JP2009235558A - Member coated with aluminum nitride by thermal splaying and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal-spraying deposit having a low porosity and a high aluminum nitride content since thermal-spraying deposit of aluminum nitride excellent in thermal conductivity and insulating properties is desired to be formed on members for electrostatic chucks, heaters, and plasma-processing chambers for use in the production of semiconductors, etc. or on members for use in radiating insulating substrates for power devices. <P>SOLUTION: In the member coated with aluminum nitride by thermal spraying, a thermal-spraying deposit is formed on at least part of a base, and particles of a thermal-spraying deposit is constituted of fine aluminum nitride particles which are nearly spherical and have a diameter of ≥1 to ≤10 μm on the average, and the member is characterized in that interstices among the aluminum nitride particles are filled with a Group IIIA and/or Group IIA element compound, and that the deposit has a porosity of ≤15%. This member can be produced by conducting thermal spraying with an aluminum nitride powder having an average particle diameter of 1 to 10 μm or with a powder mixture obtained by incorporating a Group IIIA and/or Group IIA element compound into the same aluminum nitride powder. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a member such as an electrostatic chuck, a heater or a plasma processing chamber in the manufacture of a semiconductor or the like and a heat-radiating insulating substrate of a power device, and particularly to impart the characteristics of aluminum nitride to the surface of the member as a sprayed film. Furthermore, it relates to a material having a high nitride content and providing a strong and dense sprayed film.

  Aluminum nitride is an insulating material with high thermal conductivity and has excellent resistance to fluorine plasma. For this reason, in a film forming apparatus such as CVD (Chemical Vapor Deposition) or a plasma etching apparatus in a manufacturing process of a semiconductor element or the like, an electrostatic chuck for holding a component that requires such characteristics, for example, a wafer substrate In the wafer substrate, in order to keep the wafer substrate uniformly at a predetermined temperature in the plane, in the wafer substrate heater, in the insulating part integrally formed with the metal electrode, in the plasma etching or CVD It is used for a chamber protection member in plasma cleaning of a process.

  Examples of the method of forming the aluminum nitride portion include a spraying method and a sintering method. However, the forming method is not necessary, and the spraying method is used from the viewpoint that the aluminum nitride portion can be formed even for complex parts. It is preferable to form.

  However, if an aluminum nitride portion is simply formed by a thermal spraying method, depending on the thermal spraying conditions, it is oxidized and decomposed before melting, and it is not easy to form an aluminum nitride film. For this reason, various methods have been studied for the thermal spraying method of aluminum nitride.

  For example, a method of mixing and spraying alumina and carbon and heat-treating the obtained sprayed film in nitrogen has been reported (for example, see Patent Document 1), but a high temperature of about 1800 ° C. is required, Cannot be applied to metal substrates.

  Next, a method of thermal spraying using a powder obtained by mixing and granulating aluminum nitride and alumina has been reported (for example, see Non-Patent Document 1). However, in this report, the amount of AlN present in the sprayed film is about 47%, and there are many pores in the sprayed film. The reported thermal conductivity is lower than that of the sintered body of alumina ceramic, and further improvement in thermal conductivity is achieved. Is desired.

  Further, a cermet powder in which a metal, a nitride of the metal and an oxide thereof are mixed, specifically, a mixed powder of metal silicon, silicon nitride, and silicon oxide is thermally sprayed to form an undercoat of a silicon-based cermet. A technique for forming a ceramic sprayed film containing zirconia is reported (for example, see Patent Document 2). However, there is a possibility that the insulating properties may be lowered by mixing the nitride with the metal.

  Furthermore, it is also proposed to deposit aluminum nitride by performing reactive spraying of metal aluminum powder or metal aluminum powder and aluminum nitride by plasma spraying containing nitrogen gas in a vacuum (for example, Patent Documents 3 and 4). However, since it is a vacuum process, thermal spraying on a large member is not easy, and there is a concern that the insulating property may be lowered due to the remaining metal aluminum.

Japanese Patent Laid-Open No. 5-051285 JP 2003-313077 A JP 2004-083929 A JP 2006-307298 A JP 2001-332668 A H. Yang, W .; Luan, ST. Tu “AlN / Al 2 O 3 Composite Coating Deposited by Plasma Spray” Proceedings of the 1st Asian Thermal Spray Conference, 41 (2005)

  As explained above, by spraying aluminum nitride on members such as electrostatic chucks, heaters, and chambers of CVD and other film forming apparatuses and plasma etching apparatuses in the manufacturing process of semiconductor elements and the like, it is essential in the sintering method. Although it is expected that the high-temperature treatment process is omitted and the plasma resistance is directly imparted to the metal substrate, it is difficult to form a dense sprayed aluminum nitride sprayed film with high productivity.

  An object of the present invention is to provide a thermal spray member formed with an aluminum nitride thermal spray film which is suitable for the above-mentioned applications and has good adhesion to a substrate, and a method for producing the thermal spray member.

  As a result of intensive studies in view of the above situation, the present inventors have performed atmospheric pressure plasma spraying using a powder of aluminum nitride having a specific size as a spraying raw material, It is possible to provide a member formed with a sprayed aluminum nitride film having a high nitride ratio and good adhesion to the base material by causing the powder to collide with the base material at a high temperature at a temperature at which the surface layer is oxidized. It has been found that by using a mixed powder in which an aluminum nitride powder and a group IIIA and / or group IIA compound powder are mixed and dispersed in place of the aluminum powder, a member formed with a denser aluminum nitride sprayed film can be provided. The present invention has been completed.

  That is, the present invention relates to an aluminum nitride sprayed member in which a sprayed film made of substantially spherical aluminum nitride particles having an average diameter of 1 μm to 10 μm is formed on a substrate.

  Hereinafter, the member of this invention is demonstrated in detail.

  When schematically representing the aluminum nitride sprayed member of the present invention, as shown in FIG. 1, a substantially spherical aluminum nitride particle 13 having an average diameter of 1 μm or more and 10 μm or less is deposited on the substrate 11. It consists of a sprayed film 12. As a mechanism for depositing the aluminum nitride particles, it is considered that a part of the surface of the aluminum nitride particles is oxidized by the thermal spraying to cause adhesion between the particles, and a sprayed film is deposited.

  The average diameter of the aluminum nitride particles on the substrate is 1 μm or more and 10 μm or less, preferably 2 μm or more and 8 μm or less. The larger the average diameter of the aluminum nitride particles, the less the thermal conductivity is reduced by the oxide layer on the surface of the particles generated during the thermal spraying process. By increasing the amount of aluminum, the sprayed film is rebounded without adhering to the base material during spraying, so that it becomes difficult to form a sprayed film.

  In the present invention, the average diameter means an average value of the diameters of the individual particles constituting the sprayed film, and the diameter of each particle by SEM (scanning electron microscope) observation of the sprayed film cross section. Measured or measured by methods such as observing composition images of nitrogen, oxygen, and aluminum with an EPMA (electron probe microanalyzer), EDS (energy dispersive spectrometer), and measuring the diameter of each particle. Value.

  In addition, the aluminum nitride particles are rounded because the surface is slightly oxidized and melted during the thermal spraying process. Therefore, the substantially spherical shape in the present invention specifically means a spherical or elliptical round shape. The shape of the aluminum nitride particles can be determined by polishing the cross section of the sprayed film and observing the composition image of nitrogen, oxygen, and aluminum with SEM observation or EPMA or EDS.

  The thickness of the aluminum nitride sprayed film is preferably 5 μm or more and 500 μm or less. If the thickness is less than 5 μm, the insulating property may be poor. If the thickness is greater than 500 μm, the sprayed film may be easily peeled off from the substrate.

  Since the aluminum nitride particles constituting the aluminum nitride sprayed film are crushed only on the surface during thermal spraying, gaps are formed between the particles. If a gap is generated in the sprayed film, the porosity of the sprayed film increases, which may cause a decrease in thermal conductivity, a decrease in insulation, and the like. Therefore, as shown in FIG. 2, pores are reduced by filling the gaps between the aluminum nitride particles 23 with a group IIIA and / or group IIA compound 24. The present inventors consider that the group IIIA and / or IIA compound melts by thermal spraying and therefore accumulates in the gap formed by the aluminum nitride particles as splats. In order to obtain good physical properties (thermal conductivity, withstand voltage, etc.) of aluminum nitride, the porosity is preferably 15% or less.

  As a method for measuring the porosity in the present invention, the sprayed film is peeled off from the base material, the bulk density is measured by the Archimedes method, and the ratio is calculated from the ratio with the true density, or the cross section of the sprayed film is observed by SEM or the like. Then, the pore portion is traced, the area of the pore portion is measured using image processing software, and the area is divided by the area of the pore portion and the sprayed film.

  Group IIIA compounds mean rare earth metal oxides such as Sc, Y, La, and Ce, fluorides, phosphates, etc., and Group IIA compounds mean alkaline earth metals such as Mg, Ca, Sr, and Ba. Means an oxide, fluoride, phosphate and the like, and is preferably an insulating compound. The content of the group IIIA and / or group IIA compound in the sprayed film is preferably 1 wt% or more and 30 wt% or less. If it is less than 1 wt%, the pore reduction effect may be small, and if it exceeds 30 wt%, the thermal conductivity may be lowered. The content of the group IIIA and / or group IIA compound in the sprayed film is more preferably 1 wt% or more and 25 wt% or less.

  Further, as the base material of the thermal spray member of the present invention, a metal such as aluminum, molybdenum or copper having a thermal conductivity of 100 W / mK or more, a composite metal or alloy such as copper-molybdenum or aluminum-silicon, or aluminum-silicon carbide. Examples thereof include metal ceramic composite materials such as silicon-silicon carbide. The surface of these base materials may be roughened by sandblasting or hydrofluoric acid to make it easier to adhere the sprayed film. The surface roughness Ra of the substrate surface is preferably 0.1 to 15 μm. Here, the surface roughness Ra refers to the arithmetic average roughness Ra described in JIS B0601: 2001. On the other hand, the thermal conductivity of the aluminum nitride sprayed film is preferably 10 W / mK or more.

  As described above, the surface of each aluminum nitride particle is melted by being slightly oxidized during the thermal spraying process and bonded to adjacent particles. FIG. 3 shows an example of an X-ray diffraction chart of the aluminum nitride sprayed film used in the present invention. The (100) plane (2θ: 33.256 °) of hexagonal aluminum nitride is the main peak 31, and the peak 32 of the (400) plane (2θ: 45.789 °) of γ aluminum oxide is seen as the other phase. . In addition, when the plasma output is high, a peak of the α aluminum oxide (104) plane (2θ: 35.103 °) may occur. In order to firmly bond the particles and ensure a certain degree of thermal conductivity, in the X-ray diffraction peak intensity of the sprayed film, the γ aluminum oxide (400) plane and the α aluminum oxide (with respect to the peak intensity of the aluminum nitride (100) plane) It is preferable that the ratio with the sum of the peak intensity of the 104) plane is 0.05 or more and 0.2 or less. Here, when this ratio is less than 0.05, the bonding between the aluminum nitride particles is weak, and it may be better to add the IIIA group and / or IIA group compound to strengthen the bonding between the particles, and this ratio is If it exceeds 0.2, thermal conductivity may be sacrificed.

  The aluminum nitride sprayed member of the present invention is an electrostatic chuck for holding a wafer substrate or a heater for heating the wafer substrate in a film forming apparatus such as CVD or a plasma etching apparatus in a manufacturing process of a semiconductor element or the like. Can be used. Specifically, as shown in FIG. 4, at least a first sprayed film 42 is formed on a base material 41 made of a metal ceramic composite material such as an aluminum alloy, a metal such as stainless steel, or aluminum-silicon carbide or silicon-silicon carbide. The metal electrode layer or heater layer 43 and the second sprayed film 44 are formed, and the first sprayed film and / or the second sprayed film is the above-described aluminum nitride sprayed film, or the aluminum nitride particles and the group IIIA and / or IIA. It is a sprayed film made of a group compound.

  The aluminum nitride sprayed member of the present invention is also formed by nitriding a portion exposed to plasma as a member inside a film forming apparatus such as CVD, a plasma etching apparatus, a plasma cleaning apparatus, an ashing apparatus or the like in a manufacturing process of a semiconductor element or the like. An aluminum sprayed film can be formed and used.

  As a suitable example of the member on which the aluminum nitride sprayed film used for the portion exposed to the plasma is formed, a dome (bell jar), a cylinder, or a ring can be cited, and the surface roughness Ra of the aluminum nitride sprayed film is 1 μm or more. It is preferably 15 μm or less. In these parts, not only the surface of the member is corroded by plasma, but also the wafer is etched, cleaned, or ashed, so that a deposited film adheres to the surface of the member, and dust is generated when it hits the plasma. Adhesiveness of the deposited film is increased by setting the arithmetic average roughness Ra of the aluminum nitride sprayed film to 1 μm or more. In addition, although a thermal load is applied to the deposited film by being exposed to plasma, the temperature change is mitigated by releasing the deposited film on a high thermal conductivity aluminum nitride sprayed film. By these, dust generation can be reduced. Here, when the arithmetic average roughness Ra exceeds 15 μm, the sprayed film thickness necessary for coating the arithmetic average roughness of the substrate with the aluminum nitride sprayed film becomes thick, and the productivity may be lowered. As the base material of these components, titanium, quartz glass having high insulating properties, ceramics, or the like can be used in addition to the above-described material having high heat conduction. In order to introduce high frequency by inductive coupling from the outside to the inside of the member, a highly insulating base material is used.

  The aluminum nitride sprayed member of the present invention can be further used as a heat dissipation insulating substrate for power devices. In that case, as shown in FIG. 5, the base material is a metal heat dissipation substrate 51, and an aluminum nitride sprayed film 52 is formed thereon. Base materials include metals such as aluminum, molybdenum, and copper with thermal conductivity of 100 W / mK or more, composite metals and alloys such as copper-molybdenum and aluminum-silicon, and metals such as aluminum-silicon carbide and silicon-silicon carbide. Ceramic composite materials can be used. The aluminum nitride sprayed film 52 preferably has a thermal conductivity of 10 W / mK or more. The surface of the aluminum nitride sprayed film 52 is polished to place the power device 55 thereon, and the solder 54 is placed on the aluminum nitride sprayed film 52 to join the power device 55, so that a metal 53 such as copper or nickel is plated or sprayed. ing.

  Furthermore, in the aluminum nitride sprayed member of the present invention, it is possible to use a member sealing pores present in the aluminum nitride sprayed film. The sealing referred to in the present invention refers to a state in which pores in the sprayed film are filled with some sealing agent, and examples of the sealing agent include thermosetting such as epoxy, acrylic, silicon, and fluorine. An inorganic oxide coating agent composed of a mold, a room temperature curable resin, polysilazane, aluminum, an organic metal of yttrium, or the like can be used.

  Examples of the sealing method include a method of curing after applying a sealing agent to the surface of the sprayed film, and a method of curing after spraying the sprayed film in a liquid sealing agent in a vacuum. . By sealing, the properties of the sprayed film such as the strength, thermal conductivity, and dielectric strength voltage described later are improved.

  In the aluminum nitride sprayed member of the present invention, the withstand voltage of the aluminum nitride sprayed film is preferably 0.15 MV / cm or more, and more preferably 0.2 MV / cm or more. When the withstand voltage is lower than 0.15 MV / cm, it is necessary to thicken the aluminum nitride sprayed film when used as a heat dissipation insulating substrate of a power device or a member of a plasma processing apparatus, and heat dissipation to the substrate may be reduced. . Examples of a method for improving the withstand voltage of the aluminum nitride sprayed film include improving the density of the sprayed film and sealing.

  In the method for producing an aluminum nitride sprayed member of the present invention, for example, an aluminum nitride powder having an average particle diameter of 1 μm or more and 10 μm or less is supplied to a thermal spraying apparatus, and the average temperature of the aluminum nitride particles immediately before the substrate is 2200 ° C. or more and 2280 ° C. Hereinafter, it can be manufactured by forming an aluminum nitride sprayed film on a base material by atmospheric pressure plasma spraying under conditions where the average flight speed is 400 m / s or more and 600 m / s or less. The temperature and speed at the time of thermal spraying of the aluminum nitride powder can be measured using, for example, a product name “DPV-2000” manufactured by TECNAR of Canada. In DPV-2000, the sprayed particle temperature is measured by measuring the emission of the particles with a two-color thermometer, and the flight speed of the particles is measured from the time when the emitted particles pass through the sensor. When the temperature of the particles is less than 2200 ° C., the deposition efficiency of the sprayed film is low, and adhesion of the film to the substrate may be weakened. When the temperature exceeds 2280 ° C., oxidation and decomposition of aluminum nitride are promoted.

  In the aluminum nitride sprayed member of the present invention, in order to fill the gap between aluminum nitride particles with group IIIA and / or group IIA compound particles, for example, an aluminum nitride powder having an average particle size of 1 μm to 10 μm, and an average particle size Is supplied together with a Group IIIA and / or Group IIA compound of 1 μm or more and 10 μm or less to the thermal spraying apparatus, the average temperature of the molten particles immediately before the substrate is 2200 ° C. or more and 2280 ° C. or less, and the average line speed is 400 m / s or more It can be obtained by atmospheric pressure plasma spraying under conditions of 600 m / s or less.

  The average particle diameter of the thermal spray raw material powder used in the present invention is preferably 1 to 10 μm, more preferably 2 to 2 as an average particle diameter measured by a laser diffraction method or an average diameter of a powder obtained by SEM observation of the powder. 8 μm. When a powder having an average particle size larger than 10 μm is used, as described above, the nitride powder having a high melting point may not melt and the sprayed film may not be deposited. On the other hand, when the average particle size is smaller than 1 μm, the rate of collision with the substrate is decreased, the adhesion is deteriorated, and the oxidation is promoted, so that the ratio of aluminum nitride may be decreased. In general, ceramics have a high melting point and low thermal conductivity, so it is difficult to obtain a uniform molten state, so finer-grained powder is used compared to metal powder. It is difficult to throw into the position, and problems such as troubles are likely to occur during feeding. Therefore, with normal plasma, powder with an average particle size of 30-50 μm and high-power high-efficiency water-stabilized plasma of about 100 μm (For example, see Yukio Oki et al., Japan Thermal Spray Association, “Introduction to Thermal Spray Technology” (2006), pages 191 to 192). On the other hand, the average particle diameter of the raw material powder used in the present invention is considerably finer than before. The supply of such fine powder is achieved by using, for example, a product of “TechnoServ” using a surface scanning method, a product name “AM-30”, a product of German Thermico using a capacitance method, and a product name “CPF-2HP”. it can.

  The thermal spray film forming method used in the present invention is preferably plasma spraying. In particular, it is preferable to perform thermal spraying with plasma having a high output and a high gas flow rate. Examples of the high output include plasma of 50 kW or more, and the high gas flow rate of 120 SLM (Standard Litter Per Minute) or more. Although the effect of increasing the output and gas flow rate is not clear, it is considered that increasing the gas flow rate shortens the time that the nitride powder stays in the plasma and suppresses oxidation and decomposition. Usually, when the gas flow rate is increased, the powder is not melted, so that the sprayed film is hard to be deposited. However, it is considered that the molten layer is formed on the powder surface by increasing the plasma output.

In the production method of the present invention, the supply of the raw material powder to the spray gun is preferably a method of supplying the inside of the plasma. As a spray gun of a system for supplying powder into the plasma, for example, trade name “Axial III” manufactured by Northwest Mettech, Canada can be mentioned. In this spray gun, since the three plasma electrodes are arranged at intervals of 120 degrees around the spray powder supply nozzle, since the spray powder is introduced into the plasma center, the plasma is N ₂ or H _2, etc. In the case of a reducing atmosphere, the thermal spraying powder can also prevent oxidation due to contact with oxygen.

  FIG. 6 shows a conceptual diagram of an example of a plasma spraying apparatus of a powder supply system into the plasma. In the plasma spraying apparatus, a plasma jet 62 formed between the three anodes 61 and the cathode 60 by arc discharge is collected by a convergence 64. Using the assembled plasma jet as a heat source, the sprayed powder 63 is introduced into the center and melted, and the melted sprayed powder collides with the base material 66 at the flow rate of the plasma gas.

In the production method of the present invention, an inert gas such as N ₂ or Ar or a reducing gas such as H ₂ can be used as the spray gas in forming the sprayed film. If oxygen is present in the thermal spray gas, the nitrogen in the thermal spray raw material powder is oxidized during thermal spraying, and the nitrogen content of the thermal spray film is greatly reduced. Therefore, the oxygen concentration in the thermal spray gas is preferably as low as possible. When spraying nitride powder in it, by increasing the power of spraying, a small amount of the surface of the sprayed powder that flies at high temperature and the sprayed powder after deposition changes to oxide, and this oxide is converted into nitride. It can also be a role to connect each other. The presence and amount of nitride in the sprayed film can be confirmed on the surface of the sprayed film by X-ray diffraction, and the amount of nitrogen in the sprayed film can be measured by EPMA. Further, the amount of group IIIA and / or group IIA in the sprayed film can be measured by performing fluorescent X-ray analysis or the like.

  In the production method of the present invention, the spray distance, which is the distance between the tip of the spray gun and the substrate under normal pressure, is preferably 40 to 150 mm. If the spraying distance exceeds 150 mm, the sprayed powder will be cooled until it adheres to the substrate, and the sprayed film may not be deposited on the substrate. If the spraying distance is shorter than 40 mm, the temperature of both the substrate and the sprayed film will rise. Therefore, the cause of cracking of the sprayed film and the base material and the nitrogen content in the sprayed film may be reduced.

  Furthermore, although the spraying power to be charged when spraying the spray frame on the base material varies depending on the apparatus to be used, for example, in the case of a plasma spraying apparatus as shown in FIG. 6, the spraying power may be 50 kW or more and 150 kW or less. it can.

  In the above description, it has been described that the aluminum nitride sprayed member of the present invention is obtained by a plasma spraying method with a high output and a high gas flow rate. A manufacturing method for obtaining the aluminum nitride sprayed member of the invention will be described below.

That is, (1) an aluminum nitride powder having an average particle diameter of 1 μm or more and 10 μm or less and a mixed powder in which a lubricant of 0.1 to 5 wt% is added to the weight of the aluminum nitride powder, or an average particle diameter of 1 μm or more Group IIIA and / or Group IIA compound powder of 10 μm or less, aluminum nitride powder having an average particle diameter of 1 μm or more and 10 μm or less, and mixing in which 0.1 to 5 wt% of lubricant is added to the total weight of these powders A method of supplying powder to a thermal spraying apparatus as a thermal spray powder and forming an aluminum nitride sprayed film on a substrate by atmospheric pressure plasma spraying, or
(2) An aluminum nitride powder having an average particle size of 1 μm to 10 μm, or a group IIIA and / or IIA compound powder having an average particle size of 1 μm to 10 μm and an aluminum nitride powder having an average particle size of 1 μm to 10 μm The mixed powder is supplied to the outside of the plasma outlet of the spray gun at two or more locations perpendicular to the plasma jet, and the base material is an aluminum nitride sprayed film by atmospheric pressure plasma spraying under the condition that the spraying distance is 40 mm or more and 70 mm or less. It relates to the method of forming above.

  First, in the production method (1), an average particle diameter of 1 μm or more and 10 μm or less of an aluminum nitride powder and a mixed powder in which a lubricant of 0.1 to 5 wt% is added to the weight of the aluminum nitride powder, or Group IIIA and / or Group IIA compound powder having an average particle size of 1 μm to 10 μm, aluminum nitride powder having an average particle size of 1 μm to 10 μm, and 0.1 to 5 wt% of the total weight of these powders It is characterized in that a mixed powder to which a lubricant is added is used as a thermal spray powder.

  Examples of the lubricant include saturated fatty acids such as stearic acid, behenic acid, and lignoceric acid, and paraffin. By adding these lubricants to the thermal spraying raw material powder, it becomes possible to spray the thermal spraying raw material powder at a high gas flow rate without feeding it to the thermal spraying device. The effect of reducing such troubles occurs. The principle of this effect is considered that the lubricant present on the powder surface reduces friction between the powders.

  As the amount of the lubricant, when the aluminum nitride powder is used alone as the spray powder, the amount of the aluminum nitride powder is 0.1 to 5 wt% of the weight of the aluminum nitride powder and the group IIIA and / or group IIA compound. When the mixed powder is used as the thermal spray powder, it is preferable to add an amount of 0.1 to 5 wt% of the mixed powder weight. If the addition amount of the lubricant is less than 0.1 wt%, the lubrication effect is reduced, so that a supply trouble is likely to occur, and if it is more than 5 wt%, the lubricant remains in the sprayed film, so that the film quality of the sprayed film is increased. May decrease.

  As a method of adding a lubricant to aluminum nitride powder and a method of adding a lubricant to a mixed powder of aluminum nitride powder and a group IIIA and / or group IIA compound, for example, a dry process is applied to each powder and lubricant mixture. Or wet ball milling.

  The thermal spray raw material powder thus prepared has improved fluidity, so that a normal disk type feeder (for example, trade name “Twin-120A” made by Sulzer Metco or trade name “1264 Powder Feeder” made by Praxair), vibration Using a type feeder (for example, trade name “UF-7050” manufactured by Aeroplasma), a fluidized bed type feeder (for example, trade names “4MP”, “5MPE”, “9MP” manufactured by Sulzer Metco) It became possible to manufacture the aluminum nitride member of the present invention by supplying it to a thermal spraying apparatus that cannot produce an output and a high gas flow rate.

  On the other hand, in the production method (2), the average particle size is 1 μm or more and 10 μm or less of the aluminum nitride powder, or the average particle size of 1 μm or more and 10 μm or less of the group IIIA and / or IIA group compound powder and the average particle size of 1 μm or more. A mixed powder of aluminum nitride powder of 10 μm or less is supplied to the outside of the spray gun plasma outlet at two or more locations perpendicular to the plasma jet, and atmospheric pressure plasma is applied under the condition that the spray distance is 40 mm or more and 70 mm or less. It is characterized by spraying.

  A state in which aluminum nitride powder, or a mixed powder of group IIIA and / or group IIA compound powder and aluminum nitride powder is supplied to the outside of the plasma outlet of the thermal spray gun at two or more locations perpendicular to the plasma jet. An example is shown in FIG. The thermal spray raw material powder (121) is supplied using an inert gas (123) such as He by a powder feeder (122). It is bifurcated on the way (124), or is supplied by using two feeders so as to face the plasma jet part (125) at two positions (in the case of FIG. 12). Examples of such a thermal spraying apparatus include thermal spraying apparatuses such as the trade name “SG-100” manufactured by Praxair, and the product names “9MB”, “F4”, and “Triplex” manufactured by Sulzer Metco.

  The supply amount of an inert gas such as He for supplying the molten raw material powder is preferably 5 to 30 SLM. If the supply amount of the inert gas is lower than 5 SLM, it is difficult for fine powder to flow, and if it is higher than 30 SLM, the plasma jet is weakened, and the amount of deposited sprayed film may decrease or the film quality may deteriorate. In addition, the reason for supplying oppositely at two or more locations is that if the powder is supplied only from one direction with respect to the plasma, the powder may penetrate the plasma. This is because it becomes easier to enter the plasma, particularly the center thereof.

  And as a spraying distance, it is preferable to set it as 40-70 mm. When the spraying distance exceeds 70 mm, the sprayed powder is cooled until it adheres to the substrate, and the sprayed film may not be deposited on the substrate. When the spraying distance is shorter than 40 mm, the temperature of both the base material and the sprayed film rises. As a result, cracking of the sprayed film and the substrate, a decrease in nitrogen content in the sprayed film, and a change in composition may occur.

Moreover, as a spraying gas at the time of forming a sprayed film with these spraying apparatuses, it is preferable to use, for example, Ar and / or N ₂ as the main gas and H ₂ as the auxiliary gas. By using H ₂ , the amount of heat of plasma and the speed of the plasma jet are increased, and further, the spraying distance is set to 40 to 70 mm, so that the surface of the sprayed powder to fly and the sprayed powder after deposition become high temperature. Is converted to an oxide, and this oxide is considered to play a role of connecting nitrides. The gas flow rates of Ar and / or N _{2 as the} main gas and H _{2 as} the sub gas vary somewhat depending on the thermal spraying apparatus, but are preferably 60 SLM or more and 1 to 15 SLM, respectively.

  Needless to say, the thermal spray raw material powder containing the lubricant can be applied to the invention of (2).

  The aluminum nitride member of the present invention imparts excellent properties of aluminum nitride to the surface of the member by thermal spraying, so that when used in an electrostatic chuck, heater, plasma processing apparatus chamber in the manufacture of semiconductors, etc., it has high insulation properties. Since it has thermal conductivity and can make the in-plane temperature distribution of the wafer uniform, processing can be performed stably. In addition, when used as a heat dissipation insulating substrate of a power device, an insulating substrate having a large area and a thin insulating layer can be easily provided.

  The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

In addition, the average diameter of the powder which comprises the sprayed film in a following example and a comparative example, the porosity, and the withstand voltage were measured as follows.
(1) Average diameter The diameter of each observable particle | grain was measured from the image observed by observation by 1000-times multiplication factor by SEM of the sprayed film cross section, and the average value was calculated | required.
(2) Porosity The pore portion was traced from an image obtained by observing a cross section of the sprayed film with an SEM at a magnification of 1000 times. The area of the traced pore portion was measured using a product name “Nanohunter” manufactured by Nanosystem. Further, the area of the entire sprayed film including pores was also measured, and the porosity was determined by dividing the area of the pores by the area of the sprayed film.
(3) Dielectric withstand voltage As shown in FIG. 7, an electrode 74 having a diameter of 1 cm is pressed on an aluminum nitride sprayed film 71 using graphite 73 on which an aluminum sprayed film 72 is deposited to a thickness of 100 μm as a spraying base. The dielectric breakdown voltage was measured by gradually increasing the voltage to 5 kV under the conditions of DC and 1 mA using a withstand voltage tester trade name “TOS8750” 75 manufactured by Kikusui Electronics Co., Ltd.

Example 1
An aluminum nitride powder FLC (average particle size of 4.2 μm) manufactured by Toyo Aluminum Co., Ltd. was sprayed onto a quartz glass substrate using a product name “Axial III” spraying apparatus manufactured by Northwest Mettech. As a powder supply, a product name “CPF-2HP” manufactured by German Thermico Co., Ltd. was used.

  As the quartz glass substrate used for thermal spraying, a quartz glass having a surface roughness Ra of 5 μm by blasting and treated with 5% hydrofluoric acid for 2 hours to have a surface roughness Ra of 8 μm was used.

The spraying conditions at this time are normal pressure, spraying distance 100 mm, plasma power 95 kW, Ar, N ₂ and H ₂ gas as spraying gas, 280 SLM, and aluminum nitride powder at a supply rate of 15 g / min. While spraying, the thermal spray gun was moved at a speed of 400 mm / second, and 20-pass thermal spraying was performed. The velocity and temperature of the particles during the thermal spraying were measured with a trade name “DPV-2000” manufactured by Techner of Canada and found to be 590 m / sec and 2250 ° C.

  The deposited thermal spray film has a film thickness of 120 μm and a surface roughness Ra of 9 μm. In the analysis of the constituent phases by the X-ray diffraction method, hexagonal aluminum nitride and γ aluminum oxide are observed, and hexagonal aluminum nitride (100 ) Plane and γ aluminum oxide (400) plane X-ray diffraction peak intensity ratio was 0.11. Further, when the cross section of this sprayed film was observed by SEM, it was composed of spherical particles having an average diameter of about 4 μm, and the porosity of the image subjected to the cross section SEM observation was measured by an image analysis method. However, the porosity was 27%.

Example 2
Thermal spraying was performed under the same conditions as in Example 1 except that the plasma gas flow rate was changed to 100 to 280 L / min, the output was changed to 60 to 130 kW, and the thermal spray distance was changed to 60 to 140 mm. The velocity, the sprayed film thickness, and the peak intensity ratio of hexagonal aluminum nitride were measured. As shown in FIG. 8, the film thickness of the sprayed film increases with an increase in the powder temperature during the flight, but when the temperature exceeded 2280 ° C., the proportion of aluminum oxide increased and the proportion of hexagonal aluminum nitride decreased rapidly. On the other hand, when the temperature was lower than 2200 ° C., the deposition of the sprayed film was small.

Example 3
Graphite with a blasted surface and an aluminum sprayed film deposited at 100 μm is used as the thermal spray base, and aluminum nitride powder and yttrium oxide with different mixing ratios as the powder used for thermal spraying (4N, yttrium made in Japan, average particle size 4 μm) Alternatively, a mixed powder with magnesium oxide (2N made by high-purity chemical, average particle size 4 μm) was sprayed under the same conditions as in Example 1. About this sprayed film, the amount of yttrium oxide or magnesium oxide in the sprayed film is measured by fluorescent X-ray analysis, the porosity of the image obtained by observing the cross-sectional SEM of the sprayed film is measured by an image analysis method, and ULVAC-RIKO Co., Ltd. The thermal conductivity was measured by the product name “LaserPIT”. The results are shown in Table 1. The content of yttrium oxide in the sprayed film is 7 to 30% by weight, the content of magnesium oxide is 8% by weight, the porosity is 11% to 13%, and the peak intensity ratio of hexagonal aluminum nitride is 0.11 to 0.12. The thermal conductivity was 11 to 46 W / mK. Each sprayed coating was composed of spherical particles having an average diameter of about 4 μm. FIG. 9 shows an SEM image of a cross section of the sprayed film having an yttrium oxide content of 7% by weight. FIG. 10 shows the distribution of Al, N, and Y by EPMA on the cross section of the sprayed film having an yttrium oxide content of 30%. It is confirmed that there is a portion where the Y concentration is high in the gap between the particulate Al and N, and yttrium oxide is present in the gap between the aluminum nitride particles.

Example 4
Surfaces of the quartz bell jar 111 and the ring insulating base 112 of the plasma cleaning apparatus shown in FIG. 11 were blasted to 7, 6, and 3 μm, respectively. Using the same aluminum nitride powder and yttrium oxide powder as in Example 3, the mixture ratio of yttrium oxide powder was set to 2 wt%, and only the number of passes was set to 15, and thermal spraying was performed under the same conditions as in Example 1 to obtain an average spray. An aluminum nitride sprayed member having a thickness of 90 μm was obtained. The surface roughness of the bell jar 111 and the ring insulating base 112 was 8, 7, and 4 μm, respectively. These members and other necessary members were ultrasonically cleaned with ultrapure water, dried in a clean oven, and set in a chamber of a plasma cleaning apparatus.

Example 5
As a base material, a trade name “Alsink A-SC60” manufactured by Denki Kagaku Kogyo Co., Ltd., which is an aluminum-silicon carbide composite, is prepared, and an aluminum nitride sprayed film having an yttrium oxide content of 7 wt% shown in Table 1 is applied to the surface. It was produced under the same conditions as in Example 1.

  As a sealing agent for this aluminum nitride sprayed film, a product name “Permeate HS-100 Clear” manufactured by D & D Co., Ltd., which is composed of an alkoxysilane compound made of silicon resin, an epoxy resin and a curing agent Sealed with a product made by Pernox Co., Ltd., trade name “Pernox WE-1263” and “Percure HV-126”, polysilazane which is a silica coating agent, made by Clariant Japan Co., Ltd., trade name “AQUAMICA” went.

  As for the sealing method, in case of Permeate HS-100 Clear, it was allowed to stand at room temperature after being immersed in a vacuumed sample. Time curing was performed. In AQUAMICA, spraying was performed on the surface of the sprayed film, followed by drying and curing at 150 ° C. for 1 hour, and the process from spraying to curing was performed twice. The porosity of this pre-sealing sample was 10%, but the pores disappeared after sealing.

  The sealed aluminum nitride sprayed film and the non-sealed aluminum nitride sprayed film were polished to have a film thickness of 200 μm, and then the dielectric strength test was performed. The performance of the dielectric strength tester was up to 5 kV, but all the samples subjected to sealing exceeded 5 kV and were 0.25 MV / cm or more. The insulation breakdown voltage of the non-sealed aluminum nitride sprayed film was 0.16 MV / cm.

Example 6
Adds 0, 0.3, 2, 4, 6 wt% of stearic acid as a lubricant to the mixed powder of 90 wt% aluminum nitride powder and 10 wt% yttrium oxide (4N made in Japan, average particle size 4 μm) Then, thermal spraying raw material powders mixed with a dry ball mill were prepared, and a supply test was performed using a trade name “5MPE” manufactured by Sulzer Metco and flowing He at 25 L / min as a feed gas. Further, a sprayed coating was prepared under the same conditions as in Example 1. As the evaluation method of supplyability, confirmation was made as to whether there was any change in the flow rate of the powder being supplied (pulsation), and continuity of the supply of powder was used. In addition, the appearance of the sprayed film was observed. The results are shown in Table 2.

  All the powders to which stearic acid was added did not change in the powder flow rate, and the continuity of supply could be confirmed, and supply for 10 minutes or more was possible. Occasional pulsations were observed in the powder without the addition of stearic acid. The sprayed film using the powder added with 6 wt% stearic acid had a light brown color.

Example 7
A powder supply test was performed in the same manner as in Example 6 except that 1 wt% of paraffin (melting point: 68 to 70 ° C.) was used as the lubricant. The powder to which paraffin was added did not change in the powder flow rate, and the continuity of supply could be confirmed, and supply for 10 minutes or more was possible.

Example 8
1 wt% of stearic acid is added to a mixed powder of 90 wt% aluminum nitride powder and 10 wt% yttrium oxide (4N made by Japan yttrium, average particle size 4 μm), and the powder mixed by a dry ball mill is used as a spraying raw material powder As described above, thermal spraying was performed on a quartz glass substrate using a product name “F4” spraying device manufactured by Sulzer Metco. As the supply of powder, the product name “5MPE” manufactured by Sulzer Metco is used, and He gas is supplied as a feed gas at 25 L / min, and the mixed powder of aluminum nitride powder, yttrium oxide and stearic acid is supplied at 24 g / min. The counter flow was supplied at two locations to the spray gun outlet.

As spraying conditions, the spraying distance was 50 mm, the plasma gas was Ar: 60 SLM, H ₂ : 0, 5, 10, 13, 15 SLM, and 20-pass spraying was performed while moving the spray gun at a speed of 400 mm / sec. . The results are shown in Table 3. Although the film adhered at all H ₂ gas flow rates, the film adhesion was weak at 0 SLM, and protrusions occurred on the surface of the sprayed film at 15 SLM.

Example 9
Thermal spraying was performed under the same conditions as in Example 8 except that the H ₂ gas flow rate was 10 SLM and the thermal spray distance was 40 to 80 mm. The results are shown in Table 4. At a spraying distance of 80 mm, the adhesion of the sprayed film was weak, but the others were good.

Comparative Example 1
An aluminum nitride powder having an average particle size of 15 μm (aluminum nitride powder FLX (average particle size: 18.1 μm) manufactured by Toyo Aluminum Co., Ltd.) was sprayed under the same conditions as in Examples 1 and 2, but the sprayed film adhered. I did not.

Comparative Example 2
Surfaces of the quartz bell jar and ring insulating base of the plasma cleaning device were blasted to 7, 6, and 3 μm, respectively. These members and other necessary members were ultrasonically cleaned with ultrapure water, dried in a clean oven, and set in a chamber of a plasma cleaning apparatus.

Continuous use test of members of Example 4 and Comparative Example 2 When the chamber plasma cleaning apparatus of Example 4 and Comparative Example 2 was continuously used in the semiconductor manufacturing process, in Comparative Example 2, particles increased after 3 days. 4 and 20 days later, the particles increased and members such as bell jars and ring insulation bases were taken out and replaced. The particle reduction effect of the aluminum nitride sprayed member of the present invention was shown.

It is a figure which shows an example of the schematic diagram of an aluminum nitride spraying member. It is a figure which shows an example of the schematic diagram of an aluminum nitride spraying member. It is a figure which shows an example of the X-ray-diffraction chart of an aluminum nitride sprayed film. It is a figure which shows an example of a structure of the heater of an aluminum nitride spraying member, and an electrostatic chuck. It is a figure which shows an example of a structure of the thermal radiation insulation board | substrate of an aluminum nitride spraying member. It is a figure which shows an example of a withstand voltage test. It is a figure which shows an example of a plasma spraying apparatus. It is a figure which shows the temperature of the aluminum nitride particle in flight, the adhesion efficiency of a sprayed film, and the peak intensity ratio of hexagonal aluminum nitride. It is a SEM image of the cross section of the produced aluminum nitride sprayed film. It is the Al, N, Y composition image by EPMA of the cross section of the produced aluminum nitride sprayed film. It is a figure which shows an example of the outline of a plasma cleaning apparatus. It is a figure which shows an example of the aspect which supplies a thermal spray raw material powder facing two places with respect to a plasma jet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11: Base material 12: Thermal spray film 13: Aluminum nitride particle 21: Base material 22: Thermal spray film 23: Aluminum nitride particle 24: IIIA group and / or IIA group compound 41: Metal base material 42: 1st thermal spray film 43: Metal electrode film or heater layer 44: Second sprayed film 51: Metal heat dissipation base material 52: Aluminum nitride sprayed film 53: Metal plating or sprayed film 54: Solder 55: Power device 60: Cathode 61: Anode 62: Plasma gas 63 : Thermal spray powder (supply port)
64: Convergence 65: Spraying distance 66: Substrate 67: Sprayed film 68: Power supply 111: Bell jar 112: Ring insulating base 113: Silicon wafer 114: Ar ion 115: Deposit by Ar ion sputtering 116: Antenna power high frequency power supply 117 : High frequency coil 118: Bias power high frequency power supply 121: Spraying raw material powder 122: Powder supply machine 123: Inert gas cylinder 124: Bifurcated 125: Plasma jet 126: Thermal spray gun

Claims (24)

An aluminum nitride sprayed member in which a sprayed film made of substantially spherical aluminum nitride particles having an average diameter of 1 μm or more and 10 μm or less is formed on a substrate. An aluminum nitride sprayed member in which a sprayed film made of a substantially spherical aluminum nitride particle having an average diameter of 1 μm or more and 10 μm or less and a group IIIA and / or a group IIA compound is formed on a substrate. The aluminum nitride sprayed member according to claim 2, wherein a group IIIA and / or a group IIA compound exists in the gap between the aluminum nitride particles, and the porosity of the sprayed film is 15% or less. The aluminum nitride sprayed member according to claim 2 or 3, wherein the content of the group IIIA and / or group IIA compound in the sprayed film is 1 wt% or more and 30 wt% or less. The aluminum nitride sprayed member according to any one of claims 1 to 4, wherein the surface of each aluminum nitride particle is oxidized and bonded to adjacent particles. In the X-ray diffraction peak intensity of the sprayed film, the ratio of the sum of the peak intensity of the γ aluminum oxide (400) plane and the α aluminum oxide (104) plane to the peak intensity of the aluminum nitride (100) plane is 0.05 or more and 0.00. The aluminum nitride sprayed member according to claim 5, wherein the number is 2 or less. A thermal spray member in which at least a first thermal spray film, a metal electrode layer or a heater layer, and a second thermal spray film are formed in this order on a substrate, and the first thermal spray film and / or the second thermal spray film are provided. An aluminum nitride sprayed member comprising a sprayed film made of substantially spherical aluminum nitride particles having an average diameter of 1 μm to 10 μm. A thermal spray member in which at least a first thermal spray film, a metal electrode layer or a heater layer, and a second thermal spray film are formed in this order on a substrate, and the first thermal spray film and / or the second thermal spray film are provided. A sprayed aluminum nitride member, characterized in that it is a sprayed film composed of substantially spherical aluminum nitride particles having an average diameter of 1 μm or more and 10 μm or less and a group IIIA and / or a group IIA compound. 9. The aluminum nitride sprayed member according to claim 8, wherein a group IIIA and / or a group IIA compound is present in the gap between the aluminum nitride particles, and the porosity of the sprayed film is 15% or less. The aluminum nitride sprayed member according to claim 8 or 9, wherein the content of the group IIIA and / or group IIA compound in the sprayed film is 1 wt% or more and 30 wt% or less. The aluminum nitride sprayed member according to any one of claims 7 to 10, wherein the surface of each aluminum nitride particle is oxidized and bonded to an adjacent particle. In the X-ray diffraction peak intensity of the sprayed film, the ratio of the sum of the peak intensity of the γ aluminum oxide (400) plane and the α aluminum oxide (104) plane to the peak intensity of the aluminum nitride (100) plane is 0.05 or more and 0.00. The aluminum nitride sprayed member according to claim 11, wherein the number is 2 or less. The aluminum nitride sprayed member according to any one of claims 1 to 12, wherein an aluminum nitride sprayed film is formed on a portion exposed to the plasma. 10. The aluminum nitride sprayed member according to claim 2, 8 or 9, wherein a sprayed film made of aluminum nitride and a group IIIA and / or a group IIA compound is formed on a portion exposed to plasma. . The aluminum nitride sprayed member according to claim 13 or 14, wherein the aluminum nitride sprayed member has a dome shape, a cylinder shape, or a ring shape, and a surface roughness Ra of the aluminum nitride sprayed film is not less than 1 µm and not more than 15 µm. Thermal spray member. The substrate is a metal or metal-ceramic composite heat dissipation substrate having a thermal conductivity of 100 W / mK or more, and the aluminum nitride sprayed film has a thermal conductivity of 10 W / mK or more. The aluminum nitride thermal spray member according to any one of the above. The aluminum nitride sprayed member according to any one of claims 1 to 16, wherein the aluminum nitride sprayed film is sealed. The aluminum nitride sprayed member according to any one of claims 1 to 17, wherein the insulation breakdown voltage of the aluminum nitride sprayed film is 0.15 MV / cm or more. Aluminum nitride powder having an average particle diameter of 1 μm or more and 10 μm or less is supplied to the thermal spraying apparatus, and the average temperature of the aluminum nitride particles immediately before the substrate is 2200 ° C. or more and 2280 ° C. or less, and the average flight speed is 400 m / s or more and 600 m / s or less. 8. The method for producing an aluminum nitride sprayed member according to claim 1 or 7, wherein an aluminum nitride sprayed film is formed on the substrate by atmospheric pressure plasma spraying under the following conditions. A group IIIA and / or group IIA compound powder having an average particle size of 1 μm to 10 μm and an aluminum nitride powder having an average particle size of 1 μm to 10 μm are supplied to the thermal spraying apparatus, and the average temperature of the aluminum nitride particles is just before the substrate. The aluminum nitride sprayed film is formed on the substrate by atmospheric pressure plasma spraying under the conditions of 2200 ° C or higher and 2280 ° C or lower and an average flight speed of 400m / s or higher and 600m / s or lower. The manufacturing method of the aluminum nitride thermal spray member of Claim 8. An aluminum nitride powder having an average particle size of 1 μm or more and 10 μm or less, and a mixed powder obtained by adding a lubricant of 0.1 to 5 wt% with respect to the weight of the aluminum nitride powder is supplied to the thermal spraying apparatus as a thermal spraying powder. The method for producing an aluminum nitride sprayed member according to claim 1 or 7, wherein an aluminum nitride sprayed film is formed on the substrate by plasma spraying. Group IIIA and / or Group IIA compound powder having an average particle size of 1 μm to 10 μm, aluminum nitride powder having an average particle size of 1 μm to 10 μm, and 0.1 to 5 wt% of the total weight of these powders 9. The aluminum nitride according to claim 2, wherein the mixed powder to which the lubricant is added is supplied as a thermal spray powder to a thermal spraying apparatus, and an aluminum nitride sprayed film is formed on the substrate by atmospheric pressure plasma spraying. Manufacturing method of thermal spray member. An aluminum nitride powder having an average particle size of 1 μm or more and 10 μm or less is supplied to the outside of the plasma outlet of the spray gun at two or more locations perpendicular to the plasma jet, and atmospheric pressure is applied under the condition that the spray distance is 40 mm or more and 70 mm or less. The method for producing an aluminum nitride sprayed member according to claim 1 or 7, wherein an aluminum nitride sprayed film is formed on the substrate by plasma spraying. A mixed powder of a group IIIA and / or group IIA compound powder having an average particle size of 1 μm to 10 μm and an aluminum nitride powder having an average particle size of 1 μm to 10 μm is perpendicular to the plasma jet outside the plasma outlet of the spray gun. The aluminum nitride sprayed film is formed on the substrate by atmospheric pressure plasma spraying under the condition that the spraying distance is 40 mm or more and 70 mm or less. The manufacturing method of the aluminum nitride spraying member as described in any one of.

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