image sensor

Abstract

An image sensor includes a semiconductor substrate, a first isolation structure, a visible light detection structure, and an infrared light detection structure. The semiconductor substrate has a first surface and a second surface opposite in a vertical direction. The first isolation structure is disposed in the semiconductor substrate to define a plurality of pixel regions in the semiconductor substrate. The visible light detection structure and the infrared light detection structure are disposed within a same pixel region, and a first portion of the visible light detection structure is disposed between the infrared light detection structure and the second surface of the semiconductor substrate in the vertical direction.

Description

TECHNICAL FIELD

[0001] The present application relates to an image sensor, and more particularly to an image sensor having a visible light detection structure and an infrared light detection structure. BACKGROUND

[0002] With the development of computer and communication industries, there is an increasing demand for high-efficiency image sensors. Image sensors can be applied in various fields, such as digital cameras, camcorders, personal communication systems, game elements, monitors, medical micro-cameras, robots, etc.

[0003] In an image sensor, in addition to visible light detection elements for receiving visible light and converting it into corresponding image signals, light detection elements corresponding to other wavelength ranges can also be provided to provide image extraction and other additional functions, such as sensing distance or / and depth for applications in 3D images, augmented reality (AR), etc. Therefore, how to improve the light sensitivity and quantum efficiency (QE) of light detection elements corresponding to visible light and other wavelength ranges in an image sensor through structural, material or / and manufacturing process design is a direction of continuous research for people in the field. SUMMARY

[0004] The present application provides an image sensor, which utilizes a visible light detection structure and an infrared light detection structure disposed in the same pixel region, thereby improving the light sensitivity, quantum efficiency or / and other related characteristics of the image sensor.

[0005] An embodiment of the present application provides an image sensor, which includes a semiconductor substrate, a first isolation structure, at least one visible light detection structure, and at least one infrared light detection structure. The semiconductor substrate has a first surface and a second surface opposite to each other in a vertical direction. The first isolation structure is disposed in the semiconductor substrate to define a plurality of pixel regions in the semiconductor substrate. The visible light detection structure and the infrared light detection structure are disposed in the semiconductor substrate and within one of the plurality of pixel regions. A first portion of the visible light detection structure is disposed between the infrared light detection structure and the second surface of the semiconductor substrate in the vertical direction. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 FIG. 1 is a schematic diagram of an image sensor according to a first embodiment of the present application;

[0007] Figure 2 FIG. 2 is a schematic diagram of an infrared light detection structure according to an embodiment of the present application;

[0008] Figure 3 Circuit diagram of an image sensor for one pixel region according to an embodiment of the present application;

[0009] Figures 4 to 9 Manufacturing method of an image sensor according to an embodiment of the present application;

[0010] Figure 5 Manufacturing method of an image sensor according to an embodiment of the present application; Figure 4 Manufacturing method of an image sensor according to an embodiment of the present application;

[0011] Figure 6 Manufacturing method of an image sensor according to an embodiment of the present application; Figure 5 Manufacturing method of an image sensor according to an embodiment of the present application;

[0012] Figure 7 Manufacturing method of an image sensor according to an embodiment of the present application; Figure 6 Manufacturing method of an image sensor according to an embodiment of the present application;

[0013] Figure 8 Manufacturing method of an image sensor according to an embodiment of the present application; Figure 7 Manufacturing method of an image sensor according to an embodiment of the present application; and

[0014] Figure 9 Manufacturing method of an image sensor according to an embodiment of the present application; Figure 8 Manufacturing method of an image sensor according to an embodiment of the present application;

[0015] Figure 10 Schematic diagram of an image sensor according to a second embodiment of the present application.

[0016] Explanation of main component symbols

[0017] 10 semiconductor substrate

[0018] 11 doped epitaxial layer

[0019] 12 intrinsic epitaxial layer

[0020] 13 doped epitaxial layer

[0021] 14 doped region

[0022] 15 patterned insulating layer

[0023] 16 conductive layer

[0024] 20 first isolation structure

[0025] 22 second isolation structure

[0026] 30 reflective structure

[0027] 32 contact structure

[0028] 34 contact structure

[0029] 36 reflective layer

[0030] 40 interconnect structure

[0031] 50 dielectric layer

[0032] 60 antireflection layer

[0033] 62 patterned isolation structure

[0034] 70 color filter unit

[0035] 70A first color filter unit

[0036] 70B second color filter unit

[0037] 70C third color filter unit

[0038] 80 microlens

[0039] 90 epitaxial fabrication process

[0040] 101 image sensor

[0041] 102 image sensor

[0042] D1 first direction

[0043] D2 second direction

[0044] DR doped region

[0045] ES epitaxial structure

[0046] G1 first gate

[0047] G2 second gate

[0048] L1 length

[0049] L2 length

[0050] L3 length

[0051] P1 first portion

[0052] P2 second portion

[0053] PD1 infrared light detection structure

[0054] PD2 visible light detection structure

[0055] PX pixel region

[0056] PX1 first pixel region

[0057] PX2 second pixel region

[0058] PX3 third pixel region

[0059] S1 first surface

[0060] S2 second surface

[0061] T1 transistor

[0062] T2 transistor

[0063] T3 transistor

[0064] T4 transistor

[0065] T5 transistor

[0066] TR trench DETAILED DESCRIPTION

[0067] The following detailed description of the application discloses sufficient information to enable those skilled in the art to practice the application. The embodiments set forth in the following description thereof, particularly when considered in conjunction with the accompanying drawings, are intended to be illustrative and not restrictive. One skilled in the art can readily devise variations and modifications without departing from the spirit and scope of the application.

[0068] Before further description of the embodiments, certain terms employed in the specification, the claims and the drawings are first explained.

[0069] The terms "on," "over," and "above" are to be interpreted in the broadest context to mean not only "directly on" something but also to include the meaning of being on something with other intervening features or layers therebetween, and not only "over" or "above" something but also to include the meaning of being "over" or "above" something without other intervening features or layers therebetween (i.e., directly on something).

[0070] The use of ordinal terms such as "first," "second," etc., in the specification and claims to modify an element of the application does not in itself connote any priority or order of one element to another, or to the process disclosed, but rather the use of such terms is merely intended to identify and distinguish a referenced element from another. Unless otherwise indicated, the use of relational terms, if any, such as "attached," "connected," "interconnected," and "positioned" and the like, are used solely to describe the relative location of the elements as illustrated, not that the elements are necessarily oriented in that manner.

[0071] The terms "forming" or "depositing" are used hereinafter to describe the act of applying a layer of material to a substrate. These terms are intended to describe any workable layer forming technique, including but not limited to thermal growth, sputtering, evaporation, chemical vapor deposition, epitaxial growth, electroplating, etc.

[0072] Reference is made to Figure 1 . Reference is made to Figure 1 A schematic diagram of an image sensor 101 is shown as a first embodiment of the present application. As shown inFigure 1 As shown, the image sensor 101 includes a semiconductor substrate 10, a first isolation structure 20, at least one infrared light detecting structure PD1, and at least one visible light detecting structure PD2. The semiconductor substrate 10 has a first surface S1 and a second surface S2 opposite to each other in a vertical direction (e.g., a first direction D1 as shown in FIG. 1). The first isolation structure 20 is disposed in the semiconductor substrate 10 for defining a plurality of pixel regions PX in the semiconductor substrate 10. The visible light detecting structure PD2 and the infrared light detecting structure PD1 are disposed in the semiconductor substrate 10 and within one of the plurality of pixel regions PX. A first portion P1 of the visible light detecting structure PD2 is disposed between the infrared light detecting structure PD1 and the second surface S2 of the semiconductor substrate 10 in the first direction D1. Figure 1 In other words, the infrared light detecting structure PD1 and the visible light detecting structure PD2 can be disposed in the same semiconductor substrate 10 and within the same pixel region PX, and a portion of the visible light detecting structure PD2 can overlap with the infrared light detecting structure PD1 in the first direction D1, thereby improving the light sensitivity or / and quantum efficiency (QE) of the infrared light detecting structure PD1 under the condition that the size of the pixel region PX is limited (e.g., under the condition that the size of each pixel region PX is relatively reduced for improving the overall resolution of the image sensor 101).

[0073] In some embodiments, the first direction D1 can be regarded as the thickness direction of the semiconductor substrate 10, the second surface S2 can be regarded as the light-incoming surface or the side facing the light source, and the first surface S1 can be regarded as the side facing away from the light source. The horizontal direction (e.g., a second direction D2 as shown in FIG. 1) orthogonal to the first direction D1 can be substantially parallel to the first surface S1 or / and the second surface S2 of the semiconductor substrate 10, but is not limited thereto. In the image sensor 101, each pixel region PX can be surrounded by the first isolation structure 20 in the horizontal direction (e.g., the second direction D2 as described above and other directions orthogonal to the first direction D1). In some embodiments, the image sensor 101 can include a plurality of infrared light detecting structures PD1 and a plurality of visible light detecting structures PD2, and the infrared light detecting structure PD1 and the visible light detecting structure PD2 can be disposed in at least one pixel region PX simultaneously. For example, in some embodiments, one infrared light detecting structure PD1 and one visible light detecting structure PD2 can be disposed in each pixel region PX, and at least part of the pixel regions PX can correspond to detecting visible light of different colors, but are not limited thereto.

[0074] In some embodiments, the first direction D1 can be regarded as the thickness direction of the semiconductor substrate 10, the second surface S2 can be regarded as the light-incoming surface or the side facing the light source, and the first surface S1 can be regarded as the side facing away from the light source. The horizontal direction (e.g., a second direction D2 as shown in FIG. 1) orthogonal to the first direction D1 can be substantially parallel to the first surface S1 or / and the second surface S2 of the semiconductor substrate 10, but is not limited thereto. In the image sensor 101, each pixel region PX can be surrounded by the first isolation structure 20 in the horizontal direction (e.g., the second direction D2 as described above and other directions orthogonal to the first direction D1). In some embodiments, the image sensor 101 can include a plurality of infrared light detecting structures PD1 and a plurality of visible light detecting structures PD2, and the infrared light detecting structure PD1 and the visible light detecting structure PD2 can be disposed in at least one pixel region PX simultaneously. For example, in some embodiments, one infrared light detecting structure PD1 and one visible light detecting structure PD2 can be disposed in each pixel region PX, and at least part of the pixel regions PX can correspond to detecting visible light of different colors, but are not limited thereto. Figure 1

[0075] ​In some embodiments, the visible light detection structure PD2 can include a visible light photodiode or a portion of a visible light photodiode, and the infrared light detection structure PD1 can include an infrared light photodiode or a portion of an infrared light photodiode, but the disclosure is not limited thereto. In some embodiments, the infrared light detection structure PD1 can also include structures other than a photodiode that can be used to convert infrared light into corresponding electronic signals, and the visible light detection structure PD2 can also include structures other than a photodiode that can be used to convert visible light into corresponding electronic signals. In addition, in some embodiments, the material composition of the infrared light detection structure PD1 can be different from the material composition of the visible light detection structure PD2, thereby improving the photosensitivity or / and QE of the infrared light detection structure PD1.

[0076] For example, the infrared light detection structure PD1 can include an epitaxial structure ES disposed in the semiconductor substrate 10, and the visible light detection structure PD2 can include a doped region DR located in the semiconductor substrate 10, but the disclosure is not limited thereto. In some embodiments, the semiconductor substrate 10 can include a silicon substrate, a silicon-containing substrate, or a substrate formed of other suitable semiconductor materials, and the doped region DR can be formed by a doping fabrication process (e.g., an ion implantation fabrication process or other suitable doping methods) performed on the semiconductor substrate 10, so the doped region DR can include a portion (e.g., silicon) of the semiconductor substrate 10 and dopants implanted in the semiconductor substrate 10 by the above-mentioned doping fabrication process. In other words, the visible light detection structure PD2 can include the same material (e.g., silicon) as the semiconductor substrate 10, and this material can be different from the material of the epitaxial structure ES. In addition, in some embodiments, the epitaxial structure ES can include epitaxial germanium, a III-V semiconductor epitaxial material (e.g., epitaxial indium gallium arsenide, InGaAs), or other materials having a higher infrared light absorption rate than the material of the semiconductor substrate 10. Therefore, although the infrared light detection structure PD1 and the visible light detection structure PD2 are disposed in the same semiconductor substrate 10 and located within the same pixel region PX, and the first portion P1 of the visible light detection structure PD2 overlaps the infrared light detection structure PD1 in the first direction D1 and is located between the light-incoming surface (e.g., the second surface S2) and the infrared light detection structure PD1, forming the infrared light detection structure PD1 with an epitaxial material having a relatively high infrared light absorption rate can improve the photosensitivity or / and QE of the infrared light detection structure PD1, so that the infrared light detection structure PD1 in the image sensor 101 can have good photoelectric conversion performance.

[0077] In some embodiments, the image sensor 101 can further include a second isolation structure 22 disposed in the semiconductor substrate 10 and located in each pixel region PX, but the application is not limited thereto. In some embodiments, a second portion P2 of the visible light detection structure PD2 can be disposed between the first isolation structure 20 and the infrared light detection structure PD1 located in the same pixel region PX in the horizontal direction (e.g., the second direction D2), the second portion P2 of the visible light detection structure PD2 can extend along the first direction D1 toward the first surface S1, and the second portion P2 of the visible light detection structure PD2 can be directly connected to the first portion P1, but the application is not limited thereto. In addition, in at least one pixel region PX, a portion of the second isolation structure 22 can be disposed between the infrared light detection structure PD1 and the second portion P2 of the visible light detection structure PD2 in the second direction D2, thereby reducing the mutual interference between the infrared light detection structure PD1 and the visible light detection structure PD2 in the same pixel region PX. In some embodiments, the first isolation structure 20 and the second isolation structure 22 can each include a single layer or multiple layers of insulating material, such as silicon oxide, silicon nitride, or other suitable insulating material.

[0078] In some embodiments, a portion of the first isolation structure 20 can extend through the semiconductor substrate 10 in the first direction D1, and the first portion P1 of the visible light detection structure PD2 can be disposed between the second isolation structure 22 and the second surface S2 of the semiconductor substrate 10 in the first direction D1, but the application is not limited thereto. In some embodiments, the length of the second isolation structure 22 in the first direction D1 can be greater than or equal to the length of the infrared light detection structure PD1 in the first direction D1, and the length of the second isolation structure 22 in the first direction D1 can be less than the length of the first isolation structure 20 in the first direction, thereby reducing the mutual interference between the infrared light detection structure PD1 and the visible light detection structure PD2 in the same pixel region PX in the second direction D2 using the second isolation structure 22 and avoiding the second isolation structure 22 extending to the visible light detection structure PD2 to negatively affect the visible light detection structure PD2.

[0079] In some embodiments, the image sensor 101 can further include at least one first gate G1, at least one second gate G2, a reflective structure 30, at least one contact structure 32, at least one contact structure 34, at least one reflective layer 36, an interconnection structure 40, and a dielectric layer 50, but the disclosure is not limited thereto. The first gate G1, the second gate G2, the reflective structure 30, the contact structure 32, the contact structure 34, the reflective layer 36, the interconnection structure 40, and the dielectric layer 50 can all be disposed on the first surface S1 of the semiconductor substrate 10. In some embodiments, the first gate G1 can be disposed corresponding to the infrared light detecting structure PD1, the second gate G2 can be disposed corresponding to the visible light detecting structure PD2, the first gate G1 can be a gate in a transistor (not shown) electrically connected to the infrared light detecting structure PD1, and the second gate G2 can be a gate in a transistor (not shown) electrically connected to the visible light detecting structure PD2, but the disclosure is not limited thereto. Figure 1 Figure 1

[0080] In some embodiments, the reflective structure 30 can be an electrically floating conductive structure, that is, the reflective structure 30 can not be electrically connected to other components, a portion of the reflective structure 30 can be disposed on the first isolation structure 20 in the first direction D1, and another portion of the reflective structure 30 can be disposed between the first gate G1 and the second gate G2, to reduce light interference between adjacent pixel regions PX and / or between the infrared light detecting structure PD1 and the visible light detecting structure PD2 in the same pixel region PX, and / or to increase the photosensitivity of the infrared light detecting structure PD1, but the disclosure is not limited thereto. In addition, in some embodiments, when the image sensor 101 is viewed in the first direction D1 (for example, when the image sensor 101 is viewed from the side of the second surface S2), the reflective structure 30 disposed between the first gate G1 and the second gate G2 can be disposed on the second isolation structure 22 in the first direction D1 and at least partially overlap the second isolation structure 22 in the first direction D1, so that the reflective structure 30 can not be in direct contact with the semiconductor substrate 10 to reduce the electrical effect of the reflective structure 30 on the infrared light detecting structure PD1 and the visible light detecting structure PD2.

[0081] ​​In some embodiments, the contact structure 32 can be disposed on and electrically connected to the first gate G1, and the contact structure 34 can be disposed on and electrically connected to the second gate G2. The reflective structure 30, the contact structure 32, and the contact structure 34 can be formed by the same fabrication process to simplify the fabrication process, and thus the reflective structure 30, the contact structure 32, and the contact structure 34 can have the same material composition, but the application is not limited thereto. In some embodiments, the reflective layer 36 can be disposed corresponding to the infrared light detecting structure PD1 in the first direction D1. Thus, the infrared light detecting structure PD1 can be disposed between the reflective layer 36 and the first portion P1 of the visible light detecting structure PD2 in the first direction D1, and the first gate G1 can be located between the infrared light detecting structure PD1 and the reflective layer 36 in the first direction D1, but the application is not limited thereto. In addition, the reflective layer 36 and at least a portion of the interconnection structure 40 can be formed by the same fabrication process to simplify the fabrication process, and thus the reflective layer 36 and at least a portion of the interconnection structure 40 can have the same material composition, but the application is not limited thereto. In some embodiments, the reflective layer 36 can be an electrically floating conductive layer, thereby reducing the negative effect of the reflective layer 36 having a relatively large range on the electrical properties of other elements (e.g., the transistor corresponding to the first gate G1 or / and the transistor corresponding to the second gate G2), but the application is not limited thereto.

[0082] In some embodiments, the image sensor 101 can include a plurality of first gates G1, a plurality of second gates G2, and a plurality of reflective layers 36 corresponding to each pixel region PX, but the application is not limited thereto. The first gate G1 and the second gate G2 described above can include a non-metallic conductive material (e.g., doped polysilicon) or a metallic conductive material, such as a metal gate structure stacked by a work function layer and a low-resistance layer, but the application is not limited thereto. The reflective structure 30, the contact structure 32, the contact structure 34, the reflective layer 36, and the interconnection structure 40 described above can include a barrier layer (not shown) and a conductive material (not shown) on the barrier layer, but the application is not limited thereto. The barrier layer described above can include titanium nitride, tantalum nitride, or other suitable barrier materials, and the conductive material described above can include a material with a relatively low resistivity, such as tungsten, aluminum, copper, titanium aluminum, titanium, etc., but the application is not limited thereto. In addition, the dielectric layer 50 can include a high-k dielectric material or other suitable dielectric materials (e.g., silicon oxide).

[0083] In some embodiments, the image sensor 101 can further include an anti-reflective layer 60, a patterned isolation structure 62, a plurality of color filter units 70, and a plurality of microlenses 80, but the disclosure is not limited thereto. The anti-reflective layer 60, the patterned isolation structure 62, the color filter units 70, and the microlenses 80 can all be disposed on the second surface S2 of the semiconductor substrate 10. The color filter units 70 and the patterned isolation structure 62 can be disposed on the anti-reflective layer 60, and the microlenses 80 can be disposed on the color filter units 70. In some embodiments, the patterned isolation structure 62 can be located between adjacent color filter units 70 to reduce light interference between adjacent color filter units 70, and the patterned isolation structure 62 can include a metal material or other material having a relatively high optical density (OD).

[0084] Each color filter unit 70 can be disposed corresponding to one of the plurality of pixel regions PX in the first direction D1. For example, in some embodiments, the color filter units 70 can include first color filter units 70A, second color filter units 70B, and third color filter units 70C of different colors disposed adjacent to each other, and the pixel regions PX can include first pixel regions PX1, second pixel regions PX2, and third pixel regions PX3 disposed corresponding to the first color filter units 70A, the second color filter units 70B, and the third color filter units 70C, respectively. Therefore, in some embodiments, the pixel regions PX corresponding to different color light can each be provided with the infrared light detection structure PD1, thereby increasing the number of infrared light detection structures PD1 provided in the image sensor 101 or / and improving the contrast or / and sharpness of the image information generated by the pixel regions PX corresponding to different colors.

[0085] Please refer to Figure 2 with Figure 1 . Figure 2 The schematic diagram of the infrared light detection structure PD1 shown is an embodiment of the present disclosure. As Figure 2 with Figure 1In some embodiments, the infrared light detecting structure PD1 can include an epitaxial structure ES formed by a doped epitaxial layer 11, an intrinsic epitaxial layer 12, and a doped epitaxial layer 13. The doped epitaxial layer 11 and the doped epitaxial layer 13 can be a p-type doped epitaxial layer (e.g., a p-type heavily doped epitaxial germanium layer) and an n-type doped epitaxial layer (e.g., an n-type heavily doped epitaxial germanium layer), respectively, thereby forming a PIN photodiode with the intrinsic epitaxial layer 12 (e.g., an intrinsic epitaxial germanium layer), but the present application is not limited thereto. In some embodiments, a doped region 14 (e.g., a p-type lightly doped epitaxial germanium region) can surround the doped epitaxial layer 13, a patterned insulating layer 15 can be disposed on the doped region 14 and the doped epitaxial layer 13, and a conductive layer 16 can be in contact with the doped epitaxial layer 13 to form an electrical connection, but the present application is not limited thereto. In some embodiments, the conductive layer 16 can be used to electrically connect the above-mentioned PIN photodiode and a transistor corresponding to the above-mentioned first gate G1, and the doped region 14 can be used to reduce the negative impact of interface defects between the doped epitaxial layer 13 and the patterned insulating layer 15 on the electrical properties of the PIN photodiode, but the present application is not limited thereto. It should be noted that the structure of the infrared light detecting structure PD1 of the present application is not limited to the above-mentioned structure, and other suitable structure designs of the infrared light detecting structure PD1 can be used according to design needs. Figure 2 The above-mentioned structure is not limited thereto, and other suitable structure designs of the infrared light detecting structure PD1 can be used according to design needs.

[0086] Please refer to Figure 3 and Figure 1 . Figure 3 The circuit schematic diagram of the image sensor corresponding to a pixel region PX in an embodiment of the present application is shown. As Figure 3 and Figure 1In some embodiments, the circuit structure corresponding to one pixel region PX can include an infrared light detecting structure PD1, a visible light detecting structure PD2, a transistor T1, a transistor T2, a transistor T3, a transistor T4, and a transistor T5, but the present application is not limited thereto. In some embodiments, one source / drain terminal of the transistor T1 can be electrically connected to the infrared light detecting structure PD1, and the other source / drain terminal of the transistor T1 can be electrically connected to one source / drain terminal of the transistor T3 and one source / drain terminal of the transistor T4, and the first gate G1 can be a gate of the transistor T1, but the present application is not limited thereto. In addition, one source / drain terminal of the transistor T2 can be electrically connected to the visible light detecting structure PD2, and the other source / drain terminal of the transistor T2 can be electrically connected to the other source / drain terminal of the transistor T3 and a gate of the transistor T5, and the second gate G2 can be a gate of the transistor T2, but the present application is not limited thereto. In some embodiments, the transistor T3 can be regarded as a switch transistor, the other source / drain terminal of the transistor T4 can be connected to a reset signal source, so the transistor T4 can be regarded as a reset transistor, and the transistor T5 can be regarded as a read transistor, but the present application is not limited thereto. It is worth mentioning that the circuit structure corresponding to the pixel region PX in the present application is not limited to the above-mentioned condition and can have other suitable circuit structures according to design needs. Figure 3 The circuit structure corresponding to the pixel region PX in the present application is not limited to the above-mentioned condition and can have other suitable circuit structures according to design needs.

[0087] Please refer to Figures 4 to 9 and Figure 1 . Figures 4 to 9 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 5 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 4 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 6 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 5 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 7 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 6 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 8 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 7 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 9 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 8 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 1 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 9 The manufacturing method of the image sensor is shown in the schematic diagram of the manufacturing method of the image sensor of one embodiment of the present application. Figure 1As shown, the method of fabricating the image sensor 101 of the present embodiment can include the following steps. At least one infrared light detecting structure PD1 is formed in the semiconductor substrate 10. A first isolation structure 20 is formed in the semiconductor substrate 10 for defining a plurality of pixel regions PX in the semiconductor substrate 10. At least one visible light detecting structure PD2 is formed in the semiconductor substrate 10. The semiconductor substrate 10 has a first surface S1 and a second surface S2 opposite to each other in a vertical direction (e.g., the first direction D1), the visible light detecting structure PD2 is located within one of the pixel regions PX in the semiconductor substrate 10, and a first portion P1 of the visible light detecting structure PD2 is located between the infrared light detecting structure PD1 and the second surface S2 of the semiconductor substrate 10 in the first direction D1.

[0088] Further, the method of fabricating the image sensor 101 of the present embodiment can include, but not limited to, the following steps. As shown, a plurality of trenches TR can be formed on one side of the first surface S1 of the semiconductor substrate 10. Then, as shown, Figure 4 Figure 5 An epitaxial fabrication process 90 can be performed to form an epitaxial structure ES on the semiconductor substrate 10 and fill the epitaxial structure ES into each of the trenches TR. The epitaxial fabrication process 90 can include an epitaxial growth fabrication process or other fabrication methods that can be used to form the epitaxial structure ES. In addition, the epitaxial structure ES can include a plurality of epitaxial layers (e.g., the epitaxial layers shown in the above-mentioned Figure 2 Since the infrared light detecting structure PD1 can be formed in the trench TR by the epitaxial fabrication process 90, a material with a higher infrared light absorption rate can be used to form the infrared light detecting structure PD1 to improve the photoelectric conversion capability of the infrared light detecting structure PD1, and the material composition of the infrared light detecting structure PD1 can thus be different from that of the semiconductor substrate 10.

[0089] Then, as shown, Figure 6 The first isolation structure 20 and the second isolation structure 22 are formed in the semiconductor substrate 10 to define a plurality of pixel regions PX in the semiconductor substrate 10. In some embodiments, the first isolation structure 20 and the second isolation structure 22 can respectively extend from the first surface S1 of the semiconductor substrate 10 toward the second surface S2, the length L3 of the first isolation structure 20 in the first direction D1 can be greater than the length L2 of the second isolation structure 22 in the first direction D1, and the length L2 of the second isolation structure 22 in the first direction D1 can be greater than or equal to the length L1 of the infrared light detecting structure PD1 in the first direction D1, but not limited thereto.

[0090] After that, as shown, Figure 7 ​As shown, a visible light detection structure PD2 can be formed in the semiconductor substrate 10, and a first gate G1, a second gate G2, and other related components (e.g., the transistors described above) can be formed on the first surface S1 of the semiconductor substrate 10. In some embodiments, the visible light detection structure PD2 can include a doped region DR formed in the semiconductor substrate 10, and the doped region DR can be formed by a doping fabrication process performed on the semiconductor substrate 10. Thus, the doped region DR can include a portion of the semiconductor substrate 10 (e.g., silicon) and dopants implanted in the semiconductor substrate 10 by the doping fabrication process. In some embodiments, the doped region DR can include one or more doped regions having different conductivity types (e.g., n-type doped regions or / and p-type doped regions), and the dopants used in the doping fabrication process can include phosphorus (P), arsenic (As), or other suitable dopants. In addition, the implantation dose used in the doping fabrication process can be between 1E+11 ion / cm2and 1E+13 ion / cm2, but is not limited thereto. Furthermore, in some embodiments, since the infrared light detection structure PD1 and the second isolation structure 22 can be formed before the visible light detection structure PD2, the doping fabrication process described above can be performed on the first surface S1 or / and the second surface S2 of the semiconductor substrate 10. Thus, the visible light detection structure PD2 having a desired range can be formed and the negative impact of the doping fabrication process on the infrared light detection structure PD1 can be reduced. 2 2

[0091] Figure 8 Figure 9 As shown, a reflective structure 30, a contact structure 32, a contact structure 34, a reflective layer 36, an interconnect structure 40, and a dielectric layer 50 can be formed on the first surface S1 of the semiconductor substrate 10, and an anti-reflective layer 60 and a patterned isolation structure 62 can be formed on the second surface S2 of the semiconductor substrate 10. In some embodiments, before the anti-reflective layer 60 is formed, a thinning fabrication process can be performed from the second surface S2 of the semiconductor substrate 10 to remove a portion of the semiconductor substrate 10 to thin the semiconductor substrate 10, and the first isolation structure 20 can be formed through the semiconductor substrate 10 in the first direction D1 after the thinning fabrication process, but is not limited thereto. After that, as shown in FIG. 3B, Figure 9 Figure 1 ​​​​​As shown, the color filter units 70 and the microlenses 80 can be formed, thereby forming the image sensor 101. In some embodiments, the second surface S2 can be regarded as the light-incoming surface or the side facing the light source, and the infrared light detecting structure PD1 and the visible light detecting structure PD2 can be disposed between the second surface S2 and the circuit structure (e.g., the transistors corresponding to the first gate G1 and the second gate G2 and the interconnection structure 40) in the first direction D1, so the image sensor 101 can be regarded as a backside illumination image sensor, but is not limited thereto. In addition, the manufacturing method of the image sensor 101 of the present embodiment is not limited to the above-mentioned manufacturing method, and other suitable manufacturing methods can be used to form the image sensor 101 according to the design requirements. Figures 4 to 9 The manufacturing method of the image sensor 101 of the present embodiment is not limited to the above-mentioned manufacturing method, and other suitable manufacturing methods can be used to form the image sensor 101 according to the design requirements.

[0092] Hereinafter, different embodiments of the present application will be described, and for the sake of simplicity, the following description mainly focuses on the different parts of each embodiment, and the same parts will not be repeatedly described. In addition, the same elements in each embodiment of the present application are denoted by the same reference numerals, so as to facilitate mutual comparison between each embodiment.

[0093] Please refer to Figure 10 . Figure 10 The image sensor 102 of the second embodiment of the present application is shown in the schematic diagram. As shown, Figure 10 In some embodiments, the reflective layer 36 can extend in the horizontal direction and correspond to the infrared light detecting structure PD1 and the visible light detecting structure PD2 disposed in the same pixel region PX, so the visible light detecting structure PD2 can be disposed between the reflective layer 36 and the second surface S2 of the semiconductor substrate 10 in the first direction D1. Through the arrangement of the reflective layer 36, the amount of light entering the infrared light detecting structure PD1 and the visible light detecting structure PD2 can be increased, thereby improving the detection capability of the image sensor 102 for infrared light or / and visible light.

[0094] In summary, in the image sensor of the present application, the visible light detecting structure and the infrared light detecting structure can be disposed in the same pixel region in the semiconductor substrate, thereby improving the photosensitivity and quantum efficiency of the image sensor for infrared light detection.

[0095] The above-mentioned only for the preferred embodiments of the present application, any equivalent changes and modifications made in accordance with the claims of the present application, should be within the scope of the present application.

Claims

1. An image sensor, characterized in that, include: A semiconductor substrate having a first surface and a second surface that are opposite each other in a vertical direction; A first isolation structure is disposed in the semiconductor substrate and is used to define multiple pixel regions in the semiconductor substrate; At least one visible light detection structure is disposed in the semiconductor substrate; At least one infrared light detection structure is disposed in the semiconductor substrate, wherein the at least one visible light detection structure and the at least one infrared light detection structure are disposed within one of the plurality of pixel regions, and a first portion of the at least one visible light detection structure is disposed in the vertical direction between the at least one infrared light detection structure and the second surface of the semiconductor substrate; as well as A reflective layer is disposed on the first surface of the semiconductor substrate, wherein the at least one infrared light detection structure is disposed in the vertical direction between the reflective layer and the first portion of the at least one visible light detection structure, wherein the reflective layer is an electrically floating conductive layer. The material composition of the at least one infrared light detection structure is different from the material composition of the at least one visible light detection structure.

2. The image sensor of claim 1, wherein each pixel region is surrounded by the first isolation structure in the horizontal direction.

3. The image sensor of claim 1, wherein the second portion of the at least one visible light detection structure is disposed horizontally between the first isolation structure and the at least one infrared light detection structure.

4. The image sensor of claim 3, wherein the second portion of the at least one visible light detection structure is directly connected to the first portion of the at least one visible light detection structure.

5. The image sensor as described in claim 3, further comprising: A second isolation structure is disposed in the semiconductor substrate, wherein a portion of the second isolation structure is disposed in the horizontal direction between the second portion of the at least one infrared light detection structure and the at least one visible light detection structure.

6. The image sensor of claim 5, wherein the first portion of the at least one visible light detection structure is disposed in the vertical direction between the second isolation structure and the second surface of the semiconductor substrate.

7. The image sensor of claim 5, wherein the length of the second isolation structure in the vertical direction is greater than or equal to the length of the at least one infrared light detection structure in the vertical direction.

8. The image sensor of claim 5, wherein the length of the second isolation structure in the vertical direction is less than the length of the first isolation structure in the vertical direction.

9. The image sensor of claim 1, wherein the at least one visible light detection structure is disposed in the vertical direction between the reflective layer and the second surface of the semiconductor substrate.

10. The image sensor of claim 1, further comprising: A first gate is disposed on the first surface of the semiconductor substrate and is disposed corresponding to the at least one infrared light detection structure; as well as The second gate is disposed on the first surface of the semiconductor substrate and is disposed corresponding to the at least one visible light detection structure.

11. The image sensor of claim 10, further comprising: A reflective structure is disposed on the first surface of the semiconductor substrate, wherein a portion of the reflective structure is disposed on the first isolation structure in the vertical direction, and another portion of the reflective structure is disposed between the first gate and the second gate.

12. The image sensor of claim 11, further comprising: A second isolation structure is disposed in the semiconductor substrate, wherein a portion of the second isolation structure is disposed horizontally between a second portion of the at least one infrared light detection structure and the at least one visible light detection structure, and the reflective structure disposed between the first gate and the second gate at least partially overlaps the second isolation structure in the vertical direction.

13. The image sensor of claim 11, wherein the reflective structure is an electrically floating conductive structure.

14. The image sensor of claim 1, further comprising: Multiple color filter units are disposed on the second surface of the semiconductor substrate, wherein each color filter unit is disposed corresponding to one of the multiple pixel regions in the vertical direction.

15. The image sensor of claim 1, wherein a portion of the first isolation structure extends through the semiconductor substrate in the vertical direction.

16. The image sensor of claim 1, wherein the vertical direction is the thickness direction of the semiconductor substrate.

17. The image sensor of claim 1, wherein the at least one visible light detection structure comprises a visible light photodiode or a portion thereof, and the at least one infrared light detection structure comprises an infrared light photodiode or a portion thereof.

18. The image sensor of claim 1, wherein the at least one infrared light detection structure includes an epitaxial structure disposed in the semiconductor substrate, the at least one visible light detection structure includes a doped region, and the doped region includes the same material as the semiconductor substrate.

19. An image sensor, characterized in that, include: A semiconductor substrate having a first surface and a second surface that are opposite each other in a vertical direction; A first isolation structure is disposed in the semiconductor substrate and is used to define multiple pixel regions in the semiconductor substrate; At least one visible light detection structure is disposed in the semiconductor substrate; At least one infrared light detection structure is disposed in the semiconductor substrate, wherein the at least one visible light detection structure and the at least one infrared light detection structure are disposed within one of the plurality of pixel regions, and a first portion of the at least one visible light detection structure is disposed in the vertical direction between the at least one infrared light detection structure and the second surface of the semiconductor substrate; A first gate is disposed on the first surface of the semiconductor substrate and is disposed corresponding to the at least one infrared light detection structure; The second gate is disposed on the first surface of the semiconductor substrate and is disposed corresponding to the at least one visible light detection structure; as well as A reflective structure is disposed on the first surface of the semiconductor substrate, wherein a portion of the reflective structure is disposed on the first isolation structure in the vertical direction, and another portion of the reflective structure is disposed between the first gate and the second gate, wherein the reflective structure is an electrically floating conductive structure.

20. An image sensor, characterized in that, include: A semiconductor substrate having a first surface and a second surface that are opposite each other in a vertical direction; A first isolation structure is disposed in the semiconductor substrate and is used to define multiple pixel regions in the semiconductor substrate; At least one visible light detection structure is disposed in the semiconductor substrate; At least one infrared light detection structure is disposed in the semiconductor substrate, wherein the at least one visible light detection structure and the at least one infrared light detection structure are disposed within one of the plurality of pixel regions, and a first portion of the at least one visible light detection structure is disposed in the vertical direction between the at least one infrared light detection structure and the second surface of the semiconductor substrate; A first gate is disposed on the first surface of the semiconductor substrate and is disposed corresponding to the at least one infrared light detection structure; The second gate is disposed on the first surface of the semiconductor substrate and is disposed corresponding to the at least one visible light detection structure; A reflective structure is disposed on the first surface of the semiconductor substrate, wherein a portion of the reflective structure is disposed on the first isolation structure in the vertical direction, and another portion of the reflective structure is disposed between the first gate and the second gate; as well as A second isolation structure is disposed in the semiconductor substrate, wherein a portion of the second isolation structure is disposed horizontally between a second portion of the at least one infrared light detection structure and the at least one visible light detection structure, and the reflective structure disposed between the first gate and the second gate at least partially overlaps the second isolation structure in the vertical direction.

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