Yttrium oxide sintered body, its manufacturing method, and semiconductor manufacturing equipment component

Abstract

To provide an yttrium oxide sintered body that can be calcined at a low temperature and is excellent in plasma resistance, a method of producing the same, and a member for a semiconductor production device.SOLUTION: A yttrium oxide sintered body whose primary component is yttrium oxide, includes not less than 0.1 mass% and not more than 0.5 mass% of aluminum in terms of oxide, with the content of metal other than yttrium and aluminum being not more than 1000 ppm and its relative density being not lower than 98%, so that its plasma resistance can be made equal to or better than that of a high purity (purity of not lower than 99.9%) yttrium oxide sintered body. The yttrium oxide sintered body has a sufficiently high relative density, resulting in higher plasma resistance and excellent strength as a sintered body, so that it can be also suitable as a large sized member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an yttrium oxide sintered body, a method for producing the same, and a member for semiconductor manufacturing equipment. [Background technology]

[0002] Conventionally, yttrium oxide (Y2O3) sintered bodies with excellent plasma resistance have been used as semiconductor manufacturing equipment components, particularly as components used in plasma environments. High-purity yttrium oxide sintered bodies are used as semiconductor manufacturing equipment components because they need to prevent contamination of the workpiece with impurities (particles, etc.).

[0003] Patent Document 1 discloses an yttria ceramic part that has a high purity of 99.9 wt% or more and contains trace amounts of metal components of 100 ppm or less Si and 20 ppm or less Ca, by mass, and that addresses this problem: if yttria ceramics contains trace amounts of metal components, the trace amounts of metal components are likely to segregate at the grain boundaries of yttria crystals; and if an yttria ceramic part containing such trace amounts of metal components is exposed to a plasma atmosphere, the metal components corrode more easily than the yttria crystals in the plasma atmosphere, and so corrosion begins from the grain boundaries; when the grain boundaries of yttria crystals near the surface corrode, the yttria crystals fall off and adhere to the silicon wafer as dust.

[0004] Patent Document 2 discloses a corrosion-resistant ceramic member containing yttrium oxide as a main component and at least one of Zr, Si, Ce, and Al in an amount of 3 ppm by mass or more and 2000 ppm by mass or less, as a sintering aid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4798693 [Patent Document 2] Patent No. 4548887 Summary of the Invention [Problem to be solved by the invention]

[0006] Yttrium oxide is a material that is difficult to sinter, and high-temperature sintering is required to turn high-purity yttrium oxide into a dense sintered body.

[0007] In Patent Document 1, the calcined body of the yttria ceramic is sintered at a high temperature of 1700°C to 1850°C in a hydrogen gas atmosphere. However, sintering at a high temperature accelerates grain growth, resulting in a member composed of large grains, which are more likely to fall off. Then, corrosion progresses from the part where the grains have fallen off, and the plasma resistance deteriorates.

[0008] In Patent Document 2, sintering aids of Zr, Si, Ce and Al are included. When multiple materials are included as sintering aids in the yttrium oxide sintered body, segregation of the sintering aid components occurs, and there is a risk of localized areas having poor plasma resistance. In addition, although the effect of the sintering aids is to lower the firing temperature, firing at about 1700°C is required to obtain a high-purity, dense yttrium oxide sintered body.

[0009] The present invention has been made in view of the above circumstances, and aims to provide an yttrium oxide sintered body that can be sintered at a low temperature and has excellent plasma resistance, a method for producing the same, and a component for semiconductor manufacturing equipment. [Means for solving the problem]

[0010] (1) In order to achieve the above object, the yttrium oxide sintered body of the present invention is an yttrium oxide sintered body, characterized in that it contains yttrium oxide as a main component, contains 0.1 mass% or more and 0.5 mass% or less of aluminum calculated as an oxide, has a content of metals other than yttrium and aluminum of 1000 ppm or less, and has a relative density of 98% or more.

[0011] In this way, by making the yttrium oxide sintered body contain a small amount of aluminum oxide in yttrium oxide and contain as few other metals as possible, the plasma resistance of the yttrium oxide sintered body can be made comparable to the plasma resistance of a high-purity (99.9% or more) yttrium oxide sintered body. In addition, since the relative density is sufficiently high, the plasma resistance can be increased, the strength as a sintered body is excellent, and it can be suitably used as a large member.

[0012] (2) In the yttrium oxide sintered body of the present invention, the yttrium oxide sintered body is characterized in that the average particle size is 1 μm or more and 10 μm or less.

[0013] By reducing the average particle size of the particles constituting the yttrium oxide sintered body in this manner, the risk of particle shedding of the yttrium oxide sintered body can be reduced, and a decrease in plasma resistance can be suppressed.

[0014] (3) In addition, the yttrium oxide sintered body of the present invention is characterized in that the yttrium oxide sintered body contains a composite oxide of yttrium and aluminum, and the composite oxide has an area ratio of 0.5% or more and 5% or less as confirmed in a SEM image of a cross section of the sintered body.

[0015] In this way, by setting the area ratio of the complex oxide observed in the SEM image to a predetermined range, the crystallinity of the yttrium oxide sintered body can be improved, and the plasma resistance can be further improved.

[0016] (4) The yttrium oxide sintered body of the present invention is characterized in that the contents of Si, Ca, and Na are each 150 ppm or less.

[0017] In this way, by minimizing the inclusion of Si, Ca, and Na, the plasma resistance of the yttrium oxide sintered body can be further improved, since Si, Ca, and Na have a particularly large effect on the plasma resistance.

[0018] (5) A semiconductor manufacturing equipment member of the present invention is characterized in that it comprises the yttrium oxide sintered body according to any one of (1) to (4) above.

[0019] As a result, a semiconductor manufacturing equipment component can be constructed using an yttrium oxide sintered body having high strength and a level of plasma resistance comparable to that of a high-purity yttrium oxide sintered body, and the cost of the semiconductor manufacturing equipment can be reduced.

[0020] (6) Furthermore, the method for producing an yttrium oxide sintered body of the present invention is a method for producing an yttrium oxide sintered body, which is characterized by including the steps of: weighing yttrium oxide and aluminum oxide so that the sintered body contains 99.4 mass% or more of yttrium oxide and 0.1 mass% to 0.5 mass% or less of aluminum, calculated as oxide, after sintering; adding a binder to the weighed materials and mixing them; granulating the mixed materials to form a granulated powder; molding the granulated powder to form a molded body; and firing the molded body at a temperature of 1500°C to 1700°C.

[0021] In this way, by adding only a small amount of aluminum oxide to yttrium oxide as a sintering accelerator, the resulting composite oxide is also a material with excellent plasma resistance, and the content is sufficiently reduced, so that the plasma resistance of the manufactured yttrium oxide sintered body can be made comparable to that of a high-purity (99.9% or more) yttrium oxide sintered body. In addition, since the aluminum oxide contained in yttrium oxide is generated as a composite oxide and sintering is promoted, sintering at a low temperature of 1700°C or less is possible, and the grain growth of the particles constituting the yttrium oxide sintered body can be suppressed. As a result, the risk of grain shedding of the yttrium oxide sintered body can be reduced, and the decrease in plasma resistance can be suppressed. In addition, by sintering at 1500°C or more, the relative density can be increased. As a result, the plasma resistance can be increased, the strength as a sintered body is excellent, and it can be suitably used as a large member.

[0022] (7) In the method for producing an yttrium oxide sintered body of the present invention, the aluminum oxide is added in the form of an alumina sol.

[0023] This improves the dispersibility of aluminum oxide and further suppresses grain growth of the grains constituting the sintered body, thereby further suppressing the deterioration of plasma resistance due to grain shedding. Effect of the Invention

[0024] According to the present invention, the plasma resistance of the yttrium oxide sintered body can be sufficiently increased. In addition, the manufacturing method thereof allows sintering at a low temperature, and can manufacture an yttrium oxide sintered body with sufficiently high plasma resistance. In addition, the member for semiconductor manufacturing equipment can have high plasma resistance, has excellent strength as a sintered body, and can be suitably used as a large member. [Brief description of the drawings]

[0025] [Figure 1] 1 is a schematic cross-sectional view showing an example of use of a semiconductor manufacturing equipment member according to an embodiment of the present invention. [Diagram 2] 1 is a flowchart showing an example of a manufacturing process for an yttrium oxide sintered body according to an embodiment of the present invention. [Diagram 3] 1 is a table showing the ratio of raw materials, sintering temperatures, and various evaluation results of sintered bodies of Examples, Comparative Examples, and Reference Examples. [Figure 4] 1 is an SEM image of an yttrium oxide sintered body of Example 1. [Diagram 5] 1 is an SEM image of an yttrium oxide sintered body of Example 6. [Figure 6] 1 is an SEM image of an yttrium oxide sintered body of Example 7. [Figure 7] 1 is an SEM image of the sintered body of Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Next, an embodiment of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are used for the same components in each drawing, and duplicated descriptions will be omitted. In the configuration diagrams, the size of each component is conceptually shown, and does not necessarily represent the actual dimensional ratio.

[0027] [Composition of yttrium oxide sintered body] The yttrium oxide sintered body of the present invention is mainly composed of yttrium oxide (Y2O3), contains 0.1 mass% or more and 0.5 mass% or less of aluminum calculated as oxide (Al2O3), and contains 1000 ppm or less of metals other than yttrium and aluminum. "Mainly composed of yttrium oxide" means that it contains 99.4 mass% or more and less than 99.9 mass% of yttrium oxide.

[0028] In this way, by making the yttrium oxide sintered body into one that contains a small amount of aluminum oxide and contains as few other metals as possible, it is possible to make the plasma resistance of the body comparable to that of high-purity (99.9% or more) yttrium oxide sintered bodies.

[0029] If the content of aluminum oxide is less than 0.1% by mass, the effect of promoting sintering is small, and densification by low-temperature sintering at 1700°C or less is difficult. By sintering at a low temperature, the grain growth of the grains constituting the sintered body can be suppressed, and the decrease in plasma resistance due to grain shedding can be suppressed. In addition, lowering the sintering temperature also leads to protection of the sintering furnace and reduction in manufacturing costs. In addition, if the content of aluminum oxide exceeds 0.5% by mass, segregation of aluminum oxide may occur, and if segregation of aluminum oxide occurs, plasma resistance is impaired. For these reasons, the content of aluminum oxide is set to the above range. Therefore, the content of aluminum oxide is preferably 0.2% by mass or more. In addition, the content of aluminum oxide is preferably 0.4% by mass or less, and more preferably 0.3% by mass or less.

[0030] In addition, by setting the content of metals other than yttrium and aluminum to 1000 ppm (0.1 mass%) or less, plasma resistance can be sufficiently ensured. These trace metals are easily condensed mainly in the grain boundary layer of the yttrium oxide sintered body, and are more likely to corrode in a plasma environment than yttrium oxide or aluminum oxide. If the corrosion of the trace metal components progresses first, the corrosion of the grain boundary portion causes particles to fall off, and the plasma resistance deteriorates. For this reason, it is preferable that the content of metals other than yttrium and aluminum is as small as possible. Therefore, the content of metals other than yttrium and aluminum is preferably 500 ppm or less, more preferably 300 ppm or less.

[0031] In this way, by including only aluminum oxide without including other auxiliary components, it is possible to suppress localized reduction in plasma resistance caused by other compositions with inferior plasma resistance, and to equalize the plasma resistance of the component. Note that, in order to keep the trace metal content within the above range, it is necessary to control so that impurities are not mixed in from the raw material powder or the manufacturing process.

[0032] In addition, the yttrium oxide sintered body has a relative density of 98% or more. Since the relative density is sufficiently high, the plasma resistance can be increased, the strength of the sintered body is excellent, and the sintered body can be suitably used as a large member.

[0033] The relative density of yttrium oxide sintered bodies can be expressed as (sintered body density / theoretical density) × 100 (%). Theoretical density is the density of yttrium oxide alone (5.01 g / cm 3 ) and the density of the sintered body was measured by the Archimedes method for the density of the yttrium oxide sintered body.

[0034] The yttrium oxide sintered body preferably has an average particle size of 1 μm or more and 10 μm or less. By reducing the average particle size of the particles constituting the yttrium oxide sintered body in this way, the risk of the yttrium oxide sintered body being shed can be reduced, and the deterioration of plasma resistance can be suppressed.

[0035] The average particle diameter of the yttrium oxide sintered body refers to the average particle diameter of the particles constituting the yttrium oxide sintered body. This can be done by polishing the cross section of the yttrium oxide sintered body, thermally etching the polished surface, taking an image with a scanning electron microscope (SEM), and using image analysis software WinROOF (manufactured by Mitani Shoji Co., Ltd.) to calculate the circle equivalent diameter of the obtained image, and measuring the average particle diameter in that field of view. This operation should be performed in 3 to 5 fields of view, and the average value in each field of view should be taken as the average particle diameter.

[0036] The yttrium oxide sintered body also contains a composite oxide made of yttrium and aluminum, and the composite oxide preferably has an area ratio of 0.5% to 5% as confirmed in an SEM image of the cross section of the yttrium oxide sintered body. In this way, by setting the area ratio of the composite oxide observed in the SEM image within a predetermined range, the crystallinity of the yttrium oxide sintered body can be improved, and the plasma resistance can be further improved. Furthermore, the reaction occurring when the composite oxide made of yttrium and aluminum is generated in the sintered body promotes sintering, and thus the firing temperature can be reduced. The composite oxide made of yttrium and aluminum is YAG (Y3Al5O 12 ), YAP (YAlO3), YAM (Y4Al2O9), etc.

[0037] The area ratio of the composite oxide can be confirmed by photographing the cross section of the sintered body at 1000x magnification with a scanning electron microscope (SEM) and calculating it by processing the obtained photograph using image analysis software WinROOF (Mitani Shoji Co., Ltd.). It can be measured by binarizing a 100μm×100μm field of view from the photographed image data. It is sufficient to observe 3 to 5 fields of view randomly as measurement points.

[0038] The generation of a composite oxide of yttrium and aluminum can be confirmed by measuring the cross section of the yttrium oxide sintered body with high-power XRD. After confirming the composition of particles with different contrast in the SEM image by high-power XRD measurement, the area ratio of the composite oxide can be confirmed by targeting the particles confirmed to be composite oxide and performing the above image analysis. Note that the area of ​​pores displayed as black particles in the cross-sectional SEM image is calculated by excluding it from the total area.

[0039] In addition, the yttrium oxide sintered body preferably has a Si, Ca, and Na content of 150 ppm or less. In this way, by minimizing the inclusion of Si, Ca, and Na, the plasma resistance of the yttrium oxide sintered body can be further improved. This is because Si, Ca, and Na have a particularly large effect on the plasma resistance. Therefore, the Si, Ca, and Na contents are more preferably 100 ppm or less, and even more preferably 50 ppm or less. The metal content in the yttrium oxide sintered body can be measured by glow discharge mass spectrometry (GDMS).

[0040] [Configuration of semiconductor manufacturing equipment parts] Next, the semiconductor manufacturing equipment member of the present invention will be described. Fig. 1 is a schematic cross-sectional view showing an example of use of the semiconductor manufacturing equipment member according to the embodiment of the present invention. The semiconductor manufacturing equipment member of the present invention is used as a gas nozzle 10 used in a plasma device 100 such as a film forming device for forming a thin film on a substrate W such as a semiconductor wafer or a glass substrate, or an etching device for performing microfabrication on the substrate W, for example, in a semiconductor manufacturing process or a liquid crystal manufacturing process.

[0041] For example, in a film forming apparatus, a raw material gas containing a corrosive gas is introduced into a reaction vessel 20 using a gas nozzle 10, and the raw material gas is converted into plasma by a plasma CVD (Chemical Vapor Deposition) method to form a thin film on a substrate W. In an etching apparatus, a halogen-based corrosive gas is introduced into a reaction vessel 20 using a gas nozzle 10 as a raw material gas, and the corrosive gas is converted into plasma to form an etching gas, thereby performing microfabrication on the substrate W.

[0042] The gas nozzle 10 has a gas supply port 11 through which gas such as a corrosive gas is supplied from a gas supply unit not shown, a gas exhaust port 12 through which gas is exhausted into the reaction vessel 20, and a nozzle hole 13 which connects the gas supply port 11 and the gas exhaust port 12.

[0043] The semiconductor manufacturing equipment member according to the embodiment of the present invention is a member having a portion exposed to a corrosive gas, and in this embodiment, it is a member constituting at least a portion of the portion of the gas nozzle 10 exposed to the corrosive gas, for example, the portion including the nozzle hole 13 and the portion exposed inside the reaction vessel 20. However, the semiconductor manufacturing equipment member may constitute the entire gas nozzle 10. In addition, the corrosion-resistant member may be, for example, the vessel body 21 or the lid 22 constituting the reaction vessel 20, or a portion thereof.

[0044] [Method of manufacturing yttrium oxide sintered body] Next, a method for producing an yttrium oxide sintered body according to the present invention will be described. Fig. 2 is a flow chart showing an example of a process for producing an yttrium oxide sintered body according to an embodiment of the present invention.

[0045] First, yttrium oxide powder and aluminum oxide powder are prepared as raw material powders for the yttrium oxide sintered body. The purity of each powder is preferably 99.9% or more, more preferably 99.99% or more. The average particle size of each powder is preferably 0.1 μm or more and 2.0 μm or less. Next, each powder is weighed so that the aluminum content in the yttrium oxide sintered body after sintering is a predetermined value in the range of 0.1 mass% to 0.5 mass% in terms of oxide (STEP 1).

[0046] Next, the raw material powders are mixed. For example, each powder is put into a pot together with a binder (PVA, etc.), and is pulverized and mixed by wet mixing using a ball mill to prepare a raw material slurry (STEP 2). Ion-exchanged water and a dispersant may be used to prepare the raw material slurry. For example, alumina balls may be used for the ball mill. The mixing time may be, for example, 20 hours.

[0047] Next, the slurry obtained in the mixing step is dried and granulated (STEP 3). For example, a method of obtaining a granulated powder from the slurry can be mentioned in which the slurry is dried in a hot water bath to remove the solvent from the slurry to obtain a powder, and the obtained powder is passed through a sieve. A spray dryer can also be used.

[0048] Next, the granulated powder obtained in the granulation step is molded to form a molded body (STEP 4). The molding method may be a method in which the granulated powder obtained is put into a mold and press molded. As the press molding method, molding may be performed by a known method such as uniaxial press molding, cold isostatic pressing (CIP), hot pressing, etc. In addition, the molding pressure may be, for example, 98 MPa in the case of press molding.

[0049] Next, the molded body is fired (STEP 5). The molded body is fired in an oxidizing atmosphere or a vacuum atmosphere at a temperature of 1500°C to 1700°C to obtain an yttrium oxide sintered body. The firing time is preferably 1 hour to 20 hours. If necessary, a degreasing step may be added before the firing step. Also, a step of compressing the yttrium oxide sintered body using HIP to densify it may be provided.

[0050] It is preferable that the raw material aluminum oxide is prepared in the form of an alumina sol and added in the form of an alumina sol. This improves the dispersibility of the aluminum oxide and further suppresses the grain growth of the grains constituting the sintered body. As a result, it is possible to further suppress the deterioration of plasma resistance due to grain shedding.

[0051] By such a process, it is possible to produce an yttrium oxide sintered body having plasma resistance equivalent to that of a high-purity yttrium oxide sintered body.

[0052] [Examples and Comparative Examples] Example 1 Yttrium oxide raw powder (purity 99.9%, average particle size 1 μm) and aluminum oxide raw powder (purity 99.99%, average particle size 0.2 μm) were weighed so that aluminum oxide was contained in the yttrium oxide sintered body at 0.1 mass%. Next, the weighed raw powder was charged into a pot together with 2.0 mass% of PVA binder as a binder, 0.3 mass% of water-soluble acrylic dispersant as a dispersant, and an appropriate amount of ion-exchanged water, and a raw material slurry was formed by wet mixing using a ball mill. Next, this raw material slurry was dried and granulated using a spray dryer. Next, the granulated powder was charged into a mold, and a molded body was produced by cold isostatic pressing (CIP). Next, the obtained molded body was fired at a temperature of 1600 ° C. in an air atmosphere for 10 hours to obtain the yttrium oxide sintered body of Example 1.

[0053] Example 2 An yttrium oxide sintered body of Example 2 was produced under the same conditions as those of Example 1, except that aluminum oxide was weighed out so as to be contained in the sintered body at 0.2 mass %.

[0054] Example 3 An yttrium oxide sintered body of Example 3 was produced under the same conditions as those of Example 1, except that aluminum oxide was weighed out so as to be contained in the sintered body at 0.3 mass %.

[0055] Example 4 An yttrium oxide sintered body of Example 4 was produced under the same conditions as those of Example 1, except that aluminum oxide was weighed out so as to be contained in the sintered body at 0.5 mass %.

[0056] Example 5 An yttrium oxide sintered body of Example 5 was produced under the same conditions as those of Example 2, except that the firing was performed at a temperature of 1500°C.

[0057] Example 6 An yttrium oxide sintered body of Example 6 was produced under the same conditions as those of Example 2, except that the firing was performed at a temperature of 1700°C.

[0058] Example 7 An yttrium oxide sintered body of Example 7 was produced under the same conditions as in Example 2, except that the aluminum oxide source was changed from powder to alumina sol (average particle size: 0.05 μm).

[0059] Example 8 An yttrium oxide sintered body of Example 8 was produced under the same conditions as in Example 2, except that the firing time was set to 1 hour.

[0060] Comparative Example 1 A sintered body of Comparative Example 1 made of yttrium oxide alone was produced under the same conditions as in Example 1, except that aluminum oxide was not added as a sintering aid.

[0061] Comparative Example 2 A sintered body of Comparative Example 2 containing yttrium oxide and aluminum oxide was produced under the same conditions as in Example 1, except that the aluminum oxide contained in the sintered body was weighed out to be 0.6 mass %.

[0062] Comparative Example 3 A sintered body of Comparative Example 3 containing yttrium oxide and aluminum oxide was produced under the same conditions as in Example 2, except that a metal other than aluminum was intentionally added so as to be outside the range of the present invention.

[0063] Comparative Example 4 A sintered body of Comparative Example 4 was produced under the same conditions as in Example 2, except that the sintering was carried out at a temperature of 1400°C.

[0064] (Reference example 1, reference example 2) Using the raw material powders used in Example 1, a sintered body of Reference Example 1 made of simple yttrium oxide and a sintered body of Reference Example 2 made of simple aluminum oxide were produced so that the relative density of the sintered body was 98.0% or more.

[0065] (Evaluation method) A plurality of test pieces were cut out from the sintered bodies of the Examples, Comparative Examples, and Reference Examples, and the following measurements were carried out.

[0066] (1) Confirmation of the content of aluminum oxide and metal impurities in the sintered body The aluminum oxide and other metal contents in the sintered body of each test piece were confirmed by glow discharge mass spectrometry (GDMS).

[0067] (2) Measurement of relative density of sintered body The sintered density of each test piece was measured by the Archimedes method. The relative density was calculated by (sintered density / theoretical density)×100(%). The theoretical density was calculated based on the density of yttrium oxide alone (5.01 g / cm3) in the examples, comparative examples, and reference example 1. 3 In Reference Example 2, the density of aluminum oxide alone (4.0 g / cm 3 ) was decided.

[0068] (3) Calculation of average particle size The cross section of each test piece was photographed with a SEM at 1000x magnification, and the obtained photograph was analyzed using image analysis software WinROOF (Mitani Shoji Co., Ltd.) to calculate the average particle size by calculating the circle equivalent diameter. Measurement points were randomly selected from three fields of view.

[0069] (4) Confirmation of the area ratio of the composite oxide in the sintered body High-power XRD confirmed that a composite oxide made of yttrium and aluminum was generated. The area ratio of the composite oxide made of yttrium and aluminum was measured by photographing the cross section of each test piece with a SEM at 1000x magnification and processing the resulting photographs using image analysis software WinROOF (Mitani Shoji Co., Ltd.). The measurement points were randomly observed in three fields of view of 100μm×100μm from the photographed image data.

[0070] (5) Plasma resistance test One side of each test piece was mirror-polished, a part of it was masked with polyimide tape, and then each test piece was placed in a plasma etching device. Then, plasma treatment was performed in the RIE etching device under the conditions of NF3 as etching gas, plasma exposure time of 4 hours, and high frequency output of 2000 W, and the corrosion depth before and after the plasma treatment was confirmed by comparing it with the masked part. At this time, corrosion depths of 0.7 μm or less were evaluated as particularly excellent (◎), and those exceeding 0.7 μm and not exceeding 0.8 μm were evaluated as excellent (○) and passed. Those larger than that were evaluated as poor (×) and failed.

[0071] (Evaluation Results) The table in Fig. 3 shows the ratio of raw materials, sintering temperature, and various evaluation results of the sintered bodies of the Examples, Comparative Examples, and Reference Examples. As shown in the table in Fig. 3, it was confirmed that Examples 1 to 8, which are yttrium oxide sintered bodies of the present invention, have plasma resistance equivalent to that of Reference Example 1, a sintered body made of simple yttrium oxide with a relative density of 99.9% sintered at 1700°C.

[0072] In the yttrium oxide sintered body of the embodiment, only the crystalline phase of Y2O3 was confirmed by X-ray diffraction (XRD), and neither the crystalline phase of a composite oxide of yttrium and aluminum nor the crystalline phase of aluminum oxide was confirmed. Furthermore, the crystalline phase of aluminum oxide was not confirmed by measurement using high-power XRD. That is, although the yttrium oxide sintered body of the embodiment contains aluminum oxide, which has poor plasma resistance, it is mostly yttrium oxide, and the added aluminum oxide is a composite oxide with yttrium oxide, which has better plasma resistance than aluminum oxide alone. This is thought to be the reason why the plasma resistance of the yttrium oxide sintered body of the present invention is comparable to that of a high-purity yttrium oxide sintered body.

[0073] Among Examples 1 to 4 in which the aluminum oxide content was changed, Examples 2 and 3 showed particularly excellent plasma resistance. Also, Example 7 in which the aluminum oxide source was mixed as an alumina sol showed excellent plasma resistance. It is believed that the reason for the improvement in plasma resistance in Examples 2 and 3 is that the amount of aluminum oxide added was more preferable. It is believed that the reason for the improvement in plasma resistance in Example 7 is that the amount of aluminum oxide added was more preferable and the average particle diameter was controlled to be smaller. Figures 4 to 6 are SEM images of the yttrium oxide sintered bodies of Examples 1, 6, and 7, respectively.

[0074] On the other hand, as shown in the table of FIG. 3, in Comparative Example 1, which does not contain aluminum oxide as a sintering aid, dense sintering could not be achieved at the same firing temperature as in Example 1. Also, as can be seen from FIG. 7, many pores remained in the sintered body. FIG. 7 is an SEM image of the sintered body of Comparative Example 1. The black dots in these figures indicate pores. The sintered body of Comparative Example 1 did not achieve good plasma resistance in the plasma resistance test. This is thought to be due to the progress of corrosion due to the many pores.

[0075] In Comparative Example 2, in which the content of aluminum oxide exceeded the range of the present invention, good plasma resistance was not obtained compared to the Examples and Reference Example 1. This is considered to be because a part of the aluminum oxide caused segregation.

[0076] In Comparative Example 3, in which the content of metals other than yttrium and aluminum was outside the range of the present invention, good plasma resistance was not obtained compared to the Examples. This is believed to be because the sample contained a large amount of materials that have inferior plasma resistance to yttrium oxide and aluminum oxide.

[0077] The sintered body of Comparative Example 4, which was sintered at a low sintering temperature, did not become dense, and therefore the relative density was significantly low. Furthermore, the generation of a composite oxide made of yttrium and aluminum could not be confirmed. This is believed to be because the solid solution of aluminum oxide in yttrium oxide did not progress. Furthermore, the plasma resistance also deteriorated. This is believed to be because the relative density was low, the generation of a composite oxide did not progress, and the structure was in a necking state.

[0078] From the above results, it was confirmed that the yttrium oxide sintered body of the present invention has sufficiently high plasma resistance. It was also confirmed that the manufacturing method thereof allows sintering at low temperatures and can manufacture an yttrium oxide sintered body with sufficiently high plasma resistance. It was also confirmed that the semiconductor manufacturing equipment member can have high plasma resistance, has excellent strength as a sintered body, and can be suitably used as a large member.

[0079] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications and equivalents are included within the spirit and scope of the present invention. In addition, the structure, shape, number, position, size, etc. of the components shown in each drawing are for convenience of explanation and may be changed as appropriate. [Explanation of symbols]

[0080] 10 Gas nozzle 11 Gas supply port 12 Gas exhaust port 13 Nozzle hole 20 Reaction vessel 21 Container body 22 Lid 100 Plasma device W substrate

Claims

1. An yttrium oxide sintered body, The main component is yttrium oxide. Contains 0.1% by mass or more and 0.5% by mass or less of aluminum in terms of oxide, The content of metals other than yttrium and aluminum is 1000 ppm or less; The relative density is 98% or more, The average particle size is 1 μm or more and 10 μm or less, A composite oxide of yttrium and aluminum is included, The composite oxide has an area ratio of 0.5% or more and 5% or less as confirmed in a SEM image of a cross section of the sintered body, An yttrium oxide sintered body comprising at least one of Ca and Na, the Si, Ca and Na contents each being 150 ppm or less.

2. A semiconductor manufacturing equipment member comprising the yttrium oxide sintered body according to claim 1.

3. A method for producing an yttrium oxide sintered body, comprising the steps of: The yttrium oxide sintered body is The average particle size is 1 μm or more and 10 μm or less, A composite oxide of yttrium and aluminum is included, The composite oxide has an area ratio of 0.5% or more and 5% or less as confirmed in a SEM image of a cross section of the sintered body, The manufacturing method includes: weighing yttrium oxide and aluminum oxide so that the yttrium oxide contains 99.4 mass% or more and aluminum contains 0.1 mass% or more and 0.5 mass% or less in terms of oxide after sintering; adding a binder to the weighed materials and mixing them; granulating the mixed material to form a granulated powder; forming a compact by molding the granulated powder; Sintering the molded body at a temperature of 1500° C. or more and 1700° C. or less; A method for producing an yttrium oxide sintered body, characterized in that the yttrium oxide weighed in the weighing step is a powder, and the average particle size of the weighed yttrium oxide powder is 0.1 μm or more and less than 0.3 μm.

4. 4. The method for producing an yttrium oxide sintered body according to claim 3, wherein the aluminum oxide is added in the form of an alumina sol.

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