CN105636347A

CN105636347A - Structure design method for improving reliability of printed circuit board

Info

Publication number: CN105636347A
Application number: CN201410581607.3A
Authority: CN
Inventors: 杨际荣
Original assignee: ZHENJIANG HUAYANG INFORMATION TECHNOLOGY CO LTD
Current assignee: ZHENJIANG HUAYANG INFORMATION TECHNOLOGY CO LTD
Priority date: 2014-10-28
Filing date: 2014-10-28
Publication date: 2016-06-01

Abstract

The invention relates to a structure design method for improving the reliability of a printed circuit board. The method comprises the steps of forming a welding inner through hole by means of a perforating hole, hole insertion resin and a plating copper layer. The plating copper layer is composed of a wrapped copper layer and a terminated copper layer. The hole insertion resin is filled inside the perforating hole of the wrapped copper layer. The surface of the hole insertion resin is lower than the surface of the wrapped copper layer on the surface of the printed circuit board. The surface of the printed circuit board is provided with cylindrical recesses. The terminated copper layer is covered inside the surface of the printed circuit board and the above recesses so as to form a U shape to connect the hole insertion resin with the wrapped copper layer.

Description

A kind of construction design method improving printed circuit board (PCB) reliability

Technical field

The present invention relates to the structural design of printed circuit board (PCB), particularly to containing the printed circuit board arrangement of perforation in weld pad.

Background technology

Development along with electronic information technology, electronic product develops towards lightweight, microminiaturization, high speed direction, printed circuit board (PCB) is had higher requirement, also thus derive the printed circuit board arrangement of different form in the past, as containing through-hole construction in weld pad (Viaonpad) etc. (see figure 4).

What Fig. 4 showed is exactly perforation design in existing weld pad, and wherein 1 is end layers of copper, is generally Copper Foil direct pressing and obtains to dielectric layer 5; 2 is parcel layers of copper (wrappingplating), and this layers of copper plays the effect that through hole hole wall and aperture are wrapped up; 3 is end-blocking layers of copper (cappingplating), this layers of copper is connected with parcel layers of copper, also the through hole two ends being packed with plug socket resin 4 are closed with layers of copper simultaneously, electronic component so just can be installed on this through hole, therefore in weld pad, perforation design can save wiring space, improves wiring density.

In the weld pad of upper figure, through-hole construction there is also some problems. During as the through hole being plugged with resin carries out electro-coppering end-blocking, layers of copper is deposited on resin surface, and end-blocking layers of copper contacts in a planar manner with plug socket resin. It is that 0.2mm calculates according to the through hole diameter typically requiring consent, the contact area of layers of copper and resin only has 0.03 square millimeter, although the corrosion of plug socket resin can be improved the layers of copper adhesive force to resin by alkalinity potassium permanganate before copper facing to a certain extent, but so little contact area, and end-blocking layers of copper and resin plane the way of contact still can give printed circuit board (PCB) reliability bring hidden danger. Actually when printed circuit board (PCB) being carried out reliability test, it has been found that being easiest to produced problem is exactly crack occur between perforation aperture parcel layers of copper and end-blocking layers of copper in weld pad. Accordingly, it would be desirable to the carrying out of through-hole construction redesigns in weld pad, to improve the reliability of this type of printed circuit board (PCB).

Summary of the invention

Therefore, it is necessary to a kind of method designing printed circuit board (PCB) reliability that can improve and have perforation in weld pad, the method can solve to wrap up the problem easily producing crack between layers of copper and end-blocking layers of copper in existing weld pad in through-hole construction.

The structural design of a kind of printed circuit board (PCB) reliability that can improve and have perforation in weld pad is described below by design drawing:

In weld pad, perforation is made up of through hole, plug socket resin, copper electroplating layer. Wherein, copper electroplating layer is constituted with end-blocking layers of copper by wrapping up layers of copper, and plug socket resin is clogged in the through hole being coated with parcel layers of copper; The apparent height of plug socket resin wraps up the height of layers of copper lower than printed circuit board surface, forms cylindric defect in printed circuit board surface; End-blocking layers of copper covers in printed circuit board surface and aforesaid depression, forms one ' recessed ' font and connects plug socket resin and parcel layers of copper.

Compared with prior art, the method is by making to be formed between end-blocking layers of copper and through hole resin and parcel layers of copper the connected mode of three-dimensional ' recessed ' font, increase the contact area of end-blocking layers of copper, and then improve the adhesive force terminating layers of copper, such that it is able to improve containing the printed circuit board (PCB) reliability of through-hole construction in weld pad.

Accompanying drawing explanation

Fig. 1 is the structural representation of the substrate that design provides.

Fig. 2 is through-hole construction schematic diagram in the weld pad that in Fig. 1, substrate processing and fabricating is formed.

Fig. 3 is the close-up schematic view of through-hole construction in weld pad in Fig. 2.

Fig. 4 is perforation design diagram in existing weld pad.

As it is shown in figure 1, in the present embodiment, substrate 100 is need in print circuit plates making process to carry out the semi-finished product that boring makes, including layers of copper 110, insulating barrier 120. Layers of copper 110 can be cathode copper or calendering copper, and thickness can be 5 microns ~ 210 microns, the epoxy resin that insulating barrier 120 can strengthen for glass cloth, polyphenylene oxide, polyimides or politef etc., and thickness is 5 microns ~ 500 microns; Structure according to the circuit board to make can select the substrate 100 of different structure, it is possible to for single sided board, dual platen or multi-layer sheet. For the sake of simplicity, in the design, substrate 100 is dual platen.

As in figure 2 it is shown, 220 is parcel layers of copper, this layers of copper forms at inside through holes and printed circuit board surface deposition via plating mode, and the thick requirement according to final products of copper is generally 15 microns ~ 50 microns, and common is 20 microns ~ 30 microns; 230 is end-blocking layers of copper, and this layers of copper is also obtained by electroplating deposition copper, and copper thickness is not limit. 240 is the plug socket resin in through hole, and this resin requires, without solvent, to reach to solidify completely through overbaking after filling through hole.

Fig. 3 is the close-up schematic view of through-hole construction in weld pad in Fig. 2

From figure 3, it can be seen that the upper transverse plane of plug socket resin is lower than parcel layers of copper in through hole, define a columned depression in printed circuit board surface. Wherein, cylindrical height A is that on plug socket resin, transverse plane is to the distance on parcel layers of copper surface, and cylindrical diameter B is the aperture of through hole, and the ratio of general A and B is 2:1 ~ 0.1:1, it is preferable that the ratio of A and B is 1:1 ~ 0.5:1. End-blocking layers of copper 230 is when depositing to printed circuit board (PCB), not only can be deposited on the surface of circuit board, can also deposit in the columned depression that plug socket resin is formed in through hole, so, end-blocking layers of copper contacts with plug socket resin and parcel layers of copper simultaneously, forms the connected mode of a kind of ' recessed ' font.

Form the above structural design that can improve the printed circuit board (PCB) reliability with perforation in weld pad

Above, the structural design of perforation in the weld pad with high reliability is completed. The present invention by forming the connected mode of three-dimensional ' recessed ' font between end-blocking layers of copper and through hole resin, increase the contact area of end-blocking layers of copper and plug socket resin and parcel layers of copper, and then improve the adhesive force terminating layers of copper, thus reach to improve containing the printed circuit board (PCB) reliability of through-hole construction in weld pad.

It is understood that for the person of ordinary skill of the art, it is possible to conceive according to the technology of the present invention and make other various corresponding changes and deformation, and all these change and deform the protection domain that all should belong to the claims in the present invention.

Claims

1. the present invention relates to a kind of raising containing the structural design of the printed circuit board (PCB) reliability of perforation in weld pad, it includes herein below: in weld pad, perforation is made up of through hole, plug socket resin, copper electroplating layer;

Wherein, copper electroplating layer is constituted with end-blocking layers of copper by wrapping up layers of copper, and plug socket resin is clogged in the through hole being coated with parcel layers of copper; The apparent height of plug socket resin wraps up the height of layers of copper lower than printed circuit board surface, forms cylindric defect in printed circuit board surface; End-blocking layers of copper covers in printed circuit board surface and aforesaid depression, forms one ' recessed ' font and connects plug socket resin and parcel layers of copper.

2. improve containing the structural design of the printed circuit board (PCB) reliability of perforation in weld pad as claimed in claim 1, it is characterised in that in weld pad, perforation is made up of through hole, plug socket resin, copper electroplating layer.

3. improve containing the structural design of the printed circuit board (PCB) reliability of perforation in weld pad as claimed in claim 1, it is characterised in that in through hole, the apparent height of plug socket resin is lower than the apparent height of parcel layers of copper, forms cylindric defect in printed circuit board surface.

4. cylindric defect according to claim 3, it is characterised in that the ratio of cylindrical height and cylindrical diameter is 2:1 ~ 0.1:1; Preferably, the ratio of A and B is that after 1:1 ~ 0.5:1 subtracts copper, copper layer thickness is 5 microns ~ 10 microns.

5. cylindric defect according to claim 3, it is characterised in that the ratio of cylindrical height and cylindrical diameter is 1:1 ~ 0.5:1.

6. improve containing the structural design of the printed circuit board (PCB) reliability of perforation in weld pad as claimed in claim 1, it is characterised in that this printed circuit board (PCB) can be lamina, dual platen and multi-layer sheet.

7. improve containing the structural design of the printed circuit board (PCB) reliability of perforation in weld pad as claimed in claim 1, it is characterised in that this printed circuit board (PCB) can be hard circuit board, flexible circuit board and Rigid Flex.