Sintered Body and Member for Semiconductor Manufacturing Equipment

Abstract

To provide a sintered body of yttrium oxyfluoride excellent in impact resistance.SOLUTION: The sintered body comprises yttrium oxyfluoride. At least a surface of the sintered body has microcracks.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sintered body and a member for a semiconductor manufacturing apparatus.

Background Art

[0002] In each process in semiconductor manufacturing, particularly in dry etching, plasma etching, and cleaning processes, fluorine-based corrosive gases, chlorine-based corrosive gases, and plasmas using these are used.

[0003] When using these corrosive gases and plasmas, the components of the semiconductor manufacturing apparatus may be corroded, and fine particles (particles) detached from the surface of the above components may adhere to the surface of the semiconductor, easily causing product defects. Therefore, for the components of the semiconductor manufacturing apparatus, ceramics with high corrosion resistance to halogen-based plasmas need to be used as the bulk material.

[0004] As such a bulk material, a sintered body made of yttrium oxyfluoride (yttrium oxyfluoride) has been proposed (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the sintered body described in Patent Document 1 is brittle against thermal shock and physical shock, and there is still room for improvement in impact resistance as a structural member of a semiconductor manufacturing apparatus.

[0007] In view of the above problems, an object of the present invention is to provide a sintered body of yttrium oxyfluoride having excellent impact resistance.

Means for Solving the Problem

[0008] The sintered body of the present invention for solving the above problems is a sintered body containing yttrium oxyfluoride, characterized in that it has microcracks on at least the surface of the sintered body.

[0009] When a physical shock or a thermal shock is applied to the sintered body, cracks progress from the impact point, and chipping and cracking occur in the sintered body. However, if microcracks are formed in the sintered body, the energy of the shock is absorbed by the microcracks, and the progress of the cracks generated from the impact point stops. For this reason, fatal chipping and cracking do not occur in the sintered body, and as a result, the impact resistance of the sintered body is improved.

[0010] It is desirable that the width of the microcracks is 10 nm to 300 nm. This is because it is easy to stop the cracks progressing from the impact point.

[0011] It is desirable that the length of the microcracks is 0.1 μm to 20 μm. This is because it is easy to stop the cracks progressing from the impact point.

[0012] In the present invention, as shown in the photographs of FIGS. 1 and 3, a plurality of microcracks are formed on at least the surface of the sintered body containing yttrium oxyfluoride. The microcracks have branched portions extending from branch points, and it is desirable that the plurality of microcracks are connected to each other via the branched portions. In such a structure, a network structure of microcracks is formed on the surface, and the progress of cracks can be more reliably suppressed.

[0013] In the sintered body, particles made of yttrium fluoride are dispersed in the matrix of yttrium oxyfluoride, and the progress of the microcracks may occur in the matrix of yttrium oxyfluoride and stop at the boundary between the matrix of yttrium oxyfluoride and the particles made of yttrium fluoride. This is because microcracks and particles composed of yttrium fluoride can more reliably stop the cracks propagating from the impact point.

[0014] Hereinafter, in this specification, particles composed of yttrium fluoride are simply referred to as yttrium fluoride particles or YF 3 particles.

[0015] In this specification, yttrium fluoride particles can be specified as follows. Cut the sintered body, observe its cross-section with an electron microscope (magnification 3000 times), and use a wavelength-dispersive fluorescent X-ray analyzer to map yttrium, oxygen, and fluorine. Particles with a relatively lower oxygen content and a relatively higher fluorine content compared to the matrix region are specified as yttrium fluoride particles.

[0016] Also, the cross-sectional photograph taken with the electron microscope is binarized (if the sintered body further contains voids, multi-valued processing such as ternarization is performed), and the average circle equivalent diameter D of a plurality of yttrium fluoride particles dispersed in the matrix can be calculated using image processing software (ImageJ).

[0017] The average circle equivalent diameter D is measured as follows. (1) For a certain yttrium fluoride particle A, the area of the yttrium fluoride particle A is calculated and measured using image processing software (ImageJ), and the diameter of a perfect circle having the same area as the area is calculated as the circle equivalent diameter of the yttrium fluoride particle A. (2) Next, for all the yttrium fluoride particles present on the screen, the circle equivalent diameter of each yttrium fluoride particle is calculated and obtained in the same manner as for the yttrium fluoride particle A, and the average value of these circle equivalent diameters is measured as the average circle equivalent diameter D.

[0018] In the sintered body of the present invention, it is desirable that the average circle equivalent diameter D of the particles composed of yttrium fluoride is 0.1 to 5.0 μm. This is because local deformation is likely to occur around the yttrium fluoride particles. The sintered body of the present invention has voids, and it is desirable that the porosity in the cross-section of the sintered body is 1% or less. This is because the impact resistance of the sintered body can be improved.

[0019] The porosity in the cross-section of the sintered body is measured by binarizing an electron micrograph of the cross-section of the sintered body (for example, it can be binarized into three values with the matrix of yttrium oxyfluoride, particles composed of yttrium fluoride, and voids being different from each other), and calculating the ratio of the total area of the voids to the total area of the image.

[0020] In addition, the member for a semiconductor manufacturing apparatus of the present invention includes the sintered body of yttrium oxyfluoride. The sintered body of yttrium oxyfluoride has high corrosion resistance against halogen and oxygen plasma. Therefore, a member for a semiconductor manufacturing apparatus excellent in corrosion resistance and impact resistance can be provided.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0022] (Sintered body of yttrium oxyfluoride) The sintered body of yttrium oxyfluoride of the present invention is preferably a single phase of yttrium oxyfluoride or a multi-phase in which particles composed of yttrium fluoride are dispersed in a matrix of yttrium oxyfluoride. As yttrium oxyfluoride, Y 5 O 4 F 7 is desirable, and as yttrium fluoride, YF 3 is desirable.

[0023] Figure 1 is an electron micrograph of the surface of a yttrium oxyfluoride sintered body according to Example 1. The yttrium oxyfluoride sintered body shown in Figure 1 is a sintered body of a single phase of Y 5 O 4 F 7 . Note that the black dots visible in Figure 1 are pores.

[0024] Figure 1 is an electron micrograph of the surface of a sintered body of a single phase of Y 5 O 4 F 7 magnified 3000 times. Microcracks with a width of 10 to 300 nm and a length of 1 to 20 μm are confirmed in the single phase of Y 5 O 4 F 7 . The microcrack has a branch point in one microcrack, and a plurality of microcracks extend in a dendritic shape from the branch point to form a branch portion. There are a plurality of microcracks having such branched branch portions, and the branch portions are connected to each other to form a network structure.

[0025] When a crack propagates from an impact point, the stress at the crack tip is released by the network structure of this microcrack, and the propagation of the crack stops. Therefore, by introducing microcracks at least on the surface of the sintered body, the resistance of the sintered body to physical shock and thermal shock is improved. By the way, the length of the microcrack is defined as the straight-line distance between the ends of the microcrack. When the microcrack branches and has a branch portion, the length of the microcrack is defined by the straight-line distance between the end of the microcrack and the branch point closest to the end, and the respective straight-line distances between the closest branch points.

[0026] FIG. 2 is a schematic diagram for explaining the definition of the length of a microcrack. For example, as shown in FIG. 2, when there are ends A1 to A4 and branch points B1 and B2, the respective straight-line distances of A1 - B1, A2 - B1, A3 - B2, A4 - B2, and B1 - B2 are the lengths of the microcrack. Note that A1 - B1, A2 - B1, A4 - B2, and A3 - B2 extending from the branch points B1 and B2 can be respectively regarded as branch portions.

[0027] FIG. 3 is an electron micrograph of the surface of a yttrium oxyfluoride sintered body according to Example 2. The yttrium oxyfluoride sintered body shown in FIG. 3 is a sintered body in which Y 5 O 4 F 7 particles are dispersed in the matrix of. 3 It is a sintered body in which particles are dispersed. This sintered body is composed of a matrix of yttrium oxyfluoride (the region that appears white) and yttrium fluoride particles (the region that appears gray) dispersed in the matrix. It is confirmed that the crack propagates in the matrix of yttrium oxyfluoride and the propagation stops at the boundary between the matrix and the yttrium fluoride particles.

[0028] FIG. 3 is an electron micrograph obtained by magnifying 3000 times the surface of a sintered body in which Y 5 O 4 F 7 particles are dispersed in the matrix of. In the matrix of Y 3 microcracks with a width of 10 to 200 nm and a length of 0.1 to 10 μm are confirmed. The microcracks occur in the matrix of Y 5 O 4 F 7 and the propagation of the microcracks is 5 O 4 F 7 in the matrix of, and the propagation of the microcracks is5 O 4 F 7 in the matrix of and YF 3 stops at the boundary of the particles. The microcrack has a branch point in one microcrack, and a plurality of microcracks extend from the branch point in a branched manner to form a branch portion. There are a plurality of microcracks having such branched branch portions, and the branch portions can be connected to each other to form a network structure. When a crack propagates from the impact point, due to the network structure of the microcracks or YF 3 the stress at the crack tip is released by the particles, and the propagation of the crack stops. Therefore, Y 5 O 4 F 7 introduce microcracks into the matrix of, and further Y 5 O 4 F 7 in the matrix of YF 3 By dispersing the particles, the resistance of the sintered body to physical and thermal shocks is improved.

[0029] In the sintered body of the present invention, the YF 3 The content ratio of the particles can be obtained by binarizing an electron micrograph of the cross section of the sintered body and calculating the total area of the YF 3 particles from the binarized image. The total area of the YF 3 particles is preferably 0.1 to 49% with respect to the total area of this image. In the present invention, the YF 3 particles are not necessarily essential and may not be confirmed on the image of the electron micrograph. YF 3 When the occupied area of the particles is 0.1% or more, deformation hardly occurs around the YF 3 particles, and when the occupied area of the YF 3 particles is 49% or less, deformation hardly occurs around the YF 3 particles, which is because the impact resistance of the sintered body decreases.

[0030] In the sintered body of yttrium oxyfluoride of the present invention, YF 3It is desirable that the average equivalent circle diameter D of the particles be 0.1 to 5.0 μm. YF 3 This is because local deformation is likely to occur around the particles.

[0031] In the sintered body of the present invention, voids are present, and it is desirable that the porosity of the voids in the cross-section of the sintered body be 1% or less. This is because the impact resistance can be improved.

[0032] (Method for manufacturing a sintered body of yttrium oxyfluoride) The sintered body of yttrium oxyfluoride of the present invention can be manufactured by the following manufacturing method. In the present invention, Y 5 O 4 F 7 and YF 3 may be used in combination, or Y 2 O 3 and YF 3 may be combined. By combining the raw materials as described above, yttrium oxyfluoride in a single phase or a plurality of phases composed of yttrium oxyfluoride and YF 5 O 4 F 7 can be obtained. 5 O 4 F 7 and YF 3

[0033] In the powder of the raw material composition, when combining Y 5 O 4 F 7 3 and YF 5 4 7 O 3 F 5 and YF 4 7 3 O 2 F 3 :YF 3 = 100:0.1 to 49 is preferable.

[0034] Also, when combining Y 2 O 3 and YF 3 in terms of molar ratio, Y 2O 3 : YF 3 = 100: 175 to 300 is preferable. The composition after the firing reaction is Y in molar ratio 5 O 4 F 7 : YF 3 = 100: 0 so that Y 2 O 3 and YF 3 By determining the molar ratio of, Y 5 O 4 F 7 Single-phase yttrium oxyfluoride can be obtained. Also, the composition after the firing reaction is Y in molar ratio 5 O 4 F 7 : YF 3 = 100: (a number exceeding 0) so that Y 2 O 3 and YF 3 By determining the molar ratio of, Y 5 O 4 F 7 and YF 3 A sintered body having a plurality of phases composed of can be obtained.

[0035] Also, in the raw material composition, in addition to the above-mentioned Y 5 O 4 F 7 , Y 2 O 3 , and fluorides such as YF 3 Additives such as an organic binder, a lubricant, a dispersion medium liquid, and a molding aid may be appropriately added. The organic binder is not particularly limited, and examples thereof include polyacrylonitrile (PAN), acrylic resin, phenol resin, epoxy resin, imide resin, furan resin, and the like. The lubricant is not particularly limited, and examples thereof include polyoxyalkylene compounds such as polyoxyethylene alkyl ether and polyoxypropylene alkyl ether.

[0036] The dispersion medium liquid is not particularly limited, and examples thereof include water, organic solvents such as benzene, and alcohols such as methanol. The shaping aid is not particularly limited, and examples thereof include ethylene glycol, dextrin, fatty acids, fatty acid soaps, polyalcohols, and the like.

[0037] The particle size (average particle diameter) of the powder obtained by granulating the raw material composition is preferably, for example, 10 to 200 μm.

[0038] The process of manufacturing the sintered body of yttrium oxyfluoride will be described. The powder of the above-described raw material composition is preliminarily formed into a predetermined shape to produce a preform. The method of preliminary forming is not particularly limited, and for example, die pressing, CIP forming, etc. can be applied.

[0039] By degreasing the obtained formed body, firing it to bond the particles together and sintering, the sintered body of yttrium oxyfluoride of the present invention can be obtained. The sintering temperature and atmosphere are not particularly limited, but the atmosphere is preferably an inert atmosphere such as argon, and the sintering temperature is preferably 800 to 1100 °C. Also, the pressure during sintering may be normal pressure, or a hot isostatic pressing method (HIP) in which particles are sintered while pressurizing the formed body, a spark plasma sintering method (SPS) in which particles are sintered by mechanical pressure and pulsed electric current heating, etc. may be adopted.

[0040] Microcracks are introduced into at least the surface of the sintered body of yttrium oxyfluoride obtained in the above process. The introduction of microcracks can be performed by irradiating an electron beam under high vacuum. It is presumed that the irradiation with the electron beam causes the loss of fluorine and oxygen atoms from the surface of the sintered body and the generation of cracks. The irradiation intensity of the electron beam is desirably 20 to 200 μA in terms of current value and 10 to 25 kV in voltage. Also, the irradiation time is desirably 10 to 60 minutes. The atmospheric pressure is 0.01×10 -4 ~100×10 -4 Pa, and the irradiation intensity of the electron beam is desirably 100 to 10000 mW.

[0041] The member for a semiconductor manufacturing apparatus of the present invention is characterized by comprising a sintered body of yttrium oxyfluoride having the above-described microcracks. The sintered body of yttrium oxyfluoride is Y 5 O 4 F 7 single-phase, or Y 5 O 4 F 7 and YF 3 and is composed of a plurality of phases, and thus has strong corrosion resistance against halogen and oxygen plasmas.

[0042] In the member for a semiconductor manufacturing apparatus of the present invention, microcracks are formed at least on the surface of the sintered body of yttrium oxyfluoride. The microcracks are such that a plurality of microcracks branch off from one microcrack, and a plurality of such branched microcracks exist to form a network structure. When a crack propagates from an impact point, the stress at the crack tip is released by the network structure of the microcracks or by YF 3 particles, and the propagation of the crack stops. Therefore, by introducing microcracks at least on the surface of the sintered body, the resistance of the sintered body to physical and thermal shocks can be improved, and a member for a semiconductor manufacturing apparatus excellent in impact resistance can be provided.

[0043] Further, according to the member for a semiconductor manufacturing apparatus of the present invention, as the member for a semiconductor manufacturing apparatus, a sintered body of yttrium oxyfluoride is used, and the main component is Y 5 O 4 F 7 or the main component is Y 5 O 4 F 7 and YF 3 and thus is hardly corroded by halogen-based plasmas, has excellent resistance, and can be used over a long period of time.

[0044] The member for a semiconductor manufacturing apparatus of the specific present invention is not particularly limited, and examples thereof include a mounting table for a semiconductor member such as a wafer, an electrostatic chuck, a gas supply unit, a coolant supply unit, a transfer arm, a chamber inner wall member, an upper electrode, a shower plate, a focus ring, an edge plate, and the like.

Example

[0045] Hereinafter, examples specifically disclosing the present invention will be shown. It should be noted that the present invention is not limited only to the following examples.

[0046] (Example 1) Y 2 O 3 was 46.9 parts by weight, and YF 3 was 53.1 parts by weight (that is, the composition after the firing reaction was Y 5 O 4 F 7 : YF 3 = 100:0). 3.0 parts by weight of an acrylic resin was used as an organic binder, and 40 parts by weight of an alcohol-based solvent was used as a dispersion medium liquid. After mixing, it was dried at 70 ° C using a spray dryer and granulated to prepare a granular raw material composition. Regarding the obtained granular granulated particles, particles having a particle diameter of 80 μm or more were cut (removed) for particle size adjustment. The alcohol-based solvent was 86% by weight of ethanol and 14% by weight of isopropyl alcohol. In spray drying, the granulated particles had moisture without being completely dried. It is considered that isopropyl alcohol, whose boiling point is higher than the temperature of spray drying, remains.

[0047] Next, these granulated particles were filled into a mold of φ25 mm, uniaxially formed at 6 MPa to adjust the overall shape, and then further packed into a rubber bag and CIP formed at 200 MPa.

[0048] The above-formed body was degreased at 600 ° C for 2 hours in the atmosphere, and then fired at 950 ° C for 2 hours in an argon atmosphere to obtain a sintered body of yttrium oxyfluoride. The obtained sintered body of yttrium oxyfluoride was in the form of a plate with a diameter of φ19 mm and a thickness of 3 mm.

[0049] An electron beam was irradiated on this sintered body under the following conditions to introduce microcracks. (Electron beam irradiation conditions) Apparatus: JXA-8500F manufactured by JEOL Ltd. Acceleration voltage: 15.0 kV Irradiation current: 100 μA Atmospheric pressure: 6×10 -4 Pa Irradiation intensity of electron beam: 1500 mW Irradiation time of electron beam: 30 minutes

[0050] (Example 2) Y 2 O 3 was 36.3 parts by weight, YF 3 was 63.7 parts by weight (that is, the composition after the firing reaction was, in molar ratio, Y 5 O 4 F 7 :YF 3 =100:35), 3.0 parts by weight of an acrylic resin as an organic binder, and 40 parts by weight of an alcohol-based solvent as a dispersion medium solution were mixed, and then dried and granulated at 70 °C using a spray dryer to prepare a granular raw material composition. For the obtained granular granulated particles, the particles with a particle diameter of 80 μm or more were cut (removed) for particle size adjustment.

[0051] Next, these granulated particles were filled into a mold with a diameter of φ25 mm, uniaxially formed at 6 MPa to adjust the overall shape, and then further packed into a rubber bag and CIP formed at 200 MPa.

[0052] The above-formed body was degreased at 600 °C for 2 hours in the air, and then fired at 950 °C for 2 hours in an argon atmosphere to obtain a sintered body of yttrium oxyfluoride. The obtained sintered body of yttrium oxyfluoride was in the form of a plate with a diameter of φ19 mm and a thickness of 3 mm. An electron beam was irradiated on this sintered body under the following conditions to introduce microcracks.

[0053] Apparatus: JXA-8500F manufactured by JEOL Ltd. Accelerating voltage: 15.0 kV Irradiation current: 100 μA Atmospheric pressure: 6×10 -4 Pa Irradiation intensity of electron beam: 1500 mW Irradiation time of electron beam: 30 minutes

[0054] For the sintered compacts obtained in Examples 1 and 2, electron micrographs were taken under the following conditions. Figure 1 is an electron micrograph of the surface of the yttrium oxyfluoride sintered compact according to Example 1, and Figure 3 is an electron micrograph of the surface of the yttrium oxyfluoride sintered compact according to Example 2. The imaging conditions of the electron microscope are as follows. Equipment: S-4800 manufactured by Hitachi High-Tech Corporation Accelerating voltage: 15 kV Magnification: 3000 times

[0055] Also, for the cross-section of the sintered compact obtained in Example 2, elemental mapping of yttrium, fluorine, and oxygen was performed using a wavelength-dispersive fluorescent X-ray analyzer. Figure 4 is an electron micrograph of the cross-section of the sintered compact according to Example 2 and an image obtained by imaging the elemental mapping images of fluorine (F), oxygen (O), and yttrium (Y) for the cross-section using a wavelength-dispersive fluorescent X-ray analyzer. As can be understood from Figure 4, in the cross-section of the sintered compact, a state where dark gray particles are dispersed in a matrix that appears white (light gray) in the electron microscope image is confirmed. In the elemental mapping image, since O is not present in the particles that appear dark gray and Y and F are confirmed, this dark gray particle region is determined to be YF 3 judged.

[0056] The elemental mapping conditions by the wavelength-dispersive fluorescent X-ray analyzer are as follows. Equipment: JXA-8500F manufactured by JEOL Ltd. Accelerating voltage: 15.0 kV Irradiation current: 2.695×10 -8 A Magnification: 3000 times Time: 5 ms Size: X: 0.1303 μm Y: 0.1303 μm

[0057] Furthermore, powder X-ray diffraction (XRD) was performed on the sintered compacts obtained in Examples 1 and 2 under the following conditions to obtain powder X-ray diffraction charts. In any of the charts, the crystal structures of Y 5 O 4 F 7 were confirmed. FIG. 5 is a powder X-ray diffraction chart of the sintered compact according to Example 1, and FIG. 6 is a powder X-ray diffraction chart of the sintered compact according to Example 2. In FIGS. 5 and 6, the identification of the crystal structure of Y 5 O 4 F 7 was performed using JCPDS card number 01-080-1124.

[0058] The measurement conditions for powder X-ray diffraction are as follows. Apparatus: SmartLab manufactured by Rigaku Corporation Voltage: 40 kV, Current: 20 mA X-ray source: CuKα Scanning range: 2θ = 10 to 70° Scanning speed: 10° / min

[0059] As shown in FIGS. 1 and 2, microcracks were formed on the surfaces of the sintered compacts obtained in Examples 1 and 2. When microcracks are formed on the surface of the sintered compact, the impact resistance of the sintered compact is improved.

Claims

1. A sintered body containing yttrium oxyfluoride, wherein at least the surface of the sintered body has microcracks, the width of the microcracks is 10 nm to 300 nm, the length of the microcracks is 0.1 µm to 20 µm, a plurality of the microcracks are formed on at least the surface of the sintered body, the microcracks have branched portions extending from branch points, and the plurality of microcracks are connected to each other through the branched portions. The sintered body is characterized by this.

2. Particles made of yttrium fluoride are dispersed in a matrix of yttrium oxyfluoride, the propagation of the microcracks occurs in the matrix of yttrium oxyfluoride, and stops at the boundary between the matrix of yttrium oxyfluoride and the particles made of yttrium fluoride. The sintered body according to Claim 1.

3. A member for a semiconductor manufacturing apparatus, comprising the sintered body according to Claim 1 or 2.

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