KR100995772B1 - Ceramic heat sink and its manufacturing method - Google Patents

Abstract

PURPOSE: A ceramic heat radiation plate and a manufacturing method thereof are provided to control a pore rate by controlling the amount of silicon carbide and inorganic bond. CONSTITUTION: Slurry is formed by dispersing silicon carbide agglomerate particles and inorganic binder agglomerate particles(S100). Uniform slurry is formed by attaching the inorganic binder on the surface of the silicon carbide agglomerate(S200). The uniform slurry is made of granule powder(S300). The granule powder is formed with a preset shape(S400). The formed body is thermally treated at 600 to 1200 degrees centigrade at 10°C/min and then is thermally treated at 1200 to 1600 degrees centigrade at 5°C/min(S500). The surface of the ceramic heat radiation plate is polished(S700).

Description

Ceramic heat sink and its manufacturing method

The present invention relates to a ceramic heat sink, and more particularly, to a ceramic heat sink having a cooling performance equal to or higher than that of a metal heat sink and capable of solving various problems caused by electromagnetic waves, and a method of manufacturing the same.

In general, a lot of heat is generated in the electrical and electronic products that use electricity. For example, if the heat generated from a product such as a circuit board with a light emitting diode (LED), a broadcast receiving device, a CPU, a refrigerator, a boiler, or the like is not discharged to the outside, electrical and electronic products may be deteriorated in operation efficiency, lifespan, Failure or the like will occur.

To prevent this, various heat dissipation devices are installed in the electrical and electronic products to release heat. Such heat dissipation devices have been disclosed, such as a blower for forcibly blown by rotating the fan by a motor, or a metal heat dissipation plate for lowering heat with air by increasing a surface area.

The blower can blow air rapidly to cool the electrical and electronic products, but additional electricity is consumed to rotate the motor, noise caused by the rotation of the fan and the motor, failure in continuous use (motor and fan The operation part), the recent trend in miniaturization, slimming is subject to design constraints due to the size of the blower. On the other hand, the metal heat sink is equipped with a plurality of heat dissipation fins to increase the surface area that can be contacted by air, thereby dissipating the heat generated by the electrical and electronic products in a natural state, so that the cooling rate of the heat is slower than that of the blower, but it can be used permanently for a long time. It can be used to prevent noise, and has been used a lot in recent years.

In the conventional metal heat sink 10 shown in FIG. 1, a plurality of metal heat dissipation fins 15 are formed at the bottom of the body 11 and the body 11. The metal heat sink 10 is made of copper, aluminum alloy, or the like, which has rapid heat conduction. The metal heat dissipation plate 10 is installed in parts of electrical and electronic products such as LED lamps 30 in which light emitting diodes LED 33 are provided on the circuit board 31, for example.

At this time, the metal heat sink 10 is installed on the bottom surface of the circuit board 31 on which the light emitting diodes 33 are installed to emit heat generated from the light emitting diodes 33 to the outside. For convenience of description, the light emitting diode 33 is provided on the circuit board 31, but electronic components such as a resistor and a capacitor are also installed.

In the conventional metal heat sink 10 as described above, since the metal of the bundle must be processed by NC lathe or milling in order to form the metal heat dissipation fins 15 on the body 11, there is a problem of raising the manufacturing cost due to the discarded portion. there was.

In particular, in the recent trend of miniaturization and slimming of electrical and electronic products, the conventional metal heat sink 10 has external leakage of electromagnetic waves caused by slimming of electrical and electronic products, and electronic components within and close to electrical components within electrical and electronic products due to miniaturization. There is a problem that may be the cause of malfunction due to mutual electromagnetic interference between them.

The ceramic heat sink having a microporous structure of Korea Patent No. 651151, which was devised in view of the above-described conventional problem, is a ceramic heat consisting of two layers, a heat dissipation layer and a heat conductive layer. It's a sink.

The heat dissipation layer allows the ceramic micro-cell structure to be formed by non-uniform dispersion of gel-like slurry using the liquid-liquid phase change principle by microscopic chemistry, wherein the ceramic micro-cell structure is 1 It is a structure having a microporous structure having a hollow crystals and having pores in the range of 5% to 40% by being combined with the powder of 탆 or less and sintered, wherein the heat conducting layer absorbs heat energy from a heat source, and the heat dissipating layer Has a microporous structure with hollow crystals, and the air acts as a medium for heat dissipation to improve the heat dissipation capacity.

The ceramic heat sink having a heat dissipation layer having a microporous structure of Korean Patent No. 651151 consisting of the heat dissipation layer and the heat conductive layer is formed on the contact surface of the heat dissipation layer. It is made of a structure for mounting a heat conductive layer (heat conductive layer) there is a problem that the production process is complicated and productivity may be reduced.

The object of the present invention devised in view of the above problems

First, by applying ceramic heat sinks that do not generate electromagnetic waves to electrical and electronic products, the ceramic heat sinks that satisfy the regulations of domestic and international EMC (Electromagnetic Compatibility) laws are manufactured.

Second, by using a ceramic heat sink that does not generate electromagnetic waves in electrical and electronic products, it is possible to suppress the leakage of electromagnetic waves due to the slimming of electrical and electronic products,

Third, by using a ceramic heat sink that does not generate electromagnetic waves in electrical and electronic products, it is possible to eliminate the cause of malfunction due to the interference of electromagnetic waves between the electronic components inside and the electrical and electronic products according to the miniaturization of electrical and electronic products. Can and

Fourth, compared to the ceramic heat sink manufactured by dividing the heat conduction layer and the heat dissipation layer into a single layer without any distinction, the manufacturing process of the product is simplified and the production process of the product is simple.

Fifth, the porosity can be adjusted by controlling the weight part of silicon carbide (SiC) and inorganic binder, which can adjust the specific surface area for heat dissipation in the same volume, and improve the heat dissipation effect, and the ceramic heat sink and its manufacture To provide a method.

This object is achieved by a ceramic heat sink comprising a 60 to 98 parts by weight of silicon carbide having a particle size of 1 ~ 300㎛ and 2 to 40 parts by weight of an inorganic binder.

The inorganic binder is achieved by a ceramic heat sink comprising a single oxide selected from Si, Al, Ca, Mg, Fe, Ti, K, Na group or two or more mixed oxides.

On the other hand, the specific gravity is 1.5 to 4.0, it is achieved by a ceramic heat sink characterized in that it has a porosity in the range of 3 to 45%.

In the manufacturing method for implementing the ceramic heat sink, in the method of manufacturing a ceramic heat sink, silicon carbide (SiC) aggregated particles and inorganic binder aggregated particles are mixed heterogeneously by adding a dispersant in an aqueous solution and inorganic particles. A dispersion step of dispersing binder agglomerated particles to produce a slurry; Adding an organic binder to the slurry prepared above to uniformly bond the inorganic binder to the silicon carbide (SiC) particle surface using the organic binder to prepare a uniform mixed slurry; A granulation process of spray drying the uniform mixed slurry prepared through the raw material particle bonding process to produce granule powder; A molding step of manufacturing the molded granules into a mold so as to form a predetermined shape after the granulation step is performed; A heat treatment step of heat-treating the molded product manufactured through the molding process in two steps; It is achieved by a method of manufacturing a ceramic heat sink characterized in that the manufacturing process in order to complete the product by processing the flatness of the ceramic heat sink manufactured through the heat treatment process.

Meanwhile, in the manufacturing method, a separation preventing process for increasing the adhesive force of the organic binder which bonds the inorganic binder on the surface of the silicon carbide (SiC) particles through the ultrasonic vibration is added to the uniform mixed slurry produced through the raw material particle bonding process It can also be done.

Such a ceramic heat sink of the present invention is the electromagnetic wave leakage to the outside due to the slimming caused by the use of a metal heat sink for the heat dissipation of electrical and electronic products, the mutual electromagnetic waves between the electronic components within the electrical and electronic products and the adjacent electrical and electronic products by miniaturization Ceramic material which does not generate electromagnetic waves which is a cause of malfunction due to interference is used to fundamentally eliminate the cause of such problems and to improve the reliability of the product and to provide a ceramic material having a cooling performance equal to or higher than the cooling performance of the metal heat sink The manufacturing process of the product is simplified because it is composed of a single layer without distinguishing between the heat conduction layer and the heat dissipating layer as compared with the manufacturing process in which the ceramic heat dissipating plate manufactured by using the heat conduction layer and the heat dissipating layer is divided into the existing heat conduction layer and the heat dissipating layer. Simple, by controlling the amount of silicon carbide (SiC) and inorganic binder It is possible to control the porosity, which is a very useful invention having the advantage of being able to adjust the specific surface area for heat dissipation in the same volume to improve the heat dissipation effect.

1 is a cross-sectional view showing the structure of a heat sink made of a conventional metal material.
Figure 2 is a process diagram showing a method of manufacturing a heat sink to which the technique of the present invention is applied.
Figure 3 is a process diagram showing another manufacturing method of the heat sink to which the technique of the present invention is applied.

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

2 is a process chart showing the structure of a heat sink to which the technique of the present invention is applied. According to the ceramic heat sink of the present invention, silicon carbide (SiC) agglomerated particles and inorganic binder agglomerated particles having a particle size of 1 to 300 μm are formed in an aqueous solution. The dispersion process (S100) of dispersing heterogeneously mixed silicon carbide (SiC) aggregated particles and inorganic binder aggregated particles by mixing with a dispersant to produce a slurry in which raw materials are uniformly mixed is performed.

The reason for dispersing the silicon carbide (SiC) agglomerated particles and the inorganic binder agglomerated particles is that the silicon carbide (SiC) particles and the inorganic binder particles are agglomerated in a state in which the raw materials are mixed to produce a granular powder. This is because the reduction in the cooling performance of the product is caused by the difference in the thermal conductivity due to the distribution and variation in the composition of the raw materials for each part of the final product.

The inorganic binder may be formed of a single oxide selected from Si, Al, Ca, Mg, Fe, Ti, K, Na or two or more mixed oxides, and the organic binder may be added to the slurry prepared by the dispersion process (S100). By adding the organic binder to the surface of the silicon carbide (SiC) particles using an organic binder uniformly to perform a raw material bonding process (S200) to produce a uniform mixed slurry.

After performing the raw material combining process (S200) by spray-drying the prepared slurry to perform a granulation process (S300) to produce a granule (granule) powder. After performing the granulation process (S300) is put into a mold to form a granular powder is formed in a predetermined shape to perform a molding process (S400) to pressurized at room temperature at a constant high pressure to produce a molded body.

On the other hand, the manufactured molded article is subjected to a heat treatment step (S500). The heat treatment process is to be manufactured through a heat treatment process having a temperature increase rate of two stages. The first step heat treatment step (S500a) is 600 ~ 1200 ℃ below the bonding temperature of the inorganic binder, the first step heat treatment step (S500a) is subjected to a high temperature increase rate of 10 ℃ / min and the molded body in the first step heat treatment step (S500a) All organic binders are thermally decomposed and removed.

After the first step heat treatment step (S500a) the molded body is subjected to a two-step heat treatment step (S500b) at 1200 ~ 1600 ℃. The two-stage heat treatment process (S500b) is a temperature increase without uniform temperature distribution of the inorganic binder uniformly distributed inside the molded body at a low temperature increase rate of 5 ℃ / min to uniformly bond between the silicon carbide (SiC) particles A uniform joint (SiC-SiC neck) is produced throughout.

The reason for forming a uniform bonding portion throughout the product is that the inorganic binder is heated up uniformly without uniformly raising the inorganic binder to bond the silicon carbide particles with the silicon carbide particles, thereby locally bonding the silicon carbide particles with the silicon carbide particles. This is because the phenomenon that the strength of the product is lowered and the short circuit of the thermal conduction is shortened and the cooling performance of the product is lowered.

The ceramic heat sink product of the two-step heat treatment (S500b) is subjected to the processing step (S700). The processing step (S700) is a polishing process for removing the chips (such as the increase in flatness) and the edge of the product in order to attach the ceramic heat sink to the heating parts of the electrical and electronic products without lifting the phenomenon. It is manufactured through.

The ceramic heat sink manufactured after the processing step (S700) is composed of 60 to 98 parts by weight of silicon carbide having a particle size of 1 ~ 300㎛ and 2 to 40 parts by weight of the inorganic binder. In addition, the heat sink has a specific gravity of 1.5 to 4.0 and has a porosity in the range of 3 to 45%.

Meanwhile, as shown in FIG. 3, an adhesive force of an organic binder for bonding an inorganic binder on the surface of silicon carbide (SiC) particles through ultrasonic vibration of a slurry uniformly mixed by the raw material bonding process (S200). Separation prevention process (S800) to increase the can be further performed.

If the separation prevention process (S800) as described above is further carried out to increase the adhesive strength of the organic binder for bonding the inorganic binder on the surface of the silicon carbide (SiC) particles, and the increased adhesive strength can improve the quality and reliability of the product. .

Meanwhile, thermal conductivity and cooling performance are shown in Tables 1 and 2 below through experiments according to silicon carbide (SiC) particle size and silicon carbide (SiC) content used in the manufacture of a ceramic heat sink.

Experimental Method

Experimental conditions

1) Air temperature: 20 ± 1 ℃

2) Heating element temperature: 80 ± 0.5 ℃

3) Cooling capacity measurement time: 60 minutes

  As described above, a heat sink was attached to a heating element that generates a constant temperature (80 ± 0.5 ° C.) in a stable space maintained at a constant atmospheric temperature (20 ± 1 ° C.), and the temperature change was measured for 1 hour.

4) size

Width: 20mm

Length: 20mm

Thickness: 2.5mm

Table 1

 Comparison of the thermal conductivity of a conventional heat sink having a composite structure of a heat dissipation layer and a heat conduction layer and a ceramic heat sink to which the technique of the present invention is applied

[Table 2] Comparison of cooling performance between the conventional ceramic heat sink and the conventional metal heat sink and the ceramic heat sink of the present invention having a composite structure of the heat dissipation layer and the heat conducting layer

S100: Dispersion Process
S200: Raw Material Bonding Process
S300: Granulation Process
S400: Molding Process
S500: Heat Treatment Process
S500a: 1 step heat treatment process
S500b: Two stage heat treatment process
S700: Machining Process

Claims (6)

delete 60 to 98 parts by weight of silicon carbide having a particle size of 1 ~ 300㎛ and 2 to 40 parts by weight of the inorganic binder is a microporous structure having a porosity of 3 to 45% by mixing, molding and sintering, the inorganic binder is Si, Al, Ca , Mg, Fe, Ti, K, Na selected from the group consisting of a single oxide or two or more mixed oxide ceramic heat sink.
The ceramic heat sink of claim 2, wherein specific gravity of the ceramic heat sink is 1.5 to 4.0.
delete (SiC), which is a single oxide or a mixed oxide of two or more selected from the group consisting of Si, Al, Ca, Mg, Fe, Ti, K and Na and a silicon carbide A dispersion step of dispersing agglomerated particles and inorganic binder agglomerated particles to prepare a slurry;
A raw material bonding step of adding an organic binder to the slurry prepared above to homogeneously bond an inorganic binder to the surface of silicon carbide (SiC) particles using an organic binder to produce a uniform mixed slurry;
A granulation process of spray drying the uniform slurry prepared through the raw material combining process to produce granule powder;
A molding step of manufacturing the molded granules into a mold so as to form a predetermined shape after the granulation step is performed;
A heat treatment step of performing a second heat treatment at 1200 to 1600 ° C. at a low rate of 5 ° C./min after the first heat treatment of the molded product manufactured through the molding process at a temperature of 600 ° C./1200° C. at a rate of 10 ° C./min;
The method of manufacturing a ceramic heat sink characterized in that the manufacturing process in order to finish the product by polishing the surface of the ceramic heat sink manufactured by the heat treatment step.

[Claim 6] The ceramic heat sink of claim 5, further comprising a separation prevention step of adhering the inorganic binder on the surface of the silicon carbide (SiC) particles through ultrasonic vibration to the slurry of the dispersion process to increase the adhesion of the organic binder. Manufacturing method.

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