Camera module, composite substrate, photosensitive component and manufacturing method thereof

Abstract

The present invention relates to a composite substrate, which includes: a circuit board having a first surface for attaching a photosensitive chip and an opposite second surface; heat dissipation ribs provided on the second surface, at least a part of the heat dissipation ribs being located in an area overlapping with the chip attachment area; and a back molding part manufactured on the second surface by a molding process, and the back molding part, the heat dissipation ribs and the circuit board are integrated. The present invention also provides a corresponding photosensitive component, a camera module and a corresponding manufacturing method. The present invention can avoid or suppress the deformation of the photosensitive chip at the cost of a relatively small space size.

Description

Technical Field

[0001] The present invention relates to the technical field of camera modules, and more specifically, to a camera module, a composite substrate for a camera module, a photosensitive component, and a manufacturing method thereof. Background Art

[0002] With the popularization of mobile electronic devices, the related technologies of camera modules used in mobile electronic devices to help users obtain images (such as videos or pictures) have developed rapidly and advanced. In recent years, camera modules have been widely used in many fields such as medical, security, and industrial production.

[0003] To meet the increasingly broad market demands, high pixel count, large chip size, small size, and large aperture are irreversible development trends for existing camera modules. However, it is very difficult to meet the requirements of high pixel count, large chip size, small size, and large aperture in the same camera module. For example, first, the market has put forward higher and higher requirements for the imaging quality of camera modules. How to obtain higher imaging quality with a smaller volume of the camera module has become a major problem in the field of compact camera modules (such as camera modules for mobile phones), especially on the premise of the development trends of high pixel count, large aperture, and large chip size in the mobile phone industry; second, the compact development of mobile phones and the increase in the screen-to-body ratio of mobile phones have made the space available for the front camera module inside the mobile phone smaller and smaller; the number of rear camera modules is increasing, and the occupied area is also getting larger and larger, resulting in corresponding reduction in the sizes of other components of the mobile phone such as the battery size and the motherboard size. To avoid sacrificing other components, the market hopes that the volume of the rear camera module can be reduced, that is, small-size packaging can be achieved; third, with the popularization of high-pixel chips and the gradual improvement of functions such as video shooting, the power consumption and heat dissipation of the chips have become important issues that need to be solved during the design and manufacturing process of the module.

[0004] The above market demands are the development bottlenecks of the camera module packaging industry. The main reasons for the long-term failure to solve the above demands are analyzed as follows:

[0005] (1) High pixel count and large chip size: As the chip size has been gradually increasing, for example, chips with a pixel count above 48 million are common at present, and their size is 1 / 2 inch. In the future, the popularization of 1 / 1.7-inch chips and even larger-sized chips will lead to a rapid increase in chip size. However, since the photosensitive chip is relatively thinner than ordinary chips, with a thickness of only about 0.15 mm, large chips are more likely to have field curvature problems. At the same time, since the chip and the circuit board are generally connected by glue, the glue coating generally shows a shape of being lower around and higher in the middle, such as applying glue in a cross shape, resulting in a slight bulge in the middle of the chip. Moreover, when the chip is attached, since the suction nozzle picks up the chip from above, the chip will also form a curved shape with the periphery lower than the center. In addition, the coefficients of thermal expansion (CTE) of the products among the chip, glue, and circuit board are different. For example, the CTE of the chip is 6 ppm / °C, while that of the PCB is 14 ppm / °C. In the module assembly process, there is generally a baking process. Due to the different CTE coefficients of various materials, it will cause chip bending problems. And the currently commonly used rigid-flex boards in the industry have relatively serious warping due to the lamination process, which will also exacerbate the chip bending problem. And the above chip bending problems will cause chip field curvature problems in the final module imaging and ultimately affect the imaging quality.

[0006] Furthermore, in the current trend of device miniaturization, in the currently mainstream compact camera modules (such as camera modules used in mobile phones), most circuit boards tend not to add additional heat dissipation components to avoid increasing the size of the camera module. However, at the same time, the heat dissipation performance of the circuit board itself is not sufficient to meet the heat dissipation performance requirements of the module. On the other hand, currently, high-end camera modules have developed to 48 million pixels and above, and at the same time, the demand for video shooting has gradually emerged, such as 4K high-definition video shooting, slow-motion capture, etc. In the future, there will be more high-pixel and high-frame-rate camera modules, and the power of the corresponding photosensitive chips has been greatly improved. The inventor of this case has found through research that as the heat generated by the photosensitive chip during operation increases, this heat accumulation causes the photosensitive chip to deform, which is one of the important factors leading to a decline in imaging quality. Specifically, in the working state, as the temperature inside the camera module rises, the circuit board and the photosensitive chip will bend, thereby reducing the imaging quality. In other words, for high-pixel and high-frame-rate photosensitive chips, even without being encapsulated by molding, they will be affected by temperature and bend. That is, whether encapsulated by molding or non-molding, the bending problem of high-pixel and large chips cannot be solved.

[0007] (2) Miniaturization / small size: In the field of compact camera modules, in order to reduce the size of the camera module and improve manufacturing efficiency, a molding process is adopted to directly form a bracket for the lens assembly or other components on the circuit board (such as MOB or MOC process solutions). Specifically, the camera module may include a photosensitive component and a lens assembly, and the lens group and other optical elements of the lens assembly are arranged on the photosensitive path of the photosensitive element (usually a photosensitive chip) of the photosensitive component. It should be noted that in some solutions, the color filter can be directly installed on the photosensitive component to form a part of the photosensitive component, but in other solutions, the photosensitive component may not contain a color filter, but the color filter is made into an independent color filter assembly or installed in other forms on the light-transmitting path. Therefore, the lens assembly can sometimes be understood as a combination of light-transmitting elements such as a lens group, a color filter and their supporting structural parts. This combination can sometimes also be called a light-transmitting component. Canceling or lowering the position of the color filter can further reduce the height of the module.

[0008] Furthermore, the photosensitive component may include a circuit board and a molded body integrally molded on the circuit board. Since the molded body eliminates the advantage of the avoidance space of the traditional lens holder attached module, the advantages of the module in terms of length, width and height can be further realized. In addition, the molded body can reinforce the strength of the circuit board, and can reduce the thickness requirement of the circuit board while ensuring the flatness of the module, so the circuit board can be thinned. For example, in the MOC packaging process, the photosensitive element is pre-attached to the circuit board, and then a molded body is formed on the circuit board through a molding process. The molded body can wrap part of the non-photosensitive area of the photosensitive element. In the camera module, the combination of the circuit board and the molded body, and the combination of the molded body and the photosensitive chip are both rigid combinations. This combination is very strong and often requires destructive methods to be removed. But at the same time, the circuit board and the photosensitive chip are combined by glue, which is a relatively flexible combination. In addition, the coefficients of thermal expansion (CTE) of the circuit board, molded body, and photosensitive chip differ. When the ambient temperature fluctuates significantly during the manufacturing process (for example, the molding process requires the temperature to be raised to above 150 degrees Celsius for molding the molding material, and the module baking stage requires the temperature to be raised to above 80 degrees Celsius. In the subsequent manufacturing process of the camera module, the ambient temperature may also change multiple times). The circuit board, chip, and molded body will expand to different degrees and at different rates. Among them, the photosensitive chip tends to shrink the least. However, because the connection between the circuit board and the molded body is a rigid connection, the circuit board and the molded body will generate stress, causing the circuit board and the molded body to bend. This bending will cause the photosensitive chip to deform. In particular, the upward bending of the photosensitive chip will lead to a significant decrease in the imaging quality of the module. Figure 24 The schematic diagram shows the principle of the deformation of the photosensitive chip caused by the bending of the circuit board and the mold body. Figure 24The illustration is exaggerated. In fact, the bending amount may only be a dozen to two dozen micrometers, but this degree of bending is sufficient to have a negative impact on the imaging quality. For example, such bending may cause excessive field curvature of the camera module. At this time, the image obtained by imaging of the camera module shows normal central effect but poor peripheral effect.

[0009] (3) Large aperture

[0010] Due to the popularization of large-pixel chips, the corresponding improvement in optical performance is an inevitable trend. For example, lens optical parameters such as large aperture and large wide angle will be gradually improved to maximize the resolution performance of the photosensitive chip. However, large-aperture and large-wide-angle modules have higher requirements for the flatness of the module.

[0011] Therefore, there is an urgent need for a solution that can avoid or suppress the deformation of the photosensitive chip at the cost of a smaller space size, and there is also an urgent need for a solution that can ensure the imaging quality of the camera module (especially the imaging quality in the long-term working state) at the cost of a smaller space size. Summary of the Invention

[0012] The object of the present invention is to overcome the deficiencies of the prior art and provide a solution for a camera module, a composite substrate for the camera module, and a photosensitive component.

[0013] To solve the above technical problems, the present invention provides a composite substrate for a camera module, the composite substrate comprising: a circuit board having a first surface and a second surface opposite to the first surface, wherein the first surface has a chip attachment area for attaching a photosensitive chip; heat dissipation ribs disposed on the second surface of the circuit board, at least a part of the heat dissipation ribs being located in an area overlapping with the chip attachment area; and a back molding part formed on the second surface by a molding process, and the back molding part, the heat dissipation ribs and the circuit board being integrated.

[0014] Wherein, the thickness of the heat dissipation ribs is not greater than 0.1 mm.

[0015] Wherein, the thickness of the back molding part is not greater than 0.2 mm.

[0016] Wherein, the heat dissipation ribs are directly formed on the second surface or attached to the second surface, and the back molding part covers the second surface and fills the gaps between the heat dissipation ribs, wherein the gaps between the heat dissipation ribs are the gaps between multiple heat dissipation ribs or the gaps between different parts of a single heat dissipation rib.

[0017] Among them, the heat dissipation ribs are multiple straight strip-shaped heat dissipation ribs arranged in parallel; or multiple heat dissipation ribs arranged in a scatter point array; or a single strip-shaped heat dissipation rib, and the single strip-shaped heat dissipation rib is spiral or "rice" shaped, or other strip shapes that can be connected into one body but still have gaps between different parts; or the heat dissipation ribs are any combination of two or more of the above items.

[0018] Among them, the heat dissipation ribs are metal heat dissipation ribs or heat dissipation ribs formed by hardening of a thermally conductive colloidal substance.

[0019] Among them, the photosensitive component further includes a secondary heat dissipation part. The top surface of the secondary heat dissipation part is connected to the bottom surface of the heat dissipation rib. The bottom surface of the back molding part is flush with the bottom surface of the secondary heat dissipation part. The bottom surface of the secondary heat dissipation part is exposed outside the back molding part, and the area of the bottom surface of the secondary heat dissipation part is larger than the area of the bottom surface of the heat dissipation rib.

[0020] Among them, the back molding part covers the bottom surface of the heat dissipation rib.

[0021] Among them, the heat dissipation rib is attached to the second surface by bonding or welding.

[0022] Among them, the root of the heat dissipation rib extends into the interior of the circuit board.

[0023] Among them, the circuit board is a multilayer board. The multilayer board includes a plurality of conductive layers and a plurality of insulating layers arranged at intervals, and the conductive layers and the insulating layers are combined together by a lamination process.

[0024] According to another aspect of the present application, there is also provided a photosensitive component, which includes: any one of the foregoing composite substrates; a photosensitive chip, the bottom surface of which is attached to the chip attachment area of the composite substrate; and metal wires, which electrically connect the photosensitive chip and the circuit board through a wire bonding process.

[0025] Among them, the photosensitive component further includes a front molding part. The front molding part is made on the first surface by a molding process and surrounds the photosensitive chip, and the top surface of the front molding part is suitable for mounting a lens assembly; there is a gap between the front molding part and the photosensitive chip, or the front molding part extends towards the photosensitive chip and contacts the photosensitive chip.

[0026] Among them, the photosensitive component further includes a lens bracket. The lens bracket is mounted on the first surface and surrounds the photosensitive chip, and the top surface of the lens bracket is suitable for mounting a lens assembly; the lens bracket is mounted on the first surface after being formed.

[0027] Among them, the photosensitive component further includes a lens holder, the lens holder is mounted on the front molding part, and the top surface of the lens holder is suitable for mounting a lens component; wherein the lens holder is mounted on the front molding part after being molded.

[0028] According to another aspect of the present application, there is also provided an imaging module, which includes: any one of the foregoing photosensitive components; and a lens component, the lens component is mounted on the photosensitive component.

[0029] According to another aspect of the present application, there is also provided a method for manufacturing a composite substrate, which includes: 1) preparing a circuit board, the circuit board has a first surface and a second surface opposite to the first surface, wherein the first surface has a chip attachment area for attaching a photosensitive chip, and the thickness of the circuit board is not greater than 0.3 mm; 2) arranging heat dissipation ribs on the second surface, at least a part of the heat dissipation ribs is located in an area overlapping with the chip attachment area; and 3) manufacturing a back molding part on the second surface through a molding process, the back molding part covers the second surface and fills the gaps between the heat dissipation ribs, so that the back molding part, the heat dissipation ribs and the circuit board are combined into one body, wherein the gaps between the heat dissipation ribs are the gaps between multiple heat dissipation ribs or the gaps between different parts of a single heat dissipation rib.

[0030] Among them, in the step 2), the heat dissipation ribs are attached by welding or bonding, and the thickness of the heat dissipation ribs is not greater than 0.1 mm.

[0031] Among them, in the step 1), the circuit board has a seed layer, and in the step 2), a metal layer is plated on the seed layer so that the metal layer grows and extends beyond the second surface, thereby forming the heat dissipation ribs; the thickness of the metal layer extending beyond the second surface is not greater than 0.1 mm.

[0032] Among them, in the step 2), a thermally conductive colloidal substance is coated on the second surface, and then the thermally conductive colloidal substance is hardened, thereby forming the heat dissipation ribs, and the thickness of the heat dissipation ribs is not greater than 0.1 mm.

[0033] According to another aspect of the present application, there is also provided a method for manufacturing a photosensitive component, which includes: manufacturing a composite substrate by any one of the foregoing methods for manufacturing a composite substrate; the method for manufacturing a photosensitive component further includes: 4) attaching a photosensitive chip on the first surface of the circuit board, installing electronic components, and electrically connecting the circuit board and the photosensitive chip through a wire bonding process.

[0034] Among them, the step 4) further includes: fabricating a front molding portion on the first surface, the front molding portion being fabricated on the first surface by a molding process and surrounding the photosensitive chip, and the top surface of the front molding portion being adapted to mount a lens assembly.

[0035] Among them, in the step 3) and the step 4), the front molding portion and the back molding portion are simultaneously formed on the circuit board by the same molding process.

[0036] Among them, the step 4) further includes: mounting a pre-formed lens holder on the first surface, the lens holder surrounding the photosensitive chip.

[0037] Compared with the prior art, the present application has at least one of the following technical effects:

[0038] 1. The photosensitive component and the camera module of the present application can avoid or suppress the deformation of the photosensitive chip at the cost of a smaller space size.

[0039] 2. The photosensitive component and the camera module of the present application improve the structural strength of the circuit board.

[0040] 3. The photosensitive component and the camera module of the present application improve the heat dissipation efficiency of the photosensitive chip.

[0041] 4. The photosensitive component and the camera module of the present application can ensure the imaging quality of the camera module at the cost of a smaller space size.

[0042] 5. The photosensitive component and the camera module of the present application are particularly suitable for camera modules with high pixels and high frame rates.

[0043] 6. The photosensitive component and the camera module of the present application are particularly suitable for combination with MOC and MOB technologies.

[0044] 7. The photosensitive component and the camera module of the present application can reduce the radial size of the camera module by arranging some electronic components on the back of the circuit board, and the radial size refers to the size in the direction perpendicular to the optical axis.

[0045] 8. The back of the photosensitive component of the present application can be a flat surface, which is convenient for subsequent manufacturing processes and is convenient for adapting to other components of the terminal device (such as a mobile phone).

[0046] 9. The back of the photosensitive component of the present application can be a flat surface, which is more suitable for mass production.

[0047] 10. The photosensitive component and the camera module of the present application have high production efficiency.

[0048] 11. In the photosensitive component of the present application, the back heat dissipation ribs are combined with the encapsulation part. On the one hand, the structural strength of the circuit board is improved, and on the other hand, the heat dissipation efficiency of the photosensitive chip is improved, avoiding rapid heat accumulation, reducing the stress that causes the circuit board to bend due to different coefficients of thermal expansion. Therefore, the photosensitive component of the present application can inhibit the bending of the photosensitive chip from two aspects.

[0049] 12. The photosensitive component of the present application can inhibit the bending of the photosensitive chip by avoiding rapid heat accumulation and increasing the structural strength. Therefore, the thickness of the encapsulation part and the heat dissipation ribs on the back of the circuit board can be relatively reduced. In other words, the present application can achieve the effect of inhibiting the bending of the photosensitive chip at a smaller thickness cost. Brief Description of the Drawings

[0050] Figure 1 Shows a cross-sectional schematic view of a composite substrate 1000 for a camera module in an embodiment of the present application;

[0051] Figure 2 Shows Figure 1 A three-dimensional schematic view of the composite substrate 1000 shown;

[0052] Figure 3 Shows a front schematic view of the composite substrate 1000 with a photosensitive chip 50 installed in an embodiment of the present application;

[0053] Figure 4 Shows a cross-sectional schematic view of a photosensitive component 2000 including the composite substrate 1000 in an embodiment of the present application;

[0054] Figure 5 Shows a back schematic view of the composite substrate in a modified embodiment of the present application;

[0055] Figure 6 Shows a back schematic view of the composite substrate in another modified embodiment of the present application;

[0056] Figure 7 Shows a photosensitive component 2000 based on the composite substrate in another embodiment of the present application;

[0057] Figure 8 Shows a photosensitive component 2000 based on the composite substrate in yet another embodiment of the present application;

[0058] Figure 9 Shows a cross-sectional schematic view of a photosensitive component in a further modified embodiment of the present application;

[0059] Figure 10 Shows a cross-sectional schematic view of a photosensitive component in a modified embodiment of the present application;

[0060] Figure 11Shows the circuit board 10 in step S10;

[0061] Figure 12 Shows a schematic diagram of manufacturing the heat dissipation ribs 20 on the second surface 15 of the circuit board 10 in step S20;

[0062] Figure 13 Shows a schematic diagram of placing the circuit board 10 in a mold to form a molding cavity in step S30 of an embodiment of the present application;

[0063] Figure 14 Shows a schematic diagram of injecting a liquid molding material into the molding cavity and molding it into the encapsulation part 30 in an embodiment of the present application;

[0064] Figure 15 Shows the composite substrate obtained after mold opening, which includes the circuit board 10, the heat dissipation ribs 20, and the encapsulation part 30;

[0065] Figure 16A Shows a circuit board panel with a connector part;

[0066] Figure 16B Shows a circuit board panel without a connector part;

[0067] Figure 17 Shows a schematic diagram of forming a molding cavity after mold closing in step S30 of an embodiment of the present application;

[0068] Figure 18 Shows a schematic diagram after molding in step S30 of an embodiment of the present application;

[0069] Figure 19 Shows a schematic diagram after mold opening in step S30 of an embodiment of the present application;

[0070] Figure 20 Shows a schematic diagram of forming a molding cavity after mold closing in step S31 of an embodiment of the present application;

[0071] Figure 21 Shows a schematic diagram after molding in step S31 of an embodiment of the present application;

[0072] Figure 22 Shows a schematic diagram after mold opening in step S31 of an embodiment of the present application;

[0073] Figure 23 Shows a composite substrate with a heat dissipation extension part in an embodiment of the present application;

[0074] Figure 24 Shows a schematic diagram of the principle of deformation of the photosensitive chip caused by bending of the circuit board and the molding body;

[0075] Figure 25 A cross-sectional schematic diagram of a camera module in one embodiment of the present application is shown;

[0076] Figure 26 A cross-sectional schematic diagram of a camera module in another embodiment of the present application is shown;

[0077] Figure 27 FIG2 shows a cross-sectional schematic diagram of a camera module in another embodiment of the present application;

[0078] Figure 28 FIG2 shows a cross-sectional schematic diagram of a camera module in another embodiment of the present application;

[0079] Figure 29 FIG2 shows a cross-sectional schematic diagram of a camera module in another embodiment of the present application;

[0080] Figure 30 FIG2 shows a cross-sectional schematic diagram of a camera module in another embodiment of the present application;

[0081] Figure 31 FIG2 shows a cross-sectional schematic diagram of a camera module in another embodiment of the present application;

[0082] Figure 32 FIG2 shows a cross-sectional schematic diagram of a composite substrate 1000 in another embodiment of the present application;

[0083] Figure 33 A schematic diagram showing placing the circuit board 10 in a mold to form a molding cavity in step S30 in another embodiment of the present application is shown;

[0084] Figure 34 A schematic diagram showing another embodiment of the present application of injecting liquid molding material into a molding cavity to form a packaging portion 30 is shown. DETAILED DESCRIPTION

[0085] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present 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.

[0086] It should be noted that in this specification, the expressions of first, second, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of this application, the first subject discussed below can also be referred to as the second subject.

[0087] In the drawings, for the sake of clarity, the thickness, dimensions and shape of the objects have been slightly exaggerated. The drawings are for illustrative purposes only and are not drawn to an exact scale.

[0088] It should also be understood that the terms "comprises", "comprising", "has", "including" and / or "including" when used in this specification denote the presence of the 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 combinations thereof. Further, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of listed features and not individual elements in the list. Further, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to refer to an example or illustration.

[0089] As used herein, the terms "substantially", "about" and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0090] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0091] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.

[0092] As described above, as the mobile phone camera module develops towards high pixels and high frame rates, the heat generated during the operation of the photosensitive chip is increasing. The inventors of this case have found through research that the superposition of factors such as heat accumulation and the increase in the size of the photosensitive chip (high pixels lead to an increase in the size of the photosensitive chip) makes the photosensitive chip prone to deformation, and this deformation is sufficient to cause a decline in the imaging quality of the camera module. Specifically, under the current development trend of the mobile phone market (mobile phone camera module market), first, the photosensitive chip itself has a large area and high power, generating a large amount of heat; second, the photosensitive chip has a large area and a small thickness, and this ratio makes the chip itself vulnerable to external objects; third, the photosensitive chip is affected by external objects such as the force generated by the circuit board and the molding deformation, making the photosensitive chip more prone to deformation. Based on this, the applicant proposes a composite substrate that can suppress the above-mentioned deformation, as well as a photosensitive component and a camera module based on the composite substrate. The present application will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0093] Figure 1 Shows a cross-sectional schematic view of a composite substrate 1000 for a camera module in an embodiment of the present application. Refer to Figure 1 , in this embodiment, the composite substrate 1000 includes a circuit board 10, heat dissipation ribs 20, and a back encapsulation part 30. The circuit board 10 has a first surface 14 for attaching a photosensitive chip and a second surface 15 opposite to the first surface 14. The heat dissipation ribs 20 are directly fabricated on the second surface 15. The material for fabricating the heat dissipation ribs has good thermal conductivity. In this embodiment, the thermal conductivity coefficient of the material used for the heat dissipation ribs is between 10 - 1000 W / mK, and the specific material can be copper, aluminum, silver, metal alloy, thermal conductive silicone grease, or other materials. The back encapsulation part 30 covers the second surface 15 and fills the gaps between the heat dissipation ribs 20. Further, Figure 2 Shows Figure 1 A three-dimensional schematic view of the composite substrate 1000 shown in Figure 2 . The circuit board 10 may include a circuit board body 11, a connector 12, and a flexible connection band 13. Figure 1 Only the circuit board body 11 is shown in . In this embodiment, the heat dissipation ribs 20 are actually attached to the back of the circuit board body 11, so the connector 12 and the flexible connection band 13 are omitted in some drawings. In this embodiment, the circuit board body 11 may be a PCB board. The heat dissipation ribs 20 are multiple straight strip-shaped heat dissipation ribs 21 arranged in parallel. Correspondingly, the back encapsulation part 30 fills the gaps between the multiple straight strip-shaped heat dissipation ribs 21 arranged in parallel and covers the second surface 15. For the sake of clear illustration, Figure 2 the back encapsulation part 30 and the circuit board 10 are shown separately in . The back encapsulation part 30 can be fabricated on the second surface 15 through a molding process. Of course, in other embodiments, the back encapsulation part 30 can also be realized by other encapsulation processes such as injection molding and compression molding, as long as it can cover the second surface 15 and fill the gaps between the heat dissipation ribs 20 to achieve encapsulation.

[0094] Here, based on different encapsulation methods, the setting of the back encapsulation part is based on different encapsulation processes, and there are different requirements for the setting of its heat dissipation ribs. If it is processed by the transfer molding method, since it is necessary to press the surface of the circuit board by a mold to form a runner, the direction of the heat dissipation ribs is preferably parallel to the molding press edge (i.e., the exposed edge of the circuit board), or at a certain angle, such as at an angle of 45 degrees or less than 45 degrees with the press edge, so as to facilitate the injection of the molding fluid and prevent the occurrence of "short shot" situations. The compression molding process mainly encapsulates through molding powder, and there is a certain gap in the surface flatness of the compression molding encapsulation compared with the molding encapsulation.

[0095] Further, Figure 3Shows a front schematic view of the composite substrate 1000 for mounting the photosensitive chip 50 in an embodiment of the present application. For ease of understanding, in this article, the side facing the photosensitive surface is uniformly referred to as the front, and the side facing away from the photosensitive surface is referred to as the back. Refer to Figure 3 , in this embodiment, the photosensitive chip 50 is attached to the center of the circuit board 10. The area on the first surface 14 of the circuit board 10 for attaching the photosensitive chip 50 is called the chip attachment area. Further, Figure 4 Shows a cross-sectional schematic view of the photosensitive component 2000 including the composite substrate 1000 in an embodiment of the present application. With combined reference to Figure 3 and Figure 4 , it can be seen that in this embodiment, a part of the heat dissipation ribs 20 is located in the area on the second surface corresponding to the back of the chip attachment area. Among them, a part of the linear strip-shaped heat dissipation ribs 21 is located in the area on the back of the chip attachment area, and both ends of these linear strip-shaped heat dissipation ribs 21 extend to the part outside the chip attachment area. Another part of the linear strip-shaped heat dissipation ribs 21 is located in the edge area of the circuit board 10, that is, this part of the linear strip-shaped heat dissipation ribs 21 is all located outside the chip attachment area. In this embodiment, since at least a part of the heat dissipation ribs 20 is arranged in the area overlapping with the photosensitive chip, the distance between the photosensitive chip and the heat dissipation ribs can be shortened, and the heat dissipation efficiency can be increased. In this embodiment, the bottom surface of the heat dissipation ribs is exposed outside the back encapsulation part to facilitate improving the heat dissipation effect. In this embodiment, the back heat dissipation ribs are combined with the encapsulation part. On the one hand, the structural strength of the circuit board is improved, and on the other hand, the heat dissipation efficiency of the photosensitive chip is improved, avoiding too fast heat accumulation, and reducing the stress caused by different thermal expansion coefficients resulting in the bending of the circuit board. Therefore, the photosensitive component of the present application can inhibit the bending of the photosensitive chip from two aspects.

[0096] Further, still referring to Figure 1In one embodiment of the present application, the bottom surface of the back packaging portion is flush with the bottom surface of the heat dissipation rib. In this embodiment, the back of the photosensitive component can be a flat surface, which is convenient for the subsequent manufacturing process, convenient for adaptation to other components of the terminal device (such as a mobile phone), and more suitable for large-scale mass production. Furthermore, in this embodiment, the thickness of the heat dissipation rib 20 can be 0.05mm-0.4mm, ensuring that the strength of the photosensitive component can be effectively enhanced without increasing the thickness of the camera module too much, and the bending effect of the photosensitive chip can be suppressed by the dual effects of enhancing structural strength and improving heat dissipation, thereby effectively preventing the imaging quality of the camera module (such as field curvature performance) from decreasing. In addition, since the molded body can play the role of reinforcing the circuit board, the circuit board selected in this technical solution can be thinner than the circuit board of the conventional design solution, generally reducing the thickness of the circuit board by 0.1mm, so in some cases, the module height will not be increased. The thickness of conventional circuit boards is generally 0.35mm or above (for example, 0.35mm-0.45mm), while the thickness of the circuit boards of MOB modules can be less than 0.3mm, and ideally less than 0.25mm. It should be noted that in this embodiment, the thickness refers to the axial dimension, that is, the dimension in the direction of the optical axis of the camera module. The axial direction can also be understood as the normal direction of the photosensitive surface or the first surface. It should be noted that although in the above embodiment, the bottom surface of the back packaging portion is flush with the bottom surface of the heat dissipation rib, this application is not limited to this. For example Figure 32FIG. shows a cross-sectional schematic view of the composite substrate 1000 in another embodiment of the present application. In this embodiment, the back encapsulation portion 30 is a back molding portion directly formed on the second surface 15 (i.e., the back surface) of the circuit board through a molding process, and this back molding portion covers the bottom surface of the heat dissipation ribs 20, rather than being flush with the bottom surface of the heat dissipation ribs 20. This solution can help improve the product yield. Due to possible deficiencies in the incoming material consistency of the molding material, if a back encapsulation portion with a bottom surface flush with the heat dissipation ribs is directly fabricated during molding, problems such as an uneven molding bottom surface may sometimes be encountered. Therefore, in this embodiment, the back molding portion covers the bottom surface of the heat dissipation ribs 20, so that a bottom surface 38 entirely composed of the molding material can be obtained. This bottom surface 38 can have a very high flatness, the process difficulty is reduced, and the requirements for the quality of the molding material can be lowered, which is beneficial to improving the product yield and reducing production costs. Further, in an embodiment of the present application, on the basis that the back molding portion covers the second surface and the bottom surface of the heat dissipation ribs, the distance between the bottom surface 38 of the back molding portion and the bottom surface of the heat dissipation ribs may not be greater than 0.1 mm, and the distance between the bottom surface 38 of the back molding portion and the second surface 15 may not be greater than 0.2 mm (i.e., the thickness of the back molding portion is not greater than 0.2 mm). The composite substrate obtained in this way still has a relatively small thickness. Further, in an embodiment of the present application, when the back molding portion covers the second surface 15 and the bottom surface of the heat dissipation ribs 20, the thickness of the circuit board can be further reduced to 0.25 mm or less than 0.25 mm.

[0097] Further, still referring to Figure 3 , in an embodiment of the present application, the photosensitive chip 50 is rectangular, this rectangle has a long side L and a short side W, and the heat dissipation ribs 20 are composed of multiple parallel linear strip-shaped heat dissipation ribs. These multiple parallel linear strip-shaped heat dissipation ribs can be parallel to the long side L of the photosensitive chip 50. A typical photosensitive chip is a rectangle with an aspect ratio of 16:9, and the warping degrees of the chip along the long side and the short side are usually different. The arrangement direction of the heat dissipation ribs adopted in this embodiment is more conducive to suppressing and preventing the photosensitive chip from bending. Therefore, it is preferably to arrange the heat dissipation ribs along the direction parallel to the long side of the photosensitive chip.

[0098] In another embodiment of the present application, the circuit board 10 (actually referring to the circuit board main body 11) is rectangular, this rectangle has a long side and a short side, and multiple of the linear strip-shaped heat dissipation ribs are all parallel to the long side of the circuit board 10. The arrangement direction of the heat dissipation ribs adopted in this embodiment is more conducive to suppressing and preventing the photosensitive from bending. It should be noted that in Figure 3 , the long side direction of the photosensitive chip is the same as the long side direction of the circuit board, but the present application is not limited to this, because sometimes the long side of the photosensitive chip can be perpendicular to the long side of the circuit board.

[0099] Furthermore, Figure 5 FIG. shows a schematic view of the back surface of the composite substrate in a modified embodiment of the present application. Refer to Figure 5 , in this embodiment, the heat dissipation ribs 20 adopt another shape, that is, the heat dissipation ribs 20 are composed of a single strip-shaped heat dissipation rib connected integrally. In the upward viewing angle, the heat dissipation ribs 20 are generally in the shape of a "rice" character. At this time, the gap between the heat dissipation ribs can be understood as the gap between different parts of a single heat dissipation rib. The back surface encapsulation part 30 fills this gap to achieve encapsulation. This embodiment can strengthen the structural strength in the diagonal direction, horizontal direction, and vertical direction of the circuit board, support the circuit board in multiple directions, inhibit the warping of the four corners of the photosensitive component, strengthen the ability to prevent the photosensitive component from bending, and relieve the bending of the photosensitive component. In some cases, due to the concentrated coating of the glue (i.e., the adhesive material) inside the chip in the middle, or due to the chip being adsorbed from the upper part by the suction nozzle and attached to the circuit board, the chip is prone to bend upward at the center, and the degree of the above-mentioned bending may be aggravated in the subsequent manufacturing process. In a preferred embodiment of the present invention, for the heat dissipation ribs in the shape of a "rice" character, an "X" character, or a cross, the center position of the heat dissipation rib structure corresponds to the center area of the chip, and the center part of the chip is reinforced and fixed, which is beneficial to inhibiting the upward warping of the chip center and the warping of the four corners of the photosensitive component, thereby inhibiting the field curvature of the chip.

[0100] Furthermore, Figure 6 FIG. shows a schematic view of the back surface of the composite substrate in another modified embodiment of the present application. Refer to Figure 6 , in this embodiment, the heat dissipation ribs 20 adopt another shape, that is, the heat dissipation ribs 20 are composed of a single strip-shaped heat dissipation rib connected integrally. In the upward viewing angle, the heat dissipation ribs 20 are generally in the shape of a square helix. Similar to Figure 5 the embodiment of, in this embodiment, the gap between the heat dissipation ribs can be understood as the gap between different parts of a single heat dissipation rib. The back surface encapsulation part 30 fills this gap to achieve encapsulation. This embodiment can strengthen the structural strength of the circuit board, support the circuit board in multiple directions, strengthen the ability to prevent the photosensitive component from bending, and relieve the bending of the photosensitive component.

[0101] It should be noted that other shapes of heat dissipation ribs 20 can also be adopted in the present application, such as "X"-shaped heat dissipation ribs, "return"-shaped or annular heat dissipation ribs, etc. The heat dissipation ribs 20 can also be a plurality of small heat dissipation ribs arranged in a scattered dot array. The heat dissipation ribs 20 can also be a combination of two or more of the above, for example, on the back surface of the same circuit board, a plurality of parallel linear strip-shaped heat dissipation ribs and a "rice"-shaped heat dissipation rib can be provided simultaneously. Various combination methods can be set flexibly and will not be elaborated one by one herein.

[0102] Furthermore, in an embodiment of the present application, the heat dissipation ribs can be made of a metal material. For example, a multi-layer PCB board can be used as the circuit board. The multi-layer PCB board has multiple layers, and each layer can be arranged with circuits and designed functional circuits. Different layers can be electrically connected through copper pillars (or other metal pillars) to form an integral whole (electrically) of the entire circuit board. In this embodiment, a copper seed layer can be fabricated on a certain layer of the circuit board, and then copper pillars can be plated and grown on the seed layer by electroplating method to extend beyond the second surface (i.e., the back surface) of the circuit board, thereby forming the required heat dissipation ribs. In this embodiment, the manufacturing process of the heat dissipation ribs can be compatible with the process in circuit board manufacturing, which is easy to mass-produce, and the obtained composite substrate has a relatively high structural strength. The layer of the multi-layer PCB board used for fabricating the seed layer can be not used for circuit conduction, but dedicated to strengthening the structural strength of the circuit board.

[0103] In another embodiment of the present application, the heat dissipation ribs can be formed by a thermally conductive colloidal substance. For example, the thermally conductive colloidal substance can be coated on the second surface (i.e., the back surface) of the circuit board in the required shape, and then the thermally conductive colloidal substance is hardened to form the heat dissipation ribs. The thermally conductive colloidal substance can be, for example, thermally conductive silicone grease.

[0104] In yet another embodiment of the present application, the heat dissipation ribs can be pre-formed and then attached to the second surface (i.e., the back surface) of the circuit board by means of bonding or soldering. The pre-formed heat dissipation ribs can be made of a metal material or a hardened thermally conductive colloidal substance, such as thermally conductive silicone grease.

[0105] Furthermore, still referring to Figure 4 , according to an embodiment of the present application, a photosensitive component 2000 based on a composite substrate is provided. The photosensitive component 2000 includes a composite substrate. The composite substrate can include a circuit board 10, heat dissipation ribs 20, and a back encapsulation part 30. The photosensitive chip 40 is attached to the first surface 14 of the circuit board 10. The heat dissipation ribs 20 are directly fabricated on the second surface 15 of the circuit board 10. The back encapsulation part 30 covers the second surface 15 and fills the gaps between the heat dissipation ribs 20 to achieve an encapsulation effect. The photosensitive component 2000 further includes an electronic component 50, and the electronic component 50 can be mounted on the first surface 14 and arranged around the photosensitive chip 40. The electronic component 50 can be, for example, a passive device such as a capacitor component or an inductor component, or an active device such as a memory chip or an image processor chip. The photosensitive component can further include a metal wire 60, and the metal wire 60 can electrically connect the photosensitive chip and the circuit board through a wire bonding (its English name is Wire Bonding, and it can also be called "lead bonding", "bonding", "bonding", or "wire bonding") process. The metal wire 60 can be a metal wire with better conductivity such as a gold wire, an aluminum wire, or a copper wire.

[0106] Further, Figure 7 A photosensitive component 2000 based on a composite substrate according to another embodiment of the present application is shown. The difference between this embodiment and the previous embodiment (refer to Figure 4 ) is that the electronic component 50 is arranged on the back side of the circuit board 10, that is, the electronic component 50 is mounted on the second surface 15. The back encapsulation portion 30 can wrap the electronic component 50 or be filled around the electronic component 50, so as to realize the encapsulation on the back side of the circuit board. In this embodiment, since the electronic component can be arranged on the back side of the circuit board, the space on the front side of the circuit board for arranging the electronic component can be omitted, which helps to reduce the radial size of the photosensitive component. In this embodiment, the radial size refers to the size in the direction perpendicular to the optical axis of the imaging module. And the thickness direction of the circuit board can be called the axial direction, and this direction is parallel to the optical axis of the imaging module. It should be noted that all the electronic components can be arranged on the back side of the circuit board, or part of them can be arranged on the back side of the circuit board and the other part can be arranged on the front side of the circuit board.

[0107] Further, Figure 8 A photosensitive component 2000 based on a composite substrate according to still another embodiment of the present application is shown. Compared with Figure 4 the embodiment, the difference in this embodiment is that a secondary heat dissipation portion 22 is added. Among them, the top surface of the secondary heat dissipation portion 22 is connected to the bottom surface of the heat dissipation rib 20. The bottom surface of the back encapsulation portion 30 can be flush with the bottom surface of the secondary heat dissipation portion 22, and the bottom surface of the secondary heat dissipation portion 22 is exposed outside the back encapsulation portion 30. The area of the bottom surface of the secondary heat dissipation portion 22 is larger than the area of the bottom surface of the heat dissipation rib 20. This can increase the surface area of the heat dissipation member and improve the heat dissipation efficiency. It should be noted that Figure 8 what is shown is not the only implementation form of the secondary heat dissipation portion 22. For example, in another embodiment, the longitudinal section of the secondary heat dissipation portion 22 can be trapezoidal, so that the cross-sectional area of the secondary heat dissipation portion gradually increases from its top surface to the bottom surface. This implementation method can also increase the surface area of the heat dissipation member and improve the heat dissipation efficiency.

[0108] Further, Figure 9 A schematic cross-sectional view of a photosensitive component according to still another modified embodiment of the present application is shown. Referring to Figure 9 , in this embodiment, the back encapsulation portion of the photosensitive component is cancelled, that is, the heat dissipation rib 20 is made on (or attached to) the second surface (back side) of the circuit board 10. The bottom surface and the side surface of the heat dissipation rib 20 are both exposed. The heat dissipation rib 20 can be a plurality of linearly arranged strip-shaped heat dissipation ribs arranged in parallel, or a plurality of heat dissipation ribs arranged in a scattered dot array, or a single strip-shaped heat dissipation rib, and this single strip-shaped heat dissipation rib is spiral or "rice" shaped, or other strip-shaped shapes that can be connected into one body but still have gaps between different parts; it can also be any combination of the above two or more items.

[0109] Further, in an embodiment of the present application, the photosensitive component may further include a front molding portion, and the front molding portion may be fabricated on the first surface by a molding process and surround the photosensitive chip. In this embodiment, there is a gap between the front molding portion and the photosensitive chip, that is, the MOB process. Moreover, in this embodiment, the top surface of the front molding portion is adapted to mount a lens assembly. Here, the lens assembly may be a lens assembly with a motor or a lens assembly without a motor.

[0110] Further, in another embodiment of the present application, the photosensitive component may further include a front molding portion, and the front molding portion may be fabricated on the first surface by a molding process and surround the photosensitive chip and the front molding portion extends towards the photosensitive chip and contacts the photosensitive chip (for example, the front molding portion may cover the edge area of the photosensitive chip), that is, the MOC process. Moreover, in this embodiment, the top surface of the front molding portion is adapted to mount a lens assembly. Here, the lens assembly may be a lens assembly with a motor or a lens assembly without a motor. The lens assembly and the photosensitive component are assembled together to obtain an imaging module.

[0111] It should be noted that when the photosensitive component is encapsulated by the MOC process, since the molding body is integrally formed on the photosensitive chip, the photosensitive chip may be more prone to bending. For example, for a photosensitive component encapsulated by the MOC process, not only may the phenomenon of bending of the photosensitive chip occur after long-term use, but also the phenomenon of bending of the photosensitive chip may occur during the manufacturing process. For another example, for a photosensitive component encapsulated by the MOC or MOB process, not only may the photosensitive chip of a high-pixel and high-frame-rate imaging module bend after long-term use, but this bending phenomenon may also occur in an imaging module with relatively low pixel numbers and frame rates. This is because during the molding process, the temperature change in the manufacturing environment is relatively large (for example, it rises from room temperature to over 150 degrees and then drops back to room temperature), and the thermal expansion coefficients of the molding material and the circuit board are different, so stress is easily generated between the two, and the photosensitive component of the MOC / MOB module is more prone to bending. Therefore, for a photosensitive component encapsulated by the MOC / MOB process, setting the heat dissipation ribs in the previous embodiment on the back of the circuit board can achieve a more obvious effect in suppressing the bending of the photosensitive chip. Further, in combination with the molding body and the heat dissipation ribs, the requirement for the thickness of the circuit board can be reduced, and at the same time, good flatness can be achieved, and the heat dissipation performance is significantly improved compared with existing products.

[0112] Further, in another embodiment of the present application, the front molding portion can be replaced by a lens holder (which can sometimes also be referred to as a lens mount). After the lens holder is molded, it is then installed on the first surface. Specifically, the lens holder is installed on the first surface and surrounds the photosensitive chip, and the top surface of the lens holder is adapted to mount the lens assembly.

[0113] Further, in another embodiment of the present application, the photosensitive component may further include a color filter, which can be installed on the front molding portion or the lens holder. When the color filter is installed on the front molding portion, a stepped structure can be formed on the top surface of the front molding portion, and the color filter is installed on the stepped structure.

[0114] Further, in another embodiment of the present application, the photosensitive component may not include a color filter. A color filter assembly can be added to the camera module, and the color filter assembly includes a lens mount and a color filter installed on the lens mount. The photosensitive component may have a front molding portion, and the bottom of the lens mount is installed on the top surface of the front molding portion. The lens assembly is installed on the top surface of the lens mount.

[0115] It should be noted that in the above embodiments, the photosensitive chip is attached to the front side of the circuit board, that is, the first surface, but the present application is not limited thereto. In a modified embodiment, the center of the circuit board may have a main through hole for accommodating the photosensitive chip, and the photosensitive chip can be installed in the main through hole. This manufacturing process helps to reduce the axial dimension of the photosensitive component. That is, to reduce the dimension in the optical axis direction (referring to the optical axis of the camera module or the lens assembly). Figure 10 Shows a cross-sectional schematic view of the photosensitive component of a modified embodiment of the present application. Refer to Figure 10 It can be seen that in this embodiment, the circuit board and the photosensitive chip form a combination, wherein the side facing the photosensitive surface of the photosensitive chip is the front side of the combination, and the side opposite to the front side is the back side of the combination. The heat dissipation ribs are located on the back side of the combination, and the heat dissipation ribs are directly fabricated on or attached to the back side of the combination. And in this embodiment, the back side of the combination includes the back sides of the circuit board and the photosensitive chip, and at least a part of the heat dissipation ribs is located on the back side of the photosensitive chip.

[0116] Further, according to another embodiment of the present application, a method for manufacturing a photosensitive component is also provided, which includes the following steps S10 - S40 executed in sequence.

[0117] Step S10, prepare a circuit board 10. Figure 11The circuit board 10 in step S10 is shown. The circuit board 10 has a first surface 14 for attaching a photosensitive chip and a second surface 15 opposite the first surface 14, wherein the first surface 14 has a chip attachment area. The circuit board 10 in this step can be a PCB board, which can be made in-house or ordered on the market (note that there are currently no such products on the market. In other words, the structure of the circuit board 10 itself described in this step is not prior art). In this embodiment, the thickness of the circuit board is not greater than 0.3 mm.

[0118] In step S20 , heat dissipation ribs 20 are formed on the second surface 15 (ie, the back surface) of the circuit board 10 . Figure 12 FIG2 shows a schematic diagram of making heat dissipation ribs 20 on the second surface 15 of the circuit board 10 in step S20. At least a portion of the heat dissipation ribs 20 is located directly below the chip attachment area (note that Figure 12 The circuit board 10 is turned upside down, so Figure 12 The heat dissipation rib 20 is located above the circuit board 10), that is, the area on the second surface 15 that overlaps with the chip attachment area. In this embodiment, the heat dissipation rib 20 can be set to a preset shape. For example, the heat dissipation rib can be composed of a plurality of parallel straight strip heat dissipation ribs. In this embodiment, the thickness of the heat dissipation rib 20 can reach 0.1 mm or less. The thickness of the heat dissipation rib here refers to the dimension in the normal direction of the second surface, and the thickness of the heat dissipation rib is the dimension of the heat dissipation rib exceeding the second surface. If the root of the heat dissipation rib is located inside the circuit board, the portion located inside the circuit board is not counted in the thickness of the heat dissipation rib.

[0119] Step S30, covering the second surface with a backside encapsulation portion, wherein the backside encapsulation portion covers the second surface and fills the gaps between the heat dissipation ribs, wherein the gaps between the heat dissipation ribs are gaps between multiple heat dissipation ribs or gaps between different parts of a single heat dissipation rib; the bottom surface of the heat dissipation rib is exposed outside the backside encapsulation portion and the bottom surface of the backside encapsulation portion is flush with the bottom surface of the heat dissipation rib. In this embodiment, the backside encapsulation portion can be formed on the second surface by a molding process. Specifically, Figure 13 A schematic diagram of placing the circuit board 10 in a mold to form a molding cavity in step S30 in one embodiment of the present application is shown. Figure 14 FIG1 shows a schematic diagram of injecting liquid molding material into a molding cavity and molding the packaging portion 30 in one embodiment of the present application. Figure 13, place the circuit board 10 in a mold, which includes an upper mold 91 and a lower mold 92. The second surface 15 of the circuit board 10 faces upward, and heat dissipation ribs 20 are provided on the second surface 15. There are gaps between the heat dissipation ribs 20, and the bottom surface of the upper mold 91 presses on the end faces of the heat dissipation ribs 20, and the lower mold 92 abuts against the first surface 14 of the circuit board 10. After the upper and lower molds are closed, a molding cavity is formed among the upper mold 91, the circuit board 10, and the heat dissipation ribs 20. Then, refer to Figure 14 , in Figure 13 , inject a liquid molding material into the molding cavity, and the liquid molding material is cured and molded into a package portion 30. Further, Figure 15 shows the composite substrate obtained after the mold is opened. The composite substrate includes a circuit board 10, heat dissipation ribs 20, and a package portion 30. In this step, the thickness of the back molding portion made by the molding process can reach 0.1 mm or less than 0.1 mm. It should be noted that although the solution where the bottom surface of the back molding portion is flush with the bottom surface of the heat dissipation rib is adopted in the above embodiment, the present application is not limited thereto. For example, in another embodiment of the present application, the back molding portion can cover both the second surface 15 and the bottom surface of the heat dissipation rib 20 (refer to Figure 32 ). In this embodiment, a gap 39 can be left between the upper mold 91 and the bottom surface of the heat dissipation rib 20 (in Figure 13-14 , the bottom surface of the heat dissipation rib 20 faces upward) (refer to Figure 33 , Figure 33 shows a schematic diagram of placing the circuit board 10 in a mold to form a molding cavity in step S30 in another embodiment of the present application). The gap 39 can be 0.1 mm (it can also be other values, such as 0.06 mm, generally not greater than 0.1 mm). Further, Figure 34 shows a schematic diagram of injecting a liquid molding material into the molding cavity and molding it into a package portion 30 in another embodiment of the present application. Since there may be deficiencies in the material consistency of the molding material, if a back package portion with a bottom surface flush with the heat dissipation rib is directly made during molding, sometimes problems such as uneven molding bottom surface will be encountered. Making the back molding portion cover the bottom surface of the heat dissipation rib can obtain a bottom surface completely composed of the molding material. This bottom surface can have a very high flatness, and the process difficulty is reduced, and the requirement for the quality of the molding material can be lowered, which is beneficial to improving the product yield and reducing the production cost. Further, in an embodiment of the present application, when the back molding portion covers the second surface and the bottom surface of the heat dissipation rib, the thickness of the circuit board can be further reduced to 0.25 mm or less than 0.25 mm.

[0120] In step S40, a photosensitive chip and other components (such as electronic components, metal wires, lens holders, color filters, etc.) are mounted on the first surface (i.e., the front surface) of the circuit board to produce the photosensitive assembly. The photosensitive chip can be attached to the chip attachment area of the first surface.

[0121] Furthermore, in one embodiment, in step S20, the heat dissipation ribs can be directly formed on the second surface of the circuit board. For example, the circuit board can include a seed layer, and a metal layer can be implanted on the seed layer so that the metal layer grows beyond the second surface, thereby forming the heat dissipation ribs. For another example, in a variant embodiment, a thermally conductive colloid can be coated on the second surface and then hardened to form the heat dissipation ribs.

[0122] Furthermore, in another embodiment, the heat dissipation rib may be pre-formed and then attached to the second surface of the heat dissipation rib by welding or bonding.

[0123] In the above embodiments, heat dissipation ribs are first made and then molded to form the back packaging portion. However, the present application is not limited to this. For example, in another embodiment of the present application, another method for making a photosensitive component is provided. Different from the manufacturing method of the aforementioned embodiment, in this embodiment, the back packaging portion can be first molded on the back of the circuit board, and then the heat dissipation ribs can be made or attached to the second surface (i.e., the back) of the circuit board. Specifically, in this embodiment, the execution order of step S30 and step S20 is swapped, that is, step S30 is executed first and then step S20 is executed. In step S30, the back packaging portion can be formed on the second surface by a molding process, and during the molding process, a through hole can be left in the back packaging portion by using a pressure head (or a raised structure of an upper mold), and the through hole exposes a portion of the second surface outside the back packaging portion. Figure 17 FIG2 shows a schematic diagram of forming a molding cavity after mold closing in step S30 of an embodiment of the present application. Figure 17 It can be seen that the upper mold 91 has a plurality of downward protruding structures 93 , which press against the second surface 15 of the circuit board 10 , and a molding cavity surrounding the protruding structures 93 can be formed between the upper mold 91 and the circuit board 10 . Figure 18 FIG1 shows a schematic diagram of the molding process in step S30 of an embodiment of the present invention. Figure 18 It can be seen that the liquid molding material is injected into the molding cavity and solidified to obtain the backside encapsulation part 30 . Figure 18 As can be seen in FIG, the backside encapsulation portion 30 can surround the protruding structures 93, or the backside encapsulation portion 30 can fill the gaps between the protruding structures 93 and the gaps between the protruding structures 93 and the mold. Figure 19The figure shows a schematic diagram after mold opening (sometimes also referred to as demolding) in step S30 of an embodiment of the present application. Refer to Figure 19 , after mold opening, a through hole 31 is reserved in the back encapsulation part 30, and the through hole 31 can be in a strip shape. Perform step S20 on the circuit board with the back encapsulation part 30 obtained. In the step S20, heat dissipation ribs are made in the through hole of the back encapsulation part, so as to obtain a composite substrate as shown in Figure 15 .

[0124] Furthermore, in one embodiment, after the steps S20 and S30, the following steps S31 and S32 can also be performed.

[0125] Step S31, a secondary encapsulation part is made on the bottom surface of the back encapsulation part through a molding process. The secondary encapsulation part has a secondary through hole, and the secondary through hole exposes the bottom surface of the heat dissipation rib and the contiguous area of the bottom surface of the back encapsulation part around the heat dissipation rib. Figure 20 The figure shows a schematic diagram of the formed molding cavity after mold closing in step S31 of an embodiment of the present application. Refer to Figure 20 It can be seen that in this embodiment, the upper mold 91 can have a plurality of downward protruding structures 93. These protruding structures 93 hold against the upper surface of the composite substrate (referring to the composite substrate obtained after completing steps S20 and S30 (this composite substrate can be composed of a circuit board 10, a heat dissipation rib 20, and a back encapsulation part 30). In this embodiment, this composite substrate is actually still a semi-finished product)), and it should be noted that since the composite substrate is inverted in Figure 20 , its upper surface is actually the back surface. A molding cavity surrounding the protruding structure 93 can be formed between the upper mold 91 and the composite substrate. Figure 21 The figure shows a schematic diagram after molding in step S31 of an embodiment of the present application. Refer to Figure 21 It can be seen that by injecting a liquid molding material into the molding cavity and curing it, a secondary molding part with the reserved secondary through hole (shown in Figure 22 ) can be obtained, that is, the secondary encapsulation part 32. Further, Figure 22 The figure shows a schematic diagram after mold opening (sometimes also referred to as demolding) in step S31 of an embodiment of the present application. Refer to Figure 22 , after mold opening, a composite substrate with a secondary encapsulation part 32 can be obtained. The secondary encapsulation part 32 has a secondary through hole 33, and the secondary through hole 33 exposes the bottom surface of the heat dissipation rib 20 (with the bottom surface facing upward in Figure 22 ) and the contiguous area 34 of the bottom surface of the back encapsulation part around the heat dissipation rib 20.

[0126] Step S32, make a heat dissipation extension part in the secondary through hole to obtain a composite substrate with a heat dissipation extension part. Figure 23Shows a composite substrate with a heat dissipation extension in an embodiment of the present application. This composite substrate can be used to fabricate a photosensitive component as shown in Figure 8 . Referring to Figure 8 and Figure 23 , the top surface of the heat dissipation extension 22 is connected to the bottom surface of the heat dissipation rib 20, and the bottom surface of the heat dissipation extension 22 is flush with the bottom surface of the secondary encapsulation portion 32 (note that in Figure 23 , the bottom surface is placed upward). Among them, the heat dissipation extension 22 is fabricated by means of implanting a metal layer or pouring a thermally conductive colloidal substance and hardening it, or by bonding or welding a preformed component.

[0127] Further, in an embodiment of the present application, step S40 may further include: mounting at least a part of the electronic components on the second surface of the circuit board. The step of mounting the electronic components on the second surface may be performed prior to step S30. In this way, in step S30, the back encapsulation layer can cover the electronic components mounted on the second surface (or fill the gaps around the electronic components) to achieve the encapsulation effect.

[0128] Further, in an embodiment, step S40 may further include: fabricating a front molding portion on the first surface of the circuit board. The front molding portion is fabricated on the first surface by a molding process and surrounds the photosensitive chip, and the top surface of the front molding portion is suitable for mounting a lens assembly.

[0129] Further, in an embodiment, in step S30, the back encapsulation portion is a back molding portion, and the front molding portion and the back molding portion can be simultaneously formed on the circuit board by the same molding process. This will help improve production efficiency and save costs.

[0130] Further, in an embodiment, in step S10, the prepared circuit board may be a circuit board panel formed by connecting a plurality of single circuit boards together. Figure 16A Shows a circuit board panel containing a connector portion. This circuit board panel may be a rigid-flexible board. Figure 16BA panel of circuit boards without a connector part is shown. The panel of circuit boards can be a PCB board, or a rigid board for short. Further, in this embodiment, in step S20, the heat dissipation ribs are made on the second surface (i.e., the back surface) of the panel of circuit boards. That is, the heat dissipation ribs corresponding to multiple individual circuit boards are made at one time. In step S30, the back encapsulation parts corresponding to multiple individual circuit boards can be made by one-time molding, and the back encapsulation parts can integrally cover the second surface of the panel of circuit boards. In step S40, photosensitive chips can be respectively pasted (or otherwise installed) on the first surface corresponding to multiple individual circuit boards, thereby obtaining a panel of photosensitive components. Further, the method for manufacturing a photosensitive component in this embodiment further includes step S50: cutting the panel of photosensitive components to obtain separated individual photosensitive components.

[0131] Based on the method for manufacturing a photosensitive component in the above embodiment, the obtained photosensitive component can be further assembled with a lens component to obtain a complete imaging module. Here, the lens component can be a lens component with a motor or a lens component without a motor. The assembled imaging module can be an auto-focus imaging module or a fixed-focus imaging module.

[0132] Further, Figure 25 A cross-sectional schematic diagram of an imaging module in an embodiment of the present application is shown. Refer to Figure 25 , this imaging module includes a lens component 3000 and a photosensitive component 2000. In this embodiment, on the basis of the photosensitive component in the Figure 1 embodiment, a lens holder 2001 and a color filter 2002 mounted on the lens holder 2001 are added. The lens component 3000 can have a motor 3001, and the bottom surface of the motor is mounted on the top surface of the lens holder.

[0133] Further, Figure 26 A cross-sectional schematic diagram of an imaging module in another embodiment of the present application is shown. The difference between this embodiment and the Figure 25 embodiment is that an electronic component 50 is mounted on the back surface of the circuit board 10, and the electronic component 50 is covered and wrapped by a back molding part 30.

[0134] Further, Figure 27 A cross-sectional schematic diagram of an imaging module in yet another embodiment of the present application is shown. The difference between this embodiment and the Figure 25 embodiment is that the composite substrate of the photosensitive component 2000 is increased with a heat dissipation extension part 22.

[0135] Further, Figure 28 A cross-sectional schematic diagram of an imaging module in still another embodiment of the present application is shown. The difference between this embodiment and the Figure 25The embodiment is different in that the back molding part is cancelled in the composite substrate of the photosensitive component.

[0136] Further, Figure 29 FIG. shows a cross-sectional schematic diagram of an imaging module in yet another embodiment of the present application. This embodiment is different from Figure 28 the embodiment in that a front molding part 2003 is fabricated on the upper surface of the circuit board 10 of the photosensitive component 2000. The bottom surface of the motor can be mounted on the top surface of the front molding part 2003. The lens holder 2001 (corresponding to the lens bracket in the previous embodiments) is only used to mount the color filter 2002, and the lens holder 2001 is located inside the front molding part 2003 and outside the electronic component 50.

[0137] Further, Figure 30 FIG. shows a cross-sectional schematic diagram of an imaging module in yet another embodiment of the present application. This embodiment is different from Figure 28 the embodiment in that a front molding part 2003 is fabricated on the upper surface of the circuit board 10 of the photosensitive component 2000. The lens bracket 2001 is mounted on the top surface of the front molding part 2003, the color filter 2002 is mounted on the lens bracket 2001, and the lens assembly 3000 (the bottom surface of the motor) is mounted on the top surface of the lens bracket 2001.

[0138] Further, Figure 31 FIG. shows a cross-sectional schematic diagram of an imaging module in yet another embodiment of the present application. This embodiment is different from Figure 30 the embodiment in that the front molding part 2003 covers the electronic component 50 and the metal wires and contacts the photosensitive chip 40. In this embodiment, the front molding part 2003 can cover the edge area of the photosensitive chip, and this edge area can be a non-photosensitive area.

[0139] Further, according to an embodiment of the present application, an electronic device is further provided. The electronic device has the imaging module of any one of the foregoing embodiments. The electronic device can be, for example, a smart phone, a tablet computer, etc.

[0140] Herein, the heat dissipation rib can be understood as: a reinforcing rib having a heat dissipation function.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A composite substrate for a camera module, characterized in that The composite substrate includes: A circuit board having a first surface and a second surface opposite to the first surface, wherein the first surface has a chip attachment area for attaching a photosensitive chip; Heat dissipation ribs provided on the second surface of the circuit board, at least a part of the heat dissipation ribs being located in an area overlapping with the chip attachment area. The heat dissipation ribs are a plurality of linearly arranged strip-shaped heat dissipation ribs arranged in parallel, and the direction of the heat dissipation ribs is parallel to the second surface; and A back molding part manufactured by a molding process on the second surface provided with the heat dissipation ribs, such that the back molding part covers the second surface and fills the gaps between the heat dissipation ribs, and the back molding part, the heat dissipation ribs and the circuit board are integrated; Wherein, the bottom surface of the back molding part is flush with the bottom surface of the heat dissipation ribs; or the back molding part covers the bottom surface of the heat dissipation ribs.

2. The composite substrate according to claim 1, wherein, The thickness of the heat dissipation ribs is not greater than 0.1 mm.

3. The composite substrate according to claim 2, wherein The thickness of the back molding part is not greater than 0.2 mm.

4. The composite substrate according to claim 1, wherein The heat dissipation ribs are directly manufactured on the second surface or attached to the second surface.

5. The composite substrate according to claim 1, wherein The heat dissipation ribs are metal heat dissipation ribs or heat dissipation ribs formed by hardening a thermally conductive colloidal substance.

6. The composite substrate according to claim 2, wherein The composite substrate further includes a secondary heat dissipation part. The top surface of the secondary heat dissipation part is connected to the bottom surface of the heat dissipation ribs. The bottom surface of the back molding part is flush with the bottom surface of the secondary heat dissipation part. The bottom surface of the secondary heat dissipation part is exposed outside the back molding part, and the area of the bottom surface of the secondary heat dissipation part is larger than the area of the bottom surface of the heat dissipation ribs.

7. The composite substrate according to claim 1, wherein The heat dissipation ribs are attached to the second surface by bonding or welding.

8. The composite substrate according to claim 1, wherein The root of the heat dissipation ribs extends into the interior of the circuit board.

9. The composite substrate according to claim 1, wherein The circuit board is a multilayer board, and the multilayer board includes a plurality of conductive layers and a plurality of insulating layers arranged at intervals, and the conductive layers and the insulating layers are combined together by a lamination process.

10. A photosensitive component, characterized in that, Comprising: The composite substrate according to any one of claims 1-9; A photosensitive chip, the bottom surface of which is attached to the chip attachment area of the composite substrate; And A metal wire that electrically connects the photosensitive chip and the circuit board through a wire bonding process.

11. The photosensitive component according to claim 10, wherein, The photosensitive component further includes a front molding part, which is manufactured by a molding process on the first surface and surrounds the photosensitive chip, and the top surface of the front molding part is adapted to mount a lens assembly; wherein there is a gap between the front molding part and the photosensitive chip, or the front molding part extends towards the photosensitive chip and contacts the photosensitive chip.

12. The photosensitive component according to claim 10, wherein The photosensitive component further includes a lens holder, which is mounted on the first surface and surrounds the photosensitive chip, and the top surface of the lens holder is adapted to mount a lens assembly; wherein the lens holder is mounted on the first surface after being formed.

13. The photosensitive component according to claim 11, wherein The photosensitive component further includes a lens holder, which is mounted on the front molding part, and the top surface of the lens holder is adapted to mount a lens assembly; wherein the lens holder is mounted on the front molding part after being formed.

14. An imaging module, characterized in that, Comprising: The photosensitive component according to any one of claims 10-13; And The lens assembly is mounted on the photosensitive component.

15. A method for manufacturing a composite substrate, characterized in that, Comprising: Step 1) Prepare a circuit board, the circuit board having a first surface and a second surface opposite to the first surface, wherein the first surface has a chip attachment area for attaching a photosensitive chip, and the thickness of the circuit board is not greater than 0.3 mm; Step 2) Provide heat dissipation ribs on the second surface, at least a part of the heat dissipation ribs being located in an area overlapping with the chip attachment area, the heat dissipation ribs being a plurality of linearly arranged strip-shaped heat dissipation ribs arranged in parallel, and the direction of the heat dissipation ribs being parallel to the second surface; And Step 3) Produce a back molding part on the second surface provided with the heat dissipation ribs by a molding process, the back molding part covering the second surface and filling the gaps between the heat dissipation ribs, such that the back molding part, the heat dissipation ribs and the circuit board are integrated; and, the bottom surface of the back molding part is flush with the bottom surface of the heat dissipation ribs, or the back molding part covers the bottom surface of the heat dissipation ribs.

16. The method for manufacturing a composite substrate according to claim 15, wherein, In step 2), the heat dissipation ribs are attached by welding or bonding, and the thickness of the heat dissipation ribs is not greater than 0.1 mm.

17. The method for manufacturing a composite substrate according to claim 15, wherein In step 1), a seed layer is provided in the circuit board, and in step 2), a metal layer is plated on the seed layer such that the metal layer grows and extends beyond the second surface, thereby forming the heat dissipation ribs; the thickness of the metal layer extending beyond the second surface is not greater than 0.1 mm.

18. The method for manufacturing a composite substrate according to claim 15, wherein, In step 2), a thermally conductive colloidal substance is coated on the second surface, and then the thermally conductive colloidal substance is hardened, thereby forming the heat dissipation ribs, and the thickness of the heat dissipation ribs is not greater than 0.1 mm.

19. A method for manufacturing a photosensitive component, characterized in that, Comprising: Fabricate a composite substrate according to the method for fabricating a composite substrate according to any one of claims 15-18; The method for fabricating the photosensitive component further comprises: Step 4) Attach a photosensitive chip to the first surface of the circuit board, install electronic components, and electrically connect the circuit board to the photosensitive chip by a wire bonding process.

20. The method for manufacturing a photosensitive component according to claim 19, wherein, Step 4) further comprises: producing a front molding part on the first surface, the front molding part being produced on the first surface by a molding process and surrounding the photosensitive chip, and the top surface of the front molding part being adapted to mount a lens assembly.

21. The method for manufacturing a photosensitive component according to claim 20, wherein In step 3) and step 4), the front molding part and the back molding part are simultaneously formed on the circuit board by the same molding process.

22. The method for manufacturing a photosensitive component according to claim 19, wherein, Step 4) further comprises: installing a pre-formed lens holder on the first surface, the lens holder surrounding the photosensitive chip.

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