CN101547555A

CN101547555A - Printed circuit board

Info

Publication number: CN101547555A
Application number: CN200910083459A
Authority: CN
Inventors: 罗美琴
Original assignee: Fujian Star Net Communication Co Ltd
Current assignee: Ruijie Networks Co Ltd
Priority date: 2009-05-05
Filing date: 2009-05-05
Publication date: 2009-09-30
Anticipated expiration: 2029-05-05
Also published as: CN101547555B

Abstract

The invention relates to a printed circuit board. The printed circuit board comprises an inner signal layer and an outer signal layer which are isolated by a medium layer. The inner signal layer comprises a signal line region provided with a signal line pattern and a blank region outside the signal line region, wherein the blank region is provided with a balance weight used for supporting the medium layer on the two sides of the inner signal layer in the press-in process of the printed circuit board. Because of the adopted technical means that the balance weight is arranged in the blank region of the inner signal layer to support the medium layer, the method reduces the abrupt thickness changes in the signal layers, allows the medium layer to tend to bear balance stress in the press-in process, and reduces or even avoids local buckling deformation of the printed circuit board, thereby improving the quality and reliability of the finished product of the printed circuit board.

Description

Printed circuit board (PCB)

Technical field

The present invention relates to the printed circuit board arrangement designing technique, relate in particular to a kind of printed circuit board (PCB).

Background technology

Printed circuit board (PCB) (Printed Circuit Board; Hereinafter to be referred as: being the supporter of electronic component PCB), is the common component in the integrated circuit.For improving space availability ratio, existing PCB is the multilayer design usually, and Fig. 1 is the side-looking structural representation of a kind of multilayer board in the prior art.This multi-layer PCB is made up of copper-clad plate 10, dielectric layer 20 and top layer copper sheet 30.PCB shown in Figure 1 is typical six layer signal layer structure, i.e. two copper-clad plates 10, two surperficial copper sheets of base material 8 separately can form four layers of internal layer signals layer 1, and outermost two top layer copper sheets 30 can form two outer signals layers 2.Copper-clad plate 10 also claims copper clad laminate, is the board-like material that constitutes with hot pressing mode formation Copper Foil at base material 8 one or both sides.Each layer copper sheet can form the holding wire pattern of required form by metal etch process.

Multi-layer PCB often needs twice above holding wire pattern etch operation, is that example illustrates that the typical production of multi-layer PCB is with above-mentioned six layers of PCB: at first carry out etching on the copper sheet on copper-clad plate two sides, form the internal layer holding wire; With made between two copper-clad plates of internal layer holding wire respectively and the outside all with dielectric layer, promptly isolated with prepreg (Prepreg), put the top layer copper sheet at outermost two prepreg peripheral hardwares, prepreg can be described as adhesive sheet (bonding sheet) again, can be contained resin pickup and is formed through baking by glass fibre or other fiber; By hot pressing mode the sandwich construction that forms is carried out pressing subsequently; Top layer copper sheet to both sides carries out etching formation surface layer signal line at last.

In carrying out research process of the present invention, the inventor finds that local buckling deformation takes place existing multilayer board easily in manufacturing process, its concrete reason is: each layer signal line is to be used to connect electronic component, therefore the holding wire pattern requires to set according to the laying of electronic component, holding wire lay the density inequality, even can occur need not laying signal wire white space 4, Fig. 2 is the plan structure schematic diagram of multilayer board in the prior art, Fig. 3 is the partial side TV structure schematic diagram of multilayer board shown in Figure 2, and signals layer has comprised holding wire zone 3 and white space 4.As shown in Figure 3, lay when inhomogeneous when each layer signal line, cause each layer thickness inhomogeneous, the position projection of holding wire is arranged and thickness is big, the position of no signal line is recessed and thickness is little.When the interval between the copper sheet that forms holding wire is excessive, sandwich construction is being carried out in the process of pressing, can cause each layer structure discontinuity on its whole plane, as shown in Figure 3, there is the position of holding wire stressed big, the position of no signal line is stressed little.Planarization during the multi-layer PCB pressing after balance and the pressing is a greater impact, and phenomenons such as buckling deformation very easily take place, and has influenced end product quality and the reliability of PCB.

Summary of the invention

The purpose of this invention is to provide a kind of printed circuit board (PCB), reduce even avoid in the print circuit plates making process, occurring the buckling deformation phenomenon, improve the end product quality and the reliability of printed circuit board (PCB).

For achieving the above object, the invention provides a kind of printed circuit board (PCB), comprise by isolated internal layer signals layer of dielectric layer and outer signals layer, described internal layer signals layer comprises holding wire zone and the holding wire zone white space in addition that is provided with the holding wire pattern, wherein: be provided with balance weight in the described white space, be used for supporting the dielectric layer of described internal layer signals layer both sides in the pressing process of described printed circuit board (PCB).

By above technical scheme as can be known, the present invention adopts the white space at the internal layer signals layer that the technological means that balance weight comes supporting medium layer is set, the abrupt changes in thickness of signals layer is reduced, it is stressed even that dielectric layer is tending towards in the pressing process, the phenomenon that can reduce even avoid PCB local buckling deformation to occur takes place, thereby improves end product quality and the reliability of PCB.

Description of drawings

Fig. 1 is the side-looking structural representation of a kind of multilayer board in the prior art;

Fig. 2 is the plan structure schematic diagram of multilayer board in the prior art;

Fig. 3 is the partial side TV structure schematic diagram of multilayer board shown in Figure 2;

Fig. 4 is the partial side TV structure schematic diagram of the printed circuit board (PCB) that the embodiment of the invention provided;

Fig. 5 is the plan structure schematic diagram one of internal layer signals layer in the printed circuit board (PCB) shown in Figure 4;

Fig. 6 is the plan structure schematic diagram two of internal layer signals layer in the printed circuit board (PCB) shown in Figure 4;

Fig. 7 is the plan structure schematic diagram three of internal layer signals layer in the printed circuit board (PCB) shown in Figure 4.

Embodiment

Also in conjunction with the accompanying drawings the present invention is described in further detail below by specific embodiment.

Fig. 4 is the partial side TV structure schematic diagram of the printed circuit board (PCB) that the embodiment of the invention provided, and Fig. 5 is the plan structure schematic diagram one of internal layer signals layer in the printed circuit board (PCB) shown in Figure 4.This PCB is specially the multilayer PDB with multilayer signal layer, and it comprises that internal layer signals layer 1 can be formed by the copper sheet of one or more copper cladding plates by dielectric layer 20 isolated internal layer signals layer 1 and outer signals layers 2.As shown in Figure 5, internal layer signals layer 1 comprises holding wire zone 3 and holding wire zone 3 white space 4 in addition that is provided with the holding wire pattern.Be provided with balance weight 5 in the white space 4, balance weight 5 is used for supporting in the pressing process of PCB the dielectric layer 20 of internal layer signals layer 1 both sides.

Adopt the technical scheme of present embodiment, the sudden change of each layer thickness of PCB is reduced, thereby stressed more even in the pressing process reduces even avoid the phenomenon of local warpage deformation to take place.

Preferably balance weight equates with the thickness of holding wire pattern, for dielectric layer provides the support force consistent with holding wire.Further, balance weight preferably adopts and holding wire pattern identical materials, i.e. etching formation on same copper sheet in same etch step, thus guarantee consistency of thickness, and needn't increase operation and material cost.

In the present embodiment, a plurality of balance weights 5 are set preferably, and each balance weight 5 evenly and the compartment of terrain be distributed in the white space 4, the shape of cross section of balance weight 5 be a circle, as shown in Figure 5.In the practical application, the shape of cross section of balance weight 5 also can be for quadrangle, square, triangle etc., shown in Fig. 6 and 7.Distance between each balance weight 5 preferably approximates the width of balance weight 5.

For avoiding the influence of balance weight to existing holding wire pattern, the pattern of balance weight should and the holding wire pattern between keep certain distance.Make in the regulation at existing PCB, have the safe distance that requires between the holding wire pattern, for example 0.5 millimeter (mm), the distance between balance weight and the holding wire pattern is preferably greater than safe distance, and particularly preferably be about safe distance twice.

Adopt the technical scheme of present embodiment, the balance weight of increase can be and the copper billet of holding wire same material, can be described as balance copper point or static copper point again.Be not connected conducting between balance weight and other holding wires, do not have the signal transmission.Being provided with of balance weight can make the abrupt changes in thickness of signals layer reduce, for the dielectric layer of internal layer signals layer both sides provides support, the support force that the dielectric layers such as base material of prepreg, copper-clad plate are subjected in the pressing process is more even, reduce even avoid the generation of warpage deformation, the balance and stability of the PCB after the pressing have been guaranteed, improve end product quality and the reliability of PCB, and then saved product cost effectively.

The PCB structural design of present embodiment is easy to realize in the software design procedure of existing PCB, for example adopts " Allegro software " commonly used now, when finishing wires design, increases the laying of balance weight at white space.Laying zone, the spacing that balance weight and holding wire pattern are set that can be by selecting balance weight, the shape that the spacing between the balance weight is set and balance weight is set are finished layout-design.The improvement of such scheme in actual design is little, simple to operate, so feasibility is strong, and design and production cost are low.

Balance weight among the PCB of the present invention is not limited to polylith evenly is provided with at interval, can also be for being arranged on the monoblock pattern in the white space.When the pattern of design balance piece, need avoid the balance weight may be to the short circuit of holding wire influence, the influence that electronic component is provided with etc., again in conjunction with the requirement of software design procedure convenience, the scheme of the foregoing description is for preferred embodiment.

PCB of the present invention is not limited to the multi-layer PCB that formed by the polylith copper-clad plate, goes for all and has the internal layer signals layer that is clipped in the dielectric layer, and need to carry out the PCB of stitching operation.Can make dielectric layer stressed evenly for dielectric layer provides support in the pressing process, avoid PCB local warping phenomenon to occur.

It should be noted that at last: above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the spirit and scope of various embodiments of the present invention technical scheme.

Claims

1, a kind of printed circuit board (PCB), comprise by isolated internal layer signals layer of dielectric layer and outer signals layer, described internal layer signals layer comprises holding wire zone and the holding wire zone white space in addition that is provided with the holding wire pattern, it is characterized in that: be provided with balance weight in the described white space, be used for supporting the dielectric layer of described internal layer signals layer both sides in the pressing process of described printed circuit board (PCB).

2, printed circuit board (PCB) according to claim 1 is characterized in that: described balance weight equates with the thickness of described holding wire pattern.

3, printed circuit board (PCB) according to claim 2 is characterized in that: described balance weight adopts and described holding wire pattern identical materials, and etching forms in same etch step.

4, according to claim 1 or 2 or 3 described printed circuit board (PCB)s, it is characterized in that: the distance between described balance weight and the described holding wire pattern is greater than safe distance.

5, printed circuit board (PCB) according to claim 4 is characterized in that: the distance between described balance weight and the described holding wire pattern be described safe distance twice.

6, according to claim 1 or 2 or 3 described printed circuit board (PCB)s, it is characterized in that: the quantity of described balance weight is a plurality of, and even and compartment of terrain is distributed in the described white space.

7, according to claim 1 or 2 or 3 described printed circuit board (PCB)s, it is characterized in that: the shape of cross section of described balance weight is circle, quadrangle or triangle.