Ceramic susceptor and manufacturing method thereof

Abstract

To provide: a ceramic susceptor which is superior particularly in volumetric resistance at high temperatures and thermal conductivity at room temperature compared to a typical ceramic susceptor; and a method for manufacturing the same.SOLUTION: A ceramic susceptor that is superior particularly in volumetric resistance at high temperatures and thermal conductivity at room temperature compared to a typical ceramic susceptor, and a method for manufacturing the same, are disclosed. The ceramic susceptor contains alumina (Al2O3) and aluminum nitride (AlN) and does not contain any secondary phase including an aluminum oxynitride phase (AlON phase).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ceramic susceptor and a method for manufacturing the same, and more particularly to a ceramic susceptor that is superior in volume resistance at high temperatures and thermal conductivity at room temperature compared to ordinary ceramic susceptors, and a method for manufacturing the same. [Background technology]

[0002] As semiconductor processes become increasingly miniaturized and highly integrated, the use of high-power plasma is inevitable. Therefore, vacuum plasma equipment using high-temperature plasma is widely used in the fields of semiconductor device etching and other processes for achieving ultra-fine shapes. These vacuum plasma equipment include PECVD (plasma enhanced chemical vapor deposition) equipment, which forms deposition films on substrates using plasma-assisted chemical vapor deposition; sputtering equipment, which forms deposition films using physical methods; and dry etching equipment, which etch substrates or materials coated on them into specific patterns.

[0003] However, the high-temperature plasma generated inside a vacuum plasma device can easily damage the chamber and the components installed therein. Furthermore, certain elements and contaminant particles are likely to be generated from the surfaces of the chamber and the components installed therein, contaminating the interior of the chamber. In particular, in the case of a plasma etching device, reactive gases such as F and Cl are injected into the plasma atmosphere, exposing the inner walls and components of the chamber to a highly corrosive environment. This corrosion typically primarily results in chemical and physical damage to the chamber and the components installed therein, and secondarily, generates contaminants and particles, resulting in an increased defect rate and reduced quality of products manufactured through processes inside the chamber.

[0004] If the chamber or the components installed inside it are damaged, the damaged equipment must be replaced, cleaned, or repaired, resulting in additional costs and the process line must be stopped, increasing the processing time required for product manufacturing. For these reasons, the metal susceptors previously installed inside the chamber are being replaced with ceramic susceptors, such as aluminum nitride (AlN) sintered compacts and alumina (Al2O3) sintered compacts, which have excellent thermal conductivity. These ceramic susceptors are mainly used in heaters and electrostatic chucks for semiconductor manufacturing processes.

[0005] Aluminum nitride is stable at high temperatures and has excellent physical properties such as electrical insulation and thermal conductivity. It also has a thermal expansion coefficient similar to that of silicon, so it is mainly used in semiconductor manufacturing equipment, which requires high electrical resistance at high temperatures. Alumina is also stable at high temperatures and has better electrical insulation and higher hardness than aluminum nitride.

[0006] Recently, semiconductor manufacturing processes have been miniaturized and equipment diameters increased to improve yields. However, these miniaturizations and larger-diameter equipment have caused various problems in the semiconductor manufacturing process. Therefore, next-generation semiconductor processing technologies that can overcome these problems are needed. Accordingly, these processes are carried out in harsher environments, at temperatures ranging from 600°C to 700°C. To withstand these environments, ceramic susceptors must meet the following ceramic characteristics: a volume resistivity of 1.0E+10 Ω·cm to 1.0E+13 Ω·cm at 500°C and a thermal conductivity of 30 W / mk or higher, preferably 40 W / mk or higher, at room temperature.

[0007] However, aluminum nitride suffers from a tendency to generate leakage current due to a sudden drop in volume resistivity at 500°C, while alumina has a very low thermal conductivity of 20W / mK to 30W / mK at room temperature. If the thermal conductivity at room temperature is only 20W / mK to 30W / mK, temperature uniformity deviations become significant, resulting in problems such as reduced yields. Furthermore, large deviations in temperature uniformity in thermal conductivity can result in a shortened product lifespan due to thermal stress and thermal shock. Therefore, to prevent leakage current even at temperatures above 500°C, a ceramic susceptor is required that has both high volume resistivity and high thermal conductivity at room temperature. Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a ceramic susceptor which is superior in volume resistance at high temperatures and thermal conductivity at room temperature compared to ordinary ceramic susceptors, and a method for producing the same. [Means for solving the problem]

[0009] To achieve the above object, the present invention provides a ceramic susceptor that includes alumina (Al2O3) and aluminum nitride (AlN), and does not include any secondary phase, including an aluminum oxynitride phase (AlON phase).

[0010] The present invention also provides a ceramic susceptor comprising alumina (Al2O3); and a dopant, wherein the dopant comprises at least one of magnesium oxide (MgO), yttria (Y2O3), graphene, and a rare earth composite oxide.

[0011] The present invention also provides a method for manufacturing a ceramic susceptor, including: a) mixing alumina (Al2O3), aluminum nitride (AlN), an alcohol compound, and a binder; b) drying the mixture to prepare a powder from which the alcohol compound component has been removed; c) compressing and molding the dried powder to prepare a preform processed into a predetermined shape; d) degreasing the prepared preform to remove the binder component; and e) sintering and polishing the degreasing preform.

[0012] The present invention also provides a method for manufacturing a ceramic susceptor, the method comprising: a) mixing alumina (Al2O3), a dopant, an alcohol compound, and a binder; b) drying the mixture to prepare a powder from which the alcohol compound component has been removed; c) compressing and molding the dried powder to prepare a preform processed into a predetermined shape; d) degreasing the prepared preform to remove the binder component; and e) sintering and polishing the degreasing preform; wherein the dopant comprises one or more of magnesium oxide (MgO), yttria (Y2O3), graphene, and a rare earth composite oxide. [Effects of the Invention]

[0013] The ceramic susceptor and the method for producing the same according to the present invention have advantages over conventional ceramic susceptors, particularly in that they have superior volume resistance at high temperatures and thermal conductivity at room temperature. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an XRD graph showing the physical property values ​​of a ceramic susceptor depending on the sintering temperature. [Figure 2] 1 is a graph showing the correlation between alumina content and sintering temperature. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described in detail below.

[0016] A ceramic susceptor according to one embodiment of the present invention (first embodiment) is characterized in that it contains alumina (Al2O3) and aluminum nitride (AlN) and does not contain any secondary phase including an aluminum oxynitride phase (AlON phase).

[0017] As semiconductor processes become increasingly miniaturized and highly integrated, the use of high-power plasma is unavoidable. Accordingly, vacuum plasma equipment using high-temperature plasma is widely used to etch semiconductor devices or achieve other ultra-fine features. For this reason, the industry is increasingly using ceramic susceptors made of aluminum nitride (AlN) sintered bodies or alumina (Al2O3) sintered bodies, which have superior plasma corrosion resistance, instead of conventional metal susceptors. Recently, semiconductor manufacturing processes have become more demanding, requiring process miniaturization and larger equipment diameters to improve yields. To withstand these conditions, ceramic susceptors must meet the following ceramic characteristics: a volume resistivity of 1.0E+10 Ω·cm to 1.0E+13 Ω·cm at 500°C and a thermal conductivity of 30 W / mk or higher, preferably 40 W / mk or higher, at room temperature.

[0018] However, aluminum nitride suffers from a tendency for leakage current to occur due to a rapid drop in volume resistivity at 500°C, while alumina has a very low thermal conductivity of 20-30 W / mK at room temperature. If the thermal conductivity at room temperature is only 20-30 W / mK, temperature uniformity deviations become significant, resulting in problems such as reduced yield. Furthermore, large deviations in temperature uniformity in thermal conductivity can result in a shortened product life due to thermal stress and thermal shock. Therefore, after extensive research, the present applicant has invented a ceramic susceptor that can be used at temperatures above 500°C. This ceramic susceptor has high volume resistivity at temperatures above 500°C, preventing leakage current, and has higher thermal conductivity at room temperature than conventional ceramic susceptors, thereby resolving the above-mentioned problems.

[0019] The ceramic susceptor according to the first embodiment of the present invention is a sintered body containing, as a main phase, alumina (Al2O3), which has excellent electrical insulation and high hardness as well as stability at high temperatures, and aluminum nitride (AlN), which is stable at high temperatures and has excellent physical properties such as electrical insulation and thermal conductivity.

[0020] In particular, the present invention is characterized by the fact that by mixing alumina and aluminum nitride in an optimal ratio, it overcomes both the problems that arise when alumina and aluminum nitride are used separately and the problems that arise when alumina and aluminum nitride are not mixed in the optimal ratio. Specifically, when alumina and aluminum nitride are mixed in the optimal ratio as in the present invention, secondary phases such as AlON phase are not formed (i.e., secondary phases containing AlON phase are not present), as shown in Table 5 below, and the alumina phase and aluminum nitride phase are uniformly mixed and distributed without any change in the crystalline phase, thereby maximizing the physical properties of the ceramic susceptor. Furthermore, by performing the sintering process in the ceramic susceptor manufacturing process at an optimal temperature (less than 1,650°C, preferably between 1,300°C and 1,650°C), the formation of secondary phases can be more thoroughly prevented. Accordingly, the ceramic susceptor satisfies the ceramic characteristics of having a volume resistivity of 1.0E+10 Ω·cm to 1.0E+13 Ω·cm at 500°C and a thermal conductivity of 30 W / mk or more at room temperature.

[0021] The ceramic susceptor according to the first embodiment of the present invention contains more than 68 wt% and less than 99.8 wt%, preferably 70 wt% to 95 wt%, more preferably 70 wt% to 80 wt%, and most preferably 73 wt% to 77 wt% alumina. The ceramic susceptor according to the first embodiment of the present invention also contains more than 0.2 wt% and less than 32 wt%, preferably 5 wt% to 30 wt%, more preferably 20 wt% to 30 wt%, and most preferably 23 wt% to 27 wt% aluminum nitride. If the alumina and aluminum nitride contents do not fall within the above ranges, the volume resistivity at 500°C and the thermal conductivity at room temperature will not meet the required ceramic properties. Therefore, the ceramic susceptor will not have a volume resistivity of 1.0E+10 Ω·cm to 1.0E+13 Ω·cm at 500°C and a thermal conductivity of 30 W / mK or more at room temperature.

[0022] The purity of the alumina and aluminum nitride is preferably 99% or more, the particles thereof are preferably nano-sized, and both are preferably used in the form of powder.

[0023] More specifically, the alumina particles may have a nanometer to micrometer size. For example, the alumina particles may be obtained by mixing 3 μm to 5 μm-sized alumina particles and 50 nm-sized alumina particles in a weight ratio of about 7:3, followed by pulverization using a ball mill. However, the particle size and mixing ratio vary widely, and the ball mill process may be omitted, so the present invention is not limited to the above example.

[0024] The aluminum nitride particles may have an average particle size (D50) of 0.5 μm to 1.5 μm, preferably 0.8 μm to 1.3 μm, and more preferably 0.9 μm to 1.2 μm. If the aluminum nitride particles have an average particle size (D50) of less than 0.5 μm, the reaction temperature may be low, which may result in a reaction with alumina at a low temperature to form a secondary phase. If the aluminum nitride particles have an average particle size (D50) of more than 1.5 μm, a close-packed / packed structure with alumina may not be formed, resulting in a decrease in density during final sintering. Furthermore, in the present invention, it is preferable to avoid nanometer-sized aluminum nitride particles as much as possible.

[0025] Meanwhile, the ceramic susceptor according to the first embodiment may further include a dopant, if necessary, for the purpose of further improving the thermal conductivity of the ceramic susceptor.

[0026] For example, if a regular sintered body is applied to a substrate and a ceramic heater or electrostatic chuck for semiconductors is used at temperatures above 500°C, the substrate may not be able to keep up with the sudden temperature change of the heating element, resulting in fracture due to thermal shock. However, if a dopant is mixed into the substrate to improve its thermal shock resistance and it is used in a heater or electrostatic chuck, the heat from the heating element can be transferred efficiently, preventing fracture of the substrate due to thermal shock.

[0027] The dopant of the present invention may be, for example, one or more of magnesium oxide (MgO), yttria (Y2O3), graphene, and rare earth composite oxides.

[0028] When the ceramic susceptor further contains a dopant, the dopant may be contained in an amount of 0.05 to 2 parts by weight, preferably 0.1 to 1 part by weight, and more preferably 0.2 to 0.8 parts by weight, based on 100 parts by weight of the total weight of the alumina and aluminum nitride. If the dopant is contained in an amount less than 0.05 parts by weight based on 100 parts by weight of the total weight of the alumina and aluminum nitride, or if the dopant is not contained at all, the same problems as those previously observed may occur, or the effect of using the dopant may be significantly reduced, resulting in a negligible improvement in thermal conductivity and a problem of non-sintering. Furthermore, if the dopant content exceeds 2 parts by weight based on 100 parts by weight of the total weight of the alumina and aluminum nitride, the dispersion effect may be reduced, resulting in a decrease in thermal conductivity and a decrease in sintering density. Furthermore, the dopant may cause the product to darken in color or the color of the dopant to be retained. Furthermore, it is preferable that all dopants used in the present invention have a purity of 99% or higher. The dopants are preferably contained in an amount of 0.05% by weight to 0.5% by weight.

[0029] Magnesium oxide, one of the dopants, may be included to improve the thermal conductivity and volume resistivity of the ceramic susceptor. Magnesium oxide may induce the formation of MgAl2O4 or MgAlON phases through sintering with the alumina and / or aluminum nitride. However, excessive formation of MgAl2O4 or MgAlON phases can result in a decrease in density and even thermal conductivity. Therefore, even when the same components are used, it is necessary to adjust the content of each component. For example, in the present invention, the final ceramic susceptor may contain at least one of the MgAl2O4 and MgAlON phases in an amount of less than 1 wt %, preferably less than 0.8 wt %, and more preferably 0.6 wt % or less, based on the total weight of the ceramic susceptor. The particle size of the magnesium oxide is not particularly limited, but nanometer-sized particles, which may have a relatively weak effect, are preferably excluded.

[0030] The yttria (YO) may be included to improve the thermal conductivity of the ceramic susceptor. The purity of the yttria is preferably 99% or higher. To improve physical properties through densification, the yttria particles are preferably nanosized, and such yttria is preferably used in the form of powder. More specifically, the average particle size (D50) of the yttria particles may be 50 nm to 150 nm, preferably 70 nm to 120 nm, and more preferably 90 nm to 100 nm. If the average particle size (D50) of the yttria particles is less than 50 nm, even a trace amount may result in a sintered body that retains the color (e.g., yellow) of the yttria particles due to the characteristics of nano-yttria powder. Furthermore, if the average particle size (D50) of the yttria particles exceeds 150 nm, an incomplete sintered body may be formed during sintering, resulting in a decrease in density and a decrease in thermal conductivity. In particular, when the average particle size (D50) of the yttria particles is on the order of micrometers, this problem may become more pronounced.

[0031] Graphene may also be included to improve the thermal conductivity of the ceramic susceptor. The purity of the graphene is preferably 99% or higher, and the graphene particles are nano-sized. Such graphene is preferably used in the form of powder (Graphene nano powder, GNP). More specifically, the average particle size (D50) of the graphene particles may be 0.1 nm to 1.5 nm, preferably 0.3 nm to 1 nm, and more preferably 0.5 nm to 0.8 nm. If the average particle size (D50) of the graphene particles is less than 0.1 nm, the graphene particles may not be large enough to function as bridges between graphene particles, resulting in little or no effect on improving thermal conductivity. Furthermore, if the average particle size (D50) of the graphene particles exceeds 1.5 nm, the graphene particles may become entangled with each other, resulting in poor dispersion, which may result in a decrease in density and a decrease in thermal conductivity.

[0032] Finally, the rare earth composite oxide contains two or more rare earth metals selected from the group consisting of scandium (Sc), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (YB), and lutetium (Lu). The purity of the rare earth composite oxide containing such rare earth metals is preferably 99% or higher. The rare earth composite oxide is preferably in the form of a powder, and the size of the powder particles is not particularly limited.

[0033] The rare earth composite oxide may further improve the thermal conductivity of the ceramic susceptor, and the use of the rare earth composite oxide may shorten the time required for dechucking. As described above, the rare earth composite oxide may contain two or more rare earth metals, preferably two to five different rare earth metals.

[0034] The rare earth composite oxide containing two to five different rare earth metals includes europium-gadolinium composite oxide (EuGdO X ), samarium-gadolinium composite oxide (SmGdO X ), cerium-europium composite oxide (CeEuO X ), samarium-cerium composite oxide (SmCeO X ), gadolinium-samarium composite oxide (GdSmO X ), lanthanum-cerium composite oxide (LaCeO X ), a composite oxide containing two different rare earth metals; samarium-cerium-europium composite oxide (SmCeEuO X ), gadolinium-cerium-lanthanum composite oxide (GdCeLaO X ), europium-gadolinium-samarium composite oxide (EuGdSmO X ), a composite oxide containing three different rare earth metals; samarium-cerium-gadolinium-europium composite oxide (SmCeGdEuO X ) and gadolinium-samarium-europium-lanthanum composite oxide (GdSmEuLaO X ), a composite oxide containing four different rare earth metals; and samarium-cerium-europium-gadolinium-gadolinium-lanthanum composite oxide (SmCeEuGdLaO X ) and other composite oxides containing two to five different rare earth metals (oxides) can be used without any particular restrictions as long as they contain two to five different rare earth metals (oxides).

[0035] The rare earth composite oxide containing two to five different rare earth metals may contain the various rare earth metals in various ratios. For example, the rare earth composite oxide containing two to five different rare earth metals may contain two rare earth metals (oxides) in a weight ratio of 2.5 to 3.5:1, three rare earth metals (oxides) in a weight ratio of 1 to 3.5:0.5 to 2.5:1, four rare earth metals (oxides) in a weight ratio of 1.5 to 3.5:0.5 to 2.5:1 to 2.5:1, or five rare earth metals (oxides) in a weight ratio of 1 to 3:0.5 to 1.5:0.5 to 1.5:0.5 to 1.5:1 to 2:1. The rare earth metals (oxides) can be appropriately blended to maximize the desired effect of the rare earth composite oxide. For example, SmCeEuO X The ratio of each rare earth metal (oxide) is 2:1:1:1, GdCeLaO X is 3:2:1, EuGdSmO X is 1.5:1.5:1, SmCeGdEuO X is 2:1:1.5:1, GdSmEuLaO X is 3:2:2:2:1, SmCeEuGdLaO X may be in a weight ratio of 2:1:1:1.5:1.

[0036] In the rare earth composite oxide, one rare earth metal may be dissolved in the remaining one (or any one) rare earth metal oxide. This changes the crystal structure of the rare earth metal oxide, and therefore the rare earth composite oxide may have more oxygen lattice defects than a single rare earth metal oxide. A rare earth composite oxide with increased oxygen lattice defects has improved interfacial reactivity, which may allow it to react effectively with the interface or lattice oxygen of components in a ceramic susceptor.

[0037] Furthermore, rare earth metal oxides containing one rare earth metal include scandium oxide (Sc2O3), lanthanum oxide (La2O3), cerium oxide (CeO2), and praseodymium oxide (Pr6O 11), neodymium oxide (Nd2O3), promethium oxide (Pm2O3), samarium oxide (Sm2O3), europium oxide (Eu2O3), gadolinium oxide (Gd2O3), terbium oxide (Tb4O7), dysprosium oxide (Dy2O3), holmium oxide (Ho2O3), erbium oxide (Er2O3), thulium oxide (Tm2O3), ytterbium oxide (YB2O3), and lutetium oxide (Lu2O3), however, the present invention does not include rare earth metal oxides that contain only one rare earth metal as a dopant.

[0038] Meanwhile, in the above description, the dopant includes one or more of magnesium oxide, yttria, graphene, and rare earth metal oxides other than yttria. However, in the present invention, it is preferable that the dopant primarily includes magnesium oxide. It is also preferable that magnesium oxide and graphene are used in combination as the dopant. It is even more preferable that magnesium oxide, graphene, and yttria are used in combination as the dopant. It is most preferable that magnesium oxide, graphene, yttria, and a rare earth composite oxide are used in combination as the dopant.

[0039] When magnesium oxide and graphene are used together as dopants, the magnesium oxide may be contained in an amount of 0.05 parts by weight to 0.5 parts by weight, and the graphene may be contained in an amount of 0.05 parts by weight to 0.5 parts by weight, relative to 100 parts by weight of the total weight of the alumina and aluminum nitride.

[0040] Furthermore, when magnesium oxide, graphene, and yttria are used in combination as dopants, the magnesium oxide may be contained in an amount of 0.05 to 0.5 parts by weight, the graphene may be contained in an amount of 0.05 to 0.5 parts by weight, and the yttria may be contained in an amount of 0.05 to 0.5 parts by weight, relative to 100 parts by weight of the total weight of the alumina and aluminum nitride.

[0041] Furthermore, when magnesium oxide, graphene, yttria, and a rare earth composite oxide are used in combination as dopants, the magnesium oxide may be contained in an amount of 0.05 to 0.5 parts by weight, the graphene may be contained in an amount of 0.05 to 0.5 parts by weight, the yttria may be contained in an amount of 0.05 to 0.5 parts by weight, and the rare earth composite oxide may be contained in an amount of 0.05 to 0.5 parts by weight, relative to 100 parts by weight of the total weight of the alumina and aluminum nitride.

[0042] Next, a ceramic susceptor according to a second embodiment of the present invention will be described. The ceramic susceptor according to the second embodiment of the present invention includes alumina (Al2O3) and a dopant, and the dopant includes one or more of magnesium oxide (MgO), yttria (Y2O3), graphene, and rare earth composite oxide.

[0043] *43 The applicant has confirmed that the ceramic susceptor according to the second embodiment also has excellent volume resistance and thermal conductivity in addition to the ceramic susceptor according to the first embodiment. The ceramic susceptor according to the second embodiment will be described in detail below.

[0044] The ceramic susceptor according to the second embodiment has a configuration in which only aluminum nitride is removed from the ceramic susceptor according to the first embodiment, which also includes a dopant. The alumina is contained in an amount remaining after subtracting the total content of the dopant. Specifically, the dopant may be contained in an amount of 0.05 wt% to 2 wt%, preferably 1 wt% to 2 wt%, and more preferably 1.5 wt% to 2 wt%, based on the total weight of the ceramic susceptor. The alumina may be contained in an amount of 98 wt% to 99.95 wt%, preferably 98 wt% to 99 wt%, and more preferably 98 wt% to 98.5 wt%, based on the total weight of the ceramic susceptor. If the alumina and dopant are not contained within the above content ranges, the volume resistivity and thermal conductivity characteristics desired by the present invention will not be achieved.

[0045] Preferably, the dopants used herein also have a purity of 99% or higher. Preferably, each dopant is contained in an amount of 0.05% to 0.5% by weight. Meanwhile, when the ceramic susceptor according to the second embodiment contains magnesium oxide (MgO) as a dopant, the sintering reaction between alumina and magnesium oxide may cause the formation of an MgAl2O4 spinel phase. If the MgAl2O4 spinel phase is excessively generated, the thermal conductivity may decrease. Therefore, even if the same components are used, it is necessary to adjust the content of each component.

[0046] Meanwhile, in the above description, the dopant is described as including one or more of magnesium oxide, yttria, graphene, and rare earth metal oxides other than yttria. However, similar to the first embodiment, the ceramic susceptor according to the second embodiment preferably includes magnesium oxide as the dopant. It is preferable to use magnesium oxide and graphene in combination as the dopant. It is even more preferable to use magnesium oxide, graphene, and yttria in combination as the dopant. It is most preferable to use magnesium oxide, graphene, yttria, and a rare earth composite oxide in combination as the dopant.

[0047] When magnesium oxide and graphene are used together as dopants, the magnesium oxide may be contained in an amount of 0.05 wt % to 0.5 wt %, and the graphene may be contained in an amount of 0.05 wt % to 0.5 wt %.

[0048] Furthermore, when magnesium oxide, yttria, and graphene are used in combination as dopants, the magnesium oxide may be contained in an amount of 0.05% by weight to 0.5% by weight, the yttria may be contained in an amount of 0.05% by weight to 0.5% by weight, and the graphene may be contained in an amount of 0.05% by weight to 0.5% by weight.

[0049] In particular, when magnesium oxide, yttria, graphene, and a rare earth composite oxide are used in combination as dopants, the magnesium oxide may be contained in an amount of 0.05% by weight to 0.5% by weight, the yttria may be contained in an amount of 0.05% by weight to 0.5% by weight, the graphene may be contained in an amount of 0.05% by weight to 0.5% by weight, and the rare earth composite oxide may be contained in an amount of 0.05% by weight to 0.5% by weight.

[0050] The ceramic susceptor according to the present invention has a volume resistivity of 1.0E+10 Ω·cm to 1.0E+13 Ω·cm at 500°C and a thermal conductivity of 30 W / (m·K) (K is Kelvin) Above 40W, preferably 40W / (m·K) ~60W / (m·K) (K is Kelvin) In other words, unless the ceramic heater simultaneously satisfies both the volume resistivity at 500°C and the thermal conductivity at room temperature, the object of the present invention cannot be achieved.

[0051] If the volume resistivity is not satisfied, it will be difficult to apply the ceramic receptor to the next-generation semiconductor manufacturing process, and even if it is applied, there will be a problem of a sudden increase in leakage current. Also, if the thermal conductivity is not satisfied, there will be a problem of a large deviation in temperature uniformity, which will result in a decrease in yield, and it will result in a shortened product life due to thermal stress and thermal shock.

[0052] Next, a method for producing a ceramic susceptor according to the present invention will be described.

[0053] First, the method for manufacturing a ceramic susceptor according to the first embodiment includes the steps of: a) mixing alumina (Al2O3), aluminum nitride (AlN), an alcohol compound, and a binder; b) drying the mixture to prepare a powder from which the alcohol compound component has been removed; c) compressing and molding the dried powder to prepare a preform processed into a predetermined shape; d) degreasing the prepared preform to remove the binder component; and e) sintering and polishing the degreasing preform.

[0054] If necessary, a dopant may be added and mixed in step a), and examples of the dopant include one or more of magnesium oxide (MgO), yttria (Y2O3), graphene, and rare earth composite oxides.

[0055] The alcohol compound used in step a) is used for proper mixing of the raw materials, and examples thereof include alcohol compounds having 1 to 5 carbon atoms, specifically ethanol, methanol, isopropyl alcohol, etc. Similarly, the binder used in step a) is used to improve the binding strength of the raw materials, and examples thereof include polyvinyl alcohol (PVA), polyvinyl butyral (PVB), etc.

[0056] Step b) is a step of drying the powder mixture mixed in step a) to remove the alcohol component. The drying may be performed by a method known in the art, such as spray drying or vacuum drying, and the drying time may vary depending on the physical properties of the intended ceramic susceptor.

[0057] Step c) is a step of compressing the dried powder to produce a preform processed into a specific shape. The compression molding is an initial (i.e., first) molding process for controlling the powder dried in step b) to a desired size and shape, and examples thereof include press molding. Here, cold isostatic pressing (CIP) can be additionally performed as needed to produce a product with a more precise specification. The press molding is preferably performed at room temperature and under normal atmospheric conditions, but is not limited thereto. The atmosphere during molding may be any as long as it does not affect the shaping of the mixture. After the molding process in step c), a preform can be produced by green processing (also known as green processing, as it is performed before sintering).

[0058] Step d) is a step of degreasing the prepared preform to remove binder components. The degreasing is a process for removing binders and oily contaminants, and can be performed at a temperature of 350 to 600°C for 60 hours or less.

[0059] Step e) is a step of sintering (secondary shaping) and polishing the degreased preform to produce a ceramic substrate. The sintering is a second shaping (i.e., secondary shaping) process to further improve the volume resistivity of the ceramic susceptor, and is preferably performed using a hot press sintering method. Furthermore, if the degreased preform is sintered at a temperature of 1,650°C or higher, alumina and aluminum nitride react to form an AlON phase, which reduces thermal conductivity. Therefore, the sintering in step e) must be performed at a temperature below 1,650°C, preferably between 1,300°C and 1,650°C.

[0060] In addition, a method for manufacturing a ceramic susceptor according to a second embodiment includes the steps of: a) mixing alumina (Al2O3), a dopant, an alcohol compound, and a binder; b) drying the mixture to prepare a powder from which the alcohol compound component has been removed; c) compressing and molding the dried powder to prepare a preform processed into a predetermined shape; d) degreasing the prepared preform to remove the binder component; and e) sintering and polishing the degreasing preform, wherein the dopant includes one or more of magnesium oxide (MgO), yttria (Y2O3), graphene, and rare earth composite oxide.

[0061] The ceramic susceptor of the present invention manufactured by the above manufacturing method can be applied to various devices or components for semiconductor manufacturing processes, and is preferably used as a material for heaters and electrostatic chucks for semiconductor manufacturing processes. However, there is no particular limitation on the field of application, and it can also be used in fields where ceramic materials are used in high-temperature plasma environments. The present invention will be described in more detail below with reference to specific examples. The following examples are provided to illustrate the present invention, but the present invention is not limited to the following examples.

[0062] [Examples 1 to 8, Comparative Examples 1 to 8] Production of ceramic susceptors The raw materials were mixed according to the composition in Table 1 below, and then a small amount of ethanol and polyvinyl butyral (binder) was added and dried. The dried mixture was then press-molded and processed to produce a preform, which was then degreased at a temperature of 500°C for 30 hours. The degreased preform was then sintered in a high-temperature pressure sintering furnace (at a pressure of 250 bar and a temperature of 1,630°C) and polished to produce a ceramic susceptor.

[0063] [Table 1] *Dopant unit: weight % *Rare earth composite oxide: Ceria-doped Samarium (Ceria-doped Samarium, CDS)

[0064] [Experimental Example 1] Evaluation of volume resistance and thermal conductivity of ceramic susceptor (1) A voltage of 500 V / mm was applied to each of the ceramic susceptors manufactured in Examples 1 to 8 and Comparative Examples 1 to 8, and then the current was measured (measured in a vacuum atmosphere and at room temperature) after 1 minute to calculate the volume resistivity. The results are shown in Table 2 below.

[0065] In addition, test specimens were prepared from each of the ceramic susceptors manufactured in Examples 1 to 8 and Comparative Examples 1 to 8 according to the standard ASTM C0408-88R11 using a NETZSCH LFA 467 device, and the thermal conductivity was calculated by measuring the test specimens at room temperature. The results are also shown in Table 2 below.

[0066] Furthermore, the density of each of the ceramic susceptors manufactured in Examples 1 to 8 and Comparative Examples 1 to 8 was calculated using Archimedes' method, and the results are also shown in Table 2 below.

[0067] [Table 2]

[0068] The volume resistivity and thermal conductivity of each of the ceramic sensor sensors manufactured in Examples 1 to 8 and Comparative Examples 1 to 8 were measured. As a result, as shown in Table 2, all of the ceramic sensor sensors of Examples 1 to 8 satisfied the volume resistivity at 500°C (1.0E+10 Ω·cm to 1.0E+13 Ω·cm) required by the next-generation semiconductor manufacturing process.

[0069] In addition, in terms of thermal conductivity, as can be seen from the comparison of Examples 1 and 2 with Comparative Examples 1 and 2, the comparison of Examples 3 and 4 with Comparative Examples 3 and 4, the comparison of Examples 5 and 6 with Comparative Examples 5 and 6, and the comparison of Examples 7 and 8 with Comparative Examples 7 and 8, Examples 1 to 8, in which each dopant was used in a content of 0.05 wt% to 0.5 wt%, were superior to Comparative Examples 1 to 8, in which even one dopant was used in an amount exceeding 0.05 wt% to 0.5 wt%.

[0070] In particular, in Examples 7 and 8, in which all dopants were used in amounts of 0.05 wt % to 0.5 wt %, the thermal conductivity at room temperature exceeded 40 W / mk.

[0071] Furthermore, comparing Example 2 and Comparative Example 2, Example 2 used 0.5 wt% MgO, while Comparative Example 2 used 1 wt% MgO, so the difference in content was not significant. However, as the MgO content increased from 0.5 wt% to 1 wt%, the thermal conductivity dropped sharply. This is because when the MgO content exceeds 0.5 wt%, the MgAl2O4 phase or MgAlON phase is formed in excess of 0.6 wt% in the final product, increasing its fraction. These results can be seen in Table 3 below.

[0072] [Table 3] *Dopant unit: weight %

[0073] [Production Examples 1 to 7] Production of ceramic susceptors and evaluation of their properties In order to find the optimum mixing ratio of alumina and aluminum nitride, a ceramic susceptor containing only alumina and aluminum nitride in the same ratio as in Table 4 below was manufactured (other than the composition, the manufacturing method was the same as in Example 1).

[0074] The volume resistivity and thermal conductivity of each of the produced ceramic susceptors were measured, and the results are shown in Table 5 below (the experimental conditions were the same as in Experimental Example 1).

[0075] [Table 4]

[0076] [Table 5] *Al2O3 and AlN units: wt%.

[0077] As can be seen from Tables 4 and 5, the ratio of the aluminum nitride phase varies depending on the ratio of aluminum nitride added, and accordingly, the volume resistivity at high temperature and the thermal conductivity at room temperature vary.

[0078] More specifically, the changes in physical properties depending on the ratio of aluminum nitride added were confirmed, and the results of XRD showed that no AlON phase was formed in any of the final products of Production Examples 1 to 7. Furthermore, both volume resistivity and thermal conductivity were good in Production Examples 3 to 5, with Production Example 5, in which alumina and aluminum nitride were mixed in a weight ratio of 75:25, being the best overall.

[0079] Therefore, if the aluminum nitride content is too low, an Al2O3 phase is formed as the main phase, and there is almost no effect in improving thermal conductivity, while if the aluminum nitride content is too high, the proportion of the AlN phase increases, and although there is an effect in improving thermal conductivity, there is a tendency for volume resistivity and hardness to decrease.

[0080] [Manufacturing Examples 5-1 to 5-5] Evaluation of the physical properties of ceramic susceptors depending on the sintering temperature Based on the results that Preparation Example 5, in which alumina and aluminum nitride were mixed in a weight ratio of 75:25, was the best overall, ceramic susceptors were manufactured by varying only the sintering temperature as shown in Table 6 below (the manufacturing method was the same as that of Example 1 except for the composition and sintering temperature).

[0081] The volume resistivity and thermal conductivity of each of the produced ceramic susceptors were measured, and the results are shown in Table 7 below (the experimental conditions were the same as in Experimental Example 1).

[0082] [Table 6]

[0083] [Table 7] *Units of Al2O3, AlN and AlON: weight %

[0084] Alumina reacts with aluminum nitride above a certain temperature to form an AlON phase. The AlON phase has high electrical insulation but low thermal conductivity, so the presence or absence of the AlON phase significantly affects physical properties. Figure 1 is an XRD graph showing the physical properties of ceramic susceptors as a function of sintering temperature, and Figure 2 is a graph showing the correlation between alumina content and sintering temperature. Referring to Figures 1 and 2 and Table 1, at a sintering temperature of 1,500°C, undersintering occurred, making it impossible to measure volume resistance, and the measured thermal conductivity and density were very low. Analysis of the XRD graphs showed that an AlON phase was formed at sintering temperatures above 1,650°C. As the AlON content increased, the volume resistance increased, but the thermal conductivity decreased sharply. Therefore, it is recommended that sintering be performed at temperatures below 1,650°C.

[0085] [Examples 9 to 20, Comparative Examples 9 to 20] Production of ceramic susceptor Considering the experimental results of Preparation Example 5-3, raw materials were mixed according to the composition in Table 8 below, and trace amounts of ethanol and polyvinyl butyral (binder) were further mixed and dried. The dried mixture was then press-molded and processed to prepare a preform, which was then degreased at a temperature of 500°C for 30 hours. The degreased preform was then sintered in a high-temperature pressure sintering furnace (pressure of 250 bar, temperature of 1,630°C) and polished to prepare a ceramic susceptor.

[0086] [Table 8] *Dopant unit: weight %

[0087] [Experimental Example 2] Evaluation of volume resistance and thermal conductivity of ceramic susceptor (2) A voltage of 500 V / mm was applied to each of the ceramic susceptors manufactured in Examples 9 to 20 and Comparative Examples 9 to 20, and the current was measured after 1 minute (measured in a vacuum atmosphere and at room temperature) to calculate the volume resistivity. The results are shown in Table 9 below.

[0088] In addition, test specimens were prepared from each of the ceramic susceptors manufactured in Examples 9 to 20 and Comparative Examples 9 to 20 according to the standard ASTM C0408-88R11 using a NETZSCH LFA 467 device, and the thermal conductivity was calculated by measuring the test specimens at room temperature. The results are also shown in Table 9 below.

[0089] Furthermore, the density of each of the ceramic susceptors manufactured in Examples 9 to 20 and Comparative Examples 9 to 20 was calculated using Archimedes' method, and the results are also shown in Table 9 below.

[0090] [Table 9]

[0091] The volume resistivity and thermal conductivity of each of the ceramic sensor sensors manufactured in Examples 9 to 20 and Comparative Examples 9 to 20 were measured. As a result, as shown in Table 9, all of the ceramic sensor sensors manufactured in Examples 9 to 20 satisfied the volume resistivity at 500°C (1.0E+10 Ω·cm to 1.0E+13 Ω·cm) required by the next-generation semiconductor manufacturing process.

[0092] In addition, in terms of thermal conductivity, as can be seen from the comparisons of Examples 9 to 11 and Comparative Examples 9 to 11, Examples 12 to 14 and Comparative Examples 12 to 14, Examples 15 to 17 and Comparative Examples 15 to 17, and Examples 18 to 20 and Comparative Examples 18 to 20, in which each dopant was used in a content of 0.05 wt% to 0.5 wt%, it was superior to Comparative Examples 9 to 20 in which even one dopant was used in an amount exceeding 0.05 wt% to 0.5 wt%.

[0093] On the other hand, when graphene nanopowder (GNP) was added as a dopant in addition to MgO, the effect was negligible when the GNP content was less than 0.05 wt%, but the thermal conductivity improved when the GNP content was 0.05 wt% to 0.5 wt%. However, when the GNP content exceeded 0.5 wt%, the volume resistivity, density, and hardness tended to decrease sharply.

[0094] In addition, when nano-sized yttria (Y2O3) was added as a dopant in addition to MgO and GNPs at a concentration of 0.05 to 0.5 wt%, it showed the effect of improving sinterability and increasing volume resistance and thermal conductivity. However, when yttria was used at a concentration exceeding 0.5 wt%, it reacted with alumina to form large amounts of secondary phases such as YAP, YAM, and YAG, which tended to reduce thermal conductivity.

[0095] Furthermore, when rare earth composite oxides were added as dopants in addition to MgO, GNP, and NanoY2O3, when used at 0.05 wt% to 0.5 wt%, not only did the volume resistivity and thermal conductivity tend to increase, but it was also confirmed that the density and hardness also increased. On the other hand, when the rare earth composite oxide was used at a content exceeding 0.5 wt%, both the volume resistivity and thermal conductivity tended to decrease sharply.

[0096] Furthermore, comparing Example 11 and Comparative Example 10, Example 11 used 0.5 wt% MgO, while Comparative Example 10 used 1 wt% MgO, so the difference in content was not significant. However, as the MgO content increased from 0.5 wt% to 1 wt%, the thermal conductivity dropped sharply. This is because when the MgO content exceeds 0.5 wt%, the MgAl2O4 phase or MgAlON phase is formed in excess of 0.6 wt% in the final product, increasing its fraction. These results can be seen in Table 10 below.

[0097] [Table 10] *Dopant unit: weight %

Claims

1. Alumina (Al 2 O 3 ) and aluminum nitride (AlN); In a ceramic susceptor that does not contain a secondary phase containing an aluminum oxynitride phase (AlON phase), The alumina content is more than 68% by weight and less than 95% by weight, and the aluminum nitride content is more than 5% by weight and less than 32% by weight, The ceramic susceptor has a volume resistivity of 1.0E+10 Ω cm to 1.0E+13 Ω cm at 500°C and a thermal conductivity of 30 to 60 W / (m K) (K is Kelvin) at room temperature. Ceramic susceptor.

2. The ceramic susceptor is made of magnesium oxide (MgO), yttria (Y 2 O 3 2. The ceramic susceptor according to claim 1, further comprising one or more dopants selected from the group consisting of graphene and rare earth composite oxides.

3. 3. The ceramic susceptor according to claim 2, wherein the dopant is contained in an amount of 0.05 to 2 parts by weight based on 100 parts by weight of the total weight of the alumina and aluminum nitride.

4. 3. The ceramic susceptor according to claim 2, wherein the dopant comprises magnesium oxide and graphene, and the magnesium oxide is contained in an amount of 0.05 parts by weight to 0.5 parts by weight and the graphene is contained in an amount of 0.05 parts by weight to 0.5 parts by weight, relative to 100 parts by weight of a total weight of the alumina and aluminum nitride.

5. the dopants include magnesium oxide, graphene, and yttria; 3. The ceramic susceptor according to claim 2, wherein the magnesium oxide is contained in an amount of 0.05 parts by weight to 0.5 parts by weight, the graphene is contained in an amount of 0.05 parts by weight to 0.5 parts by weight, and the yttria is contained in an amount of 0.05 parts by weight to 0.5 parts by weight, relative to 100 parts by weight of a total weight of the alumina and aluminum nitride.

6. The dopant includes magnesium oxide, graphene, yttria, and a rare earth composite oxide.

3. The ceramic susceptor according to claim 2, wherein the magnesium oxide is contained in an amount of 0.05 to 0.5 parts by weight, the graphene is contained in an amount of 0.05 to 0.5 parts by weight, the yttria is contained in an amount of 0.05 to 0.5 parts by weight, and the rare earth composite oxide is contained in an amount of 0.05 to 0.5 parts by weight, relative to 100 parts by weight of a total weight of the alumina and aluminum nitride.

7. 3. The ceramic susceptor according to claim 2, wherein the ceramic susceptor has a volume resistivity of 1.0E+10 Ω cm to 1.0E+13 Ω cm at 500°C and a thermal conductivity of 40 W / (m K) to 60 W / (m K) (K is Kelvin) at room temperature.

8. A method for producing the ceramic susceptor according to claim 1, comprising: a) mixing alumina, aluminum nitride, an alcohol compound, and a binder to prepare a mixture; b) drying the prepared mixture to prepare a powder from which alcohol compound components have been removed; c) compressing and molding the dried powder to produce a shaped preform; d) degreasing the prepared preform to remove the binder component; and e) sintering and polishing the degreased preform.

9. 9. The method of claim 8, wherein the sintering in step e) is performed at a temperature lower than 1,650°C.

10. 9. The method of claim 8, wherein in step a), one or more dopants selected from magnesium oxide, yttria, graphene, and rare earth composite oxides are further added and mixed.

Images