CN110634901A - Image sensor - Google Patents
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- CN110634901A CN110634901A CN201910945298.6A CN201910945298A CN110634901A CN 110634901 A CN110634901 A CN 110634901A CN 201910945298 A CN201910945298 A CN 201910945298A CN 110634901 A CN110634901 A CN 110634901A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14603—Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14603—Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
- H01L27/14605—Structural or functional details relating to the position of the pixel elements, e.g. smaller pixel elements in the center of the imager compared to pixel elements at the periphery
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14609—Pixel-elements with integrated switching, control, storage or amplification elements
- H01L27/14612—Pixel-elements with integrated switching, control, storage or amplification elements involving a transistor
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/1464—Back illuminated imager structures
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
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Abstract
The embodiment of the invention provides an image sensor, which comprises a substrate, a first electrode, a second electrode and a third electrode, wherein the substrate is provided with a first surface and a second surface which are opposite; the substrate is provided with a photosensitive area on one side close to the second surface, and the photosensitive area is used for receiving incident light irradiation and generating photo-generated carrier pairs with a first electric property and a second electric property; the substrate is provided with a transmission channel corresponding to the photosensitive area on one side close to the first surface, and the transmission channel is used for transmitting the photon-generated carriers with the first electrical property to a specific position and guiding the photon-generated carriers out of the substrate from the specific position; the second surface of the substrate is provided with a first groove extending towards the first surface, the first groove is located at the edge of the photosensitive area, and a conductor material used for loading a first electric voltage is arranged in the first groove.
Description
Technical Field
The invention relates to the technical field of image sensing, in particular to an image sensor.
Background
The image sensor is a device for converting an optical image into an electrical signal, and generates photo-generated carriers (positive charges and negative charges, or called electron-hole pairs) when the photosensitive region receives incident light irradiation by using a photoelectric conversion function of the photosensitive region, so that a photo-image is converted into the electrical signal in a corresponding proportional relation with the photo-image; and then the electric signal is led out and read, so that the image sensing function is realized.
However, the conventional image sensor often has a problem that charges far away from the transfer transistor cannot be led out of the substrate to cause charge residue; particularly for a back-illuminated image sensor, such a charge retention problem is more pronounced due to the larger thickness of the substrate, thereby causing image smear defects. In order to solve the problem of charge residue, the related art proposes to adjust the ion injection gradient of an N-type well region in a substrate, so that a photogenerated carrier is maximally pulled to a floating diffusion region; however, when the ion implantation depth is too deep or the ion implantation process is unstable, the ion implantation gradient of the N-type well region is difficult to be ensured, and the problem of charge residue still cannot be solved well.
Disclosure of Invention
In view of the above, the present invention is directed to an image sensor.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
an embodiment of the present invention provides an image sensor, including:
a substrate having opposing first and second surfaces;
the substrate is provided with a photosensitive area on one side close to the second surface, and the photosensitive area is used for receiving incident light irradiation and generating photo-generated carrier pairs with a first electric property and a second electric property;
the substrate is provided with a transmission channel corresponding to the photosensitive area on one side close to the first surface, and the transmission channel is used for transmitting the photon-generated carriers with the first electrical property to a specific position and guiding the photon-generated carriers out of the substrate from the specific position;
the second surface of the substrate is provided with a first groove extending towards the first surface, the first groove is located at the edge of the photosensitive area, and a conductor material used for loading a first electric voltage is arranged in the first groove.
In the above scheme, the first electrical property is negative, and the range of the first electrical voltage loaded on the conductor material is-0.5 to-3V.
In the above scheme, the sidewall of the first trench is inclined toward the direction of the photosensitive region.
In the above scheme, an included angle between the side wall of the first groove and the first surface is greater than or equal to 60 ° and less than 90 °.
In the above scheme, a first opening width of the first trench at the second surface ranges from 0.1 μm to 0.8 μm, a second opening width of the bottom of the first trench in the substrate ranges from 0.1 μm to 0.2 μm, and a depth of the first trench in the substrate ranges from 0.1 μm to 2 μm.
In the above solution, a width of a first opening of the first trench at the second surface is smaller than a width of the photosensitive region.
In the above aspect, the conductor material includes at least one of: TiN-Ti-W stack, TiN-Ti-Cu stack, TiN-Ti-Al stack.
In the above scheme, the width range of the conductor material at the second surface is 0.05-0.4 μm, the width range of the bottom of the conductor material in the substrate is 0.05-0.4 μm, and the depth range of the conductor material in the substrate is 0.09-1.8 μm.
In the above scheme, an insulating layer is further disposed in the first trench, and the insulating layer is used to electrically isolate the conductor material from the substrate.
In the above scheme, the material of the insulating layer includes silicon oxide.
In the above solution, the first surface of the substrate further has a second trench extending toward the second surface, and a position of the second trench corresponds to a position of the first trench; the second trench is a shallow isolation trench STI, and the first trench is a deep isolation trench DTI.
In the above scheme, the bottom of the first trench and the bottom of the second trench are joined in the substrate.
The image sensor provided by the embodiment of the invention comprises a substrate, a first electrode and a second electrode, wherein the substrate is provided with a first surface and a second surface which are opposite; the substrate is provided with a photosensitive area on one side close to the second surface, and the photosensitive area is used for receiving incident light irradiation and generating photo-generated carrier pairs with a first electric property and a second electric property; the substrate is provided with a transmission channel corresponding to the photosensitive area on one side close to the first surface, and the transmission channel is used for transmitting the photon-generated carriers with the first electrical property to a specific position and guiding the photon-generated carriers out of the substrate from the specific position; the second surface of the substrate is provided with a first groove extending towards the first surface, the first groove is located at the edge of the photosensitive area, and a conductor material used for loading a first electric voltage is arranged in the first groove. Therefore, by arranging the first groove structure, the first electric voltage is loaded on the conductor material in the first groove structure, so that an electric field force which is repellent to the photo-generated carriers with the first electric property is generated, the photo-generated carriers with the first electric property are pushed to the transmission channel under the action of the electric field force, and the substrate is further led out, the charge residue problem of the image sensor is solved, and the image smear defect is improved.
Drawings
Fig. 1 is a schematic structural diagram of an image sensor according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a method for manufacturing an image sensor according to an embodiment of the present invention;
fig. 3 to 9 are schematic cross-sectional views of device structures in a manufacturing process of an image sensor according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present invention; that is, not all features of an actual embodiment are described herein, and well-known functions and structures are not described in detail.
In the drawings, the size of layers, regions, elements, and relative sizes may be exaggerated for clarity. Like reference numerals refer to like elements throughout.
It will be understood that when an element or layer is referred to as being "on" … …, "adjacent to … …," "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to the other elements or layers or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on … …," "directly adjacent to … …," "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. And the discussion of a second element, component, region, layer or section does not necessarily imply that a first element, component, region, layer or section is present in the invention.
Spatial relationship terms such as "under … …", "under … …", "below", "under … …", "above … …", "above", and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, then elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "below … …" and "below … …" can encompass both an orientation of up and down. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.
In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The following detailed description of the preferred embodiments of the invention, however, the invention is capable of other embodiments in addition to those detailed.
Fig. 1 is a schematic structural diagram of an image sensor according to an embodiment of the present invention. As shown in the figure, the image sensor of the embodiment of the invention includes a substrate 100, the substrate 100 having a first surface 101 and a second surface 102 opposite to each other; the substrate 100 has a photosensitive area on a side near the second surface 102, the photosensitive area being configured to receive incident light and generate photo-carrier pairs having a first electrical property and a second electrical property; the substrate 100 has a transport channel corresponding to the photosensitive region on a side close to the first surface 101, and the transport channel is used for transporting photo-generated carriers with first electrical property to a specific position and leading the photo-generated carriers out of the substrate 100 from the specific position; the second surface 102 of the substrate 100 has a first trench T1 extending toward the first surface 101, the first trench T1 is located at the edge of the photosensitive region, and a conductor material 112 for applying a first electrical voltage is disposed in the first trench T1.
Here, for convenience of understanding, taking a 4T pixel image sensor as an example, the pixel region is composed of 4 transfer gates Tx (only 2 transfer gates Tx1 and Tx2 are schematically drawn in fig. 1), a source follower device, a row selection device, a reset device, a photosensitive region, and the like. The incident light filtered by the optical filter generates and accumulates charges (equivalent to photo-generated carriers with first electrical property) in the corresponding photosensitive region, after the transmission gate Tx is turned on, the charges are transmitted into a Floating Diffusion (FD), the charges are converted into a voltage for subsequent processing by the source follower device, and the voltage signal is output through the common output column by the row selection device. The reset device performs a reset function after performing one operation.
When the image sensor works, a first electrical voltage is loaded on the conductor material 112 in the first trench structure T1, so that an electric field force repelling the photo-generated carriers with the first electrical property is generated, and the photo-generated carriers with the first electrical property are pushed to the transmission channel under the action of the electric field force, so as to lead out the substrate 100, thereby solving the charge residue problem of the image sensor and improving the image smear defect.
The substrate 100 is, for example, a silicon substrate; in other embodiments, a germanium substrate, a silicon carbide substrate, a germanium-silicon substrate, or the like may also be included.
A transfer gate Tx is formed on the first surface 101 of the substrate 100, and the transfer channel is formed in the substrate 100 corresponding to the transfer gate Tx. When the transmission gate Tx is turned on, the transmission channel plays a role of transferring charges, so that photo-generated carriers are transmitted to a specific position; it will be appreciated that the particular location here is, for example, a floating diffusion region FD from which photogenerated carriers are then directed out of the substrate 100.
In one embodiment, the first electrical property is negative, that is, the photogenerated carriers with the first electrical property are photoelectrons; at this time, the first electric voltage applied to the conductive material 112 ranges from-0.5 to-3V, so that photoelectrons are pushed toward the transfer channel by repulsion of the negative voltage.
Please continue to refer to fig. 1. As a specific embodiment, the sidewall of the first trench T1 is inclined toward the direction of the photosensitive region. Therefore, the pushing capability of the electric field force generated during working to the photoelectrons is better; in this embodiment, an included angle between the sidewall of the first trench T1 and the first surface 101 is preferably greater than or equal to 60 ° and less than 90 °, and at this time, not only the generated electric force is good in pushing capability, but also the encroachment of the first trench T1 on the substrate 100 is minimized.
Further, the first opening width of the first trench T1 at the second surface 102 should be smaller than the width of the photosensitive area, so as to avoid adversely affecting the photosensitive performance of the image sensor.
In one embodiment, a first opening width of the first trench T1 at the second surface 102 is in a range of 0.1-0.8 μm, a second opening width of the bottom of the first trench T1 in the substrate 100 is in a range of 0.1-0.2 μm, and a depth of the first trench T1 in the substrate 100 is in a range of 0.1-2 μm. Here, the first trench T1 is a Deep isolation trench (DTI); the size of the device can be adjusted according to the actual performance and the process capability of the device; the first trench T1 is formed, for example, by a dry etching process.
After the first trench T1 is formed, an insulating layer 111 may be filled in the first trench T1; the insulating layer 111 is used to electrically isolate the subsequently formed conductive material 112 from the substrate 100, so as to prevent external electrons from flowing into the substrate 100 after the conductive material 112 is applied with a voltage, thereby causing noise.
In one embodiment, the material of the insulating layer 111 includes silicon oxide, such as SiO2. At this time, the incident light can penetrate the silicon oxide filled in the first trench T1, thereby minimizing the influence of the arrangement of the first trench T1 on the light sensing capability of the light sensing region.
Next, in order to form the conductor material 112 in the first trench T1, the insulating layer 111 may be etched to form a trench T2, so that the conductor material 112 is filled in the trench T2. The trench T2 may also be formed by a dry etching process.
The conductor material 112 includes at least one of: TiN-Ti-W stack, TiN-Ti-Cu stack, TiN-Ti-Al stack. Specifically, the outermost layer of the conductor material 112 is a TiN layer, the middle layer is a Ti layer, and the innermost layer is W, Cu or an Al layer.
The width of the conductor material 112 at the second surface 102 is 0.05-0.4 μm, the width of the bottom of the conductor material 112 in the substrate 100 is 0.05-0.4 μm, and the depth of the conductor material 112 in the substrate 100 is 0.09-1.8 μm. The size of the conductor material 112 is the size of the trench T2 formed by etching.
In an embodiment, the first surface 101 of the substrate 100 further has a second trench extending toward the second surface 102, and the position of the second trench corresponds to the position of the first trench; the second trench is a Shallow Trench Isolation (STI), and the first trench is a Deep Trench Isolation (DTI).
It is understood that the second trench STI separates each pixel of the image sensor. The position of the first trench T1 corresponds to the position of the second trench STI, that is, the first trench T1 is disposed at a position separated by each pixel at the edge of the photosensitive region. In one embodiment, the bottom of the first trench T1 and the bottom of the second trench STI meet within the substrate 100.
In addition, the image sensor may further include a dielectric layer 110, and the dielectric layer 110 covers the transmission gate Tx. The dielectric layer 110 further has a wiring layer 111 and the like.
The image sensor provided by the embodiment of the invention can be a back-illuminated image sensor; in another embodiment, the image sensor may also be a stacked image sensor.
In addition, the embodiment of the invention also provides a preparation method of the image sensor. Please refer to fig. 2. As shown, the method comprises the steps of:
The following describes the image sensor and the method for manufacturing the image sensor provided by the embodiment of the present invention in further detail with reference to the schematic cross-sectional views of the device structures in the process of manufacturing the image sensor in fig. 3 to 9.
First, please refer to fig. 3. A substrate 100 is provided to complete the front-end-of-line processing.
At this time, the substrate 100 has a first surface 101 and a second surface 102 opposite to each other. The substrate 100 has a photosensitive area on a side near the second surface 102, the photosensitive area being configured to receive incident light and generate photo-carrier pairs having a first electrical property and a second electrical property; in other words, after the image sensor is prepared and formed, the side of the second surface 102 is taken as the side of the image sensor facing the incident light. There is a second trench (shallow isolation trench STI) at the edge of the photosensitive region. The second trench STI separates each pixel of the image sensor. The substrate 100 has a transport channel corresponding to the photosensitive region on a side close to the first surface 101, and the transport channel is used for transporting photo-generated carriers with the first electrical property to a specific position and guiding the photo-generated carriers out of the substrate 100 from the specific position.
Here, a transfer gate Tx is formed on the first surface 101 of the substrate 100, and the transfer channel is formed in the substrate 100 under the transfer gate Tx. The specific position may specifically refer to a position where the floating diffusion FD is located; the photo-generated carriers with the first electrical property are transferred to the FD by the transfer channel, and then are led out of the substrate 100 from the FD.
A dielectric layer 110 is further stacked on the first surface 101 of the substrate 100, and the dielectric layer 110 covers the transmission gate Tx. A wiring layer 111 and the like are provided in the dielectric layer 110.
Next, please refer to fig. 4. Bonding a carrier substrate 120 on the first surface 101 side of the substrate 100; in particular, carrier substrate 120 may be bonded to the exposed surface of dielectric layer 110. The substrate 100 is turned over so that the second surface 102 faces upward, toward the process direction.
Next, please refer to fig. 5. The substrate 100 is thinned from the second surface 102 of the substrate 100. The specific process can adopt mechanical grinding, acid etching, chemical mechanical grinding and the like.
Next, please refer to fig. 6. A dry etching process is performed on the second surface 102 of the substrate 100 to form the first trench T1. The first trench T1 is located at the edge of the photosensitive area; in a specific embodiment, the first trench T1 is formed at a position corresponding to the position of the second trench STI. The bottom of the first trench T1 may meet the bottom of the second trench STI within the substrate 100.
In one embodiment, a first opening width of the first trench T1 at the second surface 102 is in a range of 0.1-0.8 μm, a second opening width of the bottom of the first trench T1 in the substrate 100 is in a range of 0.1-0.2 μm, and a depth of the first trench T1 in the substrate 100 is in a range of 0.1-2 μm. Here, the first trench T1 is a deep isolation trench DTI; the size of the device can be adjusted according to the actual performance and the process capability of the device; up to the bottom of the second trench STI, thereby forming a trench structure through the substrate 100.
The first trench T1 may be formed by etching in a direction perpendicular to the thickness of the substrate; however, as a better implementation, the sidewall of the first trench T1 is inclined toward the photosensitive region, so that the electric field force generated during operation can push the photoelectrons better. In this embodiment, an included angle between the sidewall of the first trench T1 and the first surface 101 is preferably greater than or equal to 60 ° and less than 90 °, and at this time, not only the generated electric force is good in pushing capability, but also the encroachment of the first trench T1 on the substrate 100 is minimized. The specific inclination angle of the sidewall of the first trench T1 can be adjusted according to the actual design requirement and the device performance.
Next, please refer to fig. 7. Filling an insulating layer 111 in the first trench T1; the insulating layer 111 is used to electrically isolate the subsequently formed conductive material 112 from the substrate 100, so as to prevent external electrons from flowing into the substrate 100 after the conductive material 112 is applied with a voltage, thereby causing noise.
In one embodiment, the material of the insulating layer 111 includes silicon oxide, such as SiO2. At this time, the incident light can penetrate the silicon oxide filled in the first trench T1, thereby minimizing the influence of the arrangement of the first trench T1 on the light sensing capability of the light sensing region.
Next, please refer to fig. 8. To form the conductor material 112 within the first trench T1, the insulating layer 111 is etched, forming a trench T2. The trench T2 may also be formed by a dry etching process.
In the etching process, the insulating layer 111 with a certain thickness is reserved at the bottom and the side wall of the first trench T1, for example, the insulating layer 111 with a thickness range of 0.01-0.2 um is reserved at the bottom of the first trench T1; in this way, it is ensured that the subsequently formed conductive material 112 is covered by the insulating layer 111 and has no portion directly contacting the substrate 100.
The width of the trench T2 at the second surface 102 is in the range of 0.05-0.4 μm, the width of the bottom of the trench T2 in the substrate 100 is in the range of 0.05-0.4 μm, and the depth of the trench T2 in the substrate 100 is in the range of 0.09-1.8 μm. The dimensions of the trench T2 are the dimensions of the conductor material 112 to be formed subsequently.
Next, please refer to fig. 9. The trench T2 is filled with a conductor material 112.
The conductive material 112 may be formed by a filling process of a metal connection hole in the art. The conductor material 112 includes at least one of: TiN-Ti-W stack, TiN-Ti-Cu stack, TiN-Ti-Al stack. Specifically, the outermost layer of the conductor material 112 is a TiN layer, the middle layer is a Ti layer, and the innermost layer is W, Cu or an Al layer.
Finally, the method may further include growing an oxide dielectric, forming deep through silicon vias, metal deposition, filter deposition, forming micro-lenses, etc. (not shown).
After the image sensor is fabricated, the conductive material 112 in the first trench T1 is connected to a negative voltage input terminal using an additional metal connection, so that the image sensor can be loaded with a negative voltage, for example, -0.5 to-3V, during operation. Of course, the specific voltage range needs to be adjusted by the actual performance of the device.
It should be noted that the embodiment of the image sensor provided by the invention and the embodiment of the manufacturing method of the image sensor belong to the same concept; the technical features of the technical means described in the embodiments may be arbitrarily combined without conflict.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents, improvements, etc. that are within the spirit and principle of the present invention should be included in the present invention.
Claims (12)
1. An image sensor, comprising:
a substrate having opposing first and second surfaces;
the substrate is provided with a photosensitive area on one side close to the second surface, and the photosensitive area is used for receiving incident light irradiation and generating photo-generated carrier pairs with a first electric property and a second electric property;
the substrate is provided with a transmission channel corresponding to the photosensitive area on one side close to the first surface, and the transmission channel is used for transmitting the photon-generated carriers with the first electrical property to a specific position and guiding the photon-generated carriers out of the substrate from the specific position;
the second surface of the substrate is provided with a first groove extending towards the first surface, the first groove is located at the edge of the photosensitive area, and a conductor material used for loading a first electric voltage is arranged in the first groove.
2. The image sensor as in claim 1, wherein the first electrical property is negative, and the voltage of the first electrical property applied to the conductive material is in a range of-0.5V to-3V.
3. The image sensor of claim 1, wherein sidewalls of the first trench are sloped toward a direction of the photosensitive region.
4. The image sensor of claim 3, wherein the sidewall of the first trench forms an angle with the first surface in a range of 60 ° or more and less than 90 °.
5. The image sensor of claim 1, wherein a first opening width of the first trench at the second surface is in a range of 0.1-0.8 μm, a second opening width of the first trench bottom in the substrate is in a range of 0.1-0.2 μm, and a depth of the first trench in the substrate is in a range of 0.1-2 μm.
6. The image sensor of claim 1, wherein a first opening width of the first trench at the second surface is less than a width of the photosensitive region.
7. The image sensor of claim 1, wherein the conductor material comprises at least one of: TiN-Ti-W stack, TiN-Ti-Cu stack, TiN-Ti-Al stack.
8. The image sensor of claim 1, wherein the width of the conductive material at the second surface is in a range of 0.05-0.4 μm, the width of the bottom of the conductive material within the substrate is in a range of 0.05-0.4 μm, and the depth of the conductive material within the substrate is in a range of 0.09-1.8 μm.
9. The image sensor of claim 1, wherein an insulating layer is further disposed within the first trench, the insulating layer for electrically isolating the conductor material from the substrate.
10. The image sensor of claim 9, wherein the material of the insulating layer comprises silicon oxide.
11. The image sensor of claim 1, further comprising a second trench on the first surface of the substrate extending toward the second surface, the second trench corresponding in position to the first trench; the second trench is a shallow isolation trench STI, and the first trench is a deep isolation trench DTI.
12. The image sensor of claim 11, wherein a bottom of the first trench is contiguous with a bottom of the second trench within the substrate.
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| US20170005121A1 (en) * | 2015-06-30 | 2017-01-05 | Semiconductor Components Industries, Llc | Image sensors with backside trench structures |
| CN108281436A (en) * | 2018-01-15 | 2018-07-13 | 德淮半导体有限公司 | Cmos image sensor and forming method thereof |
| CN110246856A (en) * | 2019-06-14 | 2019-09-17 | 芯盟科技有限公司 | Forming method, imaging sensor and its working method of imaging sensor |
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| CN104217987A (en) * | 2013-05-31 | 2014-12-17 | 爱思开海力士有限公司 | Isolation structure and method for forming the same, and image sensor including the isolation structure and method for fabricating the image sensor |
| US20170005121A1 (en) * | 2015-06-30 | 2017-01-05 | Semiconductor Components Industries, Llc | Image sensors with backside trench structures |
| CN108281436A (en) * | 2018-01-15 | 2018-07-13 | 德淮半导体有限公司 | Cmos image sensor and forming method thereof |
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