Image sensor charge signal interference monitoring device and monitoring method

Abstract

This invention provides an image sensor charge signal interference monitoring device and method. Through the pixel monitoring structure, adjustable power supply, and voltmeter electrically connected in the image sensor charge signal interference monitoring device, charge signal interference problems of the image sensor can be conveniently, efficiently, and accurately monitored. It can be used in product mass production processes to monitor product parameter characteristics and quality stability. Furthermore, it can be used for evaluation and analysis before the product chip is completed, to promptly identify products that do not meet target standard parameters, conduct timely analysis and processing, find the cause, provide solutions, and reduce losses. Therefore, the image sensor charge signal interference monitoring device and method of this invention can effectively save production costs and time.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to an image sensor charge signal interference monitoring device and monitoring method. Background Technology

[0002] An image sensor is a functional device that uses the photoelectric conversion function of optoelectronic devices to convert a light image on a photosensitive surface into an electrical signal that is proportional to the light image. Image sensors include two types: CMOS (Complementary Metal-Oxide Semiconductor) image sensors and CCD (Charged Coupled Device) image sensors, which are widely used in digital cameras, mobile phones, medical devices, automobiles, and other applications.

[0003] CCD image sensors and CMOS image sensors each have their advantages in different application scenarios. However, with the rapid development and continuous improvement of manufacturing processes and technologies for CMOS image sensors, as well as the continuous decline in the price of high-end CMOS, CMOS is occupying an increasingly important position, and people have higher requirements for the image quality output of CMOS image sensors.

[0004] In a CMOS image sensor, a photosensitive pixel array is incorporated to collect photoelectric signals of the image. When external light shines on the pixel array, the photoelectric effect occurs, generating corresponding charges within the pixel units. Typically, the pixel array uses a Bayer pixel array layout. A Bayer pixel array contains red, green, and blue pixels, each with a photodiode as a photosensitive area. These photodiodes collect the photoelectric charge of the corresponding color of light. However, photodiodes may saturate at different exposure times. Excess photoelectric charge from the first saturated photodiode may overflow into the sensor substrate. This overflowing charge then moves within the substrate to the vicinity of nearby photodiodes, where it is absorbed. This phenomenon, where charge overflows from photodiodes into the substrate and is then absorbed by neighboring photodiodes, is called charge signal interference.

[0005] The phenomenon of charge signal interference can cause pink or purple edges to appear at the edges of bright images in images acquired by image sensors. This is especially true for small-area image sensors, where the distance between the photodiodes of adjacent pixel units is relatively close, making the pink or purple edge problem more likely to occur.

[0006] In the mass production process of image sensor chips in the current technology, due to the limitation of manufacturing process precision, the characteristics and quality of the chips may fluctuate. Some production batches of chips may have problems with charge signal interference. If a defective chip that does not meet the product quality requirements is found, it needs to be scrapped.

[0007] Therefore, it is necessary to provide a device and method for timely monitoring of charge signal interference in image sensors. Summary of the Invention

[0008] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an image sensor charge signal interference monitoring device and monitoring method to solve the problems of product quality and resource waste caused by charge signal interference in the prior art.

[0009] To achieve the above and other related objectives, the present invention provides an image sensor charge signal interference monitoring device, the image sensor charge signal interference monitoring device comprising:

[0010] A pixel monitoring structure includes a semiconductor substrate, a charge transport transistor, and a photoelectric conversion region disposed in the semiconductor substrate. One side of the photoelectric conversion region is connected to the source terminal of the charge transport transistor, the drain terminal of the charge transport transistor is a floating diffuse active region, and a substrate contact region is also provided in the semiconductor substrate. The substrate contact region has the same conductivity type as the semiconductor substrate and is grounded.

[0011] An adjustable power supply, one end of which is connected to the photoelectric conversion area, and the other end of which is grounded;

[0012] A voltmeter, one end of which is connected to the floating diffusion active region, and the other end of which is grounded.

[0013] Optionally, the semiconductor substrate further includes an isolation region, which includes a first isolation region, a second isolation region, and a third isolation region. The first isolation region is located on the side of the floating diffusion active region away from the photoelectric conversion region. The second isolation region and the third isolation region are located sequentially on the side of the photoelectric conversion region away from the floating diffusion active region. The substrate contact region is located between the second isolation region and the third isolation region.

[0014] Optionally, the voltage regulation range of the adjustable power supply includes -1V to 1V.

[0015] Optionally, the semiconductor substrate and the substrate contact region have a first ion doping type, the photoelectric conversion region has a second ion doping type, and the photoelectric conversion region is further provided with a first ion doping type protective layer, the first ion doping type protective layer has a contact opening, and the photoelectric conversion region is connected to the adjustable power supply through the contact opening.

[0016] Optionally, contact portions are provided in the photoelectric conversion region, the substrate contact region, and the floating diffusion active region to form ohmic contacts.

[0017] Optionally, the semiconductor substrate includes a chip region and a dicing region, and the pixel monitoring structure is disposed in the dicing region.

[0018] The present invention also provides a method for monitoring charge signal interference in an image sensor, comprising the following steps:

[0019] Provide a charge signal interference monitoring device for any of the above-mentioned image sensors;

[0020] Set the charge transfer transistor to the off state;

[0021] Adjust the voltage of the adjustable power supply and obtain the reading value of the voltmeter;

[0022] Data analysis is performed on the readings of the voltmeter to obtain the charge signal interference information of the image sensor.

[0023] Optionally, the adjustable power supply scans the voltage from negative to positive starting from negative voltage.

[0024] Optionally, the method for data analysis of the reading value of the voltmeter includes: when the obtained reading value of the voltmeter remains unchanged at its initial value, the image sensor pixel unit exhibits charge signal interference.

[0025] Optionally, the method for analyzing the readings of the voltmeter includes:

[0026] When the initial reading of the voltmeter remains unchanged, then the reading increases, and finally the final reading remains unchanged, the final voltage value and the initial voltage value of the voltmeter are obtained, and the difference between the final voltage value and the initial voltage value is calculated to obtain the voltage change ΔU.

[0027] When 0.1V > ΔU > 0V, there is a small amount of charge signal interference.

[0028] When 0.3V > ΔU > 0.1V, there is no charge signal interference problem, and the charge signal saturation capacity of the photodiode is within the target range;

[0029] When ΔU>0.3V, there is no charge signal interference problem, and the charge signal saturation capacity of the photodiode is reduced and is not within the target range.

[0030] As described above, the image sensor charge signal interference monitoring device and method of the present invention, through the pixel monitoring structure, adjustable power supply, and voltmeter electrically connected in the image sensor charge signal interference monitoring device, can conveniently, efficiently, and accurately monitor charge signal interference problems of image sensors. It can be used in product mass production processes to monitor product parameter characteristics and quality stability. Furthermore, it can be used for evaluation and analysis before the product chip is completed, to promptly identify products that do not meet target standard parameters, conduct timely analysis and processing, find the causes, provide solutions, and reduce losses. Therefore, the image sensor charge signal interference monitoring device and method of the present invention can effectively save production costs and time costs. Attached Figure Description

[0031] Figure 1 The diagram shown is a structural schematic of the image sensor charge signal interference monitoring device in an embodiment of the present invention.

[0032] Figure 2 The diagram shown is a potential well diagram of the image sensor charge signal interference monitoring method in an embodiment of the present invention when charge signal interference exists.

[0033] Figure 3 The diagram shown illustrates the potential well for monitoring image sensor charge signal interference in an embodiment of the present invention when there is no charge signal interference.

[0034] Figure 4 The diagram shown illustrates the relationship between scanning the PD voltage and obtaining the FD voltage in the image sensor charge signal interference monitoring method according to an embodiment of the present invention.

[0035] Component designation explanation

[0036] 100 P-type semiconductor substrate

[0037] 101 Photodiode N-type region

[0038] 102 Photodiode Protective Layer

[0039] 103 Charge Transport Transistor

[0040] 104 Floating Diffusion Active Region

[0041] 105 P + Matrix contact area

[0042] 1061 First Quarantine Zone

[0043] 1062 Second Quarantine Zone

[0044] 1063 Third Quarantine Zone

[0045] 107 Regulated Power Supply

[0046] 108 Voltmeter

[0047] 109 Contact Department

[0048] Potential wells 201, 202, and 203

[0049] 21, 22 passage

[0050] Curves 301, 302, 303, and 304 Detailed Implementation

[0051] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0052] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0053] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for the device in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or there may be one or more layers in between. The phrase “between” as used herein includes both endpoint values.

[0054] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0055] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0056] This embodiment provides an image sensor charge signal interference monitoring device, which includes: a pixel monitoring structure, an adjustable power supply, and a voltmeter. The pixel monitoring structure includes a semiconductor substrate, a charge transport transistor, and a photoelectric conversion region disposed within the semiconductor substrate. One side of the photoelectric conversion region is connected to the source terminal of the charge transport transistor, and the drain terminal of the charge transport transistor is a floating diffusion active region. A substrate contact region is also provided in the semiconductor substrate, having the same conductivity type as the semiconductor substrate and being grounded. One end of the adjustable power supply is connected to the photoelectric conversion region, and the other end is grounded. One end of the voltmeter is connected to the floating diffusion active region, and the other end is grounded.

[0057] The image sensor charge signal interference monitoring device described in this embodiment, through the electrically connected pixel monitoring structure, adjustable power supply, and voltmeter, can conveniently, efficiently, and accurately monitor the charge signal interference problem of the image sensor. It can be used in product mass production process engineering to monitor product parameter characteristics and quality stability. Furthermore, it can be used for evaluation and analysis before the product chip is completed to promptly identify products that do not meet the target standard parameters, conduct timely analysis and processing, find the cause, provide solutions to problems, and reduce losses.

[0058] Specifically, the image sensor charge signal interference monitoring device can be applied to a front-illuminated CMOS image sensor, a back-illuminated CMOS image sensor, or a CCD image sensor, and the pixel structure in the image sensor may include four transistors, five transistors, six transistors, and seven transistors, etc.; the semiconductor substrate may be a P-type doped substrate or an N-type doped substrate. In this embodiment, only a P-type doped substrate is used as an example. It can be understood that an N-type doped substrate may also be used in another embodiment, which is not limited here.

[0059] As an example, the semiconductor substrate includes a chip area and a dicing area, and the pixel monitoring structure is disposed in the dicing area to reduce the wafer area occupied while meeting testing requirements.

[0060] like Figure 1 The diagram shown is a structural schematic of the image sensor charge signal interference monitoring device provided in this embodiment. Figure 1In the pixel monitoring structure, a P-type semiconductor substrate 100, a photoelectric conversion region (such as an N-type region 101 of a photodiode), a photodiode protective layer 102 (such as a P+ type PIN layer of a photodiode), a charge transport transistor 103, a floating diffusion active region 104, and a P-type semiconductor substrate 100. + The substrate contact area 105, the first isolation area 1061, the second isolation area 1062, and the third isolation area 1063.

[0061] In this configuration, one side of the photodiode, i.e., the right side of the N-type region 101 of the photodiode, is connected to the source terminal of the charge transport transistor 103. The drain terminal of the charge transport transistor 103 is the floating diffusion active region 104, and the floating diffusion active region 104 is in contact with the first isolation region 1061. The other side of the photodiode, i.e., the left side of the N-type region 101 of the photodiode, has a second isolation region 1062 and a third isolation region 1063, and the P-type region is disposed between the second isolation region 1062 and the third isolation region 1063. + Substrate contact area 105, the P + Both the substrate contact region 105 and the P-type semiconductor substrate 100 are P-type semiconductors, and the P-type semiconductor substrate 100 is a P-type semiconductor. + The substrate contact area 105 is grounded. In addition, each isolation region includes, but is not limited to, shallow trench isolation structures or ion-doped isolation regions.

[0062] The image sensor charge signal interference monitoring device includes an adjustable power supply 107 and a voltmeter 108. One end of the adjustable power supply 107 is connected to the N-type region 101 of the photodiode, and the other end is grounded. One end of the voltmeter 108 is connected to the floating diffusion active region 104, and the other end is grounded. In one embodiment, the first ion-doped protective layer has a contact opening, and the photoelectric conversion region is connected to the adjustable power supply via the contact opening. That is, in one example, the top of the N-type region 101 of the photodiode is provided with a contact opening, which is surrounded by the photodiode protective layer (P+PIN layer) 102; the N-type region 101 of the photodiode is connected to one end of the adjustable power supply 107 through the contact opening.

[0063] It should be noted that, in Figure 1 In the diagram, PD marks the connection between the N-type region 101 of the photodiode and the adjustable power supply 107, FD marks the connection between the floating diffusion active region 104 and the voltmeter 108, and TX-off marks the gate terminal of the charge transport transistor 103.

[0064] Furthermore, the photodiode N-type region 101, P... +Contact portions 109 are provided in the substrate contact area 105 and the floating diffusion active area 104, and an ohmic contact can be formed by forming a conductive metal in the contact portions 109. Of course, other existing methods can also be used to form the ohmic contact here.

[0065] As an example, the voltage regulation range of the adjustable power supply 107 may include -1V to 1V.

[0066] Specifically, when adjusting the adjustable power supply 107, it can be adjusted from negative voltage to positive voltage. The negative voltage can be between -1V and 0V, and the positive voltage can be between 0V and 1V. In this embodiment, the lowest negative voltage is -0.5V and the highest positive voltage is 0.5V. The types of the adjustable power supply 107 and the voltmeter 108 are not excessively limited here.

[0067] See Figures 2-4 This embodiment also provides a method for monitoring image sensor charge signal interference using the above-mentioned image sensor charge signal interference monitoring device, including the following steps:

[0068] S1: Provides a device for monitoring the charge signal interference of the image sensor;

[0069] S2: Set the charge transfer transistor 103 to the off state;

[0070] S3: Adjust the voltage of the adjustable power supply 107 and obtain the reading value of the voltmeter 108;

[0071] S4: Perform data analysis on the readings of the voltmeter 108 to obtain the charge signal interference information of the image sensor.

[0072] Specifically, the charge transfer transistor 103 is set to the off state, i.e., TX-off is set to low voltage. The adjustable power supply 107 scans from negative voltage to positive voltage, and during this process, the voltage change ΔU of the reading value of the voltmeter 108 is monitored. The negative voltage can be selected from -1V to 0V, and the positive voltage can be selected from 0V to 1V.

[0073] In this embodiment, the negative voltage is selected as -0.5V to 0V, and the positive voltage is selected as 0V to 0.5V, but the voltage adjustment range of the adjustable power supply 107 is not limited to these. When the voltage of the adjustable power supply 107 changes from negative voltage -0.5V to positive voltage 0.5V, the change in the voltage reading of the voltmeter 108 includes the following two cases:

[0074] The first variation pattern is that the voltage reading of the voltmeter 108 remains unchanged from its initial value. This result indicates that there is a path between the N-type region 101 of the photodiode and ground GND. After the photoelectric charge collected by the N-type region 101 of the photodiode is saturated, excessive photoelectric charge will overflow into the P-type semiconductor substrate 100, thereby affecting the accuracy of photoelectric signal acquisition in the surrounding neighboring pixel units, and thus causing charge signal interference.

[0075] like Figure 2 As shown, the potential well of the N-type region 101 of the photodiode is denoted as potential well 201, the potential well of the floating diffused active region 104 is denoted as potential well 202, and the P... + The potential well in the substrate contact region 105 is denoted as potential well 203. GND connects to potential well 203, PD connects to potential well 201, and FD connects to potential well 202. Figure 2 The isolation potential between the photodiodes of adjacent pixels is denoted as the isolation potential Viso, and the channel potential of the charge transfer transistor 103 is denoted as the channel potential Vof_1.

[0076] exist Figure 2 In the middle, the channel potential Vof_1 is lower than the isolation potential Viso. There is a path 21 between GND and PD. After the charge in the potential well 201 is saturated, it overflows. The photoelectric charge in the part with a potential lower than the isolation potential Viso is absorbed by the photodiode of the adjacent pixel unit. Since there is no path between PD and FD, the voltage change at the PD terminal is displayed as the isolation potential and will not affect the voltage reading value at the FD terminal. Therefore, the voltage reading value of the voltmeter 108 remains unchanged from the initial value.

[0077] In the second variation pattern, the initial value of the voltmeter 108 remains unchanged, then the reading increases, and finally the final value remains unchanged again. This indicates that a pathway exists between the N-type region 101 of the photodiode and the floating diffusion active region 104. After the N-type region 101 of the photodiode reaches saturation with photoelectric charge, the excess photoelectric charge overflows and is collected by the floating diffusion active region 104 through the pathway between the N-type region 101 and the floating diffusion active region 104, without affecting the accuracy of photoelectric signal acquisition in neighboring pixel units. Therefore, this method effectively eliminates the problem of charge signal interference.

[0078] like Figure 3As shown, the channel potential of the charge transfer transistor 103 is denoted as Vof_2. The channel potential Vof_2 is higher than the isolation potential Viso. There is a path 22 between PD and FD. After the charge in the potential well 201 is saturated, it overflows. The photoelectric charge in the part with a potential lower than the channel potential Vof_2 is attracted to the potential well 202 through the path 22. The voltage value of the FD terminal of the potential well 202 is related to the voltage value of the PD terminal. The voltage readout value of the FD terminal follows the change of the voltage value of the PD terminal.

[0079] exist Figure 3 In the process, the adjustable power supply 107 scans the PD terminal voltage. When the PD potential is lower than the isolation potential Viso, the FD voltage remains constant, which is the initial value read by the voltmeter 108. When the adjustable power supply 107 scans the PD terminal voltage, when the PD potential is higher than the isolation potential Viso and lower than the channel potential Vof_2, the FD voltage changes with the PD terminal voltage and is read by the voltmeter 108. When the adjustable power supply 107 scans the PD terminal voltage, when the PD potential is higher than the channel potential Vof_2, the FD voltage remains constant, which is the final value read by the voltmeter 108.

[0080] In this embodiment, the adjustable power supply 107 scans the PD terminal voltage, and the FD terminal voltage is read by the voltmeter 108. A schematic diagram illustrating the relationship between the first and second voltage variation patterns is shown below. Figure 4 .

[0081] exist Figure 4 In the diagram, the X-axis represents the voltage at the PD terminal scanned by the adjustable power supply 107, from -0.5V to 0.5V; the Y-axis represents the voltage at the FD terminal read by the voltmeter 108, where Viso is the initial value read by the voltmeter 108, and Vof_2a and Vof_2b are respectively... Figure 3 The channel potential of the charge transfer transistor 103 shown is marked as the final value read by the voltmeter 108.

[0082] exist Figure 4 In the diagram, curves 301 to 304 represent the following meanings:

[0083] Curve 304, (final value Viso displayed by the voltmeter - initial value Viso displayed by the voltmeter) = 0V, represents the first type of change pattern, which has a charge signal interference problem;

[0084] Curve 303 shows that (final value Vof_2a - initial value Viso) > 0V and (final value Vof_2a - initial value Viso) < 0.1V, indicating a minor charge signal interference issue.

[0085] Curve 302 shows that (final value Vof_2b - initial value Viso) > 0.1V and (final value Vof_2b - initial value Viso) < 0.3V, indicating no charge signal interference problem and that the charge signal saturation capacity of the photodiode is within the target range.

[0086] Curve 301, (final value Vof_2b - initial value Viso) > 0.3V, indicates no charge signal interference problem, but the charge signal saturation capacity of the photodiode is reduced too much and is outside the target range.

[0087] like Figure 4 As shown, products with measurement curves between 303 and 304 do not meet the target parameter requirements due to charge signal interference; products with measurement curves between 301 and 302 or outside of curve 301 do not meet the target parameter requirements because the charge signal capacity of the N-type region 101 of the photodiode is insufficient; products with measurement curves between 302 and 303 meet the target parameter requirements. Therefore, only products with measurement curves between 302 and 303 have good quality.

[0088] In summary, the image sensor charge signal interference monitoring device and method of the present invention, through the pixel monitoring structure, adjustable power supply, and voltmeter electrically connected in the image sensor charge signal interference monitoring device, can conveniently, efficiently, and accurately monitor charge signal interference problems of image sensors. It can be used in product mass production processes to monitor product parameter characteristics and quality stability. Furthermore, it can be used for evaluation and analysis before the product chip is completed, to promptly identify products that do not meet target standard parameters, conduct timely analysis and processing, find the causes, provide solutions, and reduce losses. Therefore, the image sensor charge signal interference monitoring device and method of the present invention can effectively save production costs and time costs.

[0089] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An image sensor charge signal interference monitoring device, characterized in that, The image sensor charge signal interference monitoring device includes: A pixel monitoring structure includes a semiconductor substrate, a charge transport transistor, and a photoelectric conversion region disposed in the semiconductor substrate. The semiconductor substrate includes a chip region and a dicing region. The pixel monitoring structure is disposed in the dicing region. One side of the photoelectric conversion region is connected to the source terminal of the charge transport transistor. The drain terminal of the charge transport transistor is a floating diffuse active region. A substrate contact region is also disposed in the semiconductor substrate. The substrate contact region has the same conductivity type as the semiconductor substrate and is grounded. An adjustable power supply, one end of which is connected to the photoelectric conversion area, and the other end of which is grounded; A voltmeter, one end of which is connected to the floating diffusion active region, and the other end of which is grounded.

2. The monitoring device according to claim 1, characterized in that: The semiconductor substrate is further provided with an isolation region, which includes a first isolation region, a second isolation region and a third isolation region. The first isolation region is located on the side of the floating diffusion active region away from the photoelectric conversion region. The second isolation region and the third isolation region are located on the side of the photoelectric conversion region away from the floating diffusion active region, and the substrate contact region is located between the second isolation region and the third isolation region.

3. The monitoring device according to claim 1, characterized in that: The voltage regulation range of the adjustable power supply includes -1V to 1V.

4. The monitoring device according to claim 1, characterized in that: The semiconductor substrate and the substrate contact region have a first ion doping type, the photoelectric conversion region has a second ion doping type, and the photoelectric conversion region is further provided with a first ion doping type protective layer. The first ion doping type protective layer has a contact opening, and the adjustable power supply is connected to the photoelectric conversion region through the contact opening.

5. The monitoring device according to claim 1, characterized in that: Contact portions are provided in the photoelectric conversion region, the substrate contact region, and the floating diffusion active region, and ohmic contacts are formed through the contact portions.

6. A method for monitoring charge signal interference in an image sensor, characterized in that, Includes the following steps: Provide an image sensor charge signal interference monitoring device according to any one of claims 1 to 5; Set the charge transfer transistor to the off state; Adjust the voltage of the adjustable power supply and obtain the reading value of the voltmeter; Data analysis is performed on the readings of the voltmeter to obtain the charge signal interference information of the image sensor.

7. The method for monitoring image sensor charge signal interference according to claim 6, characterized in that: The adjustable power supply scans the voltage from negative voltage to positive voltage.

8. The method for monitoring charge signal interference in an image sensor according to claim 6, characterized in that, The method for analyzing the readings of the voltmeter includes: when the obtained readings of the voltmeter remain unchanged from their initial values, the image sensor pixel unit exhibits charge signal interference.

9. The method for monitoring charge signal interference in an image sensor according to claim 6, characterized in that, The method for analyzing the readings of the voltmeter includes: When the initial reading of the voltmeter remains unchanged, then the reading increases, and finally the final reading remains unchanged, the final voltage value and the initial voltage value of the voltmeter are obtained, and the difference between the final voltage value and the initial voltage value is calculated to obtain the voltage change ΔU. When 0.1V > ΔU > 0V, there is a small amount of charge signal interference. When 0.3V > ΔU > 0.1V, there is no charge signal interference problem, and the charge signal saturation capacity of the photodiode is within the target range; When ΔU>0.3V, there is no charge signal interference problem, and the charge signal saturation capacity of the photodiode is reduced and is not within the target range.

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