Image device and forming method thereof

Abstract

The invention relates to an image device and a forming method thereof. The image device comprises a plurality of photodiodes, a color filter layer and a metasurface layer. The color filter layer is arranged above the photodiode. The color filter layer comprises a first green filter and a second green filter. The metasurface layer is over the color filter layer and includes pixel cells. The pixel unit includes a first green region over the first green filter and a second green region over the second green filter. The first green region includes a first central nanopillar. Viewed from an upper view, the first center nanopillar is displaced from the center of the first green region by a first longitudinal offset in the Y-axis direction of the first center nanopillar and by a first lateral offset in the X-axis direction of the first center nanopillar. The metasurface layer allows the incident light to have a large incident angle range, and provides equilibrium quantum efficiency for different green pixels in the Bayer array to avoid channel separation of different green pixels and improve performance of the image device.

Description

Technical Field

[0001] The present disclosure relates to an imaging device and a method for forming an imaging device. Background Art

[0002] In a complementary metal oxide semiconductor (CMOS) image sensor (also known as a CIS), receiving elements, such as microlens layers or metasurface layers, receive and separate incident light of varying wavelengths and colors. A color filter layer can be positioned beneath the receiving elements and act as an absorber, absorbing light of specific wavelengths before it is transmitted to the photodiode. The color routing of light within an imaging device further impacts its performance.

[0003] However, the pattern of color filters in the color filter layer and the design of the metasurface layer (for example, the arrangement and shape of the nanostructures in the metasurface layer) can affect the color routing of light. Therefore, it is necessary to design the metasurface layer to improve the performance of imaging devices. Summary of the Invention

[0004] One embodiment of the present disclosure provides an imaging device. The imaging device includes a plurality of photodiodes, a color filter layer, and a metasurface layer. The color filter layer is above the plurality of photodiodes, wherein the color filter layer includes a blue filter, a red filter, a first green filter, and a second green filter. The metasurface layer is above the color filter layer and includes a first pixel unit, wherein the first pixel unit includes a blue region above the blue filter, a red region above the red filter, a first green region above the first green filter, and a second green region above the second green filter. The first green region includes a first central nanopillar, wherein, from a top view, the first central nanopillar is displaced from the center of the first green region by a first longitudinal offset in the Y-axis direction of the first central nanopillar and by a first lateral offset in the X-axis direction of the first central nanopillar. The second green region includes a second central nanopillar, wherein, from a top view, the second central nanopillar is displaced from the center of the second green region by a second longitudinal offset in the Y-axis direction of the second central nanopillar and by a second lateral offset in the X-axis direction of the second central nanopillar.

[0005] In some embodiments, the first longitudinal offset and the first lateral offset are determined based on an incident angle and an azimuth angle of the first green region. The incident angle of the first green region is the angle between the first incident light on the upper surface of the first green region and the normal to the upper surface of the first green region. The azimuth angle of the first green region is the angle between a horizontal axis passing through the center of the metasurface layer and a first connecting line, where the first connecting line is located between the center of the first green region and the center of the metasurface layer.

[0006] In some embodiments, the metasurface layer further includes a second pixel unit, wherein the second pixel unit includes a third green area, and the third green area includes a third central nanocolumn. From the top view, the third central nanocolumn is displaced from the center of the third green area in the Y-axis direction of the third central nanocolumn by a third longitudinal offset, and in the X-axis direction of the third central nanocolumn by a third lateral offset, wherein the third longitudinal offset and the third lateral offset are determined according to the incident angle and azimuth angle of the third green area. The incident angle of the third green area is the angle between the second incident light on the upper surface of the third green area and the normal to the upper surface of the third green area. The azimuth angle of the third green area is the angle between the horizontal axis passing through the center of the metasurface layer and the second connecting line, wherein the second connecting line is located between the center of the third green area and the center of the metasurface layer. The first longitudinal offset of the first central nanocolumn and the third longitudinal offset of the third central nanocolumn satisfy the following equations:

[0007]

[0008] Where θ is the incident angle of the first green area, and θ is not equal to 0 degrees, is the azimuth of the first green area, is the first longitudinal offset of the first central nanorod, θ i is the incident angle of the third green region, and θ i Not equal to 0 degrees, The azimuth of the third green area, is the third longitudinal offset of the third central nanorod, Δθ is the first difference between the incident angle of the first green region and the incident angle of the third green region, and is a second difference between the azimuth angle of the first green area and the azimuth angle of the third green area.

[0009] In some embodiments, the first lateral offset of the first central nanopillar and the third lateral offset of the third central nanopillar satisfy the following equation:

[0010]

[0011] in is the first lateral offset of the first central nanopillar, and is the third lateral offset of the third central nanocolumn.

[0012] In some embodiments, an edge of the first green region is displaced from a corresponding edge of the first green filter by an offset distance of the first green region, the color filter layer includes a third green filter adjacent to the first green filter, the third green region is above the third green filter, and an edge of the third green region is displaced from a corresponding edge of the third green filter by an offset distance of the third green region. The offset distance of the first green region and the offset distance of the third green region satisfy the following equation:

[0013]

[0014] Where S(θ) is the offset distance of the first green area, and S(θ i ) is the offset distance of the third green area.

[0015] In some embodiments, the offset distance of the first green region is in the range of 0 nm to 300 nm, θ is greater than 0 degrees and ≤ 35 degrees, In the range of 0 degrees to 360 degrees.

[0016] In some embodiments, the metasurface layer further includes a plurality of peripheral nanopillars, and the plurality of peripheral nanopillars are located at a plurality of corners of the blue region, the red region, the first green region, and the second green region.

[0017] In some embodiments, the first longitudinal offset of the first central nanorod is within 1 / 5 of the size of the first green filter, and the first lateral offset of the first central nanorod is within 1 / 5 of the size of the first green filter.

[0018] In some embodiments, the first longitudinal offset and the first lateral offset comprise a positive offset, and the second longitudinal offset and the second lateral offset comprise a positive offset. A positive offset of the first longitudinal offset is defined as an offset from the first green region toward the red region, and a positive offset of the first lateral offset is defined as an offset from the first green region toward the blue region. A positive offset of the second longitudinal offset is defined as an offset from the second green region toward the blue region, and a positive offset of the second lateral offset is defined as an offset from the second green region toward the red region.

[0019] In some embodiments, the first longitudinal offset and the first lateral offset comprise a negative offset, and the second longitudinal offset and the second lateral offset comprise a negative offset. A negative offset of the first longitudinal offset is defined as an offset from the first green region away from the red region, and a negative offset of the first lateral offset is defined as an offset from the first green region away from the blue region. A negative offset of the second longitudinal offset is defined as an offset from the second green region away from the blue region, and a negative offset of the second lateral offset is defined as an offset from the second green region away from the red region.

[0020] In some embodiments, the metasurface layer further comprises a filling material, the filling material laterally surrounding the first central nanorod and the second central nanorod, wherein a refractive index of the filling material is in a range of 1.0 to 1.6.

[0021] In some embodiments, the imaging device further includes a dielectric layer, wherein the dielectric layer is disposed between the color filter layer and the blue filter, the red filter, the first green filter, and the second green filter.

[0022] In some embodiments, a size of each of the blue region, the red region, the first green region, and the second green region is in a range of 400 nm to 700 nm, and a refractive index of the first central nanorod is in a range of 1.8 to 3.5.

[0023] One embodiment of the present disclosure provides a method for forming an imaging device. The method comprises the following steps. A plurality of photodiodes are provided. A color filter layer is formed above the plurality of photodiodes, wherein the color filter layer comprises a blue filter, a red filter, a first green filter, and a second green filter. A metasurface layer is formed above the color filter layer, wherein the metasurface layer comprises a first pixel unit, the first pixel unit comprises a blue region above the blue filter, a red region above the red filter, a first green region above the first green filter, and a second green region above the second green filter, wherein the first green region comprises a first central nanocolumn, and the second green region comprises a second central nanocolumn. Forming a metasurface layer includes the following steps: forming a first central nanopillar, wherein the first central nanopillar is displaced from the center of the first green region in the Y-axis direction of the first central nanopillar by a first longitudinal offset and in the X-axis direction of the first central nanopillar as viewed from above; and forming a second central nanopillar, wherein the second central nanopillar is displaced from the center of the second green region in the Y-axis direction of the second central nanopillar by a second longitudinal offset and in the X-axis direction of the second central nanopillar as viewed from above.

[0024] In some embodiments, the first longitudinal offset and the first lateral offset are determined based on an incident angle and an azimuth angle of the first green region. The incident angle of the first green region is the angle between the first incident light on the upper surface of the first green region and the normal to the upper surface of the first green region. The azimuth angle of the first green region is the angle between a horizontal axis passing through the center of the metasurface layer and a first connecting line, where the first connecting line is located between the center of the first green region and the center of the metasurface layer.

[0025] In some embodiments, forming the metasurface layer further includes forming a plurality of peripheral nanorods at corners of the blue region, the red region, the first green region, and the second green region.

[0026] In some embodiments, forming the Metasurface layer further includes forming a filling material, wherein the filling material laterally surrounds the plurality of peripheral nano-pillars, the first central nano-pillar, and the second central nano-pillar.

[0027] In some embodiments, the method further includes forming a dielectric layer, wherein the dielectric layer is disposed between the color filter layer and the blue filter, the red filter, the first green filter, and the second green filter.

[0028] In some embodiments, the first longitudinal offset and the first lateral offset comprise a positive offset, and the second longitudinal offset and the second lateral offset comprise a positive offset. A positive offset of the first longitudinal offset is defined as an offset from the first green region toward the red region, and a positive offset of the first lateral offset is defined as an offset from the first green region toward the blue region. A positive offset of the second longitudinal offset is defined as an offset from the second green region toward the blue region, and a positive offset of the second lateral offset is defined as an offset from the second green region toward the red region.

[0029] In some embodiments, the first longitudinal offset and the first lateral offset comprise a negative offset, and the second longitudinal offset and the second lateral offset comprise a negative offset. A negative offset of the first longitudinal offset is defined as an offset from the first green region away from the red region, and a negative offset of the first lateral offset is defined as an offset from the first green region away from the blue region. A negative offset of the second longitudinal offset is defined as an offset from the second green region away from the blue region, and a negative offset of the second lateral offset is defined as an offset from the second green region away from the red region. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] This disclosure will be fully understood when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard industry practice, the features are not drawn to scale and are for illustrative purposes only. In fact, the dimensions of the features may be arbitrarily increased or decreased for clarity of discussion.

[0031] Figure 1FIG. 4 is a perspective view of an imaging device according to some embodiments of the present disclosure when incident light is not incident in a vertical direction.

[0032] Figure 2 For part Figure 1 A side view of the imaging device in FIG.

[0033] Figure 3 for Figure 1 Top view of the metasurface layer in the image.

[0034] Figure 4A FIG. 4 is a top view of a configuration of a metasurface layer according to some embodiments of the present disclosure when incident light is incident in a vertical direction.

[0035] Figure 4B for Figure 1 Top view of the configuration of the metasurface layer.

[0036] Figure 5A is a coordinate diagram when the incident light is incident in a vertical direction, which is used to illustrate the definitions of different parameters.

[0037] Figures 5B to 5D is a coordinate diagram when the incident light is not incident in a vertical direction, which is used to illustrate the definitions of different parameters.

[0038] Figure 5E Schematic diagram of an array of metasurface layers according to some embodiments of the present disclosure.

[0039] Figure 5F Schematic diagram of the reference point.

[0040] Figure 6A The third green area according to some embodiments of the present disclosure is shown at an incident angle (θ i ) is a side view of part of the imaging device.

[0041] Figure 6B FIG. 1 is a side view of a portion of an imaging device showing a first green region at an incident angle (θ) according to some embodiments of the present disclosure.

[0042] Figure 7 FIG. 4 is a top view of a metasurface layer according to some embodiments of the present disclosure.

[0043] The description of the accompanying drawings is as follows:

[0044] 100,100a,100b: Video Installation

[0045] 110: Photoelectric conversion layer

[0046] 112: Base material

[0047] 114: Deep Trench Isolation (DTI)

[0048] 116: Photodiode

[0049] 120: Anti-reflective layer

[0050] 130: Color filter layer

[0051] 131: Top

[0052] 132: Grille structure

[0053] 135: Shading structure

[0054] 140: Dielectric layer

[0055] 150,750: Metasurface layer

[0056] 151a, 151b: Configuration

[0057] 152: Filling material

[0058] 154: Nanostructure

[0059] 154A: Peripheral nanopillars

[0060] 154B: Central nanopillar

[0061] OBxi,OByi,OG1xi,OG1yi,OG2xi,OG2yi,ORxi,ORyi: offset

[0062] BR_C,GR1_C,GR2_C,RR_C: center point

[0063] BR_P1,GR1_P1,GR1_P2,GR2_P1,GR2_P2,RR_P1: offset position

[0064] BR_dx1,GR1_dx1,GR1_dx2,GR2_dx1,GR2_dx2,RR_dx1: lateral offset

[0065] BR_dy1,GR1_dy1,GR1_dy2,GR2_dy1,GR2_dy2,RR_dy1: longitudinal offset

[0066] S(θ),S(θ i ): offset distance

[0067] CL1: First connecting line

[0068] CL2: Second connecting line

[0069] L: incident light

[0070] B: Blue filter

[0071] G1: First green filter

[0072] G2: Second green filter

[0073] G3: Third green filter

[0074] R: Red filter

[0075] BR: Blue Zone

[0076] GR1, GR2, GR3: Green Zone

[0077] RR: Red Zone

[0078] P1, P2: pixels

[0079] P1_a, P2_a: left pixel

[0080] P1_b, P2_b: right pixel

[0081] X, Y, Z: direction

[0082] θ,θ',θ i : Angle of incidence

[0083] Azimuth

[0084] C: Center DETAILED DESCRIPTION

[0085] The following disclosure provides many different embodiments or examples for implementing various features of the present disclosure. Specific embodiments of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, in the subsequent description, references to a first feature being formed above or on a second feature may include embodiments in which the first and second features are formed in direct contact, or may include embodiments in which another feature may be formed between the first and second features so that the first and second features are not in direct contact.

[0086] In addition, the present disclosure may repeat reference numerals and / or text in different examples. The purpose of repetition is to simplify and clarify the description, rather than to define the relationship between the different embodiments and / or configurations discussed.

[0087] It will be understood that although terms such as "first," "second," and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are merely used to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0088] In addition, spatially relative terms such as "below," "beneath," "below," "above," and similar terms are used herein for convenience in describing the relationship of one element or feature to another element or feature in the figures. Spatially relative terms encompass not only the orientation depicted in the figures but also other orientations of the device in use or operation. The device may be oriented in other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0089] In this disclosure, the terms "approximately," "about," and "substantially" generally mean within ±20%, or within ±10%, or within ±5%, or within ±3%, or within ±2%, or within ±1%, or even within ±0.5% of a given value or range. The quantities given in this disclosure are approximate values.

[0090] To accommodate shrinking pixel sizes, the amount of light received by each pixel (which can be defined by different color filters) and the uniformity of light reception across different pixels have become critical issues. Unbalanced (or uneven) light reception across different pixels can cause color variations in the imaging device and lead to insufficient quantum efficiency (QE) across different pixels, thus reducing the device's performance. Furthermore, the angle of incidence of the incident light also affects the QE of the imaging device.

[0091] The following drawings illustrate various embodiments of the present disclosure. For clarity, many practical details will be included in the following description. However, it should be understood that these practical details are not intended to limit the present disclosure. In other words, these practical details are not essential for some embodiments of the present disclosure. Furthermore, to simplify the drawings, some conventional structures and components are shown in simplified schematic form.

[0092] Because incident light is composed of different wavelengths of different colors, and the photodiodes in the imaging device are used to detect the incident light, the incident light needs to be separated by a metasurface layer and a color filter layer before it is transmitted to the photodiode. The metasurface is composed of multiple nanostructures (for example, nanoposts or pillars) that form a specific phase distribution. The metasurface provides the phase distribution required for different wavelengths. The metasurface guides different incident wavelengths to their respective target locations. This technology is called color routing. The "target locations" referred to here represent the different color filters in the color filter layer.

[0093] For example, after adjusting the phase distribution of the incident wavelength, the specific phase distribution is transmitted to the red filter that allows red light to pass through. The red light is then transmitted to the photodiode below the red filter, where the electrical signal of the red light is detected. In this case, the specific phase distribution of the red filter can be understood as being for red light.

[0094] The imaging device of the present disclosure takes into account that incident light of different incident angles in a CMOS array affects the quantum efficiency of different green pixels in a Bayer pattern. The position of the nanopillars in the metasurface layer of the present disclosure can be adjusted by the disclosed equation, which is calculated based on the incident angle and azimuth angle of the incident light of the nanopillars. The disclosed metasurface layer can provide similar amounts of quantum efficiency between different green pixels in a Bayer array, thereby avoiding channel separation of different green pixels and improving the performance of the imaging device. The "channel separation" referred to here represents the unbalanced quantum efficiency of the photodiodes in different green pixels.

[0095] Figure 1 1 is a perspective view of the imaging device 100 according to some embodiments of the present disclosure when the incident light is not incident in a vertical direction. In other words, Figure 1 The incident light L in the image is inclined relative to the upper surface of the metasurface layer 150 . Figure 2 For part Figure 1 100 is a side view of the imaging device 100. In detail, Figure 2 Only shown Figure 1 The image device 100 is a half portion (ie, the blue region BR, the first green region GR1 and the components thereunder). Figure 3 for Figure 1 Top view of the metasurface layer in the image.

[0096] exist Figure 1 and Figure 2In FIG. 1 , the imaging device 100 includes a photoelectric conversion layer 110 . The photoelectric conversion layer 110 includes a substrate 112 , a plurality of deep trench isolations (DTIs) 114 , and a plurality of photodiodes 116 .

[0097] like Figure 2 As shown, a plurality of DTIs 114 and a plurality of photodiodes 116 are embedded in a substrate 112, with each photodiode 116 disposed between every two DTIs 114. In some embodiments, the substrate 112 may be a single structure shared by all DTIs 114 and photodiodes 116 of the imaging device 100. The plurality of DTIs 114 are configured to avoid light interference between adjacent photodiodes 116. The photodiodes 116 are configured to sense incident light L and generate intensity signals that form image signals based on the intensity of the incident light L propagating therethrough.

[0098] In some embodiments, substrate 112 may be a semiconductor substrate, an organic photoelectric conversion layer, a semiconductor-on-insulator (SOI) substrate, or other suitable substrate. In other embodiments, devices such as transistors or photodiodes may be formed in an active region of substrate 112, where the active region is defined by DTI 114. In some embodiments, additional isolation structures may be used as alternative structures, such as shallow trench isolation (STI) structures and local oxidation of silicon (LOCOS) structures. In some embodiments, multiple DTIs 114 may be formed using a photolithography process.

[0099] exist Figure 1 and Figure 2 In the embodiment, the imaging device 100 includes an anti-reflection layer 120 disposed on a substrate 112. The anti-reflection layer 120 is configured to reduce reflection of light transmitted to the underlying photodiode 116. In some embodiments, the anti-reflection layer 120 may be made of silicon oxynitride (SiO x N y , where x and y are both in the range of 0 to 1).

[0100] Figure 1 and Figure 2In the embodiment, the imaging device 100 includes a color filter layer 130 disposed on the anti-reflection layer 120. The color filter layer 130 includes a plurality of color filters, for example, a blue filter B, a first green filter G1, a second green filter G2, and a red filter R. As can be seen from the top view, the color filter layer 130 is arranged in a 2×2 array. In some embodiments, the color filter layer 130 is arranged according to a Bayer array. Figure 2 As shown, the color filter layer 130 further includes a plurality of grid structures 132 and a plurality of light shielding structures 135. The grid structure 132 is adjacent to the color filter. Figure 2 As shown, the grid structure 132 is adjacent to the blue filter B and the first green filter G1. The grid structure 132 is configured to isolate light within a specific cell to achieve a light-trapping effect. Each light shielding structure 135 is embedded within each grid structure 132. The light shielding structure 135 is configured to prevent the underlying photodiode 116 from receiving additional light from a different color in an adjacent cell.

[0101] In some embodiments, each filter of the color filter layer 130 (e.g., the blue filter B, the first green filter G1, the second green filter G2, and the red filter R) allows light within a predetermined range of wavelengths to pass therethrough. For example, the red filter R allows light wavelengths in the range of 620 nm to 750 nm (red light) to pass through the corresponding photodiode 116, the first green filter G1 and the second green filter G2 allow light wavelengths in the range of 495 nm to 570 nm (green light) to pass through the corresponding photodiode 116, and the blue filter B allows light wavelengths in the range of 450 nm to 495 nm (blue light) to pass through the corresponding photodiode 116. The first green filter G1 can be identical to the second green filter G2.

[0102] In some embodiments, the height of the color filter layer 130 is in a range of approximately 0.3 μm to approximately 2.0 μm, for example, 0.5, 0.9, 1.2, 1.5, or 1.8 μm. In some embodiments, depending on the design requirements of the imaging device 100, the height of the grid structure 132 may be greater than or equal to the height of the light shielding structure 135. In some embodiments, the height of the light shielding structure 135 is in a range of approximately 0.005 μm to approximately 2 μm. In some embodiments, the grid structure 132 may be formed of a material including a transparent dielectric material. In some embodiments, the light shielding structure 135 may be formed of a material including an opaque metal, for example, tungsten (W), aluminum (Al), an opaque metal nitride, an opaque metal oxide, other suitable materials, or combinations thereof.

[0103] In the present disclosure, a "pixel" is defined by a color filter, and each pixel may correspond to at least one photodiode. Figure 2 In FIG, pixel P1 is defined by the blue filter B of the color filter layer 130, and pixel P1 corresponds to two photodiodes 116. The photodiodes 116 below the blue filter B are arranged in a 2×2 array, for example, a dual photodiode (DPD). When the photodiodes 116 are arranged in a 2×2 array, the blue filter B corresponds to four photodiodes 116. Figure 2 As shown, the pixel P1 includes a left pixel P1_a and a right pixel P1_b, wherein the left pixel P1_a and the right pixel P1_b respectively correspond to a photodiode 116 .

[0104] Similarly, in Figure 2 In FIG, the pixel P2 is defined by the first green filter G1 of the color filter layer 130, and the pixel P2 corresponds to two photodiodes 116. The photodiodes 116 below the first green filter G1 are arranged in a 2×2 array. Figure 2 As shown, pixel P2 includes a left pixel P2_a and a right pixel P2_b, wherein the left pixel P2_a and the right pixel P2_b respectively correspond to a photodiode 116. It is understood that each DTI 114 can be regarded as the boundary of the left pixel P1_a, the right pixel P1_b, the left pixel P2_a or the right pixel P2_b. Each grid structure 132 can be regarded as the boundary of different pixels (for example, pixel P1 or pixel P2). The center line (not shown) of the grid structure 132 can define the boundary of different pixels. In other words, Figure 2 The middle grid structure 132 spans the boundary between pixel P1 and pixel P2. In some embodiments, the size of pixel P1 and pixel P2 is respectively in the range of about 400 nm to about 700 nm, for example, 500 or 600 nm.

[0105] It should be understood that in each pixel (e.g., pixel P1 or pixel P2), the photodiodes 116 may be arranged in an m×n array, where m and n are positive integers and may be the same or different, but are not limited thereto. For example, the photodiodes 116 below the blue filter B may be arranged in a 1×2 array, such as a DPD, and the photodiodes 116 below the first green filter G1 may be arranged in a 1×2 array. When the photodiodes 116 are arranged in a 1×2 array, the blue filter B corresponds to two photodiodes 116, and the first green filter G1 also corresponds to two photodiodes 116.

[0106] Figure 1 and Figure 2In the embodiment, the imaging device 100 includes a dielectric layer 140 (also referred to as a spacer layer) disposed on the color filter layer 130. Figure 2 As shown, dielectric layer 140 covers the top 131 of color filter layer 130 (e.g., blue filter B and first green filter G1) and grid structure 132. In embodiments of imaging device 100, dielectric layer 140 can provide paths for differently diffracted incident light L to travel to their respective targets (different color filters in color filter layer 130). In some embodiments, the top 131 of the color filter in color filter layer 130 is trapezoidal, with its upper surface smaller than its lower surface.

[0107] In some embodiments, the thickness of dielectric layer 140 is in a range from about 0.1 μm to about 0.5 μm, for example, 0.2, 0.3, or 0.4 μm. The dimensions of dielectric layer 140 can be adjusted based on the design requirements of imaging device 100. In some embodiments, dielectric layer 140 can be formed of silicon oxide, silicon nitride, silicon carbide, silicon carbonitride (SiCN), silicon oxynitride, silicon oxycarbonitride, tetraethyl orthosilicate (TEOS), a low-k dielectric material, or other suitable materials.

[0108] Figure 1 and Figure 2 In the embodiment, the imaging device 100 includes a metasurface layer 150 disposed on a dielectric layer 140. In other words, the metasurface layer 150 is disposed above the color filter layer 130. Figures 1 to 3 As shown, the metasurface layer 150 has a blue region BR, a first green region GR1, a second green region GR2, and a red region RR, arranged in a 2×2 array. Specifically, the blue region BR is above the blue filter B, the first green region GR1 is above the first green filter G1, the second green region GR2 is above the second green filter G2, and the red region RR is above the red filter R. In some embodiments, each dimension of the blue region BR, the first green region GR1, the second green region GR2, and the red region RR is in the range of approximately 400 nm to approximately 700 nm. In some embodiments, the height of the metasurface layer is in the range of approximately 0.7 μm to approximately 1.5 μm, for example, 1.2 μm.

[0109] exist Figures 1 to 3In the metasurface, the metasurface layer 150 includes a filler material 152 and a plurality of nanostructures 154. The filler material 152 laterally encloses the nanostructures 154. The nanostructures 154 include a plurality of peripheral nanopillars 154A and a plurality of central nanopillars 154B. Specifically, the peripheral nanopillars 154A are located at the corners of each of the blue region BR, the first green region GR1, the second green region GR2, and the red region RR. Within each of the blue region BR, the first green region GR1, the second green region GR2, and the red region RR, a central nanopillar 154B is surrounded by a plurality of peripheral nanopillars 154A.

[0110] like Figure 2 As shown, Figure 2 The central peripheral nanopillar 154A spans the boundary between the blue region BR and the first green region GR1, and each central nanopillar 154B is not shared with the adjacent color region. Each peripheral nanopillar 154A is aligned with each grid structure 132. For example, the center line of the peripheral nanopillar 154A is aligned with the center line of the grid structure 132. To more clearly illustrate the configuration of the nanostructure 154, Figure 1 The dielectric filler material 152 is shown in dashed lines.

[0111] In an embodiment of the imaging device 100, the nanostructures 154 are cylindrical. In some embodiments, the central nanopillar 154B and the peripheral nanopillars 154A have circular, rectangular, or triangular outlines when viewed from above. In alternative embodiments, a plurality of intermediate nanopillars (not shown) may be disposed between the central nanopillar 154B and the peripheral nanopillars 154A within each of the blue region BR, the first green region GR1, the second green region GR2, and the red region RR. In some embodiments, the intermediate nanopillars are arranged in a circular pattern, with the central nanopillar 154B located at the center of the circular arrangement.

[0112] Please refer to Figure 2 and Figure 3. The central nanopillar 154B within the blue region BR has offsets OBxi and OByi relative to the center point BR_C of the blue region BR. The central nanopillar 154B within the first green region GR1 has offsets OG1xi and OG1yi relative to the center point GR1_C of the first green region GR1. The central nanopillar 154B within the second green region GR2 has offsets OG2xi and OG2yi relative to the center point GR2_C of the second green region GR2. The central nanopillar 154B within the red region RR has offsets ORxi and ORyi relative to the center point RR_C of the red region RR. The offsets OBxi, OG1xi, OG2xi, and ORxi represent the offsets along the direction X when the incident angle of the incident light L is tilted relative to the upper surface of the metasurface layer 150. The offsets OByi, OG1yi, OG2yi, and ORyi represent the offsets along the direction Y when the incident angle of the incident light L is tilted relative to the upper surface of the metasurface layer 150. In some embodiments, the offsets OBxi, OG1xi, OG2xi, and ORxi and the offsets OByi, OG1yi, OG2yi, and ORyi may be pixel P1 (refer to Figure 2 ) is within 1 / 5 of the size. The layout of the nanostructure 154 will be as follows Figure 4B discussed in .

[0113] Figure 4A 1 is a top view of a configuration 151 a of a metasurface layer according to some embodiments of the present disclosure when incident light L is incident in a vertical direction. Figure 5A The coordinate diagram is for the case where the incident light is incident in a vertical direction, which is used to illustrate the definition of different parameters. The "vertical incident direction" referred to here means that the incident angle of the incident light L is parallel to the direction Z.

[0114] exist Figure 5A In the three-dimensional coordinates, θ is the incident angle of the incident light L. It can be understood that when the incident angle of the incident light L is perpendicular to the XY plane, the incident angle θ is equal to 0 degrees, and Figure 4A The configuration 151a shown is a case where the incident light L is incident in a vertical direction. In other words, when the incident angle θ is equal to 0, the normal vector of the XY plane is parallel to the incident angle of the incident light L.

[0115] Figure 4B for Figure 1 FIG. 1 is a top view of the configuration 151 b of the metasurface layer 150 . Figures 5B to 5D is a coordinate diagram when the incident light is not incident in a vertical direction, which is used to illustrate the definition of different parameters. It should be understood that Figure 4A and Figure 4B The difference in conditions is that the incident angle of the incident light L makes the configurations 151a and 151b different. In detail, Figure 4A The metasurface layer in the figure is the case where the incident light L is normal incidence, and Figure 4B The metasurface layer in is the case where the incident light L is not normal incident (ie, oblique incident).

[0116] and Figure 4A Compared to the offset in the configuration 151a, when the incident light L is not incident in a vertical direction (i.e., the incident angle of the incident light L is inclined relative to the upper surface of the metasurface layer 150), the offset of the central nanorods 154B in the first green region GR1 and the second green region GR2 has an additional offset. Figure 4A and Figure 4B , Figure 4A and Figure 4B The difference in the configuration lies in the position of the central nanorod 154B in the first green region GR1 and the central nanorod 154B in the second green region GR2.

[0117] Please refer to Figure 4A In the blue region BR, the central nanopillar 154B is offset from the center point BR_C by an offset distance to an offset position BR_P1, where the offset distance is defined by a lateral offset BR_dx1 in the X-axis direction and a longitudinal offset BR_dy1 in the Y-axis direction. In the first green region GR1, the central nanopillar 154B is offset from the center point GR1_C by an offset distance to an offset position GR1_P1, where the offset distance is defined by a lateral offset GR1_dx1 in the X-axis direction and a longitudinal offset GR1_dy1 in the Y-axis direction. In the second green region GR2, the central nanopillar 154B is offset from the center point GR2_C by an offset distance to an offset position GR2_P1, where the offset distance is defined by a lateral offset GR2_dx1 in the X-axis direction and a longitudinal offset GR2_dy1 in the Y-axis direction. In the red region RR, the central nanorod 154B is displaced from the center point RR_C by an offset distance to an offset position RR_P1, wherein the offset distance is defined by a lateral offset RR_dx1 in the X-axis direction and a longitudinal offset RR_dy1 in the Y-axis direction. It is understood that the "lateral offset" referred to herein refers to an offset in a direction parallel to the X-axis, and the "longitudinal offset" refers to an offset in a direction parallel to the Y-axis. In some embodiments, the lateral offset and longitudinal offset can be at pixel P1 (reference Figure 2 ) within 1 / 5 of the size.

[0118] Please refer to Figure 4BIn the first green region GR1, the central nanopillar 154B is displaced from the offset position GR1_P1 to the offset position GR1_P2 by an additional offset distance, where the additional offset distance is defined by the lateral offset GR1_dx2 in the X-axis direction and the longitudinal offset GR1_dy2 in the Y-axis direction. In the second green region GR2, the central nanopillar 154B is displaced from the offset position GR2_P1 to the offset position GR2_P2 by an additional offset distance, where the additional offset distance is defined by the lateral offset GR2_dx2 in the X-axis direction and the longitudinal offset GR2_dy2 in the Y-axis direction.

[0119] It should be understood that Figure 4B The lateral offset BR_dx1 and longitudinal offset BR_dy1 in are equal to Figure 3 The offsets OBxi and OByi in . Figure 4B The lateral offset GR1_dx1 plus the lateral offset GR1_dx2 equals Figure 3 The offset in OG1xi. Figure 4B The longitudinal offset GR1_dy1 plus the longitudinal offset GR1_dy2 equals Figure 3 The offset in OG1yi. Figure 4B The lateral offset GR2_dx1 plus the lateral offset GR2_dx2 equals Figure 3 The offset in OG2xi. Figure 4B The longitudinal offset GR2_dy1 plus the longitudinal offset GR2_dy2 equals Figure 3 The offset in OG2yi. Figure 4B The lateral offset RR_dx1 and longitudinal offset RR_dy1 in are equal to Figure 3 The offsets ORxi and ORyi in .

[0120] exist Figure 4B In the embodiment, the lateral offset GR1_dx2 in the first green region GR1 is equal to the lateral offset GR2_dx2 in the second green region GR2, and the longitudinal offset GR1_dy2 in the first green region GR1 is equal to the longitudinal offset GR2_dy2 in the second green region GR2.

[0121] Please refer to Figures 5B to 5D θ is the incident angle of the incident light L, and is the azimuth angle. Figure 3 ) when the top surface is tilted, the incident angle θ of the incident light L is no longer 0 degrees. Therefore, the incident angle θ is defined as the angle between the incident direction of the incident light L and the normal vector of the XY plane coordinate. The azimuth angle corresponds to the angle on the XY plane coordinate.

[0122] Please refer to the following equation, D GR and D GB are the angle of incidence θ and the azimuth The incident angle θ and the azimuth angle For reference Figures 5B to 5D .

[0123] like Figure 5B and Figure 5C As shown, the location and location With the same incident angle but different azimuth angles, where θ is no greater than 35 degrees, In the range of 0 to 360 degrees, and like Figure 5B and Figure 5D As shown, the location and location With the same azimuth, but different angles of incidence, where θ is no greater than 35 degrees, In the range of 0 to 360 degrees, θ′>θ. All cases where the incident light L is not incident in a vertical direction can be calculated by the following equation. and It changes according to the incident angle and azimuth of the incident light L.

[0124] Figure 5E Schematic diagram of an array of a metasurface layer 150 according to some embodiments of the present disclosure. Here, a "pixel unit" is composed of a blue region BR, a first green region GR1, a second green region GR2, and a red region RR. The metasurface layer 150 is composed of a plurality of pixel units, such as Figure 5E shown. Figure 5E The first pixel unit and the second pixel unit adjacent to the first pixel unit are shown. It can be understood that the blue region BR, the first green region GR1, the second green region GR2 and the red region RR in the first pixel unit and the second pixel unit each include a central nanocolumn 154B.

[0125] refer to Figure 4B and Figure 5E , according to the incident angle θ and azimuth angle in the first green region GR1 Determine the lateral offset GR1_dx1 and the lateral offset GR1_dx2 in the first green region GR1. The longitudinal offset GR1_dy1 and the longitudinal offset GR1_dy2 in the first green region GR1 are determined. The incident angle θ of the first green region GR1 is the first incident light L on the upper surface of the first green region GR1 (reference Figure 1 and Figure 5B ) and the normal to the upper surface of the first green region GR1. Figure 5E , the azimuth of the first green region GR1 is the included angle between the horizontal axis X passing through the center C of the Metasurface layer 150 and the first connection line CL1 , wherein the first connection line CL1 is located between the center of the first green region GR1 and the center C of the Metasurface layer 150 .

[0126] like Figure 5E As shown, the metasurface layer 150 further includes a second pixel unit, wherein the second pixel unit includes a third green region, the third green region includes a third central nanocolumn, and the third central nanocolumn is displaced from the center of the third green region by a third longitudinal offset and a third lateral offset, wherein according to the incident angle θ of the third green region i and azimuth To determine the third longitudinal offset and the third lateral offset. The incident angle θ of the third green area i is the angle between the second incident light on the upper surface of the third green region and the normal to the upper surface of the third green region. is the angle between the horizontal axis X passing through the center C of the Metasurface layer 150 and the second connection line CL2, wherein the second connection line CL2 is located between the center of the third green region and the center C of the Metasurface layer 150. The longitudinal offset GR1_dy1 and the longitudinal offset GR1_dy2 of the central nanorod 154B in the first green region GR1 (refer to Figure 4B ) and the third longitudinal offset of the third central nanopillar satisfy the following equation:

[0127]

[0128] Where θ is the incident angle of the first green area, and θ is not equal to 0 degrees, is the azimuth of the first green area, The longitudinal offset GR1_dy1 of the first central nanorod plus the longitudinal offset GR1_dy2, θ i is the incident angle of the third green region, and θ i Not equal to 0 degrees, is the azimuth of the third green area, is the third longitudinal offset of the third central nanorod, Δθ is the first difference between the incident angles of the first green region and the third green region, is a second difference between the azimuth angle of the first green area and the azimuth angle of the third green area.

[0129] Figure 5F Reference point 1 and reference point 2 represent the known Reference point 3 represents the unknown Reference point 3 may be obtained through the nearest reference point (eg, reference point 1 or reference point 2).

[0130] The lateral offset GR1_dx1 and the lateral offset GR1_dx2 (refer to Figure 4B ) and the third lateral offset of the third central nanopillar satisfy the following equation:

[0131]

[0132] in The lateral offset GR1_dx1 of the first central nanorod is added to the lateral offset GR1_dx2, is the third lateral offset of the third central nanocolumn.

[0133] In some embodiments, θ is greater than 0 degrees and ≤ 35 degrees, In the range of 0 degrees to 360 degrees.

[0134] get Figure 4B After the configuration 151b is formed, the nanostructure 154 (including the peripheral nanocolumns 154A and the central nanocolumns 154B) is formed according to the configuration 151b. Figure 3 As shown. In some embodiments, nanostructure 154 can be formed by a suitable deposition and patterning process, followed by forming filler material 152 to laterally surround peripheral nanopillars 154A and central nanopillar 154B. In alternative embodiments, peripheral nanopillars 154A and central nanopillar 154B are formed by depositing filler material 152, followed by etching a plurality of holes within filler material 152. In other words, nanostructure 154 can be a plurality of holes filled with ambient air, with the material of nanostructure 154 formed within the plurality of holes.

[0135] Please refer to Figures 1 to 3 In some embodiments, the size (e.g., diameter) of the nanostructure 154 in the top view is in the range of about 120 nm to about 250 nm. The size of the central nanopillar 154B can be equal to or larger than the size of the peripheral nanopillars 154A. Although the nanostructure 154 is shown as a circular shape in the top view, the present disclosure is not limited thereto. The nanostructure 154 can have any suitable geometric shape as long as the necessary phase distribution of light of different colors can be formed.

[0136] In some embodiments, the nanostructures 154 may be formed of a material including a transparent conductive material, such as indium tin oxide (ITO), tin oxide (SnO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), indium tin zinc oxide (ITZO), antimony tin oxide (ATO), aluminum-doped zinc oxide (AZO), titanium dioxide (TiO2), other suitable materials, or combinations thereof. In some embodiments, the filler material 152 may be formed of a transparent resin, such as polyethylene terephthalate (PET) resin, polycarbonate (PC) resin, polyimide (PI) resin, polymethylmethacrylate (PMMA), polystyrene resin, other suitable resins, or combinations thereof.

[0137] In the above equation, each D GR and D GB Contains positive and negative offsets. D GR The positive shift of is defined as a shift from the green region (eg, the first green region GR1 or the second green region GR2) toward the red region RR, and D GB The positive shift of is defined as the shift from the green region (eg, the first green region GR1 or the second green region GR2) toward the blue region BR. Figure 4B In the first green region GR1, the longitudinal offset GR1_dy1 and the longitudinal offset GR1_dy2 can both be understood as D GR The "positive offset", and the lateral offset GR1_dx1 and the lateral offset GR1_dx2 can both be understood as D GB The "positive offset" of Figure 4B In the second green region GR2, the lateral offset GR2_dx1 and the lateral offset GR2_dx2 can both be understood as D GR The "positive offset", and the longitudinal offset GR2_dy1 and the longitudinal offset GR2_dy2 can both be understood as D GB of the "positive offset".

[0138] exist Figure 3In the embodiment, all lateral offsets GR1_dx1, GR1_dx2, longitudinal offsets GR1_dy1, and GR1_dy2 within the first green region GR1 are positive offsets. Similarly, all lateral offsets GR2_dx1, GR2_dx2, longitudinal offsets GR2_dy1, and GR2_dy2 within the second green region GR2 are positive offsets.

[0139] Figure 6A The third green region GR3 according to some embodiments of the present disclosure is shown at an incident angle θ i A side view of a portion of the imaging device 100a is shown in FIG. Figure 6B FIG. 1 is a side view of a portion of the imaging device 100 b showing the first green region GR1 at an incident angle θ according to some embodiments of the present disclosure.

[0140] like Figure 6B As shown, the edge of the first green region GR1 is displaced from the corresponding edge of the first green filter G1 by an offset distance of the first green region GR1. The color filter layer 130 includes a first green filter G1 (reference Figure 6B ) of the third green filter G3 (reference Figure 6A The third green region GR3 is above the third green filter G3, and the edge of the third green region GR3 is displaced from the corresponding edge of the third green filter G3 by an offset distance of the third green region GR3, as shown in FIG. Figure 6A As shown. The offset distance of the first green region GR1 and the offset distance of the third green region GR3 satisfy the following equations:

[0141]

[0142] Where S(θ) is the offset distance of the first green region GR1, and S(θ i ) is the offset distance of the third green region GR3. In some embodiments, the offset distance of the first green region GR1 is in the range of 0 nm to 300 nm.

[0143] In some embodiments, the offset distance S(θ) is in the range of about -P1 / 2 to about P1 / 2. In some embodiments, when θ is 0 degrees, the offset distance S(θ) is 0 nm. In some embodiments, when θ is 7.5 degrees, the offset distance S(θ) is 72 nm. In some embodiments, when θ is 15 degrees, the offset distance S(θ) is 157 nm. In some embodiments, when θ is 22.5 degrees, the offset distance S(θ) is 209 nm. In some embodiments, when θ is 30 degrees, the offset distance S(θ) is 291 nm.

[0144] The method for forming the imaging device 100 includes the following steps: forming a photoelectric conversion layer 110; forming an anti-reflection layer 120 on the photoelectric conversion layer 110; forming a color filter layer 130 on the anti-reflection layer 120; forming a dielectric layer 140 on the color filter layer 130; and forming a metasurface layer 150 (including peripheral nanorods 154A and central nanorods 154B) on the dielectric layer 140, wherein the metasurface layer 150 is formed according to the configuration 151b.

[0145] Figure 7 FIG. 7 is a top view of a Metasurface layer 750 according to some embodiments of the present disclosure. Figure 7 Metasurface layer 750 and Figure 3 The difference of the metasurface layer 150 lies in the positions of the central nanorods 154B in the blue region BR, the first green region GR1, the second green region GR2 and the red region RR. Figure 7 The central nanopillar 154B of the embodiment includes a negative offset. In the present disclosure, D GR The negative shift of is defined as a shift from the green region (eg, the first green region GR1 or the second green region GR2) away from the red region RR, and D GB The negative offset of is defined as an offset from the green region (eg, the first green region GR1 or the second green region GR2) away from the blue region BR. Figure 7 In the first green region GR1, the longitudinal offset GR1_dy1 and the longitudinal offset GR1_dy2 can both be understood as D GR The "negative offset", and the lateral offset GR1_dx1 and the lateral offset GR1_dx2 can both be understood as D GB The "negative offset" of Figure 7 In the second green region GR2, the lateral offset GR2_dx1 and the lateral offset GR2_dx2 can both be understood as D GR The "negative offset", and the longitudinal offset GR2_dy1 and the longitudinal offset GR2_dy2 can both be understood as D GB of "negative offset".

[0146] exist Figure 7 In the embodiment, all lateral offsets GR1_dx1, GR1_dx2, longitudinal offsets GR1_dy1, and GR1_dy2 within the first green region GR1 are negative offsets. Similarly, all lateral offsets GR2_dx1, GR2_dx2, longitudinal offsets GR2_dy1, and GR2_dy2 within the second green region GR2 are negative offsets.

[0147] Please refer to Figure 21. In some embodiments, the refractive index of the nanostructures 154 (including the peripheral nanopillars 154A and the central nanopillars 154B) is greater than the refractive index of the filler material 152. In some embodiments, the refractive index of the peripheral nanopillars 154A is equal to the refractive index of the central nanopillars 154B. In some embodiments, the refractive index of the peripheral nanopillars 154A is in a range from about 1.8 to about 3.5, for example, 2.0, 2.5, or 3.0. In some embodiments, the refractive index of the central nanopillars 154B is in a range from about 1.8 to about 3.5, for example, 2.0, 2.5, or 3.0. In some embodiments, the refractive index of the filler material 152 is in a range from about 1.0 to about 1.6, for example, 1.2 or 1.4. In some embodiments, the filler material 152 may be air. It is noteworthy that when the nanostructures 154 are surrounded by ambient air (i.e., the refractive index of the filler material 152 is 1), the maximum difference in refractive index is achieved, resulting in a significantly wider phase distribution. Therefore, it is easier to separate the incident light L according to different wavelengths. In some embodiments, the radius ratios of each central nanorod 154B in the blue region BR, the first green region GR1, the second green region GR2, and the red region RR are different. The size of each central nanorod 154B can be adjusted according to the design requirements of the imaging device 100.

[0148] Please refer again Figure 2 Imaging device 100. In some embodiments, the refractive index of dielectric layer 140 is less than the refractive index of nanostructure 154. In some embodiments, the refractive index of dielectric layer 140 is in a range of about 1.0 to about 1.6, for example, 1.2 or 1.4. In some embodiments, the refractive index of each filter of color filter layer 130 (e.g., blue filter B, first green filter G1, second green filter G2, and red filter R) is greater than the refractive index of grid structure 132. In some embodiments, the refractive index of each filter of color filter layer 130 is in a range of about 1.4 to about 2.3, for example, 1.6, 1.8, 2.0, or 2.2. In some embodiments, the refractive index of grid structure 132 is in a range of about 1.0 to about 1.3, for example, 1.1 or 1.2.

[0149] The present disclosure takes into account the situation where the incident light L is not incident in a vertical direction, and provides a method for forming a metasurface layer, wherein the central nanocolumns in the green region have an additional offset distance compared to the central nanocolumns in the blue region and the red region. The additional offset distance can be calculated by the above equation. The metasurface layer of the present disclosure allows the incident light to have a larger range of incident angles and provides a balanced amount of quantum efficiency for different green pixels in the Bayer array. The disclosed metasurface layer can provide similar amounts of quantum efficiency between different green pixels, thereby avoiding channel separation of different green pixels and improving the performance of the imaging device.

[0150] The features of multiple embodiments are summarized above so that those skilled in the art can better understand the embodiments of the present disclosure. Those skilled in the art will appreciate that the present disclosure can be easily used as a basis for designing or modifying other processes and structures to perform the same purposes and / or achieve the same advantages of the embodiments described herein. Those skilled in the art will also recognize that such equivalent constructions do not depart from the concept and scope of the present disclosure, and that various changes, substitutions, and modifications herein can be made without departing from the concept and scope of the present disclosure.

Claims

1. An imaging device, characterized in that: Include: multiple photodiodes; a color filter layer above the plurality of photodiodes, wherein the color filter layer comprises a blue filter, a red filter, a first green filter, and a second green filter; and a metasurface layer disposed above the color filter layer, wherein the metasurface layer includes a first pixel unit, the first pixel unit including a blue region above the blue filter, a red region above the red filter, a first green region above the first green filter, and a second green region above the second green filter; The first green region includes a first central nanocolumn. From a top view, the first central nanocolumn is displaced from a center of the first green region in a Y-axis direction of the first central nanocolumn by a first longitudinal offset and in an X-axis direction of the first central nanocolumn by a first lateral offset. The second green area includes a second central nanocolumn. From the top view, the second central nanocolumn is displaced from the center of the second green area in the Y-axis direction of the second central nanocolumn by a second longitudinal offset, and in the X-axis direction of the second central nanocolumn by a second lateral offset.

2. The imaging device of claim 1 , wherein the first longitudinal offset and the first lateral offset are determined according to an incident angle and an azimuth angle of the first green area. The incident angle of the first green area is the angle between a first incident light on an upper surface of the first green area and a normal line of the upper surface of the first green area. The azimuth angle of the first green area is the angle between a horizontal axis passing through a center of the metasurface layer and a first connecting line, wherein the first connecting line is located between the center of the first green area and the center of the metasurface layer.

3. The imaging device of claim 2, wherein the metasurface layer further comprises a second pixel unit, wherein the second pixel unit comprises a third green region, the third green region comprises a third central nanopillar, and when viewed from above, the third central nanopillar is displaced from a center of the third green region by a third longitudinal offset in the Y-axis direction of the third central nanopillar and by a third lateral offset in the X-axis direction of the third central nanopillar, wherein the third longitudinal offset and the third lateral offset are determined based on an incident angle and an azimuth angle of the third green region. The incident angle of the third green area is an angle between a second incident light on an upper surface of the third green area and a normal to the upper surface of the third green area. The azimuth angle of the third green area is the angle between the horizontal axis passing through the center of the Metasurface layer and a second connecting line, wherein the second connecting line is located between the center of the third green area and the center of the Metasurface layer. The first longitudinal offset of the first central nanorod and the third longitudinal offset of the third central nanorod satisfy the following equation: Wherein θ is the incident angle of the first green area, and θ is not equal to 0 degrees, is the azimuth of the first green area, is the first longitudinal offset of the first central nanorod, θ i is the incident angle of the third green area, and θ i Not equal to 0 degrees, is the azimuth of the third green area, is the third longitudinal offset of the third central nanorod, Δθ is a first difference between the incident angle of the first green region and the incident angle of the third green region, and is a second difference between the azimuth angle of the first green area and the azimuth angle of the third green area.

4. The imaging device of claim 3 , wherein the first lateral offset of the first central nanorod and the third lateral offset of the third central nanorod satisfy the following equation: in is the first lateral offset of the first central nanorod, and is the third lateral offset of the third central nanorod.

5. The imaging device of claim 4 , wherein an edge of the first green region is displaced from a corresponding edge of the first green filter by an offset distance of the first green region, the color filter layer comprises a third green filter adjacent to the first green filter, the third green region is above the third green filter, and an edge of the third green region is displaced from a corresponding edge of the third green filter by the offset distance of the third green region. The offset distance of the first green area and the offset distance of the third green area satisfy the following equation: Where S(θ) is the offset distance of the first green area, and S(θ i ) is the offset distance of the third green region, wherein the offset distance of the first green region is in the range of 0 nm to 300 nm, and θ is greater than 0 degrees and ≤ 35 degrees, In the range of 0 degrees to 360 degrees.

6. The imaging device of claim 1 , wherein the metasurface layer further comprises a plurality of peripheral nanorods and a filling material, wherein the plurality of peripheral nanorods are located at corners of the blue region, the red region, the first green region, and the second green region, and the filling material laterally surrounds the first central nanorod and the second central nanorod, wherein the refractive index of the filling material is in the range of 1.0 to 1.

6. The imaging device further includes a dielectric layer disposed between the color filter layer and the blue filter, the red filter, the first green filter, and the second green filter. The size of each of the blue region, the red region, the first green region, and the second green region is in the range of 400 nm to 700 nm, and the refractive index of the first central nanorod is in the range of 1.8 to 3.

5.

7. The imaging device as claimed in claim 1, wherein the first longitudinal offset of the first central nanorod is within 1 / 5 of the size of the first green filter, and the first lateral offset of the first central nanorod is within 1 / 5 of the size of the first green filter.

8. The imaging device of claim 1 , wherein the first longitudinal offset and the first lateral offset comprise positive offsets, and the second longitudinal offset and the second lateral offset comprise positive offsets. wherein the positive offset of the first longitudinal offset is defined as an offset from the first green area toward the red area, and the positive offset of the first lateral offset is defined as an offset from the first green area toward the blue area, The positive offset of the second longitudinal offset is defined as an offset from the second green area toward the blue area, and the positive offset of the second lateral offset is defined as an offset from the second green area toward the red area.

9. The imaging device of claim 1 , wherein the first longitudinal offset and the first lateral offset comprise negative offsets, and the second longitudinal offset and the second lateral offset comprise negative offsets. wherein the negative offset of the first longitudinal offset is defined as an offset from the first green area away from the red area, and the negative offset of the first lateral offset is defined as an offset from the first green area away from the blue area, The negative offset of the second longitudinal offset is defined as an offset from the second green area away from the blue area, and the negative offset of the second lateral offset is defined as an offset from the second green area away from the red area.

10. A method for forming an imaging device, characterized in that: Include: providing a plurality of photodiodes; forming a color filter layer above the plurality of photodiodes, wherein the color filter layer comprises a blue filter, a red filter, a first green filter, and a second green filter; and Forming a metasurface layer above the color filter layer, wherein the metasurface layer includes a first pixel unit, the first pixel unit including a blue region above the blue filter, a red region above the red filter, a first green region above the first green filter, and a second green region above the second green filter, wherein the first green region includes a first central nanorod, and the second green region includes a second central nanorod. Forming the metasurface layer includes: forming the first central nanocolumn, wherein, from a top view, the first central nanocolumn is displaced from a center of the first green region in a Y-axis direction of the first central nanocolumn by a first longitudinal offset and in an X-axis direction of the first central nanocolumn by a first lateral offset; and The second central nanocolumn is formed, wherein, viewed from a top view, the second central nanocolumn is displaced from a center of the second green region in the Y-axis direction by a second longitudinal offset and in the X-axis direction by a second lateral offset.

Images