阅读说明：本技术 一种内埋电容的线路板及其制作方法 (Circuit board with embedded capacitor and manufacturing method thereof ) 是由 方磊 王健 孙彬 沈洪 李晓华 于 2019-11-06 设计创作，主要内容包括：本发明涉及一种内埋电容的线路板及其制作方法,属于线路板制作技术领域。包括步骤：湿膜涂布/干膜层压,曝光,显影,线路蚀刻,退膜,表面处理,印刷,烘烤。本发明的有益效果是：通过蚀刻方法,在制作线路的同时将电容器极板一起制作出来,并且在印刷时,选择高介电常数的油墨进行印刷,线路板的制作过程中直接形成电容器,无需另外单独制作电容器,工艺简单,且能够大幅度降低成本。电容器直接形成于线路板上,工艺简单,且无需进行精确对位装配,降低成本。无需其他材料封装,体积减小。改变平行线路长度即可轻易改变电容器极板面积,从而制作不同电容值的电容器。对绝缘基材的材质无要求,可适用于所有基材。(The invention relates to a circuit board with a built-in capacitor and a manufacturing method thereof, and belongs to the technical field of circuit board manufacturing. The method comprises the following steps: wet film coating/dry film lamination, exposure, development, circuit etching, film stripping, surface treatment, printing and baking. The invention has the beneficial effects that: the capacitor plates are manufactured together while the circuit is manufactured through an etching method, and in the printing process, the printing ink with high dielectric constant is selected for printing, so that the capacitor is directly formed in the manufacturing process of the circuit board, the capacitor does not need to be manufactured separately, the process is simple, and the cost can be greatly reduced. The capacitor is directly formed on the circuit board, the process is simple, accurate alignment assembly is not needed, and the cost is reduced. And the volume is reduced without other material encapsulation. The area of the capacitor plate can be easily changed by changing the length of the parallel line, thereby manufacturing capacitors with different capacitance values. The material of the insulating base material has no requirement, and the insulating base material is suitable for all base materials.)

1. A method for manufacturing a circuit board with a built-in capacitor is characterized by comprising the following steps: wet film coating/dry film lamination, exposure, development, circuit etching, film stripping, surface treatment, printing and baking.

2. The method for manufacturing a circuit board with a built-in capacitor according to claim 1, comprising the following steps:

step A: coating a wet film/laminating a dry film on the surface of the copper foil of the circuit board;

and B: exposing and developing to form a protection layer of a common circuit pattern and a parallel circuit of a capacitor plate;

and C: removing the copper foil without the protective layer by etching, and leaving the required parallel circuit (1) of the common copper circuit and the capacitor plate;

step D: removing the film, and removing the surface protection layer to obtain a parallel line (1) of the required common line and the capacitor plate;

step E: carrying out tin surface treatment, and forming a metal protective layer (2) on the outer layer of the parallel line (1) of the common line and the capacitor plate to protect the parallel line (1) of the common line and the capacitor plate from being oxidized and corroded;

step F: printing ink (3) as a medium on the circuit board except the welding area and baking for curing.

3. The method for manufacturing a circuit board with a built-in capacitor according to claim 1, wherein: the ink (3) is an ink with high dielectric constant.

4. The method for manufacturing a circuit board with a built-in capacitor according to claim 1, wherein: the side surface of the parallel line (1) is a plate surface of a capacitor, and the length of the parallel line (1) is changed, namely the plate area of the capacitor is changed, so that the capacitors with different capacitance values are obtained.

5. The method for manufacturing a circuit board with a built-in capacitor according to claim 1, wherein: the parallel lines (1) are positioned on the same surface of the insulating base material (4).

6. The method for manufacturing a circuit board with a built-in capacitor according to claim 1, wherein: the parallel lines (1) are linear or nonlinear.

7. The utility model provides a circuit board of embedded capacitor which characterized in that: the method of any one of claims 1 to 6.

Technical Field

The invention relates to a circuit board with a built-in capacitor and a manufacturing method thereof, and belongs to the technical field of circuit board manufacturing.

Background

In recent years, with the progress of miniaturization of electronic devices, the size of a wiring board package is also required to be miniaturized. To meet this demand, not only the size of the wiring board itself but also the size of the electronic components on the wiring board are reduced.

The capacitor is one of the electronic components used in electronic devices in large quantity, and the basic principle of the capacitor is charging and discharging, and alternating current and direct current blocking. According to the principle, the capacitor has a plurality of purposes, such as coupling, bypass, filtering, tuning loop, energy conversion, control and the like, and the capacitor is configured in a default way during the operation of the circuit board. The simplest capacitor, from a capacitor's structural point of view, is made up of plates at both ends and an insulating dielectric (including air) in the middle. When energized, the plates become charged, creating a voltage (potential difference), but the entire capacitor is non-conductive due to the intervening insulating material.

Two polar plates of the traditional capacitor need to be overlapped or wound in a staggered mode, then pins are led out, and the manufacturing is troublesome. After the working part of the traditional capacitor is manufactured, other materials are required to be added for packaging so as to protect the capacitor, and the volume of the capacitor is increased. The traditional single capacitor is assembled on a circuit board after accurate alignment after being manufactured, and the process is complex. The traditional embedded capacitor can only be used for double-sided boards and multi-sided boards and cannot be used for single-sided boards. To obtain a capacitor with a large capacitance value, a dielectric with a high dielectric constant is required, and the traditional embedded capacitor is formed by an intermediate insulating substrate, so that the requirement on the intermediate insulating substrate is high, and the realization is difficult. To obtain a capacitor with a large capacitance value, the distance between two plates needs to be very close, i.e. the intermediate insulating substrate needs to be very thin, the cost is high, and the processing difficulty is high.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides the circuit board with the embedded capacitor and the manufacturing method thereof.

The invention is realized by the following technical scheme: a method for manufacturing a circuit board with a built-in capacitor is characterized by comprising the following steps: wet film coating/dry film lamination, exposure, development, circuit etching, film stripping, surface treatment, printing and baking.

The method specifically comprises the following steps:

step A: coating a wet film/laminating a dry film on the surface of the copper foil of the circuit board;

and B: exposing and developing to form a protection layer of a common circuit pattern and a parallel circuit of a capacitor plate;

and C: removing the copper foil without the protective layer by etching, and leaving the required parallel circuit of the common copper circuit and the capacitor plate;

step D: removing the film, and removing the surface protection layer to obtain a parallel line of the required common line and the capacitor plate;

step E: carrying out tin surface treatment, and forming a metal protective layer outside parallel lines of a common line and a capacitor plate to protect the common line and the parallel lines of the capacitor plate from oxidation and corrosion;

step F: printing ink as medium on the circuit board except the welding area and baking for curing.

The ink is high dielectric constant ink.

The side surface of the parallel line is the plate surface of the capacitor plate, and the change of the length of the parallel line changes the area of the capacitor plate, so that the capacitors with different capacitance values are obtained.

The parallel lines are positioned on the same surface of the insulating substrate.

The parallel lines are linear or nonlinear.

A circuit board with a built-in capacitor adopts the manufacturing method.

The invention has the beneficial effects that: the capacitor plates are manufactured together while the circuit is manufactured through an etching method, and in the printing process, the printing ink with high dielectric constant is selected for printing, so that the capacitor is directly formed in the manufacturing process of the circuit board, the capacitor does not need to be manufactured separately, the process is simple, and the cost can be greatly reduced. The capacitor is directly formed on the circuit board, the process is simple, accurate alignment and assembly are not needed, alignment and assembly equipment can be omitted, and the cost is reduced. The polar plate is formed by parallel lines, the medium is formed by filling ink, the capacitor is directly formed on the circuit board, other materials are not needed for packaging, the size is reduced, and the cost is reduced. The side of the parallel circuit is the plate surface of the capacitor plate, and the area of the capacitor plate can be easily changed by changing the length of the parallel circuit, so that the capacitors with different capacitance values can be manufactured. The two electrodes of the capacitor are formed by parallel lines on the same side of the insulating substrate, and the embedded capacitor can be used for a single panel. The line spacing is the polar plate spacing, and the existing line spacing can be very small, so that a capacitor with a large capacitance value can be easily obtained, and the requirement on the thickness of an insulating base material is avoided. The ink between two polar plates forms a dielectric medium, the dielectric constant of the ink determines the capacitance value of the capacitor, and the insulating substrate has no requirement on the material of the insulating substrate and can be suitable for all substrates.

Drawings

The invention is further illustrated below with reference to the figures and examples.

FIG. 1 is a schematic diagram of a capacitor formed in accordance with the present invention;

fig. 2 is a sectional view a-a of fig. 1.

In the figure: 1. parallel lines, 2, a metal protective layer, 3, ink, 4 and an insulating substrate.

Detailed Description

The method for manufacturing the circuit board with the embedded capacitor as shown in fig. 1 and fig. 2 is characterized by comprising the following steps: wet film coating/dry film lamination, exposure, development, circuit etching, film stripping, surface treatment, printing and baking.

The method specifically comprises the following steps:

step A: coating a wet film/laminating a dry film on the surface of the copper foil of the circuit board;

and B: exposing and developing to form a protection layer of a common circuit pattern and a parallel circuit of a capacitor plate;

and C: removing the copper foil without the protective layer by etching, and leaving the required parallel circuit 1 of the common copper circuit and the capacitor plate;

step D: removing the film, and removing the surface protective layer to obtain a parallel line 1 of the required common line and the capacitor plate;

step E: carrying out tin surface treatment, and forming a metal protective layer 2 on the outer layer of the parallel line 1 of the common line and the capacitor plate to protect the parallel line 1 of the common line and the capacitor plate from oxidation and corrosion;

step F: printing ink 3 as a medium on the circuit board except the welding area and baking for curing.

The ink 3 is high dielectric constant ink.

The side surface of the parallel line 1 is a plate surface of a capacitor, and the length of the parallel line 1 is changed, namely the area of a capacitor plate is changed, so that the capacitors with different capacitance values are obtained.

The parallel lines 1 are located on the same side of the insulating substrate 4.

The parallel lines 1 are linear or nonlinear.

A circuit board with a built-in capacitor adopts the manufacturing method.

The capacitor plate is composed of two parallel lines on the same surface of the insulating substrate 1; the insulating medium is composed of high dielectric constant ink 3; the side surfaces of the parallel lines are the plate surfaces of capacitor plates, and when the two parallel lines are electrified with different electricity, positive charges and negative charges are respectively gathered on the side surfaces of the two parallel lines close to each other; the line pitch is the plate pitch.

Wherein the capacitance formula is: （C: capacitance, ε: dielectric constant of the medium, S: plate area, k: electrostatic force constant, d: polar plate spacing)

In order to increase the capacitance, a dielectric having a high dielectric constant may be used, the plate area (line side area) may be increased, and the plate pitch (line pitch) may be decreased, wherein the plate area may be most easily increased, and the parallel lines forming the plate may be made zigzag, and the length of the plate parallel lines may be increased, thereby increasing the parallel line side area (plate area).

The method is suitable for the circuit board with the line distance of 3-500 mu m; the method is suitable for the circuit board with the copper thickness of 2-35 mu m; is suitable for the circuit board with the thickness of the insulating base material of 5-200 mu m.