Backside illuminated photoelectric detector and manufacturing method of bonding substrate thereof

Abstract

The invention provides a backside illuminated photoelectric detector and a manufacturing method of a bonded substrate thereof, and the method comprises the steps: forming a first antireflection layer on a first surface of a first substrate, bonding the first antireflection layer with a first surface of a second substrate, and forming a functional structure of the backside illuminated photoelectric detector on a second surface of the first substrate, and removing the second substrate to expose the first antireflection layer. The functional structure is formed after the first anti-reflection layer is formed, the first anti-reflection layer can be formed in a high-temperature environment, the problems of film forming difficulty, uneven film thickness, abnormal appearance and the like caused by low-temperature growth of the first anti-reflection layer are solved, and adverse effects on the functional structure are not caused by high-temperature growth of the first anti-reflection layer; the stability of the device is improved, and the process difficulty is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for manufacturing a back-illuminated photodetector and a bonding substrate thereof. Background Art

[0002] Back-illuminated photodetectors are devices that use the photoelectric conversion effect to detect light signals. In traditional front-side illuminated (FSI) photodetectors, the incident light needs to pass through the functional structure on the front side of the substrate (including functional layers such as metal traces) to reach the photosensitive area, which causes part of the light to be blocked or absorbed. The photosensitive surface of the back-illuminated (BSI) photodetector is located on the back side of the substrate, and the light can directly shine on the photosensitive area without obstruction, reducing light loss, having higher light sensitivity and better low-light performance, and is more conducive to reducing the size of the device, which makes back-illuminated photodetectors more and more popular.

[0003] When manufacturing back-illuminated photodetectors, the front process is usually performed first to form a functional structure on the front side of the substrate, and then the front side of the substrate is bonded to a supporting substrate. The back process is then performed to form an anti-reflection film on the back side of the substrate, and then the bonding is debonded to remove the supporting substrate. This process has many disadvantages, mainly:

[0004] 1. In order to avoid damage to the functional structure at high temperature, the anti-reflection film can only be formed in a low temperature environment (such as between 200 degrees Celsius and 300 degrees Celsius), resulting in low quality of the anti-reflection film;

[0005] 2. For the same reason as above, high-temperature thermal bonding process cannot be used, so adhesive bonding technology is required. Even if the anti-reflection film is formed in a low-temperature environment, this temperature is very high for the adhesive, and the adhesive has extremely high requirements for high-temperature resistance. In addition, the vacuum film bonding equipment used for bonding requires huge investment and is costly.

[0006] 3. Front bonding also has a certain adverse effect on the front functional structure, which may cause the device dark current to be too large or the appearance to be abnormal;

[0007] 4. When the back side needs to be doped and rapidly annealed in the bulk silicon of the anti-reflection film, the front side functional structure will also be adversely affected, resulting in parameter drift and difficulty in control;

[0008] 5. The front process is usually carried out in the front-end manufacturing plant (FAB), while the front bonding process and the back thinning and anti-reflection film growth process are carried out in the back-end manufacturing plant. The contamination risk in the back-end manufacturing plant is greater and it is easy to contaminate the surface of the substrate. The semiconductor equipment in the back-end manufacturing plant is difficult to compare with the semiconductor equipment in the front-end manufacturing plant. Therefore, the processing of thin film growth, ion implantation or annealing in the back process is very difficult and the precision is not high. Summary of the invention

[0009] The object of the present invention is to provide a method for manufacturing a back-illuminated photodetector and a bonding substrate thereof, so as to solve the defects of the existing manufacturing process of the back-illuminated photodetector.

[0010] In order to achieve the above object, the present invention provides a method for manufacturing a back-illuminated photodetector bonding substrate, comprising:

[0011] forming a first anti-reflection layer on a first surface of the first substrate;

[0012] bonding the first anti-reflection layer to the first surface of the second substrate;

[0013] forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate;

[0014] The second substrate is removed to expose the first anti-reflection layer.

[0015] Optionally, before forming the first anti-reflection layer on the first surface of the first substrate, the manufacturing method further includes:

[0016] Performing ion implantation on the first substrate to form a first doped region in the first substrate, wherein the first doped region extends from a first surface of the first substrate into the first substrate;

[0017] The first substrate is annealed.

[0018] Optionally, the resistivity of the first substrate is 100Ω·cm to 10000Ω·cm.

[0019] Optionally, the first anti-reflection layer is a single layer or a stacked layer structure composed of silicon nitride, silicon oxynitride and silicon dioxide.

[0020] Optionally, a process temperature for forming the first anti-reflection layer is 600 degrees Celsius to 900 degrees Celsius.

[0021] Optionally, the first anti-reflection layer is a nanostructure, a functionalized composite structure, a double-layer structure of a high-refractive index material and a low-refractive index material, or a multi-layer structure of alternately stacked high-refractive index materials and low-refractive index materials.

[0022] Optionally, after the second substrate is removed and the first anti-reflection layer is exposed, a surface of the first anti-reflection layer has an irregular pattern.

[0023] Optionally, after bonding the first anti-reflection layer to the first surface of the second substrate, the second surface of the first substrate is ground to thin the first substrate.

[0024] The present invention also provides a method for manufacturing a back-illuminated photodetector bonded substrate, comprising:

[0025] forming a first anti-reflection layer on a first surface of the first substrate;

[0026] forming a first buffer layer on the first anti-reflection layer;

[0027] bonding the first buffer layer to the first surface of the second substrate;

[0028] forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate;

[0029] The second substrate and the first buffer layer are removed to expose the first anti-reflection layer.

[0030] Optionally, before forming the first anti-reflection layer on the first surface of the first substrate, the manufacturing method further includes:

[0031] Performing ion implantation on the first substrate to form a first doped region in the first substrate, wherein the first doped region extends from a first surface of the first substrate into the first substrate;

[0032] The first substrate is annealed.

[0033] Optionally, the resistivity of the first substrate is 100Ω·cm to 10000Ω·cm.

[0034] Optionally, the first anti-reflection layer is a single layer or a stacked layer structure composed of silicon nitride, silicon oxynitride and silicon dioxide.

[0035] Optionally, a process temperature for forming the first anti-reflection layer is 600 degrees Celsius to 900 degrees Celsius.

[0036] Optionally, the first anti-reflection layer is a nanostructure, a functionalized composite structure, a double-layer structure of a high-refractive index material and a low-refractive index material, or a multi-layer structure of alternately stacked high-refractive index materials and low-refractive index materials.

[0037] Optionally, after the second substrate and the first buffer layer are removed and the first anti-reflection layer is exposed, a surface of the first anti-reflection layer has an irregular pattern.

[0038] Optionally, the material of the first buffer layer is silicon dioxide.

[0039] Optionally, after bonding the first anti-reflection layer to the first surface of the second substrate, the second surface of the first substrate is ground to thin the first substrate.

[0040] The present invention also provides a method for manufacturing a back-illuminated photodetector bonded substrate, comprising:

[0041] forming a first anti-reflection layer on a first surface of the first substrate;

[0042] forming a second buffer layer on the first surface of the second substrate;

[0043] bonding the second buffer layer to the first anti-reflection layer;

[0044] forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate;

[0045] The second substrate is removed.

[0046] Optionally, the material of the second buffer layer is silicon dioxide.

[0047] Optionally, after removing the second substrate, the entire second buffer layer is removed to expose the first anti-reflection layer.

[0048] Optionally, after removing the second substrate, at least a portion or all of the second buffer layer is retained, and the retained portion or all of the second buffer layer serves as a second anti-reflection layer.

[0049] Optionally, before forming the first anti-reflection layer on the first surface of the first substrate, the manufacturing method further includes:

[0050] Performing ion implantation on the first substrate to form a first doped region in the first substrate, wherein the first doped region extends from a first surface of the first substrate into the first substrate;

[0051] The first substrate is annealed.

[0052] Optionally, the resistivity of the first substrate is 100Ω·cm to 10000Ω·cm.

[0053] Optionally, the first anti-reflection layer is a single layer or a stacked layer structure composed of silicon nitride, silicon oxynitride and silicon dioxide.

[0054] Optionally, a process temperature for forming the first anti-reflection layer is 600 degrees Celsius to 900 degrees Celsius.

[0055] Optionally, the first anti-reflection layer is a nanostructure, a functionalized composite structure, a double-layer structure of a high-refractive index material and a low-refractive index material, or a multi-layer structure of alternately stacked high-refractive index materials and low-refractive index materials.

[0056] Optionally, after the second substrate is removed and the first anti-reflection layer is exposed, a surface of the first anti-reflection layer has an irregular pattern.

[0057] Optionally, after bonding the second buffer layer to the first anti-reflection layer, the second surface of the first substrate is ground to thin the first substrate.

[0058] The present invention also provides a back-illuminated photoelectric detector, and its bonding substrate is manufactured by adopting the manufacturing method of the back-illuminated photoelectric detector bonding substrate.

[0059] Optionally, the surface of the first anti-reflection layer has an irregular pattern.

[0060] The present invention also provides a method for manufacturing a back-illuminated photoelectric detector, wherein the bonding substrate is manufactured by adopting the method for manufacturing the bonding substrate of the back-illuminated photoelectric detector.

[0061] Optionally, the surface of the first anti-reflection layer has an irregular pattern.

[0062] In the manufacturing method of the back-illuminated photodetector and the bonded substrate thereof provided by the present invention, a first anti-reflection layer is first formed on the first surface of the first substrate, then the first anti-reflection layer is bonded to the first surface of the second substrate, and then the functional structure of the back-illuminated photodetector is formed on the second surface of the first substrate, and then the second substrate is removed to expose the first anti-reflection layer. The present invention forms the first anti-reflection layer first and then forms the functional structure. The first anti-reflection layer can be formed in a high-temperature environment, avoiding the problems of film formation difficulty, poor film quality, uneven film thickness, abnormal appearance, etc. caused by low-temperature growth of the first anti-reflection layer, and high-temperature growth of the first anti-reflection layer will not cause adverse effects on the functional structure, thereby improving the stability of the device; and, the surface of the first anti-reflection layer is flat and serves as a bonding surface, the second substrate can provide more stable mechanical support, and the bonding process can also adopt a conventional thermal bonding process, without the need to use an adhesive bonding process and a vacuum film bonding equipment, with lower process requirements and manufacturing costs, and no adverse effects on the front device; when the back side needs to be doped and rapidly annealed in the bulk silicon of the anti-reflection film, the front functional structure will not be adversely affected; in addition, the process of forming the first anti-reflection layer, the bonding process, and the process of forming the functional structure can all be carried out in a front-end manufacturing plant, reducing the risk of contamination on the surface of the first substrate, with lower processing difficulty and higher precision, thereby improving the performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A flow chart of a method for manufacturing a back-illuminated photodetector bonding substrate provided in Embodiment 1 of the present invention;

[0064] Figure 2 to Figure 6 The schematic diagram of the structure corresponding to the corresponding steps of the method for manufacturing a back-illuminated photodetector bonding substrate provided in the first embodiment of the present invention, wherein: Figure 6 A schematic diagram of the structure of a back-illuminated photodetector provided in Embodiment 1 of the present invention;

[0065] Figure 7 A flow chart of a method for manufacturing a back-illuminated photodetector bonding substrate provided in Embodiment 1 of the present invention;

[0066] Figure 8 to Figure 12 The schematic diagram of the structure corresponding to the corresponding steps of the method for manufacturing a back-illuminated photodetector bonding substrate provided in the second embodiment of the present invention, wherein: Fig.12 A schematic diagram of the structure of a back-illuminated photodetector provided in Embodiment 2 of the present invention;

[0067] Fig.13 A flow chart of a method for manufacturing a back-illuminated photodetector bonding substrate provided in Embodiment 3 of the present invention;

[0068] Figures 14 to 19 The schematic diagram of the structure corresponding to the corresponding steps of the method for manufacturing a back-illuminated photodetector bonding substrate provided in the third embodiment of the present invention, wherein: Fig.19 A schematic diagram of the structure of a back-illuminated photodetector provided in Embodiment 3 of the present invention;

[0069] Fig. 20 A schematic diagram of the structure of a back-illuminated photodetector provided in Embodiment 4 of the present invention;

[0070] Wherein, the accompanying drawings are marked as follows:

[0071] 101-first substrate; 111-first surface of the first substrate; 121-second surface of the first substrate; 102-second substrate; 112-first surface of the second substrate; 122-second surface of the second substrate; 200-first anti-reflection layer; 301-first buffer layer; 302-second buffer layer; 401-second doping region; 402-third doping region; 403-fourth doping region; 404-first interconnection structure; 405-second interconnection structure; 406-third interconnection structure; 407-dielectric layer; 408-passivation layer. DETAILED DESCRIPTION

[0072] The specific implementation of the present invention will be described in more detail below in conjunction with the schematic diagram. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0073] Embodiment 1

[0074] Figure 1 A flow chart of a method for manufacturing a back-illuminated photodetector bonding substrate provided in this embodiment.

[0075] like Figure 1 As shown, the method for manufacturing the back-illuminated photodetector bonding substrate includes:

[0076] Step S100: forming a first anti-reflection layer on the first surface of the first substrate;

[0077] Step S200: bonding the first anti-reflection layer to the first surface of the second substrate;

[0078] Step S300: forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate; and,

[0079] Step S400: removing the second substrate and exposing the first anti-reflection layer.

[0080] Figure 2 to Figure 7 The following is a schematic diagram of the structure corresponding to the corresponding steps of the method for manufacturing a back-illuminated photodetector bonding substrate provided in this embodiment. Figure 2 to Figure 7 The method for manufacturing the back-illuminated photodetector bonding substrate provided in this embodiment is described in detail.

[0081] like Figure 2 As shown, step S100 is performed to provide the first substrate 101, wherein the first substrate 101 has a first surface 111 and a second surface 121 relative to each other. In this embodiment, the back-illuminated photodetector is a back-illuminated back-illuminated photodetector, and therefore, the first surface 111 of the first substrate 101 is its back side, and the second surface 121 of the first substrate 101 is its front side.

[0082] Optionally, the first substrate 101 may be a silicon substrate, a germanium substrate, a germanium silicon substrate or a gallium arsenide substrate, etc. In this embodiment, the first substrate 101 is an N-type high-resistance substrate with a resistivity of 100 Ω·cm to 10000 Ω·cm. The use of a high-resistance substrate can improve the photoelectric conversion efficiency of the back-illuminated photodetector, thereby improving the sensitivity of the back-illuminated photodetector.

[0083] In some embodiments, ion implantation may be performed on the first substrate 101 to form a first doped region ( Figure 2 The first doped region extends from the first surface 111 of the first substrate 101 to the inside of the first substrate 101, and then the first substrate 101 is annealed to repair the damage caused by ion implantation to the first substrate 101. The first doped region can improve the dark current and enhance the performance of the back-illuminated photodetector.

[0084] Please continue reading Figure 2 , the first anti-reflection layer 200 is formed on the first surface 111 of the first substrate 101 by a physical sputtering process, and the first anti-reflection layer 200 covers the first surface 111 of the first substrate 101. In this embodiment, the first anti-reflection layer 200 can be formed in a high temperature environment, thereby avoiding the problems of film formation difficulty, uneven film thickness, abnormal appearance, etc. caused by low temperature growth of the first anti-reflection layer 200, and improving the film quality of the first anti-reflection layer 200. For example, the first anti-reflection layer 200 can be a single layer or a stacked layer structure composed of silicon nitride, silicon oxynitride and silicon dioxide, and the process temperature for forming the first anti-reflection layer 200 can be 600 degrees Celsius to 900 degrees Celsius, but should not be limited thereto.

[0085] In the present embodiment, the material of the first anti-reflection layer 200 is at least one of silicon nitride, silicon oxynitride and silicon dioxide. The first anti-reflection layer 200 is a single layer or a stacked structure, for example, it can be a nanostructure, a functionalized composite structure, a double-layer structure in which a high refractive index material (such as TiO2, HfO2) and a low refractive index material (such as SiO2) are alternately stacked, or a high refractive index material and a low refractive index material are alternately stacked (such as TiO2 / SiO2 alternately stacked or Al2O3 / SiO2 alternately stacked, etc.).

[0086] like Figure 3 As shown, step S200 is performed to provide the second substrate 102, which can generally be a bare chip. The second substrate 102 also has a first surface 112 and a second surface 122 opposite to each other, one of which is the back surface and the other is the front surface.

[0087] The first anti-reflection layer 200 is bonded to the first surface 112 of the second substrate 102. It is understandable that the surface of the first anti-reflection layer 200 is flat and serves as a bonding surface, the second substrate 102 can provide a more stable mechanical support, and the bonding process can also adopt a conventional thermal bonding process without using a vacuum laminating device, and the process requirements and manufacturing costs are relatively low.

[0088] like Figure 4 As shown, the second surface 121 of the first substrate 101 is ground to thin the first substrate 101, and the first substrate 101 is polished. It can be understood that when the first substrate 101 is a thin sheet, the first substrate 101 does not need to be thinned.

[0089] like Figure 5 As shown, step S300 is performed to form the functional structure of the back-illuminated photodetector on the second surface 121 of the first substrate 101. In this embodiment, the functional structure is a PIN structure, and the specific steps of forming the functional structure may be:

[0090] First, ion implantation is performed on the first substrate 101 to form a second doping region 401 and a third doping region 402 in the first substrate 101, wherein the second doping region 401 and the third doping region 402 extend from the second surface 121 of the first substrate 101 into the first substrate 101. The second doping region 401 and the third doping region 402 have different conductivity types. In this embodiment, the conductivity type of the second doping region 401 is N-type, and the conductivity type of the third doping region 402 is P-type.

[0091] Next, a first dielectric layer 405 is formed on the second surface 121 of the first substrate 101 and holes are punched in the first dielectric layer 405, and a first interconnection structure 403 and a second interconnection structure 404 are formed in the first dielectric layer 405. The first interconnection structure 403 and the second interconnection structure 404 pass through the first dielectric layer 405 and are respectively connected to the second doping region 401 and the third doping region 402. In this embodiment, the first dielectric layer 405 can generally be a stacked structure composed of multiple dielectric films, the first interconnection structure 403 and the second interconnection structure 404 can include a metal layer and a plug, and the first interconnection structure 403 and the second interconnection structure 404 can be used to apply voltage to the second doping region 401 and the third doping region 402.

[0092] Afterwards, a first passivation layer 406 is formed on the first dielectric layer 405, and the first passivation layer 406 covers the first dielectric layer 405. It is understandable that, since no thin film growth, bonding and other processes are required after the first passivation layer 406 is formed, the requirements for the thickness and flatness of the first passivation layer 406 in this embodiment are not high.

[0093] It should be noted that the specific structure and manufacturing steps of the functional structure in this embodiment are only examples, and the functional structure may also be other structures for realizing photoelectric detection, which will not be illustrated one by one here.

[0094] like Figure 6 As shown, step S400 is performed to remove the second substrate 102 by a grinding process or an etching process to expose the first anti-reflection layer 200, thereby forming the back-illuminated photodetector, and the first anti-reflection layer 200 is the light incident surface of the back-illuminated photodetector. In addition, after removing the second substrate 102, the first anti-reflection layer 200 is exposed, and the surface of the first anti-reflection layer 200 has an irregular pattern, thereby improving the anti-reflection effect.

[0095] It should be noted that, in this embodiment, the process of forming the first anti-reflection layer 200, the bonding process and the process of forming the functional structure can all be carried out in the front-end manufacturing plant, reducing the risk of contamination on the surface of the first substrate 101, reducing the processing difficulty and increasing the precision, thereby improving the performance of the device.

[0096] Furthermore, if Figure 6 As shown, this embodiment also provides a back-illuminated photodetector, whose bonding substrate is manufactured by the manufacturing method of the back-illuminated photodetector bonding substrate. In addition, in this embodiment, the surface of the first anti-reflection layer 200 has an irregular pattern, and the anti-reflection effect is better.

[0097] Furthermore, this embodiment also provides a method for manufacturing a back-illuminated photodetector, wherein the bonding substrate is manufactured by the method for manufacturing a back-illuminated photodetector bonding substrate. In addition, the surface of the first anti-reflection layer 200 has an irregular pattern, and the anti-reflection effect is better.

[0098] Embodiment 2

[0099] Figure 7 A flow chart of a method for manufacturing a back-illuminated photodetector bonding substrate provided in this embodiment.

[0100] like Figure 7 As shown, the method for manufacturing the back-illuminated photodetector bonding substrate includes:

[0101] Step S100: forming a first anti-reflection layer on a first surface of a first substrate;

[0102] Step S200: forming a first buffer layer on the first anti-reflection layer;

[0103] Step S300: bonding the first buffer layer to the first surface of the second substrate;

[0104] Step S400: forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate;

[0105] Step S500: removing the second substrate and the first buffer layer and exposing the first anti-reflection layer.

[0106] Figure 8 to Figure 12 The following is a schematic diagram of the structure corresponding to the corresponding steps of the method for manufacturing a back-illuminated photodetector bonding substrate provided in this embodiment. Figure 8 to Figure 12 The method for manufacturing the back-illuminated photodetector bonding substrate provided in this embodiment is described in detail.

[0107] like Figure 8 As shown, step S100 is performed to provide the first substrate 101, wherein the first substrate 101 has a first surface 111 and a second surface 121 relative to each other. In this embodiment, the back-illuminated photodetector is a back-illuminated back-illuminated photodetector, and therefore, the first surface 111 of the first substrate 101 is its back side, and the second surface 121 of the first substrate 101 is its front side.

[0108] Optionally, the first substrate 101 may be a silicon substrate, a germanium substrate, a germanium silicon substrate or a gallium arsenide substrate, etc. In this embodiment, the first substrate 101 is an N-type high-resistance substrate with a resistivity of 100 Ω·cm to 10000 Ω·cm. The use of a high-resistance substrate can improve the photoelectric conversion efficiency of the back-illuminated photodetector, thereby improving the sensitivity of the back-illuminated photodetector.

[0109] In some embodiments, ion implantation may be performed on the first substrate 101 to form a first doped region ( Figure 8 The first doped region extends from the first surface 111 of the first substrate 101 to the inside of the first substrate 101, and then the first substrate 101 is annealed to repair the damage caused by ion implantation to the first substrate 101. The first doped region can improve the dark current and enhance the performance of the back-illuminated photodetector.

[0110] Please continue reading Figure 8 , the first anti-reflection layer 200 is formed on the first surface 111 of the first substrate 101 by a physical sputtering process, and the first anti-reflection layer 200 covers the first surface 111 of the first substrate 101. In this embodiment, the first anti-reflection layer 200 can be formed in a high temperature environment, thereby avoiding the problems of film formation difficulty, uneven film thickness, abnormal appearance, etc. caused by low temperature growth of the first anti-reflection layer 200, and improving the film quality of the first anti-reflection layer 200. For example, the process temperature for forming the first anti-reflection layer 200 can be 600 degrees Celsius to 900 degrees Celsius, but it should not be limited thereto.

[0111] Afterwards, step S200 is performed to form a first buffer layer 301 on the first anti-reflection layer 200, wherein the first buffer layer 301 covers the surface of the first anti-reflection layer 200 that is away from the first substrate 101. The first buffer layer 301 can buffer stress and prevent the first anti-reflection layer 200 from being affected by subsequent processes. In some embodiments, the step of forming the first buffer layer 301 can also be omitted.

[0112] In this embodiment, the material of the first anti-reflection layer 200 is at least one of silicon nitride, silicon oxynitride and silicon dioxide. The first anti-reflection layer 200 is a single layer or a stacked structure, for example, it can be a nanostructure, a functionalized composite structure, a double-layer structure of a high refractive index material (such as TiO2, HfO2) and a low refractive index material (such as SiO2), a high refractive index material and a low refractive index material alternately stacked structure (such as TiO2 / SiO2 alternately stacked or Al2O3 / SiO2 alternately stacked, etc.).

[0113] In this embodiment, the material of the first buffer layer 301 is silicon dioxide, but the present invention is not limited thereto.

[0114] It should be noted that when the first anti-reflection layer 200 and the first buffer layer 301 are sequentially formed on the first surface 111 of the first substrate 101, the first anti-reflection layer 200 and the first buffer layer 301 are also sequentially formed on the second surface 121 of the first substrate 101 ( Figure 8 ), but this does not affect the implementation of the present invention.

[0115] like Fig. 9 As shown, step S300 is performed to provide the second substrate 102, which can generally be a bare chip. The second substrate 102 also has a first surface 112 and a second surface 122 opposite to each other, one of which is the back surface and the other is the front surface.

[0116] The first buffer layer 301 is bonded to the first surface 112 of the second substrate 102. It is understandable that the surface of the first buffer layer 301 is flat and serves as a bonding surface, the second substrate 102 can provide a more stable mechanical support, and the bonding process can also adopt a conventional thermal bonding process without using a vacuum laminating device, and the process requirements and manufacturing costs are relatively low.

[0117] like Fig.10As shown, the second surface 121 of the first substrate 101 is ground, so as to remove the first anti-reflection layer 200 and the first buffer layer 301 formed on the second surface 121 of the first substrate 101, and the first substrate 101 is thinned and polished. It can be understood that when the first substrate 101 is a thin sheet, the first anti-reflection layer 200 and the first buffer layer 301 formed on the second surface 121 of the first substrate 101 can be removed by only using a grinding process, without thinning the first substrate 101.

[0118] like Fig.11 As shown, step S400 is performed to form the functional structure of the back-illuminated photodetector on the second surface 121 of the first substrate 101. In this embodiment, the functional structure is a PIN structure, and the specific steps of forming the functional structure may be:

[0119] First, ion implantation is performed on the first substrate 101 to form a second doping region 401 and a third doping region 402 in the first substrate 101, wherein the second doping region 401 and the third doping region 402 extend from the second surface 121 of the first substrate 101 into the first substrate 101. The second doping region 401 and the third doping region 402 have different conductivity types. In this embodiment, the conductivity type of the second doping region 401 is N-type, and the conductivity type of the third doping region 402 is P-type.

[0120] Next, a first dielectric layer 405 is formed on the second surface 121 of the first substrate 101 and holes are punched in the first dielectric layer 405, and a first interconnection structure 403 and a second interconnection structure 404 are formed in the first dielectric layer 405. The first interconnection structure 403 and the second interconnection structure 404 pass through the first dielectric layer 405 and are respectively connected to the second doping region 401 and the third doping region 402. In this embodiment, the first dielectric layer 405 can generally be a stacked structure composed of multiple dielectric films, the first interconnection structure 403 and the second interconnection structure 404 can include a metal layer and a plug, and the first interconnection structure 403 and the second interconnection structure 404 can be used to apply voltage to the second doping region 401 and the third doping region 402.

[0121] Afterwards, a first passivation layer 406 is formed on the first dielectric layer 405, and the first passivation layer 406 covers the first dielectric layer 405. It is understandable that, since no thin film growth, bonding and other processes are required after the first passivation layer 406 is formed, the requirements for the thickness and flatness of the first passivation layer 406 in this embodiment are not high.

[0122] It should be noted that the specific structure and manufacturing steps of the functional structure in this embodiment are only examples, and the functional structure may also be other structures for realizing photoelectric detection, which will not be illustrated one by one here.

[0123] like Fig.12 As shown, step S500 is performed to remove the second substrate 102 by a grinding process or an etching process to expose the first buffer layer 301 .

[0124] Afterwards, the first buffer layer 301 is removed by a grinding process or an etching process (at this time, the first buffer layer 301 is only used as a sacrificial layer), and the first anti-reflection layer 200 is exposed, so as to form the back-illuminated photodetector, and the first anti-reflection layer 200 is the light incident surface of the back-illuminated photodetector. In addition, after removing the first buffer layer 301, the first anti-reflection layer 200 is exposed, and the surface of the first anti-reflection layer 200 has an irregular pattern, so as to improve the anti-reflection effect.

[0125] In some embodiments, after removing the second substrate 102 , the first buffer layer 301 may not be removed, and at least a portion or all of the first buffer layer 301 may be retained as a second anti-reflection layer to enhance the anti-reflection effect.

[0126] It should be noted that, in this embodiment, the process of forming the first anti-reflection layer 200, the bonding process and the process of forming the functional structure can all be carried out in the front-end manufacturing plant, reducing the risk of contamination on the surface of the first substrate 101, reducing the processing difficulty and increasing the precision, thereby improving the performance of the device.

[0127] Furthermore, if Fig.12 As shown, this embodiment also provides a back-illuminated photodetector, whose bonding substrate is manufactured by the manufacturing method of the back-illuminated photodetector bonding substrate. In addition, in this embodiment, the surface of the first anti-reflection layer 200 has an irregular pattern, and the anti-reflection effect is better.

[0128] Furthermore, this embodiment also provides a method for manufacturing a back-illuminated photodetector, wherein the bonding substrate is manufactured by the method for manufacturing a back-illuminated photodetector bonding substrate. In addition, the surface of the first anti-reflection layer 200 has an irregular pattern, and the anti-reflection effect is better.

[0129] Embodiment 3

[0130] Fig.13 The flowchart of the method for manufacturing the back-illuminated photodetector bonding substrate provided in this embodiment. Fig.13 As shown, the method for manufacturing the back-illuminated photodetector bonding substrate includes:

[0131] Step S100: forming a first anti-reflection layer on a first surface of a first substrate;

[0132] Step S200: forming a second buffer layer on the first surface of the second substrate;

[0133] Step S300: bonding the second buffer layer to the first anti-reflection layer;

[0134] Step S400: forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate;

[0135] Step S500: removing the second substrate.

[0136] Figures 14 to 19 The following is a schematic diagram of the structure corresponding to the corresponding steps of the method for manufacturing a back-illuminated photodetector bonding substrate provided in this embodiment. Figures 14 to 19 The method for manufacturing the back-illuminated photodetector bonding substrate provided in this embodiment is described in detail.

[0137] like Fig.14 As shown, step S100 is performed to provide the first substrate 101, wherein the first substrate 101 has a first surface 111 and a second surface 121 relative to each other. In this embodiment, the back-illuminated photodetector is a back-illuminated back-illuminated photodetector, and therefore, the first surface 111 of the first substrate 101 is its back side, and the second surface 121 of the first substrate 101 is its front side.

[0138] Optionally, the first substrate 101 may be a silicon substrate, a germanium substrate, a germanium silicon substrate or a gallium arsenide substrate, etc. In this embodiment, the first substrate 101 is an N-type high-resistance substrate with a resistivity of 100 Ω·cm to 10000 Ω·cm. The use of a high-resistance substrate can improve the photoelectric conversion efficiency of the back-illuminated photodetector, thereby improving the sensitivity of the back-illuminated photodetector.

[0139] In some embodiments, ion implantation may be performed on the first substrate 101 to form a first doped region ( Fig.14 The first doped region extends from the first surface 111 of the first substrate 101 to the inside of the first substrate 101, and then the first substrate 101 is annealed to repair the damage caused by ion implantation to the first substrate 101. The first doped region can improve the dark current and enhance the performance of the back-illuminated photodetector.

[0140] Please continue reading Fig.14, the first anti-reflection layer 200 is formed on the first surface 111 of the first substrate 101 by a physical sputtering process, and the first anti-reflection layer 200 covers the first surface 111 of the first substrate 101. In this embodiment, the first anti-reflection layer 200 can be formed in a high temperature environment, thereby avoiding the problems of film formation difficulty, uneven film thickness, abnormal appearance, etc. caused by low temperature growth of the first anti-reflection layer 200, and improving the film quality of the first anti-reflection layer 200. For example, the process temperature for forming the first anti-reflection layer 200 can be 600 degrees Celsius to 900 degrees Celsius, but it should not be limited thereto.

[0141] like Fig.15 As shown, step S200 is performed to provide the second substrate 102, which can generally be a bare chip. The second substrate 102 also has a first surface 112 and a second surface 122 opposite to each other, one of which is the back surface and the other is the front surface.

[0142] A second buffer layer 302 is formed on the first surface 112 of the second substrate 102, and the second buffer layer 302 covers the first surface 112 of the second substrate 102. The second buffer layer 302 can buffer stress and prevent the first anti-reflection layer 200 from being affected by subsequent processes. In some embodiments, the step of forming the second buffer layer 302 can also be omitted.

[0143] In the present embodiment, the material of the first anti-reflection layer 200 is at least one of silicon nitride, silicon oxynitride and silicon dioxide. The first anti-reflection layer 200 is a single layer or a stacked structure, for example, it can be a nanostructure, a functionalized composite structure, a double-layer structure in which a high refractive index material (such as TiO2, HfO2) and a low refractive index material (such as SiO2) are alternately stacked, or a high refractive index material and a low refractive index material are alternately stacked (such as TiO2 / SiO2 alternately stacked or Al2O3 / SiO2 alternately stacked, etc.).

[0144] In this embodiment, the material of the second buffer layer 302 is silicon dioxide, but the present invention is not limited thereto.

[0145] like Fig.16 As shown, step S300 is performed to bond the second buffer layer 302 to the first anti-reflection layer 200. It can be understood that the surface of the second buffer layer 302 is flat and serves as a bonding surface, the second substrate 102 can provide a more stable mechanical support, and the bonding process can also adopt a conventional thermal bonding process without using a vacuum laminating device, and the process requirements and manufacturing costs are relatively low.

[0146] like Fig.17As shown, the second surface 121 of the first substrate 101 is ground, thereby removing the first anti-reflection layer 200 formed on the second surface 121 of the first substrate 101, and thinning the first substrate 101, and polishing the first substrate 101. It can be understood that when the first substrate 101 is a thin sheet, the first anti-reflection layer 200 formed on the second surface 121 of the first substrate 101 can be removed by only using a grinding process, without thinning the first substrate 101.

[0147] like Fig.18 As shown, step S400 is performed to form the functional structure of the back-illuminated photodetector on the second surface 121 of the first substrate 101. In this embodiment, the functional structure is a PIN structure, and the specific steps of forming the functional structure may be:

[0148] First, ion implantation is performed on the first substrate 101 to form a second doping region 401 and a third doping region 402 in the first substrate 101, wherein the second doping region 401 and the third doping region 402 extend from the second surface 121 of the first substrate 101 into the first substrate 101. The second doping region 401 and the third doping region 402 have different conductivity types. In this embodiment, the conductivity type of the second doping region 401 is N-type, and the conductivity type of the third doping region 402 is P-type.

[0149] Next, a first dielectric layer 405 is formed on the second surface 121 of the first substrate 101 and holes are punched in the first dielectric layer 405, and a first interconnection structure 403 and a second interconnection structure 404 are formed in the first dielectric layer 405. The first interconnection structure 403 and the second interconnection structure 404 pass through the first dielectric layer 405 and are respectively connected to the second doping region 401 and the third doping region 402. In this embodiment, the first dielectric layer 405 can generally be a stacked structure composed of multiple dielectric films, the first interconnection structure 403 and the second interconnection structure 404 can include a metal layer and a plug, and the first interconnection structure 403 and the second interconnection structure 404 can be used to apply voltage to the second doping region 401 and the third doping region 402.

[0150] Afterwards, a first passivation layer 406 is formed on the first dielectric layer 405, and the first passivation layer 406 covers the first dielectric layer 405. It is understandable that, since no thin film growth, bonding and other processes are required after the first passivation layer 406 is formed, the requirements for the thickness and flatness of the first passivation layer 406 in this embodiment are not high.

[0151] It should be noted that the specific structure and manufacturing steps of the functional structure in this embodiment are only examples, and the functional structure may also be other structures for realizing photoelectric detection, which will not be illustrated one by one here.

[0152] like Fig.19 As shown, step S500 is performed to remove the second substrate 102 by a grinding process or an etching process to expose the second buffer layer 302 , and the entire second buffer layer 302 is used as a second anti-reflection layer to enhance the anti-reflection effect.

[0153] In some embodiments, a grinding process or an etching process may be used to remove part of the second buffer layer 302 and retain part of the second buffer layer 302 . The retained part of the second buffer layer 302 serves as a second anti-reflection layer to enhance the anti-reflection effect.

[0154] In some embodiments, the second buffer layer 302 is completely removed by a grinding process or an etching process (in this case, the second buffer layer 302 is only used as a sacrificial layer), and the first anti-reflection layer 200 is exposed, thereby forming the back-illuminated photodetector, and the first anti-reflection layer 200 is the light incident surface of the back-illuminated photodetector. In addition, after removing the second buffer layer 302, the first anti-reflection layer 200 is exposed, and the surface of the first anti-reflection layer 200 has an irregular pattern, thereby improving the anti-reflection effect.

[0155] It should be noted that, in this embodiment, the process of forming the first anti-reflection layer 200, the bonding process and the process of forming the functional structure can all be carried out in the front-end manufacturing plant, reducing the risk of contamination on the surface of the first substrate 101, reducing the processing difficulty and increasing the precision, thereby improving the performance of the device.

[0156] Furthermore, if Fig.19 As shown, this embodiment also provides a back-illuminated photodetector, whose bonding substrate is manufactured by the manufacturing method of the back-illuminated photodetector bonding substrate. In addition, in this embodiment, the surface of the first anti-reflection layer 200 has an irregular pattern, and the anti-reflection effect is better.

[0157] Furthermore, this embodiment also provides a method for manufacturing a back-illuminated photodetector, wherein the bonding substrate is manufactured by the method for manufacturing a back-illuminated photodetector bonding substrate. In addition, the surface of the first anti-reflection layer 200 has an irregular pattern, and the anti-reflection effect is better.

[0158] Embodiment 4

[0159] Fig. 20 This is a schematic diagram of the structure of the back-illuminated photodetector provided in this embodiment. Fig. 20As shown, the difference from the first embodiment is that in this embodiment, the functional structure of the back-illuminated photodetector is a triode structure, and the functional structure of the back-illuminated photodetector can be prepared according to the following steps:

[0160] First, ion implantation is performed on the first substrate 101 to form a fourth doping region 501 (base region B), a fifth doping region 502 (emitter region E) and a sixth doping region 503 (collector region C) in the first substrate 101. The fourth doping region 501, the fifth doping region 502 and the sixth doping region 503 extend from the second surface 121 of the first substrate 101 to the inside of the first substrate 101. The fourth doping region 501 and the fifth doping region 502 and the sixth doping region 503 have different conductivity types. In this embodiment, the conductivity type of the fourth doping region 501 is N-type, and the conductivity type of the fifth doping region 502 and the sixth doping region 503 is P-type.

[0161] Next, a second dielectric layer 507 is formed on the second surface 121 of the first substrate 101 and holes are punched in the second dielectric layer 507, and a third interconnection structure 504, a fourth interconnection structure 505 and a fifth interconnection structure 506 are formed in the second dielectric layer 507. The third interconnection structure 504, the fourth interconnection structure 505 and the fifth interconnection structure 506 pass through the second dielectric layer 507 and are respectively interconnected with the fourth doping region 501, the fifth doping region 502 and the sixth doping region 503. In this embodiment, the second dielectric layer 507 can generally be a stacked structure composed of multiple dielectric films, the third interconnection structure 504, the fourth interconnection structure 505 and the fifth interconnection structure 506 can include a metal layer and a plug, and the third interconnection structure 504, the fourth interconnection structure 505 and the fifth interconnection structure 506 can be used to apply voltage to the fourth doping region 501, the fifth doping region 502 and the sixth doping region 503.

[0162] Afterwards, a second passivation layer 508 is formed on the second dielectric layer 507, and the second passivation layer 508 covers the second dielectric layer 507. It can be understood that, since no thin film growth, bonding and other processes are required after the second passivation layer 508 is formed, the present embodiment does not have high requirements on the thickness and flatness of the second passivation layer 508.

[0163] In summary, in the manufacturing method of the back-illuminated photodetector and the bonded substrate thereof provided in an embodiment of the present invention, a first anti-reflection layer is first formed on the first surface of the first substrate, and then the first anti-reflection layer is bonded to the first surface of the second substrate, and then the functional structure of the back-illuminated photodetector is formed on the second surface of the first substrate, and then the second substrate is removed to expose the first anti-reflection layer. The present invention forms the first anti-reflection layer first and then forms the functional structure. The first anti-reflection layer can be formed in a high-temperature environment, avoiding the problems of film formation difficulty, poor film quality, uneven film thickness, abnormal appearance, etc. caused by low-temperature growth of the first anti-reflection layer, and high-temperature growth of the first anti-reflection layer will not cause adverse effects on the functional structure, thereby improving the stability of the device; and, the surface of the first anti-reflection layer is flat and serves as a bonding surface, the second substrate can provide more stable mechanical support, and the bonding process can also adopt a conventional thermal bonding process, without the need to use an adhesive bonding process and a vacuum film bonding equipment, with lower process requirements and manufacturing costs, and no adverse effects on the front device; when the back side needs to be doped and rapidly annealed in the bulk silicon of the anti-reflection film, the front functional structure will not be adversely affected; in addition, the process of forming the first anti-reflection layer, the bonding process, and the process of forming the functional structure can all be carried out in a front-end manufacturing plant, reducing the risk of contamination on the surface of the first substrate, with lower processing difficulty and higher precision, thereby improving the performance of the device.

[0164] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0165] It should also be noted that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

[0166] It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are merely used to distinguish between the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0167] It should also be recognized that the terms described herein are only used to describe specific embodiments and are not intended to limit the scope of the invention. It should be noted that the singular forms "a" and "an" used herein and in the appended claims include plural references unless the context clearly indicates otherwise. For example, a reference to "a step" or "a device" means a reference to one or more steps or devices, and may include secondary steps and secondary devices. All conjunctions used should be understood in the broadest sense. And, the word "or" should be understood to have the definition of a logical "or", rather than a logical "exclusive or", unless the context clearly indicates otherwise. In addition, the implementation of the method and / or device in the embodiments of the present invention may include performing the selected task manually, automatically, or in combination.

Claims

1. A method for manufacturing a back-illuminated photodetector bonding substrate, characterized in that: include: forming a first anti-reflection layer on a first surface of the first substrate; bonding the first anti-reflection layer to the first surface of the second substrate; forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate; The second substrate is removed to expose the first anti-reflection layer.

2. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 1, characterized in that: Before forming the first anti-reflection layer on the first surface of the first substrate, the manufacturing method further includes: Performing ion implantation on the first substrate to form a first doped region in the first substrate, wherein the first doped region extends from a first surface of the first substrate into the first substrate; The first substrate is annealed.

3. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 1, characterized in that: The resistivity of the first substrate is 100 Ω·cm to 10000 Ω·cm.

4. The method for manufacturing a back-illuminated photodetector bonding substrate as claimed in claim 1, characterized in that: The first anti-reflection layer is a single layer or a stacked layer structure composed of silicon nitride, silicon oxynitride and silicon dioxide.

5. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 1 or 4, characterized in that: The process temperature for forming the first anti-reflection layer is 600 degrees Celsius to 900 degrees Celsius.

6. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 1, characterized in that: The first anti-reflection layer is a nanostructure, a functionalized composite structure, a double-layer structure of a high-refractive index material and a low-refractive index material, or a multi-layer structure of alternately stacked high-refractive index materials and low-refractive index materials.

7. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 1, characterized in that: After the second substrate is removed and the first anti-reflection layer is exposed, a surface of the first anti-reflection layer has an irregular pattern.

8. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 1, characterized in that: After bonding the first anti-reflection layer to the first surface of the second substrate, grinding the second surface of the first substrate to thin the first substrate.

9. A method for manufacturing a back-illuminated photodetector bonding substrate, characterized in that: include: forming a first anti-reflection layer on a first surface of the first substrate; forming a first buffer layer on the first anti-reflection layer; bonding the first buffer layer to the first surface of the second substrate; forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate; The second substrate and the first buffer layer are removed to expose the first anti-reflection layer.

10. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 9, characterized in that: Before forming the first anti-reflection layer on the first surface of the first substrate, the manufacturing method further includes: Performing ion implantation on the first substrate to form a first doped region in the first substrate, wherein the first doped region extends from a first surface of the first substrate into the first substrate; The first substrate is annealed.

11. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 9, characterized in that: The resistivity of the first substrate is 100 Ω·cm to 10000 Ω·cm.

12. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 9, characterized in that: The first anti-reflection layer is a single layer or a stacked layer structure composed of silicon nitride, silicon oxynitride and silicon dioxide.

13. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 9 or 12, characterized in that: The process temperature for forming the first anti-reflection layer is 600 degrees Celsius to 900 degrees Celsius.

14. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 9, characterized in that: The first anti-reflection layer is a nanostructure, a functionalized composite structure, a double-layer structure of a high-refractive index material and a low-refractive index material, or a multi-layer structure of alternately stacked high-refractive index materials and low-refractive index materials.

15. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 9, characterized in that: After the second substrate and the first buffer layer are removed and the first anti-reflection layer is exposed, a surface of the first anti-reflection layer has an irregular pattern.

16. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 9, characterized in that: The material of the first buffer layer is silicon dioxide.

17. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 9, characterized in that: After bonding the first anti-reflection layer to the first surface of the second substrate, grinding the second surface of the first substrate to thin the first substrate.

18. A method for manufacturing a back-illuminated photodetector bonded substrate, characterized in that: include: forming a first anti-reflection layer on a first surface of the first substrate; forming a second buffer layer on the first surface of the second substrate; bonding the second buffer layer to the first anti-reflection layer; forming a functional structure of the back-illuminated photodetector on the second surface of the first substrate; The second substrate is removed.

19. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 18, characterized in that: The material of the second buffer layer is silicon dioxide.

20. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 18, wherein: After removing the second substrate, the entire second buffer layer is removed to expose the first anti-reflection layer.

21. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 18, characterized in that: After removing the second substrate, at least a portion or all of the second buffer layer is retained, and the retained portion or all of the second buffer layer serves as a second anti-reflection layer.

22. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 18, characterized in that: Before forming the first anti-reflection layer on the first surface of the first substrate, the manufacturing method further includes: Performing ion implantation on the first substrate to form a first doped region in the first substrate, wherein the first doped region extends from a first surface of the first substrate into the first substrate; The first substrate is annealed.

23. The method for manufacturing a back-illuminated photodetector bonded substrate according to claim 18, characterized in that: The resistivity of the first substrate is 100 Ω·cm to 10000 Ω·cm.

24. The method for manufacturing a back-illuminated photodetector bonded substrate as claimed in claim 18, characterized in that: The first anti-reflection layer is a single layer or a stacked layer structure composed of silicon nitride, silicon oxynitride and silicon dioxide.

25. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 18 or 24, characterized in that: The process temperature for forming the first anti-reflection layer is 600 degrees Celsius to 900 degrees Celsius.

26. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 18, characterized in that: The first anti-reflection layer is a nanostructure, a functionalized composite structure, a double-layer structure of a high-refractive index material and a low-refractive index material, or a multi-layer structure of alternately stacked high-refractive index materials and low-refractive index materials.

27. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 18, characterized in that: After the second substrate is removed and the first anti-reflection layer is exposed, a surface of the first anti-reflection layer has an irregular pattern.

28. The method for manufacturing a back-illuminated photodetector bonding substrate according to claim 18, characterized in that: After bonding the second buffer layer to the first anti-reflection layer, grinding the second surface of the first substrate to thin the first substrate.

29. A back-illuminated photodetector, characterized in that: The bonding substrate is manufactured by the method for manufacturing a back-illuminated photodetector bonding substrate as claimed in any one of claims 1 to 28.

30. The back-illuminated photodetector of claim 29, wherein: The surface of the first anti-reflection layer has an irregular pattern.

31. A method for manufacturing a back-illuminated photodetector, characterized in that: The bonding substrate is manufactured by the method for manufacturing a back-illuminated photodetector bonding substrate as claimed in any one of claims 1 to 28.

32. The method for manufacturing a back-illuminated photodetector according to claim 32, wherein: The surface of the first anti-reflection layer has an irregular pattern.

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