KR20080092216A - Base substrate and pcb and the same manufacturing method - Google Patents

Abstract

A base substrate, a printed circuit board and an electronic device using the same are provided to prevent generation of a heating point by uniformly discharging heat generated from an electronic device. An electronic device has an electronic component(12), a conducting layer(16), an insulation layer(14), and a base substrate(18). The electronic component generates the heat. A pattern is formed on the conducting layer on which the electronic components are mounted. The insulation layer is formed on a lower part of the conducting layer. The base substrate is formed on a lower part of the insulation layer, and is composed of a graphite of 50 to 95weight% and a thermosetting resin of 5 to 50weight%. The graphite is the natural graphite. The thermosetting resin is one of an epoxy resin having a hardener, a fluoric resin and a phenol resin.

Description

BASE SUBSTRATE AND PCB AND THE SAME MANUFACTURING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base substrate, a printed circuit board (PCB), and an electronic device employing the same. In particular, the present invention effectively discharges heat by forming a mixture of graphite and a thermosetting resin. At the same time, the present invention relates to a heat-dissipating base substrate, a PC, and an electronic device employing the same, which is light and dust-free.

As the trend of the electronic industry has recently become lighter and shorter, the amount of heat generated per unit volume is increasing because electronic devices have to mount a large number of electronic components in a narrow space. In particular, in the case of a PCB that needs to be directly mounted with electronic components, development of a heat dissipation solution for effectively dissipating heat generated from the electronic components to the outside is urgently needed.

Therefore, the PCB uses the base substrate as a material with high thermal conductivity in order to discharge heat generated from electronic components more effectively.

As the base substrate material adopted in the PCB as described above, metal or ceramic is mainly used.

First, the base substrate made of metal is heavy because of its high specific gravity, and the heat transfer coefficient in each direction is the same, so the heat transfer in the thickness direction is excellent, but heat transfer in the plane direction is relatively smooth, which causes local hot spots. have. In order to solve this problem, a heat sink is installed on the base board, but due to the difference in the coefficient of thermal expansion of the heat sink and the base board, the contact surface floats, which hinders heat transfer.

In addition, in the case of a base substrate made of a ceramic, the specific gravity is large, such as a metal, heavy, ductility is well broken, there is a problem that the heat dissipation effect is lowered.

Therefore, in order to overcome this problem, a base substrate made of graphite has been developed. However, a new problem arises in that peeling phenomenon occurs on the surface due to weak bonding force only with graphite particles.

Accordingly, an object of the present invention is to provide a base substrate, a PCB, and an electronic device employing the same, which is devised to solve the above problems, and has excellent heat dissipation effect, thereby preventing hot spots from occurring.

Another object of the present invention is to provide a base substrate, a PC, and an electronic device employing the same, to prevent cracking due to increased ductility.

Another object of the present invention is to provide a base substrate, a PC, and an electronic device employing the same, to prevent foreign substances from occurring on a surface thereof.

In addition, an object of the present invention is to provide a light weight base substrate, PCB and an electronic device employing the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base substrate, a printed circuit board (PCB), and an electronic device employing the same. In particular, the present invention effectively discharges heat by forming a mixture of graphite and a thermosetting resin. At the same time, the present invention relates to a heat-dissipating base substrate, a PC, and an electronic device employing the same, which is light and dust-free.

Here, it is preferable that graphite is natural graphite, and spherical graphite is more preferable among natural graphite. In addition, the thermosetting resin is preferably one of a fluororesin, a phenol resin or an epoxy resin containing a curing agent.

Next, the PCB according to another aspect of the present invention is a conductive layer having a pattern so that the electronic component can be mounted, an insulating layer formed on the lower portion of the conductive layer and a lower portion of the insulating layer and 50 to 95 wt% graphite and thermosetting It includes a base substrate composed of 5 to 50% by weight of resin.

Here, it is preferable that graphite is natural graphite, and spherical graphite is more preferable among natural graphite. In addition, the thermosetting resin is preferably one of a fluororesin, a phenol resin or an epoxy resin containing a curing agent.

In addition, the conductive layer is preferably one of a conductive film, paste, ink or lead wire, and the insulating layer preferably includes at least one or more of alumina or boron nitride.

Next, an electronic device according to another aspect of the present invention, an electronic component that generates heat, a conductive layer having a pattern so that the electronic component can be mounted, an insulating layer formed below the conductive layer, and the insulating layer The base substrate is formed at the bottom of the composition and composed of 50 to 95% by weight of graphite and 5 to 50% by weight of the thermosetting resin.

Here, it is preferable that graphite is natural graphite, and spherical graphite is more preferable among natural graphite. In addition, the thermosetting resin is preferably one of a fluororesin, a phenol resin or an epoxy resin containing a curing agent.

In addition, the conductive layer is preferably one of a conductive film, paste, ink or lead wire, and the insulating layer preferably contains at least one or more of alumina or boron nitride.

As described above, since the base substrate, the PCB, and the electronic device employing the same have a base substrate including graphite powder having a larger anisotropy than a metal, heat generated in the electronic component is uniformly discharged to the outside. Hot spots are prevented from occurring.

In addition, since the base substrate, the PCB, and the electronic device employing the same according to the present invention include a base substrate including a thermosetting resin, ductility is increased, thereby preventing the base substrate from being broken.

In addition, since the base substrate, the PCB, and the electronic device employing the same according to the present invention include a base substrate including a thermosetting resin, foreign substances may be prevented from occurring on the surface of the base substrate.

In addition, since the base substrate, the PCB, and the electronic device employing the same according to the present invention have a base substrate made of graphite powder and a thermosetting resin having a smaller specific gravity than metals or ceramics, the overall weight can be significantly reduced.

Hereinafter, an embodiment of a base substrate, a PCB, and an electronic device employing the same according to the present invention will be described with reference to the accompanying drawings.

1 is a diagram of an electronic device provided with a base substrate and a PCB according to an embodiment of the present invention.

First, the electronic device 100 includes an electronic component 12 that generates heat, a conductive layer 14 having a pattern formed thereon so that the electronic component 12 can be mounted, and an insulating layer formed under the conductive layer 14. And a base substrate 18 formed under the insulating layer 16.

The electronic component 12 may be an LED, a central processing unit (CPU), a memory, a resistor, a capacitor, an inductor, an integrated circuit (IC), and the like, which may be mounted on the PCB 10. The electronic component 12 generates heat by electricity applied during operation.

The conductive layer 14 is positioned under the electronic component 12, and a pattern is formed to mount the electronic component 12. The pattern may be formed by printing a conductive paste for baking on a silk screen, baking the plate, and plating the surface thereof, or may be formed by exposing the pattern and etching the exposed pattern. Since the method of forming the pattern is well known to those skilled in the art, a detailed description thereof will be omitted.

The insulating layer 16 is formed under the conductive layer 14 to electrically shield the conductive layer 14 and the outside. As the insulating layer 16, a ceramic having excellent electrical insulation is mainly used.

The base substrate 18 is formed under the insulating layer 16 to impart durability of the PCB 10 and discharge heat transferred from the electronic component to the insulating layer to the outside. Base substrate 18 according to the characteristics of the present invention is composed of 50 to 95% by weight of graphite and 5 to 50% by weight of thermosetting resin. In general, when the sheet is formed by compressing natural graphite, the formed sheet has a greater thermal conductivity in the plane direction than the thickness direction, thereby preventing hot spots from being generated by dissipating heat to the outside more uniformly than metal. Such natural graphite may be any type of natural graphite, but it is preferable to adopt spherical graphite having a uniform density and low generation of voids when forming sheets due to uniform particle sizes. The spherical graphite is graphite obtained by spheroidizing wide and thin plate-like graphite into round particles. In addition, expanded graphite may be used instead of natural graphite.

In addition, the thermosetting resin is preferably one of an epoxy resin containing a fluororesin, a phenol resin or a curing agent. The resins are thermosetting resins, which are resistant to heat, and are thus installed at locations where heat is generated.

When the composition ratio of the spherical graphite and the thermosetting resin is high (ie, 5 wt% or less of the thermosetting resin), the moldability and mechanical strength cannot be secured, and the composition ratio of the thermosetting resin is high (that is, the thermosetting resin 50% by weight or more), the electrical conductivity is lowered, so the base substrate according to the present invention includes 50 to 95% by weight of graphite and 5 to 50% by weight of the thermosetting resin.

The method of preparing a sheet by mixing the thermosetting resin and spherical graphite is compression molded at a pressure of 1.0 to 5.0 kgf per cm 2. In addition, it is a matter of course that a roll blow molding may be performed by using a calender in which the powder mixed with the thermosetting resin and graphite is heated.

The base substrate 18 manufactured as described above has an electrical conductivity of 100 S / cm or more, a flexural strength of 9 to 35 MPa, and an elastic modulus of 1000 to 7000. In addition, the base substrate 18 is provided with ductility so that yield occurs when the strain behavior with respect to stress occurs.

Hereinafter, the manufacturing method of the base substrate according to the embodiment of the present invention in detail.

First, the pulverization of the spherical graphite powder uses vibration or ultrasonic waves to enable uniform mixing in the step of mixing with the thermosetting resin powder to be described later.

Next, since the spherical graphite powder and the thermosetting resin powder have a low apparent density, a phenol resin powder prepared to contain a curing agent in the case of phenol resin for the uniform mixing or a powder in the case of epoxy resin is used. Mix with and use. At this time, through the classification process, the thermosetting resin is used so that the average particle size is 5 to 100 ㎛. In this case, the average particle size of the thermosetting resin is 5 μm or less, so that it is difficult to uniformly mix with the spherical graphite powder, and in the case of 100 μm or more, it is difficult to uniformly coat the surface of the spherical graphite powder. Therefore, it is necessary to keep it within the range of 5 μm to 100 μm.

When the spherical graphite powder and the thermosetting resin powder are mixed, the rotation speed of the rotary blade is preferably 500 to 16,000 rpm, preferably 500 to 10,000 rpm. Here, the rotary blades can be all of the "V-shaped", "U-shaped", "--shaped", of course, two or more rotary blades can also be a composite rotary blade. Here, the rotation speed of the rotary blade is difficult to uniformly mix at 500rpm or less, and at 10,000rpm or more, the spherical graphite powder itself is destroyed to lose the characteristics of graphite. Therefore, when the spherical graphite powder and the thermosetting resin powder of the present invention are mixed, the rotation speed of the rotary blade is preferably 500 to 10,000 rpm. At this time, the dry mixer used is preferably a super mixer, Henschel mixer, zero gravity mixer and the like.

The powder mixed above was compression molded into a mold having a desired area at room temperature to prepare a base substrate 18. At this time, the molding pressure is 1.0 to 5.0 kgf per cm 2. In addition, the molded base substrate is cured, wherein the curing temperature is 100 to 200 ° C. and the curing time is 10 to 100 minutes.

Next, the insulating layer 16 is formed on the base substrate 18. At this time, the ceramic layer is applied or the ceramic film is placed and then pressed to form the insulating layer 16. The insulating layer is a ceramic insulating layer made of alumina or boron nitride, and may be manufactured using one or more of these.

Next, a method of forming a pattern on the conductive layer 14 on the insulating layer 16 is performed by silkscreen printing a conductive paste for low temperature firing, which can be electrically conductive to form a circuit, and then surface-plated after firing. And a method of stacking a conductive thin film on top of the insulating layer, exposing the pattern, and etching the exposed pattern with a chemical to form a pattern as necessary.

An embodiment of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

1 is a diagram of an electronic device having a base substrate and a PCB installed in accordance with an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: electronic device 10: PCB

12: electronic component 14: insulating layer

16: conductive layer 18: base substrate

Claims (16)

In the base board for PCB, The base substrate is a PCB base substrate comprising 50 to 95% by weight of graphite and 5 to 50% by weight of the thermosetting resin. The method of claim 1, The base substrate for a PCB, characterized in that the graphite is natural graphite. The method of claim 2, The natural graphite is a base substrate for a PCB, characterized in that the spherical graphite. The method of claim 1, The thermosetting resin is a base substrate for a PCB, characterized in that one of the epoxy resin containing a fluorine resin or a phenol resin or a curing agent. A conductive substrate having a pattern formed thereon for mounting electronic components, an insulating layer formed under the conductive layer, a base substrate formed under the insulating layer and composed of 50 to 95 wt% graphite and 5 to 50 wt% thermosetting resin PCB comprising a. The method of claim 5, PCB characterized in that the graphite is natural graphite. The method of claim 6, The natural graphite is a PCB characterized in that the spheroidal graphite. The method of claim 5, The thermosetting resin is a PCB, characterized in that one of the epoxy resin containing a fluororesin or a phenol resin or a curing agent. The method of claim 5, The conductive layer is a PCB, characterized in that one of the conductive film, paste, ink or lead wire. The method of claim 5, The insulating layer is a PCB characterized in that the ceramic layer to which a thermally conductive filler containing at least one or more of alumina or boron nitride (Boron Nitride) is added. An electronic component that generates heat, a conductive layer having a pattern formed thereon so that the electronic component can be mounted, an insulating layer formed under the conductive layer, and 50 to 95 wt% graphite formed under the insulating layer and a thermosetting resin 5 An electronic device comprising a base substrate composed of about 50% by weight. The method of claim 11, The graphite is an electronic device, characterized in that the natural graphite. The method of claim 12, The natural graphite is an electronic device, characterized in that the spherical graphite. The method of claim 11, The thermosetting resin is an electronic device, characterized in that one of the epoxy resin containing a fluorine resin, a phenol resin or a curing agent. The method of claim 11, The conductive layer is an electronic device, characterized in that one of the conductive film, paste, ink or lead wire. The method of claim 11, The insulating layer is an electronic device, characterized in that the ceramic layer to which the thermally conductive filler containing at least one or more of alumina or boron nitride (Boron Nitride) is added.

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