KR20200019068A - Boroncarbide sintered body and etch apparatus comprising the same - Google Patents

Abstract

A boron carbide sintered body of the present invention is characterized in that boron carbide containing particles are necked and the thermal conductivity value measured at 400°C is 27 W/(m*k) or less. The boron carbide sintered body has a thermal conductivity value within a specific range and has the excellent corrosion resistance and etch resistance properties.

Description

Boron carbide sintered body and etching apparatus including the same {BORONCARBIDE SINTERED BODY AND ETCH APPARATUS COMPRISING THE SAME}

The present invention relates to a boron carbide sintered body and an etching apparatus including the same.

Boron carbide (B ₄ C) is the second highest wear resistant ceramic after diamond and cubic boron nitride (BN). Boron carbide is known as a high hardness, high non-elastic material with high melting point (2447 ° C.), high strength (28-35 GPa, Knoop hardness), low density (2.21 g / cm ³ ), and high Young's modulus (450-470 GPa). In addition, it has high thermoelectric power and good chemical stability, so it is used not only for thermocouples used in molten metal for a long time but also has high neutron absorption ability, and has been used as a neutron absorber and shielding material for nuclear power for a long time.

Boron carbide (B ₄ C) is used as an abrasive material or a cutting tool material. For the sintering of such boron carbide (B ₄ C) powder, carbon (C), Y ₂ O ₃ , SiC, Al ₂ O ₃ , TiB ₂ , Sintering aids such as AlF ₃ , W ₂ B ₅ can be applied. However, such a sintering aid is known to form a secondary phase, and the secondary phase formed by sintering with the sintering aid may adversely affect the physical properties of boron carbide (B ₄ C).

Domestic Publication No. 10-2010-0033696, Mar. 31, 2010 Domestic Publication No. 10-2014-0147892, December 30, 2014

It is an object of the present invention to provide a boron carbide sintered body having excellent properties and an etching apparatus including the same in at least a part thereof.

In order to achieve the above object, one aspect of the present invention provides a boron carbide sintered body in which boron carbide-containing particles are necked and have a thermal conductivity value of 27 W / (m * k) or less measured at 400 ° C.

The boron carbide sintered body may have a ratio of a thermal conductivity value measured at 25 ° C. and a thermal conductivity value measured at 800 ° C. in a range of 1: 0.2 to 3.

The particles may have a particle diameter (D ₅₀ ) of 1.5 um or less.

The boron carbide sintered body may have a Ra roughness measured on a surface of about 0.1 μm to about 1.2 μm.

The boron carbide sintered body may not form particles by contacting fluorine ions in the plasma etching equipment.

The boron carbide sintered body may not form particles by contacting with chlorine ions in the plasma etching equipment.

The boron carbide sintered body may have a porosity of 3% or less.

The boron carbide sintered body may have an average diameter of pores observed at a surface or a cross section of 5 μm or less.

The boron carbide sintered body may have an area of 5% or less in an area having a diameter of 10 μm or more of pores observed from a surface or a cross section.

The boron carbide sintered body may have an etching rate of 55% or less than that of silicon.

The boron carbide sintered body may have an etching rate of 70% or less than that of CVD-SiC.

Another aspect of the present invention provides a component for an etching apparatus including the above-described boron carbide sintered body in part or all thereof.

Another aspect of the present invention provides an etching apparatus including at least a portion of the boron carbide sintered body described above.

The etching apparatus may be a plasma etching apparatus.

The boron carbide sintered body or the like of the present invention can provide a boron carbide sintered body having a relatively constant thermal conductivity, low etching rate (excellent corrosion resistance), and the like.

Since the boron carbide sintered body of the present invention does not substantially form particles by reacting with halogen ions such as fluorine ions or chlorine ions, it is suitable to be applied to at least a portion of an etching apparatus such as a plasma etching apparatus, and is controlled at low etching rate and reaction conditions. Its thermal conductivity makes it possible to use it as a consumable component in etching devices and improves its etch efficiency.

(A) and (b) are the surface observation results of the sintered compact manufactured by manufacture example 2 and manufacture example 3, respectively.
(A) and (b) are the surface observation results of the sintered compact manufactured by manufacture example 5 and manufacture example 6, respectively.
(A) and (b) are the surface observation results of the sintered compact manufactured by manufacture example 7 and manufacture example 8, respectively.
4 (a) and 4 (b) show observation results before and after etching of the sintered body prepared in Production Example 5, respectively.
5 (a) and 5 (b) show observation results before and after etching of the sintered body prepared in Production Example 8, respectively.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Like parts are designated by like reference numerals throughout the specification.

Throughout this specification, the term "combination of these" included in the expression of the makushi form means one or more mixtures or combinations selected from the group consisting of constituents described in the expression of the makushi form, wherein the constituents It means to include one or more selected from the group consisting of.

Throughout this specification, terms such as “first”, “second” or “A”, “B” are used to distinguish the same terms from each other. Also, the singular forms “a”, “an” and “the” include plural forms unless the context clearly indicates otherwise.

In the present specification, the singular forms “a,” “an” and “the” are intended to be interpreted in the context of the singular or plural, unless the context describes otherwise.

Boron carbide herein refers to all compounds based on boron and carbon. In the present specification, the boron carbide may be a single phase or a complex phase, and they may be mixed. The boron carbide single phase includes both the stoichiometric phase of boron and carbon and the nonstoichiometric phase deviating from the stoichiometric composition, wherein the complex phase is at least two of the compounds based on boron and carbon It means that the dog is mixed at a predetermined ratio. In addition, the boron carbide in the present specification includes both the case where impurities are added to the single phase or the complex phase of the boron carbide to form a solid solution or inevitable addition of impurities in the process of producing boron carbide. Examples of the impurity include metals such as iron, copper, chromium, nickel, and aluminum.

Hereinafter, the present invention will be described in more detail.

In order to achieve the above object, the boron carbide sintered body according to an embodiment of the present invention is a boron carbide-containing particles are necked, the thermal conductivity measured at 400 ℃ is 27 W / (m * k) or less.

The boron carbide sintered body has a thermal conductivity value measured at ₂₅ ℃ (HC 25) and the ratio of the thermal conductivity value (HC ₈₀₀₎ was measured at _{800 ℃ (HC 800 / HC 25} ) is 1: to have features from 0.2 to 3 have. Specifically, the ratio (HC ₈₀₀ / HC ₂₅ ) may be 1: 0.26 to 1, 1: 1: may be 0.26 to 0.6.

In the case of having such a thermal conductivity value, even if the temperature change of the atmosphere to which the sintered body is applied has a large thermal conductivity value within a certain range, it can have a relatively constant thermal characteristic even when applied to an atmosphere having a large temperature change. Process progress is possible. In order to adjust the thermal conductivity of the focus ring, additives such as silicon carbide or silicon may be used.

The thermal conductivity of the sintered compact may be about 60 W / (m * k) or less at 25 to 800 ° C., and about 4 W / (m * K) to about 40 W / (m * K). Also, in more detail, it may be about 4W / (m * K) to about 27W / (m * K).

The thermal conductivity of the sintered compact may be about 22 to about 80 W / (m * K) at 25 ° C., and may be about 22 to about 31 W / (m * K).

The thermal conductivity of the sintered compact may be about 7 to about 70 W / (m * K) at 400 ° C., and may be about 8 to about 22 W / (m * K).

The thermal conductivity of the sintered compact may be about 5 to about 50 W / (m * K), and about 6 to about 16 W / (m * K) at 800 ° C.

The sintered body may be one in which boron carbide-containing particles having a particle size (D ₅₀ ) of about 1.5 μm or less are sintered and necked. Details of the method of sintering and necking overlap with the description of the manufacturing method described later, so the description thereof is omitted.

Ra roughness of the boron carbide sintered body may be about 1.0㎛ to about 1.2㎛. Ra roughness of the polished sintered compact may be about 0.2 ㎛ to about 0.4 ㎛. The measurement can be applied to a three-dimensional measuring instrument. The boron carbide sintered body having such a surface roughness may have a smoother surface, and thus may exhibit excellent physical properties even when applied to a part or all of the parts applied to the etching device or to the etching device.

The porosity of the boron carbide sintered body may be about 10% or less. In more detail, the porosity of the boron carbide sintered body may be about 5% or less. In more detail, the porosity of the boron carbide sintered body may be about 3% or less. In more detail, the porosity of the boron carbide sintered body may be about 2% or less. In more detail, the porosity of the boron carbide sintered body may be about 1% or less. In more detail, the porosity of the boron carbide sintered body may be about 0.5% or less. In more detail, the porosity of the boron carbide sintered body may be about 0.1% or less. Such a sintered compact having a low porosity means a sintered compact having a lower carbon region or the like between particles, and may have stronger corrosion resistance.

In the boron carbide sintered body, an average diameter of pores may be 5 μm or less based on the cross section. At this time, the average diameter of the pores is derived as the diameter of the circle of the same area as the cross-sectional area of the pores. The average diameter of the pores may be 3㎛ or less. In more detail, the average diameter of the pores may be 1 μm or less. In addition, based on the total area of the pores, the area of the pore diameter of 10㎛ or more may be 5% or less. This means that the boron carbide sintered body has a relatively dense structure, and the dense structure is well distributed throughout the sintered body. In addition, since the boron carbide sintered body has such a compact structure, it may have improved corrosion resistance.

The boron carbide sintered body may contain 100 ppm or less of metal by-products (impurities), 10 ppm or less, may be 1 ppm or less, and substantially no metallic by-products (impurities).

The boron carbide sintered body may have an advantage of not forming particles (particulate foreign matter) by reacting with halogen ions in an etching apparatus. In this case, the particles refer to a material having a particle size of 1um or more. Specifically, the boron carbide sintered body may not form particles by reacting with fluorine ions in the plasma etching equipment. Specifically, the boron carbide sintered body may not form particles by reacting with chlorine ions in the plasma etching equipment. This feature is distinguished from the fact that the sintered body to which iridium or the like is applied can react with halogen ions to form particulate foreign matter, and the boron carbide sintered body is advantageous to be applied in an etching apparatus.

The silicon carbide sintered body has a low etching rate characteristic. Specifically, when the etching rate of silicon (Si, single crystal silicon, manufactured by the drawing method) is 100%, the silicon carbide sintered body may have an etching rate of 55% or less, and may have an etching rate of 10 to 50%. , An etching rate of 20 to 45%. The etching rate characteristics are based on the thickness reduction rate (%). Specifically, the above etching rate is a result of evaluating the etching rate under the same conditions where the RF power is 2,000W and the exposure time is 280 hr.

The low etch rate characteristics of the silicon carbide sintered body are superior to CVD-SiC, resulting in a fairly good etch rate. More specifically, the silicon carbide sintered body may have an etching rate of 70% or less when the etching rate of CVD-SiC is 100%.

The boron carbide sintered body may have high resistance, medium resistance, or low resistance.

Specifically, the boron carbide sintered body having a high resistance characteristic may have a specific resistance of about 10 Ω · cm to about 10 ³ Ω · cm. In this case, the high-resistance boron carbide sintered body is mainly formed of boron carbide, and may include silicon carbide or silicon nitride as a sintering characteristics improving agent.

Specifically, the boron carbide sintered body having a medium resistance characteristic may have a specific resistance of about 1 Ω · cm to less than 10 Ω · cm. In this case, the medium resistance boron carbide sintered body is mainly formed of boron carbide, it may include boron nitride as a sintering characteristics improving agent.

Specifically, the boron carbide sintered body having low resistance characteristics may have a specific resistance of about 10 ⁻¹ Ω · cm to about 10 ⁻² Ω · cm. In this case, the low-resistance boron carbide sintered body is mainly formed of silicon carbide, and may include carbon as a sintering characteristic improving agent.

More specifically, the silicon carbide sintered body may have a low resistance characteristic of 5.0 Ω · cm or less, may have a low resistance characteristic of 1.0 Ω · cm or less, and a low resistance characteristic of 8 * 10 ⁻¹ Ω · cm or less May have

The silicon carbide sintered body of the present invention has low etch rate characteristics, has excellent microstructural characteristics such as reduced carbon area as a whole in the cross-sectional observation results, and is excellent in utilization as an etch resistant member or the like.

The etching apparatus according to another embodiment of the present invention includes at least a portion of the boron carbide sintered body described above. Specifically, the boron carbide sintered body may be applied to a wall of a plasma reactor, a nozzle for a processing gas, a shower head for a processing gas, and the like.

Etching device components according to another embodiment of the present invention may include at least a portion of the boron carbide sintered body described above or may be made of the boron carbide sintered body. Specifically, the boron carbide sintered body may be applied to consumable parts such as focus rings and edge rings, and may be applied to consumable parts for a longer time while reducing defect rates in an etching process performed by an etching apparatus, thereby improving efficiency. You can.

A method of manufacturing a boron carbide sintered body according to another embodiment of the present invention includes a primary molding step and a sintered body forming step. The manufacturing method may further include a granulation step before the first molding step. The manufacturing method may further include a processing step after the sintered body forming step.

In the granulation step, a slurrying process of preparing a slurryed raw material by mixing a raw material containing boron carbide with a solvent, and granulation of drying the slurryed raw material into a spherical granular raw material Process.

The raw material may be a raw material including boron carbide and a sintering property improving agent.

The boron carbide (boron carbide, boron carbide) is represented by B ₄ C, the boron carbide of the raw material may be applied to powder boron carbide.

The boron carbide powder may have an average particle diameter of about 1.5 μm or less, an average particle diameter of about 0.3 μm to about 1.5 μm, and an average particle diameter of about 0.4 μm to about 1.0 μm on the basis of D ₅₀ . have. In addition, the boron carbide powder may have an average particle diameter of about 0.4 μm to about 0.8 μm based on D ₅₀ . When the boron carbide powder having an average particle diameter is too large, the density of the manufactured sintered compact may be lowered and corrosion resistance may be lowered. If the particle diameter is too small, workability may be lowered or productivity may be lowered.

The sintering characteristic improving agent is included in the raw material to improve physical properties of the boron carbide sintered body. Specifically, the sintering property improving agent may be any one selected from the group consisting of carbon, boron oxide, silicon, silicon carbide, silicon oxide, boron nitride, boron nitride, silicon nitride and combinations thereof.

The sintering property improving agent may be contained in about 0.1% to about 30% by weight, based on the entire raw material, may be contained in 1 to 25% by weight, may be contained in 5 to 25% by weight. When the sintering property improving agent is included in less than 0.1% by weight based on the entire raw material, the effect of improving the sintering properties may be insignificant, and when included in more than 30% by weight, the strength of the sintered body may be lowered.

The raw material may include a boron carbide raw material such as boron carbide powder in the remaining amount other than the sintering characteristic improving agent.

The sintering property improving agent may include boron oxide, carbon, and combinations thereof.

When carbon is applied as the sintering property improving agent, the carbon may be added in the form of a resin, and the resin may be applied to the carbon in the carbonized form through a carbonization process. In the carbonization process of the resin, a process of carbonizing a polymer resin may be generally applied.

When carbon is applied as the sintering property improving agent, the carbon may be applied in an amount of 1 to 30% by weight, 5 to 30% by weight, 8 to 28% by weight, and 13 to 23% by weight. Can be applied. When carbon is used as the sintering property improving agent in such a content, a necking phenomenon between particles increases, a particle size is relatively large, and a boron carbide sintered body having a relatively high relative density can be obtained. However, when the carbon is included in more than 30% by weight, the degree can be reduced by the generation of the carbon region by the residual carbon.

The sintered properties improving agent may be applied to boron oxide. The boron oxide is represented by B ₂ O ₃ , by applying the boron oxide to produce boron carbide through a chemical reaction with the carbon present in the pores of the sintered body, and help the discharge of residual carbon more compacted sintered body Can provide

When the boron oxide and the carbon are applied together as the sintering property improving agent, the relative density of the sintered body can be further increased, which can reduce the area of carbon present in the pores and can produce a sintered body having higher density.

The boron oxide and the carbon may be applied in a weight ratio of 1: 0.8 to 4, 1: may be applied in a weight ratio of 1.2 to 3, 1: 1: may be applied in a weight ratio of 1.5 to 2.5. In this case, a sintered body having an improved relative density can be obtained. More specifically, the raw material may contain 1 to 9% by weight of the boron oxide and 5 to 15% by weight of carbon. In this case, the sintered compact may have a considerably superior density and less defects. .

In addition, the sintering characteristics improving agent may have a melting point of about 100 ℃ to about 1000 ℃. In more detail, the melting point of the additive may be from about 150 ° C to about 800 ° C. The melting point of the additive may be about 200 ° C to about 400 ° C. Accordingly, the additive may be easily diffused between the boron carbide in the process of sintering the raw material.

The solvent applied for slurrying in the granulation step may be alcohol or water, such as ethanol. The solvent may be applied in an amount of about 60% by volume to about 80% by volume based on the entirety of the slurry.

The slurrying process may be a ball mill method. In the ball mill method, specifically, a polymer ball may be applied, and the slurry blending process may be performed for about 5 hours to about 20 hours.

In addition, the granulation process may be performed in such a way that the raw material is granulated while the slurry is sprayed and the solvent contained in the slurry is removed by evaporation. The granulated raw material particles thus prepared are characterized in that the particles themselves have a round shape and a relatively constant particle size.

The raw material particles may have a diameter of about 0.3 to about 1.5 μm, about 0.4 μm to about 1.0 μm, and about 0.4 μm to about 0.8 μm based on D ₅₀ .

When the granulated raw material particles are applied, the mold may be easily filled in the green body during the first molding step to be described later, and workability may be further improved.

The first molding step is a step of forming a green body by molding a raw material containing boron carbide. Specifically, the molding may be applied to press the raw material into a mold (rubber, etc.). More specifically, the forming may be cold isostatic pressing (Cold Isostatic Pressing, CIP) may be applied.

When the first molding step is performed by applying cold isostatic pressing, it is more efficient to apply the pressure at about 100 MPa to about 200 MPa.

The green body may be manufactured in consideration of the size and shape suitable for the use of the sintered body is manufactured.

The green body, it is preferable to form a size slightly larger than the size of the final sintered body to be manufactured, since the strength of the sintered body is stronger than the strength of the green body, the green body after the first molding step for the purpose of reducing the processing time of the sintered body Form processing to remove unnecessary parts from the body can be further proceeded.

The sintered body forming step is a step of producing a boron carbide sintered body by carbonizing and sintering the green body.

The carbonization may be performed at a temperature of about 600 ° C. to about 900 ° C., and in this process, binders or unnecessary foreign substances in the green body may be removed.

The sintering may be performed in such a manner as to maintain the sintering time of about 10 hours to about 20 hours at a sintering temperature of about 1800 ° C to about 2500 ° C. In this sintering process, the growth and necking between the particles of the raw material proceed and a densified sintered compact can be obtained.

Specifically, the sintering may be performed in a temperature profile of temperature raising, maintaining, and cooling, and specifically, the temperature of the first elevated temperature-first temperature maintenance-secondary temperature-second temperature-maintenance-secondary temperature--3rd temperature maintenance-cooling You can proceed to the profile.

The temperature increase rate in the sintering may be about 1 ° C / min to about 10 ° C / min. More specifically, the rate of temperature increase in the sintering can be from about 2 ° C / min to about 5 ° C / min.

In the sintering, a temperature of about 100 ° C. to about 250 ° C. may be maintained for about 20 minutes to about 40 minutes. In addition, the temperature range of about 250 ℃ to about 350 ℃ in the sintering may be maintained for about 4 hours to about 8 hours. In addition, the temperature range of about 360 ℃ to about 500 ℃ in the sintering may be maintained for about 4 hours to about 8 hours. When maintained for a predetermined time in the above temperature range, the additive can be more easily diffused, it is possible to produce a more uniform phase boron carbide sintered body.

The sintering may be maintained at a temperature section of about 1800 ℃ to about 2500 ℃ about 10 hours to about 20 hours. In this case, a more robust sintered body can be produced.

The cooling rate in the sintering may be about 1 ° C / min to about 10 ° C / min. More specifically, the cooling rate in the sintering may be about 2 ° C / min to about 5 ° C / min.

The boron carbide sintered body manufactured in the sintered body forming step may additionally undergo a processing step including surface processing and / or shape processing.

The surface processing is an operation to planarize the surface of the sintered body, and a method generally applied to planarizing a ceramic may be applied.

The shape processing is a process of removing or scraping a portion of the sintered compact to have an intended shape. The shape processing may be performed by the discharge machining method, in consideration of the fact that the boron carbide sintered body has excellent density and strong strength, and specifically, may be performed by the discharge wire processing method.

Specifically, the sintered body may be stored in a water tank, and after a direct current power source is connected to the sintered body and the wire, respectively, the wire may be reciprocated to cut a portion to be removed from the sintered body. At this time, the voltage of the DC power supply may be about 100 volts to about 120 volts, the processing speed may be about 2mm / min to about 7mm / min, the wire speed may be about 10rpm to about 15rpm, the tension of the wire Silver may be about 8 g to about 13 g, and the diameter of the wire may be about 0.1 mm to about 0.5 mm.

The sintered body thus produced has the features described above.

The method for producing a boron carbide sintered body according to another embodiment of the present invention includes a preparation step, a batching step, and a molding step.

The preparation step is a step of charging the raw material containing boron carbide into the hollow located in the molding die.

The hollow may be cylindrical or disc shaped, and two or more cylindrical or disc shaped different in size and height from each other may be stacked. Specifically, the hollow may include a first hollow and a second hollow having a difference in size and height so as to be positioned up and down with each other and distinguished from each other. The height of the first hollow may be higher than the height of the second hollow. The size of the first hole may be smaller than the size of the second hole.

The boron carbide (boron carbide, boron carbide) is represented by B ₄ C, the boron carbide of the raw material may be applied to powder boron carbide.

The raw material may contain boron carbide powder, may contain boron carbide powder and additives, and may be made of boron carbide powder. The boron carbide powder may be applied with high purity (boron carbide content of 99.9% by weight or more), and low purity (boron carbide content of 95% by weight or more and less than 99.9% by weight) may be applied.

The boron carbide powder may have an average particle diameter of about 1.5 μm or less, an average particle diameter of about 0.3 μm to about 1.5 μm, and an average particle diameter of about 0.4 μm to about 1.0 μm on the basis of D50. . In addition, the boron carbide powder may have an average particle diameter of about 0.4 μm to about 0.8 μm based on D50. When the boron carbide powder is applied, a boron carbide sintered compact body having less pore formation can be produced.

The additive may be a functional additive that forms a boron carbide solid solution in part or all of the boron carbide sintered body to impart functionality to the boron carbide sintered body.

The additive may be a sintering characteristic improving agent applied for the purpose of improving the sintering characteristics of the boron carbide sintered body. The sintering property improving agent may be any one selected from the group consisting of carbon, boron oxide, silicon, silicon carbide, silicon oxide, boron nitride, boron nitride, silicon nitride, and combinations thereof. The sintering property improving agent may include boron oxide, carbon, and combinations thereof. When carbon is applied as the sintering property improving agent, the carbon may be added in the form of a resin, and the resin may be applied to the carbon in the carbonized form through a carbonization process. In the carbonization process of the resin, a process of carbonizing a polymer resin may be generally applied.

Specifically, the sintering property improving agent may be included in about 30% by weight or less based on the entire raw material, may be contained in about 0.001% to about 30% by weight, may be contained in 0.1 to 25% by weight , 5 to 25% by weight.

When the sintering property improving agent is included in more than 30% by weight based on the entire raw material, rather it may lower the strength of the manufactured sintered body.

The die may be formed by combining two or more divided pieces with each other.

The method of manufacturing the boron carbide sintered body may be made of a material such as graphite having a high temperature comparative strength with the molding die so that a strong sintering pressure may be applied, and a reinforcing part for reinforcing the molding die may be applied as necessary.

The placing step is to charge the die into a sintering furnace or chamber and to set the pressurization portion. The sintering furnace or chamber applied in the batching step may be applied without limitation as long as it is a device capable of manufacturing the boron carbide sintered body in a high temperature pressurized atmosphere.

The forming step is a step of forming a boron carbide sintered body from the raw material by applying a sintering temperature and a sintering pressure to the die.

The die may be manufactured to have a desired product shape relatively easily by forming a hollow in advance in the shape to be manufactured by the boron carbide sintered body of the present invention as described later.

The sintering temperature may be about 1800 to about 2500 ℃, may be about 1800 to about 2200 ℃. The sintering pressure may be about 10 to about 110 MPa, about 15 to about 60 MPa, may be about 17 to about 30 MPa. When the molding step is performed under such sintering temperature and sintering pressure, a high quality boron carbide sintered body can be produced more efficiently.

The sintering time may be applied 0.5 to 10 hours, 0.5 to 7 hours may be applied, 0.5 to 6 hours may be applied.

The sintering time is a considerably shorter time compared to the sintering process which proceeds at normal pressure, and even when such a short time is applied, a sintered body having an equal or better quality can be produced.

The molding step may be carried out in a reducing atmosphere. When the forming step is carried out in a reducing atmosphere, the boron carbide powder may be reduced by reducing materials such as boron oxide that may be formed by reacting with oxygen in the air to produce a boron carbide sintered body having a higher boron carbide content.

The forming step may be performed while generating a spark in the gap between the particles in the sintering furnace. In this case, the die may proceed in such a way as to apply electrical energy on a pulse to the die by means of an electrode connected to the pressing unit. In this case, when the forming step is performed while applying the electrical energy of the pulse, the dense sintered body can be obtained in a shorter time by the electrical energy.

The maximum temperature section of the sintering temperature in the molding step may be about 1900 ℃ to about 2200 ℃, it may be maintained for about 2 hours to about 5 hours. In this case, the pressure applied to the die may be about 15 MPa to about 60 MPa. In more detail, the pressure applied to the die may be about 17 MPa to about 30 MPa.

Specifically, when the forming step is carried out in the spark plasma sintering apparatus, the temperature rise in the chamber is progressed, the pressurization is carried out with or separately from the die may be sintered. At this time, the electrical energy applied in the chamber may promote sintering of the raw material, for example, may apply a DC pulse current.

A method of manufacturing a boron carbide sintered body according to another embodiment of the present invention includes a preparation step of preparing a substrate and a gaseous material and a deposition step of depositing the substrate boron carbide layer.

The boron carbide sintered body may be manufactured by a deposition process. For example, the vapor deposition bulk may produce the surface or all of the substrate by vapor deposition such as CVD. Specifically, when the boron carbide sintered body is applied by a CVD method (CVD vapor deposition bulk production method), the boron carbide sintered body is CVD boron carbide (BC) deposition on the substrate, substrate removal, shape processing, polishing, measuring and cleaning It can be prepared including the process of.

The CVD boron carbide deposition process is a process of forming a boron carbide deposited film on a substrate (mainly graphite). The substrate may be removed after the deposition has proceeded sufficiently in such a way that the gaseous material is physically deposited onto the substrate.

The shape processing process is a process of completing the boron carbide sintered body to have a predetermined shape by mechanical processing. Polishing is the process of smoothing the surface finish and then checking the quality and removing contaminants. Some of the above processes may be omitted or other processes may be added within the scope of the present invention.

In the CVD process, boron source gas and carbon source gas may be used as the gaseous material. The boron source gas applied to the CVD process may contain any one selected from the group consisting of B ₂ H ₆ , BCl ₃ , BF _3, and a combination thereof. In addition, the carbon source gas used in the CVD process may contain CF ₄ .

For example, the boron carbide sintered body may be one deposited using a chemical vapor deposition apparatus using B ₂ H ₆ as a boron precursor and a deposition temperature of 500 to 1500 ° C.

In order to form the boron carbide sintered body, various deposition or coating processes may be applied. The method of coating the boron carbide coating layer with a thick film on a substrate or the like is not limited, and there are physical vapor deposition, room temperature spraying, low temperature spraying, aerosol spraying and plasma spraying.

In the physical vapor deposition method, for example, a boron carbide target may be sputtered in an argon (Ar) gas atmosphere. The coating layer formed by the physical vapor deposition method may be referred to as a thick PVD boron carbide coating layer.

In the room temperature spraying method, a boron carbide sintered body layer may be formed by applying pressure to the boron carbide powder at room temperature and spraying the base material through a plurality of discharge ports. In this case, the boron carbide powder may use a vacuum granule form. In the low temperature spraying method, at a temperature higher than about 60 ° C. from room temperature, the boron carbide powder may be sprayed onto the base material through a plurality of discharge ports by the flow of compressed gas to form the boron carbide sintered body in the form of a coating layer. The aerosol injection method is to form aerosol by mixing the boron carbide powder in a volatile solvent such as polyethylene glycol, isopropyl alcohol and the like, and then to form a boron carbide sintered body by spraying the aerosol to the base material. In the plasma spraying method, boron carbide powder is injected into a high temperature plasma jet to spray the powder melted in the plasma jet on a substrate at a high speed to form a boron carbide sintered body.

The boron carbide sintered body thus manufactured has the above-described physical properties, and according to the above method, the boron carbide sintered body having excellent physical properties can be manufactured in a faster time.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples are merely examples to help understanding of the present invention, but the scope of the present invention is not limited thereto.

1. Preparation of the boron carbide sintered body of manufacture examples 1-8

A raw material such as boron carbide particles (particle size, D ₅₀ = 0.7 μm), carbon, and a solvent were placed in a slurry mixer to be mixed in a ball mill manner to prepare a slurryed raw material. The slurryed raw material was spray dried to granulate to prepare a granulated raw material.

Each of the raw materials was filled in a rubber mold, loaded in a CIP device, and pressed to prepare green bodies, respectively. The green body was carbonized to remove contaminants and atmospheric sintering in a sintering furnace to produce sintered bodies of each production example.

2. Preparation of the boron carbide sintered body of manufacture example 9

Boron carbide particles (particle size D ₅₀ = 0.7㎛) was charged to the die, charged in the press molding equipment, and then sintered at the temperature, pressure and time shown in Table 1 to prepare a sintered body of Preparation Example 9.

The content, sintering temperature and time of the raw materials applied to each production example are summarized in Table 1 below.

Preparation # Sintering Characteristics
Improver 1 * (% by weight) Sintering Characteristics
Improver 2 **
(weight%) Boron Carbide Powder (% by weight) Sintering Temperature
(℃) Sintering time
(time) pressure
(Mpa) One 0 0 100 2380 10 Atmospheric pressure 2 5 0 Remaining amount 2380 10 Atmospheric pressure 3 15 0 Remaining amount 2380 10 Atmospheric pressure 4 20 0 Remaining amount 2380 10 Atmospheric pressure 5 20 0 Remaining amount 2380 15 Atmospheric pressure 6 10 0 Remaining amount 2380 15 Atmospheric pressure 7 0 10 Remaining amount 2380 15 Atmospheric pressure 8 10 5 Remaining amount 2380 15 Atmospheric pressure 9 0 0 100 1950 5 25

* Carbon is applied as the first sintering characteristic improvement.

** Boron oxide is applied as the second sintering characteristic improvement.

3. Comparative Example 1 and Comparative Example 2

In Comparative Example 1, SiC produced by CVD was applied. Specifically, SiC of Comparative Example 1 was manufactured by forming a chemical vapor deposition silicon carbide (CVD-SiC) layer having the same component as the base material layer on one side of the silicon carbide base material layer.

In Comparative Example 2, single crystal silicon was applied.

4. Evaluation of Physical Properties

(1) Relative density evaluation and surface observation

Relative density (%) was measured by the Archimedes method. The results are shown in Table 2 below. In addition, the surface characteristics were observed with the electron microscope, and each surface characteristic is shown in the accompanying drawing. "-" Indicates no measurement.

Preparation # Sintering Characteristics
Improver sum Sintering Temperature
(℃) Sintering time
(time) Relative density
(%) Type of Sintering Property Enhancer Surface observation One 0 2380 10 63.77 carbon - 2 5 2380 10 77.38 carbon (A) of FIG. 3 15 2380 10 90.4 carbon (B) of FIG. 4 20 2380 10 90.76 carbon (A) of FIG. 5 20 2380 15 93.11 carbon (B) of FIG. 2 6 10 2380 15 94.14 carbon (A) of FIG. 7 10 2380 15 95.42 Boron oxide (B) of FIG. 8 15 2380 15 97.43 mix - 9 0 1950 5 99.9 Unapplied -

Referring to Table 2, referring to Preparation Examples 1 to 4, when the carbon is applied to the sintering characteristics improving agent, the relative density of the sintered body manufactured under the same conditions increases as the application amount increases to about 20% by weight. Confirmed that. That is, when carbon is applied as a sintering characteristic improving agent, a particularly high relative density can be obtained when the carbon is applied in the range of 12 to 23% by weight.

In addition, when comparing the results of Preparation Examples 5 and 6 with the results of Preparation Examples 1 to 4, it was confirmed that the relative density increases as the sintering time is increased, in this case, rather the case of reducing the application amount of the sintering characteristics improving agent rather than the sintering characteristics It was also confirmed that this could be further improved.

In the case of Preparation Example 9 was pressed and sintered without applying a separate sintering characteristics improving agent, it was possible to obtain a boron carbide sintered body excellent in sintering characteristics.

1 to 3, which observed the surface of the sintered body, it was confirmed that the necking phenomenon increases and the density becomes denser as the relative density increases.

(2) Thermal Conductivity, Resistance and Etch Rate

Thermal conductivity [W / (m * k)] was measured by Laser Flash Apparatus (LFA457).

Resistance characteristic (Ω * cm) was measured with the specific resistance surface resistance measuring instrument (MCP-T610).

The etch rate characteristics (%) were applied under the same temperature and atmosphere by applying RF power of 2000 W to the TEL plasma equipment.

The physical property evaluation results are shown in Tables 3 and 4, respectively.

Preparation # 25 degrees
Thermal conductivity 400 degrees
Thermal conductivity 800 degrees
Thermal conductivity HD25: HD800
ratio Surface observation One - - - - - 2 - - - - (A) of FIG. 3 - - - - (B) of FIG. 4 - - - - - 5 31.665 22.481 16.625 0.525 (A) of FIG. 6 30.269 21.144 15.684 0.518 (B) of FIG. 2 7 - - - - (A) of FIG. 8 - - - - (B) of FIG. 9 23.659 9.419 7.497 0.269 - Comparative Example 1 265.526 116.373 68.312 0.257 - Comparative Example 2 - - - (Calculated value) -

Preparation # Resistance (Resistance, Ωcm) Etching rate
(%) (One) Etching rate
(%) (2) Fluorine ion
Particle Formation Etch rate (1) before and after
Surface observation 5 3.21 * 10 ^-1 86.22 - X Before etching: Figure 4 (a)
After etching: FIG. 4B 6 1.85 * 10 ^-1 - - X - 8 6.832 * 10 ^-1 61.54 40 X Before etching: (a) of FIG.
After etching: FIG. 5B 9 1.706 * 10 ⁰ 59.39 36 X - Comparative Example 1 - 100 62 X - Comparative Example 2 - - 100 X -

Referring to the above experimental results, it was confirmed that the state density characteristics of Preparation Examples 2 to 8 is higher than that of Preparation Example 1, in which the sintering characteristic improving agent was not applied, but relative to the capacity of the same sintering characteristics improving agent. It was found that the density did not increase, and the experimental results showed that the relative density decreased when the 25 wt% carbon was applied as compared with the 20 wt% carbon.

Example 7 in which boron oxide was applied as a sintering characteristic improving agent had a higher relative density than Example 6 in which the same amount of carbon was applied. It had an excellent relative density value compared with Examples 5-7 which applied similarly. In addition, the results of observing the surface characteristics, it was confirmed that the carbon area is evenly spread throughout, so that the relatively large carbon area present in the pores does not appear or the density of generation is significantly reduced.

The samples thus prepared had a range of thermal conductivity characteristics, showed excellent etching rates compared to silicon carbide and silicon, and were evaluated to have excellent corrosion resistance. In particular, in the case of Preparation Example 9, which had a different manufacturing method, the best etching resistance was shown. Among the Preparation Examples 1 to 8 prepared by the similar manufacturing method, Preparation Example 8 showed a very good result. It is considered to be an excellent result compared with SiC and Si.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (10)

Boron carbide-containing particles are necked, and the thermal conductivity measured at 400 ° C. is 27 W / (m * k) or less, and the ratio of the thermal conductivity measured at 25 ° C. and the thermal conductivity measured at 800 ° C. is 1 : Boron carbide sintered compact which is 0.2-3. The method of claim 1,
The particles are boron carbide sintered body having a particle size (D ₅₀ ) of 1.5 um or less. The method of claim 1,
The boron carbide sintered compact whose Ra roughness measured on the surface is 0.1 micrometer-1.2 micrometers. The method of claim 1,
A boron carbide sintered body having a porosity of 3% or less. The method of claim 1,
The boron carbide sintered compact whose average diameter of the pore observed in the surface or a cross section is 5 micrometers or less. The method of claim 1,
The boron carbide sintered compact whose area of the part whose pore diameter observed on the surface or a cross section is 10 micrometers or more is 5% or less. The method of claim 1,
A boron carbide sintered body which does not form particles in contact with fluorine ions or chlorine ions in a plasma etching equipment. The method of claim 1,
A boron carbide sintered body having an etching rate of 55% or less than that of silicon. The method of claim 1,
A boron carbide sintered body having an etching rate of 70% or less compared to CVD-SiC. An etching apparatus comprising at least a part of the boron carbide sintered body according to claim 1.

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