CN108882567B

CN108882567B - Manufacturing method of PCB

Info

Publication number: CN108882567B
Application number: CN201810981738.9A
Authority: CN
Inventors: 纪成光; 王洪府; 白永兰; 袁继旺; 陈正清
Original assignee: Shengyi Electronics Co Ltd
Current assignee: Shengyi Electronics Co Ltd
Priority date: 2018-08-27
Filing date: 2018-08-27
Publication date: 2020-05-22
Anticipated expiration: 2038-08-27
Also published as: CN108882567A

Abstract

The invention relates to the technical field of circuit board production, and discloses a manufacturing method of a PCB, which comprises the following steps: s1, providing a multilayer board provided with blind grooves; s2, carrying out copper deposition and electroplating treatment on the multilayer board to metalize the groove wall and the groove bottom of the blind groove; s3, forming a groove with the depth smaller than that of the blind groove on the opening side of the blind groove of the multilayer board, and enabling the opening of the remaining blind groove to be located in the groove bottom area of the groove; and S4, forming a through groove at the bottom of the blind groove. The PCB with the plurality of step grooves, which is manufactured by the invention, enables the space of the step grooves on the PCB to be fully utilized, and the step grooves simultaneously comprise the metalized groove walls and the non-metalized groove walls, thereby being beneficial to further miniaturization of the PCB and being suitable for installation of components with special-shaped structures or special combined components.

Description

Manufacturing method of PCB

Technical Field

The invention relates to the technical field of circuit board production, in particular to a manufacturing method of a PCB.

Background

A Printed Circuit Board (PCB) is a provider of electrical connection of electronic components. Before the advent of printed circuit boards, interconnections between electronic components were completed by direct wire connections. In the present day, circuit panels exist only as effective experimental tools, and printed circuit boards have occupied an absolutely dominant position in the electronics industry.

In order to meet the requirements of high-density mounting or crimping of the printed circuit board, the multilayer printed circuit board is provided with a stepped groove so as to reduce the assembly volume. The current step groove design is mostly expressed as a first-order metallized or non-metallized step groove, is applied to microwave radio frequency products or is embedded into power amplifier components and parts at step positions, and the current design has the following defects:

1) the first-order stepped groove is single in shape and only can be used for assembling a single component, and the component mounting with a special-shaped structure cannot be realized;

2) the single metalized stepped groove or the single non-metalized stepped groove can not meet the special assembly requirements of components or integrate other more power amplification devices, and the components needing to be assembled such as an additional small chip or a power amplifier need to be attached to the surface of the printed circuit board, so that the assembly volume of the printed circuit board is increased.

3) The PCB structure which is formed by the non-metallization of the first-stage stepped groove and the metallization of the second-stage stepped groove and is required by components with special-shaped structures is difficult to process, unreasonable in manufacturing method and low in efficiency.

Therefore, a method for manufacturing a PCB is required to solve the above problems by manufacturing a stepped groove having a plurality of steps.

Disclosure of Invention

The invention aims to provide a method for manufacturing a PCB (printed circuit board), which is used for manufacturing the PCB with a plurality of step grooves, so that the space of the step grooves on the PCB can be fully utilized, and the step grooves simultaneously comprise metalized groove walls and non-metalized groove walls, thereby being beneficial to further miniaturization of the PCB and being suitable for installation of components with special-shaped structures or special combined components.

In order to achieve the purpose, the invention adopts the following technical scheme:

a manufacturing method of a PCB comprises the following steps:

s1, providing a multilayer board provided with blind grooves;

s2, carrying out copper deposition and electroplating treatment on the multilayer board to metalize the groove wall and the groove bottom of the blind groove;

s3, forming a groove with the depth smaller than that of the blind groove on the opening side of the blind groove of the multilayer board, and enabling the opening of the remaining blind groove to be located in the groove bottom area of the groove;

and S4, forming a through groove at the bottom of the blind groove.

As a preferable aspect of the present invention, the step S3 includes the step S31: and forming the initial groove bottom of the groove by depth-controlled milling of adjacent prepregs above the target copper layer in the multilayer board.

As a preferable aspect of the present invention, step S31 is followed by the steps of:

s32, performing laser ablation on the remaining prepreg above the target copper layer to expose the target copper layer;

and S33, removing the target copper layer by etching to form the final groove bottom of the groove.

As a preferable aspect of the present invention, the step S1 includes the steps of:

s11, providing an upper substrate, a prepreg and a lower substrate, wherein the upper substrate and the prepreg are respectively provided with a through groove;

s12, sequentially overlapping the upper substrate, the prepreg and the lower substrate to align the through grooves of the upper substrate and the prepreg;

and S13, pressing to obtain the multilayer board with blind grooves.

In a preferred embodiment of the present invention, the target copper layer and the copper layers above the target copper layer of the upper substrate are provided with first notches, and the first notches are provided in outer peripheral portions of the grooves.

As a preferable aspect of the present invention, between step S11 and step S12, the method further includes:

step S111, performing brown oxidation treatment on the upper substrate and the lower substrate;

further included between step S12 and step S13 is:

and S121, placing a glue resisting material in the through grooves of the upper substrate and the prepreg.

As a preferable scheme of the invention, the horizontal cross-sectional area of the groove is larger than that of the blind groove, and the horizontal cross-sectional area of the blind groove is larger than that of the through groove.

As a preferable aspect of the present invention, after step S2, the method includes:

step S21, tin plating the metalized groove wall;

correspondingly, after step S33, the method further includes:

and S34, removing tin from the part which is protected by tin plating in the step S21.

As a preferable scheme of the invention, a plurality of blind grooves are formed, a plurality of grooves are formed, and a plurality of through grooves are formed.

The invention has the beneficial effects that:

the space of the stepped groove on the PCB can be fully utilized by manufacturing the PCB with the stepped groove with the multistage steps; processing a target copper layer at the bottom of the groove by a laser ablation and etching process; the stepped groove simultaneously contains a metalized groove wall and a non-metalized groove wall, is beneficial to further miniaturization of the PCB, and is suitable for installation of components with special-shaped structures or special combined components.

Drawings

FIG. 1 is a flow chart of a method for fabricating a PCB according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a multi-layer board lamination process according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a copper deposition and electroplating process for a multilayer board according to an embodiment of the invention.

Fig. 4 is a schematic structural diagram illustrating a process of exposing a target copper layer according to an embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a final groove bottom process of etching and removing a target copper layer to form a groove according to an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a final PCB product according to an embodiment of the present invention.

In the figure:

1. a blind groove; 2. a multilayer board; 21. an upper substrate; 22. a prepreg; 23. a lower substrate; 3. a groove; 4. a through groove; 5. and (5) glue blocking materials.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

As shown in fig. 1, the present embodiment provides a flow chart of a method for manufacturing a PCB, which includes the following steps:

step one, a multilayer board 2 provided with blind grooves 1 is manufactured, and the structure schematic diagram is shown in fig. 2.

Specifically, an upper substrate 21, a prepreg 22, and a lower substrate 23 are provided, the upper substrate 21 is provided with a through groove, and the prepreg 22 is provided with a through groove having a similar size. The upper substrate 21 and the lower substrate 23 are browned. The upper substrate 21, the prepreg 22, and the lower substrate 23 are sequentially stacked such that the through grooves of the upper substrate 21 and the prepreg 22 are aligned. And the glue resisting material 5 is placed in the through grooves of the upper substrate 21 and the prepreg 22, so that the molten prepreg is prevented from flowing into the blind groove 1 during pressing, the size accuracy of the blind groove 1 is influenced, and the groove bottom surface of the blind groove 1 is prevented from being polluted.

In this embodiment, the substrate may be a single core board or a sub-board formed by pressing multiple core boards, or the core boards and/or the sub-boards may be selected according to design requirements to be combined, so as to obtain the number of copper layers meeting the requirements; in addition, the combination of the core board and/or the sub-board may be pressed into a laminated board in a certain step, or may be pressed together in a subsequent step.

Specifically, as shown in fig. 2, a copper layer at the bottom of a groove to be processed in the upper substrate is a target copper layer, an annular first notch is formed in the target copper layer and the copper layers above the target copper layer, the first notch is formed in the outer periphery of the groove, and the horizontal cross-sectional profile of the first notch is located at the periphery of the horizontal cross-sectional profile of the groove to be processed. The arrangement of the first notch enables the molten prepreg to fill the first notch during pressing in the subsequent processing process, and after the groove is formed, the prepreg and the base material at the first notch can form a non-metalized groove wall of the groove.

And pressing the upper substrate 21, the prepreg 22 and the lower substrate 23, wherein the lower substrate 23 blocks one side opening of the through groove to form a blind groove 1, so that the multilayer board 2 provided with the blind groove 1 is manufactured, and taking out the glue blocking material 5. The blind groove 1 can be provided with a plurality of blind grooves on the multilayer board.

And step two, carrying out copper deposition and electroplating treatment on the laminated multilayer board 2 to metalize the groove wall and the groove bottom of the blind groove 1, wherein the schematic structural diagram is shown in fig. 3. The surface mounting of the components is realized by the metallization of the groove wall, the signal shielding of the components is facilitated, the metallization of the groove bottom is realized, and the heat dissipation efficiency of the components is improved.

Step three, forming the groove 3, wherein the technological process is shown in figures 4-5.

Forming an initial groove bottom of a groove 3 by depth-controlled milling of adjacent prepregs above a target copper layer in the multilayer board 2, wherein the depth of the groove 3 is smaller than that of the blind groove 1, and the opening of the remaining blind groove 1 is positioned in the groove bottom area of the groove 3, and the structural schematic diagram is shown in fig. 4; then, performing laser ablation on the remaining prepreg above the target copper layer to expose the target copper layer, wherein after the prepreg is ablated, the metalized groove wall of the blind groove 1 forms a bulge on the surface of the target copper layer; plating tin on the metalized groove wall to be reserved subsequently, and preventing the subsequent etching process from damaging the non-target copper layer; the exposed target copper layer is removed by an etching process. At this time, it is emphasized that the raised channel wall copper is etched together with the target copper layer, and finally, the channel wall copper of the blind channel 1 is flush with the substrate below the target copper layer to form the final channel bottom of the groove 3, and the tin-plating protected portion is subjected to tin stripping operation. As shown in fig. 5, the groove wall of the groove 3 is formed by the prepreg and the base material at the location of the first notch, i.e. the groove wall of the groove 3 is not metallized.

The groove 3 can be provided with a plurality of grooves, the bottom of one groove 3 can comprise a plurality of blind grooves 1, and the horizontal cross-sectional area of the groove 3 is larger than that of the blind grooves 1. The groove wall of the groove 3 is not metallized, so that components can be sunk and assembled, and the assembly volume of the PCB is greatly reduced.

And step four, forming a through groove 4.

A through groove 4 is arranged at the bottom of the blind groove 1.

The through grooves 4 can be provided in plurality, and the horizontal cross-sectional area of the blind groove 1 is larger than that of the through groove 4.

Finally, a manufacturing method of the PCB according to the present invention is formed, and a schematic structural diagram of a final PCB product is processed, as shown in fig. 6. Recess 3, the horizontal cross sectional area of blind groove 1 and logical groove 4 reduces in proper order, form "T" type notch cutthroat, and simultaneously, the cell wall and the tank bottom of recess 3 are non-metallicized, the cell wall tank bottom metallization of blind groove 1, this kind of preparation method that makes the cell wall of recess 3 and tank bottom non-metallicization is more reasonable effective, can satisfy the preparation requirement of heterotypic structure components and parts, among the prior art has been solved, first order notch cutthroat is non-metallicized, this kind of structure of second order notch cutthroat metallization requires the drawback of processing difficulty, realize the subsides dress of components and parts of dysmorphism structure and multiple not unidimensional components and. The second-stage step groove metallization improves the power amplification efficiency of the components, improves the signal transmission speed and reduces the signal loss.

In addition, the method for manufacturing the PCB according to the present invention is simple and feasible, has mass production, can obtain the PCB provided with the multi-level stepped grooves, and is not limited to the three-level stepped grooves shown in the drawings of the present invention.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A manufacturing method of a PCB is characterized by comprising the following steps:

s1, providing a multilayer board provided with blind grooves;

s4, forming a through groove at the bottom of the blind groove;

step S1 includes the following steps:

s13, pressing to obtain a multilayer board with blind grooves;

the copper layer of the groove bottom of the groove to be processed of the upper substrate is a target copper layer, an annular first notch is formed in the target copper layer and the copper layers above the target copper layer, and the first notch is formed in the peripheral portion of the groove.

2. The method of fabricating a PCB of claim 1, wherein the step S3 includes the step S31: and forming the initial groove bottom of the groove by depth-controlled milling to the adjacent prepreg above the target copper layer in the multilayer board.

3. The method for manufacturing a PCB of claim 2, further comprising the following steps after the step S31:

and S33, removing the target copper layer through etching to form the final groove bottom of the groove.

4. The method for manufacturing a PCB of claim 1, further comprising between the step S11 and the step S12:

step S111 of performing browning treatment on the upper substrate and the lower substrate;

further included between step S12 and step S13 is:

and step S121, placing a glue resisting material in the through grooves of the upper substrate and the prepreg.

5. The method of claim 1, wherein a horizontal cross-sectional area of the groove is greater than a horizontal cross-sectional area of the blind via, and the horizontal cross-sectional area of the blind via is greater than a horizontal cross-sectional area of the through via.

6. The method for manufacturing a PCB according to claim 3, comprising after the step S2:

step S21, tin plating the metalized groove wall;

correspondingly, after step S33, the method further includes:

7. The method for manufacturing a PCB according to claim 5, wherein the blind slot is provided with a plurality of grooves, and the through slot is provided with a plurality of through slots.