Plasma-resistant member, plasma processing device component, and plasma processing device

Abstract

The present invention is a plasma-resistant member in which a surface exposed to plasma is formed of a single-crystal yttrium aluminum garnet (YAG) {100} surface, and a plasma processing device component and a plasma processing device using the same. When a plurality of surfaces exposed to plasma are present, at least the surface most required to be plasma-resistant is formed of a single-crystal YAG {100} surface.

Description

TECHNICAL FIELD

[0001] The present application relates to a plasma-resistant member used in an environment exposed to plasma, a plasma processing device part, and a plasma processing device. BACKGROUND

[0002] Conventionally, in a semiconductor manufacturing process or the like, a thin film is formed on an object using plasma, or a device that performs etching processing on an object is used. In a plasma film forming device, a raw material gas is plasma- ized and chemically reacted to form a thin film on an object. In a plasma etching device, an etching gas is plasma- ized, and a surface of an object is chemically reacted with plasma to be gasified, thereby etching the object.

[0003] In the reaction chamber of these plasma processing devices, various plasma processing device parts such as a gas nozzle, a window, a substrate mounting part, and the like are used. As the material of these plasma processing device parts, a ceramic sintered body such as yttria, yttrium aluminum garnet (YAG), alumina, or the like is used (Patent Document 1).

[0004] If the surface of the plasma processing device part reacts with a gas or plasma having high reactivity, particles are generated from the surface. If the particles adhere to an object, it can become a cause of defects, and thus plasma resistance is required for the plasma processing device part. It is known that yttria and YAG have higher plasma resistance than alumina (Patent Documents 1 and 2).

[0005] In order to reduce defects caused by particles, a plasma-resistant member having more excellent plasma resistance is required.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT DOCUMENTS

[0008] Patent Document 1: WO2014 / 119177

[0009] Patent Document 2: Japanese Patent Application Publication No. 10-45461 SUMMARY

[0010] The present application is a plasma-resistant member in which a surface exposed to plasma is formed of a single crystal yttrium aluminum garnet (YAG) having a {100} surface, and a plasma processing device part and a plasma processing device using the plasma-resistant member.

[0011] The present application is a plasma-resistant member having a plurality of surfaces exposed to plasma, at least the surface most required to be resistant to plasma being formed of a single-crystal YAG {100} surface, a plasma processing apparatus part using the plasma-resistant member, and a plasma processing apparatus, BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a schematic view of a plasma processing apparatus of the present application.

[0013] Figure 2A is a schematic perspective view of a gas nozzle using the plasma-resistant member of the present application.

[0014] Figure 2B is Figure 2A is a cross-sectional view taken along the A1-A1 line of

[0015] Figure 3 is a schematic view of a window using the plasma-resistant member of the present application.

[0016] Figure 4A is another example of a gas nozzle using the plasma-resistant member of the present application.

[0017] Figure 4B is another example of a gas nozzle using the plasma-resistant member of the present application. DETAILED DESCRIPTION

[0018] Hereinafter, one embodiment of the present application will be described with reference to the drawings. The present application provides a plasma-resistant member excellent in plasma resistance and less likely to generate particles, a plasma processing apparatus part, and a plasma processing apparatus.

[0019] In the present specification, the plasma-resistant member is a part having corrosion resistance (difficult to be etched) to plasma of a halogen-based gas or the like.

[0020] The plasma-resistant member is used for a gas supply part such as an injector, a gas nozzle, a shower head, and the like; an internal monitoring part such as a window and the like; a substrate holding part such as an electrostatic chuck, a carrier, and the like; a protective part such as a protective tube of a thermocouple, and the like in a plasma processing apparatus such as a plasma film forming apparatus, a plasma etching apparatus, and the like.

[0021] Figure 1 is a schematic cross-sectional view of a plasma processing apparatus using the plasma-resistant member of the present application. The plasma processing apparatus 1 forms a thin film on an object 5 such as a semiconductor wafer, a glass substrate, and the like, or performs etching processing, and is an apparatus that performs modification processing of a surface of the object 5.

[0022] The plasma processing apparatus 1 has a reaction chamber 2 for processing an object 5. Inside the reaction chamber 2, there are provided a gas nozzle 4 for supplying a gas into the reaction chamber 2, and a holding portion 6 such as an electrostatic chuck having an internal electrode 7. Outside the reaction chamber 2, there are provided a gas supply pipe 3 for supplying a raw material gas to the gas nozzle 4, a coil 9 and a power source 10 for supplying electric power for generating plasma, and a bias power source 8 connected to the internal electrode 7. In addition, the reaction chamber 2 further has a window 12 for observing the inside thereof.

[0023] The object 5 is placed on the holding portion 6, a gas is supplied into the reaction chamber 2 via the gas nozzle 4, and the object 5 is processed by plasma generated by discharge of electric power supplied from the coil 9 and the power source 10.

[0024] For example, when a thin film containing silicon oxide (SiO2) is formed on the object 5, a raw material gas such as silane (SiH4) and oxygen (O2) is supplied, and when the object 5 is subjected to etching processing, an etching gas such as a halogen-based gas such as SF6, CF4, CHF3, C1F3, NF3, C3F8, C4F8, HF, Cl2, HCl, BCl3, CCl4, and the like is supplied.

[0025] Figure 2A 、 Figure 2B is a schematic view of a gas nozzle using the plasma-resistant member of the present application. Figure 2A is a perspective view, Figure 2B is Figure 2A is a sectional view taken along the A1-A1 line of Figure 2A The gas nozzle 4 is formed, for example, in a cylindrical, prismatic, or the like columnar shape, and a plurality of (four in the example shown) gas supply holes 11 for guiding the supply of a gas are provided along the axis of the gas nozzle 4. The end face 4a, the outer peripheral surface 4b, and the inner peripheral surface 4c of the gas nozzle 4 are exposed to plasma.

[0026] Figure 3 is a schematic view of a window using the plasma-resistant member of the present application. The window 12 has a first face 12a and a second face opposed to each other, and the first face 12a is exposed to plasma.

[0027] A single-crystal yttrium aluminum garnet (YAG) has a crystal structure of a cubic system, and has crystal orientations such as a {100} face and a {111} face. YAG is a material having high plasma resistance, but particularly, the {100} face is excellent in plasma resistance, which was made clear by the present inventors in the following experiments.

[0028] In order to evaluate the plasma resistance of various members, a reactive ion etching device (RIE device) was used to irradiate a test sample with a CF4 plasma, and the etching depth (etching rate) was compared. The etching depths of the alumina ceramic, the (100) single-crystal YAG, the (111) single-crystal YAG, and the yttria ceramic were 0.61 μm, 0.16 μm, 0.20 μm, and 0.13 μm, respectively. It was found that the plasma resistance of the single-crystal YAG was higher than that of the alumina ceramic and was equivalent to that of the yttria ceramic, and that the {100} face of the single-crystal YAG had excellent plasma resistance.

[0029] In addition, because the strength of the single-crystal YAG is higher than that of the yttria ceramic, the plasma-resistant member of the present application can be a member having both high strength and high corrosion resistance.

[0030] In the plasma-resistant member of the present application, the face exposed to the plasma is formed of a single-crystal YAG having a {100} face.

[0031] When the plasma-resistant member of the present application is used as the window 12, at least the first face 12a exposed to the plasma is formed of a single-crystal YAG having a {100} face.

[0032] In addition, in a part, such as the gas nozzle 4, in which a plurality of faces (in the gas nozzle 4, the end face 4a, the outer peripheral face 4b, and the inner peripheral face 4c) are exposed to the plasma, at least the face most required to have plasma corrosion resistance is formed of a single-crystal YAG having a {100} face. For example, in the example shown in FIG. 8, the end face 4a of the gas nozzle 4 is made a {100} face. In addition, as shown in FIG. 9, the cross-sectional shape of the supply hole 11 can be rectangular, and the inner peripheral face 4c can also be made a {100} face. In addition, the cross-sectional outer shape of the gas nozzle 4 can be rectangular, and the outer peripheral face 4b can be made a {100} face. Figure 2A 2B Figure 2A

[0033] In the plasma-resistant member of the present application, the face exposed to the plasma is formed of a single-crystal YAG. As described in the literature, the corrosion resistance is improved by reducing the porosity and the surface roughness of the member. The single crystal has a small and few (or no) pores, and thus has high corrosion resistance, as compared with a ceramic (polycrystal). In addition, in a polycrystal, the grain boundary is more easily etched than the grain, but in a single crystal, there is no grain boundary, and thus the corrosion resistance is high. In addition, because there is no grain boundary, the pores are small and few (or none), and thus the surface roughness is easily reduced. In addition, because there is no grain boundary, the pores are small and few (or none), and thus the generation of particles is difficult. Based on the above reasons, the single-crystal YAG has excellent corrosion resistance, and is a plasma-resistant member in which particles are less likely to be generated.

[0034] ​​​Further, the crystal plane of YAG used in the plasma-resistant member of the present application can have an offset angle of ±10° or less from the {100} plane, and particularly preferably an offset angle of ±5° or less. If the offset angle is 10° or less, plasma resistance comparable to that of the {100} plane can be expected.

[0035] Since the crystal structure of YAG is cubic, the {100} plane is four-fold symmetric, and if it is rotated 90° about an axis perpendicular to the plane, an equivalent plane appears. Therefore, in a columnar or cylindrical member such as a gas nozzle, the axial direction is the <100> direction and the end surface 4a, which is the plane most exposed to the plasma, is the {100} plane, as in the example of Figure 2A or the example of Figure 4A At least any one of the cross-sectional shape of the inner peripheral surface (e.g., the inner peripheral surface of the supply hole 11 of the gas nozzle 4, the inner peripheral surface 21 of the gas nozzle 24) or the outer peripheral surface of the member, which is perpendicular to the axis, can be rectangular, and particularly preferably square. If it is such a structure, each inner peripheral surface or each outer peripheral surface becomes an equivalent plane, and the corrosion resistance and various physical properties of each plane are equivalent, and thus it is suitable as a corrosion-resistant member. For example, deformation due to anisotropy of the thermal expansion rate is less likely to occur.

[0036] For the same reason, the axial direction of the member is the <100> direction and the end surface 4a, which is the plane most exposed to the plasma, is the {100} plane, as in the example of Figure 4B In this case, if the cross-sectional shape (external shape, internal shape, arrangement of the through hole 31) of the member (gas nozzle 34) perpendicular to the axis is four-fold symmetric, the various physical properties of the cross-section become relatively isotropic, and thus it is suitable as a corrosion-resistant member.

[0037] The plasma-resistant member having the above structure is used in the plasma processing apparatus part and the plasma processing apparatus of the present application.

[0038] The single-crystal YAG ingot can be produced, for example, by the CZ (Chochralski pulling) method. A raw material in which high-purity (e.g., 4N or more) yttrium oxide powder and aluminum oxide powder are mixed, or a polycrystalline YAG obtained by preheating the raw material, is filled into a crucible made of a high-melting-point metal such as iridium, heated to be molten, and a seed crystal is immersed in the melt and pulled up at a predetermined pulling-up speed and rotation speed, whereby a single crystal having a cylindrical straight body portion can be grown. By appropriately selecting the crystal orientation of the seed crystal, a single crystal of a desired crystal orientation and high purity (e.g., 4N or more) can be produced.

[0039] A single crystal YAG in a rod shape, a cylinder shape, or a plate shape can be produced, for example, by an EFG (Edge-defined Film-fed Growth) method. A raw material in which a high-purity (for example, 4N or more) yttrium oxide powder and a high-purity (for example, 4N or more) aluminum oxide powder are mixed, or a polycrystal YAG obtained by pre-sintering the raw material, is filled into a crucible made of a high-melting-point metal such as iridium, which is provided with a mold having a slit, and is heated to be molten. A seed crystal is immersed in the melt supplied to the upper surface of the mold through the slit, and is lifted at a predetermined lifting speed, whereby a single crystal in a rod shape, a cylinder shape, or a plate shape can be grown. By appropriately selecting the crystal orientation of the seed crystal, a single crystal of a desired crystal orientation and a high purity (for example, 4N or more) can be produced.

[0040] The grown ingot is cut into a desired length (thickness) by a wire saw, a cylindrical blade cutter, or the like, and is processed into a desired shape and surface roughness by a numerical control machine tool, a grinding device, or the like, whereby a product such as a gas nozzle can be produced.

[0041] Symbol explanation

[0042] 1: Plasma processing apparatus

[0043] 2: Reaction chamber

[0044] 3: Gas introduction pipe

[0045] 4: Gas nozzle

[0046] 4a: End surface

[0047] 4b: Outer peripheral surface

[0048] 4c: Inner peripheral surface

[0049] 5: Object

[0050] 6: Holding portion

[0051] 7: Internal electrode

[0052] 8: Bias power supply

[0053] 9: Coil

[0054] 10: Power supply

[0055] 11: Supply hole

[0056] 12: Window

[0057] 12a: First surface

Claims

1. A plasma-resistant member which is a columnar or cylindrical plasma-resistant member whose face exposed to plasma is formed of a single-crystal YAG of {100} face, the end face is formed of a single-crystal YAG of {100} face, the axial direction of the columnar or cylindrical plasma-resistant member is a <100> direction, and the shape of a cross section perpendicular to the axis of at least any one of the inner peripheral surface or the outer peripheral surface is rectangular.

2. A plasma-resistant member which is a columnar or cylindrical plasma-resistant member whose face exposed to plasma is formed of a single-crystal YAG of {100} face, the end face is formed of a single-crystal YAG of {100} face, the axial direction of the columnar or cylindrical plasma-resistant member is a <100> direction, and the shape of a cross section perpendicular to the axis is 4-fold symmetry.

3. A part for a plasma processing apparatus which uses the plasma-resistant member according to claim 1 or 2.

4. A plasma processing apparatus which uses the plasma-resistant member according to claim 1 or 2.

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