CN111385962A

CN111385962A - PCB and preparation method thereof

Info

Publication number: CN111385962A
Application number: CN201811643503.5A
Authority: CN
Inventors: 曾梅燕; 王水娟
Original assignee: Shengyi Technology Co Ltd
Current assignee: Shengyi Technology Co Ltd
Priority date: 2018-12-29
Filing date: 2018-12-29
Publication date: 2020-07-07

Abstract

The invention provides a PCB and a preparation method thereof, wherein the periphery of the PCB is processed into a technical edge with a copper foil layer. The PCB process edge provided by the invention is provided with the copper foil layer, on one hand, the copper foil layer can play a role in physical fixation, and the flowing glue can be uniform due to the copper foils arranged on the periphery of the PCB; and on the other hand, the copper foil has certain stress contraction, so the design of keeping the copper foil layer can play a role in balancing the flowing glue stress pulling in the pressing plate process, thereby solving the problems of large size expansion and contraction of the PCB after the pressing plate, poor alignment in subsequent processing, poor matching of punching, poor workpiece feeding precision and the like.

Description

PCB and preparation method thereof

Technical Field

The invention belongs to the field of PCB preparation, and relates to a PCB and a preparation method thereof.

Background

PCB multiply wood pressfitting because influence such as clamp plate gummosis and material are heated can appear the size harmomegathus problem, leads to the PCB image, and counterpoint such as hole is not accurate, can't beat the rivet, supporting not neat scheduling problem, influences follow-up PCB and counterpoints and process and go up a class. The design of the board edge image of present PCB clamp plate core board is mainly copper PAD distribution or does not have the copper design, and such design can not improve the great problem of panel size harmomegathus behind the PCB clamp plate, especially glues the content high, and the board that flows to glue is big, and the size harmomegathus is bigger, to some size harmomegathus, and the higher PCB processing of counterpoint requirement, appears the counterpoint easily and inaccurately, and the drilling precision is not enough, can't punch supporting and influence the accurate scheduling problem of going up of follow-up customer.

CN107466164A discloses a PCB board pre-drilling method for overcoming the problem of shrinkage and expansion, comprising the following steps: s1, firstly drilling two 2.0mm guide holes in a groove before drilling, then pre-drilling 4 expanding punched holes at an R angle position by using a 0.8mm drill bit, and removing redundant positions of the R angle; s2, drilling off the redundant R-angle part at the edge of the slot hole by using a 0.8mm drill bit, and removing the R-angle area after pre-drilling. The invention solves the series problems of copper deposition and plate milling after the expansion and shrinkage of the PCB, but the invention does not fundamentally solve the expansion and shrinkage problems of the PCB. CN106572600A discloses a novel PCB linear expansion and contraction control method, which comprises the following steps: engineering design, namely manufacturing engineering data according to the requirements of a customer drawing, finding out the expansion and contraction values of the historical PCB which accords with the information comparison principle by using the established expansion and contraction database according to the customer data through the information comparison principle, and applying the expansion and contraction values to the currently processed PCB design to manufacture the engineering data; manufacturing a PCB, manufacturing the PCB according to engineering data manufactured by engineering design, collecting the work station data information and the expansion and contraction value of the PCB processed at present in the manufacturing process, and storing the work station data information, the expansion and contraction value, the design information and the material information of the PCB processed at present in an expansion and contraction database for reference when the PCB is designed and compared later; detecting, namely detecting the manufactured PCB, judging whether the finished PCB is qualified or not, and manufacturing the PCB in large batch if the finished PCB is qualified; the invention can prevent and control the PCB core board expansion and shrinkage problem in advance, but the expansion and shrinkage database applied in the invention needs to be established in advance, and a great deal of time and energy are needed to establish the expansion and shrinkage database.

Therefore, there is a need to develop a new PCB to solve the problem of PCB expansion and contraction.

Disclosure of Invention

The invention aims to provide a PCB and a preparation method thereof; the PCB provided by the invention has extremely small expansion and contraction, and further improves the drilling alignment precision, so that the PCB provided by the invention can well meet the application requirements.

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

in a first aspect, the invention provides a PCB, wherein the periphery of the PCB is processed into a technical edge with a copper foil layer.

In the preparation process of the PCB in the prior art, in order to ensure the efficiency and quality in the PCB assembly process, the PCB is provided with a process edge, and due to the expansion and shrinkage problem of copper foil, a person skilled in the art generally abandons a copper foil layer and adopts a copper PAD design or a copper-free design; and on the other hand, the copper foil has certain stress contraction, so the design of keeping the copper foil layer can play a role in balancing the flowing glue stress pulling in the pressing plate process, thereby solving the problems of large size expansion and contraction of the PCB after the pressing plate, poor alignment in subsequent processing, poor matching of punching, poor workpiece feeding precision and the like.

The PCB is a multilayer board, the invention only needs to ensure that the process edges have copper foil layers, the rest parts are not limited at all, and any applicable PCB in the prior art can adopt the method of the invention to solve the problem of expansion and shrinkage of the PCB. In a PCB, the PCB is generally divided into a circuit pattern area (PCB pattern area) and a non-circuit pattern area, the non-circuit pattern area is also called a process edge, and no circuit is distributed in the non-circuit pattern area, and the non-circuit pattern area is configured to improve assembly efficiency and quality in the PCB manufacturing process.

Preferably, the PCB board comprises a PCB pattern area and a technical edge with a copper foil layer positioned around the PCB pattern area.

Preferably, the width of the technical edge is 10-50mm, such as 12mm, 15mm, 20mm, 25mm, 28mm, 30mm, 32mm, 35mm, 38mm, 40mm, 42mm, 45mm, 48mm, etc.

Preferably, the copper foil layer has a gas guiding groove.

Since a small amount of gas may be generated during the lamination process, a gas guide groove is provided in the copper foil layer.

Preferably, the technology limit includes a plurality of processing portion that end to end links to each other in proper order, be provided with at least one air guide groove on the copper foil layer of processing portion.

According to the requirement, any position in the peripheral area of the PCB can be selected to be processed into a technical edge. If the PCB described in the present invention has a polygonal structure, the process edge is also polygonal, and at this time, the process edge can be expressed as being composed of a plurality of processing parts connected end to end in sequence.

Each side of the technological side of the polygonal structure is provided with at least one air guide groove; in the invention, the shape of the air guide groove is not limited, and the air guide groove can be a strip-shaped air guide groove, a circular air guide groove or a grid-shaped air guide groove, and can be adopted as long as the application requirements can be met.

Preferably, the width of the air guide groove is 1cm or more, for example, 1.5cm, 2cm, 3cm, 4cm, 6cm, or the like.

In a second aspect, the present invention provides a method for manufacturing a PCB board according to the first aspect, the method comprising the steps of: and sequentially cutting, drilling, copper deposition and electroplating, exposure and development, etching and washing, browning, laminating, pressing and manufacturing an outer PCB pattern on the copper-clad laminate to obtain the PCB.

Wherein, the film pattern used in the exposure and development process has a process edge structure.

The PCB is prepared from a copper clad laminate, and the copper clad laminate comprises a copper clad layer before the PCB is prepared.

In the preparation process of the conventional PCB in the prior art, unnecessary copper foil is usually removed in the etching and water washing process, and in the preparation method, the shape of the film graph is changed to enable the film graph to have a process edge structure, so that the copper foil layer in the process edge structure can be reserved in the etching and water washing process; according to the invention, the PCB can be obtained only by changing the film picture during the preparation of the PCB.

The thickness of the copper foil layer of the process edge is not limited, and the copper foil layer used by the copper foil clad laminate which can be processed into the PCB in the prior art can meet the application requirement.

Compared with the prior art, the invention has the following beneficial effects:

(1) the PCB process edge provided by the invention is provided with the copper foil layer, on one hand, the copper foil layer can play a role in physical fixation, and the flowing glue can be uniform due to the copper foils arranged on the periphery of the PCB; on the other hand, the copper foil also has certain stress shrinkage, so that the design of the retained copper foil layer can play a role in balancing the gumming stress pulling in the pressing plate process, thereby solving the problems of large size expansion and shrinkage of the PCB after pressing plate, poor alignment in subsequent processing, poor matching of punching, poor loading precision and the like;

(2) the size expansion and shrinkage of the PCB provided by the invention is within a range of +/-200 ppm (percentage), and the application requirements can be well met.

Drawings

Fig. 1 is a schematic structural diagram of a PCB provided in the present invention.

1-a PCB board; 101-a PCB graphics area; 102-process edge.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

As shown in fig. 1, the present embodiment provides a PCB board, which is composed of a PCB pattern area 101 and a process edge 102.

Wherein, technology limit width is 10mm, comprises four end to end interconnect processing portion, and processing portion has the copper foil layer, is provided with 2 air guide grooves that the width is 5cm on the copper foil layer.

The preparation method comprises the following steps: and sequentially cutting, drilling, copper deposition and electroplating, exposure and development, etching and water washing, browning, laminating, pressing and manufacturing an outer layer PCB pattern on the copper-clad laminate to obtain the PCB.

Example 2

Wherein, technology limit width is 50mm, comprises four end to end interconnect processing portion, and processing portion has the copper foil layer, is provided with 5 air guide grooves that the width is 2cm on the copper foil layer of processing portion.

In the preparation process of the prepared PCB, the film graph has a process edge structure, so that the copper foil layer in the process edge is reserved in the etching and water washing process.

Examples 3 to 5

The only difference from example 1 is that in this example, the width of the process edge is 20mm (example 3), 25mm (example 4), 40mm (example 5).

Example 6

The only difference from embodiment 1 is that in this embodiment, 1 circular hole type air guide groove with a diameter of 1cm is provided on the copper foil layer of each processing portion.

Comparative example 1

The only difference from example 1 is that in this comparative example, the film pattern used has no process edge structure, and the copper foil in the process edge is removed during the etching water washing, i.e., comparative example 1 provides a PCB board having a process edge structure without a copper foil layer.

Comparative example 2

The only difference from example 2 is that in this comparative example, the film pattern used has no process edge structure, and the copper foil in the process edge is removed during the etching water washing, i.e., comparative example 1 provides a PCB board having a process edge structure without a copper foil layer.

Performance testing

The PCB boards provided in examples 1 to 6 and comparative examples 1 to 2 were subjected to a performance test by the following method:

(1) collapsible size and collapsible ratio: measuring the size of the PCB with the size of more than 250mm before and after the lamination by using an image measuring instrument with the measuring accuracy of more than 0.01mm, and then calculating the expansion and contraction size and the expansion and contraction rate.

The results of the tests on examples 1-6 and comparative examples 1-2 are shown in Table 1:

TABLE 1

According to the embodiment and the performance test, the expansion and contraction of the PCB can meet the size expansion and contraction standard, and meanwhile, the expansion and contraction of the PCB can improve the alignment precision of drilling holes, so that the subsequent processing and application of the PCB are facilitated.

The applicant states that the present invention is illustrated by the above embodiments of the PCB and the method for manufacturing the same, but the present invention is not limited to the above process steps, i.e. it does not mean that the present invention must rely on the above process steps to be implemented. It will be apparent to those skilled in the art that any modification of the present invention, equivalent substitutions of selected materials and additions of auxiliary components, selection of specific modes and the like, which are within the scope and disclosure of the present invention, are contemplated by the present invention.

Claims

1. The PCB is characterized in that the periphery of the PCB is processed into a technical edge with a copper foil layer.

2. The PCB board of claim 1, wherein the PCB board comprises a PCB pattern area and a process edge with a copper foil layer located around the PCB pattern area.

3. The PCB board of claim 1 or 2, wherein the width of the technical edge is 10-50 mm.

4. The PCB board of any of claims 1-3, wherein the copper foil layer has an air-conducting slot.

5. The PCB board of claim 4, wherein the craft edge comprises a plurality of processing portions connected end to end in sequence, and the copper foil layer of the processing portion is provided with at least one air guide groove.

6. The PCB board of claim 4 or 5, wherein the width of the air guide groove is more than 1 cm.

7. A method of manufacturing a PCB board as claimed in any of claims 1-6, wherein the method comprises the steps of: sequentially cutting, drilling, copper deposition and electroplating, exposure and development, etching and water washing, browning, laminating, pressing and manufacturing an outer PCB pattern on the copper-clad laminate to obtain the PCB;