Image sensor and forming method thereof

Abstract

The invention discloses an image sensor and a forming method thereof, and the structure comprises a substrate, the substrate comprises a plurality of pixel regions which are arranged in an array, and one pixel region comprises four sub-regions which are distributed in a shape like a Chinese character'tian '; the plurality of filter layers are located on the pixel regions, one filter layer is located on two adjacent sub-regions of one pixel region, and the filter layers are separated from each other; the plurality of lens structures are positioned on the light filtering layer, the lens structures are in one-to-one correspondence with the light filtering layer, one lens structure is positioned on two adjacent sub-regions of one pixel region, and each lens structure comprises a first part and a second part positioned on the first part; the projection of the second part on the substrate is located in the projection range of the first part on the substrate. The image sensor has higher resolution capability on phase information during automatic focusing of phase detection, and can better realize global phase focusing.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to an image sensor and a method for forming the same. Background Art

[0002] Image sensors are the core components of camera equipment, which realize image capture by converting optical signals into electrical signals. Taking CMOS Image Sensors (CIS) devices as an example, they have been widely used in various fields due to their advantages of low power consumption and high signal-to-noise ratio.

[0003] Taking the back-side illumination (BSI) CIS as an example, in the existing manufacturing process, logic devices and pixel devices are first formed in the semiconductor substrate and a metal interconnection structure is formed on the surface of the semiconductor substrate. Then, a carrier wafer is bonded to the front side of the semiconductor substrate, and the back side of the semiconductor substrate is thinned. Then, subsequent processes of the CIS are formed on the back side of the semiconductor substrate, such as forming a grid on the back side of the semiconductor substrate of the pixel device, and forming a color filter matrix in the grids between the grids.

[0004] Taking the front-side illumination (FSI) CIS as an example, in the existing manufacturing process, logic devices and pixel devices are first formed in the semiconductor substrate and a metal interconnection structure is formed on the surface of the semiconductor substrate. Then, a grid-like grid is formed on the surface of the metal interconnection structure, and a color filter matrix is ​​formed in the grids between the grids.

[0005] In the prior art, in order to improve the performance of optical image sensors, phase detection auto focus (PDAF) technology is used for focusing. PDAF technology focuses based on the principle of phase difference, which helps to increase the focusing speed, improve the focusing effect, and determine the correct position of the lens to avoid making the image out of focus, which causes the optical image sensor to malfunction.

[0006] However, in the prior art, the focusing effect of the PDAF technology is affected due to the difference in focusing spots at different positions of the image sensor. Summary of the invention

[0007] The technical problem solved by the present invention is to provide an image sensor and a method for forming the same, so as to improve the focusing effect of the PDAF technology.

[0008] To solve the above technical problems, the technical solution of the present invention provides an image sensor, including: a substrate, the substrate includes a plurality of pixel regions arranged in an array, and one pixel region includes 4 sub-regions distributed in a "field" shape; a plurality of filter layers located on the pixel regions, one filter layer is located on two adjacent sub-regions of one pixel region, and each filter layer is separated from each other; a plurality of lens structures located on the filter layers, the lens structures correspond to the filter layers one by one, one lens structure is located on two adjacent sub-regions of one pixel region, the lens structure includes a first part and a second part located on the first part, and the projection of the second part on the substrate is within the projection range of the first part on the substrate.

[0009] Optionally, the first part includes an ellipsoidal shape protruding from the filter layer, and the second part includes an ellipsoidal shape protruding from the first part.

[0010] Optionally, the first part has a first length, a first width, and a first height, the second part has a second length, a second width, and a second height, the ratio range of the second length to the first length is 0.35 to 0.75, the ratio range of the second width to the first width is 0.15 to 0.6, and the ratio range of the second height to the first height is 0.3 to 0.85.

[0011] Optionally, the filter layer includes a red filter layer, a green filter layer, or a blue filter layer, and the filter layers on the 4 sub-regions of one pixel region have the same color.

[0012] Optionally, the substrate includes a plurality of pixel units arranged in an array, one pixel unit includes a first pixel region, a second pixel region, a third pixel region, and a fourth pixel region, the first pixel region and the second pixel region are arranged along a first direction parallel to the surface of the substrate, the third pixel region and the fourth pixel region are arranged along the first direction, the first pixel region and the third pixel region are adjacent in a second direction parallel to the surface of the substrate, the second pixel region and the fourth pixel region are adjacent in the second direction, the first direction and the second direction are perpendicular, the first pixel region includes 4 first sub-regions distributed in a "field" shape, the second pixel region includes 4 second sub-regions distributed in a "field" shape, the third pixel region includes 4 third sub-regions distributed in a "field" shape, the fourth pixel region includes 4 fourth sub-regions distributed in a "field" shape; a first filter layer is provided on the first pixel region, a second filter layer is provided on the second pixel region, a third filter layer is provided on the third pixel region, a fourth filter layer is provided on the fourth pixel region, the colors of the first filter layer, the second filter layer, and the fourth filter layer are different from each other, and the colors of the adjacent first filter layer, second filter layer, third filter layer, and fourth filter layer are different.

[0013] Optionally, in each pixel unit, the arrangement direction of the lens structure on the pixel area of ​​at least one color filter layer is the same, and the arrangement direction of the lens structure includes parallel to the first direction, or parallel to the second direction, including: the arrangement direction of the lens structure on the pixel area of ​​the red filter layer in each pixel unit is the same, the arrangement direction of the lens structure on the pixel area of ​​the blue filter layer in each pixel unit is the same, and the arrangement direction of the lens structure on the pixel area of ​​the green filter layer in each pixel unit is the same, one or more of the three situations.

[0014] Optionally, the arrangement direction of the lens structure on the first pixel area of ​​each pixel unit is the same, the arrangement direction of the lens structure on the second pixel area of ​​each pixel unit is the same, the arrangement direction of the lens structure on the third pixel area of ​​each pixel unit is the same, and the arrangement direction of the lens structure on the fourth pixel area of ​​each pixel unit is the same.

[0015] Optionally, the lens structures on the first pixel region, the second pixel region, the third pixel region and the fourth pixel region are arranged in the same direction.

[0016] Optionally, the arrangement directions of the lens structures on the adjacent first pixel area, second pixel area, third pixel area and fourth pixel area are different from each other, the lens arrangement direction on the first pixel area is the same as the lens arrangement direction on the fourth pixel area, and the lens arrangement direction on the second pixel area is the same as the lens arrangement direction on the third pixel area; or, the lens arrangement directions on the second pixel area, the third pixel area and the fourth pixel area are the same, and the lens arrangement direction on the first pixel area is different from the lens arrangement directions on the second pixel area, the third pixel area and the fourth pixel area.

[0017] Optionally, the arrangement directions of the lens structures on the first pixel area and the second pixel area arranged along the first direction are different, the arrangement directions of the lens structures on the first pixel area and the third pixel area arranged along the second direction are the same, and the arrangement directions of the lens structures on the second pixel area and the fourth pixel area arranged along the second direction are the same.

[0018] Optionally, the arrangement directions of the lens structures on the first pixel region, the second pixel region, the third pixel region and the fourth pixel region in one pixel unit are the same, and the arrangement directions of the lens structures on two adjacent pixel units are different.

[0019] Optionally, the arrangement directions of the lens structures on the first pixel area, the second pixel area, the third pixel area and the fourth pixel area within a pixel unit are the same, the arrangement directions of the lens structures on two adjacent pixel units arranged along the first direction are different, and the arrangement directions of the lens structures on two adjacent pixel units arranged along the second direction are the same.

[0020] Optionally, the color of the first filter layer includes blue, the color of the second filter layer includes green, the color of the third filter layer includes green, and the color of the fourth filter layer includes red.

[0021] Optionally, the colors of the filter layers on the pixel areas in a row or a column are the same, and the colors of the filter layers on the pixel areas in two adjacent rows or columns are different from each other; the arrangement directions of the lens structures on the two adjacent pixel areas in the first row or the first column are different, and the arrangement directions of the lens structures on the pixel areas in the second row or the second column adjacent to the first row or the first column are the same.

[0022] Optionally, the substrate further includes a plurality of isolation regions, wherein the isolation regions are located between adjacent sub-regions and surround the sub-regions; and further includes: an isolation structure located in the isolation region, wherein the isolation structure surrounds the sub-regions.

[0023] Optionally, it also includes: a dielectric structure located on the substrate, the filter layer is located on the dielectric structure; a grid structure located on the dielectric structure on part of the isolation area, the grid structure forms a groove spanning two adjacent sub-areas, the filter layer is located in the groove, and the grid structure isolates adjacent filter layers.

[0024] Optionally, it also includes: a photosensitive structure located in the sub-area; the photosensitive structure includes a photodiode.

[0025] Optionally, the first part and the second part are made of the same material.

[0026] Optionally, the refractive index range of the material of the first part is greater than 1.55; the refractive index range of the material of the second part is greater than 1.55; the material of the first part includes organic material, the organic material includes resin, the resin includes carbonate or polyacrylate; the material of the second part includes organic material, the organic material includes resin, the resin includes carbonate or polyacrylate.

[0027] Optionally, it also includes: an anti-reflection layer located on the surface of the lens structure.

[0028] Accordingly, the technical solution of the present invention further provides a method for forming the above image sensor, including: providing a substrate, the substrate including a plurality of pixel regions arranged in an array, one pixel region including 4 sub-regions distributed in a "field" shape; forming a plurality of filter layers on the pixel regions, one filter layer being located on two adjacent sub-regions of one pixel region, and each filter layer being separate from each other; forming a plurality of lens structures on the filter layers, the lens structures corresponding to the filter layers one by one, one lens structure being located on two adjacent sub-regions of one pixel region, the lens structure including a first part and a second part located on the first part, and the projection of the second part on the substrate being within the projection range of the first part on the substrate.

[0029] Optionally, the substrate further includes a plurality of isolation regions, the isolation regions being located between adjacent sub-regions and surrounding the sub-regions; further including: forming an isolation structure in the isolation regions, the isolation structure surrounding the sub-regions; and forming a photosensitive structure in the sub-regions.

[0030] Optionally, before forming the filter layer on the pixel region, it further includes: forming a dielectric structure on the substrate, the filter layer being located on the dielectric structure; forming a grid structure on the dielectric structure in part of the isolation regions, the grid structure enclosing a groove spanning two adjacent sub-regions; the method for forming the filter layer includes: filling a filter material layer in the groove; planarizing the filter material layer to form the filter layer in the groove, and the grid structure isolating adjacent filter layers.

[0031] Optionally, the method for forming the lens structure includes: forming a lens material layer on the grid structure and the filter layer; forming a first mask layer on the lens material layer, the first mask layer being an ellipsoidal shape protruding from the filter layer and located on two adjacent sub-regions of one pixel region; forming a second mask layer on the first mask layer, the second mask layer being an ellipsoidal shape protruding from the first mask layer, and the projection of the second mask layer on the substrate being within the projection range of the first mask layer on the substrate; etching the lens material layer using the second mask layer and the first mask layer as masks to form a lens structure located on the filter layer, the lens structure including a first part and a second part located on the first part, and the projection of the second part on the substrate being within the projection range of the first part on the substrate.

[0032] Optionally, the method for forming the first mask layer includes: forming an initial first mask layer on the lens material layer, the initial first mask layer being located on two adjacent sub-regions of one pixel region; performing a reflow process on the initial first mask layer to form the first mask layer on the lens material layer.

[0033] Optionally, the method for forming the second mask layer includes: forming an initial second mask layer on the first mask layer, the projection of the initial second mask layer on the substrate being within the projection range of the first mask layer on the substrate; and reflowing the initial second mask layer to form the second mask layer on the first mask layer.

[0034] Optionally, the material of the first mask layer and the material of the second mask layer are the same as the material of the lens structure; the material of the first mask layer and the second mask layer include organic materials, the organic materials include resins, and the resins include carbonate or polyacrylate.

[0035] Optionally, the method further includes: forming an anti-reflection layer on the surface of the lens structure.

[0036] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0037] The formation method and structure of the present invention, a filter layer is located on two adjacent sub-areas of a pixel area, a lens structure is located on two adjacent sub-areas of a pixel area, the lens structure corresponds to the filter layer one by one, the lens structure includes a first part and a second part located on the first part, and the lens structure with two parts improves the sensitivity of the image sensor to light, and the light spot is easily gathered at the junction of two adjacent sub-areas, rather than the central position of the four sub-areas, so that the requirements for alignment accuracy are low, and the requirements for process are relatively low. That is, under the condition of lower alignment accuracy, the requirements for the resolution ability of phase information during higher phase detection autofocus can also be met, and global phase focusing can be better achieved.

[0038] Furthermore, the first part is an ellipsoid protruding from the filter layer, the second part is an ellipsoid protruding from the first part, and a lens structure is located on two adjacent sub-areas of a pixel area. The light spot converged by the lens structure is in the shape of a long strip, and the long strip light spot is located at the junction of the two adjacent sub-areas, and the area of ​​the long strip light spot is large. Therefore, when forming the lens structure, the size accuracy and position accuracy of the lens structure can have a larger deviation range, thereby improving the process tolerance for forming the lens structure.

[0039] Furthermore, the ratio of the second length to the first length is in the range of 0.35 to 0.75, the ratio of the second width to the first width is in the range of 0.15 to 0.6, and the ratio of the second height to the first height is in the range of 0.3 to 0.85. The lens structure composed of the first part and the second part within the size range can better achieve global phase focusing.

[0040] Furthermore, in each pixel unit, the arrangement direction of the lens structure on the pixel area of ​​at least one color filter layer is the same, and the arrangement direction of the lens structure includes parallel to the first direction or parallel to the second direction, including: the arrangement direction of the lens structure on the pixel area of ​​the red filter layer in each pixel unit is the same, the arrangement direction of the lens structure on the pixel area of ​​the blue filter layer in each pixel unit is the same, and the arrangement direction of the lens structure on the pixel area of ​​the green filter layer in each pixel unit is the same, or one or more of the three situations. Therefore, when the image sensor performs algorithm planning, the pixel algorithms corresponding to the same color filter layer are the same, which can optimize the processing process of the algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figures 1 to 3 is a schematic diagram of the structure of an image sensor in one embodiment;

[0042] Figures 4 to 20 is a structural schematic diagram of an image sensor forming process in one embodiment of the present invention;

[0043] Figure 21 to Figure 24 is a schematic structural diagram of an image sensor in another embodiment of the present invention;

[0044] Figure 25 to Figure 28 is a schematic structural diagram of an image sensor in another embodiment of the present invention;

[0045] Figure 29 to Figure 32 is a schematic structural diagram of an image sensor in another embodiment of the present invention;

[0046] Fig.33 is a schematic structural diagram of an image sensor in another embodiment of the present invention;

[0047] Fig.34 is a schematic structural diagram of an image sensor in another embodiment of the present invention;

[0048] Fig.35 is a schematic structural diagram of an image sensor in another embodiment of the present invention. DETAILED DESCRIPTION

[0049] As described in the background technology, the focusing effect of PDAF technology needs to be improved. Now, an analysis and explanation will be given in conjunction with a specific embodiment.

[0050] Figures 1 to 3 is a schematic diagram of the structure of an image sensor in one embodiment.

[0051] Please refer to Figures 1 to 3 , Figure 1 is a top view of the pixel array, Figure 2 is a schematic diagram of a pixel unit P, Figure 3 for Figure 2Schematic cross-sectional structure diagram along the direction of section line AA1. The image sensor includes: a substrate 100, the substrate 100 includes a number of pixel units P arranged in an XY array. One pixel unit P includes a first pixel region 101, a second pixel region 102, a third pixel region 103, and a fourth pixel region 104. The first pixel region 101 and the second pixel region 102 in one pixel unit P are arranged along a first direction X parallel to the surface of the substrate 100. The third pixel region 103 and the fourth pixel region 104 are arranged along the first direction X. The first pixel region 101 and the third pixel region 103 are adjacent in a second direction Y parallel to the surface of the substrate 100. The second pixel region 102 and the fourth pixel region 104 are adjacent in the second direction Y. The first direction X and the second direction Y are perpendicular. The first pixel region 101 includes 4 first sub-regions 1011 distributed in a "field" shape. The second pixel region 102 includes 4 second sub-regions 1021 distributed in a "field" shape. The third pixel region 103 includes 4 third sub-regions distributed in a "field" shape. The fourth pixel region 104 includes 4 fourth sub-regions distributed in a "field" shape. An isolation structure 105 located between adjacent sub-regions. A photosensitive structure located within the sub-regions. A first filter layer 110 located on the first pixel region 101, a second filter layer 111 located on the second pixel region 102, a third filter layer 112 located on the third pixel region 103, a fourth filter layer 113 located on the fourth pixel region 104. One filter layer is located on the 4 sub-regions of one pixel region, and each filter layer is separated from each other. A grid structure 109 located between adjacent filter layers. A number of lens structures 116 located on the filter layers. One lens structure 116 is located on one filter layer.

[0052] In the image sensor, the color of the first filter layer 110 includes blue, the color of the second filter layer 111 includes green, the color of the third filter layer 112 includes green, and the color of the fourth filter layer 113 includes red. The first filter layer 110 is located on the 4 first sub-regions 1011 of the first pixel region 101. The second filter layer 111 is located on the 4 second sub-regions 1021 of the second pixel region 102. The third filter layer 112 is located on the 4 third sub-regions of the third pixel region 103. The fourth filter layer 113 is located on the 4 fourth sub-regions of the fourth pixel region 104.

[0053] Since the lens structures 116 on the first filter layer 110, the second filter layer 111, the third filter layer 112, and the fourth filter layer 113 need to converge light into 4 sub-regions respectively, the lens structures 116 are hemispherical. The lens structures 116 are relatively large in size and have strong light-converging ability. The converged light forms a small-area light spot at the position where the 4 sub-regions meet (i.e., the center position of a pixel region). This requires the lens structures 116 to have relatively precise position accuracy to ensure that the light spot is formed at the position where the 4 sub-regions meet. Otherwise, when the light spot shifts, it will cause uneven light intensity distribution among the 4 sub-regions under the same filter layer, resulting in obvious differences, which will further affect global phase focusing. In addition, since the lens structures 116 need relatively precise position accuracy to ensure that the light spot is formed at the position where the 4 sub-regions meet, the forming process requirements for the lens structures 116 are higher. Correspondingly, the forming process requirements for the structures below the lens structures 116 will also increase accordingly, and the process window becomes smaller.

[0054] To solve the above problems, the technical solution of the present invention provides an image sensor and a method for forming the same. One filter layer is located on two adjacent sub-regions of a pixel region, and one lens structure is located on two adjacent sub-regions of a pixel region. The lens structures correspond to the filter layers one by one. The lens structure includes a first part and a second part located on the first part. The lens structure with two parts improves the sensitivity of the image sensor to light, and the light spot is easily converged to the junction of two adjacent sub-regions instead of the central position of four sub-regions, thus requiring low alignment accuracy and relatively low process requirements. That is, under the condition of relatively low alignment accuracy, it can also meet the requirement for the resolution ability of phase information during high-precision phase detection autofocus, and can better achieve global phase focusing.

[0055] To make the above objects, features, and beneficial effects of the present invention more obvious and understandable, the following specifically describes the embodiments of the present invention in detail with reference to the drawings.

[0056] Figures 4 to 20 It is a schematic structural diagram of the process of forming an image sensor in an embodiment of the present invention.

[0057] Please refer to Figures 4 to 6 , Figure 4 which is a top view of a pixel array, Figure 5 is a schematic diagram of a pixel unit, Figure 6 is Figure 5 a schematic cross-sectional structure diagram along the section line AA1 direction in

[0058] In this embodiment, the principal ray angle (CRAmax) of the optical imaging lens of the image sensor is 33.84 degrees, 35.84 degrees, and 36.41 degrees; the pixel region is square, and the side length range of the pixel region is from 0.56 micrometers to 1.12 micrometers.

[0059] In this embodiment, the substrate 200 includes a plurality of pixel units P arranged in an XY array (refer to Figure 2 ), and one pixel unit P includes a first pixel region 201, a second pixel region 202, a third pixel region 203, and a fourth pixel region 204. The plurality of pixel regions arranged in an array include a plurality of first pixel regions 201, second pixel regions 202, third pixel regions 203, and fourth pixel regions 204 arranged in an array.

[0060] In this embodiment, the first pixel region 201 and the second pixel region 202 in one pixel unit P are arranged along a first direction X parallel to the surface of the substrate 200, the third pixel region 203 and the fourth pixel region 204 are arranged along the first direction X, the first pixel region 201 and the third pixel region 203 are adjacent in a second direction Y parallel to the surface of the substrate 200, the second pixel region 202 and the fourth pixel region 204 are adjacent in the second direction Y, the first direction X and the second direction Y are perpendicular, and the first pixel region 201, the second pixel region 202, the third pixel region 203, and the fourth pixel region 204 are distributed in a "field" shape.

[0061] In this embodiment, the first pixel region 201 includes 4 first sub-regions 2011 distributed in a "field" shape, the second pixel region 202 includes 4 second sub-regions 2021 distributed in a "field" shape, the third pixel region 203 includes 4 third sub-regions 2031 distributed in a "field" shape, and the fourth pixel region 204 includes 4 fourth sub-regions 2041 distributed in a "field" shape.

[0062] The arrangement manners of the 4 first sub-regions 2011, the 4 second sub-regions 2021, the 4 third sub-regions 2031, and the 4 fourth sub-regions 2041 are the same as the arrangement manner of the first pixel region 201, the second pixel region 202, the third pixel region 203, and the fourth pixel region 204.

[0063] Please continue to refer to Figure 6 , in this embodiment, the substrate 200 further includes a plurality of isolation regions (not labeled), the isolation regions are located between adjacent sub-regions, and the isolation regions surround the sub-regions.

[0064] In this embodiment, the isolation region is located between adjacent first sub-regions 2011, between adjacent second sub-regions 2021, between adjacent third sub-regions 2031, between adjacent fourth sub-regions 2041, and between adjacent first sub-regions 2011 and second sub-regions 2021, between adjacent first sub-regions 2011 and third sub-regions 2031, between adjacent second sub-regions 2021 and third sub-regions 2031, and between adjacent fourth sub-regions 2041 and third sub-regions 2031, and the isolation region surrounds the first sub-region 2011, the second sub-region 2021, the third sub-region 2031, and the fourth sub-region 2041.

[0065] Please continue to refer to Figure 6 , and also includes: forming an isolation structure 205 in the isolation area, wherein the isolation structure 205 surrounds the first sub-area 2011, the second sub-area 2021, the third sub-area 2031 and the fourth sub-area 2041; and forming a photosensitive structure (not shown) in the first sub-area 2011, the second sub-area 2021, the third sub-area 2031 and the fourth sub-area 2041.

[0066] The isolation structure 205 is used to isolate each sub-region from adjacent sub-regions to prevent optical crosstalk and electrical crosstalk from occurring in adjacent sub-regions.

[0067] In this embodiment, the material of the isolation structure 205 includes a dielectric material, and the dielectric material includes a combination of one or more of silicon oxide, silicon nitride, silicon carbide, silicon oxycarbide, silicon oxynitride, aluminum oxide, aluminum nitride, tantalum oxide, hafnium oxide, silicon carbide nitride and silicon oxycarbon nitride.

[0068] In this embodiment, the photosensitive structure includes a photosensitive diode.

[0069] In this embodiment, the material of the substrate 200 includes silicon.

[0070] In other embodiments, the substrate material includes silicon carbide, silicon germanium, a multinary semiconductor material composed of group III-V elements, silicon on insulator (SOI) or germanium on insulator (GOI). Among them, the multinary semiconductor material composed of group III-V elements includes InP, GaAs, GaP, InAs, InSb, InGaAs or InGaAsP.

[0071] Please refer to Figure 7 , Figure 7 For Figure 6 Based on the schematic diagram, a dielectric structure is formed on the substrate 200, and a grid structure 209 is formed on the dielectric structure on part of the isolation region, and the grid structure 209 constitutes a groove 230 spanning two adjacent sub-regions.

[0072] The dielectric structure includes one or more dielectric layers, and the material of the dielectric layer includes one or more combinations of silicon oxide, hafnium oxide, silicon nitride and aluminum oxide. The dielectric structure is a transparent material so that light can pass through the dielectric structure to reach the pixel area. In addition, the dielectric structure also plays an insulating role to avoid electrical crosstalk.

[0073] In this embodiment, the dielectric structure includes a first dielectric layer 206 , a second dielectric layer 207 located on the first dielectric layer 206 , and a third dielectric layer 208 located on the second dielectric layer 207 . The materials of the first dielectric layer 206 , the second dielectric layer 207 and the third dielectric layer 208 are different from each other.

[0074] In this embodiment, the material of the first dielectric layer 206 includes aluminum oxide, the material of the second dielectric layer 207 includes hafnium oxide, and the material of the third dielectric layer 208 includes silicon oxide.

[0075] The grid structure 209 is used to isolate the filter layers subsequently formed on the dielectric structure to avoid light crosstalk in adjacent filter layers.

[0076] In this embodiment, the material of the grid structure 209 includes metal, dielectric material, or a composite material of metal and dielectric material.

[0077] Please refer to Figures 8 to 11 , Figure 8 is a top view of the pixel array, Fig. 9 is a schematic diagram of a pixel unit P, Fig.10 for Fig. 9 Schematic diagram of the cross-sectional structure along the section line AA1, Fig.11 for Fig. 9 The schematic cross-sectional structure diagram along the section line BB1 ​​direction in the figure shows that a plurality of filter layers are formed on the pixel area, one filter layer is located on two adjacent sub-areas of a pixel area, each filter layer is separate from each other, and the filter layer is located on the dielectric structure.

[0078] The method for forming the filter layer includes: filling a filter material layer (not shown) in the groove 230 ; flattening the filter material layer, and forming the filter layer in the groove 230 , wherein the grid structure 209 isolates adjacent filter layers.

[0079] The grooves are located on two adjacent sub-regions of a pixel region, and a grid structure 209 is provided between the grooves for isolation.

[0080] The filter layer includes a red filter layer, a green filter layer or a blue filter layer, and the filter layers on the four sub-areas of one pixel area have the same color.

[0081] In this embodiment, the color of the filter layers on the four first sub-areas 2011 of the first pixel area 201 is the same, the color of the filter layers on the four second sub-areas 2021 of the second pixel area 202 is the same, the color of the filter layers on the four third sub-areas 2031 of the third pixel area 203 is the same, and the color of the filter layers on the four fourth sub-areas 2041 of the fourth pixel area 204 is the same.

[0082] In this embodiment, a first filter layer 210 is provided on the first pixel area 201, a second filter layer 211 is provided on the second pixel area 202, a third filter layer 212 is provided on the third pixel area 203, and a fourth filter layer 213 is provided on the fourth pixel area 204. The colors of the first filter layer 210, the second filter layer 211 and the fourth filter layer 213 are different from each other, and the colors of adjacent first filter layers 210, second filter layers 211, third filter layers 212 and fourth filter layers 213 are different.

[0083] In this embodiment, the color of the first filter layer 210 includes blue, the color of the second filter layer 211 includes green, the color of the third filter layer 212 includes green, and the color of the fourth filter layer 213 includes red.

[0084] In other embodiments, the colors of the first filter layer, the second filter layer, the third filter layer and the fourth filter layer may also be other combinations.

[0085] One filter layer is located on two adjacent sub-areas of a pixel area, and each filter layer is separated from each other. A pixel area has two filter layers with length directions parallel to each other, and the length direction of the filter layer is parallel to the first direction X or the second direction Y. A grid structure 209 is provided between each filter layer for isolation.

[0086] In this embodiment, the first filter layer 210 is located on the first sub-area 2011 adjacent to the first direction X, and the first pixel area 201 has two first filter layers 210 with length directions parallel to the first direction X; the second filter layer 211 is located on the second sub-area 2021 adjacent to the first direction X, and the second pixel area 202 has two second filter layers 211 with length directions parallel to the first direction X; the third filter layer 212 is located on the third sub-area 2031 adjacent to the first direction X, and the third pixel area 203 has two third filter layers 212 with length directions parallel to the first direction X; the fourth filter layer 213 is located on the fourth sub-area 2041 adjacent to the first direction X, and the fourth pixel area 204 has two fourth filter layers 213 with length directions parallel to the first direction X.

[0087] The grid structure 209 isolates the adjacent first filter layer 210 , second filter layer 211 , third filter layer 212 , and fourth filter layer 213 to avoid optical crosstalk.

[0088] Next, a plurality of lens structures are formed on the filter layer. The lens structures correspond to the arrangement directions of the filter layer one by one. One lens structure is located on two adjacent sub-areas of a pixel area. The lens structure includes a first part and a second part located on the first part. The projection of the second part on the substrate 200 is located within the projection range of the first part on the substrate 200. Please refer to the formation process of the lens structure. Figures 12 to 20 .

[0089] A filter layer has a lens structure on it, and a filter layer under the lens structure is not blocked by the grid structure 209, so as to prevent the grid structure 209 from blocking the incident light and affecting the phase signal of each sub-area.

[0090] Please refer to Fig.12 , Fig.12 For Fig.10 Based on the schematic diagram, a flat layer 214 is formed on the grid structure 209 and the filter layer; a lens material layer 215 is formed on the flat layer 214; an initial first mask layer 216 is formed on the lens material layer 215, and the initial first mask layer 216 is located on two adjacent sub-areas of a pixel area.

[0091] The flat layer 214 is used to provide support for the lens structure formed subsequently and to provide a flat surface. The material of the flat layer 214 includes a light-transmitting material, and the light-transmitting material includes silicon oxide, resin, and the like.

[0092] In this embodiment, the material of the planar layer 214 includes silicon oxide.

[0093] The method for forming the flat layer 214 includes: forming a flat material layer on the grid structure 209 and the filter layer; and flattening the flat material layer to form the flat layer 214 .

[0094] In this embodiment, the process of forming the planar material layer includes a chemical vapor deposition process, and the process of planarizing the planar material layer includes a chemical mechanical polishing process.

[0095] The material of the initial first mask layer 216 includes an organic material, the organic material includes a resin, and the resin includes carbonate or polyacrylate.

[0096] The process of forming the initial first mask layer 216 includes a spin coating or a spray coating process.

[0097] In this embodiment, the material of the initial first mask layer 216 is the same as that of the lens material layer 215 .

[0098] The lens material layer 215 is used to subsequently form a lens structure. The lens structure includes a first portion and a second portion located on the first portion. The first portion and the second portion are made of the same material. The lens material layer is a layer of material formed in one process.

[0099] In other embodiments, the materials of the first part and the second part may be different, so the lens material layer is composed of two different material layers, and the two different material layers are formed by two different processes.

[0100] Please refer to Fig.13 The initial first mask layer 216 is reflowed to form the first mask layer 217 on the lens material layer 215. The first mask layer 217 is an ellipsoid protruding from the filter layer. The first mask layer 217 is located on two adjacent sub-areas of a pixel area.

[0101] The reflow process includes: performing a heat treatment on the initial first mask layer 216 to melt the initial first mask layer 216 into a fluid state, and forming an ellipsoidal first mask layer 217 protruding from the filter layer after natural flow and cooling.

[0102] Please refer to Fig.14 , an initial second mask layer 218 is formed on the first mask layer 217 , and a projection of the initial second mask layer 218 on the substrate 200 is located within a projection range of the first mask layer 217 on the substrate 200 .

[0103] The projection of the initial second mask layer 218 on the substrate 200 is located within the projection range of the first mask layer 217 on the substrate 200, that is, the dimensions of the initial second mask layer 218 in the first direction X and the second direction Y are smaller than the dimensions of the first mask layer 217 in the same directions.

[0104] The material of the initial second mask layer 218 includes an organic material, the organic material includes a resin, and the resin includes carbonate or polyacrylate.

[0105] The process of forming the initial second mask layer 218 includes a spin coating or a spray coating process.

[0106] In this embodiment, the material of the initial second mask layer 218 is the same as that of the lens material layer 215 .

[0107] Please refer to Fig.15, the initial second mask layer 218 is reflowed to form the second mask layer 219 on the first mask layer 217, the second mask layer 219 is an ellipsoid protruding from the first mask layer 217, and the projection of the second mask layer 219 on the substrate 200 is located within the projection range of the first mask layer 217 on the substrate 200.

[0108] The reflow treatment includes: performing a heat treatment on the initial second mask layer 218 to melt the initial second mask layer 218 into a fluid state, and forming an ellipsoidal second mask layer 219 protruding from the first mask layer 217 after natural flow and cooling.

[0109] The projection of the second mask layer 219 on the substrate 200 is located within the projection range of the first mask layer 217 on the substrate 200, that is, the dimensions of the second mask layer 219 in the first direction X and the second direction Y are smaller than the dimensions of the first mask layer 217 in the same directions.

[0110] Please refer to Figures 16 to 20 , Fig.16 is a top view of the pixel array, Fig.17 is a schematic diagram of a pixel unit P, Fig.18 for Fig.17 Schematic diagram of the cross-sectional structure along the section line AA1, Fig.19 for Fig.17 The schematic diagram of the cross-sectional structure along the section line BB1, Fig. 20 It is an enlarged schematic diagram of the lens structure. The lens material layer 215 is etched using the second mask layer 219 and the first mask layer 217 as masks to form a lens structure located on the filter layer. The lens structure includes a first part 220 and a second part 221 located on the first part 220. The projection of the second part 221 on the substrate 200 is located within the projection range of the first part 220 on the substrate 200.

[0111] The material of the initial first mask layer 216 and the material of the initial second mask layer 218 are the same as the material of the lens material layer 215, and the material of the mask structure including the second mask layer 219 and the first mask layer 217 formed by two reflows is also the same as the material of the lens material layer 215. The lens material layer 215 is then etched with the mask structure to form a lens structure. On the one hand, the mask structure will be naturally consumed during the etching process. On the other hand, the mask structure with the same material as the lens material layer 215 can also be used as a material layer for forming the lens structure and participate in the final structure of the lens structure, so that after the lens structure is formed, there is no need to remove the second mask layer 219 and the first mask layer 217.

[0112] The lens structure is formed by forming a mask structure through two reflows, and then etching the lens material layer 215 with the mask structure. The first part 220 and the second part 221 of the lens structure formed by the method are formed as a whole. The first part 220 and the second part 221 are more tightly combined, which is beneficial to increasing the area ratio of the lens structure and improving the alignment accuracy of the lens structure, thereby improving the process accuracy, thereby reducing the difference in the transmitted and focused light spot (Light Spot) and improving the focusing effect of the PDAF technology.

[0113] The projection of the second part 221 on the substrate 200 is located within the projection range of the first part 220 on the substrate 200, that is, the size of the second part 221 in the first direction X and the second direction Y are smaller than the size of the first part 220 in the same direction, and the second part 221 enhances the light focusing ability of the lens structure.

[0114] The first part 220 is an ellipsoid protruding from the filter layer, and the second part 221 is an ellipsoid protruding from the first part 220. The lens structure is located on two adjacent sub-areas of a pixel area. The light spot converged by the lens structure is in the shape of a long strip. The long strip of light spot is located at the junction of the two adjacent sub-areas, and the area of ​​the long strip of light spot is large. Therefore, when forming the lens structure, the size accuracy and position accuracy of the lens structure can have a larger deviation range, thereby improving the process tolerance of forming the lens structure.

[0115] In this embodiment, the first portion 220 is an ellipsoid protruding from the filter layer, and the projection of the first portion 220 on the substrate is an ellipse; the second portion 221 is an ellipsoid protruding from the first portion 220, and the projection of the second portion 221 on the substrate is an ellipse. The long axis direction of the first portion 220 is the same as the long axis direction of the second portion 221.

[0116] The first portion 220 has a first length L1, a first width W1 and a first height H1, and the second portion 221 has a second length L2, a second width W2 and a second height H2. The first length and the second length are the major axis lengths, and the first width and the second width are the minor axis lengths.

[0117] In this embodiment, the ratio of the second length L2 to the first length L1 is in the range of 0.35 to 0.75, the ratio of the second width W2 to the first width W1 is in the range of 0.15 to 0.6, and the ratio of the second height H2 to the first height H1 is in the range of 0.3 to 0.85.

[0118] Preferably, a ratio of the second length L2 to the first length L1 is 0.5; a ratio of the second width W2 to the first width W1 is 0.4; and a ratio of the second height H2 to the first height H1 is 0.6.

[0119] The ratio of the second length L2 to the first length L1 is in the range of 0.35 to 0.75, the ratio of the second width W2 to the first width W1 is in the range of 0.15 to 0.6, and the ratio of the second height H2 to the first height H1 is in the range of 0.3 to 0.85. The lens structure formed by the first part 220 and the second part 221 within the size range can better achieve global phase focusing.

[0120] The refractive index of the material of the first portion 220 is greater than 1.55; the refractive index of the material of the second portion 221 is greater than 1.55.

[0121] In this embodiment, the refractive index of the material of the first portion 220 is in the range of 1.55 to 1.65, and the refractive index of the material of the second portion 221 is in the range of 1.55 to 1.65, so that the light-gathering capability of the lens structure matches the size of the pixel region.

[0122] The material of the first part 220 includes an organic material, the organic material includes a resin, and the resin includes carbonate or polyacrylate; the material of the second part 221 includes an organic material, the organic material includes a resin, and the resin includes carbonate or polyacrylate.

[0123] In this embodiment, the first portion 220 and the second portion 221 are made of the same material.

[0124] In other embodiments, the materials of the first portion and the second portion can be different.

[0125] In each pixel unit, the arrangement direction of the lens structure on the pixel area of ​​at least one color filter layer is the same, and the arrangement direction of the lens structure includes parallel to the first direction X, or parallel to the second direction Y, including: the arrangement direction of the lens structure on the pixel area of ​​the red filter layer in each pixel unit is the same, the arrangement direction of the lens structure on the pixel area of ​​the blue filter layer in each pixel unit is the same, and the arrangement direction of the lens structure on the pixel area of ​​the green filter layer in each pixel unit is the same, or one or more of the three situations. Therefore, when the image sensor performs algorithm planning, the pixel algorithms corresponding to the same color filter layer are the same, which can optimize the processing process of the algorithm.

[0126] In this embodiment, that is, in each pixel unit, the arrangement direction of the lens structures on the first filter layer is the same, the arrangement direction of the lens structures on the second filter layer is the same, and the arrangement direction of the lens structures on the fourth filter layer is the same, or one or more of the three situations.

[0127] The image sensor formed by the method has a filter layer located on two adjacent sub-areas of a pixel area, a lens structure located on two adjacent sub-areas of a pixel area, the lens structure corresponds to the arrangement direction of the filter layer one by one, and the lens structure includes a first part and a second part 221 located on the first part 220. The lens structure with two parts improves the sensitivity of the image sensor to light, and the light spot is easily gathered at the junction of two adjacent sub-areas, rather than the central position of the four sub-areas, so that the requirements for alignment accuracy are low and the requirements for process are relatively low. That is, under the condition of lower alignment accuracy, the requirements for the resolution ability of phase information during higher phase detection autofocus can also be met, and global phase focusing can be better achieved.

[0128] In this embodiment, the arrangement direction of the lens structure on the first pixel area 201 of each pixel unit is the same, the arrangement direction of the lens structure on the second pixel area 202 of each pixel unit is the same, the arrangement direction of the lens structure on the third pixel area 203 of each pixel unit is the same, and the arrangement direction of the lens structure on the fourth pixel area 204 of each pixel unit is the same.

[0129] Please continue to refer to Fig.16 In this embodiment, the arrangement direction of the lens structures on the first pixel area 201, the second pixel area 202, the third pixel area 203 and the fourth pixel area 204 is the same. The arrangement direction of the lens structures on the first pixel area 201, the second pixel area 202, the third pixel area 203 and the fourth pixel area 204 is parallel to the first direction X.

[0130] In this embodiment, the arrangement direction of the lens structures is the long axis direction of the lens structures.

[0131] In other embodiments, the arrangement direction of the lens structures on the first pixel region, the second pixel region, the third pixel region and the fourth pixel region is parallel to the second direction Y.

[0132] In this embodiment, after the lens structure is formed, the method further includes: forming an anti-reflection layer (not shown) on the surface of the lens structure. The anti-reflection layer can enhance the transmittance of light and protect the surface of the lens structure.

[0133] The material of the antireflection layer includes inorganic oxide materials, such as silicon oxide, silicon nitride, or aluminum oxide. The thickness of the antireflection layer is determined after optical design according to the refractive index of the antireflection layer material.

[0134] In other embodiments, the antireflection layer may not be formed.

[0135] Correspondingly, an embodiment of the present invention further provides an image sensor. Please continue to refer to Figures 16 to 20 , including:

[0136] A substrate 200, the substrate 200 includes a plurality of pixel regions arranged in an array, and one pixel region includes 4 sub-regions distributed in a "field" shape;

[0137] A photosensitive structure located in the sub-region;

[0138] A plurality of filter layers located on the pixel region, one filter layer is located on two adjacent sub-regions of one pixel region, and each filter layer is separated from each other;

[0139] A plurality of lens structures located on the filter layer, the lens structures correspond to the filter layers one by one, one lens structure is located on two adjacent sub-regions of one pixel region, the lens structure includes a first part 220 and a second part 221 located on the first part 220, and the projection of the second part 221 on the substrate 200 is within the projection range of the first part 220 on the substrate 200.

[0140] In this embodiment, the first part 220 includes an ellipsoidal shape protruding from the filter layer, and the second part 221 includes an ellipsoidal shape protruding from the first part 220.

[0141] In this embodiment, the first part 220 has a first length L1, a first width W1, and a first height H1, the second part 221 has a second length L2, a second width W2, and a second height H2, the ratio range of the second length L2 to the first length L1 is 0.35 to 0.75, the ratio range of the second width to the first width is 0.15 to 0.6, and the ratio range of the second height to the first height is 0.3 to 0.85.

[0142] In this embodiment, the filter layer includes a red filter layer, a green filter layer, or a blue filter layer, and the colors of the filter layers on the 4 sub-regions of one pixel region are the same.

[0143] In this embodiment, the substrate 200 includes a plurality of pixel units P arranged in an XY array. One pixel unit P includes a first pixel region 201, a second pixel region 202, a third pixel region 203, and a fourth pixel region 204. The plurality of pixel regions arranged in an array include a plurality of first pixel regions 201, second pixel regions 202, third pixel regions 203, and fourth pixel regions 204 arranged in an array. The first pixel region 201 and the second pixel region 202 are arranged along a first direction X parallel to the surface of the substrate 200. The third pixel region 203 and the fourth pixel region 204 are arranged along the first direction X. The first pixel region 201 and the third pixel region 203 are adjacent in a second direction Y parallel to the surface of the substrate 200. The second pixel region 202 and the fourth pixel region 204 are adjacent in the second direction Y. The first direction X and the second direction Y are perpendicular. The first pixel region 201, the second pixel region 202, the third pixel region 203, and the fourth pixel region 204 are distributed in a "field" shape.

[0144] In this embodiment, a first color filter layer 210 is provided on the first pixel region 201, a second color filter layer 211 is provided on the second pixel region 202, a third color filter layer 212 is provided on the third pixel region 203, and a fourth color filter layer 213 is provided on the fourth pixel region 204. The colors of the first color filter layer 210, the second color filter layer 211, and the fourth color filter layer 213 are different from each other. The colors of the adjacent first color filter layer 210, second color filter layer 211, third color filter layer 212, and fourth color filter layer 213 are different.

[0145] In this embodiment, in each pixel unit, the arrangement directions of the lens structures on the pixel regions of at least one color of color filter layer are the same. The arrangement directions of the lens structures include parallel to the first direction or parallel to the second direction, including: the arrangement directions of the lens structures on the pixel regions of the red color filter layer in each pixel unit are the same, the arrangement directions of the lens structures on the pixel regions of the blue color filter layer in each pixel unit are the same, and the arrangement directions of the lens structures on the pixel regions of the green color filter layer in each pixel unit are the same, one or more of the three cases.

[0146] In this embodiment, the arrangement directions of the lens structures on the first pixel regions of each pixel unit are the same, the arrangement directions of the lens structures on the second pixel regions of each pixel unit are the same, the arrangement directions of the lens structures on the third pixel regions of each pixel unit are the same, and the arrangement directions of the lens structures on the fourth pixel regions of each pixel unit are the same.

[0147] In this embodiment, the arrangement directions of the lens structures on the first pixel region 201, the second pixel region 202, the third pixel region 203, and the fourth pixel region 204 are the same.

[0148] In this embodiment, the color of the first filter layer 210 includes blue, the color of the second filter layer 211 includes green, the color of the third filter layer 212 includes green, and the color of the fourth filter layer 213 includes red.

[0149] In this embodiment, the substrate 200 further includes a plurality of isolation regions, wherein the isolation regions are located between adjacent sub-regions and surround the sub-regions; and further includes an isolation structure 205 located in the isolation region and surrounding the sub-regions.

[0150] In this embodiment, it also includes: a dielectric structure located on the substrate 200, the filter layer is located on the dielectric structure; a grid structure 209 located on the dielectric structure on part of the isolation area, the grid structure 209 forms a groove spanning two adjacent sub-areas, the filter layer is located in the groove, and the grid structure 209 isolates adjacent filter layers.

[0151] In this embodiment, the photosensitive structure includes a photodiode.

[0152] In this embodiment, the first portion 220 and the second portion 221 are made of the same material.

[0153] In this embodiment, the refractive index range of the material of the first part 220 is greater than 1.55; the refractive index range of the material of the second part 221 is greater than 1.55; the material of the first part 220 includes an organic material, the organic material includes a resin, and the resin includes carbonate or polyacrylate; the material of the second part 221 includes an organic material, the organic material includes a resin, and the resin includes carbonate or polyacrylate.

[0154] In this embodiment, it also includes: an anti-reflection layer located on the surface of the lens structure.

[0155] Figure 21 to Figure 24 is a schematic structural diagram of an image sensor in another embodiment of the present invention.

[0156] Please refer to Figure 21 to Figure 24 , Fig.21 is a top view of the pixel array, Fig. 22 is a schematic diagram of a pixel unit P, Fig.23 for Fig. 22 Schematic diagram of the cross-sectional structure along the section line AA1, Fig.24 for Fig. 22 Schematic diagram of the cross-sectional structure along the section line BB1 ​​in FIG. 1 , the lens structure includes a first portion 320 and a second portion 321 located on the first portion 320 . Fig.21 and Fig.16 The difference lies in the different arrangements of the lens structures.

[0157] In each pixel unit, the arrangement direction of the lens structure on the pixel area of ​​at least one color filter layer is the same, and the arrangement direction of the lens structure includes parallel to the first direction, or parallel to the second direction, including: the arrangement direction of the lens structure on the pixel area of ​​the red filter layer in each pixel unit is the same, the arrangement direction of the lens structure on the pixel area of ​​the blue filter layer in each pixel unit is the same, and the arrangement direction of the lens structure on the pixel area of ​​the green filter layer in each pixel unit is the same, and one or more of the three situations.

[0158] In this embodiment, that is, in each pixel unit, the arrangement direction of the lens structures on the first filter layer is the same, the arrangement direction of the lens structures on the second filter layer is the same, and the arrangement direction of the lens structures on the fourth filter layer is the same, or one or more of the three situations.

[0159] In this embodiment, the arrangement directions of the lens structures on the first pixel area 201 and the second pixel area 202 arranged along the first direction X are different, the arrangement directions of the lens structures on the first pixel area 201 and the third pixel area 203 arranged along the second direction Y are the same, and the arrangement directions of the lens structures on the second pixel area 202 and the fourth pixel area 204 arranged along the second direction Y are the same.

[0160] In this embodiment, the arrangement direction of the lens structure on the first pixel area 201 is parallel to the first direction X, the arrangement direction of the lens structure on the second pixel area 202 is parallel to the second direction Y, the arrangement direction of the lens structure on the third pixel area 203 is parallel to the first direction X, and the arrangement direction of the lens structure on the fourth pixel area 204 is parallel to the second direction Y.

[0161] In other embodiments, the arrangement direction of the lens structure on the first pixel area is parallel to the second direction Y, the arrangement direction of the lens structure on the second pixel area is parallel to the first direction X, the arrangement direction of the lens structure on the third pixel area is parallel to the second direction Y, and the arrangement direction of the lens structure on the fourth pixel area is parallel to the first direction X.

[0162] The first portion 320 has a first length L1, a first width W1 and a first height H1, and the second portion 321 has a second length L2, a second width W2 and a second height H2. For a description of the relationship between the first length L1, the first width W1 and the first height H1, the second length L2, the second width W2 and the second height H2, please refer to Figures 16 to 20 Description in .

[0163] In this embodiment, it further comprises: an anti-reflection layer (not shown) located on the surface of the lens structure. The anti-reflection layer can enhance the transmittance of light and protect the surface of the lens structure.

[0164] The material of the anti-reflection layer includes an inorganic oxide material, and the inorganic oxide material includes silicon oxide, silicon nitride or aluminum oxide, etc. The thickness of the anti-reflection layer is determined after optical design based on the refractive index of the anti-reflection layer material.

[0165] In other embodiments, the anti-reflection layer may not be formed on the surface of the lens structure.

[0166] Figure 25 to Figure 28 is a schematic structural diagram of an image sensor in another embodiment of the present invention.

[0167] Please refer to Figure 25 to Figure 28 , Fig.25 is a top view of the pixel array, Fig.26 is a schematic diagram of a pixel unit P, Fig. 27 for Fig.26 Schematic diagram of the cross-sectional structure along the section line AA1, Fig.28 for Fig.26 Schematic diagram of the cross-sectional structure along the section line BB1 ​​in FIG. 1 , the lens structure includes a first portion 420 and a second portion 421 located on the first portion 420 . Fig.25 and Fig.16 The difference lies in the different arrangements of the lens structures.

[0168] In each pixel unit, the arrangement direction of the lens structure on the pixel area of ​​at least one color filter layer is the same, and the arrangement direction of the lens structure includes parallel to the first direction, or parallel to the second direction, including: the arrangement direction of the lens structure on the pixel area of ​​the red filter layer in each pixel unit is the same, the arrangement direction of the lens structure on the pixel area of ​​the blue filter layer in each pixel unit is the same, and the arrangement direction of the lens structure on the pixel area of ​​the green filter layer in each pixel unit is the same, and one or more of the three situations.

[0169] In this embodiment, that is, in each pixel unit, the arrangement direction of the lens structures on the first filter layer is the same, the arrangement direction of the lens structures on the second filter layer is the same, and the arrangement direction of the lens structures on the fourth filter layer is the same, or one or more of the three situations.

[0170] In this embodiment, the arrangement direction of the lens structure on the first pixel area 201 of each pixel unit is the same, the arrangement direction of the lens structure on the second pixel area 202 of each pixel unit is the same, the arrangement direction of the lens structure on the third pixel area 203 of each pixel unit is the same, and the arrangement direction of the lens structure on the fourth pixel area 204 of each pixel unit is the same.

[0171] In this embodiment, the arrangement directions of the lens structures on the first pixel area 201, the second pixel area 202, the third pixel area 203 and the fourth pixel area 204 that are adjacent to each other are different. The lens arrangement direction on the first pixel area 201 is the same as the lens arrangement direction on the fourth pixel area 204, and the lens arrangement direction on the second pixel area 202 is the same as the lens arrangement direction on the third pixel area 203.

[0172] In this embodiment, the lens arrangement direction on the first pixel area 201 and the lens arrangement direction on the fourth pixel area 204 are parallel to the second direction Y, and the lens arrangement direction on the second pixel area 202 and the lens arrangement direction on the third pixel area 203 are parallel to the first direction X.

[0173] In other embodiments, the lens arrangement direction on the first pixel area and the lens arrangement direction on the fourth pixel area are parallel to the first direction X, and the lens arrangement direction on the second pixel area and the lens arrangement direction on the third pixel area are parallel to the second direction Y.

[0174] The first portion 420 has a first length L1, a first width W1 and a first height H1, and the second portion 421 has a second length L2, a second width W2 and a second height H2. For a description of the relationship between the first length L1, the first width W1 and the first height H1, the second length L2, the second width W2 and the second height H2, please refer to Figures 16 to 20 Description in .

[0175] In this embodiment, it further comprises: an anti-reflection layer (not shown) located on the surface of the lens structure. The anti-reflection layer can enhance the transmittance of light and protect the surface of the lens structure.

[0176] The material of the anti-reflection layer includes an inorganic oxide material, and the inorganic oxide material includes silicon oxide, silicon nitride or aluminum oxide, etc. The thickness of the anti-reflection layer is determined after optical design based on the refractive index of the anti-reflection layer material.

[0177] In other embodiments, the anti-reflection layer may not be formed on the surface of the lens structure.

[0178] Figure 29 to Figure 32is a schematic structural diagram of an image sensor in another embodiment of the present invention.

[0179] Please refer to Figure 29 to Figure 32 , Fig.29 is a top view of the pixel array, Fig.30 is a schematic diagram of a pixel unit P, Fig.31 for Fig.30 Schematic diagram of the cross-sectional structure along the section line AA1, Fig.32 for Fig.30 Schematic diagram of the cross-sectional structure along the section line BB1 ​​in FIG. 1 , the lens structure includes a first portion 520 and a second portion 521 located on the first portion 520 . Fig.29 and Fig.16 The difference lies in the different arrangements of the lens structures.

[0180] In each pixel unit, the arrangement direction of the lens structure on the pixel area of ​​at least one color filter layer is the same, and the arrangement direction of the lens structure includes parallel to the first direction, or parallel to the second direction, including: the arrangement direction of the lens structure on the pixel area of ​​the red filter layer in each pixel unit is the same, the arrangement direction of the lens structure on the pixel area of ​​the blue filter layer in each pixel unit is the same, and the arrangement direction of the lens structure on the pixel area of ​​the green filter layer in each pixel unit is the same, and one or more of the three situations.

[0181] In this embodiment, that is, in each pixel unit, the arrangement direction of the lens structures on the first filter layer is the same, the arrangement direction of the lens structures on the second filter layer is the same, and the arrangement direction of the lens structures on the fourth filter layer is the same, or one or more of the three situations.

[0182] In this embodiment, the arrangement direction of the lens structure on the first pixel area 201 of each pixel unit is the same, the arrangement direction of the lens structure on the second pixel area 202 of each pixel unit is the same, the arrangement direction of the lens structure on the third pixel area 203 of each pixel unit is the same, and the arrangement direction of the lens structure on the fourth pixel area 204 of each pixel unit is the same.

[0183] In this embodiment, the lens arrangement direction on the second pixel area 202, the third pixel area 203, and the fourth pixel area 204 is the same, and the lens arrangement direction on the first pixel area 201 is different from the lens arrangement direction on the second pixel area 202, the third pixel area 203, and the fourth pixel area 204.

[0184] In this embodiment, the lenses on the second pixel area 202 , the third pixel area 203 , and the fourth pixel area 204 are arranged in a direction parallel to the first direction X, and the lenses on the first pixel area 201 are arranged in a direction parallel to the second direction Y.

[0185] In other embodiments, the lens arrangement direction on the second pixel area, the third pixel area, and the fourth pixel area is parallel to the second direction Y, and the lens arrangement direction on the first pixel area is parallel to the first direction X.

[0186] The first portion 520 has a first length L1, a first width W1 and a first height H1, and the second portion 521 has a second length L2, a second width W2 and a second height H2. For a description of the relationship between the first length L1, the first width W1 and the first height H1, the second length L2, the second width W2 and the second height H2, please refer to Figures 16 to 20 Description in .

[0187] In this embodiment, it further comprises: an anti-reflection layer (not shown) located on the surface of the lens structure. The anti-reflection layer can enhance the transmittance of light and protect the surface of the lens structure.

[0188] The material of the anti-reflection layer includes an inorganic oxide material, and the inorganic oxide material includes silicon oxide, silicon nitride or aluminum oxide, etc. The thickness of the anti-reflection layer is determined after optical design based on the refractive index of the anti-reflection layer material.

[0189] In other embodiments, the anti-reflection layer may not be formed on the surface of the lens structure.

[0190] Fig.33 is a schematic structural diagram of an image sensor in another embodiment of the present invention.

[0191] Please refer to Fig.33 , Fig.33 is a top view of the pixel array, Fig.33 and Fig.16 The difference lies in the different arrangements of the lens structures.

[0192] In this embodiment, the arrangement directions of the lens structures on the first pixel area 201 , the second pixel area 202 , the third pixel area 203 and the fourth pixel area 204 in one pixel unit are the same, and the arrangement directions of the lens structures on two adjacent pixel units are different.

[0193] In this embodiment, the arrangement direction of the lens structures on the first pixel area 201, the second pixel area 202, the third pixel area 203 and the fourth pixel area 204 in one pixel unit is parallel to the first direction X, and in another pixel unit adjacent to the first direction X and the second direction Y, the arrangement direction of the lens structures on the first pixel area 201, the second pixel area 202, the third pixel area 203 and the fourth pixel area 204 in the other pixel unit is parallel to the second direction Y.

[0194] Fig.34is a schematic structural diagram of an image sensor in another embodiment of the present invention.

[0195] Please refer to Fig.34 , Fig.34 is a top view of the pixel array, Fig.34 and Fig.16 The difference lies in the different arrangements of the lens structures.

[0196] In this embodiment, the arrangement directions of the lens structures on the first pixel area 201, the second pixel area 202, the third pixel area 203 and the fourth pixel area 204 in one pixel unit are the same, the arrangement directions of the lens structures on two adjacent pixel units arranged along the first direction X are different, and the arrangement directions of the lens structures on two adjacent pixel units arranged along the second direction Y are the same.

[0197] In this embodiment, the arrangement direction of the lens structures on the first pixel area 201, the second pixel area 202, the third pixel area 203 and the fourth pixel area 204 in a pixel unit is parallel to the first direction X, the arrangement direction of the lens structures on adjacent pixel units arranged along the first direction X is parallel to the second direction Y, and the arrangement direction of the lens structures on adjacent pixel units arranged along the second direction Y is parallel to the first direction X.

[0198] Fig.35 is a schematic structural diagram of an image sensor in another embodiment of the present invention.

[0199] Please refer to Fig.35 , Fig.35 is a top view of a pixel array, which includes a plurality of pixel regions distributed in an XY array, and schematically shows a first column of pixel regions 601 , a second column of pixel regions 602 , a third column of pixel regions 603 , and a fourth column of pixel regions 604 .

[0200] In this embodiment, the colors of the filter layers on the pixel areas in a row or a column are the same, and the colors of the filter layers on the pixel areas in two adjacent rows or columns are different from each other; the arrangement directions of the lens structures on the two adjacent pixel areas in the first row or the first column are different, and the arrangement direction of the lens structures on the pixel areas in the second row or the second column adjacent to the first row or the first column is the same.

[0201] In this embodiment, the color of the filter layers on the pixel regions in a column is the same: the color of the filter layer on the first column of pixel regions 601 is blue, the color of the filter layer on the second column of pixel regions 602 is green, the color of the filter layer on the third column of pixel regions 603 is red, and the color of the filter layer on the fourth column of pixel regions 604 is blue.

[0202] In this embodiment, the arrangement directions of the lens structures on two adjacent pixel areas 601 in the first column of pixel areas 601 are different, and the arrangement direction of the lens structures on the second column of pixel areas 602 adjacent to the first column of pixel areas 601 is the same, which is parallel to the first direction X; the arrangement directions of the lens structures on two adjacent pixel areas 603 in the third column of pixel areas 603 are different, and the arrangement direction of the lens structures on the fourth column of pixel areas 604 adjacent to the third column of pixel areas 603 is the same, which is parallel to the first direction X.

[0203] In this embodiment, it further comprises: an anti-reflection layer (not shown) located on the surface of the lens structure. The anti-reflection layer can enhance the transmittance of light and protect the surface of the lens structure.

[0204] The material of the anti-reflection layer includes an inorganic oxide material, and the inorganic oxide material includes silicon oxide, silicon nitride or aluminum oxide, etc. The thickness of the anti-reflection layer is determined after optical design based on the refractive index of the anti-reflection layer material.

[0205] In other embodiments, the anti-reflection layer may not be formed on the surface of the lens structure.

[0206] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. An image sensor, characterized in that: Comprising: A substrate, the substrate comprising a plurality of pixel regions arranged in an array, one pixel region comprising 4 sub-regions distributed in a "field" shape; A plurality of filter layers located on the pixel regions, one filter layer being located on two adjacent sub-regions of one pixel region, and the filter layers being discrete from each other; A plurality of lens structures located on the filter layers, the lens structures corresponding to the filter layers one by one, one lens structure being located on two adjacent sub-regions of one pixel region, the lens structure comprising a first part and a second part located on the first part, and the projection of the second part on the substrate being within the projection range of the first part on the substrate.

2. The image sensor according to claim 1, wherein: The first part comprises an ellipsoidal shape protruding from the filter layer, and the second part comprises an ellipsoidal shape protruding from the first part.

3. The image sensor according to claim 2, wherein: The first part has a first length, a first width and a first height, the second part has a second length, a second width and a second height, the ratio range of the second length to the first length is 0.35 to 0.75, the ratio range of the second width to the first width is 0.15 to 0.6, and the ratio range of the second height to the first height is 0.3 to 0.

85.

4. The image sensor according to claim 1, wherein: The filter layer comprises a red filter layer, a green filter layer or a blue filter layer, and the filter layers on the 4 sub-regions of one pixel region have the same color.

5. The image sensor according to claim 4, wherein: The substrate comprises a plurality of pixel units arranged in an array, one pixel unit comprising a first pixel region, a second pixel region, a third pixel region and a fourth pixel region, the first pixel region and the second pixel region being arranged along a first direction parallel to the surface of the substrate, the third pixel region and the fourth pixel region being arranged along the first direction, the first pixel region and the third pixel region being adjacent in a second direction parallel to the surface of the substrate, the second pixel region and the fourth pixel region being adjacent in the second direction, the first direction and the second direction being perpendicular, the first pixel region comprising 4 first sub-regions distributed in a "field" shape, the second pixel region comprising 4 second sub-regions distributed in a "field" shape, the third pixel region comprising 4 third sub-regions distributed in a "field" shape, and the fourth pixel region comprising 4 fourth sub-regions distributed in a "field" shape; a first filter layer is provided on the first pixel region, a second filter layer is provided on the second pixel region, a third filter layer is provided on the third pixel region, and a fourth filter layer is provided on the fourth pixel region, the colors of the first filter layer, the second filter layer and the fourth filter layer are different from each other, and the colors of the adjacent first filter layer, second filter layer, third filter layer and fourth filter layer are different.

6. The image sensor according to claim 5, characterized in that In each pixel unit, the arrangement directions of the lens structures on the pixel regions of at least one color of the filter layer are the same, and the arrangement directions of the lens structures include parallel to the first direction or parallel to the second direction, including: the arrangement directions of the lens structures on the pixel regions of the red filter layer in each pixel unit are the same, the arrangement directions of the lens structures on the pixel regions of the blue filter layer in each pixel unit are the same, and the arrangement directions of the lens structures on the pixel regions of the green filter layer in each pixel unit are the same, one or more of the three cases.

7. The image sensor according to claim 6, wherein: The arrangement direction of the lens structure on the first pixel area of ​​each pixel unit is the same, the arrangement direction of the lens structure on the second pixel area of ​​each pixel unit is the same, the arrangement direction of the lens structure on the third pixel area of ​​each pixel unit is the same, and the arrangement direction of the lens structure on the fourth pixel area of ​​each pixel unit is the same.

8. The image sensor according to claim 7, wherein: The lens structures on the first pixel region, the second pixel region, the third pixel region and the fourth pixel region are arranged in the same direction.

9. The image sensor according to claim 7, wherein: The arrangement directions of the lens structures on the first pixel area, the second pixel area, the third pixel area and the fourth pixel area that are adjacent to each other are different. The lens arrangement direction on the first pixel area is the same as the lens arrangement direction on the fourth pixel area, and the lens arrangement direction on the second pixel area is the same as the lens arrangement direction on the third pixel area; or, the lens arrangement directions on the second pixel area, the third pixel area and the fourth pixel area are the same, and the lens arrangement direction on the first pixel area is different from the lens arrangement directions on the second pixel area, the third pixel area and the fourth pixel area.

10. The image sensor according to claim 6, wherein: The arrangement directions of the lens structures on the first pixel area and the second pixel area arranged along the first direction are different, the arrangement directions of the lens structures on the first pixel area and the third pixel area arranged along the second direction are the same, and the arrangement directions of the lens structures on the second pixel area and the fourth pixel area arranged along the second direction are the same.

11. The image sensor according to claim 5, wherein: The arrangement directions of the lens structures on the first pixel region, the second pixel region, the third pixel region and the fourth pixel region in one pixel unit are the same, and the arrangement directions of the lens structures on two adjacent pixel units are different.

12. The image sensor according to claim 5, wherein: The arrangement directions of the lens structures on the first pixel area, the second pixel area, the third pixel area and the fourth pixel area within a pixel unit are the same, the arrangement directions of the lens structures on two adjacent pixel units arranged along the first direction are different, and the arrangement directions of the lens structures on two adjacent pixel units arranged along the second direction are the same.

13. The image sensor according to claim 5, wherein: The color of the first filter layer includes blue, the color of the second filter layer includes green, the color of the third filter layer includes green, and the color of the fourth filter layer includes red.

14. The image sensor according to claim 4, wherein: The colors of the filter layers on the pixel areas in one row or one column are the same, and the colors of the filter layers on the pixel areas in two adjacent rows or columns are different from each other; the arrangement directions of the lens structures on the two adjacent pixel areas in the first row or the first column are different, and the arrangement directions of the lens structures on the pixel areas in the second row or the second column adjacent to the first row or the first column are the same.

15. The image sensor according to claim 1, wherein: The substrate further comprises a plurality of isolation regions, wherein the isolation regions are located between adjacent sub-regions and surround the sub-regions; and further comprises an isolation structure located in the isolation region and surrounding the sub-regions.

16. The image sensor according to claim 15, wherein: Also includes: A dielectric structure is located on the substrate, and the filter layer is located on the dielectric structure; a grid structure is located on the dielectric structure on part of the isolation area, and the grid structure forms a groove spanning two adjacent sub-areas, and the filter layer is located in the groove, and the grid structure isolates adjacent filter layers.

17. The image sensor according to claim 1, wherein: Also includes: A photosensitive structure is located in the sub-area; the photosensitive structure includes a photodiode.

18. The image sensor according to claim 1, wherein: The materials of the first part and the second part are the same.

19. The image sensor according to claim 1, wherein: The refractive index range of the material of the first part is greater than 1.55; the refractive index range of the material of the second part is greater than 1.55; the material of the first part includes an organic material, the organic material includes a resin, and the resin includes a carbonate or a polyacrylate; the material of the second part includes an organic material, the organic material includes a resin, and the resin includes a carbonate or a polyacrylate.

20. The image sensor according to claim 1, wherein: It further includes: An antireflection layer located on the surface of the lens structure.

21. A method of forming an image sensor as claimed in any one of claims 1 to 20, characterized in that: It includes: Providing a substrate, the substrate includes a plurality of pixel regions arranged in an array, and one pixel region includes 4 sub-regions distributed in a "field" shape; Forming a plurality of filter layers on the pixel region, one filter layer is located on two adjacent sub-regions of one pixel region, and each filter layer is discrete from each other; Forming a plurality of lens structures on the filter layer, the lens structures correspond to the filter layers one by one, one lens structure is located on two adjacent sub-regions of one pixel region, the lens structure includes a first part and a second part located on the first part, and the projection of the second part on the substrate is within the projection range of the first part on the substrate.

22. The method for forming an image sensor according to claim 21, wherein: The substrate further includes a plurality of isolation regions, the isolation regions are located between adjacent sub-regions, and the isolation regions surround the sub-regions; it further includes: forming an isolation structure in the isolation regions, the isolation structure surrounds the sub-regions; forming a photosensitive structure in the sub-regions.

23. The method for forming an image sensor according to claim 22, wherein: Before forming the filter layer on the pixel region, it further includes: forming a dielectric structure on the substrate, the filter layer is located on the dielectric structure; forming a grid structure on the dielectric structure in part of the isolation regions, the grid structure encloses a groove spanning two adjacent sub-regions; the method for forming the filter layer includes: filling a filter material layer in the groove; planarizing the filter material layer to form the filter layer in the groove, and the grid structure isolates adjacent filter layers.

24. The method for forming an image sensor according to claim 23, wherein: The method for forming the lens structure includes: forming a lens material layer on the grid structure and the filter layer; forming a first mask layer on the lens material layer, the first mask layer is an ellipsoidal shape protruding from the filter layer, and the first mask layer is located on two adjacent sub-regions of one pixel region; forming a second mask layer on the first mask layer, the second mask layer is an ellipsoidal shape protruding from the first mask layer, and the projection of the second mask layer on the substrate is within the projection range of the first mask layer on the substrate; etching the lens material layer with the second mask layer and the first mask layer as masks to form a lens structure located on the filter layer, the lens structure includes a first part and a second part located on the first part, and the projection of the second part on the substrate is within the projection range of the first part on the substrate.

25. The method for forming an image sensor according to claim 24, wherein: The method for forming the first mask layer includes: forming an initial first mask layer on the lens material layer, the initial first mask layer is located on two adjacent sub-regions of one pixel region; performing a reflow process on the initial first mask layer to form the first mask layer on the lens material layer.

26. The method for forming an image sensor according to claim 24, wherein: The method for forming the second mask layer includes: forming an initial second mask layer on the first mask layer, the projection of the initial second mask layer on the substrate is located within the projection range of the first mask layer on the substrate; reflowing the initial second mask layer to form the second mask layer on the first mask layer.

27. The method for forming an image sensor according to claim 24, wherein: The material of the first mask layer and the material of the second mask layer are the same as the material of the lens structure; the material of the first mask layer and the second mask layer include organic materials, the organic materials include resins, and the resins include carbonate or polyacrylate.

28. The method for forming an image sensor according to claim 21, wherein: Also includes: An anti-reflection layer is formed on the surface of the lens structure.

Images