KR100939760B1 - Method for generating a substrate used for heat-radiating pcb and the substrate thereof - Google Patents

Abstract

PURPOSE: A method for manufacturing a substrate for a heat radiating printed circuit board and the substrate thereof are provided to improve insulation and heat dissipation by forming a middle layer between a heat sink layer and an electrical conductive layer. CONSTITUTION: A heat sink layer(210) is made of a metal board. A middle layer(220) includes a ceramic material with insulation and thermal conduction. The middle layer includes a ceramic layer(222), a correction layer(224), and an insulation layer(226). The ceramic layer is formed on the heat sink layer by a plasma spray coating method. The correction layer is filled in a surface crack of the ceramic layer. The insulation layer electrically insulates an electrical conductive layer(230) and the heat sink layer. The electric conductive layer is formed on the middle layer. The electric conductive layer includes the metal material with an electrical conduction.

Description

Method for producing a heat dissipation printed circuit board and its substrate {Method for generating a Substrate used for heat-radiating PCB and the Substrate}

1 is a view showing the structure of a conventional heat dissipation printed circuit board.

2 is a view showing a heat dissipation printed circuit board original plate 200 according to the present invention.

3 is a flowchart illustrating a method of manufacturing a heat dissipation printed circuit board original plate 200 according to the present invention.

4A to 4F are views showing a state of the original plate 200 formed in each manufacturing step of FIG. 3.

5 is a diagram illustrating a rolling process.

6 is a graph showing the effects of the present invention, which is a graph comparing the thermal conductivity of the original plate 200 with that of the conventional original plate 100.

The present invention relates to a method for manufacturing a heat dissipation printed circuit board and a disc, and more particularly, to a method for manufacturing a heat dissipation printed circuit board and a disc for improving heat dissipation and heat transfer characteristics by forming a ceramic layer without warping. It is about.

Recently, electronic devices have been integrated and miniaturized. One of the problems associated with the integration and miniaturization of electronic devices is the effective dissipation of the generated heat. This is because heat generation increases with integration, while heat generation space decreases with miniaturization. As a countermeasure, a heat-radiating printed circuit board having good heat dissipation characteristics is widely used.

In the conventional printed circuit board, the material of the original plate is synthetic resin, while the heat-dissipated printed circuit board increases the heat dissipation characteristics of the printed circuit board by replacing the supporting plate of the original plate with a metallic material and changing some structures. Increasing the heat dissipation characteristics of printed circuit boards is more necessary for high performance applications because of the better device characteristics due to the increased active area of the circuit elements.

1 is a view showing the structure of a conventional heat dissipation printed circuit board.

The conventional heat dissipation printed circuit board 100 includes a heat dissipation layer 101, an insulation layer 102, and an electrically conductive layer 403 in order from the bottom. The heat dissipation layer 101 is made of a metallic material having good heat dissipation characteristics and functions to dissipate heat generated from the electric conductive layer 103. Generally a metal plate is used. The insulating layer 102 electrically insulates the conductive layer 103 and the heat dissipating layer 101 and serves to closely adhere the two layers to each other, and is generally made of a thermosetting resin material. The conductive layer 103 is a layer connected to a device implemented on a heat dissipation printed circuit board and provides electrical conductivity to the device. The conductive layer 103 is made of a thin metallic material having good electrical conductivity and is generally patterned and implemented.

However, the original heat dissipation printed circuit board as shown in Figure 1 has the following disadvantages.

First, the heat dissipation characteristics are low. That is, as a result of selecting the synthetic resin material of the insulating layer to satisfy the insulating characteristics, it is not easy to increase the heat dissipation characteristics. The insulating layer 102 should simultaneously perform an insulation function and a heat transfer function (heat dissipation function) between the electrically conductive layer 103 and the heat dissipation layer 101. The heat-transfer layer 102 is an electric element 104 due to the characteristics of the material. The thermal conductivity of the material is too low to receive heat H from the heat transfer layer 101. This is because most synthetic resin materials are used.

Second, since the insulating property of the insulating layer is proportional to the thickness of the insulating layer and inversely proportional to the thickness of the heat dissipating layer, the other one must be sacrificed in order to increase either. If certain applications such as high efficiency LED lamps require high insulation and high heat dissipation at the same time, the conventional substrate of FIG. 1 is not suitable for application in this field. In general, the thickness of the insulating layer made of resin that satisfies the insulating properties required for the industry, such as LED, is 75 to 200 ㎛ thickness, the heat transfer properties that can be provided in this thickness is not enough to meet the standards required by the industry Do.

Third, there is a high risk of cracking of the conductive layer due to breakage of the insulating layer at high withstand voltage. The material of the insulating layer 102 is usually a general thermosetting resin and has a foam shape due to the properties of the material. In particular, when the withstand voltage generated by the circuit element increases according to the application field of the high heat generation high voltage such as the LED field and the LCD backlight field, the foam component peculiar to the thermosetting resin layer is blasted (exploded), and as a result, the electricity on the upper portion of the insulating layer 102 Causes cracks or cracks in the conductive layer 103. Cracking of the conductive layer 103 is a very serious problem because it causes the deterioration of the heat dissipation printed circuit board itself. In general, the withstand voltage of the conventional substrate 100 without generating a blasting phenomenon is 2 to 3 kv, which is not satisfactory to be applied to applications such as high efficiency LED.

Accordingly, the present invention has been made to solve the above problems, an object of the present invention is to increase the heat dissipation characteristics and to prevent the occurrence of blasting phenomenon by using a heat dissipation printed circuit board substrate that can be used in applications such as high efficiency LED To provide.

In order to solve the above problems, the present invention, in the method for manufacturing a heat dissipation printed circuit board disc used in the application field where the high heat dissipation high voltage electric element is used, (a) heat dissipation layer 210 by cutting the metal substrate Forming a; (b) forming an intermediate layer 220 including a ceramic material having insulation and thermal conduction on the heat dissipation layer 210; And (c) forming an electrically conductive layer 230 including a metallic material having electrical conductivity on top of the intermediate layer, wherein (b) forming the intermediate layer 220 includes (b1) the Forming a ceramic layer (222) including the ceramic material on the metal substrate by performing a plasma spray coating on the upper surface of the heat dissipating layer using the fine particles of the ceramic material; (b2) leveling the metal substrate that is bent through the thermal spraying process by performing a rolling process on the metal substrate on which the ceramic layer is formed; (b3) forming a correction layer 224 that fills the crack of the surface of the ceramic layer formed by the rolling process by laminating and thermally fusion a mixture of the thermosetting resin material and the ceramic-based material on top of the ceramic layer; step; And (b4) forming an insulating layer 226 that electrically insulates the electrically conductive layer from the heat dissipating layer by laminating and thermally bonding the thermosetting synthetic resin material on the correction layer.

In one embodiment, the ceramic-based material is aluminum oxide (Al2O3), the thermosetting resin material is characterized in that the thermosetting epoxy resin.

In one embodiment, step b3), the mixing ratio of the mixture is characterized in that the weight ratio of the thermosetting resin material is 5 times or more than 10 times less than the weight ratio of the ceramic material.

In one embodiment, in step b3), the mixing ratio of the mixture is characterized in that the thermosetting resin material: the ceramic material = 9: 1 weight ratio.

In another aspect, the present invention, the heat dissipation printed circuit board original plate used in the application field where the high heat radiation high voltage electric element is used, the heat dissipation layer 210 formed of a metal substrate having electrical conductivity; An intermediate layer 220 including a ceramic material having insulation and thermal conduction on the heat dissipation layer 210; And an electrically conductive layer 230 including a metallic material having electrical conductivity on the upper portion of the intermediate layer, wherein (b) the intermediate layer 220 uses fine particles of the ceramic material on the upper surface of the heat dissipating layer. A ceramic layer 222 including the ceramic-based material on top of the metal substrate by performing a plasma spray coating; A correction layer 224 formed by stacking and thermally bonding a mixture of the thermosetting resin and ceramic material on top of the ceramic layer, the correction layer 224 filling a crack in the surface of the ceramic layer generated by the rolling process. ); And an insulating layer 226 electrically insulating the electrically conductive layer and the heat dissipating layer by laminating and thermally bonding the thermosetting synthetic resin material on the correction layer.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

"Substrate" in the present invention means the lower support plate used in the heat dissipation printed circuit board.

FIG. 2 is a view showing a heat dissipation printed circuit board disc 200 according to the present invention, and FIG. 3 is a flowchart showing a method of manufacturing the heat dissipation printed circuit board disc 200 according to the present invention. 4F is a view showing a state of the original plate 200 formed in each manufacturing step of FIG.

In Figure 2, the heat dissipation printed circuit board original substrate 200 according to the present invention includes a heat dissipation layer 210, an intermediate layer 220 and an electrically conductive layer 230 from below, the intermediate layer 220 is a ceramic layer from below 222, a correction layer 224, and an insulating layer 226.

The heat dissipation layer 210 is formed of a metal substrate and functions to discharge heat generated from the electric element of the electric conductive layer 230 to the outside.

The intermediate layer 220 transfers heat from the conductive layer 230 to the heat dissipation layer 210 and at the same time electrically insulates the conductive layer 230 and the heat dissipation layer 210. Therefore, the intermediate layer 220 is made of a material having insulation and thermal conductivity.

The conductive layer 230 is connected to the electric element on the top and provides electrical conductivity according to the pattern between the electric elements. Therefore, the conductive layer is made of a material with high electrical conductivity.

The intermediate layer 220 includes a ceramic layer 222, a correction layer 224, and an insulating layer 226. The ceramic layer 222 is made of a ceramic-based material of aluminum oxide (Al 2 O 3) and simultaneously has insulation and thermal conductivity. In other words, the material is electrically conductive and heat is conductive. The correction layer 224 fills the cracks in the ceramic layer generated during the manufacturing process and is made of a thermosetting synthetic resin having high electrical insulation, preferably a thermosetting epoxy resin. The thermally conductive layer 226 increases the adhesion between the electrically conductive layer and the intermediate layer and at the same time serves to electrically insulate the electrically conductive layer and the intermediate layer.

Hereinafter, a method of manufacturing the disc 200 of FIG. 2 will be described with reference to FIGS. 4A to 4F and FIG. 5.

In step 310, as shown in FIG. 4A, the heat dissipation layer 210 is formed by cutting the metal substrate. An aluminum substrate is mainly used as the metal substrate, and a general cutting standard has a width * width = 510 * 510 to 610 * 610 mm and a thickness of 0.6 to 2.0 mm. The reason why the aluminum substrate is used is because of its high thermal conductivity.

In operation 320, an intermediate layer including a ceramic-based material having insulation and thermal conductivity is formed on a heat dissipation layer, that is, an upper surface of the metal substrate. This step is divided into steps 322 to 326.

In step 322, the ceramic layer 222 is formed on the metal substrate by performing a thermal spray (X) using fine particles of a ceramic material on the top surface of the heat dissipation layer. The ceramic material includes aluminum oxide fine particle component (Al 2 O 3) as a material having both insulation and thermal conductivity (see FIG. 4B). The fine particles P form a ceramic layer 222 and adhere to the upper portion of the metal substrate 310. In general, the thickness of the ceramic layer is preferably about 45 to 60㎛.

Thermal spray (溶 射) is widely known in the art as a coating technology for forming a laminated film by rapidly changing a powder or a linear material from a high temperature heat source into a molten liquid to impinge on the substrate at high speed and then solidified rapidly. This method requires heat sources such as high-density combustion flames, arcs and plasmas for heating and melting of the material. The technique of forming a film on the surface of the substrate by using different materials for thermal spraying is one of the surface treatment methods that make use of the characteristics possessed by the substrate, to compensate for defects, and to diversify and enhance material functions. In the thermal spraying method, materials such as metals, ceramics, glass plastics, and the like can be surface-treated, and in particular, if the material type and the unique characteristics of the thermal spraying process are used well, the surface layer that cannot be obtained by other methods can be produced. It is suitable for forming a layer.

In the present invention, plasma is used as a heat source, and plasma spraying using plasma is used. Plasma spray is also called Atmospheric Plasma Spraying. This thermal spraying method is a film forming technique in which gases such as Ar, He, N2, etc. are plasma-made by an arc, discharged from a nozzle, and a high-temperature, high-speed plasma jet is used as a heat source. The plasma generator is composed of a circular anode made of Cu and a cathode made of W, in which the electric arc discharge turns the working gas into plasma to form a jet. The flame temperature is 10,000-15,000 K, the flame speed is 150-300 m / s, and the Enthalpy is 16,000-20,000 J / l.

This spraying method is, firstly, a very easy and rather essential spraying technique for metal and ceramic coatings such as high melting point W and Mo. Second, if the material is accompanied by a stable melting phenomenon, such as metal, ceramics, the thermal spraying is possible, so the selection area of the coating material is high, which is more suitable for forming a ceramic film on a metal substrate as described herein. Third, because the speed of the plasma jet is large, the thermal spraying material collides with the workpiece at high speed, and thus it is possible to manufacture a coating film having high adhesion strength and high density. Fourth, because the large output is easy, the thermal spraying amount per unit time is large, workability is good and economical. Fifth, because it is oxygen-free, carbon-free and clean, thermochemically active heat source, there is little contamination and change of thermal spray material.

In step 324, the metal substrate, which is bent through the thermal spraying process, is leveled by performing a rolling process on the metal substrate on which the ceramic layer is formed in step 322.

Since a very high heat source is used in the thermal spraying step 322, material deformation is likely to occur after the thermal spraying process. In particular, the present invention aims to bring the ceramic material into close contact with the upper surface of the metal substrate, but due to a very large difference between the thermal conductivity of the metal substrate and the thermal conductivity of the ceramic material, as shown in FIG. 4B, a material warpage phenomenon occurs. do. Therefore, it is necessary to planarize the curved metal substrate, and in the present invention, the curved metal substrate is planarized through a rolling process.

5 is a diagram illustrating a rolling process.

Rolling process (rolling process) is a process of flattening the curved plate material using the ductility of the material by passing the flexible plate-like material between two or more rollers arranged side by side, which is well known in the art. In the present invention, since the metal substrate has a ductility as the metal material, it is suitable for performing the rolling process.

In step 326, a correction layer 224 is formed on the ceramic layer to fill the cracks on the surface of the ceramic layer generated by the rolling process by laminating and thermally bonding a mixture of the thermosetting resin material and the ceramic-based material.

As shown in FIG. 4D, crack c is generated on the surface of the ceramic layer after the rolling process of FIG. 5. This crack c is caused by the surface crack of the ceramic layer, which is relatively less ductile than the metal, when the curved metal substrate of FIG. 4B is unrolled through the roller R of FIG. This crack c causes a problem that electricity is conducted to the metal substrate 210 when a high withstand voltage is generated by the conductive layer 230. This is because the crack c portion is relatively low in heat transfer. Usually, the depth of this crack c is about 10-20 micrometers.

Therefore, as shown in FIG. 4D, the crack is filled by re-laminating the correction layer 224 on the upper surface of the ceramic layer 222 where the crack has occurred. Since the material of the correction layer 224 is a mixture of the thermosetting resin material M1 and the ceramic material M2, the filled cracks provide electrical insulation and provide high adhesion to the ceramic layer.

In this embodiment, a thermosetting epoxy resin is widely used as the thermosetting synthetic resin, and the same material as the ceramic layer, that is, aluminum oxide (Al 2 O 3) is widely used as the ceramic material.

Further, in the present embodiment, the weight ratio of the thermosetting resin and the ceramic material is preferably 5 to 10 times the weight ratio of the thermosetting synthetic resin material, in particular, the thermosetting synthetic resin material: ceramic material = Most preferred is 9: 1.

In this embodiment, it is preferable that the thickness of the correction layer is 12.5 W 3 µm except for the crack portion. This is because the correction layer is enough to correct the crack c.

In step 328, as shown in FIG. 4E, the conductive layer 230 and the metal substrate, that is, the heat generating layer 210 are electrically insulated by stacking and thermally bonding the thermosetting resin material on the correction layer 224. An insulating layer 226 is formed.

The insulating layer 226 is formed of only a thermosetting synthetic resin material, but is preferably a thermosetting epoxy resin. This is to increase adhesion to each other because the correction layer 224 in close contact with the insulating layer 226 is composed of a mixture containing a thermosetting resin. The insulating layer 226 serves two functions. One is an electrical insulation function of the electrically conductive layer 230 and the heating layer 220, and the other is an adhesion function of the correction layer 224 and the electrically conductive layer 230. Usually, the ceramic-based material is reduced in viscosity and adhesion, so that the metal copper foil process for forming the conductive layer 230 is not smoothly performed. Therefore, before forming the conductive layer, the adhesive layer with the conductive layer is increased by forming an insulating layer composed of only the thermosetting resin material.

As shown in FIG. 4E, the ceramic layer 222, the correction layer 224, and the insulating layer 226 together form the intermediate layer 220. The intermediate layer 220 includes a ceramic material and is positioned between the electrically conductive layer 230 and the heat dissipation layer 210 to provide electrical insulation and thermal conductivity.

In step 330, as shown in FIG. 4F, an electrically conductive layer is formed on the intermediate layer 220, that is, on the insulating layer 226, by forming a thin film of a copper material, preferably a metal material. 230). The method of forming the conductive layer 230 may be any conventional method, but preferably, a hot press method is widely used. It is preferable that an electrically conductive layer is 35 W 1 micrometer.

According to the present invention, since the intermediate layer is formed between the heat dissipating layer and the electric conductive layer using a ceramic material having high thermal conductivity, the heat dissipation characteristics are improved compared to the insulating layer made of conventional synthetic resins only. In addition, since the same ceramic layer also performs an insulating function, the height of the insulating layer can be reduced, and as a result, a problem of reducing the insulating property due to the insulating layer can be prevented. In addition, the difficulty of implementing the ceramic layer is solved through the correction layer.

In addition, according to the present invention, in the present invention, the insulating layer is divided into a ceramic layer and an insulating layer, and most of the insulating functions are provided by the ceramic layer. As a result, the insulating layer may function only as an adhesive function rather than an insulating function, and as a result, the thickness of the insulating layer may be designed to be very small, thereby preventing the blasting phenomenon of the foam component of the insulating layer made of synthetic resin as in the prior art. . Furthermore, since the blasting phenomenon of the foaming component is prevented, breakage of the electrically conductive layer is also prevented, thereby increasing the life of the product and reducing the unit cost.

In particular, in the present invention, a correction layer 224 filling the crack c, which is essential during the formation of the ceramic layer, is added to prevent a decrease in the breakdown voltage due to the crack. According to an experiment conducted by the present applicant, the original plate 100 has a withstand voltage of 2 to 3 kv, whereas the original plate 100 can withstand a case where the ceramic layer is formed and cracks are corrected according to the present invention. Withstand voltage was 4 ~ 4.5kv, withstand voltage increased by about 30-50% or more.

6 is a graph showing the effects of the present invention, which is a graph comparing the thermal conductivity of the original plate 200 with that of the conventional original plate 100.

Applicant measured the thermal conductivity of the present invention in comparison with various prior art and attached to FIG. This experiment was performed at the Korea Advanced Institute of Science and Technology (KAIST) on March 5, 2009.

In FIG. 6, the x axis represents temperature (in degrees Celsius) and the y axis represents thermal conductivity (watt / m * K). Meanwhile, in FIG. 6, each line means the following table.

Line segment Layer structure Thickness, capacity Diamond wire 2 of the present invention (intermediate layer) 76 μm, 1 oz Square line Conventional Structure A of Figure 1 (heat Transfer Layer) 123 μm, 1 oz Triangle line Conventional Structure B of Figure 1 (heat Transfer Layer) 168 μm, 1 oz x-ray Conventional Structure C of Figure 1 (heat Transfer Layer) 133 μm, 2 oz

The diamond wire is a graph of thermal conductivity when an intermediate layer 76 µm (ceramic layer 60 µm + heat transfer layer 16 µm) having a layer structure according to the present invention is formed. As shown in Figure 6, it can be seen that the thermal conductivity by the structure of the present invention shows an improvement in thermal conductivity of 20% to 70% over the prior arts A, B, and C over the entire range of temperature. In particular, when compared with the prior art C, it can be seen that the heat dissipation effect is about the same as that of the case where the constituent capacity of the heat dissipation layer is twice as large as about 2 times.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

As described above, according to the present invention, by applying an intermediate layer containing a ceramic-based material having both insulation and thermal conductivity, it is possible to increase the heat dissipation effect of the heat dissipation printed circuit board original plate that can be used for high heat dissipation electric element business such as high efficiency LED. Can be.

Further, according to the present invention, since the heat dissipation effect and the heat transfer effect are achieved by the ceramic layer, the layer containing the synthetic resin material is greatly reduced, thereby preventing the blasting phenomenon of the foaming component.

In addition, according to the present invention, since the ceramic layer is flattened by the correction layer and the rolling process, problems such as a decrease in breakdown voltage due to cracks are prevented.

In addition, according to the present invention, since the heat dissipation effect can be increased without reducing the insulation effect, it is possible to manufacture a heat dissipation printed circuit board that satisfies the industrial field to which a high heat dissipation high voltage electric element such as a high efficiency LED is applied.

Claims (5)

In the method for manufacturing a heat dissipation printed circuit board used in applications where high heat high voltage electric element is used, (a) forming a heat dissipation layer 210 by cutting the metal substrate; (b) forming an intermediate layer 220 including a ceramic material having insulation and thermal conduction on the heat dissipation layer 210; And (c) forming an electrically conductive layer 230 including a metallic material having electrical conductivity on top of the intermediate layer, Forming (b) the intermediate layer 220, (b1) forming a ceramic layer 222 including the ceramic-based material on the metal substrate by performing a plasma spray coating on the upper surface of the heat-dissipating layer using the fine particles of the ceramic-based material. step; (b2) leveling the metal substrate that is bent through the thermal spraying process by performing a rolling process on the metal substrate on which the ceramic layer is formed; (b3) forming a correction layer 224 to fill the cracks on the surface of the ceramic layer generated by the rolling process by laminating and thermally fusion a mixture of a thermosetting synthetic resin material and the ceramic-based material on the ceramic layer; ; And (b4) forming an insulating layer 226 that electrically insulates the electrically conductive layer from the heat dissipating layer by laminating and thermally bonding a thermosetting synthetic resin material on top of the correction layer; In step b3), The mixing ratio of the mixture is a method for producing a heat dissipation printed circuit board, characterized in that the weight ratio of the thermosetting synthetic resin material is not less than 5 times and 10 times less than the weight ratio of the ceramic material. The method of claim 1, wherein the ceramic material is aluminum oxide (Al2O3), and the thermosetting synthetic resin material is a thermosetting epoxy resin. delete The method of claim 1, wherein in step b3), The mixing ratio of the mixture is a thermosetting synthetic resin material: the ceramic-based material = 9: 1 weight ratio manufacturing method for manufacturing the original printed circuit board. In the disk for heat dissipation printed circuit board used in applications where high temperature high voltage electric element is used, A heat dissipation layer 210 formed of a metal substrate having electrical conductivity; An intermediate layer 220 including a ceramic material having insulation and thermal conduction on the heat dissipation layer 210; And An electrical conductive layer 230 including a metallic material having electrical conductivity on top of the intermediate layer, The intermediate layer 220, A ceramic layer 222 including the ceramic material on the upper surface of the metal substrate by performing a plasma spray coating on the upper surface of the heat dissipating layer using fine particles of the ceramic material; A correction layer 224 formed by laminating and thermally fusion a mixture of a thermosetting synthetic resin material and the ceramic-based material on top of the ceramic layer, the surface of the ceramic layer generated by the step of flattening the bent metal substrate after the thermal spraying process. A correction layer 224 filling the cracks; And An insulating layer 226 electrically insulating the electrically conductive layer and the heat dissipating layer by laminating and thermally bonding a thermosetting synthetic resin material on top of the correction layer, The mixing ratio of the mixture of the correction layer is a heat dissipation printed circuit board, characterized in that the weight ratio of the thermosetting synthetic resin material is at least 5 times 10 times less than the weight ratio of the ceramic material.

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