KR20090083568A - Printed circuit board with embeded capacitor and fabricating method thereof - Google Patents

Abstract

A PCB with embedded capacitors and a manufacturing method thereof are provided to easily perform a capacitance value of low capacity by forming a first electrode and a second electrode in a side of a dielectric layer through a screen print method. A dielectric layer(110) is formed on a metal foil. Thickness of the metal foil is 1~100um. A first electrode(120) and a second electrode(130) are formed in both sides of the dielectric layer. Thickness of the dielectric layer is determined by thickness of a mask in screen printing. The first electrode and the second electrode are formed with thickness like the dielectric layer. A first electrode pad(125) is formed on a top part of the first electrode. A second electrode pad(135) is formed on a top part of the second electrode.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a printed circuit board having a built-in capacitor,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor-embedded printed circuit board and a manufacturing method thereof, and more particularly, to a capacitor-embedded printed circuit board and a method of manufacturing the same.

Printed Circuit Board (PCB) is a core component of a battery electronic product that connects various electronic components according to the circuit design of the electric wiring to the printed circuit board and supports the parts. It is used in household appliances, It is a passive component used in general.

A printed circuit board is obtained by attaching a thin plate of copper or the like to one side of a phenol resin or an epoxy resin insulating plate or the like and then etching the thin plate according to the wiring pattern of the circuit to form a necessary circuit, .

Such a printed circuit board is classified into a single-sided board, a double-sided board, and a multi-layer board according to the number of wiring circuit surfaces, and the higher the number of layers, the better the mounting force of components.

Meanwhile, due to the recent demand for miniaturization and high functionality of electronic products due to the development of the electronic industry, electronic components have become high density and high performance, and passive devices such as resistors, capacitors and inductors have been developed. Component) is also increasing relatively.

These passive components occupy more than 50% of the printed circuit board area. Therefore, reducing the volume occupied by the passive element is a way to miniaturize the electronic product.

Capacitors are used for coupling and decoupling, filters, impedance matching and signal matching, and charge pump in electronic circuits such as digital circuits, analog circuits, and high frequency circuits. And Demodulation, which are used for various purposes.

In recent years, various attempts have been made to integrate a capacitor in a printed circuit board due to the following factors.

1) With the miniaturization and complexity of electronic devices, the area where passive components can be mounted on a printed circuit board is reduced.

2) Parasitic impedance occurs due to various factors such as the conductor and solder between the passive element and the IC as the frequency of use by the speeding up of the electronic device becomes higher.

1 is a cross-sectional view of a conventional printed circuit board with a built-in capacitor.

A thin film dielectric layer 11 formed in the insulating layer 10; a lower electrode 12 formed under the thin dielectric layer 11; and an upper electrode 12 formed on the thin dielectric layer 11, And a lower electrode pad 14 formed on the insulating layer 10 and electrically connected to the lower electrode 12.

In the conventional capacitor-embedded printed circuit board thus configured, the thin dielectric layer 11, the lower electrode 12, and the upper electrode 13 are formed by a screen printing technique.

Since the thin dielectric layer 11 has a large area and a small thickness, it can be used as a high-capacity decoupling capacitor.

2A to 2D are cross-sectional views illustrating a conventional method of manufacturing a capacitor-embedded printed circuit board.

As shown, a thin dielectric layer 21 is first formed on the metal foil 20 by screen printing (FIG. 2A).

Next, a lower electrode 22 is formed by surrounding a part of the thin dielectric layer 21 on the metal foil 20 (FIG. 2B).

Next, an insulating layer 23 is laminated on the metal foil 20 so as to surround the thin dielectric layer 21 and the lower electrode 22 to form a laminated structure A (FIG. 2C).

After the stacked structure A is turned over, the metal foil 20 is etched to form the upper electrode 24 and the lower electrode pad 25 (FIG. 2D). At this time, the lower electrode 22 is electrically connected to the outside through the lower electrode pad 25.

In a conventional capacitor-embedded printed circuit board, it is important to control the thickness of a thin dielectric layer. In order to manufacture a capacitor of a high capacity, it is difficult to control the thickness because the area of mask opening is increased during screen printing. There is a problem.

Since the area of the mask to be masked during screen printing is increased to form a large area of the thin dielectric layer, the surface can not be formed flat and the surface roughness is generated. Which may cause problems in the contactability of the substrate.

In addition, the overlapping portion of the lower electrode and the upper electrode determines the capacitance of the capacitor. In forming the upper electrode, the lower electrode is hidden, and it is difficult to accurately control the overlapping area with the lower electrode.

In this case, forming a capacitor of a high capacity is not a serious problem, but it is difficult to manufacture a capacitor of a low capacity RF matching.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a capacitor-embedded printed circuit board and a method of manufacturing the capacitor-built-in printed circuit board, which can easily implement a designed capacitor capacitance value in manufacturing an embedded capacitor using a screen printing method.

A preferred embodiment of the capacitor-embedded printed circuit board of the present invention, which is designed to solve the above problems, includes a first electrode and a second electrode formed on both side surfaces of a dielectric layer, and a dielectric layer formed on each side of the dielectric layer, And a first electrode pad and a second electrode pad formed on the insulating layer, the first electrode pad and the second electrode pad being in contact with the first electrode and the second electrode, respectively.

Here, the dielectric layer is formed of a polymer / ceramic composite paste composed of an organic solvent, a ceramic powder having a high dielectric constant dispersed in the organic solvent, a polymer, and a curing agent.

The first electrode and the second electrode may be formed of a conductive paste.

A preferred embodiment of the method for manufacturing a capacitor embedded printed circuit board of the present invention comprises the steps of forming a dielectric layer on a metal foil and forming a first electrode and a second electrode on both sides of the dielectric layer above the metal foil Forming an insulating layer around each side of the dielectric layer, the first electrode, and the second electrode on the metal foil to form a laminated structure; and after the laminated structure is turned upside down, the metal foil is etched And forming a first electrode pad and a second electrode pad which are in contact with the first electrode and the second electrode and are spaced apart from each other.

Here, the dielectric layer, the first electrode, and the second electrode are formed by a screen printing method.

According to the present invention, since the first electrode and the second electrode are formed on the side surface of the dielectric layer in a screen printing manner, it is easy to control the overlapping area of the first electrode and the second electrode, The capacitance value of capacitance can be easily implemented, and thereby the capacitor for RF matching can be manufactured.

Hereinafter, the capacitor embedded printed circuit board of the present invention and the manufacturing method thereof will be described in detail with reference to FIGS. 3 to 5. FIG.

In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intention or custom of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

3A to 3D are cross-sectional views illustrating a method of manufacturing a capacitor-embedded printed circuit board of the present invention.

As shown, a dielectric layer 110 is first formed on the metal foil 100 (FIG. 3A).

Here, the metal foil 100 is made of any one material selected from among copper, copper-invar-copper, nickel, and nickel-coated copper. 100 mu m, and particularly preferably 10 mu m to 50 mu m.

The dielectric layer 110 is formed of a polymer / ceramic composite paste for a capacitor embedded printed circuit board and is formed on the metal foil 100 by a screen printing method.

The polymer / ceramic composite paste for a capacitor embedded printed circuit board comprises an organic solvent, a ceramic powder having a high dielectric constant dispersed in the organic solvent, a polymer, and a curing agent.

The ceramic powder has a particle diameter of 10 nm to 1000 nm. The ceramic powder may be at least one selected from the group consisting of BaTiO 3 (Barium Titanate), BST (Barium Strontium Titanate) and PZT (Plumbum Zirconate Titanate) Materials are used.

The polymer may be a thermosetting resin or a thermoplastic resin. However, considering the thermal stability, the polymer may be an epoxy, a polyimide, a polyacrylate, a polyethylene terephthalate (PET), or the like. It is preferable to use a thermosetting resin based on the same thermosetting resin and add thermoplastic resin if necessary.

As the curing agent, it is preferable to use a latent curing agent that does not harden at room temperature, such as DICY (Dicyandiamide) or imidazole coated with a polymer capsule.

Next, a first electrode 120 and a second electrode 130 are formed on both sides of the dielectric layer 110 on the metal foil 100 (FIG. 3B).

The first electrode 120 and the second electrode 130 are formed of a conductive paste and the conductive paste may include at least one selected from the group consisting of copper (Cu), silver (Ag), gold (Au), tin (Sn) A resin component such as epoxy or cellulose is added to a metal powder having high electrical conductivity such as nickel (Ni), and the mixture is kneaded with an organic solvent.

The first electrode 120 and the second electrode 130 are formed on both sides of the dielectric layer 110 by a screen printing method.

The thickness of the dielectric layer 110 is determined by the thickness of the mask itself during screen printing and is unaffected by the open area of the mask unlike the conventional technique.

That is, according to the present invention, when forming the dielectric layer 110, the open area of the mask does not affect the capacitor capacitance value, and the thickness of the dielectric layer 110 is determined only by the thickness of the mask , It is easy to control the thickness of the dielectric layer 110.

The first electrode 120 and the second electrode 130 are formed to have the same thickness as the dielectric layer 110.

According to the present invention, since the first electrode 120 and the second electrode 130 are formed on the side surface of the dielectric layer 110, the overlapped area of the first electrode 120 and the second electrode 130 can be controlled Therefore, it is possible to easily implement a capacitance capacity value of a low capacity designed in advance, and thereby, an RF matching capacitor can be manufactured.

An insulating layer 140 is formed to surround each side of the dielectric layer 110, the first electrode 120 and the second electrode 130 on the metal foil 100 to form a laminated structure B 3c).

The insulating layer 140 is preferably made of FR-4 epoxy pre-preg.

Next, after the stacked structure B is turned over, the metal foil 100 is etched to form first electrode pads 125 and second electrode pads 135 spaced from each other (FIG. 3D).

The first electrode 120 and the second electrode 130 are in contact with the first electrode pad 125 and the second electrode pad 135 and the first electrode pad 125 and the second electrode pad 130 135, respectively.

4 is a perspective view showing an embodiment of a capacitor-embedded printed circuit board of the present invention.

The first electrode 120 and the second electrode 130 are formed on both sides of the dielectric layer 110 and the first electrode pad 125 is formed on the first electrode 120 And a second electrode pad 135 is formed on the second electrode 130.

According to the present invention, a low capacitance capacitor of several tens pF can be realized, and FIG. 5 is a diagram showing a case of implementing a capacitor having a capacitance of 35 pF.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand.

Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by equivalents to the appended claims, as well as the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a conventional printed circuit board with a built-in capacitor; Fig.

FIGS. 2A to 2D are cross-sectional views illustrating a conventional method of manufacturing a capacitor-embedded printed circuit board. FIG.

3A to 3D are cross-sectional views illustrating a method of manufacturing a capacitor-embedded printed circuit board of the present invention.

4 is a perspective view showing an embodiment of a capacitor-embedded printed circuit board of the present invention.

5 illustrates a case of implementing a capacitor having a capacitance of 35 pF;

Description of the Related Art [0002]

100: metal foil 110: dielectric layer

120: first electrode 125: first electrode pad

130: second electrode 135: second electrode pad

Claims (8)

A first electrode and a second electrode formed on both sides of the dielectric layer; An insulating layer surrounding each side of the dielectric layer, the first electrode, and the second electrode; And And a first electrode pad and a second electrode pad formed on the insulating layer, the first electrode pad and the second electrode pad being in contact with the first electrode and the second electrode, respectively. The method according to claim 1, Wherein the dielectric layer comprises: A ceramic / ceramic composite paste composed of an organic solvent, a ceramic powder having a high dielectric constant dispersed in the organic solvent, a polymer, and a curing agent. 3. The method of claim 2, Wherein the ceramic powder is made of at least one material selected from the group consisting of BaTiO3 (Barium Titanate), BST (Barium Strontium Titanate), and PZT (Plumbum Zirconate Titanate). 3. The method of claim 2, Wherein the polymer comprises at least one material selected from the group consisting of epoxy, polyimide, polyacrylate, and polyethylene terephthalate (PET) as a main component. Board. The method according to claim 1, Wherein the first electrode and the second electrode are made of a conductive paste. Forming a dielectric layer on the metal foil; Forming a first electrode and a second electrode on both sides of the dielectric layer above the metal foil; Forming an insulating layer on each side of the dielectric layer, the first electrode, and the second electrode on the metal foil to form a laminated structure; And And forming a first electrode pad and a second electrode pad spaced apart from each other in contact with the first electrode and the second electrode by etching the metal foil after inverting the stacked structure, Gt; The method according to claim 6, Wherein the dielectric layer, the first electrode, and the second electrode are formed by a screen printing method. The method according to claim 6, Wherein the metal foil is made of any one material selected from the group consisting of copper, copper-invar-copper, nickel, and nickel-coated copper.

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