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 manufacturing method thereof, and more particularly to 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 manufacturing method thereof. [Background technology]

[0002] As semiconductor processes become more 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 field of processes for etching semiconductor devices or realizing other ultra-fine shapes. Such vacuum plasma equipment includes PECVD (plasma enhanced chemical vapour deposition) equipment that forms a deposition film on a substrate using a chemical vapor deposition method using plasma, sputtering equipment that forms a deposition film using a physical method, and dry etching equipment that etches a substrate or a material coated on a substrate into a specific pattern.

[0003] However, since high-temperature plasma is generated inside the vacuum plasma device, the chamber and the parts installed therein are likely to be damaged. In addition, certain elements and contaminant particles are likely to be generated from the surfaces of the chamber and the parts installed therein, contaminating the inside of the chamber. In particular, in the case of a plasma etching device, reactive gases such as F and Cl are injected under a plasma atmosphere, so the inner walls of the chamber and its internal parts are placed in a very severe corrosive environment. Generally, such corrosion primarily causes chemical and physical damage to the chamber and the parts installed therein, and secondarily causes contaminants and particles to be generated, resulting in an increase in the defect rate and a decrease in quality of products manufactured through processes inside the chamber.

[0004] If the chamber or the parts installed inside it are damaged in this way, the damaged parts of the equipment must be replaced, cleaned, or repaired, which incurs additional costs, and the process line must be stopped in order to do so, which increases the process time required for manufacturing the product. For these reasons, the metal susceptors that were previously installed inside the chamber are being replaced with ceramic susceptors, and these ceramic susceptors are made of sintered aluminum nitride (AlN) or alumina (AlN), which have excellent thermal conductivity. 2 O 3 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. In addition, it has a thermal expansion coefficient similar to that of silicon, so it is mainly used in semiconductor manufacturing equipment that requires high electrical resistance at high temperatures. Alumina is also a material that is stable at high temperatures, and has better electrical insulation and higher hardness than aluminum nitride.

[0006] Meanwhile, in recent semiconductor processes, the process is becoming finer and the equipment is becoming larger in diameter to improve yield, but such finer process and larger diameter equipment cause various problems in the semiconductor manufacturing process. Therefore, next-generation semiconductor process technology that can overcome these problems is required. In response to this, the process is carried out in a harsher environment of 600°C to 700°C, and in order to withstand this environment, the ceramic susceptor must satisfy the ceramic characteristics of a volume resistivity of 1.0E+10Ω·cm to 1.0E+13Ω·cm at 500°C and a thermal conductivity of 30W / mk or more, preferably 40W / mk or more, at room temperature.

[0007] However, in the case of aluminum nitride, the volume resistivity drops sharply at 500°C, which tends to cause leakage current, and in the case of alumina, the thermal conductivity at room temperature is very low at 20W / mk to 30W / mk. If the thermal conductivity at room temperature is only 20W / mk to 30W / mk, the temperature uniformity deviation becomes large, which causes problems such as a decrease in yield. Furthermore, if the temperature uniformity deviation of the thermal conductivity is large, it may result in a shortened product life due to thermal stress and thermal shock. Therefore, in order to prevent leakage current even at temperatures above 500°C, a ceramic susceptor is required that has 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 PRESENT EMBODIMENTS 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] In order to achieve the above object, the present invention provides alumina (Al 2 O 3 and aluminum nitride (AlN); and is free of secondary phases including an aluminum oxynitride phase (AlON phase).

[0010] The present invention also provides alumina (Al 2 O 3 and a dopant; wherein the dopant is magnesium oxide (MgO), yttria (Y 2 O 3 The present invention provides a ceramic susceptor comprising at least one of a rare earth composite oxide, graphene, and a rare earth composite oxide.

[0011] The present invention also provides a) alumina (Al 2 O 3a) mixing aluminum nitride (AlN), an alcohol compound, and a binder; b) drying the mixture to produce a powder from which the alcohol compound component has been removed; c) compressing and molding the dried powder to produce a preform processed into a certain shape; d) degreasing the preform to remove the binder component; and e) sintering and polishing the degreased preform.

[0012] The present invention also provides a) alumina (Al 2 O 3 a) mixing the mixture with magnesium oxide (MgO), a dopant, an alcohol compound, and a binder; b) drying the mixture to produce a powder from which the alcohol compound component has been removed; c) compressing and molding the dried powder to produce a preform processed into a certain shape; d) degreasing the preform to remove the binder component; and e) sintering and polishing the degreasing preform. 2 O 3 The present invention provides a method for producing a ceramic susceptor comprising at least one of a rare earth composite oxide, graphene, and a rare earth composite oxide. Effect of the Invention

[0013] The ceramic susceptor and the manufacturing method thereof according to the present invention have the advantage that they are superior in volume resistance at high temperatures and thermal conductivity at room temperature compared to conventional ceramic susceptors. [Brief description of the drawings]

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

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

[0016] The ceramic susceptor according to one embodiment of the present invention (first embodiment) is made of alumina (Al 2 O 3 ) and aluminum nitride (AlN), and is free of secondary phases including aluminum oxynitride phase (AlON phase).

[0017] As semiconductor processes become more and more miniaturized and highly integrated, the use of high-power plasma is inevitable. Accordingly, vacuum plasma devices using high-temperature plasma are widely used to etch semiconductor devices or realize other ultra-fine shapes. For this reason, in this industry, aluminum nitride (AlN) sintered bodies and alumina (AlN), which have excellent plasma corrosion resistance, have been used instead of conventional metal susceptors. 2 O 3 In particular, in recent years, semiconductor manufacturing processes have been carried out in harsher environments of 600°C to 700°C due to the miniaturization of processes and the use of larger diameter equipment to improve yields in semiconductor processes, and in order to withstand this environment, ceramic susceptors must satisfy 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 more, preferably 40 W / mk or more, at room temperature.

[0018] However, in the case of aluminum nitride, the volume resistivity drops sharply at 500°C, which tends to cause leakage current, and in the case of alumina, the thermal conductivity at room temperature is very low at 20W / mk to 30W / mk. If the thermal conductivity at room temperature is only 20W / mk to 30W / mk, the temperature uniformity deviation increases, which causes problems such as a decrease in yield. In addition, if the temperature uniformity deviation of the thermal conductivity is large, it may result in a shortened product life due to thermal stress and thermal shock. Therefore, the applicant has conducted extensive research and has invented a ceramic susceptor that can be used at high temperatures of 500°C or higher, has high volume resistivity at temperatures of 500°C or higher, can prevent leakage current, and has higher thermal conductivity at room temperature than normal, thereby solving the above problems.

[0019] The ceramic susceptor according to the first embodiment of the present invention is made of alumina (Al 2 O 3 ) and aluminum nitride (AlN) as the main phase, 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 in that 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 by mixing the alumina and aluminum nitride in the optimal ratio. Specifically, when alumina and aluminum nitride are mixed in the optimal ratio as in the present invention, as shown in Table 5 below, secondary phases such as AlON phase are not generated (i.e., secondary phases including AlON phase are not included), and the alumina phase and aluminum nitride phase are uniformly mixed and distributed without changing the crystal phase, thereby maximizing the physical properties of the ceramic susceptor. In addition, the sintering process in the process of manufacturing the ceramic susceptor is performed at an optimal temperature (less than 1,650°C, preferably 1,300°C to less than 1,650°C) to more thoroughly prevent the generation of secondary phases. 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% by weight and less than 99.8% by weight, preferably 70% to 95% by weight, more preferably 70% to 80% by weight, and most preferably 73% to 77% by weight of alumina. The ceramic susceptor according to the first embodiment of the present invention contains more than 0.2% by weight and less than 32% by weight, preferably 5% to 30% by weight, more preferably 20% to 30% by weight, and most preferably 23% to 27% by weight of aluminum nitride. If the alumina and aluminum nitride do not satisfy the above content ranges, the volume resistivity at 500°C and the thermal conductivity at room temperature do not satisfy the required conditions, and the ceramic susceptor does not satisfy the ceramic characteristics that the volume resistivity at 500°C is 1.0E+10 Ω·cm to 1.0E+13 Ω·cm and the thermal conductivity at room temperature is 30 W / mk or more.

[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 particles 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, and then pulverizing the mixture through a ball mill process. However, the particle size and mixing ratio are very diverse, and the ball mill process may be omitted, and the above example is not intended to limit the scope of the invention.

[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 is low, which may cause a problem of reacting with alumina at a low temperature to generate 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 is not formed, which may cause a problem of density reduction during final sintering. Furthermore, in the present invention, it is preferable to exclude aluminum nitride particles having a nanometer size 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 normal sintered body is applied to a substrate and a ceramic heater for semiconductors or an electrostatic chuck is used at high temperatures of 500°C or more, the substrate may break due to thermal shock because it cannot keep up with the sudden temperature change of the heating element. However, if a dopant is mixed in to improve the thermal shock resistance of the substrate and used in a heater or electrostatic chuck, the heat from the heating element can be efficiently transferred and the substrate can be prevented from breaking due to thermal shock.

[0027] The dopants of the present invention include magnesium oxide (MgO), yttria (Y 2 O 3 ), graphene, and rare earth composite oxides.

[0028] When the ceramic susceptor includes a dopant, the dopant may be included in an amount of 0.05 to 2 parts by weight, preferably 0.1 to 1 part by weight, 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 included in an amount of less than 0.05 parts by weight, or is not included at all, based on 100 parts by weight of the total weight of the alumina and aluminum nitride, the problems that have arisen in the past may occur similarly, or the effect obtained by using the dopant may be significantly reduced, the improvement in thermal conductivity may be insignificant, and the problem of non-sintering may occur. In addition, if the content of the dopant 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 decrease, and the thermal conductivity may decrease, and the sintering density may tend to decrease. In addition, the color of the product may become dark due to the influence of the dopant, or the color of the dopant may be expressed as it is. In addition, it is preferable that the dopant used in the present invention has a purity of 99% or more. The dopants are preferably contained in an amount of 0.05% by weight to 0.5% by weight.

[0029] Magnesium oxide, which is one of the dopants, may be included to improve the thermal conductivity and volume resistivity of the ceramic susceptor. The magnesium oxide is sintered with the alumina and / or aluminum nitride to form MgAl 2 O 4 phase and MgAlON phase formation, but MgAl 2 O 4 If the MgAlON phase or the MgAlON phase is excessively generated, the density will be low and the thermal conductivity may decrease, so even if the same components are used, it is necessary to adjust the content of the components. For example, in the present invention, the MgAl 2 O 4 Any one or more of the MgO phase and the MgAlON phase may be present in an amount of less than 1 wt %, preferably less than 0.8 wt %, 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 it is preferable to exclude nanometer-sized particles that may exhibit a relatively weak effect.

[0030] The yttria (Y 2 O 3) may be included to improve the thermal conductivity of the ceramic susceptor. The purity of the yttria is preferably 99% or more, and from the viewpoint of improving the physical properties by densification, the yttria particles are preferably nano-sized, 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 if it is contained in a small amount, problems such as the sintered body having the color of the yttria particles (yellow, etc.) may occur due to the characteristics of the nano-level yttria powder. In addition, if the average particle size (D50) of the yttria particles exceeds 150 nm, an incomplete sintered body is formed during sintering, and a problem of a decrease in thermal conductivity due to a decrease in density may occur. In particular, if the average particle size (D50) of the yttria particles is at the micrometer level, such problems may be more prominent.

[0031] The graphene may also be included to improve the thermal conductivity of the ceramic susceptor. The purity of the graphene is preferably 99% or more, and the graphene particles have a nano size, and 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 have a sufficient size to act as a bridge between the graphene particles, and the effect of improving the thermal conductivity may be negligible or nonexistent. In addition, if the average particle size (D50) of the graphene particles is more than 1.5 nm, the graphene particles may be entangled with each other and may not be dispersed well, which may cause a problem of reduced thermal conductivity due to a decrease in density.

[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 more. The rare earth composite oxide is preferably in the form of a powder, and there is no particular restriction on the size of the powder particles.

[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, and preferably may contain two to five different rare earth metals.

[0034] The rare earth composite oxide containing two to five different rare earth metals is preferably europium-gadolinium composite oxide (EuGdO X ), samarium-gadolinium oxide (SmGdO X ), cerium-europium oxide (CeEuO X ), samarium-cerium oxide (SmCeO X ), gadolinium-samarium oxide (GdSmO X ), lanthanum-cerium oxide (LaCeO X ) and other composite oxides containing two different rare earth metals; samarium-cerium-europium composite oxide (SmCeEuO X ), gadolinium-cerium-lanthanum composite oxide (GdCeLaO X ), europium-gadolinium-samarium oxide (EuGdSmO X) and other composite oxides containing three different rare earth metals; samarium-cerium-gadolinium-europium composite oxide (SmCeGdEuO X ) and gadolinium-samarium-europium-lanthanum composite oxide (GdSmEuLaO X ), 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 limitations 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 a variety of rare earth metals in various mixing 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 mixed so as to maximize the effect of the target rare earth composite oxide. For example, SmCeEuO X The ratio of rare earth metals (oxides) is 2:1:1:1, GdCeLaO X 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, any one of the rare earth metals may be dissolved in the remaining one (or any one) of the rare earth metal oxides. This changes the crystal structure of the rare earth metal oxide, and therefore the rare earth composite oxide may have an increased number of oxygen lattice defects compared to a single rare earth metal oxide. In this way, the rare earth composite oxide with an increased number of oxygen lattice defects has improved interface reactivity, and may effectively react with the interface or lattice oxygen of the components in the ceramic susceptor.

[0037] Furthermore, scandium oxide (Sc) is a rare earth metal oxide containing one rare earth metal. 2 O 3 ), lanthanum oxide (La 2 O 3 ), cerium oxide (CeO 2 ), praseodymium oxide (Pr 6 O 11 ), neodymium oxide (Nd 2 O 3 ), promethium oxide (Pm 2 O 3 ), samarium oxide (Sm 2 O 3 ), europium oxide (Eu 2 O 3 ), gadolinium oxide (Gd 2 O 3 ), terbium oxide (Tb 4 O 7 ), dysprosium oxide (Dy 2 O 3 ), Holmium oxide (Ho 2 O 3 ), erbium oxide (Er 2 O 3 ), thulium oxide (Tm 2 O 3 ), ytterbium oxide (YB 2 O 3 ) and lutetium oxide (Lu 2 O 3 ) are examples, 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 at least one of magnesium oxide, yttria, graphene, and rare earth metal oxides other than yttria. However, in the present invention, it is preferable that the dopant basically includes magnesium oxide. It is preferable to use magnesium oxide and graphene in combination as the dopant. It is 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.

[0039] When magnesium oxide and graphene are used in combination as dopants, the magnesium oxide may be included in an amount of 0.05 parts by weight to 0.5 parts by weight, and the graphene may be included 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] In addition, when magnesium oxide, graphene, and yttria are used in combination as dopants, the magnesium oxide may be contained in an amount of 0.05 parts by weight to 0.5 parts by weight, the graphene may be contained in an amount of 0.05 parts by weight to 0.5 parts by weight, and the yttria 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.

[0041] In addition, 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 parts by weight to 0.5 parts by weight, the graphene may be contained in an amount of 0.05 parts by weight to 0.5 parts by weight, the yttria may be contained in an amount of 0.05 parts by weight to 0.5 parts by weight, and the rare earth composite oxide 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.

[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 is made of alumina (Al2 O 3 ) and a dopant, the dopant being magnesium oxide (MgO), yttria (Y 2 O 3 ), graphene, and rare earth composite oxide.

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

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

[0045] The dopants preferably have a purity of 99% or more. Each of the dopants is preferably contained in an amount of 0.05% to 0.5% by weight. On the other hand, when the ceramic susceptor according to the second embodiment contains magnesium oxide (MgO) as a dopant, MgAl 2 O 4 This can cause the formation of a spinel phase. If MgAl 2 O 4If the spinel phase is produced in excess, the thermal conductivity may decrease, so even if the same components are used, it is necessary to adjust the content of the components.

[0046] Meanwhile, in the above description, the dopant includes at least one 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 also preferably basically includes magnesium oxide as a dopant. And, it is preferable to use magnesium oxide and graphene in combination as a dopant. And, it is more preferable to use magnesium oxide, graphene, and yttria in combination as a dopant. And, it is most preferable to use magnesium oxide, graphene, yttria, and a rare earth composite oxide in combination as a dopant.

[0047] When magnesium oxide and graphene are used in combination as a dopant, the magnesium oxide may be included in an amount of 0.05 wt % to 0.5 wt %, and the graphene may be included in an amount of 0.05 wt % to 0.5 wt %.

[0048] In addition, when magnesium oxide, yttria, and graphene are used in combination as dopants, the magnesium oxide may be contained at 0.05% by weight to 0.5% by weight, the yttria may be contained at 0.05% by weight to 0.5% by weight, and the graphene may be contained at 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 at 0.05% by weight to 0.5% by weight, the yttria may be contained at 0.05% by weight to 0.5% by weight, the graphene may be contained at 0.05% by weight to 0.5% by weight, and the rare earth composite oxide may be contained at 0.05% by weight to 0.5% by weight.

[0050] The ceramic susceptor according to the present invention as described above is characterized in that it 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 / mk or more, preferably 40 W / mk to 60 W / mk at room temperature. 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 is difficult to apply the ceramic receptor to the next generation semiconductor manufacturing process, and even if it is applied, there may be a problem of a sudden increase in leakage current. Also, if the thermal conductivity is not satisfied, there may be a problem of a large deviation in temperature uniformity, a decrease in yield, and 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 producing a ceramic susceptor according to the first embodiment includes the steps of: a) forming a ceramic susceptor by using alumina (Al 2 O 3 a) mixing aluminum nitride (AlN), an alcohol compound, and a binder; b) drying the mixture to produce a powder from which the alcohol compound component has been removed; c) compressing and molding the dried powder to produce a preform processed into a certain shape; d) degreasing the 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). Examples of such dopants include magnesium oxide (MgO), yttria (Y 2 O 3 ), 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 for improving 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 a spray drying method or a vacuum drying method, and the drying time may vary depending on the properties of the intended ceramic susceptor.

[0057] The step c) is a step of compressing the dried powder to produce a preform processed into a certain shape. The compression molding is an initial molding (i.e., first molding) process for controlling the powder dried in the step b) into a desired size and shape, and may be exemplified by press molding. In this case, in order to produce a product with a more precise specification, cold isostatic pressing (CIP) may be additionally performed as necessary. The press molding is preferably performed at room temperature and under normal air, but is not limited thereto, and the atmosphere during molding may be such that it does not affect the molding of the mixture. In addition, after the molding process of the step c), a preform may be produced by processing using a green processing method (also called raw processing as it is performed before sintering) or the like.

[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°C to 600°C for 60 hours or less.

[0059] In step e), the degreased preform is sintered (second molding) and polished to manufacture a ceramic substrate. The sintering is preferably performed by hot press sintering as a second molding (i.e., second molding) process to further improve the volume resistivity of the ceramic susceptor. Furthermore, if the degreased preform is sintered at a temperature of 1,650°C or higher, alumina reacts with aluminum nitride to form an AlON phase, which causes a problem of reduced thermal conductivity. Therefore, the sintering in step e) must be performed at a temperature lower than 1,650°C, preferably at a temperature between 1,300°C and 1,650°C.

[0060] In addition, the method for producing a ceramic susceptor according to the second embodiment includes the steps of: a) forming a ceramic susceptor by using alumina (Al 2 O 3 b) mixing the mixture with magnesium oxide (MgO), a dopant, an alcohol compound, and a binder; c) drying the mixture to produce a powder from which the alcohol compound component has been removed; c) compressing and molding the dried powder to produce a preform processed into a certain shape; d) degreasing the preform to remove the binder component; and e) sintering and polishing the degreasing preform, in which the dopant is magnesium oxide (MgO), yttria (Y 2 O 3 ), 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, and are not intended to limit the present invention.

[0062] [Examples 1 to 8, Comparative Examples 1 to 8] Production of ceramic susceptor The raw materials were mixed according to the composition in Table 1 below, and then a small amount of ethanol and polyvinyl butyral (binder) were mixed 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, and the degreased preform was 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 (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 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 2 below.

[0065] In addition, test pieces were prepared from each of the ceramic susceptors prepared 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 thermal conductivity at room temperature. The results are also shown in Table 2 below.

[0066] In addition, the density of each of the ceramic susceptors manufactured in Examples 1 to 8 and Comparative Examples 1 to 8 was calculated using the 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 elements 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 elements in 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 vs. Comparative Examples 1 and 2, the comparison of Examples 3 and 4 vs. Comparative Examples 3 and 4, the comparison of Examples 5 and 6 vs. Comparative Examples 5 and 6, and the comparison of Examples 7 and 8 vs. 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 the case of Examples 7 and 8 in which all dopants were used in amounts of 0.05 wt % to 0.5 wt %, respectively, the thermal conductivity at room temperature exceeded 40 W / mk.

[0071] In addition, comparing Example 2 and Comparative Example 2, Example 2 used 0.5 wt% MgO, and 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 MgAl 2 O 4 This is due to the formation of excess amounts of MgAlON or MgAlON phases in the final product exceeding 0.6 wt % and their fraction increasing. 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 physical properties In order to derive the optimal 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] *Al 2 O 3 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 therefore the volume resistivity at high temperatures and the thermal conductivity at room temperature vary.

[0078] More specifically, the change in physical properties depending on the ratio of aluminum nitride added was 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 excellent in Production Examples 3 to 5, and Production Example 5, in which alumina and aluminum nitride were mixed in a weight ratio of 75:25, was generally the best.

[0079] This means that if the aluminum nitride content is too low, the Al phase will be the main phase. 2 O 3 If the aluminum nitride content is excessively high, the proportion of the AlN phase increases, and although there is an effect of improving thermal conductivity, there is a tendency for the volume resistivity and hardness to decrease.

[0080] [Manufacturing Examples 5-1 to 5-5] Evaluation of physical properties of ceramic susceptors depending on 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 changing 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] *Al 2 O 3 , AlN and AlON units: weight %

[0084] Alumina reacts with aluminum nitride at a certain temperature or higher 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 has a large effect on the physical properties. FIG. 1 is an XRD graph showing the physical properties of the ceramic susceptor depending on the sintering temperature, and FIG. 2 is a graph showing the correlation between the alumina content and the sintering temperature. Referring to FIGS. 1 and 2 and Table 1, at a sintering temperature of 1,500°C, the volume resistance was not measured due to non-sintering, and the thermal conductivity and density were measured very low. Analysis of the XRD graph showed that an AlON phase was generated at a sintering temperature of 1,650°C or higher, and the volume resistance increased as the AlON content increased, but the thermal conductivity decreased rapidly. Therefore, it can be seen that the sintering in the present invention is preferably performed at a temperature 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 a small amount of ethanol and polyvinyl butyral (binder) were further mixed 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, and the degreased preform was sintered in a high-temperature pressure sintering furnace (pressure of 250 bar, temperature of 1,630°C) and polished to produce 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 pieces were prepared from each of the ceramic susceptors prepared 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 measured at room temperature to calculate the thermal conductivity. The results are also shown in Table 9 below.

[0089] In addition, the density of each of the ceramic susceptors manufactured in Examples 9 to 20 and Comparative Examples 9 to 20 was calculated using the 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 elements 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 elements of 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 comparison of Examples 9 to 11 and Comparative Examples 9 to 11, the comparison of Examples 12 to 14 and Comparative Examples 12 to 14, the comparison of Examples 15 to 17 and Comparative Examples 15 to 17, and the comparison of Examples 18 to 20 and Comparative Examples 18 to 20, in which each dopant was used at a content of 0.05 wt% to 0.5 wt%, was superior to Comparative Examples 9 to 20 in which even one dopant was used at more than 0.05 wt% to 0.5 wt%.

[0093] On the other hand, when GNP (graphene nanopowder) was added as a dopant in addition to MgO, the effect was negligible when the GNP was used at less than 0.05 wt%, but the thermal conductivity improved when the GNP was used at 0.05 wt% to 0.5 wt%. And, when the GNP was used at a content exceeding 0.5 wt%, the volume resistivity, density, and hardness showed a tendency to rapidly decrease.

[0094] In addition to MgO and GNPs, nano-sized yttria (Y 2 O 3 Even when yttria was added up to 0.05wt%~0.5wt%, it showed the effect of increasing sinterability, volume resistivity and thermal conductivity. However, when yttria was used at a content exceeding 0.5wt%, it showed a tendency of decreasing thermal conductivity due to the reaction with alumina to form a large amount of secondary phases such as YAP, YAM and YAG.

[0095] In addition, MgO, GNP and NanoY were used as dopants. 2 O 3When rare earth composite oxide was added in an amount of 0.05% to 0.5% by weight, 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% by weight, both the volume resistivity and thermal conductivity tended to decrease rapidly.

[0096] Furthermore, comparing Example 11 and Comparative Example 10, Example 11 used 0.5 wt% MgO, and 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 MgAl 2 O 4 This is due to the formation of excess amounts of MgAlON or MgAlON phases in the final product exceeding 0.6 wt % and increasing their 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); A ceramic susceptor that does not contain secondary phases, including aluminum oxynitride phase (AlON phase).

2. 2. The ceramic susceptor of claim 1, wherein the alumina content is more than 68% by weight and less than 99.8% by weight, and the aluminum nitride content is more than 0.2% by weight and less than 32% by weight.

3. The ceramic susceptor is made of magnesium oxide (MgO), yttria (Y 2 O 3 2. The ceramic susceptor according to claim 1, further comprising at least one dopant selected from the group consisting of arsenic, graphene, and rare earth complex oxide.

4. 4. The ceramic susceptor according to claim 3, 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.

5. 4. The ceramic susceptor according to claim 3, 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.

6. the dopants include magnesium oxide, graphene, and yttria; 4. The ceramic susceptor according to claim 3, 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.

7. The dopant includes magnesium oxide, graphene, yttria, and a rare earth composite oxide; 4. The ceramic susceptor according to claim 3, 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, the yttria is contained in an amount of 0.05 parts by weight to 0.5 parts by weight, and the rare earth composite oxide 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.

8. The ceramic susceptor according to claim 1, 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 30 W / mk or more at room temperature.

9. The ceramic susceptor according to claim 3, 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 / mk to 60 W / mk at room temperature.

10. alumina; and a dopant, The ceramic susceptor, wherein the dopant includes at least one of magnesium oxide, yttria, graphene, and a rare earth composite oxide.

11. 11. The ceramic susceptor according to claim 10, wherein the content of the alumina is 98% to 99.95% by weight, and the content of the dopant is 0.05% to 2% by weight.

12. The dopant includes magnesium oxide, yttria, graphene, and a rare earth composite oxide; 11. The ceramic susceptor according to claim 10, wherein the magnesium oxide is contained in an amount of 0.05% to 0.5% by weight, the yttria is contained in an amount of 0.05% to 0.5% by weight, the graphene is contained in an amount of 0.05% to 0.5% by weight, and the rare earth composite oxide is contained in an amount of 0.05% to 0.5% by weight.

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

14. The method of claim 13, wherein the sintering in step e) is performed at a temperature lower than 1,650° C.

15. 14. The method of claim 13, wherein in step a), at least one dopant selected from magnesium oxide, yttria, graphene, and rare earth composite oxide is further added and mixed.

16. A method for producing the ceramic susceptor according to claim 10, comprising the steps of: a) mixing alumina, a dopant, an alcohol compound, and a binder; b) drying the mixture to produce a powder from which the alcohol compound components have been removed; c) compressing and molding the dried powder to produce a shaped preform; d) degreasing the preform to remove the binder component; and e) sintering and polishing the degreased preform, The method for producing a ceramic susceptor, wherein the dopant includes at least one of magnesium oxide, yttria, graphene, and a rare earth composite oxide.

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