the present invention;

[0017] Figure 12 This is a schematic diagram of the optical metasurface structure according to the third embodiment of the present invention;

[0018] Figure 13 and Figure 14 This is a schematic diagram of the fabrication method of the optical metasurface structure according to the third embodiment of the present invention, wherein... Figure 14 for Figure 13 A diagram illustrating the subsequent situation;

[0019] Figure 15 This is a schematic diagram of the optical metasurface structure according to the fourth embodiment of the present invention.

[0020] Symbol Explanation

[0021] 22: Base

[0022] 24: Dielectric layer

[0023] 26: Etching Stop Layer

[0024] 28: Dielectric layer

[0025] 30: Barrier Layer

[0026] 32: Conductive materials

[0027] 34: Etching Stop Layer

[0028] 36: Dielectric layer

[0029] 38: Etching Stop Layer

[0030] 40: Barrier Layer

[0031] 42: Conductive materials

[0032] 44: Patterned barrier layer

[0033] 44A: First obstacle pattern

[0034] 44B: Second obstacle pattern

[0035] 44M: Barrier Material Layer

[0036] 46: Patterned copper layer

[0037] 46A: First Bronze Pattern

[0038] 46B: Second bronze pattern

[0039] 46M: Copper layer

[0040] 48: Patterned metallic mask layer

[0041] 48A: First metal mask pattern

[0042] 48B: Second metal mask pattern

[0043] 48M: Metal mask layer

[0044] 50: Patterned mask layer

[0045] 60: Dielectric capping layer

[0046] 70: Packaging materials

[0047] 80: Cover plate

[0048] 90: Patterned production process

[0049] 101: Optical Metasurface Structure

[0050] 102: Optical Metasurface Structure

[0051] 103: Optical Metasurface Structure

[0052] 104: Optical Metasurface Structure

[0053] BP: Joint pad

[0054] BS: Bottom surface

[0055] BS1: Bottom surface

[0056] BS2: Bottom surface

[0057] BS3: Bottom surface

[0058] BS4: Bottom surface

[0059] CS: Connection Structure

[0060] D1: Vertical direction

[0061] D2: Horizontal direction

[0062] L1: Light

[0063] L2: Light

[0064] L3: Light

[0065] LC: Liquid Crystal Material

[0066] M1: Wire

[0067] OP: Open

[0068] R1: Zone 1

[0069] R2: Second Zone

[0070] RC1: Depression

[0071] RC2: Depression

[0072] RS: Metal Track Structure

[0073] SP: Spacer

[0074] SW: Sidewall

[0075] TS1: Top surface

[0076] TS2: Top surface

[0077] TS3: Top surface

[0078] TS4: Top surface

[0079] TS5: Top surface

[0080] V1: Through-hole conductor

[0081] W1: Width

[0082] W2: Width

[0083] W3: Width

[0084] W4: Width

[0085] WB: Joining copper wire Detailed Implementation

[0086] The following detailed description of the invention discloses sufficient detail to enable those skilled in the art to practice it. The embodiments described below should be considered illustrative rather than restrictive. It will be apparent to those skilled in the art that various changes and modifications in form and detail can be made without departing from the spirit and scope of the invention.

[0087] Before further describing the various embodiments, the following will explain the specific terms used throughout the text.

[0088] The meanings of the terms “on,” “above,” and “on top of” should be interpreted in the broadest sense, such that “on” means not only “directly on” something but also includes something with other intervening features or layers in between, and that “above” or “on top of” means not only “above” or “on top of” something but can also include something “above” or “on top of” without other intervening features or layers in between (i.e., directly on something).

[0089] The ordinal numbers used in the specification and claims, such as "first" and "second", are used to modify the elements of the claims. Unless otherwise specified, they do not imply or represent any prior ordinal number of the claimed element, nor do they represent the order of one claimed element with another, or the order of manufacturing methods. The use of these ordinal numbers is only to enable a claim element with a certain name to be clearly distinguished from another claim element with the same name.

[0090] The term "etching" is generally used herein to describe a fabrication process for patterning material such that at least a portion of the material is left after etching. When a material is "etched," at least a portion of the material is retained after etching. Conversely, when a material is "removed," essentially all of the material can be removed during the process. However, in some embodiments, "removal" can be considered a broad term that includes etching.

[0091] The terms “forming” or “setting” are used below to describe the behavior of applying a layer of material to a substrate. These terms are intended to describe any feasible layer forming technique, including but not limited to thermal growth, sputtering, evaporation, chemical vapor deposition, epitaxial growth, electroplating, etc.

[0092] Please see Figure 1 . Figure 1 The illustration shows a schematic diagram of the optical metasurface structure 101 according to a first embodiment of the present invention. Figure 1As shown, the optical metasurface structure 101 includes a substrate 22, a plurality of metal track structures RS, and a liquid crystal material LC. The substrate 22 includes a first region R1 and a second region R2. The plurality of metal track structures RS and the liquid crystal material LC are disposed on the first region R1. At least a portion of the liquid crystal material LC is located between adjacent metal track structures RS in a horizontal direction D2, and the upper width (e.g., width W2) of at least one of the plurality of metal track structures RS is smaller than the bottom width (e.g., width W1) of this metal track structure RS. In some embodiments, the upper width of each metal track structure RS may be smaller than the bottom width of this metal track structure RS. A tunable optical metasurface structure can be realized by using metal track structures RS with an upper width smaller than a bottom width in combination with liquid crystal material LC.

[0093] In some embodiments, a vertical direction D1 can be considered as the thickness direction of the substrate 22. The substrate 22 may have an upper surface and a bottom surface BS opposite each other in the vertical direction D1, and the aforementioned metal track structure RS and liquid crystal material LC may be disposed on one side of the upper surface. A horizontal direction that is substantially orthogonal to the vertical direction D1 (e.g., horizontal direction D2 and other directions orthogonal to the vertical direction D1) may be substantially parallel to the bottom surface BS of the substrate 22, but is not limited thereto. In this document, the distance in the vertical direction D1 between a relatively high position and / or between a component and the bottom surface BS of the base 22 may be greater than the distance in the vertical direction D1 between a relatively low position and / or between a component and the bottom surface BS of the base 22. The lower part or bottom of each component may be closer to the bottom surface BS of the base 22 in the vertical direction D1 than the upper part or top of that component. Another component above a certain component may be considered relatively far from the bottom surface BS of the base 22 in the vertical direction D1, while another component below a certain component may be considered relatively close to the bottom surface BS of the base 22 in the vertical direction D1. Furthermore, the upper surface and upper part of a specific component may respectively include the topmost surface and the uppermost part of that component in the vertical direction D1, and the bottom surface and bottom of a specific component may respectively include the bottommost surface and the bottommost part of that component in the vertical direction D1. The situation in which a specific component is disposed between two other objects in a certain direction may include, but is not limited to, the situation where the component is sandwiched between these two objects in this direction.

[0094] In some embodiments, substrate 22 may include a silicon substrate or a substrate formed of other suitable semiconductor or non-semiconductor materials. Furthermore, the first region R1 and the second region R2 of substrate 22 may be considered as a metal track region and a surrounding bonding region, respectively, but are not limited thereto. In some embodiments, the optical metasurface structure 101 may further include a bonding pad BP, a dielectric layer (e.g., dielectric layer 24, etch stop layer 26, dielectric layer 28, etch stop layer 34, dielectric layer 36, and / or etch stop layer 38), and a connection structure CS. The bonding pad BP is disposed on the second region R2, and the material composition of the bonding pad BP may be the same as the material composition of each metal track structure RS. Dielectric layer 24, etch stop layer 26, dielectric layer 28, etch stop layer 34, dielectric layer 36, and etch stop layer 38 may be sequentially stacked on the first region R1 and the second region R2 of the substrate 22 in the vertical direction D1, and the connection structure CS may be disposed in the dielectric layer 24, etch stop layer 26, dielectric layer 28, etch stop layer 34, dielectric layer 36, and etch stop layer 38. Dielectric layer 24, dielectric layer 28, and dielectric layer 36 may respectively include oxide dielectric materials (e.g., silicon oxide) or other suitable dielectric materials, while etch stop layer 26, etch stop layer 34, and etch stop layer 38 may respectively include nitride dielectric materials, carbide dielectric materials (e.g., nitrogen-doped carbide, NDC), or other suitable dielectric materials.

[0095] In some embodiments, the connection structure CS may include multiple conductors M1 and multiple via conductors V1. Each conductor M1 may be disposed in the dielectric layer 24, the etch stop layer 26, and the dielectric layer 28, while the via conductors V1 may be disposed in the etch stop layer 34, the dielectric layer 36, and the etch stop layer 38. Each via conductor V1 may be disposed on the corresponding conductor M1 in the vertical direction D1 and directly contact the conductor M1 to form an electrical connection. The bonding pad BP and multiple metal track structures RS may be disposed on the dielectric layer (e.g., dielectric layer 24, etch stop layer 26, dielectric layer 28, etch stop layer 34, dielectric layer 36, and etch stop layer 38) and the connection structure CS in the vertical direction D1, and the bonding pad BP may be electrically connected to at least one of the multiple metal track structures RS through the connection structure CS. In some embodiments, each conductor M1 may include a barrier layer 30 and a conductive material 32 disposed on the barrier layer 30, while the via conductor V1 may include a barrier layer 40 and a conductive material 42 disposed on the barrier layer 40, but is not limited thereto. The barrier layer 30 and the barrier layer 40 may respectively include titanium, titanium nitride, tantalum, tantalum nitride or other suitable conductive barrier materials, while the conductive material 32 and the conductive material 42 may respectively include materials with relatively low resistivity such as copper, aluminum, tungsten, etc.

[0096] In some embodiments, the visual design requires the placement of active (e.g., transistors, diodes, etc.), passive (e.g., capacitors, resistors, etc.), and / or related circuitry (not shown) on the substrate 22. Bonding pads BP and / or metal track structures RS can be electrically connected to these elements and / or circuitry via a connection structure CS. The potential of each metal track structure RS can be controlled by specific elements and / or circuitry, but this is not a limitation. In some embodiments, the dielectric layer 24 and the substrate 22 may have the same material composition and can be considered as a single substrate structure. The dielectric layer 24 and the substrate 22 may not contain the aforementioned elements and / or circuitry. Multiple bonding pads BP can be placed on the second region R2. Each bonding pad BP can be electrically connected to its corresponding metal track structure RS via a connection structure CS, thereby controlling the potential of each metal track structure RS.

[0097] In some embodiments, each metal track structure RS may include a first barrier pattern 44A, a first copper pattern 46A, and a first metal mask pattern 48A stacked sequentially in the vertical direction D1, and the bonding pad BP may include a second barrier pattern 44B, a second copper pattern 46B, and a second metal mask pattern 48B stacked sequentially in the vertical direction D1. The first copper pattern 46A is disposed on the first barrier pattern 44A, the second copper pattern 46B is disposed on the second barrier pattern 44B, the first metal mask pattern 48A is disposed on the first copper pattern 46A, and the second metal mask pattern 48B is disposed on the second copper pattern 46B. In some embodiments, the first copper pattern 46A may directly contact the first barrier pattern 44A and the first metal mask pattern 48A, respectively, and the second copper pattern 46B may directly contact the second barrier pattern 44B and the second metal mask pattern 48B, respectively, but this is not a limitation. Furthermore, the first barrier pattern 44A and the second barrier pattern 44B can be different, separate portions of a patterned barrier layer 44, and therefore the first barrier pattern 44A and the second barrier pattern 44B can have the same material composition; the first copper pattern 46A and the second copper pattern 46B can be different, separate portions of a patterned copper layer 46, and therefore the first copper pattern 46A and the second copper pattern 46B can have the same material composition; the first metal mask pattern 48A and the second metal mask pattern 48B can be different, separate portions of a patterned metal mask layer 48, and therefore the first metal mask pattern 48A and the second metal mask pattern 48B can have the same material composition. In some embodiments, the patterned barrier layer 44 may include tantalum, tantalum nitride, or other suitable conductive barrier materials, the patterned copper layer 46 may be composed of copper, and the patterned metal mask layer 48 may include titanium nitride, tantalum nitride, aluminum, or other suitable metal mask materials.

[0098] In some embodiments, cross-sectional views of each metal track structure RS in the optical metasurface structure 101 (e.g.) Figure 1 The structure may have a trapezoidal structure that is narrow at the top and wide at the bottom. The width of each metal track structure RS may gradually or / and continuously increase from the upper surface (e.g., upper surface TS3) to the bottom surface BS1. The first barrier pattern 44A, the first copper pattern 46A and the first metal mask pattern 48A in each metal track structure RS may also have a trapezoidal structure that is narrow at the top and wide at the bottom in the cross-sectional view of the optical metasurface structure 101, but this is not a limitation. Therefore, the upper width of each first metal mask pattern 48A (e.g., the length of the upper surface TS3 in the horizontal direction D2) can be smaller than the bottom width of the first metal mask pattern 48A (e.g., the length of the bottom surface BS3 in the horizontal direction D2), the upper width of each first copper pattern 46A (e.g., the length of the upper surface TS2 in the horizontal direction D2) can be smaller than the bottom width of the first copper pattern 46A (e.g., the length of the bottom surface BS2 in the horizontal direction D2), and the upper width of each first barrier pattern 44A (e.g., the length of the upper surface TS1 in the horizontal direction D2) can be smaller than the bottom width of the first barrier pattern 44A (e.g., the length of the bottom surface BS1 in the horizontal direction D2). In some embodiments, at least a portion of each metal track structure RS can extend substantially along another horizontal direction (e.g., a horizontal direction orthogonal to the horizontal direction D2 and the vertical direction D1, respectively), and the length of each metal track structure RS in the horizontal direction D2 can be considered as the aforementioned width, but is not limited thereto. Furthermore, the bottom surface of the bonding pad BP (e.g., bottom surface BS4) and the bottom surface of each metal track structure RS (e.g., bottom surface BS1) may be substantially coplanar, and the upper surface of the bonding pad BP (e.g., upper surface TS4) and the upper surface of each metal track structure RS (e.g., upper surface TS3) may be substantially coplanar. In some embodiments, the bottom width (e.g., width W1) of each metal track structure RS may be greater than the upper width of the corresponding via conductor V1, in order to avoid or reduce the negative impact of the fabrication process of forming the metal track structure RS on the via conductor V1.

[0099] In some embodiments, the optical metasurface structure 101 may further include a dielectric capping layer 60 disposed on a plurality of metal track structures RS and bonding pad BP. The dielectric capping layer 60 may cover the upper surface and sidewalls of each metal track structure RS and the upper surface and sidewalls of the bonding pad BP, and a portion of the dielectric capping layer 60 may be sandwiched between the liquid crystal material LC and each metal track structure RS. A portion of the dielectric capping layer 60 may be disposed on the sidewalls (e.g., sidewall SW) of the first barrier pattern 44A, the sidewalls of the first copper pattern 46A, and the sidewalls and upper surface TS3 of the first metal mask pattern 48A of each metal track structure RS, and directly contact the sidewalls SW, SW, TS3 of the first barrier pattern 44A, the sidewalls of the first copper pattern 46A, and the sidewalls and upper surface TS3 of the first metal mask pattern 48A. Another portion of the dielectric capping layer 60 may be disposed on the sidewalls of the second barrier pattern 44B, the second copper pattern 46B, and the second metal mask pattern 48B of the bonding pad BP, and on the upper surface TS4, directly contacting the sidewalls of the second barrier pattern 44B, the second copper pattern 46B, and the second metal mask pattern 48B. The dielectric capping layer 60 may include silicon nitride or other suitable dielectric materials. In some embodiments, the optical metasurface structure 101 may further include an opening OP, a bonding copper wire WB, and an encapsulation material 70. The opening OP may penetrate the dielectric capping layer 60 located on the bonding pad BP and the second metal mask pattern 48B in the bonding pad BP to expose the second copper pattern 46B in the bonding pad BP. The bonding copper wire WB may be partially disposed in the opening OP and directly connected to the second copper pattern 46B. The encapsulation material 70 may be disposed on the second region R2 and cover the dielectric capping layer 60, the bonding pad BP, and the bonding copper wire WB. The encapsulation material 70 may include epoxy resin or other suitable materials.

[0100] Please see Figure 2 . Figure 2 The illustration shows the operational status of an optical metasurface structure according to an embodiment of the present invention. Figure 2As shown, in some embodiments, the arrangement of liquid crystal molecules in the liquid crystal material LC can be controlled by adjusting the voltage applied to each metal track structure RS, thereby changing the angle of reflected light when the metal track structure RS and the liquid crystal material LC reflect incident light. For example, when there is a first voltage difference between adjacent metal track structures RS, the incident light (e.g., light L1) can be reflected to become light L2. When the voltage applied to the metal track structures RS is changed to create a second voltage difference between adjacent metal track structures RS, the incident light (e.g., light L1) can be reflected to become light L3 with a larger reflection angle, but this is not a limitation. By adjusting the voltage applied to each metal track structure RS, the optical metasurface structure of the present invention can be used to reflect incident light with different angles into reflected light with a specific angle and / or reflect incident light with a specific angle into reflected light with different angles. Therefore, the optical metasurface structure of the present invention can be considered as a tunable optical metasurface structure. In some embodiments, the optical metasurface structure of the present invention can be applied in a LiDAR structure in conjunction with a detection light emitter (e.g., but not limited to an infrared laser emitter) to reflect the detection light into multiple rays with different emission angles, thereby increasing the angular range of the detection light emitted by the LiDAR structure. The optical metasurface structure can also be used in conjunction with a detection light receiver to reflect received light from different angles to a detection light receiver with a fixed position. In some embodiments, the extent of the conductor M1 and / or the metal conductive pattern (not shown) on the same layer as the conductor M1 can be adjusted to enhance the reflection effect of the optical metasurface structure on specific rays. Furthermore, the width, height, length of each metal track structure RS, and the spacing between adjacent metal track structures RS can be adjusted according to the wavelength range of the corresponding operating light to produce the desired resonance effect. For example, the spacing between the metal track structures RS can be smaller than the wavelength of the operating light, but is not limited thereto.

[0101] Please see Figure 1 as well as Figures 3 to 9 . Figures 3 to 9 The illustration shows a schematic diagram of the fabrication method of the optical metasurface structure according to the first embodiment of the present invention, wherein... Figure 4 It is illustrated Figure 3 A diagram illustrating the subsequent situation. Figure 5 It is illustrated Figure 4 A diagram illustrating the subsequent situation. Figure 6 It is illustrated Figure 5 A diagram illustrating the subsequent situation. Figure 7 It is illustrated Figure 6 A diagram illustrating the subsequent situation. Figure 8 It is illustrated Figure 7 The following is a diagram illustrating the situation, and Figure 9 It is illustrated Figure 8A schematic diagram of the subsequent situation. In some embodiments, Figure 1 It can be regarded as a drawing Figure 9 The following is a schematic diagram of the situation, but it is not limited to this. For example... Figure 1 As shown, the fabrication method of this embodiment includes the following steps. First, a substrate 22 is provided, and the substrate 22 includes a first region R1 and a second region R2. A plurality of metal track structures RS are formed on the first region R1, and a liquid crystal material LC is formed on the first region R1. At least a portion of the liquid crystal material LC is located between adjacent metal track structures RS in the horizontal direction D2, and the upper width (e.g., width W2) of at least one of the plurality of metal track structures RS is smaller than the bottom width (e.g., width W1) of this metal track structure RS.

[0102] To further explain, the manufacturing method of this embodiment may include, but is not limited to, the following steps. For example... Figure 3 As shown, before the aforementioned metal track structure and bonding pad are formed, dielectric layers (e.g., dielectric layer 24, etch stop layer 26, dielectric layer 28, etch stop layer 34, dielectric layer 36, or / and etch stop layer 38) can be formed on the first region R1 and the second region R2 of the substrate 22, and an interconnection structure CS can be formed in the dielectric layers. After the aforementioned dielectric layers and interconnection structure CS are formed, a barrier material layer 44M and a copper layer 46M can be sequentially formed on the first region R1 and the second region R2 of the substrate 22. The barrier material layer 44M can be formed on the upper surface of the etch stop layer 38 and the via conductor V1, and the copper layer 46M can be formed on the barrier material layer 44M. In some embodiments, a copper material can be formed on the barrier material layer 44M by electrochemical plating (ECP) or other suitable fabrication processes, and the copper material can be planarized to form the copper layer 46M, but this is not a limitation. Then, as Figure 4 As shown, a metal mask layer 48M can be formed on the copper layer 46M, and the metal mask layer 48M can be partially located above the first region R1 and partially located above the second region R2 in the vertical direction D1. Figure 4 and Figure 5 As shown, after the metal mask layer 48M is formed, a patterned mask layer 50 can be formed on the metal mask layer 48M, and a patterning fabrication process 90 is performed using the patterned mask layer 50 as a mask. The patterned mask layer 50 may include a photoresist or other suitable mask material, and the patterning fabrication process 90 may include an ion beam etching (IBE) fabrication process or other suitable patterning methods.

[0103] like Figure 5 and Figure 6As shown, the patterned mask layer 50 can be removed after the patterning fabrication process 90. The metal mask layer 48M can be patterned by the patterning fabrication process 90 to become a patterned metal mask layer 48, the copper layer 46M can be patterned by the patterning fabrication process 90 to become a patterned copper layer 46, and the barrier material layer 44M can be patterned by the patterning fabrication process 90 to become a patterned barrier layer 44. The patterned metal mask layer 48 may include a plurality of first metal mask patterns 48A located on a first region R1 and a second metal mask pattern 48B located on a second region R2. The patterned copper layer 46 includes a plurality of first copper patterns 46A located on a first region R1 and a second copper pattern 46B located on a second region R2. The patterned barrier layer 44 includes a plurality of first barrier patterns 44A located on a first region R1 and a second barrier pattern 44B located on a second region R2. Each metal track structure RS may include one of a plurality of first metal mask patterns 48A, one of a plurality of first copper patterns 46A, and one of a plurality of first barrier patterns 44A, while the bonding pad BP may include a second metal mask pattern 48B, a second copper pattern 46B, and a second barrier pattern 44B. In some embodiments, the patterning process 90 may remove at least a portion of the metal mask layer 48M, copper layer 46M, and barrier material layer 44M that are not covered by the patterned mask layer 50 in the vertical direction D1 to achieve a patterning effect, and a portion of the etch stop layer 38 may be removed by the patterning process 90 to form a recess RC1 located between adjacent metal track structures RS and a recess RC2 located between the bonding pad BP and the metal track structure RS, but is not limited thereto. In other words, the bottom of recess RC1 (e.g., the upper surface of etch stop layer 38 located below recess RC1) and the bottom of recess RC2 (e.g., the upper surface of etch stop layer 38 located below recess RC2) may be lower in the vertical direction D1 than the upper surface of etch stop layer 38 located below metal track structure RS and the upper surface of etch stop layer 38 located below bonding pad BP.

[0104] Metal track structures RS and bonding pads BP can be formed on the first region R1 and the second region R2 respectively using a patterning process 90. The material composition of the bonding pads BP is the same as that of each metal track structure RS, and the bonding pads BP and multiple metal track structures RS can be considered to be formed together using the same manufacturing process. It is worth noting that the method for forming the metal track structures RS and bonding pads BP in this embodiment may include, but is not limited to, the above-described method. Figures 3 to 6 The steps shown can be adapted to other suitable methods as required by the design. Figure 6The metal track structure RS and bonding pad BP are shown. Due to the fabrication process characteristics of the patterning process 90 (e.g., the fabrication process characteristics of the IBE process), each metal track structure RS may have a trapezoidal structure that is narrower at the top and wider at the bottom in cross-sectional view. The upper width (e.g., width W2) of each first metal mask pattern 48A may be smaller than the bottom width (e.g., width W4) of the first metal mask pattern 48A, the upper width (e.g., width W4) of each first copper pattern 46A may be smaller than the bottom width (e.g., width W3) of the first copper pattern 46A, and the upper width of each first barrier pattern 44A may be smaller than the bottom width of the first barrier pattern 44A, but these are not limitations. Furthermore, the metal track structure RS and bonding pad BP may be formed on a dielectric layer (e.g., dielectric layer 24, etch stop layer 26, dielectric layer 28, etch stop layer 34, dielectric layer 36 and / or etch stop layer 38) and a connection structure CS, and the bonding pad BP may be electrically connected to at least one of the plurality of metal track structures RS through the connection structure CS.

[0105] After that, as Figure 7 As shown, a dielectric capping layer 60 can be formed on multiple metal track structures RS, bonding pads BP, and etch stop layers 38. The dielectric capping layer 60 can be formed substantially conformally on each metal track structure RS, bonding pad BP, and etch stop layer 38 and directly contact each metal track structure RS, bonding pad BP, and etch stop layer 38. Therefore, the dielectric capping layer 60 can be partially formed in recesses RC1 and RC2 without completely filling recesses RC1 and RC2. Figure 7 and Figure 8 As shown, an opening OP can be formed, and the opening OP can penetrate the dielectric capping layer 60 and the second metal mask pattern 48B located on the bonding pad BP in the vertical direction D1. Then, a bonding copper wire WB can be formed on the bonding pad BP. The bonding copper wire WB can be at least partially disposed in the opening OP and directly connected to the second copper pattern 46B. The bonding copper wire WB can be connected to the second copper pattern 46B by wire bonding. By having the bonding copper wire WB of the same material in direct contact with the second metal mask pattern 48B, the contact resistance between the bonding copper wire WB and the bonding pad BP can be reduced, thereby improving the operation of the optical metasurface structure. Then, as... Figure 9 As shown, an encapsulation material 70 can be formed to cover the dielectric capping layer 60, the bonding pad BP, and the bonding copper wire WB above the second region R2, thereby providing protection for the bonding pad BP and the bonding copper wire WB. Figure 9 and Figure 1 As shown, after the encapsulation material 70 is formed, a liquid crystal material LC can be formed on the first region R1. The liquid crystal material LC can be at least partially located in each recess RC1, thereby forming a liquid crystal material LC as shown in the figure. Figure 1The optical metasurface structure 101 shown is illustrated. A dielectric capping layer 60 is formed on the metal track structure RS and the bonding pad BP before the liquid crystal material LC is formed, and a portion of the dielectric capping layer 60 can be sandwiched between the liquid crystal material LC and each metal track structure RS.

[0106] The following description will focus on different embodiments of the present invention. For the sake of simplicity, the description will mainly focus on the differences between the embodiments, and will not repeat the same points. In addition, the same elements in the various embodiments of the present invention are identified by the same reference numerals to facilitate comparison between the embodiments.

[0107] Please see Figure 10 and Figure 11 , Figure 10 The diagram shown is a schematic representation of the optical metasurface structure 102 according to a second embodiment of the present invention. Figure 11 The illustration shows a schematic diagram of the fabrication method of the optical metasurface structure in this embodiment. Figure 10 As shown, the optical metasurface structure 102 may further include a spacer SP and a cover plate 80. The spacer SP may be disposed above the second region R2 and located within the encapsulation material 70, while the cover plate 80 may be partially located above the first region R1 and partially located above the second region R2. The cover plate 80 may directly contact the liquid crystal material LC, the spacer SP, and the encapsulation material 70, while the spacer SP may be partially located in the recess RC2 to maintain the distance between the cover plate 80 and each metal track structure RS in the vertical direction D1. The spacer SP may be mainly disposed at the end points of the device and / or specific locations to provide a support effect, and in some embodiments, the height of the cover plate 80 may be controlled in other ways without the spacer SP, depending on design requirements. In some embodiments, the spacer SP may include an insulating engineering material, such as glass fiber microspheres, plastic microspheres, or silicone gaskets, but is not limited to these materials. The cover plate 80 may include a transparent substrate (e.g., but not limited to a glass substrate) and a transparent conductive layer (e.g., but not limited to a transparent indium tin oxide layer) disposed on the side of the transparent substrate facing the liquid crystal material LC. The transparent conductive layer may serve as a common electrode for controlling the state of the liquid crystal material LC, but is not limited thereto. In some embodiments, Figure 10 It can be regarded as a drawing Figure 11 A diagram illustrating the subsequent situation. (See example.) Figure 11 and Figure 10 As shown, in the manufacturing method of this embodiment, the liquid crystal material LC and the cover plate 80 can be formed after the encapsulation material 70 and the spacer SP are formed. The cover plate 80 may not cover the bonding copper wire WB in the vertical direction D1, but this is not a limitation. It is worth noting that the spacer SP and cover plate 80 of this embodiment can also be applied to other embodiments of the present invention as needed.

[0108] Please see Figures 12 to 14 . Figure 12 The diagram shown is a schematic representation of the optical metasurface structure 103 according to a third embodiment of the present invention. Figure 13 and Figure 14 The illustration shows a schematic diagram of the fabrication method of the optical metasurface structure in this embodiment, wherein... Figure 14 It is illustrated Figure 13 A schematic diagram of the subsequent situation. In some embodiments, Figure 12 It can be regarded as a drawing Figure 14 The following is a schematic diagram of the situation, but it is not limited to this. For example... Figure 12 As shown, in the optical metasurface structure 103, each metal track structure RS may not include the first metal mask pattern described in the first embodiment, and the bonding pad BP may not include the second metal mask pattern described in the first embodiment. Therefore, the dielectric capping layer 60 can directly contact the upper surface TS2 of the first copper pattern 46A in each metal track structure RS and the upper surface TS5 of the second copper pattern 46B in the bonding pad BP. The bottom surface of the bonding pad BP (e.g., bottom surface BS4) and the bottom surface of each metal track structure RS (e.g., bottom surface BS1) can be substantially coplanar, and the upper surface of the bonding pad BP (e.g., upper surface TS5) and the upper surface of each metal track structure RS (e.g., upper surface TS2) can be substantially coplanar. Please refer to... Figure 5 , Figure 13 , Figure 14 as well as Figure 12 In some implementations, Figure 13 It can be regarded as a drawing Figure 5 The following is a schematic diagram of the situation, but it is not limited to this. For example... Figure 5 and Figure 13 As shown, in some embodiments, the metal mask layer 48M can be removed by the patterning process 90. Therefore, each metal track structure RS and bonding pad BP formed by the patterning process 90 may not include the aforementioned first metal mask pattern and second metal mask pattern, respectively. The upper width (e.g., width W4) of the first copper pattern 46A can be considered as the upper width of the corresponding metal track structure RS, the upper surface TS2 of each first copper pattern 46A can be considered as the upper surface of the corresponding metal track structure RS, and the upper surface TS5 of the second copper pattern 46B can be considered as the upper surface of the bonding pad BP. Figure 14 and Figure 12 As shown, the dielectric capping layer 60 can be conformally formed on the sidewalls and top surfaces of each metal track structure RS and the sidewalls and top surfaces of the bonding pad BP, and the opening OP of this embodiment can penetrate the dielectric capping layer 60 located on the bonding pad BP in the vertical direction D1 to expose the second copper pattern 46B.

[0109] Please see Figure 15 . Figure 15The illustration shows a schematic diagram of the optical metasurface structure 104 according to a fourth embodiment of the present invention. Figure 15 As shown, in the optical metasurface structure 104, the opening OP can penetrate the dielectric capping layer 60 located on the bonding pad BP in the vertical direction D1 but does not penetrate the second metal mask pattern 48B in the bonding pad BP. The bonding copper wire WB can be disposed on the second metal mask pattern 48B in the vertical direction D1 and directly contact the upper surface of the second metal mask pattern 48B.

[0110] In summary, in the optical metasurface structure and its fabrication method of the present invention, a tunable optical metasurface structure can be realized by using a metal track structure with an upper width smaller than a lower width in combination with a liquid crystal material. Furthermore, the metal track structure and the bonding pad can be formed together using the same fabrication process, thereby simplifying the fabrication process and / or reducing production costs.

[0111] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention should be included within the scope of the present invention.

Claims

1. An optical metasurface structure, comprising: The base includes the first region and the second region; Multiple metal track structures are installed on this first zone; as well as A liquid crystal material is disposed on the first region, wherein at least a portion of the liquid crystal material is located horizontally between adjacent metal track structures, and the upper width of one of the metal track structures is smaller than the bottom width of the metal track structure.

2. The optical metasurface structure as claimed in claim 1, wherein each of the metal track structures comprises: First obstacle pattern; as well as A first copper pattern is disposed on the first barrier pattern, wherein the upper width of the first copper pattern is smaller than the bottom width of the first copper pattern.

3. The optical metasurface structure as described in claim 2, wherein each of the metal track structures further comprises: A first metal mask pattern is disposed on the first copper pattern, wherein the upper width of the first metal mask pattern is smaller than the bottom width of the first metal mask pattern.

4. The optical metasurface structure as described in claim 2, further comprising: A dielectric capping layer is disposed on the plurality of metal track structures, wherein a portion of the dielectric capping layer is sandwiched between the liquid crystal material and each of the metal track structures, and the dielectric capping layer is disposed on the sidewall of the first barrier pattern of each of the metal track structures and directly contacts the sidewall of the first barrier pattern of each of the metal track structures.

5. The optical metasurface structure as described in claim 1, further comprising: A bonding pad is disposed on the second region, wherein the material composition of the bonding pad is the same as that of each of the metal track structures.

6. The optical metasurface structure of claim 5, wherein the bottom surface of the bonding pad is coplanar with the bottom surface of each of the metal track structures, and the upper surface of the bonding pad is coplanar with the upper surface of each of the metal track structures.

7. The optical metasurface structure as described in claim 5, further comprising: A dielectric capping layer is disposed on the plurality of metal track structures and the bonding pad, wherein a portion of the dielectric capping layer is sandwiched between the liquid crystal material and each of the metal track structures.

8. The optical metasurface structure of claim 7, wherein the bonding pad comprises: Second obstacle pattern; as well as The second copper pattern is set on the second barrier pattern.

9. The optical metasurface structure of claim 8, wherein the bonding pad further comprises a second metal mask pattern disposed on the second copper pattern, and the optical metasurface structure further comprises: An opening extends through the dielectric capping layer located on the bonding pad and the second metal mask pattern; as well as The copper wire is partially disposed in the opening and directly connected to the second copper pattern.

10. The optical metasurface structure as described in claim 5, further comprising: A dielectric layer is disposed on the first region and the second region of the substrate; as well as A connection structure is disposed in the dielectric layer, wherein the bonding pad and the plurality of metal track structures are disposed on the dielectric layer and the connection structure, and the bonding pad is electrically connected to at least one of the plurality of metal track structures through the connection structure.

11. A method for fabricating an optical metasurface structure, comprising: A substrate is provided, the substrate comprising a first region and a second region; Multiple metal track structures were formed on top of this first zone; as well as A liquid crystal material is formed on the first region, wherein at least a portion of the liquid crystal material is located horizontally between adjacent metal track structures, and the upper width of one of the metal track structures is smaller than the bottom width of the metal track structure.

12. The method for fabricating the optical metasurface structure as described in claim 11, further comprising: A bonding pad is formed on the second region, wherein the material composition of the bonding pad is the same as that of each of the metal track structures, and the bonding pad and the plurality of metal track structures are formed together by the same manufacturing process.

13. The method for fabricating an optical metasurface structure as claimed in claim 12, wherein the method for forming the bonding pad and the plurality of metal track structures comprises: Barrier material layers are formed on the first region and the second region of the substrate; A copper layer is formed on the barrier material layer; as well as A patterning process is performed, wherein the barrier material layer is patterned by the patterning process to become a patterned barrier layer, and the copper layer is patterned by the patterning process to become a patterned copper layer. The patterned barrier layer includes multiple first barrier patterns located on the first region and a second barrier pattern located on the second region. The patterned copper layer includes multiple first copper patterns located on the first region and a second copper pattern located on the second region. Each metal track structure includes one of the multiple first barrier patterns and one of the multiple first copper patterns. The bonding pad includes the second barrier pattern and the second copper pattern.

14. The method for fabricating an optical metasurface structure as described in claim 13, wherein the patterning fabrication process includes an ion beam etching (IBE) fabrication process.

15. The method for fabricating an optical metasurface structure as described in claim 13, wherein the upper width of one of the plurality of first copper patterns is smaller than the bottom width of the first copper pattern.

16. The method for fabricating an optical metasurface structure as claimed in claim 13, wherein the method for forming the bonding pad and the plurality of metal track structures further comprises: Prior to the patterning process, a metal mask layer is formed on the copper layer, wherein the metal mask layer is patterned by the patterning process to become a patterned metal mask layer. The patterned metal mask layer includes a plurality of first metal mask patterns located on the first region and a second metal mask pattern located on the second region. Each metal track structure also includes one of the plurality of first metal mask patterns, and the bonding pad also includes the second metal mask pattern.

17. The method for fabricating an optical metasurface structure as described in claim 16, wherein the upper width of one of the plurality of first metal mask patterns is smaller than the bottom width of the first metal mask pattern.

18. The method for fabricating the optical metasurface structure as described in claim 16, further comprising: Before the liquid crystal material is formed, a dielectric capping layer is formed on the plurality of metal track structures and the bonding pad, wherein a portion of the dielectric capping layer is sandwiched between the liquid crystal material and each of the metal track structures.

19. The method for fabricating the optical metasurface structure as described in claim 18, further comprising: An opening is formed that extends through the dielectric capping layer located on the bonding pad and the second metal mask pattern; as well as A bonding copper wire is formed on the bonding pad, wherein a portion of the bonding copper wire is disposed in the opening and is directly connected to the second copper pattern.

20. The method for fabricating the optical metasurface structure as described in claim 12, further comprising: Before the bonding pad is formed with the plurality of metal track structures, a dielectric layer is formed on the first region and the second region of the substrate; as well as Before the bonding pad and the plurality of metal track structures are formed, a connection structure is formed in the dielectric layer, wherein the bonding pad and the plurality of metal track structures are formed on the dielectric layer and the connection structure, and the bonding pad is electrically connected to at least one of the plurality of metal track structures through the connection structure.

Images