Image sensor structure, manufacturing method and electronic device

Abstract

The present application provides an image sensor structure, a manufacturing method and an electronic device, wherein the image sensor structure includes a photodiode layer, a dielectric layer and a filter layer, wherein the photodiode layer and the dielectric layer are stacked in sequence, and the dielectric layer includes a plurality of grooves; the filter layer includes a plurality of filter films with different wavelengths of transmitted light, and each filter film fills a corresponding groove; the target distance between the bottom wall of each groove and the photodiode layer is different, and the target distance is determined based on the wavelength range of light allowed to be transmitted by the filter film. Therefore, at the target distance, due to destructive interference between the light reflected from the surface of the dielectric layer and the light reflected from the surface of the photodiode layer, the intensity of the reflected light is greatly reduced, thereby allowing the light allowed to be transmitted by the filter film to be more transmitted into the photodiode layer, generating more photoelectrons, enhancing the quantum efficiency of the incident light, and thus improving the image quality.

Description

Technical Field

[0001] The present application relates to the field of image sensors, and in particular to an image sensor structure, a manufacturing method and an electronic device. Background Art

[0002] With the continuous development of back-illuminated CMOS image sensors (CIS), people's requirements for CIS structures are also increasing. As the light-incoming window of the photodiode in the CIS structure, the back metal grating (BMG) also needs to have better light intake and light selectivity. However, in the traditional CIS structure, the light energy incident on the photodiode is relatively small, and the quantum efficiency (QE) is low. Summary of the invention

[0003] In view of this, the purpose of this application is to provide an image sensor structure, a manufacturing method and an electronic device, which enhance the quantum efficiency of incident light and thus improve image quality. The specific scheme is as follows:

[0004] The present application provides an image sensor structure, comprising:

[0005] A photodiode layer and a dielectric layer stacked in sequence, wherein the dielectric layer comprises a plurality of grooves;

[0006] A filter layer, the filter layer comprising a plurality of filter films with different wavelengths of transmitted light, each of the filter films corresponding to one of the grooves;

[0007] The target distance between the bottom wall of each groove and the photodiode layer is different, and the target distance is determined based on the wavelength range of light allowed to pass through the filter film.

[0008] Optionally, the target distance is greater than or equal to a first distance and less than or equal to a second distance, the first distance is an integer multiple of one quarter of the minimum wavelength of light allowed to pass through the filter film, and the second distance is an integer multiple of one quarter of the maximum wavelength of light allowed to pass through the filter film.

[0009] Optionally, the filter layer includes a first filter film, a second filter film and a third filter film, the first filter film transmits red light, the second filter film transmits green light, and the third filter film transmits blue light;

[0010] There is a first target distance between the bottom wall of the groove filled with the first filter film and the photodiode layer, there is a second target distance between the bottom wall of the groove filled with the second filter film and the photodiode layer, and there is a third target distance between the bottom wall of the groove filled with the third filter film and the photodiode layer;

[0011] The first target distance is greater than the second target distance, and the second target distance is greater than the third target distance.

[0012] Optionally, the dielectric layer includes a first oxide layer, an etch stop layer, a metal layer and a second oxide layer stacked in sequence, the first oxide layer is in contact with the photodiode layer; and the bottom wall of the groove is located in the first oxide layer.

[0013] Optionally, the image sensor structure further includes:

[0014] The microlens layer is located on a side of the second oxide layer away from the photodiode layer.

[0015] Optionally, the image sensor structure further includes:

[0016] A metal wiring layer is located at a side of the photodiode layer away from the second oxide layer.

[0017] The present application also provides a method for manufacturing an image sensor structure, comprising:

[0018] Providing a substrate, the substrate comprising a photodiode layer and a dielectric layer stacked in sequence;

[0019] Etching the dielectric layer to obtain a plurality of grooves;

[0020] forming a filter layer, wherein the filter layer comprises a plurality of filter films with different wavelengths of transmitted light, and each filter film fills a corresponding groove;

[0021] The target distance between the bottom wall of each groove and the photodiode layer is different, and the target distance is determined based on the wavelength range of light allowed to pass through the filter film.

[0022] Optionally, the groove includes at least a first groove, a second groove and a third groove, a first filter film is formed in the first groove, a second filter film is formed in the second groove, and a third filter film is formed in the third groove, the first filter film transmits red light, the second filter film transmits green light, and the third filter film transmits blue light.

[0023] Optionally, the depth of the first groove is smaller than the depth of the second groove, and the depth of the second groove is smaller than the depth of the third groove.

[0024] An embodiment of the present application also provides an electronic device, comprising the above-mentioned image sensor structure.

[0025] The embodiment of the present application provides an image sensor structure, a manufacturing method and an electronic device, wherein the image sensor structure includes a photodiode layer, a dielectric layer and a filter layer, wherein the photodiode layer and the dielectric layer are stacked in sequence, and the dielectric layer includes a plurality of grooves; the filter layer includes a plurality of filter films with different wavelengths of transmitted light, and each filter film fills a corresponding groove; the target distance between the bottom wall of each groove and the photodiode layer is different, and the target distance is determined based on the wavelength range of light allowed to be transmitted by the filter film. In the embodiment of the present application, the corresponding target distance can be determined according to the filter films with different wavelengths of transmitted light, so that at the target distance, due to destructive interference between the light reflected from the surface of the dielectric layer and the light reflected from the surface of the photodiode layer, the intensity of the reflected light is greatly reduced, so that the light allowed to be transmitted by the filter film can be transmitted more into the photodiode layer, generating more photoelectrons, enhancing the quantum efficiency of the incident light, and thus improving the image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic diagram of an image sensor structure provided by an embodiment of the present application is shown;

[0028] Figure 2 A schematic diagram of an optical path of incident light provided in an embodiment of the present application is shown;

[0029] Figure 3-4 A schematic diagram showing another image sensor structure provided by an embodiment of the present application is shown;

[0030] Figure 5 A schematic diagram showing a process of a method for manufacturing an image sensor structure provided by an embodiment of the present application is shown;

[0031] Figure 6-13 A schematic diagram of another image sensor structure provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0034] Secondly, the present application is described in detail with reference to the schematic diagram. When describing the embodiments of the present application in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0035] For ease of understanding, an image sensor structure, a manufacturing method, and an electronic device provided in an embodiment of the present application are described in detail below with reference to the accompanying drawings.

[0036] refer to Figure 1 , which is a schematic diagram of an image sensor structure provided in an embodiment of the present application, the image sensor structure includes a photodiode layer 101 and a dielectric layer 102 stacked in sequence.

[0037] The incident light may be incident on the dielectric layer 102 of the image sensor structure and enter the photodiode layer 101. The photodiode layer 101 may be used to set a photodiode (PD) to convert the incident photons into photoelectrons, thereby realizing the conversion of optical signals into electrical signals. The dielectric layer 102 may include a plurality of grooves, which may be used to fill the filter film 103.

[0038] The image sensor structure may further include a filter layer, which includes a plurality of filter films with different wavelengths of transmitted light, and each filter film fills a corresponding groove. Specifically, different filter films may allow different wavelengths of light to be transmitted. For example, some filter films may allow red light to be transmitted, and some filter films may allow blue light to be transmitted. A filter film 103 may be filled in a groove, and the filter film 103 is used to transmit light consistent with the wavelength of light allowed to be transmitted by the filter film 103.

[0039] That is, the filter film 103 can be distributed in the grooves, and the filter film 103 can be formed by coating a film layer used as the filter film 103 in the grooves, and the filter film 103 in each groove can correspond to a color, and is used to allow incident light with a wavelength consistent with the color to pass through. An array formed by multiple grooves can constitute a back metal grating. Since a filter film 103 of a color is set in each groove, the back metal grating can be used to isolate blocks of different colors to prevent them from affecting each other.

[0040] In the embodiment of the present application, the target distance between the bottom wall of each groove and the photodiode layer 101 is different, and the target distance is determined based on the wavelength range of light allowed to pass through the filter film 103. Specifically, the distance between the bottom wall of the groove and the surface of the photodiode is recorded as the target distance, and the reference Figure 1 The target distance L in the figure is different because the wavelengths of light allowed to pass through the filter films 103 in different grooves are different, so the size of the target distance can be set accordingly. Figure 1 In the embodiment, there are three grooves, which respectively allow red light, green light and blue light to pass through, and their corresponding target distances L are also different.

[0041] In summary, the corresponding target distance can be determined according to different filter films. The filter film can allow monochromatic light to pass through, and part of the transmitted light will be reflected by the bottom of the groove, and the other part will be transmitted into the remaining dielectric layer 102 and reflected from the dielectric layer 102. Figure 2 As shown, it is a schematic diagram of the optical path of an incident light provided in an embodiment of the present application. When the target distance is between the bottom of the groove and the photodiode layer 101, destructive interference (i.e., destructive interference) will occur between the light R1 reflected from the surface of the dielectric layer 102 and the light R2 reflected from the surface of the photodiode layer 101, and they cancel each other out before they leave the surface.

[0042] Compared with the related art, the depth of all grooves is consistent, and the distance between the bottom of the groove and the photodiode layer 101 is equal. In the present application, for each groove, a target distance is set based on the wavelength of light. At this target distance, destructive interference can occur between the two beams of reflected light generated by the monochromatic light entering the groove, so that the intensity of the reflected light for each color of light can be reduced, and the light allowed to pass through the filter film can be transmitted more into the photodiode layer 101, generating more photoelectrons, enhancing the quantum efficiency of the incident light, and thus improving the image quality.

[0043] Among them, quantum efficiency is a key parameter to measure the capabilities of image sensors. It describes the efficiency of image sensors in converting incident photons into electrons. It is usually expressed as a percentage. The higher the value, the stronger the conversion capability of the image sensor. By enhancing quantum efficiency, image sensors can use light more effectively, thereby capturing more image details, especially in low-light environments, and can capture more subtle light changes, with better image quality.

[0044] In a possible implementation, the target distance is greater than or equal to the first distance and less than or equal to the second distance, the first distance is an integer multiple of one quarter of the minimum wavelength of light allowed to pass through the filter film 103, and the second distance is an integer multiple of one quarter of the maximum wavelength of light allowed to pass through the filter film 103.

[0045] Specifically, for the filter film, it can allow one color of light to pass through, and each color of light has a corresponding wavelength range. For example, the wavelength range corresponding to red light is 620-750nm, the wavelength range corresponding to green light is 495-570nm, the wavelength range corresponding to blue light is 450-475nm, and the wavelength range corresponding to purple light is 380-450nm.

[0046] Specifically, the target distance may be related to a quarter of the wavelength range of light that the filter film 103 allows to pass through, or may be an integer multiple thereof. The minimum wavelength of light that the filter film 103 allows to pass through may be expressed as λ1, and the maximum wavelength of light that is allowed to pass through may be expressed as λ2. N represents a positive integer, and the target distance may be expressed as:

[0047]

[0048] For example, for a groove provided with a filter film that allows red light to pass through, the corresponding target distance may be in the range of 155 nm-187.5 nm, for example, the target distance may be 162.5 nm.

[0049] In this way, by setting the target distance to be related to one-fourth of the wavelength range of light allowed to pass through the filter film, destructive interference can be ensured to occur, avoiding the situation where destructive interference cannot occur or the interference effect is poor due to insufficient or excessive target distance, thereby further reducing the intensity of the reflected light and allowing more light to be transmitted into the photodiode to generate photoelectrons and improve quantum efficiency.

[0050] In a possible implementation, the filter layer includes a first filter film, a second filter film and a third filter film, the first filter film transmits red light, the second filter film transmits green light, and the third filter film transmits blue light; there is a first target distance between the bottom wall of the groove filled with the first filter film and the photodiode layer, there is a second target distance between the bottom wall of the groove filled with the second filter film and the photodiode layer, and there is a third target distance between the bottom wall of the groove filled with the third filter film and the photodiode layer; the first target distance is greater than the second target distance, and the second target distance is greater than the third target distance.

[0051] Specifically, when the first red filter film is filled in the groove, red light can be allowed to pass through, and the distance between the bottom wall of the groove and the surface of the photodiode layer 101 can be recorded as the first target distance, when the second filter film that allows green light to pass through is filled in the groove, the distance between the bottom wall of the groove and the surface of the photodiode layer 101 can be recorded as the second target distance, and when the third filter film that allows blue light to pass through is filled in the groove, the distance between the bottom wall of the groove and the surface of the photodiode layer 101 can be recorded as the third target distance. For example, the first target distance, the second target distance, and the third target distance can be 162.5nm, 137.5nm, and 112.5nm, respectively.

[0052] By setting the first target distance, the second target distance and the third target distance to decrease in sequence, it can be ensured that the integer multiples used in calculating the three target distances are the same, for example, they are all integer multiples of twice, so that the depths of the grooves of different filter films are roughly in the same range, and the etching depth of the grooves can be ensured to be within the existing etching process window, avoiding the situation where the depth of some grooves is too deep and the target distance is too small, resulting in greater etching difficulty and inability to achieve. This ensures that all grooves can be successfully etched within the etching process window, improves the etching effect, and improves the accuracy of the target distance.

[0053] In a possible implementation, the dielectric layer 102 may include a first oxide layer 1021 , an etch stop layer 1022 , a metal layer 1023 , and a second oxide layer 1024 stacked in sequence, the first oxide layer 1021 is in contact with the photodiode layer 101 , and the bottom wall of the groove is located in the first oxide layer 1021 .

[0054] Specifically, refer to Figure 3 As shown, the image sensor includes a photodiode layer 101, a first oxide layer 1021, an etch stop layer 1022, a metal layer 1023 and a second oxide layer 1024 stacked in sequence from bottom to top, and the bottom wall of the groove can be located in the first oxide layer 1021, wherein the metal layer 1023 can ensure that the side wall of the groove has a higher reflectivity to light, so that more light can enter the bottom wall of the groove and generate more photoelectrons. The material of the metal layer 1023 can be tungsten (W), for example, and the thickness can be 200nm, for example. The etch stop layer 1022 can be used as an etching stop film layer to ensure that the first oxide layer 1021 below the etch stop layer 1022 is not etched. The etch stop layer 1022 can be TiN, for example. In this way, in the process of etching to form the groove in steps, by accurately controlling the etching stop, a more accurate groove depth can be etched to ensure the accuracy of the target distance. In summary, by configuring the oxide layer 102 to include multiple film layers, each film layer can be etched step by step, thereby being able to etch the depth of the groove more accurately.

[0055] In a possible implementation, the image sensor structure may further include a microlens layer 104 located on a side of the second oxide layer 1024 away from the photodiode layer 101, Figure 3 As shown, a microlens layer 104 may be disposed on the second oxide layer 1024 . The microlens layer 104 may include one or more microlenses. For example, a microlens may be disposed on each groove. The microlens may be, for example, a plano-convex lens.

[0056] In this way, light can directly enter the microlens layer 104, which can increase the amount of light entering, allowing more light to enter the groove, thereby increasing the amount of light transmitted into the photodiode layer 101, generating more photoelectrons, and improving image quality.

[0057] In a possible implementation, the image sensor structure may further include a metal wiring layer 105 located on a side of the photodiode layer 101 away from the second oxide layer 1024. Figure 4 As shown, a metal wiring layer 105 may be provided below the photodiode layer 101, and the metal wiring layer 105 has a large number of metal traces 1051. In this way, the image sensor formed is a back-illuminated structure, that is, light can be directly incident into the grooves. Compared with the front-illuminated structure in which the metal wiring layer 105 is provided above the photodiode layer 101, the light of the front-illuminated structure needs to pass through the metal wiring layer 105 before being captured by the photodiode. The back-illuminated structure can greatly increase the light energy incident on the photodiode. By providing grooves of different target depths in the back-illuminated structure, the light energy transmitted into the photodiode can be further increased, thereby improving the image quality.

[0058] Based on the image sensor structure provided in the above embodiment, the present application embodiment also provides a flow chart of a method for manufacturing an image sensor structure, with reference to Figure 5 As shown, the method may include the following steps.

[0059] S101, providing a substrate, wherein the substrate includes a photodiode layer and a dielectric layer stacked in sequence.

[0060] S102, etching the dielectric layer to obtain a plurality of grooves.

[0061] S103, forming a filter layer, the filter layer includes a plurality of filter films with different transmitted light wavelengths, each filter film fills a corresponding groove, and the target distance between the bottom wall of each groove and the photodiode layer is different, and the target distance is determined based on the wavelength range of light allowed to be transmitted by the filter film.

[0062] Specifically, the substrate may include a photodiode layer 101 and a dielectric layer 102 stacked in sequence, and the dielectric layer 102 may be etched to obtain a plurality of grooves, and the target distance between the bottom wall of the groove and the photodiode layer 101 may be determined based on the filter film 103 set in the groove, and further, may be determined based on the wavelength range of light allowed to pass through the filter film 103. In other words, the depths of all the grooves are not consistent, and some grooves are deeper and some grooves are shallower. After forming a groove with a target distance, a filter film 103 corresponding to the target distance may be filled in the groove to form a filter layer.

[0063] In the embodiment of the present application, the corresponding target distance can be determined according to the filter film with different wavelengths of transmitted light. Therefore, at the target distance, destructive interference will occur between the light reflected from the surface of the dielectric layer and the light reflected from the surface of the photodiode layer, thereby greatly reducing the intensity of the reflected light. As a result, the light allowed to pass through the filter film can be transmitted more into the photodiode layer, generating more photoelectrons, enhancing the quantum efficiency of the incident light, and thus improving the image quality.

[0064] Specifically, in the process of etching the dielectric layer 102 to obtain multiple grooves, in order to make the depth of the groove more accurate, etching can be performed in steps. The groove can be etched to a certain depth first, and then the groove can be further deepened according to the filter film 103 filled in the groove, so that the distance between the bottom wall of the groove and the photodiode layer 101 reaches the target distance.

[0065] The dielectric layer 102 may include a first oxide layer 1021, an etch stop layer 1022, a metal layer 1023, and a second oxide layer 1024 stacked in sequence from bottom to top. A TiN mask layer 201, an anti-reflective coating 202, and a fourth photoresist layer 2031 may be formed on the second oxide layer 1024. The fourth photoresist layer 2031 may be exposed using a photomask. The obtained structure is as shown in FIG. Figure 6 shown.

[0066] The fourth photoresist layer 2031 is used as a mask to etch the mask layer 201 and the anti-reflection coating 202 thereunder, and the fourth photoresist layer 2031 is removed. The obtained structure is as shown in FIG. Figure 7 As shown, then, the second oxide layer 1024 is further etched so that the second oxide layer 1024 also has a corresponding pattern, such as Figure 8 As shown, a plurality of grooves are formed in the second oxide layer 1024. A photoresist layer is covered inside the grooves and above the second oxide layer 1024, which is not shown in the figure, so as to perform secondary etching based on the target depth of the grooves.

[0067] Next, a photomask may be placed above the dielectric layer 102 to expose the photoresist layer in the target groove, thereby transferring the pattern of the photomask to the photoresist layer, thereby removing the photoresist layer in the target groove and retaining the photoresist layer in other grooves. The target groove may be understood as a groove that needs secondary etching to adjust the groove depth.

[0068] Next, the target groove is etched to obtain a target groove with a target depth; the target depth is the depth of the target groove in the direction from the photodiode layer 101 to the dielectric layer 102, the target depth is the difference between the thickness of the dielectric layer 102 and the target distance, the target distance is the distance between the bottom wall of the target groove and the photodiode layer 101, and the target distance is determined based on the wavelength range of light allowed to pass through the filter film 103 to be filled in the target groove.

[0069] In the embodiment of the present application, the target groove can be etched twice, and the etching amount can be controlled by adjusting the amount of etching gas, etching time and other parameters to obtain a target groove with a target depth, thereby deepening the depth of the target groove. The target distance is the distance between the bottom wall of the target groove and the surface of the photodiode layer 101, and the target distance is determined based on the wavelength range of light allowed to pass through the filter film 103 to be filled in the target groove. In other words, the target depth of the target groove is determined by the filter film 103 to be filled in the target groove, and the target depth is determined by the wavelength range of light allowed to pass through the filter film 103.

[0070] In a possible implementation, the groove may include at least a first groove, a second groove, and a third groove, a first filter film is formed in the first groove, a second filter film is formed in the second groove, and a third filter film is formed in the third groove, the first filter film transmits red light, the second filter film transmits green light, and the third filter film transmits blue light. In this way, the groove in the image sensor structure can allow red light, green light, and blue light to pass through, which can make the image display clearer and more colorful. Specifically, filling the first filter film, the second filter film, and the third filter film in the first groove, the second groove, and the third groove, respectively, can include steps S201-step S206.

[0071] S201, filling a first photoresist layer in the groove, performing an exposure process on the first photoresist layer in the first groove using a first photomask, and removing the first photoresist layer in the first groove.

[0072] Specifically, the first photoresist layer 2032 may be filled in all the grooves, and a first photomask may be disposed above the first photoresist layer 2032 to expose the first photoresist layer 2032 in the first groove, thereby removing the first photoresist layer 2032 in the first groove and retaining the first photoresist layer 2032 in other grooves to protect the other grooves. Fig. 9 , which is a schematic diagram of the structure after the first photoresist layer 2032 in the first groove is removed.

[0073] S202, etching the first groove to obtain a first target groove having a first target depth.

[0074] Specifically, the first groove can be etched a second time, and a first target depth can be determined based on the first filter film subsequently filled in the first groove. At the first target depth, destructive interference can occur between the reflected light formed by the light allowed to pass through the first groove, thereby improving the light transmission capability, thereby obtaining a first target groove with the first target depth. Fig.10 As shown, the depth of the first target groove is deepened.

[0075] S203, filling the groove with a second photoresist layer, exposing the second photoresist layer in the second groove using a second photomask, and removing the second photoresist layer in the second groove.

[0076] Specifically, the photoresist layer can be filled in all the grooves again, and the photoresist layer is recorded as the second photoresist layer 2033. The second photoresist layer 2033 in the second groove is exposed and removed by using a second mask, and the second photoresist layer 2033 in other grooves is retained. Fig.11 shown.

[0077] S204, etching the second groove to obtain a second target groove having a second target depth.

[0078] Specifically, the second groove may be etched again to obtain a second target groove having a second target depth. At the second target depth, the reflected light in the second target groove may undergo destructive interference, thereby allowing more light to be transmitted into the photodiode layer 101 to form more photoelectrons. Fig.12 As shown, the second target groove located in the middle has a second target depth.

[0079] S205, filling the groove with a third photoresist layer, exposing the third photoresist layer in the third groove using a third photomask, and removing the third photoresist layer in the third groove.

[0080] Specifically, the previous operation may be repeated to fill all the grooves with the third photoresist layer, and the third photoresist layer in the third groove is exposed and cleaned using a third photomask, thereby removing the third photoresist layer in the groove.

[0081] S206, etching the third groove to obtain a third target groove having a third target depth.

[0082] Specifically, the third groove can be etched, and parameters such as etching time and etching gas can be adjusted to obtain a third target groove, and the depth of the third target groove is the third target depth, thereby achieving the effect of improving the light transmission ability, referring to Fig.13 As shown, the three grooves from left to right are respectively the first groove, the second groove and the third groove, and their depths are respectively the first target depth, the second target depth and the third target depth.

[0083] In this way, for each color of light, the etching depth of each groove is set in sequence and in an orderly manner, thereby improving the etching efficiency and ensuring that the light transmittance can be enhanced. In addition, since the etching depth of the groove is determined by the wavelength of light allowed to pass through the filter film in the groove, the three types of masks used in the process of deepening the groove depth can directly reuse the masks used in forming the filter film 103, thereby reducing production costs and being simple and convenient.

[0084] In a possible implementation, the depth of the first groove is less than the depth of the second groove, and the depth of the second groove is less than the depth of the third groove. By setting the depths of the third groove, the second groove and the first groove to decrease in sequence, it can be ensured that the integer multiples used in calculating the depths of the three grooves are the same, for example, they are all integer multiples of two, so that the depths of the grooves with different filter films are roughly within the same range, and the etching depth of the grooves can be ensured to be within the existing etching process window, so as to avoid the difficulty of etching being too large due to the depth of some grooves being too deep and the target distance being too small, thereby ensuring that all grooves can be smoothly etched within the etching process window, improving the etching effect, and improving the accuracy of the target distance.

[0085] An embodiment of the present application also provides an electronic device that may include an image sensor structure. The electronic device may be, for example, a mobile phone, a tablet, a camera, etc., which can improve image quality.

[0086] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the method embodiment, since it is basically similar to the device embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the device embodiment.

[0087] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.

Claims

1. An image sensor structure, characterized in that: include: A photodiode layer and a dielectric layer stacked in sequence, wherein the dielectric layer comprises a plurality of grooves; A filter layer, the filter layer comprising a plurality of filter films with different wavelengths of transmitted light, each of the filter films corresponding to one of the grooves; The target distance between the bottom wall of each groove and the photodiode layer is different, and the target distance is determined based on the wavelength range of light allowed to pass through the filter film; The target distance is greater than or equal to a first distance and less than or equal to a second distance, the first distance is an integer multiple of one quarter of the minimum wavelength of light allowed to pass through the filter film, and the second distance is an integer multiple of one quarter of the maximum wavelength of light allowed to pass through the filter film.

2. The image sensor structure according to claim 1, characterized in that: The filter layer includes a first filter film, a second filter film and a third filter film, the first filter film transmits red light, the second filter film transmits green light, and the third filter film transmits blue light; There is a first target distance between the bottom wall of the groove filled with the first filter film and the photodiode layer, there is a second target distance between the bottom wall of the groove filled with the second filter film and the photodiode layer, and there is a third target distance between the bottom wall of the groove filled with the third filter film and the photodiode layer; The first target distance is greater than the second target distance, and the second target distance is greater than the third target distance.

3. The image sensor structure according to any one of claims 1 to 2, characterized in that: The dielectric layer includes a first oxide layer, an etching stop layer, a metal layer, and a second oxide layer which are stacked in sequence. The first oxide layer is in contact with the photodiode layer. The bottom wall of the groove is located in the first oxide layer.

4. The image sensor structure according to claim 3, characterized in that: The image sensor structure further includes: The microlens layer is located on a side of the second oxide layer away from the photodiode layer.

5. The image sensor structure according to claim 3, characterized in that: The image sensor structure further includes: A metal wiring layer is located at a side of the photodiode layer away from the second oxide layer.

6. A method for manufacturing an image sensor structure, characterized in that: include: Providing a substrate, the substrate comprising a photodiode layer and a dielectric layer stacked in sequence; Etching the dielectric layer to obtain a plurality of grooves; forming a filter layer, wherein the filter layer comprises a plurality of filter films with different wavelengths of transmitted light, and each filter film fills a corresponding groove; The target distance between the bottom wall of each groove and the photodiode layer is different, and the target distance is determined based on the wavelength range of light allowed to pass through the filter film; The target distance is greater than or equal to a first distance and less than or equal to a second distance, the first distance is an integer multiple of one quarter of the minimum wavelength of light allowed to pass through the filter film, and the second distance is an integer multiple of one quarter of the maximum wavelength of light allowed to pass through the filter film.

7. The method for manufacturing an image sensor structure according to claim 6, characterized in that: The grooves at least include a first groove, a second groove and a third groove, a first filter film is formed in the first groove, a second filter film is formed in the second groove, and a third filter film is formed in the third groove, the first filter film transmits red light, the second filter film transmits green light, and the third filter film transmits blue light.

8. The method for manufacturing an image sensor structure according to claim 7, characterized in that: The depth of the first groove is formed to be smaller than that of the second groove, and the depth of the second groove is formed to be smaller than that of the third groove.

9. An electronic device, characterized in that: The invention comprises the image sensor structure as described in any one of claims 1 to 5.

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