JP7223669B2 - Corrosion-resistant materials, parts for semiconductor manufacturing equipment, and semiconductor manufacturing equipment - Google Patents

Description

The present invention relates to corrosion-resistant members, parts for semiconductor manufacturing equipment, and semiconductor manufacturing equipment used in environments exposed to corrosive fluids.

2. Description of the Related Art Conventionally, in a semiconductor manufacturing process or the like, a film forming apparatus for forming a thin film on an object such as a semiconductor wafer or a glass substrate, and an etching apparatus for performing microfabrication on the object have been used. In the film forming apparatus, source gas is supplied into a reaction chamber, and a thin film is formed on an object by chemically reacting the source gas. The raw material gas may contain a highly reactive gas. In an etching apparatus, an etching gas such as a halogen-based gas is supplied into a reaction chamber, and the surface of the object is vaporized by a chemical reaction with the etching gas, thereby finely processing the object. The raw material gas and the etching gas may be plasmatized in the reaction chamber and used.

In reaction chambers of these semiconductor manufacturing apparatuses, various semiconductor manufacturing apparatus parts such as gas nozzles, windows, and substrate mounting parts are used. Ceramic sintered bodies such as yttria, yttria aluminum garnet (YAG), and alumina are used as materials for these parts for semiconductor manufacturing equipment (Patent Document 1).

When the surface of a component for semiconductor manufacturing equipment reacts with highly reactive gas or plasma, particles may be generated from the surface. If particles adhere to an object, they may cause defects, so parts for semiconductor manufacturing equipment are required to have corrosion resistance. Yttria and YAG are known to have higher corrosion resistance than alumina. It is also known that the corrosion resistance is improved by reducing the surface roughness and porosity of the corrosion-resistant member (Patent Documents 1 and 2).

In order to reduce defects caused by particles, there is a demand for corrosion-resistant members with even better corrosion resistance.

WO2014/119177 JP-A-10-45461

An object of the present disclosure is to provide a corrosion-resistant member, a component for a semiconductor manufacturing apparatus, and a semiconductor manufacturing apparatus that are excellent in corrosion resistance and generate less particles.

The present disclosure relates to a corrosion-resistant member made of single-crystal YAG, a component for a semiconductor manufacturing apparatus, and a semiconductor manufacturing apparatus using the corrosion-resistant member.

According to the present disclosure, it is possible to provide a corrosion-resistant member, a component for a semiconductor manufacturing apparatus, and a semiconductor manufacturing apparatus that are excellent in corrosion resistance and generate less particles.

1 is a schematic cross-sectional view of a plasma processing apparatus; FIG. 1 is a schematic diagram of a gas nozzle; FIG. It is a cross-sectional shape of a corrosion-resistant member.

Embodiments of the present invention will be described below with reference to the drawings.

In this specification, a corrosion-resistant member is a component that has corrosion resistance against highly reactive corrosive fluids such as plasma, halogen-based gas, acidic liquids, and alkaline liquids.

Corrosion-resistant members are used in semiconductor manufacturing processes such as film deposition equipment (CVD equipment, etc.), etching equipment (RIE equipment, etc.), plasma processing equipment, semiconductor manufacturing equipment such as various reactors, and corrosive materials such as halogen-based gases. It is used in excimer lasers that use strong gases and cleaning equipment that uses high-temperature corrosive liquids. For example, in semiconductor manufacturing equipment, gas supply parts such as injectors, gas nozzles and shower heads, internal inspection parts such as windows, substrate holding parts such as electrostatic chucks and carrier plates, protective parts such as thermocouple protective tubes, etc. used for

FIG. 1 is a schematic cross-sectional view of a plasma processing apparatus, which is an example of a semiconductor manufacturing apparatus using the corrosion-resistant member of the present disclosure. The plasma processing apparatus 1 is an apparatus for forming a thin film on an object 5 such as a semiconductor wafer or a glass substrate, performing an etching process, or modifying the surface of the object 5 . A plasma processing apparatus 1 comprises a reaction chamber 2 for processing an object 5 . Inside the reaction chamber 2, there are provided a gas nozzle 4 for supplying gas into the reaction chamber 2 and a holder 6 such as an electrostatic chuck provided with an internal electrode 7. As shown in FIG. Outside the reaction chamber 2, there are a gas supply pipe 3 for supplying raw material gas to the gas nozzle 4, a coil 9 and a power supply 10 for supplying power for generating plasma, and a bias power supply 8 connected to the internal electrode 7. Prepare.

An object 5 is placed on the holding part 6, gas is supplied into the reaction chamber 2 through the gas nozzle 4, and plasma is generated by electric discharge from the coil 9 and the power supply 10, and the object 5 is processed. be.

For example, when forming a thin film made of silicon oxide (SiO ₂ ) on the object 5, source gases such as silane (SiH ₄ ) and oxygen (O ₂ ) are supplied, and when the object 5 is etched, _{, SF6, CF4, CHF3, ClF3, NF3, C3F8, C4F8 , HF , Cl2 , HCl , BCl3 , and CCl4} . be.

FIG. 2 is a schematic diagram of a gas nozzle, which is an example of a component for semiconductor manufacturing equipment using the corrosion-resistant member of the present disclosure. (a) is a perspective view, and (b) is a cross-sectional view taken along line A1-A1 of (a). The gas nozzle 4 has a tubular supply hole 11 for guiding gas. The gas nozzle 4 is formed, for example, in a cylindrical shape, and a plurality of supply holes 11 (four in the example shown in FIG. 2) are provided along the axis of the gas nozzle 4 on the circumference.

The corrosion resistant member of the present disclosure consists of single crystal yttria aluminum garnet (YAG). A component for a semiconductor manufacturing apparatus and a semiconductor manufacturing apparatus according to the present disclosure use a corrosion-resistant member made of single-crystal YAG.

In order to evaluate the corrosion resistance of various members, a reactive ion etching device (RIE device) was used to irradiate the sample with CF ₄ plasma, and the etching depth (etching rate) was compared. The etching depths of alumina ceramics, sapphire (single crystal alumina), single crystal YAG, and yttria ceramics are 0.61 μm, 0.56 μm, 0.16 μm, and 0.13 μm, respectively. , alumina ceramics, sapphire (single crystal alumina), and comparable to yttria ceramics.

As described in the prior art, YAG and yttria have higher corrosion resistance than alumina. Corrosion resistance is improved by reducing porosity and surface roughness. Single crystals have smaller and fewer pores (or no pores at all) than ceramics (polycrystals), and therefore have high corrosion resistance. Also, in polycrystals, the grain boundaries have poorer crystallinity than the insides of crystals and are easily etched, but since single crystals do not have grain boundaries, they have high corrosion resistance. In addition, since there are no crystal grain boundaries and the pores are small (few), the surface roughness can be easily reduced. For the reasons described above, single-crystal YAG serves as a corrosion-resistant member with excellent corrosion resistance.

Furthermore, YAG ceramics deteriorates due to progress of sintering when the environmental temperature of use rises close to the sintering temperature (about 50 to 80% of the melting point (° C.) at the time of manufacturing, whereas single crystal YAG It is stable up to near the melting point and has excellent heat resistance. YAG has a melting point of about 1970°C, and deterioration is reduced even in a high temperature environment of 1600°C to 1900°C.

In addition, YAG is a softer material than alumina, and single-crystal YAG members have excellent processing accuracy compared to sapphire members, and parts that require processing accuracy, such as laser windows and lenses. It is suitable as a material for thin film parts such as parts and diaphragms for pressure sensors. In addition, since YAG has a lower melting point than yttria, single-crystal YAG is superior to single-crystal yttria in terms of productivity, and production costs can be reduced.

Since the crystal structure of YAG is a cubic system, the {100} plane has four-fold symmetry, and an equivalent plane appears when rotated 90° about an axis perpendicular to the plane. Therefore, a columnar or cylindrical member such as the gas nozzle 4 has an axial direction in the <100> direction, and as shown in FIG. surface) or the outer peripheral surface, the shape of the cross section perpendicular to the axis is rectangular, particularly preferably square, each inner peripheral surface or each outer peripheral surface is an equivalent surface, and each surface It is suitable as a corrosion-resistant member because it has the same corrosion resistance and various physical properties. For example, deformation due to the anisotropy of the coefficient of thermal expansion is less likely to occur. Similarly, the axial direction of the member is the <100> direction, and as shown in FIG. If it is symmetrical, various physical properties in the cross section will be relatively isotropic, so it is suitable as a corrosion-resistant member.

Also, since the {111} plane has three-fold symmetry, an equivalent plane appears when rotated 120° about an axis perpendicular to the plane. Therefore, in a columnar or cylindrical member such as the gas nozzle 4, the axial direction is the <111> direction, and as shown in FIG. If the cross-sectional shape is an equilateral triangle, each inner peripheral surface or each outer peripheral surface becomes an equivalent surface, and each surface has the same corrosion resistance and various physical properties, and is suitable as a corrosion-resistant member. For example, deformation due to the anisotropy of the coefficient of thermal expansion is less likely to occur. Similarly, the axial direction of the member is the <111> direction, and as shown in FIG. If so, various physical properties in a cross section are relatively isotropic, and therefore, it is suitable as a corrosion-resistant member.

An ingot of single-crystal YAG can be produced, for example, using the CZ (Czochralski) method. A raw material obtained by mixing high-purity (for example, 4N or higher) yttria powder and alumina powder, or polycrystalline YAG obtained by calcining the raw material, is filled in a crucible made of a high-melting-point metal such as iridium, and heated. After the seed crystal is melted and immersed in the melt, it is pulled up at a predetermined pulling speed and rotational speed to grow a single crystal having a cylindrical straight body. By appropriately selecting the crystal orientation of the seed crystal, a high-purity (for example, 4N or higher) single crystal having a desired crystal orientation can be produced.

Rod-shaped, cylindrical, and plate-shaped single-crystal YAG can be produced, for example, using an EFG (Edge-defined Film-fed Growth) method. A raw material obtained by mixing high-purity (for example, 4N or higher) yttria powder and alumina powder, or polycrystalline YAG obtained by calcining the raw material, is placed in a mold having a slit and is made of a high melting point metal such as iridium. The seed crystal is filled in a crucible, melted by heating, and immersed in the melt supplied to the upper surface of the mold through a slit. A single crystal can be grown. By appropriately selecting the crystal orientation of the seed crystal, a high-purity (for example, 4N or higher) single crystal having a desired crystal orientation can be produced.

The grown ingot is cut to the desired length (thickness) using various cutting machines such as wire saws and peripheral cutting machines, and the desired shape and surface roughness are obtained using various processing equipment such as machining centers and polishing machines. Products such as gas nozzles can be manufactured by processing to

Reference Signs List 1: Plasma processing apparatus 2: Reaction chamber 3: Gas introduction pipe 4: Gas nozzle 5: Object 6: Holding part 7: Internal electrode 8: Bias power supply 9: Coil 10: Power supply 11: Supply hole

Claims (7)

A columnar or cylindrical corrosion-resistant member made of single-crystal YAG, having a <100> axial direction, and a rectangular cross-sectional shape perpendicular to the axis of at least one of the inner peripheral surface and the outer peripheral surface. Corrosion resistant material. A columnar or cylindrical corrosion-resistant member made of single-crystal YAG, the corrosion-resistant member having an axial direction in the <100> direction and a cross-sectional shape perpendicular to the axis having four-fold symmetry. A columnar or cylindrical corrosion-resistant member made of single-crystal YAG, having an axial direction in the <111> direction, and an equilateral triangular cross-sectional shape of at least one of the inner peripheral surface and the outer peripheral surface perpendicular to the axis. A certain corrosion resistant member. What is claimed is: 1. A columnar or tubular corrosion-resistant member made of single-crystal YAG, the axial direction of which is in the <111> direction, and the cross-sectional shape perpendicular to the axis is three-fold symmetrical. The corrosion resistant member according to any one of claims 1 to 4 , which is used in a high temperature environment of 1600°C or higher. A component for a semiconductor manufacturing apparatus using the corrosion-resistant member according to any one of claims 1 to 5 . A semiconductor manufacturing apparatus using the corrosion-resistant member according to any one of claims 1 to 5 .

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