JP2007109828A - Plasma resistant member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma resistant member with large mechanical strength in order to suppress and reduce the occurrence of particle release from the plasma resistant member. <P>SOLUTION: In the plasma resistant member needed to be plasma resistant; a plasma resistant structure is formed on the surface side thereof exposed at least to plasma, and takes a yttrium oxide polycrystalline structure as a chief component on an interface of crystals of which there is substantially inexistence of glassy grain boundary layer. A crystal structure of the yttrium oxide polycrystalline structure is made a mixture of cubic and monoclinic. Consequently, hardness of the structure consisted of the yttrium oxide polycrystalline structure is increased to suppress and reduce the particle release even it is exposed to a plasma atmosphere. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma-resistant member having plasma resistance, and more particularly to a plasma-resistant member having suitable plasma resistance in a halogen-based corrosive gas atmosphere.

Conventionally, a member for a semiconductor manufacturing apparatus that requires plasma resistance uses a high-purity alumina sintered body or a yttrium oxide sprayed film (see, for example, Patent Document 1).
However, there are pores and grain boundary layers of several to several tens of microns or more in the sintered body and sprayed film. When exposed to a plasma atmosphere, corrosion proceeds from the pores and grain boundary layers, and the size of the pores Increases and cracks occur on the surface. The degranulation accompanying the progress of corrosion scatters within the semiconductor manufacturing equipment, contaminates the semiconductor device, impairs the performance and reliability of the semiconductor, and scrapes the surface of the plasma resistant member itself, causing further degranulation. There was a problem that.

A technique is known in which the surface roughness Ra of the yttrium oxide film produced by the aerosol deposition method is made smaller than the surface roughness Ra of the yttrium oxide film produced by the thermal spraying method to reduce the number of particles (patent) Reference 2).
However, if the mechanical strength of the yttrium oxide film is not sufficiently ensured, there is a problem that the film surface is scraped by flying particles.

JP 2002-252209 A (2nd page) JP 2005-158933 A

  The present invention has been made to solve the above problems, and an object of the present invention is to suppress and reduce the occurrence of degranulation from the plasma-resistant member.

  In order to achieve the above object, according to the present invention, a plasma-resistant structure is formed at least on the surface exposed to plasma in the plasma-resistant member, and the plasma-resistant structure is mainly composed of a yttrium oxide polycrystal. The structure is a structure in which a glassy grain boundary layer does not substantially exist at the interface between the crystals of the polycrystal, and the crystal structure of the yttrium oxide polycrystal is cubic and cubic. By mixing with monoclinic system, the structure of the yttrium oxide polycrystal is increased in hardness, and it is possible to suppress and reduce degranulation even when exposed to a plasma atmosphere.

  Further, according to a preferred embodiment of the present invention, in the plasma-resistant member, the anchor portion into which a part of the yttrium oxide polycrystal body bites is formed and directly joined, whereby the base material and the yttrium oxide polycrystal body are formed. Adhesion strength with a structure made from the above has increased, and it has become possible to suppress and reduce degranulation even when exposed to a plasma atmosphere.

  ADVANTAGE OF THE INVENTION According to this invention, the plasma-resistant member with big mechanical strength can be provided in the plasma-resistant member exposed to plasma atmosphere. As a result, there exists an effect that generation | occurrence | production of degranulation from a plasma-resistant member can be suppressed and reduced.

The words used in this case are explained below.
(Crystal structure)
In the present invention, the crystal structure refers to a crystal structure that is measured by an X-ray diffraction method or an electron beam diffraction method and is identified by using JCPDS (ASTM) data as an index.
(Polycrystalline)
In the present invention, polycrystal means a structure in which crystallites are joined and integrated. A crystallite substantially constitutes a single crystal, and its diameter is usually 5 nm or more. However, the case where the fine particles are taken into the structure without being crushed rarely occurs, but is substantially polycrystalline.
(interface)
In the present invention, the interface refers to a region constituting a boundary between crystallites.
(Grain boundary layer)
In the present invention, the grain boundary layer refers to a layer having a thickness (usually several nm to several μm) located at the grain boundary referred to as an interface or a sintered body, and usually has an amorphous structure different from the crystal structure in the crystal grain. In some cases, impurities are segregated.
(Anchor part)
In the present invention, the anchor portion refers to the unevenness formed at the interface between the base material and the brittle material structure, and in particular, when forming the brittle material structure instead of forming the unevenness on the base material in advance, The irregularities formed by changing the surface accuracy of the base material.
(Fine particles)
In the present invention, the fine particles mean particles having an average particle size of 10 μm or less identified by particle size distribution measurement or a scanning electron microscope when the primary particles are dense particles. When the primary particles are porous particles that are easily crushed by impact, the average particle size is 50 μm or less. The powder means a state where the above-mentioned fine particles are naturally aggregated.
(aerosol)
In the present invention, the aerosol is a dispersion of the aforementioned fine particles in a gas such as helium, nitrogen, argon, oxygen, dry air, or a mixed gas thereof, and it is desirable that the primary particles are dispersed, Usually, the primary particles include aggregated particles. The gas pressure and temperature of the aerosol are arbitrary, but the concentration of fine particles in the gas is from 0.0003 mL / L to 0 at the time of injection from the nozzle when the gas pressure is converted to 1 atm and the temperature is converted to 20 ° C. It is desirable for structure formation to be in the range of 0.06 mL / L.
(At normal temperature)
In the present invention, the normal temperature refers to a room temperature environment that is substantially lower than the sintering temperature of yttrium oxide and is substantially 0 ° C. to 100 ° C.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. First, a method for manufacturing a structure made of a yttrium oxide polycrystal formed on a substrate will be described with reference to FIGS.

FIG. 4 is a schematic configuration diagram of a manufacturing apparatus for forming a structure composed of a yttrium oxide polycrystal, and various gas cylinders 11 of nitrogen, dry air, and helium are connected to an aerosol generator 13 via a transport pipe 12, Further, a nozzle 15 is disposed in the structure forming apparatus 14 through the transport pipe 12. A base material 16 installed on the XY stage 17 is disposed at the tip of the nozzle 15 so as to face the nozzle 15 with an interval of 10 mm. The structure forming chamber 14 is connected to an exhaust pump 18.

And after filling raw material powder in the aerosol generator 13, the gas cylinder 11 is opened, gas is introduce | transduced into the aerosol generator 13 through the conveyance pipe 12, and the aerosol which disperse | distributed raw material powder in gas is generated. This aerosol is further transported in the direction of the structure forming chamber 14 through the transport pipe 12, and the raw material powder is sprayed toward the base material 16 from the nozzle 15 while being accelerated at a high speed.

  Next, a more preferable method for producing a structure made of a yttrium oxide polycrystal formed on a substrate will be described.

  As the gas sealed in the gas cylinder 11, helium, nitrogen, argon, oxygen, dry air, or a mixed gas thereof can be used, but it is more preferable to use helium or nitrogen.

  The raw material powder incorporated in the aerosol generator 13 is more preferably produced by using yttrium oxide fine particles having an average particle size of the order of sub-μm and aluminum oxide fine particles having an average particle size of the order of μm.

The crystal structure of the structure made of the yttrium oxide polycrystal manufactured using the above-described manufacturing apparatus has a monoclinic system strongest line intensity with respect to a cubic system strongest line intensity in X-ray diffraction. The intensity ratio (monoclinic strongest line strength / cubic strongest line strength) is more preferably 1 or more.

The structure composed of yttrium oxide polycrystal produced by using the above-mentioned production apparatus generates chamber, bell jar, susceptor, clamp ring, focus ring, capture ring, shadow ring, insulating ring, dummy wafer, and high-frequency plasma. Tube, dome for generating high-frequency plasma, high-frequency transmission window, infrared transmission window, monitoring window, end point detection monitor, lift pin to support semiconductor wafer, shower plate, baffle plate, bellows cover, upper electrode, lower electrode It can be used for a semiconductor or liquid crystal manufacturing apparatus member exposed to a plasma atmosphere such as metal, ceramics, semiconductor, glass, quartz, resin, and the like. Furthermore, the structure made of the yttrium oxide polycrystal according to the present invention can be used for an electrostatic chuck such as an etching apparatus that performs fine processing on a semiconductor wafer or a quartz wafer.

Hereinafter, embodiments of the present invention will be described using examples. In this example, a mixed powder of yttrium oxide fine particles and aluminum oxide fine particles having a larger particle diameter than that was used as a raw material powder for forming a structure made of yttrium oxide polycrystal.

(Example)
Yttrium oxide fine particles and aluminum oxide fine particles were prepared. The 50% average particle diameter of the aluminum oxide fine particles based on the volume was 5.9 μm, and the average particle diameter of the yttrium oxide fine particles was 0.47 μm. Here, the 50% average particle size based on the volume is the particle size distribution measurement data measured using a laser diffraction particle size distribution meter when the cumulative volume of fine particles from the smaller particle size reaches 50%. The particle size of the fine particles. Moreover, the average particle diameter of the yttrium oxide fine particles is a particle diameter calculated from the specific surface area measured with a Fischer sub-sieve sizer.

Next, a mixed powder in which these fine particles were mixed at a number ratio of (aluminum oxide fine particles) :( yttrium oxide fine particles) = 1: 100 was obtained.

The aluminum oxide fine particles function as film forming auxiliary particles, and are used to deform or crush the yttrium oxide fine particles to form a new surface. After the collision, the structure is directly reflected except for those that are inevitably mixed. Therefore, the material is not limited to aluminum oxide, and yttrium oxide may be used, but aluminum oxide is optimal in consideration of cost.

The above mixed powder is loaded into the aerosol generator of the production apparatus shown in FIG. 4, and aerosol is generated while flowing nitrogen gas as a carrier gas at a flow rate of 5 liters / minute on the aluminum alloy substrate. Erupted. Thus, a structure made of yttrium oxide polycrystal having a height of 25 μm and an area of 20 mm × 20 mm was formed on the substrate.

FIG. 1 is an X-ray diffraction pattern of a structure made of a yttrium oxide polycrystal prepared using a mixed powder mixed at a number ratio of (aluminum oxide fine particles) :( yttrium oxide fine particles) = 1: 100. FIG. 2 is an X-ray diffraction pattern of fine yttrium oxide particles used as a raw material powder for producing a structure made of a yttrium oxide polycrystal. FIG. 3 is an X-ray diffraction pattern of a yttrium oxide sintered body (HIP-treated product).

The crystal structure of the structure made of the yttrium oxide polycrystal produced by the above method is a mixture of cubic and monoclinic. On the other hand, the crystal structure of the raw material powder and the yttrium oxide sintered body was only cubic.

Further, in FIG. 1, from the strongest peak intensity attributed to the cubic system (cubic) seen in the vicinity of 2θ = 29 ° and the strongest peak intensity attributed to the monoclinic system (monoclinic) seen in the vicinity of 2θ = 30 °, The intensity ratio of the monoclinic strongest line intensity / cubic strongest line intensity was 1.04.

The Vickers hardness measurement results of the above samples are shown in Table 1. Vickers hardness was measured with a test force of 50 gf using a dynamic ultra-micro hardness meter (DUH-W201 / Shimadzu Corporation). Rather than a yttrium oxide sintered body composed only of a cubic system (cubic), the yttrium oxide polycrystalline body in which a cubic system and a monoclinic system (monoclinic system) prepared according to the present invention are mixed is used. The resulting structure had a greater hardness.

The adhesion strength of the structure made of the yttrium oxide polycrystal produced according to the present invention was measured by the following method. A cylindrical rod made of SUS is cured at 120 ° C. for 1 hour using epoxy resin on the surface of the structure composed of yttrium oxide polycrystal, and the cylindrical rod is tested using a desktop small testing machine (EZ Graph / manufactured by Shimadzu Corporation). The evaluation was made by pulling in the 90 ° direction. The adhesion strength F was calculated by the following formula.
F = (4 / πr ³ ) × h × f
Here, r is the radius of the cylindrical rod, h is the height of the cylindrical rod, and f is the test force at the time of peeling.
The adhesion strength of the structure composed of the yttrium oxide polycrystal formed on the aluminum alloy base material was 80 MPa or more and had very excellent adhesion strength.

FIG. 4 is an X-ray diffraction pattern of a structure made of a yttrium oxide polycrystal produced using a mixed powder mixed in a number ratio of (aluminum oxide fine particles) :( yttrium oxide fine particles) = 1: 100 according to the present invention. 3 is an X-ray diffraction pattern of fine yttrium oxide particles which are raw material powders used in the production of a structure made of the yttrium oxide polycrystal of the present invention. It is an X-ray-diffraction pattern of a yttrium oxide sintered compact (HIP processing goods). It is the schematic of the apparatus which produces the structure which consists of a yttrium oxide polycrystal of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Gas cylinder 12 ... Conveyance pipe 13 ... Aerosol generator 14 ... Structure formation apparatus 15 ... Nozzle 16 ... Base material 17 ... XY stage 18 ... Exhaust pump

Claims (2)

A plasma-resistant member that requires plasma resistance, and a plasma-resistant structure is formed at least on the surface exposed to the plasma, and this plasma-resistant structure is mainly composed of yttrium oxide polycrystal. In addition, there is a structure having substantially no glassy grain boundary layer at the interface between the crystals of the polycrystal, and the crystal structure of the yttrium oxide polycrystal is cubic and monoclinic. A plasma-resistant member comprising a mixture of monoclinic materials. 2. The plasma-resistant member according to claim 1, wherein an anchor portion into which a part of the yttrium oxide polycrystal is bitten is formed.

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