JP2008156160A - Corrosion resistant member and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that in the case when a corrosion resistant member, used for a semiconductor manufacturing apparatus for plasma CVD or the like, has an uneven part on its surface, the efficiency of film deposition of a semiconductor wafer is reduced because a plasma generated in the semiconductor manufacturing apparatus is made unstable by edge effect and thereby, the etching rate becomes unstable. <P>SOLUTION: A corrosion resistant member is made of an oxide ceramic sintered compact and is characterized in that the arithmetical average height (Ra) on the surface, exposed to a halogen-based corrosive gas or a plasma of the gas, is ≤3 μm, the average crystal grain diameter of the oxide ceramic sintered compact is 1-50 μm, and the skewness (Rsk) obtained from the roughness curve of the surface is within a range of -1.0 to +0.5. Since a plasma generated in a semiconductor manufacturing apparatus is dispersed to uneven parts of the surface of the sintered compact, and the edge effect having an affect on the stability is reduced, the etching rate is stabilized in a short time and the efficiency of film deposition of the semiconductor wafer can be improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a corrosion-resistant member used in a semiconductor manufacturing apparatus, and more particularly to a corrosion-resistant member used in a portion exposed to a halogen-based corrosive gas or plasma thereof.

  Conventionally, ceramics have been used as a member having high corrosion resistance in a halogen-based corrosive gas or a part exposed to the plasma in a semiconductor manufacturing apparatus such as a plasma CVD apparatus.

  Examples of the ceramic used as the corrosion-resistant member include oxide ceramic sintered bodies such as alumina, yttrium / aluminum / garnet, and yttria. Any of such oxide ceramic sintered bodies has a high melting point and boiling point of a halogen-based corrosive gas or a halide produced by a reaction thereof with plasma, and is excellent in corrosion resistance because the progress of corrosion can be delayed.

  However, since plasma used in a plasma CVD apparatus or the like is active, even when an oxide ceramic sintered body having excellent corrosion resistance is corroded, particles accompanying the generation of halide are generated. The particles were accelerated by an electric field when the halogenated corrosive gas or the halide produced by reaction upon exposure to the plasma was peeled off and deposited by repeated evaporation and solidification. It is considered that ions are generated by ion bombardment incident on the halide. Since these particles cause defects in the manufacture of semiconductors, there is a need for corrosion resistant members that are less likely to generate particles.

  In response to this requirement, for example, Patent Document 1 discloses a member for a semiconductor manufacturing apparatus used in a semiconductor manufacturing apparatus that performs processing using a corrosive gas, having a porosity of 10% or less and a surface roughness. A member for a semiconductor manufacturing apparatus made of a ceramic sintered body with an Ra of more than 1 μm has been proposed. In such a member for semiconductor manufacturing equipment, the unevenness on the surface of the member brings about an anchor effect on the halogenated film and precipitates generated on the surface, so that sufficient corrosion resistance is maintained against the halogen-based corrosive gas and its plasma. However, the halogenated film and precipitates are difficult to peel off, and the generation of particles can be reduced.

Moreover, in patent document 2, the surface of the base material which consists of dense ceramics with a purity of 95% or more is formed in the rounded 1st unevenness | corrugation whose surface roughness Ra is 3-40 micrometers, and this 1st A ceramic member having a rough surface in which the surface of the unevenness is formed into a second unevenness having a round surface roughness Ra of 0.1 to 2.9 μm has been proposed. According to the ceramic member having the rough surface, the total surface area is obtained by adding the surface area of the first unevenness and the surface area of the second unevenness, and the directing direction of the second unevenness is that of the substrate. Some of them do not point to the original surface, and all the surfaces are rounded, so that an extremely excellent anchor effect is exhibited and particles can be reduced as compared with the prior art.
JP 2000-247726 A JP 2003-171190 A

  However, the member for a semiconductor manufacturing apparatus disclosed in Patent Document 1 or 2 has an infinite number of uneven portions on or formed on the surface of the member in order to prevent the falling of a halogenated film or precipitates that become particles. It has been clarified that the projections (edges) formed by the uneven portions affect the stability of plasma generated in the semiconductor manufacturing apparatus. Particularly in recent years, with the advancement of semiconductor technology, the diameter of a semiconductor wafer has been increased from 8 inches to 12 inches, and it is necessary to generate more stable plasma and perform highly accurate etching in a short time.

  Therefore, when the conventional semiconductor manufacturing apparatus members described in Patent Documents 1 and 2 are used in a semiconductor manufacturing apparatus such as plasma CVD, the plasma generated in the apparatus is not stable and requires a long-time break-in operation. There was a possibility that the delay of the film process and high-precision etching could not be performed stably in a short time. In particular, if there are very sharp peaks or deep valleys in the roughness curve of the surface of the corrosion-resistant member in the initial stage of plasma generation by applying a high frequency, the plasma is not stable and the etching rate varies greatly. Because of this, long running-in operation is carried out until the very sharp peaks and deep valleys seen in the roughness curve of the surface of the corrosion-resistant member are corroded, or until it becomes smooth due to adhesion of halogenated film and precipitates. There is a problem that a long running-in operation is required. Thus, there is a problem that the implementation of the film forming process after the etching process is delayed and the production efficiency in the semiconductor manufacturing process is remarkably lowered.

  The present invention has been devised to solve the above problems, and provides a corrosion-resistant member capable of ensuring a stable etching rate in a short time without the need for a long-term break-in operation and a method for manufacturing the same. For the purpose.

  The corrosion-resistant member of the present invention is a corrosion-resistant member comprising an oxide ceramic sintered body and having an arithmetic average height (Ra) of a surface exposed to a halogen-based corrosive gas or plasma thereof of 3 μm or less. The average crystal grain size of the ceramic sintered body is 1 to 50 μm, and the skewness (Rsk) obtained from the surface roughness curve is in the range of −1.0 to +0.5. .

  Moreover, the corrosion-resistant member of the present invention is characterized in that, in the above configuration, the kurtosis (Rku) determined from the surface roughness curve of the oxide ceramic sintered body is 3.0 to 4.5.

  Furthermore, the corrosion-resistant member of the present invention is characterized in that, in any one of the above structures, the oxide ceramic sintered body is made of alumina, yttria, or a composite material of alumina, yttrium, aluminum, and garnet.

  The method for producing a corrosion-resistant member of the present invention includes a step of mixing a ceramic material, a binder, and a solvent to obtain a secondary raw material, and filling the secondary raw material in a mold in any one of the above configurations. And a step of obtaining a molded body in which the surface roughness of the mold is transferred to the surface, and a maximum temperature of 1550 to 1700 ° C. is maintained for 2 hours or more in air or an oxidizing atmosphere, and then the maximum temperature is 1000 5 to 20 ° C./hour from 1000 ° C., 20 to 50 ° C./hour from 1000 ° C. to 500 ° C., and 50 to 100 ° C./hour from 500 ° C. to room temperature. Is.

  According to the corrosion-resistant member of the present invention, the corrosion-resistant member comprises an oxide ceramic sintered body, and has an arithmetic average height (Ra) of a surface exposed to a halogen-based corrosive gas or plasma thereof of 3 μm or less, The oxide ceramic sintered body has an average crystal grain size of 1 to 50 μm and a skewness (Rsk) determined from the roughness curve of the surface in the range of −1.0 to +0.5. Innumerable irregularities (edges) exist or are formed on the surface, and the plasma generated in the semiconductor manufacturing apparatus is dispersed by the irregularities to reduce the edge effect that affects the stability. When the member is used as a corrosion-resistant member for a plasma CVD apparatus, the etching rate can be stabilized in a short time, so the initial stage of generating plasma by applying a high frequency Can implement stable etching from floor, for the subsequent deposition can be carried out, it is possible to improve production efficiency in the semiconductor manufacturing process.

  Further, according to the corrosion-resistant member of the present invention, the surface of the corrosion-resistant member is smoother than before by using a corrosion-resistant member having a kurtosis (Rku) of 3.0 to 4.5 determined from the surface roughness curve of the ceramic sintered body. Since the edge effect that affects the stability of the plasma can be further reduced, the etching rate of the semiconductor wafer surface can be stabilized in a shorter time and the production efficiency in the semiconductor manufacturing process can be improved. It becomes possible.

  Furthermore, according to the corrosion-resistant member of the present invention, the ceramic sintered body is made of alumina, yttria, or a composite material of alumina and yttrium, aluminum, and garnet, so that the melting point and boiling point of the halide generated by the reaction with plasma can be reduced. Since it is high and the progress of corrosion can be delayed, a corrosion resistant member having sufficient corrosion resistance can be obtained.

  According to the method for producing a corrosion-resistant member of the present invention, the corrosion-resistant member is formed by mixing a ceramic material, a binder, and a solvent to obtain a secondary raw material, and filling the secondary raw material in a mold. , A step of obtaining a molded body in which the surface roughness of the mold is transferred to the surface, and a maximum temperature of 1550 to 1700 ° C. is maintained for 2 hours or more in air or an oxidizing atmosphere, and then the maximum temperature is 1000 ° C. 5 to 20 ° C / hour, 20 to 50 ° C / hour from 1000 ° C to 500 ° C, and a method of lowering the temperature from 500 ° C to room temperature at a rate of 50 to 100 ° C / hour. The blasting pattern has been used in the past because of the firing pattern that transfers the smoother surface of the plastically deformable metal mold to the surface of the ceramic body and promotes more uniform grain growth of the ceramic particles to maintain the surface. And after firing such as various grinding and polishing processes The manufacturing method that has obtained a predetermined surface roughness by the process of the present invention of each of the above configurations having a surface state that is smoother and has fewer edges as compared to the surface by the manufacturing method obtained by processing and firing the molded body. It becomes possible to obtain a corrosion-resistant member. Furthermore, by making the temperature lowering time from the maximum firing temperature longer than before, it is possible to promote the grain growth of the ceramic particles especially near the surface of the corrosion-resistant member, so that the smooth surface state with less uneven parts and Thus, the corrosion-resistant member of the present invention can be manufactured.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The corrosion-resistant member of the present invention is a corrosion-resistant member comprising an oxide ceramic sintered body and having an arithmetic average height (Ra) of a surface exposed to a halogen-based corrosive gas or plasma thereof of 3 μm or less. The sintered body has an average crystal grain size of 1 to 50 μm and a skewness (Rsk) determined from a surface roughness curve within a range of −1.0 to +0.5.

Here, the halogen-based corrosive gas is used in a semiconductor manufacturing apparatus such as a plasma CVD apparatus, and is a fluorine-based gas such as SF ₆ , CF ₄ , CHF ₃ , ClF ₃ , HF, Cl ₂ , HCl, Examples include chlorine-based gases such as BCl ₃ , bromine-based gases such as Br ₂ , HBr, and BBr _3, and iodine-based gases. These gases are turned into plasma by inducing microwaves or high-frequency waves into the atmosphere in which these gases are introduced, or by applying a potential difference equal to or higher than the dissociation voltage of the gases. After etching or cleaning the surface of the wafer, a protective film such as a nitride film or an oxide film is formed on the semiconductor wafer. The corrosion-resistant member of the present invention has excellent corrosion resistance even when its surface is exposed to these halogen-based corrosive gases or plasma thereof.

  In addition, the corrosion resistant member of the present invention has excellent corrosion resistance, and its surface state does not affect the stability of plasma generated in the semiconductor manufacturing apparatus. The conventional corrosion-resistant member has a surface anchoring effect on the deposit deposited on the surface of the corrosion-resistant member in the semiconductor manufacturing apparatus, and prevents the generation of particles due to the fall of the deposit. However, with the corrosion resistant member having such a surface state, the plasma generated in the semiconductor manufacturing apparatus is not stable, and the etching rate when etching the surface of the semiconductor wafer is stable. It was difficult to do. The cause of this is thought to be due to the edge effect in which the plasma is dispersed by the edges of very sharp peaks and deep valleys seen in the roughness curve of the surface of the corrosion-resistant member, but the true cause is obvious It is not. Although the cause is not clear, the corrosion resistant member of the present invention has a surface state capable of eliminating such plasma instability.

  More specifically, the arithmetic average height (Ra) of the surface is 3 μm or less, the average crystal grain size is 1 to 50 μm, and the skewness (Rsk) determined from the roughness curve of the surface ) Is -1.0 to +0.5.

  Here, the reason that the arithmetic average height (Ra) of the surface of the corrosion-resistant member of the present invention is 3 μm or less is that the uneven portion that can be the edge of the surface of the corrosion-resistant member, which is considered to affect the stability of the plasma, In comparison, it is possible to reduce the average, and by applying a high frequency, stable plasma is generated from the initial stage, the etching rate stability can be ensured, and the surface of the corrosion resistant member and the halogen system in the semiconductor manufacturing apparatus This is because the contact area with the corrosive gas can be reduced, and the corrosion resistance of the corrosion resistant member can be improved. When the arithmetic average height (Ra) of the surface is larger than 3 μm, the height of the uneven portion on the surface of the corrosion resistant member is inevitably increased as a whole, and an edge portion that is considered to affect the plasma is formed. It becomes easy and is not preferable. When trying to obtain an etching rate capable of stably etching up to the bottom of the groove formed on the surface of the semiconductor wafer for baking the circuit pattern on the IC chip manufactured from the semiconductor wafer, the surface of the corrosion-resistant member The arithmetic average height (Ra) is more preferably 1 μm or less. The arithmetic average height (Ra) of the surface is measured using a commercially available contact type or non-contact type surface roughness meter and attached to JIS standards (JIS B 0601-2001, JIS B 0633-2001, JIS B 0031-2003). For example, when the arithmetic average height Ra is estimated to be greater than 0.1 μm and 2 μm or less, the evaluation length is set to 4 mm and the cutoff value (reference length) is set to 0.8 mm. It can be measured under conditions.

  In addition, the average crystal grain size of the corrosion-resistant member of the present invention is in the range of 1 to 50 μm because the plasma is stable from the initial stage by applying a high frequency while maintaining corrosion resistance and mechanical characteristics equal to or higher than conventional ones. This is to obtain a corrosion-resistant member that can stabilize the etching rate. If the average crystal grain size is less than 1 μm, when the surface of the corrosion-resistant member is corroded, it is likely to be corroded from the grain boundaries. Therefore, when the average crystal grain size is larger than 50 μm, the strength of the corrosion-resistant member itself is significantly reduced. It is not preferable.

  The average crystal grain size was measured by preparing a test piece cut out from a corrosion-resistant member, and further removing the grain boundary composition of the alumina crystal by chemically or heat treating the observation surface to remove the grain boundary composition of the alumina crystal. A photograph was taken with a scanning electron microscope (SEM) at a magnification of 10 and arbitrarily selected 10 crystal grains from the photographic image, and the maximum length of each crystal grain was defined as the crystal grain size. The average of the measured values is the average crystal grain size.

  Furthermore, the reason why the skewness (Rsk) of the corrosion-resistant member of the present invention is set within the range of -1.0 to +0.5 is to reduce the overall height of the uneven portions present on the surface of the corrosion-resistant member. Skewness indicates the degree of unevenness of the surface of the corrosion-resistant member being biased to peaks or valleys. If the peaks or valleys are biased, that portion is generated in the semiconductor manufacturing apparatus. It is thought that it affects the stability of the plasma and affects the stability of the etching rate. A detailed description of the skewness (Rsk) is shown below. The skewness (Rsk) will be described in detail based on JIS B 0601-2001.

  FIG. 1 is an explanatory diagram of the nature of skewness (Rsk), where (a) is a roughness curve and probability density function when skewness (Rsk) takes a positive value, and (b) is a negative skewness (Rsk). (C) is the roughness curve and probability density function when the skewness (Rsk) value approaches zero.

  As shown in FIG. 1A, in the case of a roughness curve in which the valley portion is wide with respect to the mountain, the probability density function has a distribution shape biased toward the valley, and the value of the skewness (Rsk) is larger than 0. Shows a positive value. On the other hand, when the peak portion is a relatively flat roughness curve as shown in FIG. 1B, the probability density function is biased toward the peak side, and the value of the skewness (Rsk) becomes smaller than 0 and becomes a negative value. Show. These corrosion-resistant members having a surface with a roughness curve as shown in FIGS. 1 (a) and 1 (b) affect the plasma due to the edge effect of the uneven portions on the surface, and the etching rate is difficult to stabilize. It is considered a thing.

  Therefore, the surface of the corrosion-resistant member of the present invention should have a skewness (Rsk) value of the roughness curve in the range of −1.0 to +0.5. When the value of the skewness (Rsk) is smaller than −1.0, as shown in FIG. 1B, the peak portion becomes a relatively flat roughness curve, and when the value is larger than +0.5, the value of FIG. As shown in a), the valley portion has a wide roughness curve with respect to the mountain. In such a roughness curve, peaks and valleys having different heights and depths become edges, and this edge effect is considered to be a factor destabilizing plasma generated in the semiconductor manufacturing apparatus, which is not preferable. On the other hand, when the value of skewness (Rsk) is −1.0 to +0.5 as in the corrosion resistant member of the present invention, the roughness curve as shown in FIG. It will be close to. If the surface state of the corrosion resistant member is such that such a roughness curve is obtained, the plasma generated in the semiconductor manufacturing apparatus is hardly affected by the edge effect, and a stable etching rate can be obtained. More preferably, it should be in the range of −0.5 to +0.5, and then the probability density function of the roughness curve will be closer to a normal distribution, and there will be no bias on either the mountain side or the valley side. It is considered that the influence on plasma is also reduced. In the probability density function of the roughness curve, the occurrence of a bias on either the peak side or the valley side means that there is a sharp edge that is thought to affect the stability of the plasma, and this is prevented. It is preferable to approximate a normal distribution state with no bias.

  For skewness (Rsk), a commercially available contact-type or non-contact-type surface roughness meter is used, and JIS standards (JIS B 0601-2001, JIS B 0633-2001, JIS B 0031-2003, Appendix G, F). For example, when the arithmetic average height Ra is estimated to be greater than 0.1 μm and 2 μm or less, the measurement should be performed under the setting conditions where the evaluation length is 4 mm and the cutoff value (reference length) is 0.8 mm. Can do.

  Further, the corrosion-resistant member of the present invention preferably has a kurtosis (Rku) of 3.0 to 4.5 determined from the surface roughness curve of the oxide ceramic sintered body.

  Here, details of Kurtosis (Rku) will be described based on JIS B 0601-2001.

  FIG. 2 is an explanatory diagram of the nature of kurtosis (Rku), (a) is a roughness curve and probability density function when kurtosis (Rku) is greater than 3, and (b) is kurtosis (Rku) from 3. It is a roughness curve and probability density function when it becomes small.

  As shown in FIG. 2 (a), in the roughness curve having very sharp peaks and deep valleys, the distribution form of the probability density function is sharp, and the value of Kurtosis (Rku) in this case is larger than 3. Become. On the other hand, as shown in FIG. 2B, in the roughness curve composed of gentle peaks and valleys, the distribution form of the probability density function is gentle and the value of kurtosis (Rku) is smaller than 3.

  The corrosion-resistant member of the present invention can be a corrosion-resistant member in which the influence of the edge effect on the plasma is further reduced by setting the kurtosis (Rku) value obtained from the roughness curve of the surface within the range of 3.0 to 4.5. A stable etching rate can be obtained. If the value of this kurtosis (Rku) is less than 3.0, the surface of the corrosion-resistant member has no very sharp peaks or deep valleys, and although a better surface state is obtained for plasma stabilization, an extremely smooth surface Therefore, the deposits adhering to the surface of the corrosion-resistant member are extremely easy to fall, which is not preferable because the particles are extremely increased. In addition, when the value of kurtosis (Rku) is greater than 4.5, more sharp peaks and deep valleys are formed on the surface of the corrosion-resistant member. Therefore, the corrosion-resistant member having such a surface is used as an apparatus such as a plasma CVD apparatus. When used as a member for semiconductor manufacturing equipment that generates plasma inside, the plasma generated by the edge effect of very sharp peaks and deep valleys becomes difficult to stabilize, and the etching rate on the surface of the semiconductor wafer becomes unstable It is not preferable.

  Note that the kurtosis (Rku) is 3 when the probability density function follows a normal distribution. The corrosion-resistant member of the present invention has a surface kurtosis (Rku) in the range of 3.0 to 4.5, so that the distribution form of the probability density function approaches a normal distribution, and the surface of the member affects the plasma stability. There are very few sharp points and deep valleys that give

  This kurtosis (Rku) uses a commercially available contact type or non-contact type surface roughness meter and conforms to JIS standards (JIS B 0601-2001, JIS B 0633-2001, JIS B 0031-2003 appendices G and F). In conformity, for example, when the arithmetic average height Ra is estimated to be greater than 0.1 μm and 2 μm or less, the measurement may be performed under the setting conditions where the evaluation length is 4 mm and the cutoff value (reference length) is 0.8 mm. it can.

The corrosion-resistant member of the present invention is mainly composed of an oxide ceramic sintered body. In particular, among oxide ceramics, it is preferable to be composed of a composite material of alumina or yttria or alumina and yttrium aluminum garnet (hereinafter referred to as YAG), which is excellent in corrosion resistance to halogen-based corrosive gas or plasma thereof. When these materials come into contact with halogen-based corrosive gas or plasma thereof, reaction products with contact gas such as fluoride such as AlF ₃ and YF ₃ are generated on the surface, but their melting point and boiling point Is higher than the reaction product with other materials. Therefore, the reaction product is not easily melted and sublimated from the surface of the corrosion-resistant member even by the heat of the plasma, and therefore has excellent corrosion resistance. The oxide ceramics used in the present invention are preferably those having a purity of 99% or more and a relative density of 90% or more in terms of further improving the corrosion resistance. Furthermore, for the composite material of alumina and YAG, it is preferable to use a sintered body in which alumina is compounded in a proportion of 70 to 90 mass% and YAG in a ratio of 10 to 30 mass%. This is because if the proportion of YAG is less than 10% by mass, the corrosion resistance decreases, and if it exceeds 30% by mass, the strength decreases significantly.

  Next, the manufacturing method of the corrosion resistant member of the present invention will be described in detail below.

  As a method for producing an oxide ceramic sintered body used for the corrosion-resistant member of the present invention, for example, commercially available alumina having an average particle diameter of 0.5 to 10 μm and a purity of 96% or more is used as the ceramic material. Then, this ceramic material is granulated or slurried to obtain a secondary raw material. In the case of granulation, this ceramic material is mixed with various commercially available binders such as PVA (polyvinyl alcohol) and PEG (polyethylene glycol) and water as a solvent by a mixing stirrer, and then a ball mill or vibration mill. Further, the mixture is further mixed and stirred by a mixing mill such as a slurry having increased binder dispersibility. And this slurry is granulated with a spray dryer, and it is set as a secondary raw material. In addition, when making a slurry, this ceramic material is mixed with an acrylic resin binder, water, a curing agent, and a dispersant as a solvent in a mixing stirrer, and then defoamed by a deironer and defoamed by a vacuum defoamer. To obtain a slurryed secondary material.

  Thereafter, the granulated secondary material is molded using a molding method such as a die press molding method or an isostatic press molding method (rubber press), and the slurryed secondary material is subjected to a casting molding method or an injection molding method. Use to mold.

  Here, in the manufacturing method of the corrosion-resistant member of the present invention, the surface roughness of the surface of the molding die used at the time of molding is transferred to the surface of the molded body. In order to transfer the surface roughness of the surface of the mold to the surface of the molded body, the surface of the mold must first be processed to the desired surface roughness in the molded body. For processing the forming die, first, a metal ingot serving as a prototype of the die is prepared and processed into a predetermined shape using a metal processing apparatus such as a grinding machine or a milling machine. After that, a hard plating process is applied to the surface in contact with the secondary material, and a blasting process or a polishing process is applied to the plated surface to obtain the required arithmetic average height (Ra) and skewness (Rsk). Finish with a surface with kurtosis (Rku). In order to process the surface of the mold in various states, it is important to adjust the thickness of the plating when performing hard plating and the grain size and grain size used for polishing and blasting. It becomes.

  When it is desired to increase the arithmetic average height (Ra) of the surface of the oxide ceramic sintered body that is the corrosion-resistant member of the present invention, the thickness of the plating is increased, and the abrasive grains used for polishing and blasting are used. What is necessary is just to make a diameter coarse. In order to obtain the arithmetic average height (Ra) of 3 μm, which is the upper limit in the corrosion-resistant member of the present invention, at least the plating thickness is 5 μm, and the abrasive grains used in polishing and blasting are also 5 μm or less in size. Good. When it is desired to reduce the arithmetic average height (Ra) value of the surface of the sintered body, the plating thickness may be reduced to reduce the grain size of the abrasive grains used for polishing or blasting. In order to obtain an arithmetic average height (Ra) of 1 μm or less, it is preferable to set the plating thickness to 2 μm or less and the abrasive grain size to 2 μm or less.

  Furthermore, in order to keep the skewness (Rsk) of the surface of the sintered body within the range of the present invention, it is necessary to make the grain sizes of abrasive grains used for polishing and blasting as uniform as possible. When the grain size variation of the abrasive grains is large, it is difficult to obtain a surface state in which the probability density function of skewness (Rsk) has a normal distribution as in the present invention. For example, in the case of using abrasive grains having a particle size of 5 μm or less in order to obtain 3 μm as the arithmetic average height (Ra), 80% or more of them are in the range of 1 to 5 μm using a vibration sieve etc. It is better to adjust the particle size.

  Moreover, about the kurtosis (Rku) of the surface of a sintered compact, the particle shape of the abrasive grain used for a grinding | polishing process and a blast process influences. In order to make it within the preferred range of the present invention, commercially available alumina (WA), SiC, and diamond (GC) abrasive grains having a particle size of 2 to 100 μm are reground for several hours using a ball mill or vibration mill, The sharp corners of the grains should be as gentle as possible. The reason why re-pulverization is performed is that commercially available abrasive grains are pulverized in the shortest time to obtain the particle size, and the particle shape is not uniform. If the grain surface of the abrasive grains is such that the sharp corners are removed, when the abrasive grains come into contact with the plating surface of the mold, it is difficult to form high projections or deep depressions on the plating surface, and this plating surface is transferred. High protrusions and deep recesses are less likely to be present on the surface of the corrosion-resistant member of the present invention. In order to obtain a surface state with a kurtosis (Rku) of 3.0 to 4.5, abrasive grains that have been reground for 1 to 10 hours with a particle size of 2 to 100 μm may be used for polishing or blasting.

  In addition, the surface roughness of the mold surface transferred to the surface of the molded body must be determined in consideration of the shrinkage of the molded body in the subsequent firing process or the pressure to be molded. As a result, it has been found that there is little influence of the molding pressure, and only the shrinkage in the firing process should be taken into consideration. Therefore, for example, if it is intended to obtain a corrosion-resistant member having the surface state of the present invention using alumina as the oxide ceramic sintered body, the arithmetic average height (Ra) of the mold is taken into consideration in consideration of the shrinkage rate during firing. Is preferably polished to a surface state in which the skewness (Rsk) is in the range of -1.0 to +0.5. In the processing of the surface state, polishing and blasting are performed again so as to obtain the desired surface state while repeating the processing and the measurement of the surface state. Then, if a molded body is prepared using this mold and fired, the oxide ceramic sintered having an arithmetic average height (Ra) of 3 μm or less and a skewness (Rsk) of −1.0 to +0.5. A corrosion-resistant member made of a body can be obtained. Furthermore, it is preferable that kurtosis (Rku) is in the range of 3.0 to 4.5.

Here, the press molding method using a metal mold has been described as an example. However, when the contact surface with the molded body is other than metal, it is difficult to carry out the manufacturing method of the present invention. Therefore, in the hydrostatic press molding method, molding is generally carried out with rubber and metal molds, but the surface state of the molded body can be efficiently within the scope of the present invention. Is only a portion in contact with the surface of the metal mold. Further, in the casting molding method, a water-absorbing gypsum mold or a non-water-absorbing metal mold is used, but the surface state of the molded body can be efficiently within the scope of the present invention. Only the gel casting method using Thus, the molding method must be taken into account depending on the product shape and in which part the surface condition in the present invention is necessary.
Next, the obtained molded body is fired. A commercially available firing furnace may be used, and the firing atmosphere may be an air atmosphere or an oxidizing atmosphere. The firing temperature may be fired at the highest temperature at which the oxide ceramic sintered body used as the corrosion-resistant member is sufficiently densified. In the manufacturing method of the present invention, the temperature pattern on the temperature-lowering side after maintaining the maximum temperature is 5 to 20 ° C./hour from the maximum temperature to 1000 ° C., 20 to 50 ° C./hour from 1000 to 500 ° C., 500 The temperature is lowered from 50 ° C. to room temperature in a temperature pattern of 50 to 100 ° C./hour.

  Here, in the firing method of the corrosion-resistant member of the present invention, the temperature pattern of firing on the temperature lowering side is controlled by controlling the grain growth of the oxide ceramic particles on the surface of the corrosion-resistant member or in the vicinity thereof, and the surface state is good. This is for maintaining the state. Particles on or near the surface of the corrosion-resistant member undergo grain growth and firing shrinkage during the temperature rise process of firing, but the degree of grain growth varies with a slight temperature difference, and thus firing shrinkage also varies. . This variation is averaged by adjusting the temperature pattern on the temperature drop side, especially by setting the temperature pattern to slow down the temperature drop rate from the maximum temperature to 1000 ° C, giving thermal energy to small crystal grains and promoting grain growth. The entire surface to which the surface roughness of the mold is transferred is in a surface state within the scope of the present invention.

  More specifically, the maximum temperature to 1000 ° C is set to 5 to 20 ° C / hour. When the temperature is less than 5 ° C./hour, the rate of temperature decrease is too slow, and the surface of the corrosion-resistant member or the particles in the vicinity thereof further grow while maintaining the grain growth variation at the maximum firing temperature. The size of the particle crystal is not averaged, and the entire transfer surface of the mold cannot be brought into the surface state within the scope of the present invention. Furthermore, it is not preferable because the grains grow too much and the strength of the oxide ceramic sintered body is remarkably lowered. Further, if the temperature lowering rate exceeds 20 ° C./hour, it is not preferable because the temperature decreasing rate is too high and slow, as in the case where the temperature decreasing rate is too slow.

  Moreover, the temperature-fall rate from 1000 degreeC to 500 degreeC shall be 20-50 degreeC / hour. The temperature range must be controlled by reducing the temperature difference that occurs on the surface of the corrosion-resistant member rather than grain growth, and mitigating the effects of thermal stress due to heat shock, etc., and the surface state of the corrosion-resistant member of the present invention It is for maintaining. A temperature lowering rate of less than 20 ° C./hour is not preferable because the temperature lowering is too slow, so that a long time is required for firing, the production efficiency of the corrosion-resistant member is lowered, and the production cost is remarkably increased. On the other hand, when the temperature decreasing rate exceeds 50 ° C./hour, a temperature difference is likely to occur on the surface of the corrosion-resistant member, and a fine crack is generated on the surface due to the thermal stress generated by the temperature difference, and a surface state within the scope of the present invention is obtained. This is not preferable because there is a risk of not being present.

  Moreover, the temperature-fall rate from 500 degreeC to normal temperature (room temperature) shall be 50-100 degreeC / hour. If the rate of temperature drop is less than 50 ° C / hour, the temperature drop is too slow, so it takes a long time for firing, which is not preferable because the production efficiency of the corrosion-resistant member is lowered and the manufacturing cost is significantly increased. If the temperature lowering rate is higher than that, it is not preferable because fine cracks are generated due to the influence of thermal stress generated on the surface, and the surface state within the scope of the present invention cannot be maintained.

  And after completion | finish of baking, the corrosion-resistant member which consists of an oxide ceramic sintered compact of this invention is obtained by taking out a sintered compact from a kiln and wash | cleaning the surface lightly. The obtained corrosion-resistant member does not need to be particularly ground, but if it is somewhat deformed by firing, it is ground to a surface other than the surface that contacts corrosive gas when attached to a semiconductor manufacturing device. It is also possible to correct the deformation at a temperature of 1000 ° C. or lower while applying a load to the deformation site.

  The corrosion-resistant member of the present invention thus manufactured is a member for a semiconductor manufacturing apparatus, particularly in an apparatus for forming a CVD film such as a nitride film or an oxide film on a semiconductor wafer while performing an etching process by plasma CVD. Further, it can be used for a halogen-based corrosive gas or a site in contact with the plasma thereof.

  As mentioned above, although the example of embodiment of this invention was demonstrated, the corrosion-resistant member of this invention is not limited to the above-mentioned content, You may change variously, if it is in the range which does not deviate from the summary. Needless to say. For example, in the above example, the details of the corrosion-resistant member made of an oxide ceramic sintered body have been described in detail. However, if the surface exposed to the halogen-based corrosive gas is in the surface state within the scope of the present invention, various The same effect can be obtained with a corrosion-resistant member having an oxide ceramic film formed on the surface of the substrate.

  Details of the embodiments of the present invention will be described below.

(Example 1)
The conventional corrosion-resistant member and the corrosion-resistant member of the present invention are installed on the outer wall of the chamber of the RIE (reactive ion etching) apparatus, and a high-frequency output of 140 W is applied to the apparatus electrode in a mixed gas atmosphere of CF ₄ , CHF ₃ , and Ar. Was applied to generate plasma and etch the silicon wafer surface.

  First, 100 kg of a commercially available primary alumina material (purity 99.5%, average particle size 1 μm), 2 parts of commercial PVA (polyvinyl alcohol) as a binder for 2 parts by mass of 100 parts by mass of this alumina raw material, and water. 100 kg of 100 parts by mass of 100 parts by mass of the primary alumina raw material was weighed, put into a mixing stirrer and mixed for several hours, and then mixed for several hours by a ball mill to obtain a slurry for granulation. . Thereafter, this slurry was put into a spray dryer apparatus and granulated to obtain alumina granulated powder as a secondary raw material. Then, after filling the secondary material with a mold in which the inner surface filled with the secondary material is machined to an arithmetic average height (Ra) of 1 μm and a skewness (Rsk) of −0.05, the unit is formed by a die press molding machine. Molding was performed at a molding pressure at which the pressure per area was 100 MPa to obtain a molded body. Thereafter, the compact is held at a maximum temperature of 1600 ° C for 2 hours, from 1600 ° C to 1000 ° C at 10 ° C / hour, from 1000 ° C to 500 ° C at 30 ° C / hour, from 500 ° C to room temperature (room temperature). Was cooled at a rate of 80 ° C./hour to obtain a corrosion-resistant member comprising the oxide ceramic sintered body of the present invention.

  On the other hand, for a conventional corrosion resistant member, a secondary material is filled in a mold having an arithmetic average height (Ra) of less than 1 μm, and molded at a molding pressure at which the pressure per unit area is 100 MPa, and then 1600 ° C. After firing at the highest temperature and cooling down to room temperature at an average rate of 50 ° C./hour to obtain an alumina sintered body, this surface is processed with a blasting apparatus so that the arithmetic average height (Ra) is 10 μm. Thus, a conventional corrosion-resistant member was obtained.

  Next, the corrosion-resistant member of the present invention and the conventional corrosion-resistant member were ultrasonically cleaned in pure water for 1 hour, and then the arithmetic average height (Ra), using a commercially available non-contact type surface roughness meter, Skewness (Rsk) and kurtosis (Rku) were measured. The measurement conditions are such that the estimated arithmetic average height (Ra) is 0.1 μm in accordance with JIS standards (JIS B 0601-2001, JIS B 0633-2001, JIS B 0031-2003 appendices G and F). When the value is larger than 2 μm, the evaluation length is 4 mm, the cutoff value (reference length) is 0.8 mm, and when the estimated arithmetic average height (Ra) is larger than 2 μm and 10 μm or less, the evaluation length is The cut-off value (reference length) was set to 12.5 mm and 2.5 mm.

  Further, the average crystal grain size at the surface of each corrosion-resistant member or the depth from the surface to 100 μm was calculated from an SEM photograph of 1000 times.

  The average crystal grain size was measured by preparing a test piece cut out from a corrosion-resistant member, and further removing the grain boundary composition of the alumina crystal by chemically or heat treating the observation surface to remove the grain boundary composition of the alumina crystal. A photograph was taken with a scanning electron microscope (SEM) at a magnification of 10 and arbitrarily selected 10 crystal grains from the photographic image, and the maximum length of each crystal grain was defined as the crystal grain size. The average of the measured values was calculated as the average crystal grain size.

Furthermore, the test which confirms the change rate of an etching rate when using each corrosion-resistant member was done. Specifically, the corrosion-resistant member of the present invention or the conventional corrosion-resistant member was installed on the chamber wall surface of the RIE apparatus, and the silicon wafer was etched for 1 hour, 9 hours, and 10 hours under the same conditions. The weight of the corrosion-resistant member was measured with an electronic balance before the start of etching, after 1 hour of etching, after 9 hours of etching, and after 10 hours of etching. The etching rate from after to 10 hours after execution was calculated. The rate of change in the etching rate is (E1−E2) / E1 ×, where E1 is the etching rate from the start of etching to 1 hour after etching, and E2 is the etching rate from 9 hours to 10 hours. It was calculated by a calculation formula of 100 (%). The above measurement results are summarized in Table 1.

  As a result, the arithmetic average height (Ra) of the conventional corrosion-resistant member was 5.5 μm, the skewness (Rsk) was −2.5, and the kurtosis (Rku) was 6.5, whereas the corrosion-resistant member of the present invention had an arithmetic average height of The thickness (Ra) was 0.7 μm, the skewness (Rsk) was −0.1, and the kurtosis (Rku) was 3.8. As for the average crystal grain size, the corrosion resistant member of the present invention was 25 μm and the conventional corrosion resistant member was 23 μm, but there was no great difference in value, but the conventional corrosion resistant member had a large variation in value.

  The rate of change in the etching rate of the conventional corrosion-resistant member was 80% due to the large values of arithmetic average height (Ra), skewness (Rsk), and kurtosis (Rku), and the etching rate was not stable. As described above, in the conventional corrosion-resistant member having an uneven portion on the surface having a large skewness (Rsk) or kurtosis (Rku) value, the plasma generated in the apparatus is not stable, and it is difficult to stabilize the etching rate. The result was confirmed.

  On the other hand, the rate of change of the etching rate by the corrosion-resistant member of the present invention is 10%, and the etching rate hardly changes from the initial stage of generating plasma by applying a high frequency, by using the corrosion-resistant member of the present invention, It was confirmed that the plasma in the apparatus can be stabilized and the etching rate can be stabilized from the initial stage.

(Example 2)
Next, the corrosion-resistant member of the present invention was molded with a molding die in which the arithmetic average height (Ra) of the inner surface was variously changed using the same alumina secondary material as in Example 1, and this molded body was subjected to firing. It was fired and manufactured by changing the cooling rate from the maximum temperature to 1000 ° C. In accordance with JIS B 0601-2001, the arithmetic average height (Ra), skewness (Rsk), kurtosis (the surface of the corrosion-resistant member was measured with a commercially available non-contact surface roughness meter under the same conditions as in Example 1. After measuring Rku), it was installed on the inner wall of the chamber of the same RIE apparatus as in Example 1, and a test for measuring the change rate of the etching rate under the same conditions was performed.

  Further, from each sintered body after firing, the sintered body is processed in advance in accordance with JIS R 1601-1995, and the arithmetic average height (Ra) is 0.2 μm or less, the length is 36 mm, and the width is 4 mm. , A test piece having a thickness of 3 mm and a 0.2 mm C-face was prepared, and a load tester was used to apply a load to the test piece to measure the maximum load until breakage. The point bending strength was calculated.

3-point bending strength σ ₃ (N / mm ² ) = 3PL / 2 wt ²
Here, P is the maximum load (N) when the test piece breaks, L is the distance between the lower fulcrums (mm), w is the width (mm) of the test piece, and t is the thickness (mm) of the test piece. .

The above test results are summarized in Table 2.

  From the results shown in Table 2, sample No. For 1 to 3, the arithmetic average height (Ra) of the surface of the mold was larger than 4 μm, and the arithmetic average height (Ra) of the surface of the corrosion-resistant member after firing exceeded 3 μm, so it was generated in the RIE apparatus. It was confirmed that the plasma generated was unstable, the rate of change of the etching rate after 1 hour and 10 hours was as large as 30% or more, and the etching rate was not stable.

  In particular, sample No. For 1, the values of skewness (Rsk) and kurtosis (Rku) were also increased to +0.8 and 5.6, respectively, indicating that the rate of change of the etching rate was large and unstable.

  In addition, sample No. outside the scope of the present invention. For 4, 8, 11, and 14, the temperature drop rate from 1600 ° C to 1000 ° C, the maximum temperature during firing, was too slow, and the crystal grain size at or near the surface of the sintered body was too large, resulting in corrosion resistance. The strength of the member was as low as less than 300 MPa. Further, the skewness (Rsk) and kurtosis (Rku) values were large, and the rate of change of the etching rate was as high as 30% or more.

  Furthermore, sample nos. For No. 7, the temperature drop rate from the maximum temperature of 1600 ° C. to 1000 ° C. during firing was too high, so that fine cracks were generated on the surface of the sintered body, and the strength of the corrosion-resistant member was as low as less than 300 MPa.

  Compared with these samples, the sample No. within the scope of the present invention. For 5, 6, 9, 10, 12, 13, 15, and 16, the change rate of the etching rate is small, and the three-point bending strength of the corrosion-resistant member is 300 MPa or more, which is suitable as a member for a semiconductor manufacturing apparatus such as a plasma CVD apparatus. It was confirmed that it can be used for.

It is explanatory drawing of the property of skewness (Rsk), (a) is a roughness curve and probability density function in case skewness (Rsk) takes a positive value, (b) is a skewness (Rsk) takes a negative value. (C) is a roughness curve and a probability density function when the skewness (Rsk) value approaches zero. It is explanatory drawing of the property of kurtosis (Rku), (a) is a roughness curve and probability density function when kurtosis (Rku) is larger than 3, (b) is when kurtosis (Rku) is smaller than 3. Roughness curve and probability density function.

Claims (4)

A corrosion-resistant member comprising an oxide ceramic sintered body and having an arithmetic average height (Ra) of a surface exposed to a halogen-based corrosive gas or plasma thereof of 3 μm or less, the average crystal of the oxide ceramic sintered body A corrosion-resistant member having a particle size of 1 to 50 µm and a skewness (Rsk) determined from the surface roughness curve in the range of -1.0 to +0.5. 2. The corrosion-resistant member according to claim 1, wherein a kurtosis (Rku) determined from a roughness curve of the surface of the oxide ceramic sintered body is 3.0 to 4.5. The corrosion-resistant member according to claim 1, wherein the oxide ceramic sintered body is made of alumina, yttria, or a composite material of alumina and yttrium, aluminum, and garnet. It is a manufacturing method of the corrosion-resistant member in any one of Claims 1-3, Comprising: The process which mixes a ceramic material, a binder, and a solvent, and obtains a secondary raw material, The said secondary raw material is filled in a shaping | molding die. Forming a molded body in which the arithmetic average height of the surface of the mold is transferred to the surface, and holding the maximum temperature of 1550 to 1700 ° C. for 2 hours or more in the air or in an oxidizing atmosphere; From 1000 ° C. to 1000 ° C. at 5 to 20 ° C./hour, from 1000 ° C. to 500 ° C. at 20 to 50 ° C./hour, and from 500 ° C. to room temperature at a rate of 50 to 100 ° C./hour. A method for producing a corrosion-resistant member.

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