JP2005281054A - Aluminum oxide-based sintered compact, its producing method, and member for semiconductor or liquid crystal producing equipment, which is obtained by using the sintered compact - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that it is impossible to produce a good product because the deformation amount becomes large when the amount of a sintering aid is increased so as to lower the sintering temperature and to reduce the production cost of a product having a large size and a thick part, in the production of an aluminum oxide sintered compact used as a member for a semiconductor or liquid crystal producing equipment. <P>SOLUTION: The aluminum oxide sintered compact contains, as a main component, ≥95 mass % aluminum oxide and ≤5 mass % sintering aid, and has a thick part wherein at least a part has a thickness of ≥5 mm. In the aluminum oxide sintered compact, the average crystal grain diameter in the vicinity of the surface of the sintered compact is larger than that in the inside, and the difference between the average crystal grain diameters in the vicinity of the surface and in the inside is ≤10 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aluminum oxide sintered body and a manufacturing method thereof, and further, an inner wall material (chamber), a microwave introduction window, a shower head, a focus ring, and a shield of a semiconductor manufacturing apparatus using the aluminum oxide sintered body. Applicable to members such as rings, liquid crystal manufacturing equipment stages, mirrors, mask holders, mask stages, chucks, reticles, and other semiconductors, and liquid crystal manufacturing equipment (etchers and CVDs) with large and thick parts It can be done.

  In recent years, aluminum oxide sintered bodies have been widely used in various technical fields because of their excellent thermal, mechanical and chemical properties.

  One of the applications using the high corrosion resistance of the aluminum oxide sintered body is a member for a semiconductor or liquid crystal manufacturing apparatus. This member for semiconductor and liquid crystal manufacturing equipment is high because it comes into contact with halogen-based corrosive gases such as fluorine and chlorine that are highly reactive and used for etching and cleaning in semiconductor and liquid crystal manufacturing processes and their plasmas. There is a demand not only for corrosion resistance but also for low dielectric loss, and the ceramic that satisfies this demand and can be compromised in terms of cost is an aluminum oxide sintered body.

  While the need for such an aluminum oxide sintered body is increasing, various studies have been conducted on how to manufacture it at a low cost.

  Here, various methods are conceivable as methods for reducing the production cost of the aluminum oxide sintered body, and among them, the characteristics of the aluminum oxide sintered body are not deteriorated, and the sintering is performed at a lower temperature than before. Studies of manufacturing methods to tie are actively conducted.

For example, high purity aluminum oxide sintered body of 99% by mass or more contains SiO ₂ , CaO, MgO as sintering aids, and the content is controlled within a certain range, so that sintering is performed at a low temperature. However, an example of an alumina porcelain composition with improved high-frequency dielectric loss characteristics is shown (see Patent Document 1).

In addition, a small amount of Na ₂ O or K ₂ O is added to the above-mentioned aluminum oxide sintered body in which the ratio of SiO ₂ , CaO, and MgO content is controlled, so that sinterability is further enhanced and high-speed firing is possible. An example of the prepared alumina porcelain composition is shown (see Patent Document 2).
JP-A-6-16469 Japanese Patent No. 3026011

  However, in both Patent Documents 1 and 2, since the average crystal particle diameter in the vicinity of the surface is larger than the inside, there is no problem with a small size, but when a large sintered body is formed, the surface has a remarkable shrinkage difference during firing. There was a problem that deformation such as warpage and undulation occurred. In particular, this phenomenon is considered to be further increased as the size is increased. The reason for this difference in shrinkage is that sintering aids other than aluminum oxide, which have a low melting point, gather near the surface of the sintered body as a liquid phase during firing. Grain growth is promoted and grain growth is not promoted, but not only the grain growth is not promoted inside and the inside and the inside of the surface cannot be made uniform. It is considered that the sintered body is deformed.

  As a countermeasure against this deformation, it is conceivable to adjust the deformation of the sintered body by grinding after firing. In other words, a lot of grinding allowance, which is a grinding area, is formed to correct the deformation by grinding. However, in this case, the raw material cost and processing cost of the portion removed as the grinding allowance are wasted, and the manufacturing cost is increased. There is a problem that it ends up.

  On the other hand, in Patent Document 1, since it is a high-purity sintered body of 99% by mass or more, even if the content of Si, Ca, and Mg is controlled, it is difficult to lower the firing temperature and it is difficult to reduce the production cost. There was also a problem that there was.

  In contrast, an aluminum oxide sintered body to which a large amount of a sintering aid component has been added for lowering the temperature is a component other than aluminum oxide having good corrosion resistance when used as a semiconductor or liquid crystal manufacturing apparatus member. There is a problem that the corrosion resistance against fluorine, chlorine and bromine halogen corrosive gases and their plasma is reduced.

  In view of the above-mentioned problems, the present invention provides a sintered body having 95% by mass or more of aluminum oxide as a main component and 5% by mass or less of a sintering aid composed of at least a metal element of Si, Ca and Mg and having a thick part of 5 mm or more. The sintered body is characterized in that an average crystal particle diameter in the vicinity of the surface of the sintered body is larger than the inside, and a difference thereof is 10 μm or less.

It is preferable that CaO / SiO _{2 of the} metal element is 0.3 to 3 and MgO / SiO ₂ is 1 to 5.

The metal element may contain Si in terms of mass of 6000 ppm or less in terms of SiO ₂ , Ca in terms of CaO in terms of 6000 ppm or less, and Mg in terms of MgO of 12000 ppm or less.

  On the other hand, as the method for producing the aluminum oxide sintered body of the present invention, 50 to 90% by mass, 0.5 to 0.7 μm of powder having an aluminum oxide primary material particle size distribution D50 of 0.8 to 1.5 μm is used. A step of mixing 10 to 50% by mass of the above powder, a step of filling and molding the raw material powder in a mold, a load value of 10 to 50% of the breaking load, and a temperature of 1600 ° C. or less for 5 hours or more Prepare a firing jig having a characteristic that the creep deformation amount of the JIS R1601-1995 bending test specimen size under a heated condition is 5 mm or less, and the firing jig is brought into contact with the molded body and fired at 1500 to 1600 ° C. And obtaining a sintered body.

    It is preferable that Na contained in the alumina primary raw material powder is 40 ppm or less.

  The firing jig preferably has a JIS load softening point of 1800 ° C. or higher.

    Further, the aluminum oxide sintered body is used as a member for a semiconductor or liquid crystal manufacturing apparatus.

  According to the present invention, a sintered body having an average crystal particle diameter near the surface larger than the inside and a difference of 10 μm or less can suppress the shrinkage difference between the surface near and the inside. Even if the size of the sintered body is increased, the internal stress applied to the vicinity and the inside of the sintered body can be suppressed, and the deformation of the outer peripheral surface can be effectively prevented.

  Therefore, since there is no deformation, the grinding process can be omitted, and the manufacturing cost can be reduced even if such a sintered body is enlarged.

  In addition, since the sintering aid is moderately contained while suppressing the above-mentioned deformation, not only can firing at a lower temperature than conventional, but also corrosive gases and chemicals used in semiconductor and liquid crystal manufacturing processes. On the other hand, high corrosion resistance can be maintained.

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

  The aluminum oxide sintered body of the present invention contains 95% by mass or more of aluminum oxide as a main component and 5% by mass or less of a sintering aid composed of a metal element of Si, Ca, Mg, at least a part of which is 5 mm or more. It is a sintered body having a thick part, and the average crystal particle diameter in the vicinity of the surface of the sintered body is larger than the inside and the difference is 10 μm or less.

The reason why aluminum oxide is 95% by mass or more is that when the content is less than that, when used as a member for a semiconductor / liquid crystal manufacturing apparatus, SF ₆ , CF ₄ , CHF ₃ , ClF ₃ , NF ₃ , Halogenous corrosive gas such as fluorine-based gases such as C ₄ F ₈ and HF, chlorine-based gases such as Cl ₂ , HCl, BCl ₃ and CCl ₄ , or bromine-based gases such as Br ₂ , HBr and BBr ₃ and plasma thereof. This is because the content of aluminum oxide having good corrosion resistance is small and the corrosion resistance is lowered. In addition, the amount of the sintering aid composed of the metal elements of Si, Ca, and Mg contained in the aluminum oxide sintered body is set to 5% by mass or less because more than 5% by mass of the sintering aid is included. This is because, since the melting point of the reaction product of the sintering aid component and the halogen-based corrosive gas is low, the corrosion resistance of the entire member is lowered. More preferably, if the lower limit is 0.5 mass%, the temperature can be lowered as compared with the prior art.

  Here, the aluminum oxide sintered body is preferably a sintered body having a thick portion of at least 5 mm, more preferably 10 mm or more. In this case, the average crystal particle diameter in the vicinity of the sintered body surface is larger than the inside and the difference is set to 10 μm or less for the following reason. That is, the amount of sintering aid composed of metal elements of Si, Ca, Mg is used to lower the firing temperature in order to reduce the manufacturing cost of large-sized, thick-walled products having at least a part of 5 mm or more. If a large amount is added or increased, the temperature can be lowered, but among the increased sintering aids, Si and Al and Si compounds having a low melting point gather in the vicinity of the surface during the firing process due to the low melting point. This promotes crystal grain growth in the vicinity of the surface, which appears as a difference in crystal grain size with a difference in shrinkage between the surface and the inside of the same sintered body, and finally increases the amount of deformation. . For this reason, even if the size of the sintered body is increased, the internal stress applied to the vicinity and the inside of the surface of the sintered body can be suppressed, thereby preventing the outer peripheral surface from being deformed. This phenomenon appears more prominently when the thickness is 10 mm or more. In addition, the surface vicinity of a sintered compact means the range of the thickness from the sintered compact surface to at least 25% of a thick part, and let other part be an inside.

  Regarding the difference in the average crystal grain size, the cross section of the sintered body within the range from the surface to the thickness of 15% of the thick part and the other part, in particular, the center part of the sintered body is mirror-finished and etched. This can be confirmed by observing with a scanning electron microscope or the like. Further, a crystal photograph can be taken with a scanning electron microscope at a predetermined magnification, and an average of crystal grain diameters within a certain range of the photograph can be calculated and confirmed by comparison.

Thus, in order to control the difference within the range of 10 μm, the average crystal grain size in the vicinity of the surface is larger than the inside, in order to enhance the sinterability of the sintered body, Si, Ca, Mg added It is necessary to control the ratio of the amount of metal element. Si, Ca, and Mg have a high melting point in the sintering process of aluminum oxide, respectively. Mg and Ca have a high melting point, and have a crystal growth inhibiting action to form a compound with Al at the crystal grain boundary. On the contrary, Si has a melting point. Is low and promotes crystal growth. Mg has a higher crystal growth suppression effect than Mg and Ca. When the ratios of Mg, Ca and Si are converted into oxides, respectively, it is important to set the mass ratio CaO / SiO ₂ = 0.3 to 3 and the mass ratio MgO / SiO ₂ = 1 to 5 in the range. is there. In addition, even if it is a large sized and thick product which has a thick part of 5 mm or more by making this ratio into such a range, the balance of crystal growth and suppression is good, and the average crystal near the surface and inside Difficult to make difference in particle size.

If the mass ratio CaO / SiO ₂ mass ratio is lower than 0.3, crystal growth is promoted and a difference in the crystal grain size is likely to occur between the vicinity and inside of the sintered body, and the SiO ₂ component is a crystal of aluminum oxide. It is not preferable because it exists as a liquid layer between the particles and lowers the mechanical properties of the sintered body. Further, if the mass ratio MgO / SiO ₂ is lower than 1, it is not preferable because crystal growth is promoted similarly. On the other hand, if the mass ratio CaO / SiO ₂ is greater than 3, the effect of suppressing crystal growth is too great and the sintered body does not become dense at low temperatures. Similarly, when the mass ratio MgO / SiO ₂ is greater than 5, the crystal growth inhibiting effect is too great, and the sintered body does not become dense.

Moreover, as content in the sintered compact of Si, Ca, and Mg, Si is 6000 ppm or less in terms of SiO ₂ , Ca is 6000 ppm or less in terms of CaO, and Mg is 12000 ppm or less in terms of MgO on a mass basis. preferable. Here, the Si content of 6000 ppm or less in terms of SiO ₂ is not preferable because the Si content is more than 6000 ppm because the crystal growth effect is promoted and the amount of deformation increases due to the above-described action in large and thick products. Further, the corrosion resistance to halogen-based corrosive gases used in semiconductor and liquid crystal manufacturing processes, plasmas thereof, and other corrosive chemicals is not preferable. Further, if Ca is more than 6000 ppm in terms of CaO, it is not preferable because densification at a low temperature becomes difficult and corrosion resistance to corrosive gases and chemicals is reduced as in the case of Si. Further, if Mg is more than 12000 ppm in terms of MgO, it is not preferable because densification at a low temperature becomes difficult like Ca.

  In addition, the measurement of the metal element amount of Si, Ca, and Mg can be measured with an ICP emission spectroscopic analyzer.

Furthermore, the aluminum oxide sintered body of the present invention preferably has a density of 3.8 g / cm ³ or more. This is because, at a density lower than 3.8 g / cm ^3, not only mechanical properties such as strength decrease, but also corrosion resistance against corrosive gases and chemicals decreases.

  Next, the manufacturing method of the aluminum oxide sintered body of this invention is demonstrated.

The raw material of the aluminum oxide sintered body of the present invention can be obtained, for example, by adding a predetermined amount of SiO ₂ , CaO, MgO refined raw material to aluminum oxide powder having a purity of 95% or more. At this time, as the particle size of the primary material, D50 in the particle size distribution obtained by the laser diffraction method is 0.8 to 1.5 μm, 50 to 90 mass%, and D50 is 0.5 to 0.7 μm, 10 to 50. Mix at a mass percentage. By blending in this way, the primary raw material particles having a small D50 enter the gaps between the primary raw material particles having a large D50, so that the green density of the molded body after molding can be improved. In addition to improving handling properties, the density of the sintered body is also improved.

  Here, in the region where D50 is 0.8 to 1.5 μm and the particle size is large, particles having a small particle size for entering the gap between the particles and improving the raw density are obtained when the particle size is smaller than 0.8 μm. This is because it is difficult to manufacture at a low cost, and when the particle diameter is larger than 1.5 μm, it is difficult to make the sintered body dense. In addition, in the region where D50 is as small as 0.5 to 0.7 μm, the particle size is too small at 0.5 μm or less so that the green density of the molded body is improved. This is because the effect is poor, and when the particle diameter is larger than 0.7 μm, it is difficult to enter the gap between large particles, and it is difficult to improve the green density.

  Also, the amount of impurities contained in the primary raw material powder of aluminum oxide should be 0.1% or less. In particular, when the Na component is made into a sintered body and then used in a semiconductor manufacturing process or the like, Since it becomes a contamination source, it is better to reduce it as much as possible within the range of 40 ppm or less.

  In addition, as a sintering aid powder composed of metal elements of Si, Ca, Mg, natural raw materials such as dolomite, kaolin, talc, clay, feldspar, lime, etc. composed of Si, Ca, Mg components are not expensive refined raw materials. In this case, it is preferable to use a material having as little impurity as possible in order to avoid deterioration of the characteristics of the aluminum oxide sintered body.

  Next, the aluminum oxide primary raw material powder and the sintering aid powder are mixed with a solvent, a binder, a dispersant and the like by a mixing mill to form a slurry. Thereafter, the slurry is granulated by a spray granulator such as a spray dryer to obtain a secondary raw material powder that can be easily molded. Then, the secondary raw material powder is filled into a mold and molded. As a molding method, any molding method can be used as long as it is a molding method in which primary and secondary raw material powders are filled into a mold, such as a press molding method, a cold isostatic press molding method, a casting molding method, and an injection molding method. Although it is possible, in manufacturing a product having a large thick part, it is more preferable to use a casting method or a cold isostatic pressing method.

  And after obtaining a molded object as mentioned above, baking is performed. Any firing furnace can be applied as long as it can raise the temperature to around 1800 ° C., and a large furnace having a large firing capacity is used for manufacturing a product having a large thick part. The aluminum oxide sintered body of the present invention can be obtained by firing the compact at a temperature of 1500 to 1600 ° C. in a firing furnace.

  At this time, the firing jig used in the firing furnace has a load value of 10 to 50% of the breaking load, and the size of the JIS R1601-1995 bending test piece under the condition of heating at a temperature of 1600 ° C. or less for 5 hours or more. A material having a creep deformation amount of 5 mm or less is used, and this is abutted against a molded body and fired. Such a jig is often used to prevent deformation due to its own weight when a molded product having a large thick part is fired. Here, since the aluminum oxide sintered body having a thick portion at least partially 5 mm or more as in the present invention has a large shape, a firing jig is used to prevent deformation due to its own weight during firing. The deformation of each part will be suppressed. Therefore, if the firing jig is deformed, the amount of deformation is directly reflected in the aluminum oxide sintered body. Therefore, since it is necessary to suppress the deformation amount of the jig, a firing jig that meets the above conditions is specified. When the creep deformation amount is set to 5 mm or less, if it is more than 5 mm, the jig is deformed by the load of the sintered body when actually used during firing, which is not preferable.

  Further, as the material of the firing jig, it is preferable to use a material having a characteristic that the JIS load softening point is 1800 ° C. or higher because the weight acts as a load at a high temperature when supporting the weight of the sintered body. According to the examination so far, a firing jig made of a material having a JIS load softening point lower than 1800 ° C. undergoes significant deformation during firing, and this deformation is transferred to the aluminum oxide sintered body. It is not preferable. Specific materials include high-purity alumina, mullite, SiC, magnesia, zirconia, and the like.

  The aluminum oxide sintered body of the present invention obtained through the manufacturing method as described above has an average crystal grain size in the vicinity of the surface at a thick part of 5 mm or more larger than the inside, and the difference can be 10 μm or less. It is possible to manufacture a good sintered body without causing a difference in characteristics between the surface and the inner sintered body and causing deformation of the sintered body.

  Next, an example in which the aluminum oxide sintered body of the present invention is used as a processing container member of an inductively coupled plasma etching apparatus which is a semiconductor manufacturing apparatus is shown in FIG.

FIG. 1 is a schematic cross-sectional view showing an inductively coupled plasma etching apparatus, and reference numeral 1 in the figure is a processing container 1 of the present invention. The processing vessel 1 has a dome shape and has a rough surface portion 2 on the inner wall surface, and a metal lower chamber 3 is provided below the processing vessel 1 so as to form the chamber 3. Has been. A support table 4 is disposed in the upper part of the lower chamber 3, and an electrostatic chuck 5 is provided thereon, and a semiconductor wafer 6 is placed on the electrostatic chuck 5. A direct current power source is connected to the electrode of the electrostatic chuck 5, thereby electrostatically adsorbing the semiconductor wafer 6. The support table 4 is connected to an RF power source. On the other hand, a vacuum pump 9 is connected to the bottom of the lower chamber 3 so that the inside of the chamber 3 can be evacuated. A gas supply nozzle 7 for supplying an etching gas such as CF ₄ gas is provided above the semiconductor wafer 6 above the lower chamber 3. An induction coil 8 is provided around the processing container 1, and a high frequency of 400 kHz, for example, is applied to the induction coil 8 from an RF power source.

In such an etching apparatus 10, the inside of the chamber 3 is evacuated to a predetermined degree of vacuum by the vacuum pump 9, the semiconductor wafer 6 is electrostatically adsorbed by the electrostatic chuck 5, and then, for example, CF ₄ gas is used as an etching gas from the nozzle 7. By supplying power to the induction coil 9 from the RF power supply, etching gas plasma is formed in the upper portion of the semiconductor wafer 6 and the semiconductor wafer 6 is etched into a predetermined pattern. Note that the anisotropy of etching can be increased by supplying power to the support table 5 from a high-frequency power source.

  During such an etching process, the inner surface of the processing container 1 is corroded by CF4 gas or plasma thereof, and a fluoride film or the like is attached thereto. However, since the processing container 1 is composed of the above-described aluminum oxide sintered body of the present invention, the corrosion resistance against plasma is high, and deposits are difficult to fall due to the influence of the rough surface portion 2 formed on the surface.

  The aluminum oxide sintered body of the present invention is not limited to the processing container of the semiconductor manufacturing apparatus as shown in FIG. 5, but is a member such as a chamber, a microwave introduction window, a shower head, a focus ring, a shield ring, or a liquid crystal manufacturing apparatus. Then, it is applicable as a large-sized member having a thick part, such as a stage, a mirror, a mask holder, a mask stage, a chuck, and a reticle.

  As mentioned above, although embodiment of this invention was described, it cannot be overemphasized that it can apply also to what was variously improved and changed if it is a range which does not deviate from the scope of the present invention.

  Examples of the present invention will be described below.

First, an aluminum oxide primary raw material powder having a purity of 95%, a particle size of 1.2 μm and a particle size of 80% by mass and 0.6 μm of 20% by mass is prepared. Next, purified SiO ₂ , CaO, and MgO powders were added at the ratio of CaO / SiO ₂ and MgO / SiO ₂ shown in Table 1, and sample No. Prepare the mixed powder which becomes the basis of 1-12.

  Next, 2% by mass of PVA and 100% by mass of water as a solvent are added to the mixed powder, put into a mixing mill and operated for 1 hour, and then the slurry is taken out. Then, the slurry is granulated into a secondary raw material powder with a spray dryer, which is then molded with a cold isostatic press molding device to obtain a molded body having a diameter of 75 mm × thickness of 12.5 mm. By firing at 1550 ° C., sample No. of an aluminum oxide sintered body having an outer diameter of φ60 mm × thickness of 5 mm was obtained. 1-12 were obtained.

  And sample no. About 1-12, the sample center part was cut | disconnected in thickness direction, the cross section was grind | polished and etched, and the crystal grain size of the position of 100 micrometers from the surface and the magnitude | size of the crystal grain diameter of a center part are 200 micrometers x 200 micrometers, respectively. In this range, measurements were taken based on a photograph taken at a magnification of 2000 times with a scanning electron microscope and averaged, and the average crystal grain size was calculated.

  Further, the corrosion resistance of each sample was set in an RIE (Reactive Ion Etching) apparatus, exposed to plasma in a fluorine-based gas atmosphere such as CF4, and the etching rate per minute was calculated from the weight loss before and after that. Each sample used in the corrosion resistance test has a mirror-finished surface.

The results are shown in Table 1.

From Table 1, sample No. For Nos. 1 and 7, the CaO / SiO ₂ ratio and MgO / SiO ₂ ratio added as sintering aids were not in the proper ranges, and the warped sintered body was significantly larger at 10 mm than other samples. It was.

Sample No. 6 and 12, the CaO / SiO ₂ ratio and the MgO / SiO ₂ ratio are not within the proper ranges, and are not sufficiently densified due to the large amounts of Ca and Mg that function to suppress crystal grain growth. It has not yet been evaluated.

  Compared to these, sample No. Nos. 2 to 6 and 8 to 11 were good because the difference from the inside of the crystal particle diameter in the vicinity of the surface was 10 μm or less, sufficiently densified without significant deformation.

  Next, sample No. 1 of Example 1 outside the scope of the present invention. 7 and sample No. within the range. 10 using a raw material specification similar to 10 and having a box-shaped rectangular parallelepiped having a width of 500 mm, a height of 500 mm, a depth of 700 mm, and a thickness of 20 mm as shown in FIG. 20 were manufactured.

  As a manufacturing method of the product, the steps from granulation to secondary raw material are the same as in Example 1, and then a box-shaped cuboid with one end opened by cold isostatic pressing. Was molded so that the sintered body after firing would have the above dimensions and finished by cutting to produce a molded body.

  Then, the compact is fired in an atmospheric furnace to obtain a sintered product 20. At this time, the open surface 21 of the product 20 is fired for shape retention so as not to be crushed by its own weight due to softening during firing. The jig 22 was set at a position as shown in the drawing in the direction perpendicular to the open surface 21. The firing jig 22 is made of high-purity alumina, and JIS R1601-1995 bending test under the condition of heating at 1600 ° C. for 5 hours or more when 10 to 50% of the breaking load is applied. One jig having a creep deformation amount of 5 mm or less and a JIS load softening point of 1800 ° C. or more is used as a jig material.

  Firing was performed at 1580 ° C. with such firing specifications to produce a product 20.

  As a result, sample no. The product 20 produced using the raw material No. 7 was greatly deformed, and the shape of the open surface 21 was distorted even though the firing jig was specified, so that it could not be used as a product.

  Compared to this, sample No. within the scope of the present invention. The product 20 produced as a raw material specification similar to that of FIG. 10 was able to maintain the shape of the figure and could be manufactured satisfactorily.

It is a schematic sectional drawing which shows the inductively coupled plasma etching apparatus using the aluminum oxide sintered body of this invention as a processing container. It is the schematic which shows the box-shaped rectangular parallelepiped by which one end of Example 2 of this invention was open | released.

Explanation of symbols

1: Processing container
2: rough surface portion 3: chamber 4: support table 5: electrostatic chuck 6: semiconductor wafer 7: gas supply nozzle 8: induction coil 9: vacuum pump 10: etching apparatus 20: product 21: open surface 22: firing jig

Claims (7)

A sintered body comprising 95% by mass or more of aluminum oxide, 5% by mass or less of a sintering aid composed of at least Si, Ca, and Mg metal elements, and having a thick portion of 5 mm or more, An aluminum oxide sintered body characterized in that the average crystal particle diameter in the vicinity of the surface is larger than the inside, and the difference is 10 μm or less. _2. The aluminum oxide sintered body according to claim 1, wherein a mass ratio of CaO / SiO ₂ in the metal element is 0.3 to _{3 and} a mass ratio of MgO / SiO ₂ is 1 to 5. 3. 3. The aluminum oxide sintered product according to claim 1, wherein the metal element contains Si in terms of mass of 6000 ppm or less in terms of SiO ₂ , Ca in terms of CaO in terms of 6000 ppm or less, and Mg in terms of MgO of 12000 ppm or less. body. Raw material powder obtained by mixing 50 to 90% by mass of powder having a primary material particle size distribution D50 of 0.8 to 1.5 μm and 50 to 90% by mass of D50 of 0.5 to 0.7 μm. Obtaining
A step of mixing the raw material powder with a binder, filling a mold and molding to obtain a molded body;
A firing jig having a characteristic that the creep deformation amount of the JIS R1601-1995 bending test specimen size is 5 mm or less under the condition that 10-50% of the breaking load is a load value and heated at a temperature of 1600 ° C. or less for 5 hours or more is prepared. And a step of bringing the firing jig into contact with the molded body and firing at 1500 to 1600 ° C. to obtain a sintered body. 5. The method for producing an aluminum oxide sintered body according to claim 4, wherein the amount of Na contained in the primary raw material powder of aluminum oxide is 40 ppm or less. The method for producing an aluminum oxide sintered body according to claim 4, wherein the firing jig has a JIS load softening point of 1800 ° C. or higher. A member for a semiconductor or liquid crystal manufacturing apparatus using the aluminum oxide sintered body according to any one of claims 1 to 3.

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