Film-forming material suitable for members for plasma etching apparatus and the like and method for producing the same

Abstract

To provide a Y2O3 containing film deposition material suitable for a plasma etching device member and high in plasma resistance, and a method for manufacturing the same.SOLUTION: A film deposition material includes a solid solution including metal oxide consisting of ZrO2, HfO2 or Nb2O5 and Y2O3. When the metal oxide is ZrO2, the content of ZrO2 is 2-12 mol%; when the metal oxide is HfO2, the content of HfO2 is 4-24 mol%; when the metal oxide is Nb2O5, the content of Nb2O5 is 1-8 mol%; and the crystal structure of the solid solution has the regular hexahedron crystal structure of Y2O3.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a film-forming material suitable for a member for a plasma etching apparatus used in semiconductor manufacturing, a film-forming method using the film-forming material, a method for manufacturing a plasma etching apparatus, and a method for manufacturing the film-forming material.

Background Art

[0002] Plasma etching in semiconductor manufacturing is employed in the step of fabricating circuits on a wafer. Before starting plasma etching, the wafer is coated with a photoresist or a hard mask (usually an oxide or a nitride), and then exposed in accordance with a circuit pattern in a subsequent photolithography process (patterning process). In plasma etching, the selectively etched material is removed by subjecting the patterned wafer to plasma etching (etching process). This patterning process and etching process are repeated a plurality of times in the semiconductor manufacturing process. In plasma etching, not only the physical sputtering effect but also plasma using a halogen-based gas such as a fluorine-based or chlorine-based gas is irradiated onto the wafer to remove the etched material by combining the chemical sputtering effect.

[0003] In plasma etching, as a highly integrated semiconductor circuit is formed, it is necessary to create a substantially vertical profile, so high-energy and high-density ions and radicals are emitted from the plasma. For this reason, not only the wafer to be etched but also the material constituting the inner surface of the chamber where etching is performed is affected by plasma irradiation and consumed. And the particles thus generated adhere to the circuit on the wafer, contributing to a reduction in the yield of semiconductor chip manufacturing.

[0004] Generally, the materials constituting the chamber for plasma etching are metal materials such as aluminum alloys, and their resistance to exposure to halogen-based gas plasmas is not high. Therefore, the chamber is coated with a plasma-resistant material to suppress the chamber from being eroded by the plasma and generating particles. Examples of the plasma-resistant material coated on the chamber include ceramic materials. Ceramic materials such as metal oxides have a complex crystal structure and high chemical stability, so they exhibit good durability against plasma exposure.

[0005] Among ceramic materials, in particular, yttrium oxide (Y2O3) has been found to have high plasma resistance against halogen-containing plasmas of the type used in the fabrication of semiconductor devices. For example, in Patent Document 1, a method of coating the surface of a substrate such as metal, ceramic, or carbon material inside a plasma processing vessel with a Y2O3 sprayed film has been proposed to provide an internal member of the plasma processing vessel with excellent plasma erosion resistance.

[0006] Also, in Patent Document 2, a method has been proposed to obtain a film having both plasma resistance and low electrical resistance by flame spraying, thermal spraying, or plasma spraying a precursor oxide for forming a Y2O3-containing solid solution film on the surface of a semiconductor processing apparatus or the like by a spraying process. And in this case, as the precursor oxide, at least one other oxide selected from the group consisting of ZrO2, CeO2, HfO2, Nb2O5, Sc2O3, Nd2O3, Sm2O3, Yb2O3, Er2O3 and combinations thereof, and at least two mixed oxides of Y2O3 are proposed to be used.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] In recent years, as is well known, semiconductors used in advanced technology fields have been increasingly highly integrated, and the line width of the circuits formed on the chips is required to be 20 nm or less. For this reason, minute particles having a size of about several tens of nm, which did not cause problems in plasma etching before, have also become a problem, and the required level for plasma resistance has become stricter than before.

[0009] However, as a result of the research conducted by the present inventors, it cannot be said that the materials described in Patent Document 1 sufficiently satisfy the high required level of plasma resistance in recent years. In addition, the Y2O3-containing solid solution film formed by the spraying method described in Patent Document 2 has its improvement purpose in the low electrical resistivity which is the electrical property of the film, and the plasma resistance of the film is the same as that of Y2O3 and is not particularly improved. This is also clarified from Patent Document 2. That is, Patent Document 2 shows the erosion rate representing the plasma resistance of the Y2O3-containing solid solution samples 1 to 4 in "Table 1" in its attached FIG. 5, but the plasma resistance of those samples 1 to 4 is reported to be the same as that of pure Y2O3, although it is better than conventional materials such as Al2O3, AlN, and ZrO2.

[0010] The present invention has been made under such circumstances, and an excellent Y2O3-containing solid solution film-forming material having higher plasma resistance characteristics, which is suitable as a member for a plasma etching apparatus such as a semiconductor manufacturing process, a film-forming method using the film-forming material, a manufacturing method of a member for a plasma etching apparatus, and a manufacturing method of the film-forming material are provided as problems to be solved.

Means for Solving the Problems

[0011] In order to achieve the above object, the present inventor conducted research on the plasma resistance of a film-forming material containing Y2O3. As a result, a film-forming material containing a solid solution containing Y2O3 and a specific metal oxide was obtained. The specific metal oxide is ZrO2, HfO2, or Nb2O5, the content of these metal oxides contained in the solid solution is in a specific range, respectively, and when the crystal structure of the solid solution has a regular hexahedron crystal structure of Y2O3, the plasma resistance characteristics of this Y2O3-containing material are improved and the erosion (consumption) rate is reduced.

[0012] The present invention is based on such new findings and has the following aspects. (1) A film-forming material containing a solid solution containing a metal oxide composed of ZrO2, HfO2 or Nb2O5 and Y2O3, wherein when the metal oxide is ZrO2, the content of ZrO2 is 2 to 12 mol%, when the metal oxide is HfO2, the content of HfO2 is 4 to 24 mol%, when the metal oxide is Nb2O5, the content of Nb2O5 is 1 to 8 mol%, and the crystal structure of the solid solution has a regular hexahedron crystal structure of Y2O3.

[0013] (2) The film-forming material according to (1) above, wherein when the metal oxide is ZrO2, the content of ZrO2 is 7 to 12 mol%. (3) The film-forming material according to (1) above, wherein when the metal oxide is HfO2, the content of HfO2 is 8 to 20 mol%. (4) The film-forming material according to (1) above, wherein when the metal oxide is Nb2O5, the content of Nb2O5 is 3 to 7 mol%.

[0014] (5) The film-forming material according to any one of (1) to (4) above, wherein the ratio of Zr, Hf or Nb atoms to Y atoms contained in the solid solution is within ±5% of the absolute value at five randomly selected points of the solid solution contained in the film-forming material. (6) The film-forming material according to any one of (1) to (5) above, wherein the solid solution produces only peaks of the regular hexahedron crystal structure of Y2O3 in X-ray diffraction (XRD). (7) A film-forming method of spraying using the film-forming material according to any one of (1) to (6) above. (8) A film-forming method of physical vapor deposition using the film-forming material according to any one of (1) to (6) above. (9) A method for manufacturing a member for a plasma etching apparatus, which forms a protective film on a substrate by the film-forming method according to (7) or (8) above.

[0015] (10) A method for manufacturing the film-forming material according to any one of (1) to (9) above, which is a mixed powder of a metal oxide powder composed of ZrO2, HfO2 or Nb2O5 and Y2O3 powder. When the metal oxide is ZrO2, a mixed powder with a ZrO2 content of 2 to 12 mol% is heat-treated at 1000 to 1600 °C to form a solid solution. When the metal oxide is HfO2, a mixed powder with an HfO2 content of 4 to 24 mol% is heat-treated at 1200 to 1600 °C to form a solid solution. When the metal oxide is Nb2O5, a mixed powder with an Nb2O5 content of 1 to 8 mol% is heat-treated at 1200 to 1600 °C to form a solid solution. A method for manufacturing a film-forming material, characterized by the above. (11) After forming the above solid solution, granulate it into particles having an average particle size of 15 to 40 μm and heat-treat it at a temperature of 1200 to 1500 °C. The method for manufacturing a film-forming material according to (10) above. (12) A method for manufacturing the film-forming material according to any one of (1) to (9) above, which uses a mixed liquid containing a metal oxide sol containing ZrO2, HfO2 or Nb2O5 and Y2O3 powder as a raw material for spray drying granulation, and heat-treats spherical particles composed of primary particles of the obtained ZrO2 fine particles and Y2O3 fine particles at a temperature of 1000 to 1500 °C in an oxidizing atmosphere to form a solid solution. A method for manufacturing a film-forming material, characterized by the above.

Advantages of the Invention

[0016] According to the present invention, there are provided a Y2O3-containing solid solution film-forming material having high plasma resistance, which is suitable for forming a device such as a chamber used for dry etching by plasma generated from a gas containing a halogen such as fluorine, protecting the inner surface of the device from the plasma, and suppressing dust generated during the process, a film-forming method using the film-forming material, and a manufacturing method of the film-forming material. Furthermore, there is provided a manufacturing method of a member for a plasma etching apparatus having high plasma resistance, such as a chamber used for dry etching by plasma generated from a gas containing a halogen such as fluorine.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

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Figure 5a

Figure 5b

Figure 6a

Figure 6b

Figure 7a

Figure 7b

Embodiments for Carrying Out the Invention

[0018] The following describes in detail the embodiments for carrying out the present invention. In this specification (including the claims), when describing a numerical range, when the units of the upper and lower limits are the same, for example, "2 mol% to 12 mol%" may be described as "2 to 12 mol%", and "1000 °C to 1600 °C" may be described as "1000 to 1600 °C", and the description of the unit of the lower limit may be omitted in some cases. <Film-forming material> The film formed using the Y2O3-containing solid solution film-forming material of the present invention has high plasma resistance, which has been achieved through the following process. Y2O3, which is the main constituent of the film-forming material of the present invention, is widely used in semiconductor manufacturing processes and the like, and is known as one of the materials with the highest resistance to fluorine-containing plasma. Here, as shown in FIG. 1, although the unit cell of Y2O3 has a regular hexahedron structure in which oxygen can be 8-coordinated, oxygen in Y2O3 is 6-coordinated. The present inventor considered that many oxygen vacancies exist in the crystal from this fact, and whether the plasma resistance of Y2O3 can be further improved by arranging oxygen in some way in these oxygen vacancies to reduce the defects.

[0019] Therefore, the present inventor tried to arrange oxygen in the aforementioned oxygen vacancies to reduce the defects by adding other metal oxides to Y2O3. As a result, the present inventor found that when the metal oxide added to Y2O3 satisfies the following two requirements a and b, the consumption rate of the metal oxide - Y2O3 composite solid solution due to plasma exposure is significantly reduced, and the plasma resistance characteristics are improved. a. Oxygen in the crystal lattice structure of the metal oxide is 8-coordinated or 10-coordinated. b. Even when the metal oxide is added to Y2O3 in an amount of 1 mol% or more, the regular hexahedron crystal structure of Y2O3 is maintained.

[0020] In the present invention, among the metal oxides added to Y2O3, ZrO2 and HfO2 are metal oxides in which oxygen is 8-coordinated, and Nb2O5 is a metal oxide in which oxygen is 10-coordinated. Note that FIG. 2 is a binary phase diagram of Y2O3 and ZrO2, FIG. 3 is a binary phase diagram of Y2O3 and HfO2, and FIG. 4 is a binary phase diagram of Y2O3 and Nb2O5. From these binary phase diagrams, it is suggested that even if a small amount of ZrO2, HfO2 or Nb2O5 is added to Y2O3, the regular hexahedron crystal structure of Y2O3 is maintained.

[0021] Also, ZrO2 and HfO2 are metal oxides in which oxygen atoms are 8-coordinated, but tend to release oxygen atoms due to temperature changes and the like. Therefore, by dissolving ZrO2 or HfO2 in Y2O3, the oxygen atoms released from ZrO2 or HfO2 are arranged in the oxygen vacancies of Y2O3, making it possible to reduce defects. However, when the amount of ZrO2 or HfO2 added is large, Y2O3 cannot maintain the regular hexahedron structure, and as a result, the plasma resistance decreases.

[0022] Also, Nb2O5 is a metal oxide in which oxygen atoms are 10-coordinated, but tends to release oxygen atoms due to temperature changes and the like. Therefore, by dissolving Nb2O5 in Y2O3, the oxygen atoms released from Nb2O5 are arranged in the oxygen vacancies of Y2O3, making it possible to reduce defects. However, when the amount of Nb2O5 added is large, Y2O3 cannot maintain the regular hexahedron structure, and as a result, the plasma resistance decreases.

[0023] Thus, when a metal oxide in which oxygen is 8-coordinated or 10-coordinated is added to Y2O3 in a ratio that maintains the regular hexahedron crystal structure of Y2O3, oxygen is introduced into the oxygen vacancies in the crystal, so that the defect density decreases and the stability of the crystal improves. As a result, it is considered that the resistance of this crystal to physical sputtering and chemical sputtering increases.

[0024] The film-forming material of the present invention is a material obtained by dissolving a metal oxide composed of ZrO2, HfO2, or Nb2O5 in Y2O3. In this case, as described above, the amount dissolved in Y2O3 is important because it is related to the plasma resistance. Whether the content of the metal oxide is small or, conversely, large, the improvement in the plasma resistance of the resulting solid solution is small. In the present invention, Y2O3 may be referred to as the main oxide, and the added metal oxide composed of ZrO2, HfO2, or Nb2O5 may be referred to as the sub-oxide.

[0025] When the metal oxide is ZrO2, in the solid solution, the content of ZrO2 is 2 to 12 mol%, preferably 7 to 12 mol%, more preferably 8 to 11 mol%. When the metal oxide is HfO2, in the solid solution, the content of HfO2 is 4 to 24 mol%, preferably 8 to 20 mol%, more preferably 10 to 16 mol%. Also, when the metal oxide is Nb2O5, in the solid solution, the content of Nb2O5 is 1 to 8 mol%, preferably 3 to 7 mol%, more preferably 4 to 6 mol%.

[0026] The crystal structure of the solid solution contained in the film-forming material of the Y2O3-containing solid solution having high plasma resistance characteristics of the present invention has a regular hexahedron crystal structure of Y2O3 as the raw material even when an added metal oxide composed of ZrO2, HfO2, or Nb2O5 is dissolved. In the present invention, the crystal structure can preferably be confirmed by X-ray diffraction (XRD). When the crystal structure of the solid solution has a regular hexahedron crystal of Y2O3, the X-ray diffraction (XRD) of the solid solution produces only the peaks of the regular hexahedron crystal structure of Y2O3. In this specification, in X-ray diffraction, the occurrence of only the peaks of the regular hexahedron crystal structure of Y2O3 means that while having the same peaks as the regular hexahedron crystal structure of Y2O3, it does not have the peaks of the metal oxides solid-solved in Y2O3. In other words, the diagram when the Y2O3-containing solid solution of the present invention is subjected to X-ray diffraction shows peaks at the same positions (positions shifted parallel thereto) as the diagram of the regular hexahedron structure of Y2O3, that is, it means that it has the same shape as the diagram of the regular hexahedron structure of Y2O3. Note that the magnitudes of the peaks in the X-ray diffraction diagrams of the two do not necessarily have to be the same.

[0027] <Method for manufacturing a film-forming material> A representative example of the method for manufacturing the Y2O3-containing solid solution film-forming material of the present invention will be described below. First, ZrO2 powder, HfO2 powder, or Nb2O5 powder and Y2O3 powder are pulverized and mixed using a device such as a rotary ball mill, and heat-treated at a high temperature in the air or an inert atmosphere using an electric furnace or the like to integrate (for example, sinter) with each other. That is, it has a step of integrating each other by heat-treating a mixed powder of Y2O3 powder and ZrO2 powder, HfO2 powder, or Nb2O5 powder.

[0028] However, in the case of a mixed powder of Y2O3 powder and ZrO2 powder, the content of ZrO2 is 2 to 12 mol%, preferably 7 to 12 mol%. In the case of a mixed powder of Y2O3 powder and HfO2 powder, the content of HfO2 is 4 to 24 mol%, preferably 8 to 20 mol%. In the case of a mixed powder of Y2O3 powder and Nb2O5 powder, the content of Nb2O5 is 1 to 8 mol%, preferably 3 to 7 mol%.

[0029] In the Y2O3-containing solid solution film-forming material of the present invention, it is preferable that the added metal oxides are uniformly solid-solved in the film-forming material, and according to the following manufacturing method, a uniform film-forming material can be obtained. The uniform film-forming material obtained in the present invention randomly selects 5 points for the solid solution particles contained in the film-forming material, determines the content ratio of the metal atoms constituting the added metal oxide to Y atoms for each point, and the variation of the metal atoms / Y atoms at all 5 points in such values is within ±5% with respect to the absolute value. Here, the absolute value refers to the theoretical value of the metal atoms / Y atoms when it is assumed that the added metal oxide is uniformly dissolved in the film-forming material. For example, in the case of a film-forming material obtained by dissolving 10 mol% of ZrO2 in Y2O3, the absolute value is 0.111. That the film-forming material obtained by dissolving 10 mol% of ZrO2 in Y2O3 is uniform means that at all 5 randomly selected points, the value of Zr atoms / Y atoms is in the range of 0.111 ± 0.00555.

[0030] As a method for determining the content rate of metal atoms in the solid solution, for example, a method using an inductively coupled plasma optical emission spectrometer can be mentioned. Thus, since it is uniformly dissolved at the stage of the film-forming material, a state where it is uniformly dissolved can also be maintained in the film after film formation, and variations in plasma resistance in the film can be suppressed.

[0031] Hereinafter, the manufacturing method of the Y2O3-containing solid solution film-forming material will be described taking the case where the metal oxide is ZrO2 as an example. The case where the metal oxide is HfO2 or Nb2O5 can also be produced by a manufacturing method according to this. The purity of the powders used when pulverizing and mixing Y2O3 powder and ZrO2 powder is preferably 99.5% by weight or more. Also, the average particle diameter (D50) of these powders subjected to the pulverizing and mixing step is preferably 4 μm or less, and the average particle diameter of the mixed powder obtained by pulverizing and mixing is preferably 2 μm or less.

[0032] The average particle size of the ZrO2 powder before heat treatment is preferably 1 / 3 or less, more preferably 1 / 5 of the average particle size of the Y2O3 powder. Since the mixing ratio of the ZrO2 powder is less than that of the Y2O3 powder, the contact points between the Y2O3 powder and the ZrO2 powder are correspondingly reduced. Therefore, by setting the average particle size of the ZrO2 powder within the above range of the average particle size of the Y2O3 powder, the contact opportunities between the Y2O3 powder and the ZrO2 powder can be increased. In this way, by performing heat treatment in a state where the contact opportunities between the Y2O3 powder and the ZrO2 powder are numerous, the solid-phase reaction is promoted, and it becomes possible to dissolve the ZrO2 powder into the Y2O3 powder in a short time.

[0033] The heat treatment when sintering the mixed powder of Y2O3 powder and ZrO2 powder is preferably carried out at 1100 °C to 1600 °C, more preferably 1300 to 1500 °C. Thereby, it becomes possible to make the solid-phase reaction rate between the Y2O3 powder and the ZrO2 powder sufficiently fast, and it also becomes possible to adjust the particle size of the sintered body after heat treatment. In addition, the heat treatment when sintering the mixed powder of Y2O3 powder and HfO2 powder, or the heat treatment when sintering the mixed powder of Y2O3 powder and Nb2O5 powder is preferably carried out at 1200 to 1600 °C, more preferably 1400 to 1600 °C. Thereby, it becomes possible to make the solid-phase reaction rate between the Y2O3 powder and the HfO2 powder, or the solid-phase reaction rate between the Y2O3 powder and the Nb2O5 powder sufficiently fast, and it also becomes possible to adjust the particle size of the sintered body after heat treatment. In addition, when heat treatment is carried out at a temperature lower than the above range, the homogenization of the structure cannot be sufficiently carried out, and the solid-phase reaction rate becomes slow, so the manufacturing time becomes very long. On the other hand, when treatment is carried out at a temperature higher than the above range, the sintering between Y2O3 particles becomes active, and as consolidation progresses, subsequent particle size adjustment and the like become difficult. The heat treatment time is preferably 3 to 12 hours, more preferably 5 to 8.

[0034] Next, the synthetic powder sintered together by heat treatment is loosened and added to a solvent or the like to form a slurry, and then granulated into spherical particles having an average particle size preferably of 15 to 40 μm by a spray drying method or the like. These granulated particles are heated in an oxidizing atmosphere using an electric furnace or the like, preferably at 1200 to 1500°C, more preferably at 1350 to 1500°C, to remove the organic binder and improve the fracture strength of the spherical particles, and then used as a film-forming material.

[0035] Note that the method for producing the film-forming material of the present invention is not limited to the above method. Other methods include a fine particle dispersion sol using a metal oxide as a dispersoid and a method using a metal salt. For example, a commercially available ZrO2 sol and Y2O3 powder are mixed so that the mixing ratio of Y2O3 and ZrO2 becomes the above-mentioned preferred predetermined ratio, and this mixed solution is used as a raw material for spray drying granulation to obtain spherical particles composed of primary particles of ZrO2 fine particles and Y2O3 fine particles. By heat-treating these spherical particles in an oxidizing atmosphere at a temperature preferably of 1000 to 1500°C, it is possible to simultaneously realize a reaction treatment for integration and an improvement in the fracture strength of the spherical particles, and the spherical particles after heat treatment are used as a film-forming material. Note that the above ZrO2 sol can be replaced with an HfO2 sol or an Nb2O5 sol and can also be used as a film-forming material in the same manner.

[0036] Furthermore, the method for producing the film-forming material of the present invention can also be achieved by an electrofusion and pulverization method. For example, Y2O3 powder and ZrO2 powder mixed in a predetermined mixing ratio are melted and cast by an electrofusion method, preferably at a temperature of 3000 to 4000°C, to obtain an ingot of a synthetic material in which the regular hexahedral crystal structure of Y2O3 is maintained due to the high-temperature history during melting. This ingot is sequentially pulverized using a device such as a jaw crusher or a ball mill and adjusted to a suitable particle size range to be used as a film-forming material.

[0037] <Film-forming method> As a method for forming a film of the film-forming material of the present invention, known methods such as a spraying method and a physical vapor deposition method can be mentioned. Each film-forming method will be described below. The film formed by the spraying method or the physical vapor deposition method using the film-forming material of the present invention has high plasma resistance.

[0038] Examples of the spraying method suitable for the present invention include an atmospheric pressure plasma spraying method and a reduced pressure plasma spraying method. Among them, the atmospheric pressure plasma spraying method is preferable. As the atmospheric pressure plasma spraying method suitable for the present invention, known ones can be used including the apparatus and conditions. For example, the following can be mentioned. Spraying apparatus: Plasma spraying gun (9MB manufactured by Sulzer Metco) Operating voltage: 65V Operating current: 700A Primary gas (Ar) flow rate: 60NL / min Secondary gas (H2) flow rate: 5NL / min Spraying distance: 140mm

[0039] Examples of the physical vapor deposition method suitable for the present invention include a sputtering method, an ion plating method, an arc ion plating method, an electron beam physical vapor deposition method, etc. Among them, the electron beam physical vapor deposition method is preferable. As the electron beam physical vapor deposition method suitable for the present invention, known ones can be used including the apparatus and conditions. For example, the following can be mentioned. Apparatus: Von Ardenne, Tuba150 Substrate temperature: 450°C Chamber pressure: 1.0Pa Operating voltage: 60kW

[0040] <Method for manufacturing a member for a plasma etching apparatus> The film-forming material of the present invention is applied to members for plasma etching apparatuses used in semiconductor manufacturing, etc. The member for a plasma etching apparatus in the present invention is a member that can be exposed to plasma during a plasma process, and examples thereof include internal members of an etching chamber and an electrostatic chuck. The plasma etching apparatus in the present invention has a cylindrical chamber, a plasma generation unit such as an electrode, and members such as an electrostatic chuck for holding a wafer. The wafer held on the electrostatic chuck in the chamber is subjected to an etching process by the action of the plasma generated by the plasma generation unit. At this time, the generated plasma acts not only on the wafer but also on the chamber internal members and the electrostatic chuck.

[0041] The member for a plasma etching apparatus in the present invention refers to a member such as the above-described chamber internal member and electrostatic chuck that can be exposed to plasma. These members for a plasma etching apparatus are required to have high plasma resistance in order to suppress the generation of fine particles generated by being exposed to plasma. Therefore, by forming a protective film using the film-forming material of the present invention on the base material of the member for a plasma etching apparatus by a spraying method or a physical vapor deposition method, the member for a plasma etching apparatus can be provided with high plasma resistance.

Example

[0042] Hereinafter, the present invention will be specifically described by way of examples. Note that the present invention is not limited to the following examples. In the present invention, the average particle size means the particle size (D50) at the integrated value of 50% in the particle size distribution determined by the laser diffraction / scattering method unless otherwise specified.

[0043] (Example 1) Y2O3 powder with an average particle size of 3.3 μm and ZrO2 powder with an average particle size of 1.0 μm were prepared. The two powders were dry-mixed using a planetary mill (using zirconia balls and a zirconia pot) so that the content of the ZrO2 powder was 2 mol% in the resulting mixture of the Y2O3 powder and the ZrO2 powder. The obtained mixed powder was heated in an electric furnace at 1500 °C for 10 hours and subjected to a solid solution synthesis treatment. Next, the powder after the synthesis treatment was crushed using an alumina mortar and pestle, and a sintered body (solid solution) was produced using the crushed powder by a spark plasma sintering apparatus.

[0044] Next, the surface of the fabricated sintered body was polished with wet emery paper (SiC abrasive grains) up to #1200, and the crystal phase was identified by X-ray diffraction method (XRD). Finally, the sintered body subjected to the X-ray diffraction method was subjected to a plasma exposure test, and the erosion rate was measured. Here, the erosion rate was defined as follows based on the magnitude of the step measured using a laser microscope between the masked part that was not exposed to the plasma and the exposed part on the surface of the sintered body. Erosion rate = Magnitude of step (μm) / Etching time (min)

[0045] For the plasma exposure test, a dry etching apparatus was used, and the sintered body was placed still on a 4-inch Si wafer and exposed to the plasma. The plasma was generated under the following conditions. Plasma gas species and flow rate: CF4···50 sccm, O2···10 sccm, Ar···50 sccm RF output···800 W, Bias···600 W

[0046] (Example 2) A sintered body was fabricated, the crystal phase was identified, a plasma exposure test was conducted, and the erosion rate was measured in the same manner as in Example 1, except that the content of ZrO2 powder in the mixture of Y2O3 powder and ZrO2 powder was adjusted to 5 mol%.

[0047] (Example 3) A sintered body was fabricated, the crystal phase was identified, a plasma exposure test was conducted, and the erosion rate was measured in the same manner as in Example 1, except that the content of ZrO2 powder in the mixture of Y2O3 powder and ZrO2 powder was adjusted to 10 mol%. In Example 3, five points were randomly selected from among the obtained sintered powder particles, and the content ratio of Zr atoms to Y atoms was examined for each point. As a result, they were 0.1123, 0.1088, 0.1075, 0.1115, and 0.1135, respectively. Since the absolute value of the material obtained by solid-solubilizing 10 mol% of ZrO2 with respect to Y2O3 is 0.111, it was found that ZrO2 was uniformly solid-solubilized in the powder material in this example. Here, the XRD diagram used for identifying the crystal phase of the solid solution in Example 3 is shown in Fig. 5(a). It can be seen from Fig. 5(a) that only the peaks of the regular hexahedron crystal structure of Y2O3 are generated in the solid solution of Example 3.

[0048] (Comparative Example 1) A sintered body was produced, the crystal phase was identified, a plasma exposure test was performed, and the erosion rate was measured in the same manner as in Example 1, except that the content of ZrO2 powder in the mixture of Y2O3 powder and ZrO2 powder was adjusted to 15 mol%.

[0049] (Comparative Example 2) A sintered body was produced, the crystal phase was identified, a plasma exposure test was performed, and the erosion rate was measured in the same manner as in Example 1, except that the content of ZrO2 powder in the mixture of Y2O3 powder and ZrO2 powder was adjusted to 20 mol%.

[0050] (Comparative Example 3) A sintered body was produced, the crystal phase was identified, a plasma exposure test was performed, and the erosion rate was measured in the same manner as in Example 1, except that the content of ZrO2 powder in the mixture of Y2O3 powder and ZrO2 powder was adjusted to 30 mol%. Here, the XRD diagram used for identifying the crystal phase of the solid solution in Comparative Example 3 is shown in Fig. 5(b). It can be seen from Fig. 5(b) that not only the peaks of the regular hexahedron crystal structure of Y2O3 but also the peaks of ZrO2 are generated in the solid solution of Comparative Example 3.

[0051] (Example 4) Y2O3 powder with an average particle size of 3.3 μm and HfO2 powder with an average particle size of 0.8 μm were prepared. The two powders were dry-mixed using a planetary mill (using zirconia balls and a zirconia pot) so that the content of the HfO2 powder was 5 mol% in the resulting mixture of Y2O3 powder and HfO2 powder. The obtained mixed powder was heated in an electric furnace at 1500 °C for 10 hours and subjected to a solid solution synthesis treatment. Next, the powder after the synthesis treatment was crushed using an alumina mortar and pestle, and a sintered body (solid solution) was produced using the crushed powder with a spark plasma sintering apparatus. The identification of the crystal phase, the plasma exposure test, and the measurement of the consumption rate were carried out using the same method as in Example 1.

[0052] (Example 5) The production of the sintered body, the identification of the crystal phase, the plasma exposure test, and the measurement of the consumption rate were carried out in the same manner as in Example 4, except that the content of HfO2 in the mixture of Y2O3 powder and HfO2 powder was made 10 mol%. Here, the XRD diagram used for the identification of the crystal phase of the solid solution in Example 5 is shown in Fig. 6(a). It can be seen from Fig. 6(a) that only the peaks of the regular hexahedron crystal structure of Y2O3 occur in the solid solution of Example 5.

[0053] (Example 6) The production of the sintered body, the identification of the crystal phase, the plasma exposure test, and the measurement of the consumption rate were carried out in the same manner as in Example 4, except that the content of HfO2 in the mixture of Y2O3 powder and HfO2 powder was made 20 mol%.

[0054] (Comparative Example 4) The production of the sintered body, the identification of the crystal phase, the plasma exposure test, and the measurement of the consumption rate were carried out in the same manner as in Example 4, except that the content of HfO2 in the mixture of Y2O3 powder and HfO2 powder was made 30 mol%.

[0055] (Comparative Example 5) A sintered body was prepared, the crystal phase was identified, a plasma exposure test was conducted, and the erosion rate was confirmed in the same manner as in Example 4, except that the content of HfO2 in the mixture of Y2O3 powder and HfO2 powder was adjusted to 35 mol%. Here, the XRD pattern used for identifying the crystal phase of the solid solution in Comparative Example 5 is shown in Fig. 6(b). It can be seen from Fig. 6(b) that the solid solution in Comparative Example 5 shows not only the peaks of the regular hexahedron crystal structure of Y2O3 but also the peaks of HfO2.

[0056] (Example 7) Y2O3 powder with an average particle size of 3.3 μm and Nb2O5 powder with an average particle size of 0.66 μm were prepared. The two powders were dry-mixed using a planetary mill (using zirconia balls and a zirconia pot) so that the content of Nb2O5 powder in the resulting mixture of Y2O3 powder and Nb2O5 powder was 2 mol%. The obtained mixed powder was heated in an electric furnace at 1500 °C for 10 hours and subjected to a solid solution synthesis treatment. Next, the powder after the synthesis treatment was crushed using an alumina mortar and pestle, and a sintered body (solid solution) was prepared using the crushed powder with a spark plasma sintering apparatus. The identification of the crystal phase, the plasma exposure test, and the measurement of the erosion rate were carried out in the same manner as in Example 1.

[0057] (Example 8) A sintered body was prepared, the crystal phase was identified, a plasma exposure test was conducted, and the erosion rate was measured in the same manner as in Example 7, except that the content of Nb2O5 in the mixture of Y2O3 powder and Nb2O5 powder was adjusted to 5 mol%. Here, the XRD pattern used for identifying the crystal phase of the solid solution in Example 8 is shown in Fig. 7(a). It can be seen from Fig. 7(a) that only the peaks of the regular hexahedron crystal structure of Y2O3 are present in the solid solution of Example 8.

[0058] (Comparative Example 6) A sintered body was prepared, the crystal phase was identified, a plasma exposure test was conducted, and the erosion rate was measured in the same manner as in Example 7, except that the content of Nb2O5 in the mixture of Y2O3 powder and Nb2O5 powder was adjusted to 10 mol%.

[0059] (Comparative Example 7) The sintered body was produced, the crystal phase was identified, the plasma exposure test, and the erosion rate were measured in the same manner as in Example 7, except that the content of Nb2O5 in the mixture of Y2O3 powder and Nb2O5 powder was adjusted to 15 mol%. From FIG. 7(b) showing the XRD pattern used for identifying the crystal phase of the solid solution in Comparative Example 7, it can be seen that the solid solution in Comparative Example 7 shows not only the peaks of the regular hexahedron crystal structure of Y2O3 but also the peaks of Nb2O5.

[0060] (Comparative Example 8) The sintered body was produced, the crystal phase was identified, the plasma exposure test, and the erosion rate were measured in the same manner as in Example 7, except that the content of Nb2O5 in the mixture of Y2O3 powder and Nb2O5 powder was adjusted to 20 mol%.

[0061] (Comparative Example 9) A sintered body was produced using Y2O3 powder with an average particle size of 1 - 2 μm by a spark plasma sintering apparatus. The identification of the crystal phase, the plasma exposure test, and the measurement of the erosion rate were carried out using the same method as in Example 1.

[0062] The results of X-ray diffraction and the results of the plasma exposure test in each of the above-described examples and comparative examples are shown in Table 1 below. Here, in the X-ray diffraction results in Table 1, ○ is marked for those in which only the peaks of the regular hexahedron structure of Y2O3 were detected as a result of identifying the crystal phase using the X-ray diffraction method, and × is marked for those in which peaks of metal oxides solid-solved in Y2O3 or peaks of complex oxides, etc. were detected in addition to the peaks of the regular hexahedron structure of Y2O3. Also, the erosion rate in Table 1 is a value obtained by comparing the erosion rate of the Si wafer subjected to the plasma exposure test with the erosion rates of each of the examples and comparative examples subjected to the plasma exposure test. Taking the erosion rate of the Si wafer as 100, the erosion rates of each test piece are shown as the erosion rate.

[0063]

Table 1

[0064] From the results in Table 1, it can be seen that the erosion rates of the sintered bodies (solid solutions) of Examples 1 to 8 in which only the peaks of the regular hexahedron crystal structure of Y2O3 were detected by X-ray diffraction method are smaller than those of the sintered bodies of Comparative Examples 1 to 9 in which peaks of other metal oxides were observed. That is, it shows that by dissolving ZrO2, HfO2, or Nb2O5 in Y2O3 at a ratio within the range where the regular hexahedron crystal structure of Y2O3 is maintained, the erosion by plasma can be significantly reduced.

[0065] Next, examples of the thermal spray coating obtained using the film-forming material of the present invention will be described. (Example 9) A slurry of Y2O3-ZrO2 was prepared using a ZrO2 aqueous sol (Nissan Chemical Co., Ltd., trade name: Nano Use ZR), Y2O3 powder with an average particle size of 1.5 μm, and ion-exchanged water. The content ratio of ZrO2 in the total amount of Y2O3 and ZrO2 contained in this slurry was 10 mol%, and the content rate of the total solid content was 45 wt%. Next, an acrylic binder (Chukyo Yushi Co., Ltd., trade name: Cellna WN-405) with a content of 0.40 wt% of the total solid content was added to this slurry, and spray drying granulation was performed to obtain spherical particles with an average particle size of 36 μm. These spherical particles were heated to 1350 °C in an air atmosphere using an electric furnace to perform a debinding treatment and a uniform composition treatment, and a film-forming material composed of a solid solution was prepared. Next, a substrate made of a square aluminum alloy (A5052) with a thickness of 3 mm, a length of 20 mm, and a width of 20 mm was sandblasted and roughened, and then on its surface, an atmospheric plasma spraying apparatus (plasma spraying gun (9MB manufactured by Sulzer Metco)) was used to perform atmospheric plasma spraying at an operating voltage of 65 V, an operating current of 700 A, a primary gas (Ar) flow rate of 60 NL / min, a secondary gas (H2) flow rate of 5 NL / min, and a spraying distance of 140 mm to prepare a test piece with a thermal spray coating having a thickness of about 0.15 mm.

[0066] The sprayed surface of the test piece prepared above was polished with #800 wet emery paper, ultrasonically cleaned in pure water, then dried at 85 °C in a constant temperature bath, and then subjected to a plasma exposure test to determine the consumption rate. Here, the consumption rate was defined by the magnitude of the step difference between the masked part that was not exposed to the plasma and the part that was exposed to the plasma, measured using a laser microscope. For the test, a dry etching apparatus was used, and the sintered body was placed still on the wafer and exposed to the plasma. The plasma was generated under the following conditions. Plasma gas type and flow rate: CF4··50 sccm, O2···10 sccm, Ar···50 sccm RF output··800 W, bias··600 W

[0067] (Example 10) HfO2 powder with an average particle size of 0.8 μm and Y2O3 powder with an average particle size of 3.3 μm were weighed and mixed so that the content ratio of HfO2 in the resulting mixture was 15 mol%. Next, the mixed powder was mixed in an ethanol solvent using zirconia balls and a zirconia pot. Next, the mixed powder obtained by drying was heat-treated using an electric furnace and heated up to 1500 °C in an air stream to obtain a composite powder in which HfO2 was solid-solved in Y2O3. Next, the above composite powder was crushed, and using the obtained crushed product, a slurry with a solid content fraction of 40 wt% was prepared using ion-exchanged water as a solvent.

[0068] To the slurry obtained above, an acrylic binder (Chukyo Yushi Co., Ltd., trade name: Celna WN-405) of 0.40 wt% of the solid content was added and subjected to spray drying granulation. As a result, spherical particles with an average particle size of 31 μm were obtained. Further, these spherical particles were heated up to 1450 °C in an air atmosphere using an electric furnace to perform a debinding treatment and a uniform composition treatment to prepare a film-forming material. The method for preparing the test piece and the method for confirming the consumption rate were carried out in the same manner as in Example 9.

[0069] (Comparative Example 10) Y2O3 powder with an average particle size of 3.3 μm was dispersed in ion-exchanged water at a solid content fraction of 40% by weight to prepare a slurry. Next, 0.40% by weight of an acrylic binder (manufactured by Chukyo Yushi Co., Ltd., trade name: Cerna WN-405) was added to this slurry based on the solid content, and it was subjected to spray drying granulation to obtain granulated spherical powder with an average particle size of 33 μm. Further, this spherical particle was heated to 1450 °C in an air atmosphere using an electric furnace to perform a debinding treatment and a uniform composition treatment to prepare a film-forming material. The method for preparing the test piece and the method for confirming the consumption rate were carried out in the same manner as in Example 9.

[0070] (Comparative Example 11) Y2O3 powder with an average particle size of 3.3 μm and ZrO2 powder with an average particle size of 0.9 μm were uniformly mixed so that ZrO2 in the resulting mixture was 18 mol%, and then heated to 1450 °C in an air stream and crushed. The synthetic powder was dispersed in ion-exchanged water at a solid content fraction of 40% by weight to prepare a slurry. Next, 0.40% by weight of an acrylic binder (manufactured by Chukyo Yushi Co., Ltd., trade name: Cerna WN-405) was added to this slurry based on the solid content, and it was subjected to spray drying granulation to obtain granulated spherical powder with an average particle size of 33 μm. Further, this spherical particle was heated to 1450 °C in an air atmosphere using an electric furnace to perform a debinding treatment and a uniform composition treatment to prepare a film-forming material. The method for preparing the test piece and the method for confirming the consumption rate were carried out in the same manner as in Example 9.

[0071] The results of the plasma exposure tests in the above-described respective Examples and Comparative Examples are shown in Table 2 below. Here, the consumption rate in Table 2 is a value obtained by comparing the consumption rate of the Y2O3 thermal spray coating in Comparative Example 10 subjected to the plasma exposure test with the consumption rates of the respective Examples and Comparative Examples subjected to the plasma exposure test, and is shown with the consumption rate of the Y2O3 thermal spray coating as 100.

[0072]

Table 2

[0073] From the results in Table 2, it can be seen that the consumption rates of the thermal spray coatings of Example 9 and Example 10 are lower than the consumption rate of the thermal spray coating of Comparative Example 10. On the other hand, it can be seen that the consumption rate of the thermal spray coating of Comparative Example 11 is higher than the consumption rate of the thermal spray coating of Comparative Example 10.

Industrial Applicability

[0074] The film-forming material of the present invention is effective in a wide range of fields including members for plasma etching apparatuses that use halogen gases such as fluorine gas in semiconductor manufacturing processes.

[0075] The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2021-200979 filed on December 10, 2021 are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. ZrO ２ 、HfO ２ or Nb ２ O ５ comprising a metal oxide, Y ２ O ３ and a solid solution containing the same, wherein when the metal oxide is ZrO ２ , the content of ZrO ２ is 7 to 12 mol%, when the metal oxide is HfO ２ , the content of HfO ２ is 4 to 16 mol%, when the metal oxide is Nb ２ O ５ , the content of Nb ２ O ５ is 1 to 8 mol%, and the crystal structure of the solid solution has a regular hexahedron crystal structure of Y ２ O ３ . A film-forming material characterized by this.

2. When the metal oxide is ZrO ２ , the film-forming material according to claim 1, wherein the content of ZrO ２ is 8 to 11 mol%.

3. When the metal oxide is HfO ２ , the film-forming material according to claim 1, wherein the content of HfO ２ is 10 to 16 mol%.

4. wherein the metal oxide is Nb ２ O ５ when it is, the film-forming material according to claim 1, wherein the content of Nb ２ O ５ is 3 to 7 mol%.

5. The film-forming material according to any one of claims 1 to 4, wherein the ratio of Zr, Hf, or Nb atoms to Y atoms contained in the solid solution is within ±5% with respect to the absolute value at five randomly selected points of the solid solution contained in the film-forming material.

6. The solid solution exhibits only peaks of the regular hexahedral crystal structure of Y ２ O ３ in X-ray diffraction (XRD). The film-forming material according to any one of claims 1 to 4

7. A film-forming method by physical vapor deposition using the film-forming material according to any one of claims 1 to 4.

8. A method for manufacturing a member for a plasma etching apparatus, which forms a protective film on a substrate by the film-forming method according to claim 7.

9. A method for producing a film-forming material according to any one of claims 1 to 4, wherein ZrO ２ , HfO ２ or Nb ２ O ５ consisting of metal oxide powder and Y ２ O ３ powder, and when the metal oxide is ZrO ２ , a mixed powder having a ZrO ２ content of 7 to 12 mol% is heat-treated at 1000 to 1600 °C to form a solid solution. When the metal oxide is HfO ２ , a mixed powder having a HfO ２ content of 4 to 16 mol% is heat-treated at 1200 to 1600 °C to form a solid solution. When the metal oxide is Nb ２ O ５ , a mixed powder having a Nb ２ O ５ content of 1 to 8 mol% is heat-treated at 1200 to 1600 °C to form a solid solution, which is a method for producing a film-forming material.

10. The method for manufacturing a film-forming material according to claim 9, wherein after forming the solid solution, it is granulated into particles having an average particle size of 15 to 40 μm and heat-treated at a temperature of 1200 to 1500°C.

11. A method for manufacturing a film-forming material according to any one of claims 1 to 4, wherein ZrO ２ 、 HfO ２ or Nb ２ O ５ containing metal oxide sol, Y ２ O ３ powder, and a mixed solution containing the same as a raw material are spray-dried and granulated, and the obtained ZrO ２ fine particles, HfO ２ fine particles or Nb ２ O ５ fine particles and Y ２ O ３ A method for producing a film-forming material, characterized in that spherical particles composed of primary particles of fine particles are heat-treated at a temperature of 1000 to 1500 ° C in an oxidizing atmosphere to form a solid solution.

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