Image sensor and manufacturing method thereof

Abstract

This invention discloses an image sensor and its fabrication method, belonging to the field of semiconductor technology. The image sensor includes: a substrate; a bottom isolation layer disposed in the substrate and bonded to a surface of the substrate; multiple material layers disposed on the bottom isolation layer, with adjacent material layers overlapping in the growth direction of the material layers; a deep trench isolation structure disposed in the material layers, the deep trench isolation structure isolating the material layers into various types of photoelectric sensing areas; a grid disposed on the deep trench isolation structure; and a color filter disposed on the photoelectric sensing areas. The image sensor and its fabrication method provided by this invention improve the performance of the image sensor and simplify its manufacturing process.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to an image sensor and a manufacturing method thereof. Background Art

[0002] Image sensors are devices that convert light signals into electrical signals and are widely used in photography, security systems, smart phones, fax machines, scanners, medical electronics and other fields.

[0003] The photoelectric sensing area of ​​the image sensor can sense light signals and convert them into electrical signals. However, when forming the photoelectric sensing area, high-energy ion injection is required, which damages the substrate. In addition, the photoelectric sensing area formed by the damaged substrate is prone to generate electron holes, and the electrons flow to the photoelectric sensing area or other structural layers through the surrounding damaged area. Therefore, crosstalk occurs between adjacent photoelectric sensing areas and between the photoelectric sensing area and other structural layers. In addition, for some image sensors, electrical signals of different intensities need to be formed. At this time, the intensity of the light signal in each photoelectric sensing area needs to be adjusted to meet the image sensor's requirements for electrical signal intensity, which has a greater impact on the manufacture of the image sensor. Summary of the invention

[0004] The object of the present invention is to provide an image sensor and a method for manufacturing the same, which can improve the performance of the image sensor, reduce leakage current, reduce signal crosstalk, and form electrical signals with different intensities.

[0005] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0006] The present invention provides an image sensor, comprising:

[0007] substrate;

[0008] A bottom isolation layer is disposed in the substrate, and the bottom isolation layer is bonded to a surface of the substrate;

[0009] A plurality of material layers are arranged on the bottom isolation layer, and two adjacent material layers are arranged to overlap in the growth direction of the material layers;

[0010] A deep trench isolation structure is disposed in the material layer, wherein the deep trench isolation structure isolates the material layer into multiple types of photoelectric sensing regions;

[0011] a grid disposed on the deep trench isolation structure; and

[0012] A color filter is arranged on the photoelectric sensing area.

[0013] In an embodiment of the present invention, the multi-layer material layer includes a first material layer, the first material layer is disposed on the bottom isolation layer, and a first groove is disposed in the first material layer, and the first groove exposes the bottom isolation layer.

[0014] In one embodiment of the present invention, the multi-layer material layer comprises:

[0015] a second material layer, disposed on the first material layer, and the second material layer covers the first material layer and the first groove, a second groove is formed in the second material layer, and the second groove is located on the first groove; and

[0016] The third material layer is disposed on the second material layer, and the third material layer covers the second material layer.

[0017] In one embodiment of the present invention, the multiple types of photoelectric sensing regions include a first type of photoelectric sensing region, the first type of photoelectric sensing region includes the first material layer, the second material layer and the third material layer, and the second material layer is located on the first material layer, and the third material layer is located on the second material layer.

[0018] In one embodiment of the present invention, the multiple types of photoelectric sensing regions include a second type of photoelectric sensing region, the second type of photoelectric sensing region includes the first material layer, the second material layer and the third material layer, and part of the second material layer is located on the first material layer, part of the second material layer is located in the first groove, the third material layer is located on the second material layer, and the third material layer fills the second groove.

[0019] In one embodiment of the present invention, the multiple types of photoelectric sensing regions include a third type of photoelectric sensing region, and the third type of photoelectric sensing region includes the second material layer and the third material layer, the second material layer is located on the bottom isolation layer, and the third material layer is located on the second material layer.

[0020] In one embodiment of the present invention, the image sensor includes a top isolation layer, and the top isolation layer is located on the surface of the photoelectric sensing area.

[0021] In one embodiment of the present invention, the grid includes a high dielectric constant material layer, an aluminum metal layer and a titanium nitride layer, the high dielectric constant material layer is located on the deep trench isolation structure, the aluminum metal layer is located on the high dielectric constant material layer, and the titanium nitride layer is located on the aluminum metal layer.

[0022] The present invention also provides a method for manufacturing an image sensor, comprising the following steps:

[0023] providing a substrate,

[0024] forming a bottom isolation layer in the substrate, wherein the bottom isolation layer is bonded to a surface of the substrate;

[0025] forming a plurality of material layers on the bottom isolation layer, wherein two adjacent material layers are overlapped in the growth direction of the material layers;

[0026] forming a deep trench isolation structure in the material layer, wherein the deep trench isolation structure isolates the material layer into multiple types of photoelectric sensing regions;

[0027] forming a grid on the deep trench isolation structure; and

[0028] A color filter is formed on the photoelectric sensing area.

[0029] In one embodiment of the present invention, forming multiple types of photoelectric sensing regions includes the following steps:

[0030] forming a first material layer on the bottom isolation layer, and forming a first groove in the first material layer;

[0031] forming a second material layer on the first material layer, wherein the second material layer covers the first material layer, and forming a second groove in the second material layer;

[0032] forming a third material layer on the second material layer;

[0033] forming a top isolation layer and a hard mask layer on the third material layer;

[0034] patterning the hard mask layer, and etching the top isolation layer, the third material layer, the second material layer, the first material layer, and a portion of the bottom isolation layer not covered by the hard mask layer to form a deep trench; and

[0035] A dielectric is deposited in the deep trench to form a deep trench isolation structure, and the deep trench isolation structure isolates the first material layer, the second material layer and the third material layer into multiple types of photoelectric sensing regions.

[0036] In summary, the image sensor and its manufacturing method provided by the present invention have the unexpected effect of using multiple layers of material layers to form a photoelectric sensing area, which can increase the electron concentration in the photoelectric sensing area, thereby increasing the intensity of the generated electrical signal. At the same time, the material layer is formed in a layer-by-layer growth manner, so that it is not easy to generate electron holes in the formed photoelectric sensing area, thereby improving the crosstalk between adjacent photoelectric sensing areas and between the photoelectric sensing area and other structural layers. In addition, in the present application, by forming different types of photoelectric sensing areas, electrical signals of different intensities can be generated for the same light signal, thereby meeting the needs of some image sensors for the formation of electrical signals of different intensities. In addition, the grid formed in the present application includes a high dielectric constant material layer, an aluminum metal layer and a titanium nitride layer, which can not only better isolate adjacent photoelectric sensing areas, but also play a better light shielding role, and can also reduce the generation of dark current.

[0037] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0039] Figure 1 FIG. 1 is a schematic diagram of a structure for forming a shallow trench isolation structure in an embodiment.

[0040] Figure 2 FIG. 4 is a schematic diagram of a structure for forming a bottom isolation layer in an embodiment.

[0041] Figure 3 FIG. 1 is a schematic diagram of a structure in which a portion of a substrate is removed in one embodiment.

[0042] Figure 4 FIG. 4 is a schematic diagram of a structure for forming a first material layer in an embodiment.

[0043] Figure 5 FIG. 4 is a schematic diagram of a structure for forming a photoresist layer in an embodiment.

[0044] Figure 6 FIG. 4 is a schematic diagram of a structure for forming a first groove in an embodiment.

[0045] Figure 7 FIG. 4 is a schematic diagram of a structure for forming a second material layer in an embodiment.

[0046] Figure 8 FIG. 4 is a schematic diagram of a structure for forming a third material layer in an embodiment.

[0047] Fig. 9 FIG. 4 is a schematic diagram of a structure for planarizing a third material layer in an embodiment.

[0048] Fig.10 FIG. 4 is a schematic diagram of a structure for forming a top isolation layer and a hard mask layer in one embodiment.

[0049] Fig.11 FIG. 4 is a schematic diagram of a structure for forming a patterned hard mask layer in one embodiment.

[0050] Fig.12 FIG. 4 is a schematic diagram of a structure for forming a deep trench in an embodiment.

[0051] Fig.13 FIG. 4 is a schematic diagram of a structure for forming a deep trench isolation structure in an embodiment.

[0052] Fig.14 FIG. 1 is a schematic diagram of a structure for forming a high dielectric constant material layer, an aluminum metal layer and a titanium nitride layer in one embodiment.

[0053] Fig.15 FIG. 1 is a schematic diagram of a structure for forming a grid in an embodiment.

[0054] Fig.16 FIG. 4 is a schematic diagram of a structure for forming a color filter in an embodiment.

[0055] Description of labels:

[0056] 100, substrate; 101, shallow trench isolation structure; 102, etch stop layer; 103, metal interconnect layer; 104, bottom isolation layer; 105, first material layer; 1051, first groove; 106, photoresist layer; 1061, first opening; 107, second material layer; 1071, second groove; 108, third material layer; 109, top isolation layer; 110, hard mask layer; 1101, second opening; 111, deep trench; 112, deep trench isolation structure; 113, grid; 1131, high dielectric constant material layer; 1132, aluminum metal layer; 1133, titanium nitride layer; 114, color filter. DETAILED DESCRIPTION

[0057] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0058] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0059] In the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0060] The image sensor includes a pixel array and a logic control area. The pixel array is provided with a plurality of photoelectric sensing areas arranged in an array, each photoelectric sensing area forms a pixel unit, and a plurality of photoelectric sensing areas form a pixel array. The scene is focused onto the pixel array of the image sensor through an imaging lens, and the photoelectric sensing area can convert the light signal on its surface into an electrical signal. The logic control area includes a plurality of logic control devices, and the plurality of logic control devices can control the photoelectric sensing area to perform photoelectric conversion to form an electrical signal, and quantize the electrical signal through analog-to-digital conversion, and read out the converted digital signal.

[0061] See also Figures 1 to 15 As shown, in one embodiment of the present invention, the image sensor includes a substrate 100, and the substrate 100 has a first surface and a second surface opposite to each other. In the substrate 100, and located on a side close to the first surface, a bottom isolation layer 104 is provided. On the first surface of the substrate 100, a multi-layer material layer is provided. In the multi-layer material layer, a deep trench isolation structure 112 is provided, and the deep trench isolation structure 112 isolates the multi-layer material layer into a plurality of photoelectric sensing regions. On the deep trench isolation structure 112, a grid 113 is provided. On the photoelectric sensing region, a color filter 114 is provided. In the substrate 100, and located on a side close to the second surface, a plurality of shallow trench isolation structures 101 are provided. On the second surface of the substrate 100, an etching stop layer 102 and a metal interconnection layer 103 are provided. Among them, the etching stop layer 102 is located on the second surface of the substrate 100, and the metal interconnection layer 103 is located on the etching stop layer 102.

[0062] It should be noted that the first surface and the second surface are two surfaces used to distinguish the substrate, wherein the first surface is a side of the image sensor that receives incident light, and the second surface is arranged relative to the first surface.

[0063] For details, please refer to Figure 1 As shown, in one embodiment of the present invention, the substrate 100 may be any applicable semiconductor material, such as silicon, silicon carbide (SiC), gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), germanium silicon (GeSi), etc., and may also include a stacked structure composed of these semiconductors, or silicon on insulator, stacked silicon on insulator, stacked silicon germanium on insulator, silicon germanium on insulator, and germanium on insulator. In this embodiment, the substrate 100 is, for example, a silicon substrate. In the present application, the thickness of the substrate 100 is, for example, 3um.

[0064] See also Figure 1 As shown, in one embodiment of the present invention, a shallow trench isolation structure 101 is provided in the substrate 100. The shallow trench isolation structure 101 is located on one side of the substrate 100 and on the side close to the second surface. In this embodiment, the shallow trench isolation structure 101 extends from the second surface of the substrate 100 to the substrate 100. Specifically, a photoresist layer (not shown in the figure) can be formed on the second surface of the substrate 100, and a patterned photoresist layer (not shown in the figure) can be formed by processes such as exposure and development, and the patterned photoresist layer can define the position of the shallow trench. Then, the patterned photoresist layer is used as a mask, and a part of the substrate 100 located under the patterned photoresist layer is quantitatively removed by etching methods such as dry etching, wet etching, or a combination of dry etching and wet etching to obtain a shallow trench. After the shallow trench is formed, an isolation medium is deposited in the shallow trench, and the isolation medium is, for example, an insulating material such as silicon oxide. The top of the isolation dielectric is polished flat by a planarization process such as chemical mechanical polishing (CMP), thereby forming a plurality of shallow trench isolation structures 101 .

[0065] See also Figure 1 As shown, in one embodiment of the present invention, after forming the shallow trench isolation structure 101, an etching stop layer 102 is formed on the second surface of the substrate 100, and a metal interconnect layer 103 is formed on the etching stop layer 102. Specifically, a chemical vapor deposition (CVD) process can be used to deposit silicon oxide (SiO 2) or silicon carbonitride (SiCN) as the etching stop layer 102. Then, a silicon oxide medium is deposited on the etching stop layer 102, and a plurality of openings are formed in the silicon oxide medium, and a conductive material is deposited in the openings to form a metal interconnection layer 103. Through the metal interconnection layer 103, the electrical signal formed in the photoelectric sensing area can be output.

[0066] See also Figure 1 to Figure 2 As shown, in one embodiment of the present invention, after forming the metal interconnection layer 103, ions are implanted into the substrate 100 on the first surface of the substrate 100 to form a bottom isolation layer 104. Specifically, boron ions can be implanted into the substrate 100 to form the bottom isolation layer 104. In the present application, the bottom isolation layer 104 is located in the substrate 100, and one side of the bottom isolation layer 104 is in contact with the shallow trench isolation structure 101. After the bottom isolation layer 104 is formed, the substrate 100 on the bottom isolation layer 104 is etched away, so that the other side of the bottom isolation layer 104 is in contact with the surface of the etched substrate 100. Figure 3 As shown, after the bottom isolation layer 104 is formed, the substrate 100 on the bottom isolation layer 104 may be removed by a planarization process such as chemical mechanical polishing.

[0067] See also Figures 4 to 13 As shown, in one embodiment of the present invention, after forming a bottom isolation layer 104 and removing the substrate 100 on the bottom isolation layer 104, a multi-layer material layer is formed on the bottom isolation layer 104, and a deep trench isolation structure 112 is formed in the material layer, and the deep trench isolation structure 112 isolates the multi-layer material layer into a plurality of photoelectric sensing regions. In the present application, three material layers are provided on the bottom isolation layer 104. In other embodiments, four, five or more material layers are provided on the bottom isolation layer 104. Among them, the material layer is formed using a compound of Group VA elements and silicon. Group VA elements include nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi) and molybdenum (Mc), etc., and the material layer can be a compound such as silicon phosphide, silicon arsenide or silicon antimonide. In the present application, the closer to the surface of the photoelectric sensing region, the greater the mass of the material layer. Since the material layer is realized by doping with Group VA elements, the material layer with larger mass is arranged near the surface of the image sensor, which can increase the doping concentration at the center of the photoelectric sensing area and avoid the problem of low doping concentration on the surface of the photoelectric sensing area when using one compound to form the material layer. As a result, the material layers at different thicknesses in the photoelectric sensing area all have higher doping concentrations, thereby improving the quality of the image sensor.

[0068] See also Figures 4 to 8As shown, in one embodiment of the present invention, three material layers are arranged on the bottom isolation layer 104. That is, a first material layer 105, a second material layer 107 and a third material layer 108 are arranged on the bottom isolation layer 104. The first material layer 105 is located on the bottom isolation layer 104, the second material layer 107 is located on the first material layer 105, and the third material layer 108 is located on the second material layer 107. The first material layer 105 is a silicon phosphide layer, the second material layer 107 is a silicon arsenide layer, and the third material layer 108 is a silicon antimonide layer. The first material layer 105, the second material layer 107 and the third material layer 108 can be deposited by chemical vapor deposition.

[0069] See also Figures 4 to 6 As shown, in one embodiment of the present invention, the first material layer 105 is located on the bottom isolation layer 104, and a plurality of first grooves 1051 are provided in the first material layer 105. The positions of the first grooves 1051 can be set according to the requirements of the type of the photoelectric sensing area. When forming the first material layer 105, silicon source gas and phosphorus source gas are first introduced into the heated reaction chamber, and hydrogen is used as a carrier gas. The silicon source gas and the phosphorus source gas react at high temperature to generate silicon phosphide on the surface of the bottom isolation layer 104 as the first material layer 105. Then, a photoresist layer 106 is formed on the first material layer 105, and a first opening 1061 is formed on the photoresist layer 106. The first opening 1061 is used to define the position of the first groove 1051. Then, the first material layer 105 is dry-etched using the photoresist layer 106 as a mask to form the first groove 1051 in the first material layer 105. Among them, the first groove 1051 exposes the bottom isolation layer 104 at the bottom of the first material layer 105.

[0070] See also Figure 6 to Figure 7 As shown, in one embodiment of the present invention, after forming the first material layer 105, the second material layer 107 is formed on the first material layer 105. A plurality of second grooves 1071 are also provided in the second material layer 107. The second grooves 1071 are located on the first grooves 1051, and the depth of the second grooves 1071 is less than the depth of the first grooves 1051. When forming the second material layer 107, silicon source gas and arsenic source gas are introduced into the heated reaction chamber, and hydrogen is used as a carrier gas. The silicon source gas and the arsenic source gas react at high temperature to generate silicon arsenide on the surface of the first material layer 105 and in the first grooves 1051 as the second material layer 107. When forming the second material layer 107, since the first grooves 1051 are deep, the second material layer 107 located on the surface of the first material layer 105 is higher than the second material layer 107 located in the first grooves 1051, thereby forming the second grooves 1071 in the second material layer 107, and the second grooves 1071 are located on the first grooves 1051.

[0071] See also Figures 7 to 9 As shown, in one embodiment of the present invention, after forming the second material layer 107, a third material layer 108 is formed on the second material layer 107. The surface of the third material layer 108 is polished to form a third material layer 108 with a flat surface. When forming the third material layer 108, silicon source gas and antimony source gas are introduced into the heated reaction chamber, and hydrogen is used as a carrier gas. The silicon source gas and the antimony source gas react at high temperature to generate silicon antimonide on the surface of the bottom isolation layer 104 as the third material layer 108. There will also be shallow grooves on the surface of the deposited third material layer 108. After the third material layer 108 is deposited and formed, the surface of the third material layer 108 can be chemically mechanically polished to form a third material layer 108 with a flat surface.

[0072] See also Figures 9 to 11 As shown, in one embodiment of the present invention, after forming the third material layer 108, a top isolation layer 109 and a hard mask layer 110 are deposited on the third material layer 108, and the top isolation layer 109 is located on the third material layer 108, and the hard mask layer is located on the top isolation layer 109. Specifically, a layer of tantalum pentoxide with a high dielectric constant can be first deposited on the third material layer 108 as the top isolation layer 109, and then a layer of nitride can be deposited as the hard mask layer 110. Afterwards, the hard mask layer 110 is etched to form a second opening 1101 on the hard mask layer 110. The second opening 1101 is used to define the position of the deep trench isolation structure 112.

[0073] See also Figures 11 to 13 As shown, in one embodiment of the present invention, after forming a second opening 1101 on the hard mask layer 110, the top isolation layer 109, the third material layer 108, the second material layer 107, the first material layer 105 and a portion of the bottom isolation layer 104 at the bottom of the second opening 1101 are etched to form a deep trench 111 extending from the top isolation layer 109 to the bottom isolation layer 104. Then, a dielectric is deposited in the deep trench 111 to form a deep trench isolation structure 112. In this embodiment, the dielectric deposited in the deep trench 111 is, for example, silicon oxide (SiO 2 After the deep trench isolation structure 112 is formed, the top of the deep trench isolation structure 112 is chemically mechanically polished to remove the hard mask layer 110 and make the deep trench isolation structure 112 flush with the top isolation layer 109 .

[0074] See also Figures 4 to 13As shown, in one embodiment of the present invention, by forming a first groove 1051 in the first material layer 105, the second material layer 107 overlaps with the first material layer 105 in the growth direction, and a second groove 1071 is formed in the second material layer 107 above the first groove 1051. And because the second groove 1071 is formed in the second material layer 107, the third material layer 108 overlaps with the second material layer 107 in the growth direction. Afterwards, the first material layer 105, the second material layer 107 and the third material layer 108 are divided into multiple types of photoelectric sensing regions through isolation of the deep trench isolation structure 112.

[0075] See also Fig.13 As shown, in one embodiment of the present invention, the deep trench isolation structure 112 isolates the first material layer 105, the second material layer 107 and the third material layer 108 into three types of photoelectric sensing regions. The first type of photoelectric sensing region includes the first material layer 105, the second material layer 107 and the third material layer 108, and the second material layer 107 is located on the first material layer 105, and the third material layer 108 is located on the second material layer 107. The second type of photoelectric sensing region includes the first material layer 105 and the second material layer 107, and part of the second material layer 107 is located on the first material layer 105, part of the second material layer 107 is located in the first groove 1051, the third material layer 108 is located on the second material layer 107, and the third material layer 108 fills the second groove 1071. The third type of photoelectric sensing region includes the second material layer 107 and the third material layer 108, and the second material layer 107 is located on the isolation layer, and the third material layer 108 is located on the second material layer 107.

[0076] See also Fig.13 As shown, in the present application, due to the different types or structures of the material layers forming the photoelectric sensing regions, for the same light signal, different types of photoelectric sensing regions generate different electrons, thereby generating electrical signals of different intensities. In this embodiment, for the same light signal, the number of electrons generated by the first type of photoelectric sensing region is greater than the number of electrons generated by the second type of photoelectric sensing region, and the number of electrons generated by the second type of photoelectric sensing region is greater than the number of electrons generated by the third type of photoelectric sensing region. Therefore, when forming an image sensor, when different types of photoelectric sensing regions need to be formed, different types of photoelectric sensing regions can be formed by setting the position of the first groove 1051 and the position of the deep trench isolation structure 112.

[0077] See also Figures 4 to 13As shown, in the application, a multilayer material layer is formed by a layer-by-layer growth method, so that it is not easy to generate electron holes in the formed photoelectric sensing area, thereby improving the crosstalk between adjacent photoelectric sensing areas and between the photoelectric sensing area and other structural layers. At the same time, the deep trench isolation structure 112 and the bottom isolation layer 104 enclose the photoelectric sensing area, further reducing the crosstalk between adjacent photoelectric sensing areas. Furthermore, the present application uses a multilayer material layer to form a photoelectric sensing area, which can increase the electron concentration in the photoelectric sensing area, thereby increasing the intensity of the generated electrical signal. At the same time, in the present application, by forming different types of photoelectric sensing areas, electrical signals of different intensities can be generated for the same light signal, so that the same image sensor has a photoelectric sensing area that generates multiple electrical signals.

[0078] See also Figure 14 to Figure 15 As shown, in one embodiment of the present invention, after forming the material layer and the deep trench isolation structure 112, a grid 113 is formed on the deep trench isolation structure 112. The grid 113 is located on the deep trench isolation structure 112, and the orthographic projection of the grid 113 on the material layer covers the deep trench isolation structure 112. In the present application, the grid 113 includes a high dielectric constant material layer 1131, an aluminum metal layer 1132, and a titanium nitride layer 1133.

[0079] See also Figure 14 to Figure 15 As shown, in one embodiment of the present invention, a layer of tantalum pentoxide can be first deposited on the material layer and the deep trench isolation structure 112 as a high dielectric constant material layer 1131, and then a layer of metal aluminum can be deposited on the high dielectric constant material layer 1131 to form an aluminum metal layer 1132, and finally titanium nitride can be deposited on the aluminum metal layer 1132 to form a titanium nitride layer 1133. Among them, the thickness of the aluminum metal layer 1132 is much greater than the thickness of the high dielectric constant material layer 1131 and the titanium nitride layer 1133. Then, a photoresist is spin-coated on the titanium nitride layer 1133 to form a photoresist layer. Then, the photoresist layer is processed by exposure and development to form a patterned photoresist layer. And the titanium nitride layer 1133, the aluminum metal layer 1132 and the high dielectric constant material layer 1131 are etched using the patterned photoresist layer as a mask to form a grid 113. The high dielectric constant material layer 1131 in the grid 113 can better isolate the adjacent photoelectric sensing areas, the aluminum metal layer 1132 can play a good light shielding role, and the titanium nitride layer 1133 not only has high stability, but also has high reflectivity and anti-reflection performance, can reflect the incident light at the grid 113, and make the grid 113 more stable. Therefore, the formed grid 113 has a light shielding effect and can also reduce the generation of dark current.

[0080] See also Fig.15 As shown, in one embodiment of the present invention, the symmetry axes of the grid 113 and the deep trench isolation structure 112 in the growth direction are located on the same straight line.

[0081] See also Fig.16 As shown, in one embodiment of the present invention, after forming the grid 113, a filter is formed between adjacent grids 113, and the filter is located on the photoelectric sensing area. In this embodiment, the filter is a color filter 114 (ColorFilter, CF). Multiple color filters 114 filter monochromatic light of different spectra respectively, for example, for filtering to obtain red light, orange light, yellow light, green light, blue light, and purple light. Among them, the photoelectric sensing area, the deep trench isolation structure 112, the grid 113 and the color filter 114 form a pixel unit. After the incident light is focused and screened by the filter, the light of the set wavelength passes through the filter and reaches the photoelectric sensing area. Among them, the grid 113 and the deep trench isolation structure 112 can prevent the optical signals of different channels from crosstalking each other. The photoelectric sensing area receives the optical signal energy of the incident light to form a photocurrent. The present invention omits electrical connection structures such as pads, plugs and silicon through holes. The photocurrent is transmitted to the logic control area through the electrical connection structure. Through the processing of the logic control area, a variety of image processing results are formed.

[0082] In summary, the image sensor provided by the present invention includes a substrate, and the substrate has a first surface and a second surface relative to each other. In the substrate, a shallow trench isolation structure extending from the second surface to the substrate is provided. An etching stop layer and a metal layer interconnection layer are also provided on the second surface of the substrate. On one side of the first surface of the substrate, a bottom isolation layer is provided. On the bottom isolation layer, multiple material layers are provided. In the material layer, a deep trench isolation structure is provided, and the deep trench isolation structure isolates the material layer into various types of photoelectric sensing regions. On the deep trench isolation structure, a grid is also provided. On the photoelectric sensing region, a color filter is provided on the top isolation layer, on the top isolation layer, and between adjacent grids.

[0083] In summary, the image sensor and its manufacturing method provided by the present invention have the unexpected effect of using multiple layers of material layers to form a photoelectric sensing area, which can increase the electron concentration in the photoelectric sensing area, thereby increasing the intensity of the generated electrical signal. At the same time, the material layer is formed in a layer-by-layer growth manner, so that it is not easy to generate electron holes in the formed photoelectric sensing area, thereby improving the crosstalk between adjacent photoelectric sensing areas and between the photoelectric sensing area and other structural layers. In addition, in the present application, by forming different types of photoelectric sensing areas, electrical signals of different intensities can be generated for the same light signal, thereby meeting the needs of some image sensors for the formation of electrical signals of different intensities. In addition, the grid formed in the present application includes a high dielectric constant material layer, an aluminum metal layer and a titanium nitride layer, which can not only better isolate adjacent photoelectric sensing areas, but also play a better light shielding role, and can also reduce the generation of dark current.

[0084] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An image sensor, characterized in that: At least: substrate; A bottom isolation layer is disposed in the substrate, and the bottom isolation layer is bonded to a surface of the substrate; A plurality of material layers are arranged on the bottom isolation layer, and two adjacent material layers are arranged to overlap in the growth direction of the material layers; A deep trench isolation structure is disposed in the material layer, wherein the deep trench isolation structure isolates the material layer into multiple types of photoelectric sensing regions; A grid, disposed on the deep trench isolation structure; as well as A color filter is arranged on the photoelectric sensing area; Wherein, the multi-layer material layer comprises: A first material layer, wherein the first material layer is disposed on the bottom isolation layer, and a first groove is disposed in the first material layer, and the first groove exposes the bottom isolation layer; a second material layer, disposed on the first material layer, and the second material layer covers the first material layer and the first groove, a second groove is formed in the second material layer, and the second groove is located on the first groove; and The third material layer is disposed on the second material layer, and the third material layer covers the second material layer.

2. The image sensor according to claim 1, characterized in that The multiple types of photoelectric sensing regions include a first type of photoelectric sensing region, the first type of photoelectric sensing region includes the first material layer, the second material layer and the third material layer, the second material layer is located on the first material layer, and the third material layer is located on the second material layer.

3. The image sensor according to claim 1, characterized in that The multiple types of photoelectric sensing areas include a second type of photoelectric sensing area, the second type of photoelectric sensing area includes the first material layer, the second material layer and the third material layer, part of the second material layer is located on the first material layer, part of the second material layer is located in the first groove, the third material layer is located on the second material layer, and the third material layer fills the second groove.

4. The image sensor according to claim 1, characterized in that The multiple types of photoelectric sensing regions include a third type of photoelectric sensing region, and the third type of photoelectric sensing region includes the second material layer and the third material layer, the second material layer is located on the bottom isolation layer, and the third material layer is located on the second material layer.

5. The image sensor according to claim 1, characterized in that The image sensor comprises a top isolation layer, and the top isolation layer is located on a surface of the photoelectric sensing area.

6. The image sensor according to claim 1, characterized in that: The grid comprises a high dielectric constant material layer, an aluminum metal layer and a titanium nitride layer, wherein the high dielectric constant material layer is located on the deep trench isolation structure, the aluminum metal layer is located on the high dielectric constant material layer, and the titanium nitride layer is located on the aluminum metal layer.

7. A method for manufacturing an image sensor, characterized in that: The following steps are involved: providing a substrate, forming a bottom isolation layer in the substrate, wherein the bottom isolation layer is bonded to a surface of the substrate; forming a plurality of material layers on the bottom isolation layer, wherein two adjacent material layers are overlapped in the growth direction of the material layers; forming a deep trench isolation structure in the material layer, wherein the deep trench isolation structure isolates the material layer into multiple types of photoelectric sensing regions; forming a grid on the deep trench isolation structure; as well as forming a color filter on the photoelectric sensing area; and The formation of various types of photoelectric sensing regions includes the following steps: forming a first material layer on the bottom isolation layer, and forming a first groove in the first material layer; forming a second material layer on the first material layer, wherein the second material layer covers the first material layer, and forming a second groove in the second material layer; forming a third material layer on the second material layer; forming a top isolation layer and a hard mask layer on the third material layer; patterning the hard mask layer, and etching the top isolation layer, the third material layer, the second material layer, the first material layer, and a portion of the bottom isolation layer not covered by the hard mask layer to form a deep trench; and A dielectric is deposited in the deep trench to form a deep trench isolation structure, and the deep trench isolation structure isolates the first material layer, the second material layer and the third material layer into multiple types of photoelectric sensing regions.

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