阅读说明：本技术 一种钢片嵌入式ccm模组用线路板的制备方法 (Preparation method of circuit board for steel sheet embedded CCM module ) 是由 张成立 徐光龙 王强 李东海 茆昊奇 黄礼树 于 2019-09-25 设计创作，主要内容包括：一种钢片嵌入式CCM模组用线路板的制备方法,步骤：内层芯板制作；钢片贴合：将带胶的钢片贴合在内层芯板的芯片区域；绝缘层贴合：将半固化片贴合在内层芯板上,对应钢片位置的绝缘层预先开窗以避位钢片；贴合、压合铜箔：在半固化片表面贴一层铜箔,经压合,将内层芯板与外层铜箔通过半固化片粘接在一起；钻孔：沉镀铜；线路制作；阻焊制作。本发明工艺简单合理,制备的产品不但散热性能好、平整度高,而且变形小,解像率高,像糊不良低,有效提高了模组优良率。(A preparation method of a circuit board for a steel sheet embedded CCM module comprises the following steps: manufacturing an inner-layer core board; steel sheet fitting: attaching the steel sheet with the adhesive to the chip area of the inner core plate; laminating an insulating layer: laminating a prepreg on the inner core plate, and pre-windowing an insulating layer corresponding to the position of the steel sheet to avoid the steel sheet; laminating and pressing the copper foil: adhering a layer of copper foil on the surface of the prepreg, and bonding the inner core board and the outer copper foil together through the prepreg by pressing; drilling: depositing and plating copper; manufacturing a circuit; and (6) solder resist manufacturing. The method has simple and reasonable process, and the prepared product has the advantages of good heat dissipation performance, high flatness, small deformation, high resolution ratio and low image blurring, and effectively improves the excellent rate of modules.)

1. A preparation method of a circuit board for a steel sheet embedded CCM module is characterized by comprising the following steps:

1) manufacturing an inner-layer core plate: the inner core board adopts a double-sided soft board adhered with a covering film;

2) steel sheet fitting: attaching the steel sheet with the adhesive to the chip area of the inner core plate;

3) laminating an insulating layer: laminating an insulating layer prepreg on the inner core plate, and pre-windowing an insulating layer corresponding to the position of the steel sheet to avoid the steel sheet;

4) laminating and pressing the copper foil: adhering a layer of copper foil on the surface of the prepreg, and bonding the inner core board and the outer copper foil together through the prepreg by pressing;

5) drilling: drilling holes at positions needing interlayer conduction;

6) and (3) copper deposition and plating: the copper deposition is to deposit a conductive copper layer on the hole wall insulating layer, and the copper plating is to thicken the thickness of the hole copper layer and the thickness of the surface copper layer;

7) manufacturing a circuit;

8) and (6) solder resist manufacturing.

2. The method of claim 1, wherein: the size of the steel sheet in the step 2) is 0.04-0.06 mm larger than the single side of the chip, and the prepreg in the soft board area is windowed in advance.

3. The method of claim 1, wherein: the top surface of the insulating layer in the step 3) is higher than the height of the steel sheet, and the windowing size is 0.14-0.16 mm larger than that of a single side of the steel sheet.

4. The method of claim 1, wherein: the drilling hole in the step 5) is a through hole or a blind hole.

5. The method of claim 1, wherein: the circuit manufacturing of the step 7) is to press a film → expose → develop → etch → remove the film.

6. The method of claim 1, wherein: the solder mask manufacturing in the step 8) is solder mask silk screen printing → solder mask pre-baking → solder mask exposure → solder mask developing → solder mask curing.

7. The method of claim 1, wherein: the thickness of the copper deposition plating in the step 6) is 0.3-1.0 μm.

8. The method of claim 1, wherein: the prepregs in the step 3) and the step 4) are made of hard board epoxy resin and glass fiber cloth.

Technical Field

The invention belongs to the technical field of circuit board manufacturing, and relates to a method for manufacturing a circuit board for a CCM module.

Background

With the increasing demand for quality of life, imaging and lighting are essential for life, and cameras and video cameras are also being miniaturized, reduced in power consumption, and reduced in cost.

CCM is a short name for a Camera Module (CMOS Camera Module), is a core device used in various new-generation portable Camera devices, and has advantages of miniaturization, low power consumption, low cost, and high image quality compared with a conventional Camera system. However, as the number of pixels increases, the requirements for the circuit board also increase. The conventional circuit board for a high pixel CCM module is manufactured as shown in FIG. 1, and the process comprises the following steps: the inner core soft board 10 is manufactured → the insulating layer 30 is attached → the copper foil 40 is attached, pressed → the hole 50 is drilled → the copper 60 is plated by deposition → the circuit is manufactured (film pressing, exposure, development, etching, film removal) → the solder resist 70 is manufactured. The prepared circuit board chip 80 is assembled as shown in fig. 3, and the conventional preparation method has the following defects:

firstly, the circuit board of a camera module is required to be thinner, but the rigidity and the thickness of the product are in inverse proportion;

secondly, the rigid-flex board needs to use a low-flow prepreg, the rigidity and Young modulus of the prepreg are limited, the area of a chip is large for high pixels, and the product deformation is required to be small in the assembling process, so that the expected resolution ratio can be obtained, and the generation of poor image blurring is reduced;

thirdly, the chip is attached to the surface of the solder mask, and the solder mask surface has height difference which can influence the attachment flatness of the chip;

fourthly, the chip area is large, and the bottom heat dissipation is not good.

Through looking up, chinese patent 'a CCM camera module circuit board structure and CCM camera' that current patent number is 201710357932.5, wherein, the CCM camera module circuit board structure includes the circuit board main part and sets up the high temperature resistant deformation strengthening layer of circuit board main part surface and pad windowing homonymy, sensitization IC sets up high temperature resistant deformation strengthening layer. This structure is through setting up high temperature resistant deformation strengthening layer in the circuit board main part, carries on sensitization IC and base on the high temperature resistant deformation strengthening layer, rely on the high temperature resistant characteristic of high temperature resistant deformation strengthening layer improves resistant deformability to realize the surfacing of circuit board, nevertheless add high temperature resistant deformation strengthening layer, will increase the thickness of circuit board certainly, influence heat dissipation, the cost of manufacture also increases to some extent moreover.

Therefore, a new method for manufacturing a circuit board for a high-pixel CCM module needs to be developed to meet the production requirement.

Disclosure of Invention

The invention aims to solve the technical problem of providing the method for preparing the circuit board for the steel sheet embedded CCM module, which has the characteristics of thin thickness, good flatness and good heat dissipation effect, and has simple and reasonable process and low cost.

The technical scheme adopted by the invention for solving the technical problems is as follows: a preparation method of a circuit board for a steel sheet embedded CCM module is characterized by comprising the following steps:

1) manufacturing an inner-layer core plate: the inner core board adopts a double-sided soft board adhered with a covering film;

2) steel sheet fitting: attaching the steel sheet with the adhesive to the chip area of the inner core plate;

3) laminating an insulating layer: laminating an insulating layer prepreg on the inner core plate, and pre-windowing an insulating layer corresponding to the position of the steel sheet to avoid the steel sheet;

4) laminating and pressing the copper foil: adhering a layer of copper foil on the surface of the prepreg, and bonding the inner core board and the outer copper foil together through the prepreg by pressing;

5) drilling: drilling holes at positions needing interlayer conduction;

6) and (3) copper deposition and plating: the copper deposition is to deposit a conductive copper layer on the hole wall insulating layer, and the copper plating is to thicken the thickness of the hole copper layer and the thickness of the surface copper layer;

7) manufacturing a circuit;

8) and (6) solder resist manufacturing.

As an improvement, the size of the steel sheet in the step 2) is 0.04-0.06 mm larger than the single side of the chip, and an insulating layer in a soft board area is windowed in advance.

As an improvement, the top surface of the insulating layer in the step 3) is higher than the height of the steel sheet, and the windowing size is 0.14-0.16 mm larger than that of a single side of the steel sheet.

Preferably, the thickness of the deposited copper in the step 6) is 0.3-1.0 μm.

Preferably, the prepregs in step 3) and step 4) are made of hard board epoxy resin and fiberglass cloth.

And 5) improving the drilling hole in the step 5) to be a through hole or a blind hole.

Further, the step 7) of circuit fabrication refers to film pressing → exposure → development → etching → film removal.

Finally, the solder mask manufacturing in the step 8) is solder mask silk screen printing → solder mask pre-baking → solder mask exposure → solder mask developing → solder mask curing.

Compared with the prior art, the invention has the advantages that: the chip area of the inner core plate is attached to the steel sheet, the chip is directly attached to the steel sheet, the surface is smooth, the heat dissipation capacity is improved, meanwhile, the strength of the steel sheet determines the deformation of the chip, and the deformation of the steel sheet in a high-temperature environment can be ignored after the steel sheet is subjected to a module assembly process; in addition, the steel sheet adopts an embedded process, so that the thickness of the steel sheet cannot exceed the ejection resistance welding thickness, and the height of the module cannot be increased. The method has simple and reasonable process, and the prepared product has the advantages of good heat dissipation performance, high flatness, small deformation, high resolution ratio and low image blurring, and effectively improves the excellent rate of modules.

Drawings

FIG. 1 is a process flow diagram of a conventional manufacturing method, in which (1) an inner core board is manufactured, (2) an insulating layer is attached,

(3) the copper foil is bonded and pressed, (4) drilling is performed, (5) copper deposition and plating is performed, (6) circuit manufacturing is performed, and (7) solder resist manufacturing is performed;

FIG. 2 is a process flow diagram of the method for manufacturing the circuit board for the high-pixel CCM module, wherein (1) the inner core board is manufactured, (2) the steel sheet is attached, (3) the insulating layer is attached, (4) the copper foil is attached and pressed, (5) the hole is drilled, (6) the copper is deposited, and (7) the solder mask is manufactured;

FIG. 3 is a chip assembly diagram of the wiring board prepared in FIG. 1;

fig. 4 is a chip assembly diagram of the wiring board prepared in fig. 2.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

As shown in fig. 2 and 4, a method for manufacturing a circuit board for a steel sheet embedded high-pixel CCM module comprises the following steps:

1) manufacturing an inner-layer core board 1: the inner core board 1 adopts a double-sided soft board adhered with a covering film;

2) and (3) steel sheet 2 fitting: attaching the steel sheet 2 with the adhesive to the chip area of the inner core plate 1; the size of the steel sheet 2 is 0.05mm larger than that of the single side of the chip 8, so that the finished chip 8 can be completely attached to the steel sheet 2 without suspension;

3) and (3) laminating of the insulating layer: laminating a prepreg of hard board epoxy resin and glass fiber cloth serving as an insulating layer 3 on the inner core plate 1, pre-windowing the insulating layer corresponding to the position of the steel sheet 2 to avoid the steel sheet 2, wherein the windowing size is 0.15mm larger than that of a single side of the steel sheet 2; the top surface of the insulating layer 3 is higher than the steel sheet 2; of course, other commonly used prepregs in the technical field can also be adopted as the prepreg;

4) laminating and pressing the copper foil: adhering a layer of pure copper foil 4 on the surfaces of the epoxy resin and glass fiber cloth prepregs, and bonding the inner core plate 1 and the outer pure copper foil 4 together through the epoxy resin and the glass fiber cloth prepregs by pressing;

5) drilling: drilling a hole 5 at a position needing interlayer conduction, wherein the hole 5 can be a through hole or a blind hole;

6) and (3) copper deposition and plating: the copper deposition is to deposit a conductive copper layer 6 with the thickness of 0.3-1.0 μm on the hole wall insulating layer; the copper plating is to thicken the thickness of the hole copper layer and the thickness of the surface copper layer;

7) and (3) circuit manufacturing: specifically, the circuit layer 9 is manufactured, and the finger pressing film → the exposure → the development → the etching → the film removal is carried out; this is a conventional process;

8) solder resist preparation: the solder resist layer 7 is manufactured by the conventional process including the steps of solder resist screen printing → solder resist pre-baking → solder resist exposure → solder resist development → solder resist curing.

Finally, the chip 8 is directly attached to the steel sheet.

The advantages obtained by the invention are:

firstly, directly attaching a chip to a steel sheet, determining the deformation of the chip by the strength of the steel sheet, and neglectably deforming the steel sheet in a high-temperature environment through a module assembly process;

secondly, selecting materials for the rigid-flexible printed circuit board according to the conventional method, and improving the strength and Young modulus of the product without adopting special materials;

thirdly, the chip is directly attached to the steel sheet, so that the heat dissipation capacity is increased;

fourthly, the steel sheet adopts an embedded process, the thickness of the steel sheet cannot exceed the ejection resistance welding thickness, and compared with the traditional structure, the height of the module cannot be increased, and even the height of the module can be reduced;

fifthly, the chip is attached to the surface of the steel sheet, the surface is smooth, and no height difference exists when the chip is attached;

and sixthly, the chip is attached to the steel sheet, so that the deformation is small, the resolution ratio is high, the image blur is low, and the excellent rate of the module is effectively improved.