CN114390782A

CN114390782A - Composite circuit board, preparation method thereof and camera module

Info

Publication number: CN114390782A
Application number: CN202011111516.5A
Authority: CN
Inventors: 杨成艺; 张鹏; 黎耀才; 李彪; 侯宁; 宋强
Original assignee: Avary Holding Shenzhen Co Ltd; Qing Ding Precision Electronics Huaian Co Ltd
Current assignee: Avary Holding Shenzhen Co Ltd; Qing Ding Precision Electronics Huaian Co Ltd
Priority date: 2020-10-16
Filing date: 2020-10-16
Publication date: 2022-04-22

Abstract

The application provides a composite circuit board, a preparation method thereof and a camera module. The preparation method comprises the following steps: a circuit board is provided with a through slot. Providing a heat conduction reinforcing sheet, which comprises a reinforcing sheet and a copper plating layer, wherein a through hole is formed in the reinforcing sheet, and the copper plating layer is arranged on the surface opposite to the reinforcing sheet and filled in the through hole. And laminating the circuit board, the adhesive layer and the heat conduction reinforcing sheet to enable the heat conduction reinforcing sheet to correspond to the slot and the area of the circuit board surrounding the slot. And pressing, so that the adhesive layer is connected with the circuit board and the heat conduction reinforcing sheet, thereby obtaining the composite circuit board. This application can effectively reduce composite circuit board thickness, and the heat conduction reinforcement piece can compromise high heat conduction and high rigidity, makes composite circuit board can effectively dispel the heat.

Description

Composite circuit board, preparation method thereof and camera module

Technical Field

The application relates to the field of circuit board preparation, in particular to a composite circuit board, a preparation method thereof and a camera module with the composite circuit board.

Background

The camera module generally includes a lens assembly, a base, a filter, a light sensing chip, and a circuit board. When the camera module works, the photosensitive chip can continuously generate heat, so that the heat is conducted to the circuit board for bearing the photosensitive chip.

However, if the circuit board fails to dissipate heat effectively, it is easy to deform and even damage the components on the circuit board, so that the photosensitive chip cannot work normally. Moreover, the circuit board needs to have certain rigidity, so that the photosensitive chip is prevented from being broken due to the deformation of the circuit board in the wire bonding process. However, the increase of the thickness of the circuit board is contrary to the trend of light, thin, small and small electronic products.

Disclosure of Invention

In order to solve at least one of the above disadvantages in the prior art, it is necessary to provide a composite circuit board and a method for manufacturing the same.

In addition, it is also necessary to provide a camera module having the composite circuit board.

The application provides a preparation method of a composite circuit board, which comprises the following steps: a circuit board is provided with a through slot. Providing a heat-conducting reinforcing sheet, which comprises a reinforcing sheet and a copper-plated layer, wherein the reinforcing sheet is provided with a through hole, and the copper-plated layer is arranged on the opposite surface of the reinforcing sheet and filled in the through hole. And laminating the circuit board, the adhesive layer and the heat conduction reinforcing sheet to enable the heat conduction reinforcing sheet to correspond to the slot and the area of the circuit board surrounding the slot. And pressing to enable the adhesive layer to be connected with the circuit board and the heat conduction reinforcing sheet, so that the composite circuit board is obtained.

In a possible implementation manner, the heat-conducting reinforcing sheet further comprises a plurality of heat-conducting pillars, the heat-conducting pillars are arranged on the surface of one of the copper-plated layers, and the heat-conducting pillars extend into the slots.

In one possible implementation manner, the heat-conducting reinforcing sheet further comprises a surface treatment layer, and the surface treatment layer is arranged on the surface of the other copper-plated layer.

In one possible implementation manner, the copper plating layer provided with the heat conduction column comprises a first mounting area and a second mounting area arranged around the first mounting area, the thickness of the first mounting area is greater than that of the second mounting area, so that the surface of the first mounting area is arranged in a protruding manner compared with the surface of the second mounting area, and the heat conduction column is arranged on the surface of the first mounting area in the protruding manner; the adhesive layer connects the circuit board and the second mounting region such that a portion of the first mounting region which is disposed to protrude extends into the slot.

The present application further provides a composite circuit board, including: the circuit board is provided with a through slot; the heat conduction reinforcing sheet comprises a reinforcing sheet and a copper plating layer, wherein a through hole is formed in the reinforcing sheet, and the copper plating layer is arranged on the opposite surface of the reinforcing sheet and filled in the through hole; and the adhesive layer is arranged between the circuit board and the heat conduction reinforcing plate, the adhesive layer is connected with the circuit board and the heat conduction reinforcing sheet, and the heat conduction reinforcing sheet corresponds to the slot and the area of the circuit board surrounding the slot.

In a possible implementation manner, the copper plating layer provided with the heat conduction column comprises a first mounting area and a second mounting area arranged around the first mounting area, the thickness of the first mounting area is greater than that of the second mounting area, so that the surface of the first mounting area is arranged in a protruding manner compared with the surface of the second mounting area, and the heat conduction column is arranged on the surface of the first mounting area in a protruding manner. The adhesive layer connects the circuit board and the second mounting region such that a portion of the first mounting region which is disposed to protrude extends into the slot.

The application also provides a camera module, which comprises a photosensitive chip, a lens base, a lens and an optical filter, wherein the lens and the optical filter are arranged in the lens base. The camera module still includes composite circuit board, and composite circuit board includes: the circuit board is provided with a through slot; the heat conduction reinforcing sheet comprises a reinforcing sheet and a copper plating layer, wherein a through hole is formed in the reinforcing sheet, and the copper plating layer is arranged on the opposite surface of the reinforcing sheet and filled in the through hole; and the adhesive layer is arranged between the circuit board and the heat conduction reinforcing plate, the adhesive layer is connected with the circuit board and the heat conduction reinforcing sheet, and the heat conduction reinforcing sheet corresponds to the slot and the area surrounded by the circuit board. The light sensitive chip is accommodated in the slot and is arranged on the heat conduction reinforcing sheet, and the light filter is positioned between the lens and the light sensitive chip.

In a possible implementation manner, the heat-conducting reinforcing sheet further comprises a plurality of heat-conducting columns, the heat-conducting columns are arranged on the surface of one copper-plated layer, the heat-conducting columns extend into the groove, and heat-conducting materials are filled between the groove and the heat-conducting columns and between the heat-conducting columns and the photosensitive chip.

In one possible implementation manner, the circuit board comprises an outer circuit layer and a protective layer arranged on the outer circuit layer, a part of the outer circuit layer is exposed to the protective layer to form a welding pad, and the photosensitive chip is electrically connected to the welding pad through a lead.

Compared with the prior art, the photosensitive chip is arranged on the heat conduction reinforcing sheet, and the heat conduction reinforcing sheet comprises the reinforcing sheet and the second copper plating layer, so that the reinforcing sheet has higher hardness, the photosensitive chip can be effectively supported, the phenomenon that the thickness of a circuit board is increased due to the improvement of the rigidity of the circuit board in the prior art is avoided, and the thickness of a composite circuit board can be effectively reduced; furthermore, the heat that the sensitization chip produced can conduct to the heat conduction reinforcement piece to give off to the external world by the heat conduction reinforcement piece, because the material coefficient of heat conductivity on second copper plate layer is higher than the reinforcement piece, consequently can improve the heat conduction effect of heat conduction reinforcement piece (the heat conduction reinforcement piece can compromise high heat conduction and high rigidity promptly), and then make the effective heat dissipation of composite circuit board.

Drawings

Fig. 1 is a schematic cross-sectional view illustrating a first adhesive layer and a copper foil layer laminated on an inner-layer circuit substrate according to an embodiment of the present disclosure.

Fig. 2 is a schematic cross-sectional view of the copper foil layer shown in fig. 1 after an outer circuit layer is formed thereon and covered with a second passivation layer.

Fig. 3 is a schematic cross-sectional view of the structure shown in fig. 2 after forming a slot therein.

FIG. 4 is a cross-sectional view of a reinforcing sheet having a through-hole and a second copper plating layer formed thereon according to one embodiment of the present invention.

Fig. 5 is a cross-sectional view of the second copper plating layer shown in fig. 4 after planarization.

Fig. 6 is a schematic cross-sectional view of the heat-conducting reinforcing sheet obtained after surface treatment of the second copper plating layer shown in fig. 5.

Fig. 7 is a schematic cross-sectional view of a composite circuit board obtained by laminating and pressing the circuit board shown in fig. 3 and the heat-conducting reinforcing sheet shown in fig. 6 through a second adhesive layer.

Fig. 8 is a schematic cross-sectional view of the composite circuit board shown in fig. 7 after a photo sensor chip is mounted in the groove.

Fig. 9 is a schematic cross-sectional view of a camera module obtained by mounting a lens holder on the composite circuit board shown in fig. 8.

FIG. 10 is a cross-sectional view of a reinforcing patch in accordance with another embodiment of the present application.

Fig. 11 is a schematic cross-sectional view of the reinforcing sheet shown in fig. 10 after processing.

FIG. 12 is a schematic cross-sectional view of a thermally conductive reinforcing sheet obtained by surface treating the reinforcing sheet shown in FIG. 11.

Fig. 13 is a schematic cross-sectional view of a composite circuit board obtained by laminating and laminating the circuit board shown in fig. 3 and the heat-conducting reinforcing sheet shown in fig. 12.

Fig. 14 is a schematic cross-sectional view of the composite circuit board shown in fig. 13 after a photo sensor chip is mounted in the groove.

Fig. 15 is a schematic cross-sectional view of the camera module obtained by filling the thermal conductive material between the trench, the conductive pillar and the photo sensor chip shown in fig. 14 and mounting the lens holder on the composite circuit board.

Description of the main elements

Heat-conducting post 44 of inner layer circuit substrate 10

Base layer 11 thermally conductive material 45

Inner circuit layer 12 photosensitive chip 50

Insulation 13 wire 51

First protective layer 14 tie layer 52

First adhesive layer 20 lens holder 60

Copper foil layer 21 lens 61

First copper plating layer 22 filter 62

Second adhesive layer 70 of outer circuit layer 23

Second protective layer 24

composite circuit boards

100, 200

Slot 25 pad 230

Circuit board 30

camera module

300, 400

Blind groove 33 through hole 410

First mounting region 421 of heat-conducting reinforcing

sheet

40, 40

Second mounting region 422 of reinforcing sheet 41

The second copper plating layer 42 has thicknesses T1, T2

Surface treatment layer 43

The following detailed description will further illustrate the present application in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

To further explain the technical means and effects of the present application for achieving the intended purpose, the following detailed description is given to the present application in conjunction with the accompanying drawings and preferred embodiments.

Referring to fig. 1 to 7, an embodiment of the present application provides a method for manufacturing a composite circuit board 100, the method including the following steps:

s11, referring to fig. 1, an inner layer circuit board 10 is provided, and the surface of the inner layer circuit board 10 is covered with the first adhesive layer 20 and the copper foil layer 21.

The first adhesive layer 20 may be made of common pure glue.

In one embodiment, the inner circuit substrate 10 includes a base layer 11, an inner circuit layer 12 disposed on a surface of the base layer 11, and an insulating layer 13 and a first protective layer 14 sequentially disposed on a surface of the inner circuit layer 12. As shown in the drawing, the inner layer circuit board 10 in the present embodiment is a flexible double-sided circuit board, that is, the inner circuit layers 12 are provided on both surfaces of the base layer 11 facing each other. In another embodiment, the number of the circuit layers in the inner circuit substrate 10 may be changed, for example, at least one intermediate circuit layer (not shown) may be formed on the surface of each inner circuit layer 12 by a layer-adding process.

The material of the base layer 11 is an insulating resin, and specifically, the material of the base layer 11 may be one of epoxy resin (epoxy resin), polypropylene (PP), BT resin, Polyphenylene Oxide (PPO), polypropylene (PP), Polyimide (PI), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN).

The material of the insulating layer 13 is an insulating resin, and specifically, the material of the insulating layer 13 may be one selected from resins such as epoxy resin, polypropylene, BT resin, polyphenylene ether, polypropylene, polyimide, polyethylene terephthalate, and polyethylene naphthalate. The material of the insulating layer 13 may be the same as or different from that of the base layer 11.

The first protective layer 14 may be a solder resist layer or a coverlay film (CVL). The first protective layer 14 serves to prevent oxidation or solder shorting of the inner wiring layer 12.

S12, referring to fig. 2, a first copper plating layer 22 is formed on the surface of the copper foil layer 21 by electroplating, the copper foil layer 21 and the first copper plating layer 22 are etched by exposure and development process to obtain an outer circuit layer 23, and then the outer circuit layer 23 is covered with a second passivation layer 24.

Wherein a partial region of one of the outer circuit layers 23 is exposed to the second passivation layer 24 to form two bonding pads 230. Each pad 230 is used for electrically connecting the photosensitive chip 50 (see fig. 8 and 9). The second protective layer 24 may be a solder resist layer or a coverlay film (CVL). The second protective layer 24 serves to prevent the outer wiring layer 23 from being oxidized or short-circuited by soldering.

S13, referring to fig. 3, at least one through slot 25 is opened in the second protective layer 24, the outer circuit layer 23, the first adhesive layer 20 and the inner circuit substrate 10, so as to obtain the circuit board 30.

Wherein the slot 25 can be formed by punching or laser drilling.

When the inner circuit substrate 10 is a flexible circuit substrate, the circuit board 30 finally formed is a rigid-flex board. Further, the circuit board 30 is provided with a blind groove 33 penetrating through the second protective layer 24, the outer circuit layer 23 and the first adhesive layer 20. The blind slot 33 is located at a distance from the slot 25. The blind groove 33 does not penetrate the inner circuit substrate 10, so that the first protective layer 14 is exposed to the blind groove 33. Thus, the portion of the inner circuit board 10 corresponding to the blind groove 33 constitutes a soft plate portion of the rigid-flex circuit board. In other embodiments, the circuit board 30 is not limited to a rigid-flex board, but may be a rigid board or a flexible board.

S14, please refer to fig. 4 to 6, a heat-conducting reinforcing plate 40 is provided, which includes a reinforcing plate 41 and a second copper-plated layer 42. The reinforcing sheet 41 has a plurality of through holes 410 formed therein. The second copper plating layer 42 is disposed on the opposite surface of the reinforcing sheet 41 and fills each through hole 410.

Wherein the width of the via 410 is 100-400 μm. The width of the through hole 410 is defined as the dimension of the through hole 410 along the extending direction of the circuit board 30. The distance between two adjacent through holes 410 is not less than 60 micrometers.

In one embodiment, the thermally conductive reinforcing sheet 40 further includes a surface treatment layer 43 disposed on the surface of the second copper plating layer 42. The surface treatment layer 43 may be formed by electroless gold plating, electroless nickel plating, or the like. The surface treatment layer 43 serves to prevent the second copper plating layer 42 from oxidizing.

In one embodiment, the total thickness of the thermally conductive stiffener 40 (i.e., the sum of the thicknesses of the stiffener 41, the second copper plating layer 42, and the surface treatment layer 43) is 50-400 microns. The thickness of the heat-conducting reinforcing sheet 40 is defined as the dimension of the heat-conducting reinforcing sheet 40 along the extending direction of the circuit board 30. The width of the heat-conducting reinforcing sheet 40 may be greater than the width of the slot 25.

The material of the reinforcing sheet 41 may be steel.

In one embodiment, the thermally conductive reinforcing sheet 40 may be prepared by:

as shown in fig. 4, a reinforcing sheet 41 is provided, and a plurality of through holes 410 are opened in the reinforcing sheet 41. Each through hole 410 penetrates the reinforcing sheet 41. Then, the surface of the reinforcing sheet 41 and the through-hole 410 are plated to form the second copper plated layer 42.

As shown in fig. 5, the second copper plating layer 42 on the surface of the reinforcing sheet 41 is planarized. In this embodiment, the second copper plating layer 42 may be planarized by grinding or mechanical milling.

As shown in fig. 6, a surface treatment is performed on the planarized second copper plating layer 42 to form a surface treatment layer 43, thereby obtaining a thermally conductive reinforcing sheet 40.

S15, please refer to fig. 7, the circuit board 30, the second adhesive layer 70 and the heat-conducting reinforcing sheet 40 are stacked. After lamination, the outer circuit layer 23 with the bonding pad 230 is located on the surface of the circuit board 30 away from the heat-conducting reinforcing sheet 40, and the heat-conducting reinforcing sheet 40 corresponds to the slot 25 and the area of the circuit board 30 surrounding the slot 25. And then, performing pressing to connect the second adhesive layer 70 with the circuit board 30 and the heat-conducting reinforcing sheet 40, so as to obtain the composite circuit board 100.

In this embodiment, after obtaining the composite circuit board 100, the manufacturing method further includes:

s16, referring to fig. 8, the photo chip 50 is placed in the slot 25 and mounted on the heat-conducting reinforcing sheet 40, and the photo chip 50 is electrically connected to the pad 230 through the wire 51.

In one embodiment, the photosensitive chip 50 is mounted on the thermally conductive reinforcing sheet 40 through the connection layer 52. The connecting layer 52 may be a solder layer or a conductive paste layer (e.g., solder paste).

S17, referring to fig. 9, a lens holder 60 is mounted on the second passivation layer 24 corresponding to the outer circuit layer 23 having the bonding pads 230, a lens 61 and a filter 62 opposite to the lens 61 are disposed in the lens holder 60, so that the filter 62 is located between the lens 61 and the photo chip 50, thereby obtaining the camera module 300.

Referring to fig. 7, the present application further provides a composite circuit board 100 manufactured by the above manufacturing method. The composite circuit board 100 includes a circuit board 30, a second adhesive layer 70 and a heat-conducting reinforcing sheet 40 stacked in sequence. The second adhesive layer 70 connects the circuit board 30 and the thermally conductive reinforcing sheet 40.

The circuit board 30 includes an inner circuit substrate 10, and the inner circuit substrate 10 includes a base layer 11, an inner circuit layer 12 disposed on a surface of the base layer 11, and an insulating layer 13 and a first protective layer 14 sequentially disposed on a surface of the inner circuit layer 12. The circuit board 30 further includes a first adhesive layer 20, an outer circuit layer 23, and a second protective layer 24 sequentially stacked on the inner circuit substrate 10. Wherein a partial region of one of the outer circuit layers 23 is exposed to the second passivation layer 24 to form two bonding pads 230. The circuit board 30 has a slot 25, and the slot 25 penetrates through the second protective layer 24, the outer circuit layer 23, the first adhesive layer 20 and the inner circuit board 10.

The thermally conductive stiffener 40 includes a stiffener 41 and a second copper plated layer 42. The reinforcing sheet 41 has a plurality of through holes 410 formed therein. The second copper plating layer 42 is disposed on the opposite surface of the reinforcing sheet 41 and fills each through hole 410. The thermally conductive reinforcing sheet 40 may further include a surface treatment layer 43 disposed on the surface of the second copper plating layer 42.

The outer circuit layer 23 with the bonding pads 230 is located on the surface of the circuit board 30 away from the heat-conducting reinforcing sheet 40, and the heat-conducting reinforcing sheet 40 corresponds to the slot 25 and the area of the circuit board 30 surrounding the slot 25.

Referring to fig. 9, the present application further provides a camera module 300 manufactured by the above manufacturing method. The camera module 300 includes the circuit board 100, the photosensitive chip 50 and the lens holder 60. The lens base 60 is provided with a lens 61 and a filter 62 opposite to the lens 61.

The photo chip 50 is accommodated in the slot 25 and mounted on the heat-conducting reinforcing sheet 40, and the photo chip 50 is electrically connected to the pad 230 through the wire 51. The filter 62 is located between the lens 61 and the photosensitive chip 50.

Compared with the prior art in which the photosensitive chip 50 is mounted on the circuit board 30, the photosensitive chip 50 in the present application is mounted on the heat-conducting reinforcing sheet 40. Because the heat-conducting reinforcing sheet 40 includes the reinforcing sheet 41 and the second copper-plated layer 42, the reinforcing sheet 41 has higher hardness, so that the photosensitive chip 50 can be effectively supported, and the increase of the thickness of the circuit board 30 due to the increase of the rigidity of the circuit board 30 in the prior art can be avoided. Therefore, the thickness of the composite circuit board 100 can be effectively reduced, so that the composite circuit board 100 is more suitable for light and thin electronic products. Furthermore, the heat generated by the photosensitive chip 50 can be conducted to the heat-conducting reinforcing sheet 40 and dissipated to the outside through the heat-conducting reinforcing sheet 40. Since the second copper plating layer 42 has a higher thermal conductivity than the reinforcing sheet 41, the thermal conductivity of the thermal-conductive reinforcing sheet 40 can be improved (i.e., the thermal-conductive reinforcing sheet 40 can have both high thermal conductivity and high rigidity), so that the composite circuit board 100 can dissipate heat effectively.

Another embodiment of the present application further provides a method for manufacturing the composite circuit board 200, wherein the steps of preparing the circuit board 30 in steps S21 to S23 are the same as those in steps S11 to S13, which are not repeated herein. Referring to fig. 10 to 15, after step S23, the method further includes the following steps:

s24, please refer to fig. 10 to 12, a thermally conductive stiffener 40' is provided, which includes a stiffener 41 and a second copper plating layer 42. The reinforcing sheet 41 has a plurality of through holes 410 formed therein. The second copper plating layer 42 is disposed on the opposite surface of the reinforcing sheet 41 and fills each through hole 410.

The difference from the heat-conducting reinforcing sheet 40 is that in the heat-conducting reinforcing sheet 40', a plurality of heat-conducting pillars 44 are further disposed on the surface of a second copper-plated layer 42, and the heat-conducting pillars 44 may be integrally formed by extending the second copper-plated layer 42 (i.e., the heat-conducting pillars 44 are also made of copper). The thermal pillars 44 may extend perpendicular to the surface of the second copper plating layer 42. In an embodiment, the second copper plating layer 42 includes a first mounting region 421 and a second mounting region 422 disposed around the first mounting region 421. The thickness T1 of the first mounting region 421 can be greater than the thickness T2 of the second mounting region 422, such that the surface of the first mounting region 421 is convexly disposed compared to the surface of the second mounting region 422. The heat conduction post 44 is disposed on a surface of the first mounting region 421.

In one embodiment, the first mounting region 421 protrudes to a height of 50-200 μm compared to the second mounting region 422.

In one embodiment, the thermally conductive stiffener 40' further includes a surface treatment 43. The surface treatment layer 43 is disposed on the surface of the second copper plating layer 42 away from the heat conduction post 44. The surface treatment layer 43 may be formed by electroless gold plating, electroless nickel plating, or the like. The surface treatment layer 43 serves to prevent the reinforcing sheet 41 from oxidizing.

In one embodiment, the thermally conductive reinforcing sheet 40' may be prepared by:

as shown in fig. 10, a reinforcing sheet 41 is provided, and a plurality of through holes 410 are opened in the reinforcing sheet 41. Each through hole 410 penetrates the reinforcing sheet. Then, the surface of the reinforcing sheet 41 and the through-hole 410 are plated to form the second copper plated layer 42.

As shown in fig. 11, the second copper plating layer 42 is subjected to Computer Numerical Control (CNC) machining, and after the machining, a second copper plating layer 42 forms first and second mounting

areas

421 and 422 having different thicknesses, and a heat conductive pillar 44 formed by extending a surface of the first mounting area 421.

As shown in fig. 12, a surface treatment is performed on the planarized second copper plating layer 42 to form a surface treatment layer 43, thereby obtaining a thermally conductive reinforcing sheet 40'.

S25, please refer to fig. 13, the circuit board 30, the second adhesive layer 70 and the heat-conducting reinforcing sheet 40' are laminated. After lamination, the outer circuit layer 23 with the bonding pads 230 is located on the surface of the circuit board 30 away from the heat-conducting reinforcing sheet 40 ', and the surface treatment layer 43 is located on the surface of the heat-conducting reinforcing sheet 40' away from the circuit board 30. The heat-conductive reinforcing sheet 40' corresponds to the slot 25 and the area of the circuit board 30 surrounding the slot 25, and the heat-conductive column 44 extends into the slot 25. And then, performing pressing to connect the second adhesive layer 70 with the circuit board 30 and the heat-conducting reinforcing sheet 40', thereby obtaining the composite circuit board 200.

More specifically, when the second copper plated layer 42 includes the first mounting area 421 and the second mounting area 422, which are different in thickness, the second adhesive layer 70 connects the circuit board 30 and the second mounting area 422 such that the protrudingly disposed portion of the first mounting area 421 also protrudes into the slot 25.

In this embodiment, after obtaining the composite circuit board 200, the manufacturing method further includes:

s26, referring to fig. 14, the photo chip 50 is placed in the slot 25 and mounted on the first mounting region 421 of the heat-conducting reinforcing sheet 40', and the photo chip 50 is electrically connected to the bonding pad 230 through the wire 51.

Since the thickness T1 of the first mounting region 421 is larger, the first mounting region 421 has higher thermal conductivity than the second mounting region 422, which is beneficial to quickly dissipate the heat conducted by the photosensitive chip 50 to the outside.

S27, referring to fig. 15, the thermal conductive material 45 is filled between the trench 25 and the thermal conductive pillar 44 and between the photo-sensing chip 50 and the thermal conductive pillar 44. Wherein the thermally conductive material 45 may also cover at least a portion of the conductive line 51.

In one embodiment, the gap between the trench 25 and the heat-conducting pillar 44 is 100 and 200 microns. The width of the thermal conductive pillar 44 is 100-500 microns. The width of the heat-conducting pillar 44 is defined as the dimension of the heat-conducting pillar 44 along the extending direction of the circuit board 30. The thermally conductive material 45 may be thermally conductive silicone.

S28, mounting a lens holder 60 on the second passivation layer 24 corresponding to the outer circuit layer 23 having the bonding pads 230, wherein the lens holder 60 is provided with a lens 61 and a filter 62 opposite to the lens 61, so that the filter 62 is located between the lens 61 and the photosensitive chip 50, thereby obtaining the camera module 400.

Referring to fig. 13, the present application further provides a composite circuit board 200 manufactured by the above manufacturing method. The composite circuit board 100 includes a circuit board 30, a second adhesive layer 70, and a heat-conductive reinforcing sheet 40 ', which are sequentially stacked, and the heat-conductive reinforcing sheet 40' has a different structure from the heat-conductive reinforcing sheet 40. The second adhesive layer 70 connects the circuit board 30 and the thermally conductive reinforcing sheet 40'.

The thermally conductive stiffener 40' includes a stiffener 41 and a second copper plating layer 42. The reinforcing sheet 41 has a plurality of through holes 410 formed therein. The second copper plating layer 42 is disposed on the opposite surface of the reinforcing sheet 41 and fills each through hole 410. The surface of one of the second copper plating layers 42 is further provided with a plurality of heat conduction pillars 44, and the heat conduction pillars 44 may be integrally formed by extending the second copper plating layer 42. In an embodiment, the second copper plating layer 42 includes a first mounting region 421 and a second mounting region 422 disposed around the first mounting region 421. The thickness T1 of the first mounting region 421 can be greater than the thickness T2 of the second mounting region 422, such that the surface of the first mounting region 421 is convexly disposed compared to the surface of the second mounting region 422. The heat conduction post 44 is disposed on a surface of the first mounting region 421. The heat-conducting reinforcing sheet 40 may further include a surface treatment layer 43, and the surface treatment layer 43 is disposed on the surface of the second copper plating layer 42 away from the heat-conducting pillar 44.

The outer circuit layer 23 with the bonding pads 230 is located on the surface of the circuit board 30 away from the heat-conducting reinforcing sheet 40 ', the surface treatment layer 43 is located on the surface of the heat-conducting reinforcing sheet 40' away from the circuit board 30, and the heat-conducting reinforcing sheet 40 corresponds to the slot 25 and the area of the circuit board 30 surrounding the slot 25. The heat-conducting post 44 extends into the slot 25.

Referring to fig. 14, the present application further provides a camera module 300 manufactured by the above manufacturing method. The camera module 300 includes the circuit board 200, the photosensitive chip 50 and the lens holder 60. The lens base 60 is provided with a lens 61 and a filter 62 opposite to the lens 61.

The photo chip 50 is accommodated in the slot 25 and mounted on the heat-conducting reinforcing sheet 40, and the photo chip 50 is electrically connected to the pad 230 through the wire 51. The filter 62 is located between the lens 61 and the photosensitive chip 50. A heat conductive material 45 is filled between the groove 25 and the heat conductive pillar 44 and between the photosensitive chip 50 and the heat conductive pillar 44. Wherein the thermally conductive material 45 may also cover at least a portion of the conductive line 51.

In the camera module 400 of this embodiment, the heat generated by the photosensitive chip 50 can be conducted to the heat-conducting pillar 44 and the ground layer (i.e., the inner circuit layer 12) through the heat-conducting material 45, so that the heat-conducting effect of the heat-conducting reinforcing sheet 40' can be improved.

It is understood that various other changes and modifications can be made by those skilled in the art based on the technical idea of the present application, and all such changes and modifications should fall within the protective scope of the claims of the present application.

Claims

1. A method for manufacturing a composite circuit board, comprising the steps of:

providing a circuit board, and arranging a through slot;

providing a heat conduction reinforcing sheet, wherein the heat conduction reinforcing sheet comprises a reinforcing sheet and a copper plating layer, a through hole is formed in the reinforcing sheet, and the copper plating layer is arranged on the opposite surface of the reinforcing sheet and filled in the through hole;

laminating the circuit board, the adhesive layer and the heat-conducting reinforcing sheet to enable the heat-conducting reinforcing sheet to correspond to the slot and the area of the circuit board surrounding the slot;

and pressing, so that the adhesive layer is connected with the circuit board and the heat conduction reinforcing sheet, thereby obtaining the composite circuit board.

2. The method of claim 1, wherein the thermally conductive stiffener further comprises a plurality of thermally conductive posts disposed on a surface of one of the copper layers, the thermally conductive posts extending into the slots.

3. The method of manufacturing a composite circuit board according to claim 2, wherein the thermally conductive reinforcing sheet further comprises a surface treatment layer, and the surface treatment layer is disposed on a surface of the other copper plating layer.

4. The method of producing a composite circuit board according to claim 2, wherein the copper plating layer provided with the heat-conducting post includes a first mounting area and a second mounting area provided around the first mounting area, the first mounting area having a thickness larger than that of the second mounting area such that a surface of the first mounting area is provided to protrude than a surface of the second mounting area, the heat-conducting post being provided on the surface of the first mounting area provided to protrude;

the adhesive layer connects the circuit board and the second mounting region such that a portion of the first mounting region that is disposed to protrude extends into the slot.

5. A composite circuit board, comprising:

the circuit board is provided with a through slot;

the heat conduction reinforcing sheet comprises a reinforcing sheet and a copper plating layer, wherein a through hole is formed in the reinforcing sheet, and the copper plating layer is arranged on the opposite surface of the reinforcing sheet and filled in the through hole;

the adhesive layer is arranged between the circuit board and the heat conduction reinforcing plate and is connected with the circuit board and the heat conduction reinforcing sheet, and the heat conduction reinforcing sheet corresponds to the slot and the area of the circuit board surrounding the slot.

6. The composite circuit board of claim 5, wherein the thermally conductive stiffener further comprises a plurality of thermally conductive posts disposed on a surface of one of the copper layers, the thermally conductive posts extending into the slots.

7. The composite circuit board of claim 6, wherein the thermally conductive stiffener further comprises a surface treatment layer disposed on a surface of the other copper plating layer.

8. The composite circuit board of claim 6, wherein the copper plating layer provided with the heat-conducting pillars includes a first mounting area and a second mounting area provided around the first mounting area, the first mounting area having a thickness greater than that of the second mounting area such that a surface of the first mounting area is provided to protrude than a surface of the second mounting area, the heat-conducting pillars being provided on the surface of the first mounting area provided to protrude;

9. The utility model provides a camera module, includes sensitization chip, microscope base and set up in lens and light filter in the microscope base, its characterized in that, camera module still includes composite circuit board, composite circuit board includes:

the circuit board is provided with a through slot;

the heat conduction reinforcing sheet comprises a reinforcing sheet and a copper plating layer, wherein a through hole is formed in the reinforcing sheet, and the copper plating layer is arranged on the opposite surface of the reinforcing sheet and filled in the through hole; and

the adhesive layer is arranged between the circuit board and the heat conduction reinforcing plate and is connected with the circuit board and the heat conduction reinforcing sheet, and the heat conduction reinforcing sheet corresponds to the open groove and the area of the circuit board surrounding the open groove;

the light sensing chip is accommodated in the groove and is arranged on the heat conduction reinforcing sheet, and the light filter is positioned between the light sensing chip and the lens.

10. The camera module of claim 9, wherein the thermally conductive stiffener further comprises a plurality of thermally conductive pillars disposed on a surface of one of the copper layers, the thermally conductive pillars extending into the slot, and thermally conductive material is filled between the slot and the thermally conductive pillars and between the thermally conductive pillars and the photo-sensing chip.

11. The camera module of claim 10, wherein the copper plating on which the thermal pillars are disposed includes a first mounting area and a second mounting area disposed around the first mounting area, the first mounting area having a thickness greater than a thickness of the second mounting area such that a surface of the first mounting area is disposed to protrude than a surface of the second mounting area, the thermal pillars being disposed on a surface of the first mounting area to protrude;

12. The camera module as claimed in claim 9, wherein the circuit board includes an outer circuit layer and a protection layer disposed on the outer circuit layer, a portion of the outer circuit layer is exposed to the protection layer to form a pad, and the photo sensor chip is electrically connected to the pad through a wire.