CN115914780A - Camera module and manufacturing method thereof - Google Patents

Abstract

The present disclosure relates to a camera module and its manufacturing method. The camera module includes: a circuit board, including: a circuit board body with opposite front and back; The body of the circuit board; the first solder pad is arranged on the front or the back; and the first marking part and the second marking part are respectively arranged on the front and the back, and are used to identify The position of the first pad; and a photosensitive chip, the photosensitive surface of the photosensitive chip includes a photosensitive area and a non-photosensitive area, wherein the photosensitive chip includes a second pad arranged in the non-photosensitive area, wherein the The second pad is electrically connected to the first pad.

Description

Camera module and manufacturing method thereof

technical field

The present invention relates to the field of optical equipment, and more specifically, to a camera module and a manufacturing method thereof.

Background technique

With the rapid development of smart device technology in recent years, people pay more and more attention to the weight and volume of smart devices, and generally expect light weight or small volume to achieve the purpose of portability. As an image input device, the camera is widely used in camera shooting, mobile phone video, security monitoring, AR/VR and other fields, so the miniaturization of camera products also faces new challenges.

In the structural design of the existing camera module, gold wire bonding technology is usually used to realize the conduction between the chip and the circuit board, but the camera module manufactured in this way is relatively large in size. Furthermore, due to the limitation of the device size of ordinary camera modules, the product cannot be made smaller, resulting in a bottleneck in the miniaturization design of camera modules. Therefore, it is necessary to provide a new camera module design to meet the current requirements for high performance and small size of the camera module.

Contents of the invention

The present invention provides a camera module, including: a circuit board, the circuit board includes: a circuit board body, with opposite front and back; a light-through structure, passing through the circuit along the direction from the front to the back a board body; a first pad, disposed on the front side or the back side; and a first marking portion and a second marking portion, respectively disposed on the front side and the back side, for identifying the first pad position; and a photosensitive chip, the photosensitive surface of the photosensitive chip includes a photosensitive area and a non-photosensitive area, wherein the photosensitive chip includes a second pad arranged in the non-photosensitive area, wherein the second pad electrically connected to the first pad.

In one embodiment, the first marking part includes a first main marking point, and the second marking part includes a second main marking point; the first main marking point and the second main marking point are along the The direction from the front side to the back side is on the same axis.

In one embodiment, the light-through structure is a hole penetrating through the circuit board body.

In one embodiment, the area of the interface between the first pad and the second pad for electrical connection is at least two-thirds of the area of the second pad.

In one embodiment, the offset of the center of the first pad relative to the center of the second pad is less than or equal to one third of the width of the second pad.

In one embodiment, the offset is less than or equal to 15um.

In one embodiment, the width of the second pad is greater than or equal to 45um.

In one embodiment, the width of the second pad is greater than or equal to 88um.

In one embodiment, the first pad is electrically connected to the second pad through an anisotropic conductive glue.

In one embodiment, the circuit board is a printed circuit board.

In one embodiment, the camera module further includes a color filter disposed on the front surface and covering the light-transmitting structure.

In one embodiment, the camera module further includes components arranged on the front side.

In one embodiment, the camera module further includes a lens and a mirror seat arranged on the front surface, and the orthographic projection of the lens is located in the photosensitive area.

In the second aspect, the embodiment of the present application provides a method of manufacturing a camera module, the method includes: according to the first marking part located on the back of the circuit board, determine the first solder pad arranged on the back of the circuit board position, wherein the circuit board includes a light-transmitting structure passing through the circuit board body along the direction from the front to the back; the position of two welding pads; and electrically connecting the first welding pad and the second welding pad by controlling a first positional relationship between the first marking part and the center of the photosensitive area.

In one embodiment, the step of electrical connection includes: coating conductive glue at the first pad or the second pad; attaching the first pad and the second pad , wherein the conductive glue is located between the first pad and the second pad; and curing the conductive glue.

In one embodiment, the back of the circuit board is placed upward; the photosensitive chip is arranged on the circuit board, and the photosensitive surface of the photosensitive chip faces the back of the circuit board.

In one embodiment, after the step of electrical connection, it further includes: obtaining a second positional relationship between the center of the photosensitive area and the second marking portion arranged on the front side of the circuit board; according to the obtained The second positional relationship obtains an offset between the first pad and the second pad; and corrects the first positional relationship according to the obtained offset.

The present invention provides a miniaturized camera module, which realizes chip flip-mounting under the circuit board by means of high-precision positioning. The size of the camera module is small, and the structure is compact and the performance is stable.

Description of drawings

Other characteristics, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is a block flow diagram of a method for manufacturing a camera module according to an embodiment of the present application;

FIG. 2 is a block flow diagram of a method for manufacturing a camera module according to another embodiment of the present application;

3 is a schematic diagram of the back of a circuit board according to an embodiment of the present application;

4 is a schematic front view of a circuit board according to an embodiment of the present application;

5 is a schematic structural diagram of a photosensitive chip according to an embodiment of the present application;

6 is a schematic structural diagram of a second pad according to an embodiment of the present application; and

FIG. 7 is a schematic structural diagram of a camera module according to an embodiment of the present application.

Detailed ways

For a better understanding of the application, various aspects of the application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are descriptions of exemplary embodiments of the application only, and are not intended to limit the scope of the application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, expressions of first, second, third, etc. are only used to distinguish one feature from another, and do not represent any limitation on the features. For example, the first marking portion may also be referred to as the second marking portion.

In the drawings, the thickness, size and shape of components have been slightly adjusted for convenience of illustration. The drawings are examples only and are not strictly drawn to scale. For example, the thickness of the circuit board and the thickness of the photosensitive chip are not in proportion to actual production. As used herein, the words "approximately," "approximately," and similar words are used as words of approximation, not of degree, and are intended to describe measurements that would be recognized by those of ordinary skill in the art. Or inherent bias in calculated values.

It should also be understood that the terms "comprising", "comprising", "having", "comprising" and/or "comprising", when used in this specification, mean that the stated features, elements and/or components are present. , but does not exclude the existence or addition of one or more other features, elements, components and/or combinations thereof. Furthermore, expressions such as "at least one of," when preceding a list of listed features, modify the entire listed feature and do not modify the individual elements of the list. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or illustration.

Unless otherwise defined, all terms (including engineering terms and scientific and technical terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that unless there is an explicit statement in this application, words defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings in the context of related technologies, and should not be idealized or overly Formal meaning interpretation.

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. In addition, unless explicitly defined or contradicted by the context, the specific steps included in the methods described in the present application are not necessarily limited to the recited order, but may be performed in any order or in parallel. The present application will be described in detail below with reference to the accompanying drawings and embodiments.

Fig. 1 is a flowchart of a method for manufacturing a camera module according to an embodiment of the present application. Referring to Fig. 1 , the method 1000 provided by the embodiment of the present application includes the following steps.

Step S101 , according to the first marking portion located on the back side of the circuit board, determine the position of the first soldering pad provided on the back side of the circuit board. The first marking portion and the first pad may be located on the same side of the circuit board body of the circuit board. The second marking part can be located on the other side of the circuit board body.

Step S102 , according to the center of the photosensitive area of the photosensitive chip, determine the position of the second pad disposed on the non-photosensitive area of the photosensitive chip.

Step S103, electrically connecting the first pad and the second pad. Specifically, the photosensitive area of the photosensitive chip faces the circuit board, that is, the photosensitive chip is flip-chip mounted on the circuit board. Further, by controlling the first positional relationship between the first marking part and the center of the photosensitive area, the photosensitive area of the photosensitive chip is located at the light-transmitting structure of the circuit board.

In an exemplary embodiment, the method 1000 further includes step S104, step S105 and step S106.

Step S104, obtaining a second positional relationship between the center of the photosensitive area and the second marking portion.

Step S105, obtaining an offset between the first pad and the second pad according to the obtained second positional relationship.

Step S106, modifying the first positional relationship according to the obtained offset.

The method of manufacturing the camera module is described in detail below.

Referring to FIG. 2 and FIG. 3 , the circuit board body 5 of the circuit board 500 includes a front side 51 and a back side 52 . The circuit board 500 includes a light passing structure 53 . The light-passing structure 53 can be located in the middle of the circuit board body 5 , which penetrates the circuit board body 5 along the thickness direction of the circuit board body 5 , and the light-passing structure 53 is used for passing light. Exemplarily, the light passing structure 53 is a through hole. In other embodiments, the light-transmitting structure 53 may include a light-transmitting material.

As shown in FIG. 3 , the circuit board 500 further includes a first pad 56 and a first marking portion 54 . Both the first pad 56 and the first marking portion 54 are disposed on the back side 52 of the circuit board body 5 . The number and arrangement positions of the first pads 56 can be designed according to the photosensitive chip to be assembled. The first marking portion 54 has a definite relative position relative to the first pad 56 , and the position of the first pad 56 can be determined through the first marking portion 54 . Exemplarily, the first marking part 54 may include a first main marking point 541 and a first auxiliary marking point 542 . Specifically, the first main marking point 541 and the first auxiliary marking point 542 may have preset positions in the XY plane, so as to determine the position of the first pad 56 in the XY plane. The XY plane is a reference plane parallel to the rear face 52 or the front face 51 .

As shown in FIG. 4 , the circuit board 500 further includes a second marking portion 55 . The second marking portion 55 is disposed on the front side 51 of the circuit board body 5 . The second marking portion 55 has a definite relative position with respect to the first pad 56 , and the position of the first pad 56 in the XY plane can also be determined through the second marking portion 55 . Exemplarily, the second marking part 55 includes a second main marking point 551 and a second auxiliary marking point 552 . Specifically, the second main marker point 551 and the second auxiliary marker point 552 may have preset positions in the XY plane.

Exemplarily, the positions of the first main marking point 541 and the second main marking point 551 are consistent in projected positions in a direction perpendicular to the circuit board 500 . In other words, the two are located on the same axis in the thickness direction of the circuit board 500 . However, those skilled in the art should understand that the first main marking point 541 and the second main marking point 551 can be set at the same position, and can also be set at different positions, as long as the predetermined conversion relationship is satisfied, through the first marking part 54 or It only needs that the second marking part 55 can be accurately positioned to the position of the first pad 56 . Generally, at least one pair of marking points on the surface of the circuit board are located in the diagonal direction of the circuit board, the relative distance is as far as possible, and they are asymmetrical about the center to prevent fooling.

The method 1000 provided in this application can be realized by using a CCD (Charge coupled Device) machine. The CCD machine includes a CCD camera, which can identify each part placed on the CCD machine and calculate the relative position of each part. Exemplarily, the CCD base can be used to identify the first marking part, the second marking part, the center of the photosensitive chip, etc. of the circuit board. The CCD machine table can also have an XYZ coordinate space mapped to the actual space, and then each part can be moved to a specified position in the actual space, and other operations can be realized.

Exemplarily, when using a CCD base station to implement the method provided in this application, the following specific steps may be included.

Step S101

In an exemplary embodiment, the circuit board 500 is placed on the CCD machine with the back side 52 facing upwards. Identify the first marking portion 54 of the wiring board 500 . Specifically, the positions of the first main marker point 541 and the first auxiliary marker point 542 are identified. Furthermore, the position of the first pad 56 in the XY plane can be determined according to the preset positional relationship between the first main marking point 541 and the first auxiliary marking point 542 relative to the first pad 56 in the XY plane.

Exemplarily, the circuit board 500 is a printed circuit board, which may be a rigid circuit board or a flexible circuit board. The printed circuit can be on the first side or the second side, or include multiple layers of circuitry. The front side 51 and the back side 52 of the circuit board 500 in the embodiment of the present application are not restrictions on the specific structure of the circuit board 500, but the side where the first pad 56 is set is called the back side, and the side where the lens mount assembly is to be set is called the back side. front.

Step S102

Specifically, the photosensitive chip 600 can be placed on the CCD machine first, and the center of the photosensitive area 61 of the photosensitive chip 600 can be identified. Referring to FIG. 5 , the center of the photosensitive area 61 of the photosensitive chip 600 also has a preset positional relationship with respect to the second pad 63 in the XY plane. Furthermore, according to the center of the photosensitive area 61 of the photosensitive chip 600 , the position of the second pad 63 disposed on the non-photosensitive area 62 of the photosensitive chip 600 can be determined.

Specifically, the photosensitive surface of the photosensitive chip 600 can be placed downward.

Step S103

Exemplarily, the step S103 may include a sub-step S1031 of coating the conductive glue on the first pad of the circuit board 500 . Sub-step S1031 may be performed after step S101. In other embodiments, conductive glue can be coated on the second pad of the photosensitive chip, or conductive glue can be coated on both the first pad and the second pad. Specifically, the conductive glue is an anisotropic conductive glue.

Further, step S103 also includes a sub-step S1032 of moving the photosensitive chip 600 to align the first bonding pad 56 with the second bonding pad 63 . Specifically, the plurality of first pads 56 and the plurality of second pads 63 are aligned one by one. At the same time, the center of the photosensitive area 61 can be roughly aligned with the center of the light-through structure 53 of the circuit board 500 .

Further, the step S103 also includes a sub-step S1033 , attaching the photosensitive chip 600 and the circuit board 500 , specifically, attaching the first bonding pad 56 and the second bonding pad 63 . Then, the conductive glue can be cured by heating, so as to realize the conduction between the photosensitive chip 600 and the circuit board 500 .

In an exemplary embodiment, the first pad is electrically connected to the second pad through anisotropic conductive film (ACF). ACF is characterized by being conductive in one direction and non-conductive in the other. Specifically, in sub-step S1031, the ACF can be coated so that the electrical conduction direction (Z axis) perpendicular to the circuit board 500 and the resistance characteristics parallel to the circuit board 500 (XY plane) have obvious differences, when Z When the difference between the axial on-resistance value and the XY-plane insulation resistance value exceeds a certain ratio, it can be called good conductive anisotropy. The main components of the ACF include resin adhesives and conductive particles. The conductive particles are used to connect the photosensitive chip 600 and the circuit board 500, and at the same time, it can avoid conduction and short circuit between two adjacent first pads 56, so that the first pad 56 can be connected only in the Z-axis direction. The first pad 56 and the second pad 63 conduct electricity.

In an exemplary embodiment, after heating and curing the anisotropic conductive adhesive, a fixed camera module can be obtained. Exemplarily, the photosensitive chip 600 may completely cover the first marking part 54 . For a batch of products to be manufactured, it is not easy to confirm the bonding quality between the two pads 56/63, and then after the first product of a certain batch is manufactured through steps S101 to S103, step S104 can be performed Go to step S106.

Specifically, the second positional relationship between the center of the photosensitive area 61 and the second marking portion 55 is obtained. The offset between the first pad 56 and the second pad 63 is obtained from the obtained second positional relationship. Based on the obtained shift amount, the first positional relationship between the first marking portion 54 and the center of the photosensitive area 63 is corrected.

Through the setting of the second marking part, after the camera module is manufactured, it can be judged whether the position between the first pad and the second pad in the camera module is aligned, or whether the position between the two pads is aligned. Whether the interface of electrical connection is qualified. Then, the camera module manufactured by the method can be corrected, so that the camera module manufactured by this method has a high pass rate and the working state of the camera module is good.

Step S104

A second positional relationship between the center of the photosensitive area and the second marking portion is obtained.

Ideally, the second positional relationship between the center of the photosensitive area 61 and the second marking portion 55 should be equal to the design value. The first positional relationship and the second positional relationship are equivalent, only the identified reference points are different. Correcting the first positional relationship is mainly to determine and adjust the placement position between the circuit board 500 and the photosensitive chip 600 as a benchmark for relative movement during assembly.

However, the equipment actually used to manufacture camera modules always has a certain movement deviation, so there is inevitably a chip attachment offset between the circuit board and the photosensitive chip that are matched based on the same reference. At the same time, there will be manufacturing errors in the process of manufacturing the circuit board, so the marking points on the circuit board 500 are inevitably within the range of the same alignment.

Step S105

The offset between the first pad 56 and the second pad 63 is obtained from the obtained second positional relationship.

In an exemplary embodiment, referring to FIG. 5 and FIG. 6 , the first pad 56 on the back side 52 of the circuit board 500 is electrically connected to the second pad 63 on the photosensitive surface of the photosensitive chip 600 in a one-to-one correspondence. Reliability requires that the interface 631 for electrical connection between the first pad 56 and the second pad 63 is at least 2/3 of the area of the second pad 63 .

In an exemplary embodiment, the center of the first pad 56 and the center of the second pad 63 are offset by no more than one third of the width (diameter) of the second pad 63 . Exemplarily, the chip attachment offset X2 caused by equipment movement deviation is ≤15um. Assuming that the width of the second pad on the photosensitive chip is X1, X1>3*X2 needs to be satisfied.

Further, the co-location of the marking points on the front and back of the circuit board is X3, where 0≤X3≤25um, then it is required:

It is calculated that 88um≤X1.

That is, the width of the second bonding pad 63 on the photosensitive chip 600 is more than 88 um, so as to meet the requirement of attaching offset of the photosensitive chip 600 , and is suitable for miniaturized products. In other embodiments, by strictly controlling the manufacturing error, X1 can be further extended to the range of 45um≤X1, which is beneficial to miniaturization.

In an exemplary embodiment, the method 1000 for manufacturing a camera module further includes the following steps: installing the components 400 on the circuit board 500 . For example, the components 400 can be installed on the circuit board 500 through SMT (Surface Mounted Technology), wherein the components 400 can include capacitors, resistors, and driver integrated circuits. Those skilled in the art can understand that the components 400 and the circuit board 500 can be collectively referred to as SMT semi-finished products. Exemplarily, this step can be performed before the step of electrically connecting the photosensitive chip 600 .

In the implementation manner of the present application, the photosensitive chip 600 can be flip-chipped on the SMT semi-finished product by using an anisotropic conductive adhesive to complete the die attach (DA) process. Those skilled in the art can understand that the photosensitive chip 600 and the SMT semi-finished product can be combined into a DA semi-finished product.

In an exemplary embodiment, the assembly of the camera module further includes the following steps: the color filter 300 may be pasted on the DA semi-finished product by glue. The lens 100 can be fixed on the mirror base 200 by threading, and the lens 100 and the mirror base 200 form a lens base assembly. The lens mount assembly can be fixed to the DA semi-finished product by glue. Here, those skilled in the art can understand that the lens mount assembly and the DA semi-finished product can be collectively referred to as COB (Chips on Board) semi-finished product. Exemplarily, the reinforcing plate 700 can also be installed on the COB semi-finished product by welding to complete the assembly of the finished product. Exemplarily, a camera module as shown in FIG. 7 can be obtained.

The method provided by the embodiment of the present application avoids the use of gold wire bonding technology to realize the electrical connection between the photosensitive chip and the circuit board. The reduction of the Y/Z three-dimensional size.

The embodiment of the present application adopts the design of marking points at the same position on the front and back of the circuit board, and the assembly precision is high. Furthermore, the design of the pad with a smaller width can be allowed, which is suitable for a camera module with a miniaturized design.

In another aspect, the present application provides a camera module. As shown in Figure 7. The camera module provided in this application may include a circuit board 500 and a photosensitive chip 600 .

The circuit board body 5 of the circuit board 500 includes a front side 51 and a back side 52 . The circuit board 500 includes a light passing structure 53 . The light-passing structure 53 can be located in the middle of the circuit board body 5 , which penetrates the circuit board body 5 along the thickness direction of the circuit board body 5 , and the light-passing structure 53 is used for passing light.

The photosensitive chip 600 is flip-chip mounted on the circuit board 500 . Specifically, the photosensitive chip 600 is located on the side of the back surface 52 of the circuit board 500 , and the photosensitive area 61 of the photosensitive chip 600 faces the circuit board 500 .

In an exemplary embodiment, the light-through structure 53 is used to expose the photosensitive region 61 of the photosensitive chip 600 so as to transmit light from the side where the front side 51 of the circuit board 500 is located. The photosensitive area 61 includes a plurality of neatly arranged pixel units, all of which can completely sense light, and the photosensitive chip 600 converts optical signals into electrical signals and processes the electrical signals.

The camera module provided in this embodiment can be electrically connected to the photosensitive chip and the circuit board without gold wire binding, which realizes the miniaturization of the camera module and has high assembly accuracy.

In an exemplary embodiment, referring to FIG. 1 , the camera module further includes a color filter 300 disposed on the front surface 51 of the circuit board 500 and covering the light-transmitting structure 53 . Specifically, the color filter 300 is fixed on the front surface 51 of the circuit board 500 by glue bonding. Optionally, the color filter 300 is an infrared cut filter.

In the traditional manufacturing process, the camera module also needs to install the color filter through the color filter holder. Specifically, electronic components such as capacitors and resistors can be mounted on the circuit board through the surface mount technology (SMT) process; then through the COB process, the photosensitive chip is electrically connected to the circuit board through gold wires; The film support is placed on the circuit board; finally, the lens and the motor are arranged on the circuit board or the color filter support to realize the assembly of the camera module.

The color filter of the camera module of the present application is directly bonded to the second side of the circuit board, and the components are installed on the front of the circuit board through the SMT process, and more specifically, they are arranged on the periphery of the color filter, which can improve the The utilization of the focal space, especially to ensure that the height of the back focus space is only limited by the height of one of the color filters or electronic components, thereby reducing the height of the back focus space to reduce the overall height of the camera module to achieve high performance and small size camera module.

The camera module also includes components 400 arranged on the front of the circuit board 500 , a lens 100 and a mirror holder 200 , and the orthographic projection of the lens 100 is located in the photosensitive area of the photosensitive chip 600 under the light-transmitting structure 53 . In an exemplary embodiment, component 400 includes a capacitor, a resistor, and a driver integrated circuit.

In an exemplary embodiment, a reinforcing plate 700 is bonded to the back of the photosensitive chip 600 . The reinforcing plate 700 can reinforce the mechanical strength of the photosensitive chip 600 to facilitate subsequent surface mounting operations.

The above description is only a preferred embodiment of the present application and an illustration of the applied technical principle. Those skilled in the art should understand that the scope of protection involved in this application is not limited to the technical solution formed by the specific combination of the above-mentioned technical features, and should also cover the technical solutions obtained by the above-mentioned technical features without departing from the technical concept. Other technical solutions formed by any combination of or equivalent features thereof. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions in this application.

Claims (10)

1. A camera module, characterized in that, comprising: circuit boards, including: a circuit board body having opposite fronts and backs; a light-passing structure penetrating through the circuit board body along the direction from the front to the back; a first pad disposed on the front side or the back side; and A first marking part and a second marking part are respectively provided on the front side and the back side, and are used to identify the position of the first pad; and A photosensitive chip, the photosensitive surface of the photosensitive chip includes a photosensitive area and a non-photosensitive area, wherein the photosensitive chip includes a second pad arranged in the non-photosensitive area, wherein the second pad is connected to the first pad A pad is electrically connected. 2. The camera module according to claim 1, wherein the first marking part comprises a first main marking point, and the second marking part comprises a second main marking point; The first main marking point and the second main marking point are located on the same axis along the direction from the front side to the back side. 3. The camera module according to claim 1, wherein the light passing structure is a hole penetrating through the circuit board body. 4. The camera module according to claim 1, wherein the area of the interface between the first pad and the second pad for electrical connection is at least the area of the second pad two-thirds of. 5. The camera module according to claim 1, wherein the offset of the center of the first pad relative to the center of the second pad is less than or equal to the width of the second pad one-third of. 6. The camera module according to claim 5, wherein the offset is less than or equal to 15um. 7. The camera module according to claim 1, wherein the width of the second pad is greater than or equal to 45um. 8. The camera module according to claim 7, wherein the width of the second pad is greater than or equal to 88um. 9. A method for manufacturing a camera module, comprising: According to the first marking portion located on the back side of the circuit board, determine the position of the first soldering pad provided on the back side of the circuit board, wherein the circuit board includes a through hole passing through the circuit board body along the direction from the front side to the back side light structure; determining the position of the second pad disposed on the non-photosensitive area of the photosensitive chip according to the center of the photosensitive area of the photosensitive chip; and The first pad and the second pad are electrically connected by controlling a first positional relationship between the first marking portion and the center of the photosensitive area. 10. The method according to claim 9, further comprising: after the step of electrically connecting: Obtaining a second positional relationship between the center of the photosensitive area and the second marking portion disposed on the front side of the circuit board; obtaining an offset between the first pad and the second pad according to the obtained second positional relationship; Correct the first positional relationship according to the obtained offset.

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