CN115666019A

CN115666019A - Pressing method of asymmetric PCB

Info

Publication number: CN115666019A
Application number: CN202211281385.4A
Authority: CN
Inventors: 韩明; 黎钦源; 田玲
Original assignee: Guangzhou Guanghe Technology Co Ltd
Current assignee: Guangzhou Guanghe Technology Co Ltd
Priority date: 2022-10-19
Filing date: 2022-10-19
Publication date: 2023-01-31

Abstract

The application relates to a pressing method of an asymmetric PCB. The pressing method comprises the following steps: s1, pre-treating before plate stacking to obtain a plurality of interference treated plates; s2, pre-laminating the pre-processing boards to obtain an asymmetric PCB to be laminated; s3, overlapping even number of the asymmetric PCBs to be laminated into a symmetric structural plate; s4, putting the symmetrical structural plate into a press, and carrying out hot pressing according to a set program; s5, moving the symmetrical structural plates out of the laminating machine, and disassembling the symmetrical structural plates to obtain the asymmetrical PCB. This application is through treating the asymmetric PCB board of pressfitting with even number and folding into symmetrical structure board, and the effect that the stress can be reduced when the pressfitting to symmetrical structure board effectively improves the warpage degree of asymmetric PCB board, when not changing asymmetric PCB board structure, reduces its warpage, improves the yield of asymmetric PCB board, the bulk production of the asymmetric PCB board of being convenient for.

Description

Pressing method of asymmetric PCB

Technical Field

The application relates to the technical field of PCB manufacturing, in particular to a stitching method of an asymmetric PCB.

Background

Printed Circuit boards (PCBs for short) are important electronic components, which are support bodies of electronic components and carriers for electrical connection, and PCBs are gradually developed from single-layer PCBs to double-sided boards and multilayer boards, and are continuously developed toward high precision, high density and high reliability.

With the continuous update of electronic products and the arrival of high-speed transmission products such as 5G, the requirements for PCBs are also continuously increased, and in order to ensure signal strength, avoid stub effect and reduce cost, an even layer is usually optimized to an odd layer, for example, a 4-layer plate is optimized to a 3-layer structure. But conventional odd number layer PCB board is asymmetric structure, and when the PCB plate structure was asymmetric, because odd number layer PCB had the uneven problem of stress, lead to the PCB product to warp and surpass conventional management and control specification, brought very big puzzlement for the assembly of product preparation, management and control, shipment and customer end.

Therefore, in order to solve the warpage phenomenon of the asymmetric PCB during pressing, it is urgently needed to provide a pressing method of the asymmetric PCB, so as to improve the warpage phenomenon of the PCB and improve the quality of the manufactured PCB.

Disclosure of Invention

In order to overcome the problems in the related art, the application provides a pressing method of an asymmetric PCB, which can improve the bending and warping phenomena of odd laminated boards and improve the quality of the manufactured PCB.

The first aspect of the present application provides a stitching method for an asymmetric PCB, comprising the following steps:

s1, pre-treating plate materials before laminating to obtain a plate subjected to interference treatment;

s2, pre-laminating the pre-processing boards to obtain an asymmetric PCB to be laminated;

s3, overlapping even number of the asymmetric PCBs to be laminated into a symmetric structural plate;

s4, putting the symmetrical structural plate into a pressing machine, and carrying out hot pressing according to a set program;

s5, moving the symmetrical structural plates out of the laminating machine, and disassembling the symmetrical structural plates to obtain the asymmetrical PCB.

In one embodiment, in the step S4, the temperature increase rate is 1.5 to 2.5 ℃/min at the time of hot pressing.

In one embodiment, in the step S4, the temperature increase rate is 2 ℃/min during hot pressing.

In one embodiment, in the step S4, the pressure is 320-380PSI during hot pressing.

In one embodiment, in the step S4, the temperature decrease rate is 1 to 1.6 ℃/min during hot pressing.

In one embodiment, the step of moving the symmetrical structural board out of the laminating machine and disassembling the symmetrical structural board to obtain the asymmetrical PCB board comprises:

the temperature range of the symmetrical construction plates when removed from the press was maintained at 50-100 ℃.

In one embodiment, step S1 is preceded by:

cutting: selecting a core board, PP and copper foil, and cutting according to the design size;

drilling: drilling a plurality of positioning holes on the PP and the copper foil by using a drilling machine, and positioning when pressing;

making an inner layer pattern: coating, exposing, developing and etching the core plate according to design parameters to manufacture a pattern;

shooting: an automatic target machine is adopted to find a positioning target on the inner layer of the core plate by utilizing X-ray transmission, and a positioning hole is drilled on the positioning target through a drill cutter and is used for positioning during pressing;

browning: and carrying out browning treatment on the core plate by using browning liquid medicine.

In one embodiment, the step S2 pre-overlaps the pre-processed board to obtain a board to be laminated with an asymmetric PCB;

and laying copper on the edge of the inner part of the asymmetric PCB.

In one embodiment, the order of the asymmetric PCB in the vertical direction is: copper foil, PP and core board.

The technical scheme provided by the application has the following beneficial effects:

according to the laminating method of the asymmetric PCB, the even number of asymmetric PCBs to be laminated are laminated into the symmetric structural plate, the existing odd layer PCB is generally the asymmetric PCB, the reason is that the prepreg PP is arranged on the single side of the odd layer PCB and is influenced by the asymmetric plate structure, the prepreg PP shrinks after being laminated, and the plate warping is serious. Because the structure of the PCB is not changed, for example, the symmetrical structure is not achieved by increasing the number of layers, the input of raw materials of the PCB can be reduced to a certain extent, and the production cost of the PCB is reduced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The foregoing and other objects, features and advantages of the application will be apparent from the following more particular descriptions of exemplary embodiments of the application, as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the application.

Fig. 1 is a schematic flowchart illustrating a stitching method for an asymmetric PCB according to an embodiment of the present application;

fig. 2 is a stacked structure of a stitching method of an asymmetric PCB according to an embodiment of the present application;

fig. 3 is a stacked structure of a press-bonding method of an asymmetric PCB of the related art.

Reference numerals are as follows:

1. a core board; 2. PP; 3. copper foil; 4. and (3) a steel plate.

Detailed Description

Preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present application have been illustrated in the accompanying drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

Example one

Printed Circuit Boards (PCBs) are important electronic components, and are support bodies and electrical connection carriers for electronic components, and PCBs are gradually developed from single-layer PCBs to double-sided PCBs and multi-layer PCBs, and are continuously developed toward high precision, high density and high reliability.

see fig. 1 and 2.

The pressing method of the asymmetric PCB comprises the following steps:

s1, pre-treating a plate material before laminating to obtain a plate subjected to interference treatment;

the method comprises the steps of processing each plate material according to the production standard and size requirements, and obtaining a plurality of pre-processed plates after processing, wherein the pre-processed plates comprise a core plate, copper foil, PP and the like.

the order of the pre-lamination of the asymmetric PCB is as follows: the number of the core plates is set according to the layer number requirement of the asymmetric PCB, and the PCB obtained by laminating according to the pre-laminating sequence is the asymmetric PCB because only one side of the core plates is provided with the prepreg PP. The core plate is formed by pressing two layers of copper foils and PP arranged between the two layers of copper foils.

S3, overlapping an even number of asymmetric PCBs to be laminated into a symmetric structural plate;

the reason why the number of the asymmetric PCBs to be laminated of the symmetric structural plates is limited to be even, the number of specific even numbers is not limited, and the limitation can be made according to actual production, is that the reason why the number of the asymmetric PCBs to be laminated is limited to be even is that the structure of the asymmetric PCBs to be laminated is an asymmetric structure, and the number of the odd asymmetric PCBs to be laminated cannot reach the symmetric structure when being laminated, so that only the number of the asymmetric PCBs to be laminated is laminated and can be laminated into a symmetric structural plate, taking two asymmetric PCBs to be laminated as an example, one of the asymmetric PCBs to be laminated needs to be laminated after being turned over, so that the symmetric structure can be reached, as shown in FIG. 2, whereas the bending phenomenon of the asymmetric PCBs cannot be solved in the laminating process in the prior art through sequential lamination, as shown in FIG. 3, the asymmetric structural plates still exist.

If a plurality of asymmetric PCBs to be laminated are symmetrically laminated in pairs, and then are laminated into a symmetric structural plate along the vertical direction.

S4, putting the symmetrical structural plate into a pressing machine, and carrying out hot pressing according to a set program.

And S5, moving the symmetrical structural plate out of the laminating machine, and disassembling the symmetrical structural plate to obtain the asymmetrical PCB.

The beneficial effects of the embodiment of the application are as follows: according to the laminating method of the asymmetric PCB, the even number of asymmetric PCBs to be laminated are laminated into the symmetric structural plate, the existing odd layer PCB is generally of an asymmetric structure, the reason is that the prepreg PP is arranged on the single side of the odd layer PCB and is influenced by the asymmetric plate structure, the prepreg PP shrinks after being laminated, and the warping of the plate is serious. Because the structure of the PCB is not changed, for example, the symmetrical structure is not achieved by increasing the number of layers, the input of raw materials of the PCB can be reduced to a certain degree, and the production cost of the PCB is reduced.

Example two

The pressing method of the asymmetric PCB in the embodiment of the present application is further invented and designed for the pressing method of the asymmetric PCB in the first embodiment.

The pressing method of the asymmetric PCB comprises the following steps:

s4, putting the symmetrical structural plate into a press, and carrying out hot pressing according to a set program;

s5, moving the symmetrical structural plate out of the laminating machine, and disassembling the symmetrical structural plate to obtain the asymmetrical PCB.

Further, in step S4, the temperature rise rate is 1.5 to 2.5 ℃/min at the time of hot pressing. Preferably, the rate of temperature rise is 2 ℃/min. Under the temperature rise rate, the temperature rise is not fast or slow, the pressing of each layer can be controlled to be tighter, the effect is better, and the final temperature is preferably 210 ℃.

Further, in step S4, the pressure is 320-380PSI during hot pressing. Under the condition of the pressure range, the pressing effect can be ensured, and the pressing efficiency can be improved.

Further, in step S4, the temperature reduction rate is 1-1.6 ℃/min during hot pressing. Preferably, the cooling rate is 1.3 ℃/min. The cooling speed should not too fast nor too slow, too fast makes this circuit board that pressfitting has been good appear becoming flexible easily, counterpoint inaccurate, too slow then influence production efficiency.

Further, moving the symmetrical structural boards out of the laminating machine, disassembling the symmetrical structural boards, and obtaining the step of the asymmetrical PCB:

The beneficial effects of the embodiment of the application are as follows: the embodiment of the application has the advantages that through setting the heating speed and the cooling speed during hot pressing, the temperature rises slowly and slowly at the heating speed, and the pressing of each layer can be controlled better, so that the effect is better. Under this cooling rate, cooling speed is neither too fast nor too slow, can not make this circuit board that the pressfitting is good appear becoming flexible easily, and it is inaccurate to counterpoint, then can not influence production efficiency yet to can improve the effect of pressfitting.

EXAMPLE III

Before the step S1 in the first embodiment or the second embodiment, the following steps are further included:

drilling: drilling a plurality of positioning holes in the PP and the copper foil by using a drilling machine, and positioning when pressing;

target shooting: an automatic target machine is adopted to find a positioning target on the inner layer of the core plate by utilizing X-ray transmission, and a positioning hole is drilled on the positioning target through a drill cutter and is used for positioning during pressing;

browning: browning the core plate by using browning liquid medicine.

The following steps are then performed:

Further, pre-laminating the pre-processing board in S2 to obtain the front part of the asymmetric PCB to be laminated;

copper is laid on the edge of the interior of the asymmetric PCB, and the copper can be laid to improve the supporting force of the interior of the PCB.

In the step of S3, an even number of asymmetric PCBs to be laminated are laminated into a symmetric structural plate, steel plates can be placed between the asymmetric PCBs to be laminated and the asymmetric PCBs to be laminated to assist in lamination, the steel plates are placed on the outer sides of the bottom layer of asymmetric PCBs to be laminated and the top layer of asymmetric PCBs to be laminated to assist in lamination, the steel plates have a lamination assisting effect, bending can be reduced to a certain extent, the lamination leveling force is achieved, and on the other hand, the steel plates play an isolation effect when all layers of asymmetric PCBs in the symmetric structural plate are disassembled subsequently.

The beneficial effects of the embodiment of the application are as follows: pre-laminating the pre-processing board in S2 to obtain the front of the asymmetric PCB to be laminated; copper is laid on the edge of the interior of the asymmetric PCB, and the copper can be laid to improve the supporting force of the interior of the PCB.

Example four

And pressing the asymmetric PCB obtained by the pressing method of the symmetric PCB according to the first to third embodiments. Asymmetric PCB boards are typically odd-numbered boards.

The asymmetric PCB of the embodiment of the application is as follows along the vertical direction sequence: the number of layers of the asymmetric PCB is not limited, if the asymmetric PCB is a three-layer board, the copper foil, the PP and the core board are adopted, the core board is a double-sided core board, two layers are adopted on two sides of the core board, and one layer of copper foil is added to form the three-layer board.

The conventional odd-numbered layer board has an asymmetric structure as shown in fig. 3, and the PCB board having the asymmetric structure is cooled after the bonding process, and the PCB is bent due to different lamination tensions when the PCB board having the asymmetric structure is cooled down. And the greater the risk of bending a PCB having two different structures as the thickness of the PCB increases.

In view of the above situation, in the asymmetric PCB of the embodiment of the present application, the stacking order of the asymmetric PCB is the core board, PP, and copper foil;

as shown in fig. 2, the asymmetric PCB is laminated to form a symmetric structural board, and the symmetric structural board of the PCB with the symmetrical laminated structure can reduce the stress effect during lamination, thereby effectively improving the warpage of the PCB, and reducing the warpage of the PCB without increasing the number of layers of the PCB.

Further, this application treats the asymmetric PCB board of pressfitting, the top layer treats the outside of the asymmetric PCB board of pressfitting and places the steel sheet and assist the pressfitting at the lower floor, and the steel sheet plays pressfitting additional action, can reduce crooked phenomenon to a certain extent, has the pressfitting roughness.

Further, the number of the core boards is not limited in the embodiments of the present application and should be set according to practical applications, and for example, as shown in fig. 2, three layers of PCB boards with the number of the core boards set to 1 are illustrated.

Further, lay copper at the inside edge of asymmetric PCB board, lay the copper set up can promote the holding power of PCB inboard, and then can reduce the reject ratio when the PCB board pressfitting.

The beneficial effects of the embodiment of the application are as follows: this application carries out the pressfitting with asymmetric PCB board stack formation symmetrical structure board, current odd number layer PCB board is asymmetric structure usually, its reason is that odd number layer PCB board is unilateral to have prepreg PP, receive asymmetric plate structure influence, shrink behind prepreg PP pressfitting, it is serious to lead to the board warpage, and carry out the pressfitting with asymmetric PCB board stack formation symmetrical structure board, the effect of stress can be reduced when the pressfitting to symmetrical structure board, effectively improve the warpage degree of PCB board, improve the yield of PCB board, the bulk production of the asymmetric PCB board of being convenient for. Because the number of layers of the PCB is not increased, the investment of raw materials of the PCB can be reduced to a certain extent, and the production cost of the PCB is reduced.

The foregoing description of the embodiments of the present application has been presented for purposes of illustration and description and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A pressing method of asymmetric PCB board is characterized in that,

the method comprises the following steps:

2. A method for pressing an asymmetric PCB as recited in claim 1, wherein in the step S4, a temperature rise rate is 1.5 to 2.5 ℃/min during the hot pressing.

3. The method for pressing an asymmetric PCB as recited in claim 2, wherein in the step S4, the temperature rising rate is 2 ℃/min during the hot pressing.

4. The method for pressing an asymmetric PCB as recited in claim 1, wherein in the step S4, the pressure is 320-380PSI during the hot pressing.

5. A method for pressing an asymmetric PCB as recited in claim 1, wherein in the step S4, the cooling rate is 1-1.6 ℃/min during the hot pressing.

6. A method for pressing an asymmetric PCB as recited in claim 1, wherein the step of removing the symmetrical structural boards from the pressing machine and disassembling the symmetrical structural boards to obtain the asymmetric PCB comprises:

7. The method of pressing an asymmetric PCB as recited in claim 1,

the step S1 comprises the following steps:

manufacturing an inner layer pattern: coating, exposing, developing and etching the core plate according to design parameters to manufacture a pattern;

target shooting: an automatic target shooting machine is adopted to find a positioning target on the inner layer of the core plate by utilizing X-ray transmission, and a positioning hole is drilled on the positioning target through a drill for positioning during pressing;

browning: browning the core plate by using browning liquid medicine.

8. The method for pressing an asymmetric PCB according to claim 1, wherein:

s2, pre-laminating the pre-processing board to obtain a position before the asymmetric PCB to be laminated is obtained;

and laying copper on the edge of the inner part of the asymmetric PCB.

9. The method for pressing an asymmetric PCB according to claim 1, wherein:

the order of the asymmetric PCB along the vertical direction is as follows: copper foil, PP and core board.