阅读说明：本技术 一种改善印制电路板压合空洞的方法 (Method for improving press-fit cavity of printed circuit board ) 是由 乐禄安 孙保玉 任玉石 刘海洋 于 2019-09-20 设计创作，主要内容包括：本发明提供了一种改善印制电路板压合空洞的方法,包括如下步骤：开料得到内层芯板,通过内层图形和蚀刻处理,在内层芯板上制作内层线路,并在内层芯板中内层线路以外的无铜区处均间隔交错设置若干个铜PAD,制得内层板；通过半固化片将内层板和外层铜箔压合为一体,制得多层板；依次对多层板进行后工序处理制得印制电路板。本发明通过在内层芯板上的无铜区处设置铜PAD形成假铜区域,从而提高了内层芯板上的残铜率来达到平衡压力的目的,并保证无铜区处的流胶充分,避免出现层压空洞的问题。(The invention provides a method for improving a press-fit cavity of a printed circuit board, which comprises the following steps: cutting to obtain an inner core board, manufacturing an inner circuit on the inner core board through inner pattern and etching treatment, and alternately arranging a plurality of copper PADs at copper-free areas except the inner circuit in the inner core board at intervals to obtain an inner layer board; pressing the inner layer board and the outer layer copper foil into a whole through a prepreg to obtain a multilayer board; and sequentially carrying out post-process treatment on the multilayer board to obtain the printed circuit board. According to the invention, the copper PAD is arranged at the copper-free area on the inner core board to form the false copper area, so that the residual copper rate on the inner core board is improved to achieve the purpose of pressure balance, the full glue flowing at the copper-free area is ensured, and the problem of lamination cavities is avoided.)

1. A method for improving a press fit cavity of a printed circuit board is characterized by comprising the following steps:

s1, cutting to obtain an inner core board, manufacturing an inner circuit on the inner core board through inner pattern and etching treatment, and alternately arranging a plurality of copper PADs at copper-free areas except the inner circuit in the inner core board to obtain an inner layer board;

s2, pressing the inner layer board and the outer layer copper foil into a whole through a prepreg to obtain a multilayer board;

and S3, sequentially carrying out outer layer drilling, copper deposition, full-board electroplating, outer layer circuit manufacturing, solder mask manufacturing, surface treatment and forming on the multilayer board to obtain the printed circuit board.

2. The method of claim 1, wherein in step S1, the copper PAD has the same shape and size, and is circular, oval, diamond or square.

3. The method of claim 1, wherein the distance between the copper PAD and the nearest inner layer circuit or drilling position is greater than or equal to 1.5 mm.

4. The method of claim 1, wherein in step S1, the area of the inner layer of the core board is larger than 4mm and is outside the inner layer of the circuit board²The copper-free areas are all provided with a plurality of copper PADs in a staggered mode at intervals.

5. The method of claim 1, wherein the copper PADs are spaced apart at regular intervals, and the distance between adjacent copper PADs is the size of the copper PADs.

6. The method of claim 5, wherein when the copper PADs are arranged in a plurality of rows, the copper PADs of adjacent rows are staggered such that each copper PAD of a rear row corresponds to a gap between adjacent copper PADs of a front row.

Technical Field

The invention relates to the technical field of circuit board manufacturing, in particular to a method for improving a press fit cavity of a printed circuit board.

Background

Lamination voids are a common defect in PCB (printed circuit board) processing; the cavity of the resin can greatly reduce the voltage resistance of a PCB product, even can cause short circuit and seriously affect the reliability of the product; the reason for generating the lamination cavity is that a larger open area (i.e. a copper-free area) exists after the inner layer circuit is manufactured on the inner layer core board, and due to the reason of large pressing pressure, the amount of the PP glue is easy to run off through the open areas, and the problem of the lamination cavity at the open area is caused by uneven glue flowing. In order to solve the problem of lamination void of the printed circuit board, the lamination is generally improved by optimizing lamination parameters and changing prepregs with higher RC content in the industry at present.

However, the above solution has the following disadvantages: the optimization of pressing parameters is to increase the pressure of a press, and when the pressure is too high, layer deviation is easily caused to cause short circuit; and the production cost can be greatly improved by changing the prepreg with higher RC content.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a method for improving the lamination cavity of a printed circuit board.

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

The invention provides a method for improving a press-fit cavity of a printed circuit board, which comprises the following steps:

s1, cutting to obtain an inner core board, manufacturing an inner circuit on the inner core board through inner pattern and etching treatment, and alternately arranging a plurality of copper PADs at copper-free areas except the inner circuit in the inner core board to obtain an inner layer board;

s2, pressing the inner layer board and the outer layer copper foil into a whole through a prepreg to obtain a multilayer board;

and S3, sequentially carrying out outer layer drilling, copper deposition, full-board electroplating, outer layer circuit manufacturing, solder mask manufacturing, surface treatment and forming on the multilayer board to obtain the printed circuit board.

Further, in step S1, the copper PAD has the same shape and size, and is all circular, oval, diamond or square.

Further, the distance between the copper PAD and the nearest inner layer circuit or drilling position is more than or equal to 1.5 mm.

Further, in step S1, the area of the inner core board is larger than 4mm and is outside the inner layer circuit²The copper-free areas are all provided with a plurality of copper PADs in a staggered mode at intervals.

Further, copper PAD is equidistance interval arrangement setting, and adjacent copper PAD's distance is copper PAD's size of a dimension.

Furthermore, when the copper PADs are arranged in multiple rows, the copper PADs in adjacent rows are staggered, so that each copper PAD in the rear row corresponds to a gap between the adjacent copper PADs in the front row.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, the plurality of copper PADs are arranged at the copper-free area on the inner core plate at intervals in a staggered manner to form the false copper area, the gaps among the copper PADs ensure normal ventilation during pressing, and the copper PADs play roles in effectively blocking glue filling flowing and reducing outward loss of glue flowing of the copper-free area, so that the glue flowing can be retained in the empty area to properly increase the plate thickness, the residual copper rate on the inner core plate is improved, the purpose of pressure balancing is achieved, the glue flowing at the copper-free area is ensured to be sufficient, and the problem of lamination cavities is avoided; and the distance between the copper PAD and the nearest inner layer circuit or drilling position is controlled to be more than or equal to 1.5mm, so that the quality problems of short circuit, poor electrical property and the like caused by the influence of pressing and later processes of the printed circuit board can be effectively avoided.

Detailed Description

In order to more fully understand the technical contents of the present invention, the technical solutions of the present invention will be further described and illustrated with reference to the following specific embodiments.