Image sensor, manufacturing method thereof and graphical mask

Abstract

The invention discloses an image sensor and a manufacturing method thereof, and a patterned mask, and the manufacturing method of the image sensor comprises the steps: forming a patterned first photoresist layer on a first surface of a substrate, so as to form a plurality of first ion injection openings in the first photoresist layer; a patterned second photoresist layer is formed on the first surface of the substrate, a plurality of second ion injection openings are formed in the second photoresist layer, and the pattern of the first ion injection opening and the pattern of the second ion injection opening are the same and different in opening width; the patterns of the first ion injection opening and the second ion injection opening correspond to a first ion-doped isolation structure and a second ion-doped isolation structure in the substrate respectively, and the depth of the first ion-doped isolation structure in the substrate is greater than that of the second ion-doped isolation structure in the substrate. The width of the isolation structure in the depth direction is different, and the photosensitive area, the full well and the dynamic range can be increased while the good isolation effect is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of image sensors, and in particular to an image sensor, a manufacturing method thereof, and a patterned mask. Background Art

[0002] CMOS image sensors (CIS) are widely used in digital still cameras, cellular phones, security cameras, and in medical, automotive, and other applications. A typical image sensor operates in response to image light reflected from an external scene impinging on the image sensor. An image sensor includes an array of pixels having photosensitive elements (e.g., photodiodes) that absorb a portion of the incident image light and generate an image charge immediately upon absorbing the image light. The image charge for each pixel can be measured as an output voltage of each photosensitive element that varies with the incident image light. In other words, the amount of image charge generated is proportional to the intensity of the image light used to generate a digital image representing the external scene.

[0003] Figure 1 and Figure 2 As shown, a CMOS image sensor comprises multiple pixels arranged in an array, each containing a photodiode (PD). Isolation structures 20 isolate the multiple pixels. Isolation structures 20 are composed of first ion-doped isolation structure strips 21 in the row direction and second ion-doped isolation structure strips 22 in the column direction, which intersect each other. As the application requirements for CMOS image sensors become increasingly stringent, the corresponding pixel size requirements are becoming smaller and smaller, allowing more pixels to be obtained within the same area. From a pixel design perspective, the spacing between adjacent pixels is also reduced. The advantage of small pixels is that more pixels can be obtained within the same area. To achieve higher pixel counts and clearer images, it is necessary to obtain the same full well capacity as large pixels within a smaller photosensitive area. To achieve the same full well capacity within a smaller area, the depth of the pixel is often increased. For example, in terms of process, this means implanting the N-type ions that form the photodiode and the P-type ions that form the isolation structure 20 that isolates each pixel deeper.

[0004] Figures 3 to 5 As shown, when fabricating the isolation structure 20, it is necessary to coat the substrate 10 with a photoresist layer 30, pattern the photoresist layer 30 to form ion implantation openings 301 corresponding to the pattern of the isolation structure 20, and then perform ion implantation using the patterned photoresist layer 30 as a shield to form the isolation structure 20. However, the width of the isolation structure 20 obtained by only one doping process is relatively uniform in the depth direction. This results in low utilization of the photosensitive area and poor photosensitivity, particularly for small pixels. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies in the prior art, the present invention aims to provide an image sensor and a method for manufacturing the same, as well as a patterned mask, so as to solve the problems of low utilization of the photosensitive area and poor photosensitivity in the prior art.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The present invention provides a method for manufacturing an image sensor, the method comprising:

[0008] Providing a substrate; and fabricating an isolation structure in the substrate;

[0009] The manufacturing of the isolation structure includes the following steps:

[0010] forming a first photoresist layer on the first surface of the substrate, and patterning the first photoresist layer to form a plurality of first ion implantation openings on the first photoresist layer; and

[0011] forming a second photoresist layer on the first surface of the substrate, and patterning the second photoresist layer to form a plurality of second ion implantation openings on the second photoresist layer, wherein the pattern of the first ion implantation openings corresponds to the pattern of the second ion implantation openings, and the width of the first ion implantation openings is greater than the width of the second ion implantation openings;

[0012] The pattern of the first ion implantation opening corresponds to a first ion-doped isolation structure in the substrate, the pattern of the second ion implantation opening corresponds to a second ion-doped isolation structure in the substrate, the depth of the first ion-doped isolation structure in the substrate is greater than the depth of the second ion-doped isolation structure in the substrate, and the width of the first ion-doped isolation structure is greater than the width of the second ion-doped isolation structure;

[0013] forming the isolation structure in the image sensor based on the first ion-doped isolation structure and the second ion-doped isolation structure;

[0014] Semiconductor devices are fabricated between regions defined by the isolation structures on the first surface of the substrate to obtain the image sensor.

[0015] Furthermore, the manufacturing of the isolation structure specifically includes the following steps:

[0016] After patterning the first photoresist layer, performing a first ion implantation on the substrate using the patterned first photoresist layer as a shield to form a first ion doping isolation structure corresponding to the first ion implantation opening pattern in the substrate, and then stripping the first photoresist layer;

[0017] After patterning the second photoresist layer, the substrate is subjected to a second ion implantation using the patterned second photoresist layer as a shield to form a second ion doping isolation structure corresponding to the second ion implantation opening pattern in the substrate, and the second photoresist layer is stripped off.

[0018] Furthermore, the projections of the first ion implantation opening and the second ion implantation opening on the substrate are both grid structures with the same pattern and different opening widths; and / or the thickness of the first photoresist layer is greater than the thickness of the second photoresist layer.

[0019] Further, the first ion-doped isolation structure passes through the substrate, or the end of the first ion-doped isolation structure away from the first surface is spaced apart from the second surface of the substrate, and the first surface and the second surface are opposite surfaces on the substrate; and / or the length of the first ion-doped isolation structure is between 1 / 4 and 1 / 2 of the length of the second ion-doped isolation structure; and / or the first ion-doped isolation structure and the opposite sides of the second ion-doped isolation structure are in contact or overlap with each other; and / or the center of the first ion-doped isolation structure corresponds to the center of the second ion-doped isolation structure; and / or the isolation structure includes the first ion-doped isolation structure, the second ion-doped isolation structure to the Nth ion-doped isolation structure, N is an integer greater than or equal to 3, and the width gradually decreases from the first ion-doped isolation structure to the Nth ion-doped isolation structure.

[0020] Furthermore, the semiconductor device includes a photoelectric conversion element doping region, wherein the photoelectric conversion element doping region extends at least to the side of the first ion doping isolation structure facing the first surface, and / or the size of the photoelectric conversion element doping region close to the first surface is larger than the size away from the first surface.

[0021] Furthermore, the first photoresist layer includes a first region photoresist layer and a second region photoresist layer manufactured using different mask processes; and the manufacturing method of the isolation structure includes:

[0022] forming a first-region photoresist layer on the first surface of the substrate, and patterning the first-region photoresist layer using a single photolithography process, so as to form a plurality of first-region ion implantation openings on the first-region photoresist layer;

[0023] forming a second-region photoresist layer on the first surface of the substrate, and patterning the second-region photoresist layer using another photolithography process, forming a plurality of second-region ion implantation openings on the second-region photoresist layer, wherein the pattern of the first-region ion implantation openings and the pattern of the second-region ion implantation openings are interlaced;

[0024] The pattern of the first-region ion implantation opening corresponds to the first-region ion-doped isolation structure in the first ion-doped isolation structure, and the pattern of the second-region ion implantation opening corresponds to the second-region ion-doped isolation structure in the first ion-doped isolation structure;

[0025] The first ion-doped isolation structure in the isolation structure is formed based on the first-region ion-doped isolation structure and the second-region ion-doped isolation structure.

[0026] Furthermore, the production of the first ion-doped isolation structure specifically includes the following steps:

[0027] After patterning the first-region photoresist layer, performing first-region ion implantation on the substrate using the patterned first-region photoresist layer as a shield to form a first-region ion doping isolation structure corresponding to the first-region ion implantation opening pattern in the substrate, and stripping the first-region photoresist layer;

[0028] After patterning the second-region photoresist layer, the substrate is subjected to second-region ion implantation using the patterned second-region photoresist layer as a shield, forming a second-region ion doping isolation structure corresponding to the second-region ion implantation opening pattern in the substrate, and the second-region photoresist layer is stripped.

[0029] Furthermore, the projections of the first region ion implantation opening and the second region ion implantation opening on the substrate are both grid structures with staggered patterns, and the projections of the first region ion implantation opening and the second region ion implantation opening on the substrate together form the pattern of the first ion implantation opening.

[0030] Furthermore, the first photoresist layer includes a first region photoresist layer and a second region photoresist layer manufactured using different mask processes; and the manufacturing method of the isolation structure includes:

[0031] forming a first-region photoresist layer on the substrate and patterning the first-region photoresist layer to form a plurality of mutually parallel first photoresist strips, a plurality of first photoresist connecting portions, and a plurality of first-region ion implantation openings on the first-region photoresist layer, wherein the first-region ion implantation openings are parallel to the extension direction of the first photoresist strips, and the first photoresist connecting portion is located between two adjacent first-region ion implantation openings and connects the two adjacent first photoresist strips to each other;

[0032] Performing a first ion implantation on the substrate using the patterned first-region photoresist layer as a shield to form a first ion-doped isolation structure strip corresponding to the first-region ion implantation opening pattern in the substrate, and stripping the first-region photoresist layer, wherein the first ion-doped isolation structure strip has a first gap in a region corresponding to the first photoresist connection portion;

[0033] A second-region photoresist layer is formed on the substrate and patterned. A plurality of mutually parallel second photoresist strips, a plurality of second photoresist connecting portions, and a plurality of second-region ion implantation openings are formed on the second-region photoresist layer. The second-region ion implantation openings and the second photoresist strips extend in parallel with each other. The second photoresist connecting portion is located between two adjacent second-region ion implantation openings and connects the two adjacent second photoresist strips. The first photoresist connecting portion corresponds to the region of the second-region ion implantation openings, and the second photoresist connecting portion corresponds to the region of the first-region ion implantation openings.

[0034] Performing a second ion implantation on the substrate using the patterned second-region photoresist layer as a shield to form a second ion-doped isolation structure strip corresponding to the second-region ion implantation opening pattern in the substrate, and stripping the second photoresist layer, wherein the second ion-doped isolation structure strip has a second gap in a region corresponding to the second photoresist connection portion;

[0035] The first ion-doped isolation structure strip and the second ion-doped isolation structure strip together form the first ion-doped isolation structure in the isolation structure.

[0036] Furthermore, a third-region photoresist layer is used to replace the first-region photoresist layer and the second-region photoresist layer to form the first ion-doped isolation structure strip and the second ion-doped isolation structure strip, wherein the width of the first gap corresponding to the first ion-doped isolation strip is greater than the width of the second ion-doped isolation strip at the corresponding position; and / or the width of the second gap corresponding to the second ion-doped isolation strip is greater than the width of the first ion-doped isolation strip at the corresponding position, so as to correspond to the third photoresist connection portion in the third-region photoresist layer.

[0037] The present application also provides a patterned mask suitable for the method for manufacturing the image sensor described above, wherein the patterned mask includes a first sub-mask and a second sub-mask, the first sub-mask being provided with a first pattern, and the second sub-mask being provided with a second pattern, wherein:

[0038] The first pattern corresponds to the first photoresist layer after patterning, and the second pattern corresponds to the second photoresist layer after patterning.

[0039] Furthermore, the first photoresist layer includes a first-region photoresist layer and a second-region photoresist layer manufactured using different mask processes, the first sub-mask includes a first-region sub-mask and a second-region sub-mask, the first-region sub-mask is provided with a first pattern region, and the second-region sub-mask is provided with a second pattern region, wherein:

[0040] The first pattern region corresponds to the first-region photoresist layer after patterning, and the second pattern region corresponds to the second-region photoresist layer after patterning.

[0041] The present application also provides an image sensor, which is manufactured using the manufacturing method of the image sensor as described above, wherein the isolation structure includes a first ion-doped isolation structure and a second ion-doped isolation structure manufactured in steps using different ion implantation processes, the pattern of the first ion-doped isolation structure corresponds to the pattern of the second ion-doped isolation structure, the depth of the first ion-doped isolation structure in the substrate is greater than the depth of the second ion-doped isolation structure in the substrate, and the width of the first ion-doped isolation structure is greater than the width of the second ion-doped isolation structure.

[0042] Furthermore, projections of the first ion-doped isolation structure and the second ion-doped isolation structure on the substrate are both grid structures with the same pattern.

[0043] Furthermore, the first ion-doped isolation structure penetrates the substrate; or an end of the first ion-doped isolation structure away from the first surface is spaced apart from a second surface of the substrate, and the first surface and the second surface are opposite surfaces on the substrate.

[0044] Furthermore, the first ion-doped isolation structure includes a first-region ion-doped isolation structure and a second-region ion-doped isolation structure manufactured in steps using different ion implantation processes, and the pattern of the first-region ion-doped isolation structure and the pattern of the second-region ion-doped isolation structure are intertwined.

[0045] Furthermore, projections of the first-region ion-doped isolation structure and the second-region ion-doped isolation structure on the substrate are both grid-like structures with staggered patterns.

[0046] The beneficial effect of the present invention is that by using two photoresist layers with the same pattern and different opening widths, two ion doping treatments are performed respectively, and a first ion doping isolation structure and a second ion doping isolation structure with the same pattern and different widths are formed to jointly form an isolation structure in an image sensor, so that the width of the isolation structure in the depth direction is different. While ensuring a good isolation effect, the photosensitive area can be increased to improve the photosensitivity effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of the planar structure of an image sensor in the prior art;

[0048] Figure 2 is a schematic diagram of the cross-sectional structure of an image sensor in the prior art;

[0049] Figure 3-Figure 5 This is a schematic diagram of the process flow for manufacturing an isolation structure on an image sensor in the prior art;

[0050] Figure 6 1 is a schematic diagram of the planar structure of the image sensor in the first embodiment of the present invention;

[0051] Figure 7 is a schematic diagram of the longitudinal cross-sectional structure of the image sensor in the first embodiment of the present invention;

[0052] Figure 8a-8f 1. It is a schematic structural diagram of the process flow for manufacturing an isolation structure on an image sensor in the first embodiment of the invention;

[0053] Figure 9a-9l This is a schematic diagram of the process flow for manufacturing an isolation structure on an image sensor in the second embodiment of the invention;

[0054] Figure 10a-Figure 10e This is a schematic diagram of the process flow for manufacturing an isolation structure on an image sensor in the third embodiment of the invention;

[0055] Figure 11 1 is a schematic diagram of the planar structure of the third photoresist layer in another embodiment of the third embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0057] For example, when describing the embodiments of the present invention, cross-sectional views of device structures may be partially enlarged to scale for ease of explanation. Furthermore, these schematic views are merely illustrative and should not limit the scope of the present invention. Furthermore, in actual manufacturing, three-dimensional dimensions, including length, width, and depth, should be included.

[0058] For convenience, spatially relative terms such as "under," "below," "below," "below," "above," and "on" may be used herein to describe the relationship of one element or feature to other elements or features illustrated in the drawings. It will be understood that these spatially relative terms are intended to encompass orientations of the device in use or operation in addition to the orientation depicted in the drawings. Additionally, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0059] In the context of the present application, a structure described as a first feature being "above" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where an additional feature is formed between the first and second features, such that the first and second features may not be in direct contact.

[0060] 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 illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0061] [Example 1]

[0062] Figure 6 Schematic diagram of the planar structure of the image sensor in the first embodiment of the present invention. Figure 7 2 is a schematic diagram of the longitudinal cross-sectional structure of the image sensor in the first embodiment of the present invention. Figure 8a-8f This is a schematic diagram of the process flow for manufacturing an isolation structure on an image sensor in the first embodiment of the invention. Figure 6 and Figure 7 As shown, and reference Figure 8a - Figure 8 shows a method for manufacturing an image sensor according to a first embodiment of the present invention, the method comprising:

[0063] A substrate 10 is provided, wherein the substrate 10 is made of silicon, which can be single crystal silicon, single crystal germanium, polycrystalline silicon, amorphous silicon, or a silicon-germanium compound. There are no excessive restrictions on the type, size, structure, etc. of the substrate 10, and the specific selection can be made according to needs. The substrate 10 has a first surface 101 and a second surface 102 that are arranged opposite to each other. In one implementation, the substrate 10 may include a semiconductor substrate and an epitaxial layer formed on the semiconductor substrate. The various devices of the pixel circuit in the image sensor can be prepared in the epitaxial layer. In the case of this embodiment, the corresponding Figure 7 As shown in the related drawings, the substrate 10 can be understood as showing only a portion of the corresponding epitaxial layer, so as to prepare isolation and devices in the epitaxial layer.

[0064] An isolation structure 20 is fabricated in the substrate 10, wherein the fabrication of the isolation structure 20 includes the following steps:

[0065] like Figure 8a As shown, a first photoresist layer 31 is formed on the first surface 101 of the substrate 10, and a first mask (not shown) is used to pattern the first photoresist layer 31 (e.g., exposure and development). The first mask has a pattern corresponding to the first ion implantation openings 311, so that a plurality of first ion implantation openings 311 are formed in the first photoresist layer 31. The first photoresist layer 31 may be a photoresist layer, and may be a positive photoresist or a negative photoresist. However, the patterns of the light-transmitting and light-shielding areas on the first mask need to be changed accordingly.

[0066] like Figure 8b-Figure 8c As shown, after the first photoresist layer 31 is patterned, a first ion implantation is performed on the substrate 10 using the patterned first photoresist layer 31 as a shield, thereby forming a first ion-doped isolation structure 21 in the substrate 10 corresponding to the pattern of the first ion implantation opening 311. That is, the pattern of the first ion implantation opening 311 corresponds to the first ion-doped isolation structure 21 in the substrate 10. After the first ion implantation, the first photoresist layer 31 is then stripped.

[0067] like Figure 8dAs shown, a second photoresist layer 32 is formed on the first surface 101 of the substrate 10, and a second mask (not shown) is used to pattern the second photoresist layer 32 (e.g., exposure and development). The second mask has a pattern corresponding to the second ion implantation openings 321, so that a plurality of second ion implantation openings 321 are formed in the second photoresist layer 32. The pattern of the first ion implantation openings 311 corresponds to the pattern of the second ion implantation openings 321, and the width d1 of the first ion implantation openings 311 is greater than the width d2 of the second ion implantation openings 321. The second photoresist layer 32 can be a photoresist layer, and can be a positive photoresist or a negative photoresist. However, the patterns of the light-transmitting and light-blocking areas on the second mask need to be changed accordingly.

[0068] like Figure 8e-8f As shown, after the second photoresist layer 32 is patterned, a second ion implantation is performed on the substrate 10 using the patterned second photoresist layer 32 as a shield, forming a second ion-doped isolation structure 22 corresponding to the pattern of the second ion implantation opening 321 in the substrate 10. The second photoresist layer 32 is then stripped. That is, the pattern of the second ion implantation opening 321 corresponds to the second ion-doped isolation structure 22 in the substrate 10. After the second ion implantation, the second photoresist layer 32 on the substrate 10 is then stripped.

[0069] The depth of the first ion-doped isolation structure 21 within the substrate 10 is greater than the depth of the second ion-doped isolation structure 22 within the substrate 10, that is, the first ion-doped isolation structure 21 is located on the side of the substrate 10 close to the second surface 102, and the second ion-doped isolation structure 22 is located on the side of the substrate 10 close to the first surface 101. The width of the first ion-doped isolation structure 21 is greater than the width of the second ion-doped isolation structure 22. The isolation structure 20 in the image sensor is formed based on the first ion-doped isolation structure 21 and the second ion-doped isolation structure 22. By using two photoresist layers with the same pattern and different opening widths, performing two ion doping processes respectively, and forming the first ion-doped isolation structure 21 and the second ion-doped isolation structure 22 with the same pattern and different widths, the isolation structure 20 in the image sensor is formed. As a result, the width of the isolation structure 20 in the depth direction is different. While ensuring a good isolation effect, the photosensitive area can be increased, the full well is improved, and the dynamic range is increased to improve the imaging effect.

[0070] Furthermore, a semiconductor device (e.g., a photosensitive area PD) is fabricated between the areas defined by the isolation structure 20 on the first surface 101 of the substrate 10 to obtain an image sensor. Of course, other transistor structures may also be fabricated, such as a field effect transistor electrically connected to the photodiode. For example, the pixel may also include a transfer transistor TX having a transfer gate 41. In another example, a floating diffusion node FD is also formed in the pixel. Of course, other field effect transistors may also be included, such as a reset transistor RST, a source follower transistor SF, and a row select transistor RS, to form a 3T, 4T, 5T, and other pixel structures. In this embodiment, the types of the above-mentioned transistors are all selected as N-type, and it is understandable that they may also be P-type in their implementation. A metal interconnect layer 40 may also be fabricated on the first surface 101 of the substrate 10 to connect the transfer transistor TX, the reset transistor RST, the source follower transistor SF, and the row select transistor RS to form a signal transmission circuit.

[0071] In this embodiment, the projections of the first ion implantation openings 311 and the second ion implantation openings 321 on the substrate 10 are both a grid-like structure with the same pattern but different opening widths, thereby forming first ion-doped isolation structures 21 and second ion-doped isolation structures 22 with the same pattern but different widths within the substrate 10. The first ion-doped isolation structures 21 and the second ion-doped isolation structures 22 are both grid-like structures, defining multiple pixel regions. Because the depth of the first ion-doped isolation structures 21 within the substrate 10 is greater than the depth of the second ion-doped isolation structures 22 within the substrate 10, the energy required to form the first ion-doped isolation structures 21 is higher, and the thickness of the first photoresist layer 31 is greater than the thickness of the second photoresist layer 32.

[0072] In this embodiment, the isolation structure 20 penetrates the substrate 10, that is, the isolation structure 20 extends from the first surface 101 of the substrate 10 to the second surface 102 of the substrate 10. Of course, the end of the isolation structure 20 away from the first surface 101 may also be spaced apart from the second surface 102 of the substrate 10, that is, the isolation structure 20 is a non-through structure. For example, the isolation structure 20 may optionally penetrate the epitaxial layer on the semiconductor substrate Si.

[0073] Optionally, the length (i.e., height) of the first ion-doped isolation structure 21 is between 1 / 4 and 1 / 2 of the length (i.e., height) of the second ion-doped isolation structure 22, such as 1 / 3, so that the photosensitive area can be increased to a greater extent. The first ion-doped isolation structure 21 and the second ion-doped isolation structure 22 are in contact with each other on opposite sides or overlap with each other, so as to ensure that there is no gap between the first ion-doped isolation structure 21 and the second ion-doped isolation structure 22 after two doping treatments, so as to ensure that the isolation structure 20 has a better isolation effect. Optionally, the center of the first ion-doped isolation structure 21 corresponds to the center of the second ion-doped isolation structure 22 to improve the consistency of the signal response. Optionally, the maximum width of the first ion-doped isolation structure 21 is between 1 / 4 and 1 / 2 of the maximum width of the second ion-doped isolation structure 22, such as 1 / 3, which is conducive to taking into account both isolation and photosensitive optimization.

[0074] In an optional embodiment, the isolation structure includes a first ion-doped isolation structure, a second ion-doped isolation structure to an Nth ion-doped isolation structure, where N is an integer greater than or equal to 3, and the width gradually decreases from the first ion-doped isolation structure to the Nth ion-doped isolation structure, thereby increasing the area of the photosensitive region based on the ion-doped isolation structure with continuously decreasing width. When there are three or more ion-doped isolation structures in the isolation structure, multiple mask plates can be used for preparation in the preparation process. Furthermore, the thickness of the photoresist can be gradually reduced to optimize the process.

[0075] Furthermore, the semiconductor device includes a photoelectric conversion element doped region (e.g., an N-type doped region of the photosensitive region PD), wherein the photoelectric conversion element doped region extends at least to the side of the first ion-doped isolation structure 21 facing the first surface. In an optional example, the depth of the photoelectric conversion element doped region can be consistent with the depth of the isolation structure. Optionally, the photoelectric conversion element doped region extends through the substrate 10, for example, through the epitaxial layer. In the present application, the width of the first ion-doped isolation structure 21 is greater than the width of the second ion-doped isolation structure 22. Therefore, while ensuring device isolation performance, the photoelectric conversion element doped region can be increased by reducing the isolation area, thereby improving the quantum efficiency (QE) of the device. In addition, the size of the photoelectric conversion element doped region in the present application is larger near the first surface than away from the first surface. For front-illuminated image sensors (FSI), the absorption of short-wavelength optical signals can be improved, and for back-illuminated image sensors (BSI), the absorption of long-wavelength optical signals can be improved. In addition, the size of the photoelectric conversion element doped region in the present application is larger near the first surface (where pixel circuit transistors are arranged) than away from the first surface, which can optimize the electric field configuration and improve signal transmission.

[0076] like Figure 6and Figure 7 As shown, this embodiment also provides an image sensor fabricated using the above-described method for fabricating an image sensor. The isolation structure 20 includes a first ion-doped isolation structure 21 and a second ion-doped isolation structure 22, each fabricated in separate steps using different ion implantation processes. The first ion-doped isolation structure strips 21 are formed by a first ion implantation using a first photoresist layer 31, and the second ion-doped isolation structure strips 22 are formed by a second ion implantation using a second photoresist layer 32.

[0077] The pattern of the first ion-doped isolation structure 21 corresponds to the pattern of the second ion-doped isolation structure 22. The depth of the first ion-doped isolation structure 21 within the substrate 10 is greater than the depth of the second ion-doped isolation structure 22 within the substrate 10, and the width of the first ion-doped isolation structure 21 is greater than the width of the second ion-doped isolation structure 22. That is, the first ion-doped isolation structure 21 and the second ion-doped isolation structure 22 have the same pattern but different widths and different depths within the substrate 10. The first ion-doped isolation structure 21 and the second ion-doped isolation structure 22 together form the isolation structure 20 in the image sensor, resulting in different widths in the depth direction of the isolation structure 20. While ensuring a good isolation effect, the photosensitive area can be increased to improve the photosensitivity.

[0078] In this embodiment, the projections of the first ion-doped isolation structure 21 and the second ion-doped isolation structure 22 on the substrate 10 are both grid-like structures with the same pattern, so as to define and form a plurality of pixel areas.

[0079] In this embodiment, the isolation structure 20 passes through the substrate 10, that is, the isolation structure 20 extends from the first surface 101 of the substrate 10 to the second surface 102 of the substrate 10. Of course, the end of the isolation structure 20 away from the first surface 101 may also be spaced apart from the second surface 102 of the substrate 10, that is, the isolation structure 20 is a non-through structure. Optionally, the length (i.e., height) of the first ion-doped isolation structure 21 is between 1 / 4 and 1 / 2 of the length (i.e., height) of the second ion-doped isolation structure 22, thereby increasing the photosensitive area to a greater extent. The first ion-doped isolation structure 21 and the second ion-doped isolation structure 22 are in contact with each other on opposite sides or overlap with each other, thereby ensuring that there is no gap between the first ion-doped isolation structure 21 and the second ion-doped isolation structure 22 after two doping treatments, so as to ensure that the isolation structure 20 has a better isolation effect.

[0080] Furthermore, if Figure 7As shown, a semiconductor device (e.g., a photosensitive area PD) is fabricated between the areas defined by the isolation structure 20 on the first surface 101 of the substrate 10 to obtain an image sensor. Of course, other transistor structures can also be fabricated, such as a field effect transistor electrically connected to the photodiode. For example, the pixel can also include a transfer transistor TX having a transfer gate 41. In another example, a floating diffusion node FD is also formed in the pixel. Of course, other field effect transistors can also be included, such as a reset transistor RST, a source follower transistor SF, and a row select transistor RS, to form a 3T, 4T, 5T, and other pixel structures. Among them, the types of the above-mentioned transistors are all selected as N-type in this embodiment. It can be understood that they can also be P-type in their implementation methods. A metal interconnect layer 40 can also be fabricated on the first surface 101 of the substrate 10 to connect the transfer transistor TX, the reset transistor RST, the source follower transistor SF, and the row select transistor RS to form a signal transmission circuit.

[0081] [Example 2]

[0082] Figure 9a-9l FIG. 1 is a schematic diagram of a process flow for manufacturing an isolation structure on an image sensor in the second embodiment of the invention. Figure 9a-9l As shown, the image sensor and its manufacturing method provided by the second embodiment of the present invention are similar to those provided by the first embodiment ( Figures 6 to 8f ) and the manufacturing method thereof are substantially the same, except that, in this embodiment:

[0083] A substrate 10 is provided. The substrate 10 is made of silicon, and may be single crystal silicon, single crystal germanium, polycrystalline silicon, amorphous silicon, or a silicon-germanium compound. The type, size, and structure of the substrate 10 are not particularly limited and may be selected based on specific needs. The substrate 10 has a first surface 101 and a second surface 102 disposed opposite each other.

[0084] An isolation structure 20 is fabricated in the substrate 10, wherein the fabrication of the isolation structure 20 includes the following steps:

[0085] A first photoresist layer 31 is formed on the first surface 101 of the substrate 10 . The first photoresist layer 31 includes a first region photoresist layer 31 a and a second region photoresist layer 31 b that are formed using different mask processes.

[0086] like Figure 9aAs shown, a first-region photoresist layer 31a is formed on the first surface 101 of the substrate 10 and patterned using a single photolithography process. Specifically, a single mask (not shown) is used to pattern the first-region photoresist layer 31a (e.g., exposure and development) to form a plurality of first-region ion implantation openings 311a in the first-region photoresist layer 31a. The first-region ion implantation openings 311a are portions of the pattern of the first ion implantation openings 311. The first-region photoresist layer 31a can be a photoresist layer, and can be either a positive photoresist or a negative photoresist. However, the patterns of the light-transmitting and light-shielding regions on the mask need to be modified accordingly.

[0087] like Figure 9b-9d As shown, after patterning the first-region photoresist layer 31a, first-region ion implantation is performed on the substrate 10 using the patterned first-region photoresist layer 31a as a shield, thereby forming a first-region ion-doped isolation structure 21a corresponding to the pattern of the first-region ion implantation opening 311a in the substrate 10. After the first-region ion implantation, the first-region photoresist layer 31a is then stripped.

[0088] like Figure 9e As shown, a second-region photoresist layer 31b is formed on the first surface 101 of the substrate 10, and another photolithography process is used to pattern the second-region photoresist layer 31b. Specifically, another mask (not shown) is used to pattern the second-region photoresist layer 31b (e.g., exposure and development) to form a plurality of second-region ion implantation openings 311b on the second-region photoresist layer 31b. The second-region ion implantation openings 311b are another portion of the pattern of the first ion implantation openings 311. The pattern of the first-region ion implantation openings 311a and the pattern of the second-region ion implantation openings 311b intersect with each other, and the pattern of the first-region ion implantation openings 311a and the pattern of the second-region ion implantation openings 311b together form the pattern of the first ion implantation openings 311. The second-region photoresist layer 31b can be a photoresist layer, and can be a positive photoresist or a negative photoresist. However, the patterns of the light-transmitting and light-blocking regions on the mask need to be changed accordingly.

[0089] like Figure 9f-9h As shown, after patterning the second-region photoresist layer 31b, the substrate 10 is subjected to second-region ion implantation using the patterned second-region photoresist layer 31b as a shield, thereby forming a second-region ion-doped isolation structure 21b corresponding to the pattern of the second-region ion implantation opening 311b in the substrate 10. After the first-region ion implantation, the second-region photoresist layer 31b is then stripped.

[0090] Among them, such as Figure 9d 、 Figure 9h as well as Figure 9i As shown, the pattern of the first-region ion-implantation openings 311a corresponds to the first-region ion-implantation isolation structure 21a in the first ion-doped isolation structure 21, and the pattern of the second-region ion-implantation openings 311b corresponds to the second-region ion-doped isolation structure 21b in the first ion-doped isolation structure 21. The first-region ion-doped isolation structure 21a and the second-region ion-doped isolation structure 21b form the first ion-doped isolation structure 21 in the isolation structure 20. Because the depth of the first ion-doped isolation structure 21 within the substrate 10 is greater than the depth of the second ion-doped isolation structure 22 within the substrate 10, the thickness of the first photoresist layer 31 is greater than the thickness of the second photoresist layer 32. In this embodiment, by using two photoresist layers with different but identical patterns, performing two ion doping processes respectively, and forming the first-region ion-doped isolation structure 21a and the second-region ion-doped isolation structure 21b with different but identical patterns, the first ion-doped isolation structure 21a and the second-region ion-doped isolation structure 21b are formed together to form the first ion-doped isolation structure 21. This prevents the first-region photoresist layer 31a and the second-region photoresist layer 31b from collapsing.

[0091] In this embodiment, the projections of the first region ion implantation openings 311a and the second region ion implantation openings 311b on the substrate 10 both form a grid-like structure with interlaced patterns. Together, the projections of the first region ion implantation openings 311a and the second region ion implantation openings 311b on the substrate 10 form the pattern of the first ion implantation openings 311. This allows the grid size of the first region ion implantation openings 311a and the second region ion implantation openings 311b to be increased, thereby preventing the first region photoresist layer 31a and the second region photoresist layer 31b from collapsing.

[0092] like Figure 9j As shown, a second photoresist layer 32 is formed on the first surface 101 of the substrate 10, and a second mask (not shown) is used to pattern the second photoresist layer 32 (e.g., exposure and development). The second mask has a pattern corresponding to the second ion implantation openings 321, so that a plurality of second ion implantation openings 321 are formed in the second photoresist layer 32. The pattern of the first ion implantation openings 311 corresponds to the pattern of the second ion implantation openings 321, and the width d1 of the first ion implantation openings 311 is greater than the width d2 of the second ion implantation openings 321. The second photoresist layer 32 can be a photoresist layer, and can be a positive photoresist or a negative photoresist. However, the patterns of the light-transmitting and light-blocking areas on the second mask need to be changed accordingly.

[0093] like Figure 9k-9lAs shown, after the second photoresist layer 32 is patterned, a second ion implantation is performed on the substrate 10 using the patterned second photoresist layer 32 as a shield, forming a second ion-doped isolation structure 22 corresponding to the pattern of the second ion implantation opening 321 in the substrate 10. The second photoresist layer 32 is then stripped. That is, the pattern of the second ion implantation opening 321 corresponds to the second ion-doped isolation structure 22 in the substrate 10. After the second ion implantation, the second photoresist layer 32 on the substrate 10 is then stripped.

[0094] This embodiment also provides an image sensor, which is manufactured using the above-mentioned method for manufacturing an image sensor. Figure 9d 、 Figure 9h as well as Figure 9i As shown, the first ion-doped isolation structure 21 includes a first region ion-doped isolation structure 21a and a second region ion-doped isolation structure 21b which are manufactured in steps using different ion implantation processes, and the pattern of the first region ion-doped isolation structure 21a and the pattern of the second region ion-doped isolation structure 21b are intertwined.

[0095] The projections of the first-region ion-doped isolation structure 21a and the second-region ion-doped isolation structure 21b on the substrate 10 are both grid-like structures with interlaced patterns. The grid size of the first-region ion implantation openings 311a and the second-region ion implantation openings 311b can be increased to prevent the first-region photoresist layer 31a and the second-region photoresist layer 31b from collapsing.

[0096] It should be understood by those skilled in the art that the remaining structures and working principles of this embodiment are the same as those of the first embodiment and will not be described in detail here.

[0097] [Example 3]

[0098] Figure 10a-Figure 10e This is a schematic diagram of the process flow for manufacturing an isolation structure on an image sensor in the third embodiment of the invention. Figure 10a-Figure 10e As shown, the image sensor and its manufacturing method provided by the third embodiment of the present invention are similar to those provided by the second embodiment ( Figures 9a to 91 ) and the manufacturing method thereof are substantially the same, except that, in this embodiment:

[0099] A substrate 10 is provided. The substrate 10 is made of silicon, and may be single crystal silicon, single crystal germanium, polycrystalline silicon, amorphous silicon, or a silicon-germanium compound. The type, size, and structure of the substrate 10 are not particularly limited and may be selected based on specific needs. The substrate 10 has a first surface 101 and a second surface 102 disposed opposite each other.

[0100] An isolation structure 20 is fabricated in the substrate 10, wherein the fabrication of the isolation structure 20 includes the following steps:

[0101] A first photoresist layer 31 is formed on the first surface 101 of the substrate 10 . The first photoresist layer 31 includes a first region photoresist layer 31 a and a second region photoresist layer 31 b that are formed using different mask processes.

[0102] like Figure 10a As shown, a first-region photoresist layer 31a is formed on the first surface 101 of the substrate 10, and a single photolithography process is used to pattern the first-region photoresist layer 31a. That is, a mask (not shown) is used to pattern the first-region photoresist layer 31a (e.g., exposure and development), so that a plurality of mutually parallel first photoresist strips 31a1, a plurality of first photoresist connecting portions 31a2, and a plurality of first-region ion implantation openings 311a are formed on the first-region photoresist layer 31a. The first-region ion implantation openings 311a and the extension of the first photoresist strips 31a1 are parallel to each other. The first photoresist connecting portion 31a2 is located between two adjacent first-region ion implantation openings 311a and connects two adjacent first photoresist strips 31a1. Specifically, two first-region ion implantation openings 311a on the same straight line are separated from each other by the first photoresist connecting portion 31a2. This allows all first photoresist strips 31a1 to be connected together by the first photoresist connecting portion 31a2 to form a single unit, thereby providing greater stability and preventing the problem of photoresist collapse and shedding when fabricating the isolation structure of a small-sized image sensor. The first-region ion implantation openings 311a are portions of the pattern of the first ion implantation openings 311. The first-region photoresist layer 31a can be a photoresist layer, and can use either positive or negative photoresist. However, the patterns of the light-transmitting and light-shielding regions on the mask need to be modified accordingly.

[0103] like Figure 10b As shown, after patterning the first-region photoresist layer 31a, first-region ion implantation is performed on the substrate 10 using the patterned first-region photoresist layer 31a as a shield, thereby forming first-region ion-doped isolation structures 21a corresponding to the pattern of the first-region ion implantation openings 311a in the substrate 10. The first ion-doped isolation structure strips 21a have first gaps 211a in the regions corresponding to the first photoresist connection portions 31a2. That is, two first ion-doped isolation structure strips 21a on the same straight line are separated from each other by the first gaps 211a. After the first-region ion implantation, the first-region photoresist layer 31a is then stripped.

[0104] like Figure 10cAs shown, a second-region photoresist layer 31b is formed on the first surface 101 of the substrate 10, and another photolithography process is used to pattern the second-region photoresist layer 31b, that is, another mask (not shown) is used to pattern the second-region photoresist layer 31b (for example, exposure and development), so that a plurality of mutually parallel second photoresist strips 31b1, a plurality of second photoresist connecting portions 31b2, and a plurality of second-region ion implantation openings 311b are formed on the second-region photoresist layer 31b. The second-region ion implantation openings 311b and the second photoresist strips 31b1 are parallel to each other. The extension directions are parallel to each other. The second photoresist connecting portion 31b2 is located between two adjacent second-region ion implantation openings 311b and connects two adjacent second photoresist strips 31b1. That is, two second-region ion implantation openings 311b on the same straight line are separated from each other by the second photoresist connecting portion 31b2, so that all second photoresist strips 31b1 are connected together by the second photoresist connecting portion 31b2 to form a whole, thereby providing better stability and avoiding the problem of photoresist collapse and falling off when manufacturing the isolation structure of a small-sized image sensor. Among them, the second-region ion implantation openings 311b are another part of the pattern of the first ion implantation openings 311. The first photoresist connecting portion 31a2 corresponds to the area of the second-region ion implantation openings 311b, and the second photoresist connecting portion 31b2 corresponds to the area of the first-region ion implantation openings 311a. The pattern of the first-region ion implantation openings 311a and the pattern of the second-region ion implantation openings 311b together form the pattern of the first ion implantation openings 3111. The second region photoresist layer 31 b may be a photoresist layer, and may be a positive photoresist or a negative photoresist. However, the patterns of the light-transmitting area and the light-shielding area on the mask need to be changed accordingly.

[0105] like Figure 10d As shown, after patterning the second-region photoresist layer 31b, the second-region ion implantation is performed on the substrate 10 using the patterned second-region photoresist layer 31b as a shield, forming a second-region ion-doped isolation structure 21b corresponding to the pattern of the second-region ion implantation opening 311b in the substrate 10. The second ion-doped isolation structure strip 21b has a second gap 211b in the region corresponding to the second photoresist connection portion 31b2. After the first-region ion implantation, the second-region photoresist layer 31b is then stripped.

[0106] like Figure 10eAs shown, the first ion-doped isolation structure 21 in the isolation structure 20 is formed based on the first-region ion-doped isolation structure 21a and the second-region ion-doped isolation structure 21b. After the first-region ion implantation and the second-region ion implantation, the first ion-doped isolation structure strip 21a has a first gap 211a in the region corresponding to the second ion-doped isolation structure strip 21b, and the second ion-doped isolation structure strip 21b has a second gap 211b in the region corresponding to the first ion-doped isolation structure strip 21a. This ensures that the first ion-doped isolation structure strip 21a and the second ion-doped isolation structure strip 21b jointly form the isolation structure 20 in the image sensor, avoiding repeated ion implantation of the isolation structure 20 into the substrate 10 in the first gap 211a and the second gap 211b, which affects the doping uniformity of the isolation structure 20.

[0107] Figure 11 FIG. 1 is a schematic diagram of the planar structure of the third photoresist layer in another embodiment of the third embodiment of the present invention. Figure 11 As shown, in another embodiment, a third photoresist layer 33 is used to replace the first and second region photoresist layers 31a and 31b to form the first and second region ion-doped isolation structures 21a and 21b. The third photoresist layer 33 has a third ion implantation opening 331 and a third photoresist connector 332. The third ion implantation opening 331 replaces the first and second region ion implantation openings 311a and 311b, and the third photoresist connector 332 replaces the first and second photoresist connectors 31a2 and 31b2. The first gap 211 corresponding to the first ion-doped isolation strip 21 has a greater width than the second ion-doped isolation strip 22 at the corresponding location, and / or the second gap 221 corresponding to the second ion-doped isolation strip 22 has a greater width than the first ion-doped isolation strip 21 at the corresponding location, thereby forming the third photoresist connector 332 in the third photoresist layer 33, thereby forming the isolation structure 20. In this embodiment, the design based on the photoresist connector can alleviate photoresist collapse, thereby saving process costs.

[0108] It should be understood by those skilled in the art that the remaining structures and working principles of this embodiment are the same as those of the second embodiment and will not be described in detail here.

[0109] The present application also provides a patterned mask suitable for use in the method for fabricating an isolation structure as described in any of the above-mentioned solutions. The patterned mask includes a first sub-mask and a second sub-mask, wherein the first sub-mask is provided with a first pattern, and the second sub-mask is provided with a second pattern, wherein: the first pattern corresponds to the patterned first photoresist layer 31, i.e., the first photoresist layer 31 is patterned based on the first sub-mask; and the second pattern corresponds to the patterned second photoresist layer 32, i.e., the second photoresist layer 32 is patterned based on the second sub-mask.

[0110] Furthermore, corresponding to the manufacturing method of the isolation structure in the second and third embodiments, the first photoresist layer 31 includes a first-region photoresist layer 31a and a second-region photoresist layer 31b manufactured using different mask processes, and the first sub-mask includes a first-region sub-mask and a second-region sub-mask. The first-region sub-mask is provided with a first pattern region, and the second-region sub-mask is provided with a second pattern region. The first pattern region corresponds to the patterned first-region photoresist layer 31a, that is, the first-region photoresist layer 31a is patterned based on the first-region sub-mask; the second pattern region corresponds to the patterned second-region photoresist layer 31b, that is, the second-region photoresist layer 31b is patterned based on the second-region sub-mask.

[0111] In this document, directional terms such as "up," "down," "left," "right," "front," and "back" are defined based on the positions of structures in the accompanying drawings and their relative positions to each other, for the sake of clarity and convenience in presenting the technical solution. It should be understood that the use of these directional terms does not limit the scope of protection claimed in this application. It should also be understood that the terms "first" and "second," etc., used herein, are used solely for distinctions and are not intended to limit quantity or order.

[0112] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to the technical contents disclosed above without departing from the scope of the technical solution of the present invention, which are equivalent embodiments of equivalent changes. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A method for manufacturing an image sensor, characterized in that: The production method comprises: providing a substrate; fabricating an isolation structure in the substrate; The manufacturing of the isolation structure includes the following steps: forming a first photoresist layer on the first surface of the substrate, and patterning the first photoresist layer to form a plurality of first ion implantation openings on the first photoresist layer; and forming a second photoresist layer on the first surface of the substrate, and patterning the second photoresist layer to form a plurality of second ion implantation openings on the second photoresist layer, wherein the pattern of the first ion implantation openings corresponds to the pattern of the second ion implantation openings, and the width of the first ion implantation openings is greater than the width of the second ion implantation openings; The pattern of the first ion implantation opening corresponds to a first ion-doped isolation structure in the substrate, the pattern of the second ion implantation opening corresponds to a second ion-doped isolation structure in the substrate, the depth of the first ion-doped isolation structure in the substrate is greater than the depth of the second ion-doped isolation structure in the substrate, and the width of the first ion-doped isolation structure is greater than the width of the second ion-doped isolation structure; forming the isolation structure in the image sensor based on the first ion-doped isolation structure and the second ion-doped isolation structure; and Semiconductor devices are fabricated between regions defined by the isolation structures on the first surface of the substrate to obtain the image sensor.

2. The method for manufacturing an image sensor according to claim 1, wherein: The production of the isolation structure specifically includes the following steps: After patterning the first photoresist layer, performing a first ion implantation on the substrate using the patterned first photoresist layer as a shield to form a first ion doping isolation structure corresponding to the first ion implantation opening pattern in the substrate, and then stripping the first photoresist layer; After patterning the second photoresist layer, the substrate is subjected to a second ion implantation using the patterned second photoresist layer as a shield to form a second ion doping isolation structure corresponding to the second ion implantation opening pattern in the substrate, and the second photoresist layer is stripped off.

3. The method for manufacturing an image sensor according to claim 1, wherein: Projections of the first ion implantation opening and the second ion implantation opening on the substrate are both grid-like structures with the same pattern and different opening widths.

4. The method for manufacturing an image sensor according to claim 1, wherein: The first ion-doped isolation structure penetrates the substrate, or an end of the first ion-doped isolation structure away from the first surface is spaced apart from a second surface of the substrate, and the first surface and the second surface are opposite surfaces on the substrate; And / or, the first ion-doped isolation structure and the second ion-doped isolation structure are in contact with each other or overlap with each other on opposite sides; and / or, the center of the first ion-doped isolation structure corresponds to the center of the second ion-doped isolation structure; and / or, the isolation structure includes the first ion-doped isolation structure, the second ion-doped isolation structure to the Nth ion-doped isolation structure, N is an integer greater than or equal to 3, and the width gradually decreases from the first ion-doped isolation structure to the Nth ion-doped isolation structure.

5. The method for manufacturing an image sensor according to claim 1, wherein: The first photoresist layer includes a first region photoresist layer and a second region photoresist layer made by different mask processes; The manufacturing method of the isolation structure includes: forming a first-region photoresist layer on the first surface of the substrate, and patterning the first-region photoresist layer using a single photolithography process, so as to form a plurality of first-region ion implantation openings on the first-region photoresist layer; forming a second-region photoresist layer on the first surface of the substrate, and patterning the second-region photoresist layer using another photolithography process, forming a plurality of second-region ion implantation openings on the second-region photoresist layer, wherein the pattern of the first-region ion implantation openings and the pattern of the second-region ion implantation openings are interlaced; The pattern of the first-region ion implantation opening corresponds to the first-region ion-doped isolation structure in the first ion-doped isolation structure, and the pattern of the second-region ion implantation opening corresponds to the second-region ion-doped isolation structure in the first ion-doped isolation structure; The first ion-doped isolation structure in the isolation structure is formed based on the first-region ion-doped isolation structure and the second-region ion-doped isolation structure.

6. The method for manufacturing an image sensor according to claim 5, wherein: The production of the first ion-doped isolation structure specifically includes the following steps: After patterning the first-region photoresist layer, performing first-region ion implantation on the substrate using the patterned first-region photoresist layer as a shield to form a first-region ion doping isolation structure corresponding to the first-region ion implantation opening pattern in the substrate, and stripping the first-region photoresist layer; After patterning the second-region photoresist layer, the substrate is subjected to second-region ion implantation using the patterned second-region photoresist layer as a shield, forming a second-region ion doping isolation structure corresponding to the second-region ion implantation opening pattern in the substrate, and the second-region photoresist layer is stripped.

7. The method for manufacturing an image sensor according to claim 5, wherein: The projections of the first region ion implantation opening and the second region ion implantation opening on the substrate are both grid structures with staggered patterns, and the projections of the first region ion implantation opening and the second region ion implantation opening on the substrate together form the pattern of the first ion implantation opening.

8. The method for manufacturing an image sensor according to claim 1, wherein: The first photoresist layer includes a first region photoresist layer and a second region photoresist layer made by different mask processes; The manufacturing method of the isolation structure includes: forming a first-region photoresist layer on the substrate and patterning the first-region photoresist layer to form a plurality of mutually parallel first photoresist strips, a plurality of first photoresist connecting portions, and a plurality of first-region ion implantation openings on the first-region photoresist layer, wherein the first-region ion implantation openings are parallel to the extension direction of the first photoresist strips, and the first photoresist connecting portion is located between two adjacent first-region ion implantation openings and connects the two adjacent first photoresist strips to each other; Performing a first ion implantation on the substrate using the patterned first-region photoresist layer as a shield to form a first ion-doped isolation structure strip corresponding to the first-region ion implantation opening pattern in the substrate, and stripping the first-region photoresist layer, wherein the first ion-doped isolation structure strip has a first gap in a region corresponding to the first photoresist connection portion; A second-region photoresist layer is formed on the substrate and patterned. A plurality of mutually parallel second photoresist strips, a plurality of second photoresist connecting portions, and a plurality of second-region ion implantation openings are formed on the second-region photoresist layer. The second-region ion implantation openings and the second photoresist strips extend in parallel with each other. The second photoresist connecting portion is located between two adjacent second-region ion implantation openings and connects the two adjacent second photoresist strips. The first photoresist connecting portion corresponds to the region of the second-region ion implantation openings, and the second photoresist connecting portion corresponds to the region of the first-region ion implantation openings. Performing a second ion implantation on the substrate using the patterned second-region photoresist layer as a shield to form a second ion-doped isolation structure strip corresponding to the second-region ion implantation opening pattern in the substrate, and stripping the second photoresist layer, wherein the second ion-doped isolation structure strip has a second gap in a region corresponding to the second photoresist connection portion; The first ion-doped isolation structure strip and the second ion-doped isolation structure strip together form the first ion-doped isolation structure in the isolation structure.

9. The method for manufacturing an image sensor according to claim 8, wherein: A third-region photoresist layer is used to replace the first-region photoresist layer and the second-region photoresist layer to form the first ion-doped isolation structure strip and the second ion-doped isolation structure strip, wherein the width of the first gap corresponding to the first ion-doped isolation strip is greater than the width of the second ion-doped isolation strip at the corresponding position; and / or the width of the second gap corresponding to the second ion-doped isolation strip is greater than the width of the first ion-doped isolation strip at the corresponding position, so as to correspond to the third photoresist connection portion in the third-region photoresist layer.

10. The method for manufacturing an image sensor according to any one of claims 1 to 9, wherein: The semiconductor device includes a photoelectric conversion element doping region, wherein the photoelectric conversion element doping region at least extends to a side of the first ion doping isolation structure facing the first surface, and / or the size of the photoelectric conversion element doping region close to the first surface is larger than the size away from the first surface.

11. A patterned mask suitable for the method for manufacturing an image sensor according to any one of claims 1 to 10, characterized in that: The patterned mask includes a first sub-mask and a second sub-mask, the first sub-mask is provided with a first pattern, and the second sub-mask is provided with a second pattern, wherein: The first pattern corresponds to the first photoresist layer after patterning, and the second pattern corresponds to the second photoresist layer after patterning.

12. The patterned mask according to claim 11, wherein: The first photoresist layer includes a first-region photoresist layer and a second-region photoresist layer manufactured using different mask processes. The first sub-mask includes a first-region sub-mask and a second-region sub-mask. The first-region sub-mask is provided with a first pattern region, and the second-region sub-mask is provided with a second pattern region. The first pattern region corresponds to the first-region photoresist layer after patterning, and the second pattern region corresponds to the second-region photoresist layer after patterning.

13. An image sensor, characterized in that: The image sensor is manufactured using the manufacturing method according to any one of claims 1 to 10, wherein the isolation structure includes a first ion-doped isolation structure and a second ion-doped isolation structure manufactured in steps using different ion implantation processes, the pattern of the first ion-doped isolation structure corresponds to the pattern of the second ion-doped isolation structure, the depth of the first ion-doped isolation structure in the substrate is greater than the depth of the second ion-doped isolation structure in the substrate, and the width of the first ion-doped isolation structure is greater than the width of the second ion-doped isolation structure.

14. The image sensor according to claim 13, wherein: Projections of the first ion-doped isolation structure and the second ion-doped isolation structure on the substrate are both grid-like structures with the same pattern; and / or, the first ion-doped isolation structure penetrates the substrate; Or an end of the first ion-doped isolation structure away from the first surface is spaced apart from the second surface of the substrate, and the first surface and the second surface are opposite surfaces on the substrate.

15. The image sensor according to any one of claims 13 to 14, characterized in that: The first ion-doped isolation structure includes a first-region ion-doped isolation structure and a second-region ion-doped isolation structure that are manufactured in steps using different ion implantation processes. The pattern of the first-region ion-doped isolation structure and the pattern of the second-region ion-doped isolation structure are interlaced.

16. The image sensor according to claim 15, wherein: Projections of the first-region ion-doped isolation structure and the second-region ion-doped isolation structure on the substrate are both grid-like structures with staggered patterns.

Images