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

Abstract

The present application provides a composite circuit board, a preparation method thereof, and a camera module. The preparation method includes the steps of: providing a circuit board with a penetrating slot. A thermally conductive reinforcing sheet is provided, which includes a reinforcing sheet and a copper-plated layer, the reinforcing sheet is provided with a through hole, and the copper-plated layer is disposed on the opposite surface of the reinforcing sheet and filled in the through-hole. The circuit board, the adhesive layer and the thermally conductive reinforcing sheet are laminated so that the thermally conductive reinforcing sheet corresponds to the slot and the area of the circuit board surrounding the slot. Pressing, so that the adhesive layer connects the circuit board and the thermally conductive reinforcing sheet, so as to obtain a composite circuit board. The present application can effectively reduce the thickness of the composite circuit board, and the thermally conductive reinforcing sheet can take into account both high thermal conductivity and high rigidity, so that the composite circuit board can effectively dissipate heat.

Description

Composite circuit board and preparation method thereof, and camera module

technical field

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

Background technique

Camera modules usually include lens components, bases, filters, photosensitive chips, circuit boards and other components. When the camera module is working, the photosensitive chip will continuously generate heat, so that the heat is conducted to the circuit board used to carry the photosensitive chip.

However, if the circuit board fails to dissipate heat effectively, it is easy to cause deformation, and even damage the components on the circuit board, resulting in the failure of the photosensitive chip to work normally. Furthermore, the circuit board needs to have a certain rigidity to prevent the photosensitive chip from breaking due to the deformation of the circuit board during the wire bonding process. This requires the circuit board to have a certain thickness. However, increasing the thickness of the circuit board runs counter to the development trend of electronic products toward light, thin, and short.

SUMMARY OF THE INVENTION

In order to solve at least one of the above deficiencies in the prior art, it is necessary to provide a composite circuit board and a preparation method thereof.

In addition, it is also necessary to provide a camera module with the above-mentioned composite circuit board.

The present application provides a method for preparing a composite circuit board, comprising the steps of: providing a circuit board with a penetrating slot. A thermally conductive reinforcing sheet is provided, which includes a reinforcing sheet and a copper-plated layer, 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. The circuit board, the adhesive layer and the thermally conductive reinforcing sheet are laminated so that the thermally conductive reinforcing sheet corresponds to the slot and the area of the circuit board surrounding the slot. And, by pressing, the adhesive layer connects the circuit board and the thermally conductive reinforcing sheet, thereby obtaining a composite circuit board.

In a possible implementation manner, the thermally conductive reinforcing sheet further includes a plurality of thermally conductive pillars, the thermally conductive pillars are disposed on the surface of one of the copper-plated layers, and the thermally conductive pillars extend into the slots.

In a possible implementation manner, the thermally conductive reinforcing sheet further includes a surface treatment layer, and the surface treatment layer is disposed on the surface of another copper plating layer.

In a possible implementation manner, the copper plated layer provided with the thermally conductive post includes a first mounting area and a second mounting area arranged around the first mounting area, and 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 protruded from the surface of the second mounting area, and the thermally conductive post is arranged on the protruding surface of the first mounting area; the adhesive layer connects the circuit board and the second mounting area, so that the protruding part is first A mounting area extends into the slot.

The present application also provides a composite circuit board, comprising: a circuit board with a penetrating slot; a thermally conductive reinforcing sheet, including a reinforcing sheet and a copper-plated layer, the reinforcing sheet is provided with a through hole, and the copper-plated layer is disposed on the The opposite surface of the reinforcing sheet is filled in the through hole; and the adhesive layer is arranged between the circuit board and the thermally conductive reinforcing plate, and the adhesive layer connects the circuit board and the thermally conductive reinforcing sheet, and the thermally conductive reinforcing sheet and the slot and The circuit board corresponds to the area around the slot.

In a possible implementation manner, the thermally conductive reinforcing sheet further includes a plurality of thermally conductive pillars, the thermally conductive pillars are disposed on the surface of one of the copper-plated layers, and the thermally conductive pillars extend into the slots.

In a possible implementation manner, the thermally conductive reinforcing sheet further includes a surface treatment layer, and the surface treatment layer is disposed on the surface of another copper plating layer.

In a possible implementation manner, the copper plated layer provided with the thermally conductive post includes a first mounting area and a second mounting area arranged around the first mounting area, and the thickness of the first mounting area is greater than that of the second mounting area, so that The surface of the first installation area is protruded from the surface of the second installation area, and the heat conduction column is disposed on the protruded surface of the first installation area. The adhesive layer connects the circuit board and the second mounting area, so that the protruding part of the first mounting area extends into the slot.

The present application also provides a camera module, which includes a photosensitive chip, a lens holder, and lenses and filters disposed in the lens holder. The camera module also includes a composite circuit board, and the composite circuit board includes: a circuit board with a through slot; a thermally conductive reinforcing sheet, including a reinforcing sheet and a copper-plated layer, the reinforcing sheet is provided with a through hole, and the copper-plated layer is provided It 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 thermally conductive reinforcing plate, and the adhesive layer connects the circuit board and the thermally conductive reinforcing sheet, and the thermally conductive reinforcing sheet is connected with the opening. The slots correspond to the areas surrounding the circuit board. Wherein, the photosensitive chip is accommodated in the slot and mounted on the heat conduction reinforcing sheet, and the optical filter is located between the lens and the photosensitive chip.

In a possible implementation manner, the thermally conductive reinforcing sheet further includes a plurality of thermally conductive pillars, the thermally conductive pillars are disposed on the surface of one of the copper-plated layers, the thermally conductive pillars extend into the slots, between the slots and the thermally conductive pillars and between the thermally conductive pillars A thermally conductive material is filled between it and the photosensitive chip.

In a possible implementation manner, the copper plated layer provided with the thermally conductive post includes a first mounting area and a second mounting area arranged around the first mounting area, and the thickness of the first mounting area is greater than that of the second mounting area, so that The surface of the first installation area is protruded from the surface of the second installation area, and the heat conduction column is disposed on the protruded surface of the first installation area. The adhesive layer connects the circuit board and the second mounting area, so that the protruding part of the first mounting area extends into the slot.

In a possible implementation manner, the circuit board includes an outer circuit layer and a protective layer disposed on the outer circuit layer, a part of the outer circuit layer is exposed to the protective layer to form a bonding pad, and the photosensitive chip is electrically connected to the bonding pad through wires.

Compared with the prior art, the photosensitive chip in the present application is mounted on a thermally conductive reinforcing sheet. Since the thermally conductive reinforcing sheet includes a reinforcing sheet and a second copper-plated layer, the reinforcing sheet has higher hardness, so it can effectively support the photosensitive material. The chip can avoid the increase in the thickness of the circuit board due to the improvement of the rigidity of the circuit board in the prior art, so that the thickness of the composite circuit board can be effectively reduced; in addition, the heat generated by the photosensitive chip can be conducted to the thermally conductive reinforcing sheet and dissipated by the thermally conductive reinforcing sheet. To the outside world, since the thermal conductivity of the second copper-plated layer is higher than that of the reinforcing sheet, the thermal conductivity of the thermally conductive reinforcing sheet can be improved (that is, the thermally conductive reinforcing sheet can take both high thermal conductivity and high rigidity into account), thereby making the composite circuit board effective. heat dissipation.

Description of drawings

1 is a schematic cross-sectional view of a first adhesive layer and a copper foil layer on an inner-layer circuit substrate in an embodiment of the present application.

FIG. 2 is a schematic cross-sectional view after preparing an outer circuit layer on the copper foil layer described in FIG. 1 and covering the second protective layer.

FIG. 3 is a schematic cross-sectional view of the structure shown in FIG. 2 after opening a slot.

FIG. 4 is a schematic cross-sectional view of opening a through hole in the reinforcing sheet and electroplating a second copper plating layer according to an embodiment of the present application.

FIG. 5 is a schematic cross-sectional view of the second copper plating layer shown in FIG. 4 after leveling.

FIG. 6 is a schematic cross-sectional view of the thermally conductive reinforcing sheet obtained after the surface treatment is performed on the second copper plating layer described in FIG. 5 .

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 thermally conductive reinforcing sheet shown in FIG. 6 through a second adhesive layer.

FIG. 8 is a schematic cross-sectional view after installing a photosensitive chip in the slot of the composite circuit board shown in FIG. 7 .

FIG. 9 is a schematic cross-sectional view of the camera module obtained after the lens holder is mounted on the composite circuit board shown in FIG. 8 .

10 is a schematic cross-sectional view of a reinforcing sheet in 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 subjecting the reinforcing sheet shown in FIG. 11 to surface treatment.

13 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 thermally conductive reinforcing sheet shown in FIG. 12 .

FIG. 14 is a schematic cross-sectional view after installing a photosensitive chip in the slot of the composite circuit board shown in FIG. 13 .

FIG. 15 is a schematic cross-sectional view of the camera module obtained after filling the slots, the conductive posts and the photosensitive chips shown in FIG. 14 with thermally conductive material and installing the lens holder on the composite circuit board.

Description of main component symbols

Inner layer circuit substrate 10 Thermal conductive post 44

Base layer 11 Thermally conductive material 45

Inner circuit layer 12 Photosensitive chip 50

Insulation 13 Conductor 51

first protective layer 14 connection layer 52

First Adhesive Layer 20 Mirror Holder 60

Copper foil layer 21 Lens 61

First Copper Plating 22 Filter 62

Outer circuit layer 23 Second adhesive layer 70

Second protective layer 24 Composite circuit board 100, 200

Slot 25 Pad 230

Circuit board 30 Camera module 300, 400

Blind slot 33 Through hole 410

Thermal Reinforcement Sheet 40, 40’ First Mounting Area 421

Reinforcing sheet 41 Second installation area 422

Second copper plating layer 42 Thickness T1, T2

Surface treatment layer 43

The following specific embodiments will further illustrate the present application in conjunction with the above drawings.

Detailed ways

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. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the specification of the application are for the purpose of describing specific embodiments only, and are not intended to limit the application.

In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purpose, the following detailed description of the present application is made with reference to the accompanying drawings and preferred embodiments.

Referring to FIGS. 1 to 7 , an embodiment of the present application provides a method for preparing a composite circuit board 100 , and the method includes the following steps:

S11 , referring to FIG. 1 , the inner layer circuit substrate 10 is provided, and the surface of the inner layer circuit substrate 10 is covered with the first adhesive layer 20 and the copper foil layer 21 .

Wherein, the material of the first adhesive layer 20 may be commonly used pure glue.

In one embodiment, the inner layer circuit substrate 10 includes a base layer 11 , an inner circuit layer 12 disposed on the surface of the base layer 11 , an insulating layer 13 and a first protective layer 14 sequentially disposed on the surface of the inner circuit layer 12 . As shown in the figure, the inner layer circuit substrate 10 in this embodiment is a flexible double-sided circuit substrate, that is, the inner circuit layers 12 are provided on the two opposite surfaces of the base layer 11 . In another embodiment, the number of circuit layers in the inner circuit substrate 10 can also be changed. For example, at least one intermediate circuit layer (not shown in the figure) can be formed on the surface of each inner circuit layer 12 by a build-up process. ).

The material of the base layer 11 is insulating resin. Specifically, the material of the base layer 11 can be selected from epoxy resin (epoxyresin), polypropylene (PP), BT resin, polyphenylene oxide (PPO), polypropylene (polypropylene, PP), polyimide (polyimide, PI), polyethylene terephthalate (Polyethylene Terephthalate, PET) and polyethylene naphthalate (Polyethylene Naphthalate, PEN) and other resins kind.

The material of the insulating layer 13 is insulating resin, specifically, the material of the insulating layer 13 can be selected from epoxy resin, polypropylene, BT resin, polyphenylene ether, polypropylene, polyimide, polyethylene terephthalate One of resins such as polyester 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 cover film (CVL). The first protective layer 14 is used to prevent the inner circuit layer 12 from being oxidized or short-circuited by soldering.

S12, please refer to FIG. 2, electroplating on the surface of the copper foil layer 21 to form the first copper plating layer 22, and etching the copper foil layer 21 and the first copper plating layer 22 through the exposure and developing process to obtain the outer circuit layer 23, and then The second protective layer 24 is covered on the outer circuit layer 23 .

One of the outer circuit layers 23 is partially exposed to the second protective layer 24 to form two pads 230 . Each pad 230 is used for electrically connecting the photosensitive chip 50 (refer to FIG. 8 and FIG. 9 ). The second protective layer 24 may be a solder resist layer or a cover film (CVL). The second protective layer 24 is used to prevent the outer circuit layer 23 from being oxidized or short-circuited by soldering.

S13 , referring to FIG. 3 , at least one slot 25 is formed through the second protective layer 24 , the outer circuit layer 23 , the first adhesive layer 20 and the inner circuit substrate 10 , thereby obtaining the circuit board 30 .

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

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

S14 , please refer to FIGS. 4 to 6 , providing a thermally conductive reinforcing sheet 40 , including a reinforcing sheet 41 and a second copper plating layer 42 . The reinforcing sheet 41 is provided with a plurality of through holes 410 . The second copper plating layer 42 is disposed on the opposite surface of the reinforcing sheet 41 and fills in each of the through holes 410 .

Wherein, the width of the through hole 410 is 100-400 microns. 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 microns.

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, electroless target plating, nickel electroplating, or electroless nickel plating. The surface treatment layer 43 is used to prevent the oxidation of the second copper plating layer 42 .

In one embodiment, the total thickness of the thermally conductive reinforcing sheet 40 (ie, the sum of the thicknesses of the reinforcing sheet 41 , the second copper plating layer 42 and the surface treatment layer 43 ) is 50-400 μm. The thickness of the thermally conductive reinforcing sheet 40 is defined as the dimension of the thermally conductive reinforcing sheet 40 along the extending direction of the circuit board 30 . The width of the thermally conductive 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 can be prepared in the following manner:

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 through the reinforcing sheet 41 . Then, electroplating is performed on the surface of the reinforcing sheet 41 and in the through hole 410 to form the second copper plating layer 42 .

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

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

S15 , referring to FIG. 7 , stack the circuit board 30 , the second adhesive layer 70 and the thermally conductive reinforcing sheet 40 . After lamination, the outer circuit layer 23 with the solder pads 230 is located on the surface of the circuit board 30 away from the thermally conductive reinforcing sheet 40 , and the thermally conductive reinforcing sheet 40 corresponds to the slot 25 and the area of the circuit board 30 surrounding the slot 25 . Then, pressing is performed to connect the second adhesive layer 70 to the circuit board 30 and the thermally conductive reinforcing sheet 40 to obtain the composite circuit board 100 .

In this embodiment, after the composite circuit board 100 is obtained, the preparation method further includes:

S16 , please refer to FIG. 8 , the photosensitive chip 50 is placed in the slot 25 and mounted on the thermally conductive reinforcing sheet 40 , and the photosensitive chip 50 is electrically connected to the bonding pad 230 through the wires 51 .

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

S17 , please refer to FIG. 9 , a lens holder 60 is installed on the second protective layer 24 corresponding to the outer circuit layer 23 having the solder pads 230 , and the lens holder 60 is provided with a lens 61 and a filter opposite to the lens 61 62 , so that the filter 62 is located between the lens 61 and the photosensitive chip 50 , thereby obtaining the camera module 300 .

Referring to FIG. 7 , the present application also provides a composite circuit board 100 prepared by the above-mentioned preparation method. The composite circuit board 100 includes a circuit board 30 , a second adhesive layer 70 and a thermally conductive reinforcing sheet 40 that are 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 layer circuit substrate 10 , and the inner layer circuit substrate 10 includes a base layer 11 , an inner circuit layer 12 disposed on the surface of the base layer 11 , an insulating layer 13 and a first protective layer 14 sequentially disposed on the 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 stacked on the inner circuit substrate 10 in sequence. One of the outer circuit layers 23 is partially exposed to the second protective layer 24 to form two pads 230 . A slot 25 is formed in the circuit board 30 , 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 substrate 10 .

The thermally conductive reinforcing sheet 40 includes a reinforcing sheet 41 and a second copper plating layer 42 . The reinforcing sheet 41 is provided with a plurality of through holes 410 . The second copper plating layer 42 is disposed on the opposite surface of the reinforcing sheet 41 and fills in each of the through holes 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 solder pads 230 is located on the surface of the circuit board 30 away from the thermally conductive reinforcing sheet 40 , and the thermally conductive reinforcing sheet 40 corresponds to the slot 25 and the area of the circuit board 30 surrounding the slot 25 .

Please refer to FIG. 9 , the present application also provides a camera module 300 prepared by the above-mentioned preparation method. The camera module 300 includes the above-mentioned circuit board 100 , the photosensitive chip 50 and the lens holder 60 . The lens holder 60 is provided with a lens 61 and a filter 62 opposite to the lens 61 .

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

Compared with the photosensitive chip 50 mounted on the circuit board 30 in the prior art, the photosensitive chip 50 in the present application is mounted on the thermally conductive reinforcing sheet 40 . Since the thermally conductive reinforcing sheet 40 includes the reinforcing sheet 41 and the second copper-plated layer 42 , the reinforcing sheet 41 has high hardness, so it can effectively support the photosensitive chip 50 and avoid the increase in the rigidity of the circuit board 30 in the prior art. Circuit board 30 thickness. Therefore, the present application can effectively reduce the thickness of the composite circuit board 100 , so that the composite circuit board 100 is more suitable for use in thin and light electronic products. Furthermore, the heat generated by the photosensitive chip 50 can be conducted to the thermally conductive reinforcing sheet 40 and then dissipated to the outside by the thermally conductive reinforcing sheet 40 . Since the thermal conductivity of the material of the second copper-plated layer 42 is higher than that of the reinforcing sheet 41, the thermal conductivity of the thermally conductive reinforcing sheet 40 can be improved (that is, the thermally conductive reinforcing sheet 40 can have both high thermal conductivity and high rigidity), thereby enabling the composite circuit board 100 effective heat dissipation.

Another embodiment of the present application further provides a method for preparing a 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 , and details are not repeated here. Please refer to FIG. 10 to FIG. 15, after step S23, the preparation method further includes the following steps:

S24 , please refer to FIG. 10 to FIG. 12 , providing a thermally conductive reinforcing sheet 40 ′, including a reinforcing sheet 41 and a second copper plating layer 42 . The reinforcing sheet 41 is provided with a plurality of through holes 410 . The second copper plating layer 42 is disposed on the opposite surface of the reinforcing sheet 41 and fills in each of the through holes 410 .

The difference from the thermally conductive reinforcing sheet 40 is that in the thermally conductive reinforcing sheet 40 ′, a plurality of thermally conductive pillars 44 are further provided on the surface of one of the second copper plated layers 42 , and the thermally conductive pillars 44 can be made of the second copper plated layer 42 . It is formed by integral extension (that is, the material of the thermal conductive column 44 is also copper). The extending direction of the thermally conductive pillars 44 may be perpendicular to the surface of the second copper plating layer 42 . In one embodiment, the second copper plating layer 42 includes a first mounting area 421 and a second mounting area 422 disposed around the first mounting area 421 . The thickness T1 of the first mounting area 421 may be greater than the thickness T2 of the second mounting area 422 , so that the surface of the first mounting area 421 is protruded from the surface of the second mounting area 422 . The thermally conductive post 44 is disposed on the protruding surface of the first mounting area 421 .

In one embodiment, the protruding height of the first mounting area 421 compared to the second mounting area 422 is 50-200 microns.

In one embodiment, the thermally conductive reinforcing sheet 40' further includes a surface treatment layer 43 . The surface treatment layer 43 is disposed on the surface of the second copper plating layer 42 away from the thermally conductive pillars 44 . The surface treatment layer 43 may be formed by electroless gold plating, electroless nickel plating, electroless target plating, nickel electroplating, or electroless nickel plating. The surface treatment layer 43 is used to prevent the reinforcing sheet 41 from being oxidized.

In one embodiment, the thermally conductive reinforcing sheet 40' can be prepared in the following manner:

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 through the reinforcing sheet. Then, electroplating is performed on the surface of the reinforcing sheet 41 and in the through hole 410 to form the second copper plating layer 42 .

As shown in FIG. 11 , computer numerical control (CNC) processing is performed on the second copper plating layer 42. After processing, one of the second copper plating layers 42 forms a first mounting area 421 and a second mounting area 422 with different thicknesses , and the thermally conductive pillars 44 extending from the surface of the first mounting area 421 .

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

S25, referring to FIG. 13, the circuit board 30, the second adhesive layer 70 and the thermally conductive reinforcing sheet 40' are laminated. After lamination, the outer circuit layer 23 with the solder pads 230 is located on the surface of the circuit board 30 away from the thermally conductive reinforcing sheet 40', and the surface treatment layer 43 is located on the surface of the thermally conductive reinforcing sheet 40' away from the circuit board 30. The thermally conductive reinforcing sheet 40' corresponds to the slot 25 and the area of the circuit board 30 surrounding the slot 25, and the thermally conductive post 44 extends into the slot 25. Then, pressing is performed to connect the second adhesive layer 70 to the circuit board 30 and the thermally conductive reinforcing sheet 40' to obtain the composite circuit board 200.

More specifically, when the second copper plating layer 42 includes the first mounting area 421 and the second mounting area 422 with different thicknesses, the second adhesive layer 70 connects the circuit board 30 and the second mounting area 422 so that the protrudingly disposed Part of the first mounting area 421 also extends into the slot 25 .

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

S26 , please refer to FIG. 14 , place the photosensitive chip 50 in the slot 25 and mount it on the first mounting area 421 of the thermally conductive reinforcing sheet 40 ′, and electrically connect the photosensitive chip 50 to the bonding pads 230 through the wires 51 .

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

S27 , referring to FIG. 15 , a thermally conductive material 45 is filled between the slot 25 and the thermally conductive pillar 44 and between the photosensitive chip 50 and the thermally conductive pillar 44 . The thermally conductive material 45 can also cover at least part of the wires 51 .

In one embodiment, the distance between the slot 25 and the thermally conductive post 44 is 100-200 microns. The thermally conductive pillars 44 have a width of 100-500 microns. Wherein, the width of the heat-conducting column 44 is defined as the dimension of the heat-conducting column 44 along the extending direction of the circuit board 30 . The thermally conductive material 45 may be thermally conductive silica gel.

S28, install a lens holder 60 on the second protective layer 24 corresponding to the outer circuit layer 23 with the solder pads 230, and the lens holder 60 is provided with a lens 61 and a filter 62 opposite to the lens 61, so that the filter The sheet 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 also provides a composite circuit board 200 prepared by the above-mentioned preparation method. The composite circuit board 100 includes a circuit board 30, a second adhesive layer 70 and a thermally conductive reinforcing sheet 40' that are stacked in sequence. The second adhesive layer 70 connects the circuit board 30 and the thermally conductive reinforcing sheet 40'.

The thermally conductive reinforcing sheet 40' includes a reinforcing sheet 41 and a second copper plating layer 42. The reinforcing sheet 41 is provided with a plurality of through holes 410 . The second copper plating layer 42 is disposed on the opposite surface of the reinforcing sheet 41 and fills in each of the through holes 410 . The surface of one of the second copper plating layers 42 is further provided with a plurality of thermally conductive pillars 44 , and the thermally conductive pillars 44 may be formed by integrally extending from the second copper plating layer 42 . In one embodiment, the second copper plating layer 42 includes a first mounting area 421 and a second mounting area 422 disposed around the first mounting area 421 . The thickness T1 of the first mounting area 421 may be greater than the thickness T2 of the second mounting area 422 , so that the surface of the first mounting area 421 is protruded from the surface of the second mounting area 422 . The thermally conductive post 44 is disposed on the protruding surface of the first mounting area 421 . The thermally conductive 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 thermally conductive pillars 44 .

The outer circuit layer 23 with the solder pads 230 is located on the surface of the circuit board 30 away from the thermally conductive reinforcing sheet 40 ′, and the surface treatment layer 43 is located on the surface of the thermally conductive reinforcing sheet 40 ′ away from the circuit board 30 , and the thermally conductive reinforcing sheet 40 is connected to the slot. 25 and the area of the circuit board 30 surrounding the slot 25 corresponds. The thermally conductive post 44 extends into the slot 25 .

Please refer to FIG. 14 , the present application also provides a camera module 300 prepared by the above-mentioned preparation method. The camera module 300 includes the above-mentioned circuit board 200 , the photosensitive chip 50 and the lens holder 60 . The lens holder 60 is provided with a lens 61 and a filter 62 opposite to the lens 61 .

The photosensitive chip 50 is accommodated in the slot 25 and mounted on the thermally conductive reinforcing sheet 40 , and the photosensitive chip 50 is electrically connected to the bonding pad 230 through the wire 51 . The filter 62 is located between the lens 61 and the photosensitive chip 50 . A thermally conductive material 45 is filled between the slot 25 and the thermally conductive pillar 44 and between the photosensitive chip 50 and the thermally conductive pillar 44 . The thermally conductive material 45 can also cover at least part of the wires 51 .

In the camera module 400 of this embodiment, the heat generated by the photosensitive chip 50 can also be conducted to the thermally conductive column 44 and the ground layer (ie, the inner circuit layer 12 ) through the thermally conductive material 45 , so that the thermal conductivity of the thermally conductive reinforcing sheet 40 ′ can be improved. .

It can be understood that for those of ordinary skill in the art, various other corresponding changes and deformations can be made according to the technical concept of the present application, and all these changes and deformations should belong to the protection scope of the claims of the present application.

Claims (12)

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;

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.

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;

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.

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.

Images