Plasma processing device, method for operating plasma processing device, inspection device, and inspection method

Abstract

The purpose of the present invention is to provide technology for nondestructively and contactlessly evaluating the state of a member for a plasma processing device, and showing evaluation results to a user of the plasma processing device.　A plasma processing device according to the present invention is a plasma processing device in which a member having, on a surface thereof, a coating film containing Y and O is provided in a processing chamber for processing a wafer using plasma. The plasma processing device includes a control unit that reports that damage or wear of the coating film has reached a certain value or reports the life of the member when the absorption intensity of infrared rays of a predetermined wavelength detected from the surface of the coating film of the member is a minimal value.

Description

Plasma processing apparatus, method for operating a plasma processing apparatus, inspection apparatus, and inspection method

[0001] The present invention relates to a plasma processing apparatus that forms plasma in a processing chamber inside a vacuum vessel and processes a sample to be processed, such as a semiconductor wafer, placed in the processing chamber; a method for operating the plasma processing apparatus; an inspection apparatus; and an inspection method.

[0002] In the process of manufacturing electronic devices and magnetic memory by processing semiconductor wafers (hereinafter also simply referred to as "wafers"), plasma etching (hereinafter also referred to as "plasma etching") is used for the fine processing required to form circuit structures on the wafer surface. As devices become more highly integrated, such plasma etching processes are increasingly required to have higher precision and yield.

[0003] The walls of the processing chamber in a plasma etching apparatus are exposed to high-frequency plasma and etching gas during the etching process. Therefore, the inner wall surface is protected by a coating with excellent plasma resistance. Conventional technologies related to materials for such plasma-resistant coatings include the following:

[0004] Patent Document 1 describes that the material constituting the film covering the surface of the grounding portion disposed inside the plasma etching apparatus contains a Group IIIA element (at least one selected from Sm, Eu, Gd, Tb, Dy, Ho, Er, Y, Tm, Yb, Lu as the main component) and a fluorine element, contains a Group IIIA fluoride phase, and the fluoride phase has an orthorhombic crystal phase and contains 50% or more of the crystal phase belonging to the space group Pnma. Specifically, Patent Document 1 discloses the following contents as the invention of a fluoride-containing film, a covering member, and a method for forming a fluoride-containing film. "A film containing at least a Group IIIA element and a fluorine element, containing a Group IIIA fluoride phase, and the fluoride phase has an orthorhombic crystal phase and contains 50% or more of the crystal phase belonging to the space group Pnma, characterized as a Group IIIA element fluoride-containing film. According to the present invention, in a film containing a fluoride of Group IIIA on the surface of a member exposed to an atmosphere where corrosive halogen species exist, by controlling the state of the crystal phase, color change due to corrosion can be suppressed. Thus, by including a crystal phase in the Group IIIA element fluoride-containing film, the corrosion resistance can be improved. Further, by making the crystal phase orthorhombic and substantially a single phase, it is also possible to suppress the color change of the film. Also, by making the hardness of the film 100 or more in terms of hardness Hv by the micro-Vickers method, the wear amount of the film can be reduced and suppressed."

[0005] Patent Document 2 states that the film on the surface of the grounding portion disposed inside the plasma etching apparatus is made of a material containing any one or two or more of Al ２ O ３ , YAG, Y ２ O ３ , Gd ２ O ３ , Yb ２ O ３ Or YF ３ Patent Document 3 states that Y ３ Al ５ O １２ , Y ４ Al ２ O ９ , Er ２ O ３, Gd ２ O ３ , Y ２ O ３ , Er ３ Al ５ O １２ , Gd ３ Al ５ O １２ , YF ３ or Nd ２ O ３ , Y ４ Al ２ O ９ and Y ２ O ３ -ZrO ２ It is described that the material is composed of a solid solution. Specifically, Patent Document 2 discloses the following invention for an etching apparatus and an etching chamber component, with the objective of "providing an etching apparatus that improves the yield of processing by suppressing the generation of foreign matter." "An etching apparatus that etches a sample placed in a processing chamber inside a vacuum container using plasma, comprising a component placed inside the processing chamber and a coating formed by thermal spraying a predetermined material, covering the surface of the component and facing the plasma, the coating having a surface that is sealed using the same material as the predetermined material." Furthermore, Patent Document 3 discloses the following invention for strengthening plasma spray coatings using plasma flame heat treatment. "A method for forming a plasma-resistant ceramic coating on an article includes the step of placing the article in a chamber or a spray cell of a plasma spraying system. Thereafter, ceramic powder is supplied into the plasma spraying system at a certain powder supply rate, and the plasma-resistant ceramic coating is deposited on at least one surface of the article by the plasma spraying system during the plasma spraying process. Thereafter, the plasma spraying system is used to perform in-situ plasma flame heat treatment of the plasma-resistant ceramic coating to form a crust on the plasma-resistant ceramic coating."

[0006] Patent Document 4 describes that the material of the surface coating on the grounding part of a plasma etching apparatus includes yttrium fluoride and yttrium oxyfluoride. Patent Document 4 addresses the problem of "suppressing the generation of minute particles in a plasma process that introduces a gas containing halogen and oxygen gas," and discloses the following inventions for a plasma processing apparatus and a plasma processing method. "A plasma processing apparatus 10 is provided, comprising a processing container 12 capable of reducing pressure, a lower electrode that also serves as a mounting table 20 on which a wafer W is placed in the processing container, an upper electrode or antenna electrode positioned opposite the lower electrode, a gas supply source 32 for introducing a gas containing halogen gas and oxygen gas into the processing container, a high-frequency power source 18 for applying high-frequency power for plasma generation to at least one of the electrodes of the upper electrode, antenna electrode or lower electrode, and means for plasmaizing the gas with the high-frequency power for plasma generation and plasma processing the wafer on the mounting table by the action of the plasma, wherein at least a part or all of the surface exposed to the plasma in the processing container, at a height on the upper electrode side, the antenna electrode side or the lower electrode side from the wafer placement position, is coated with a fluorine compound."

[0007] Patent documents 5, 6, and 7 describe the use of yttrium oxide, yttrium fluoride, and oxyyttrium fluoride, each having an average crystallite size of less than 100 nm, as a coating material for the ground portion placed inside a plasma etching apparatus, by aerosol deposition. The aerosol deposition method is also known to have the advantage of reducing surface irregularities compared to the atmospheric pressure plasma spraying method described above. Specifically, Patent document 5 states that the objective is to "provide a plasma-resistant member that can increase the adhesion strength or adhesion force of a coating covering the inner wall of a chamber, or reduce particles," and discloses the following as an invention of a plasma-resistant member: "A plasma-resistant member is provided, comprising a substrate and a layered structure formed on the surface of the substrate and containing yttria polycrystalline material and having plasma resistance, wherein the layered structure has a first uneven structure and a second uneven structure formed superimposed on the first uneven structure and having finer irregularities than the first uneven structure." Furthermore, Patent Document 6 aims to provide a plasma-resistant member that can reduce particles and stably maintain chamber conditions, and discloses the following invention for a plasma-resistant member and a method for manufacturing the same: "A plasma-resistant member is provided comprising a substrate and a layered structure having plasma resistance, which includes yttria polycrystalline material formed on the surface of the substrate by an aerosol deposition method, wherein the yttria polycrystalline material constituting the layered structure has a crystalline structure in which cubic and monoclinic crystals are mixed, the ratio of monoclinic crystals to cubic crystals in the yttria polycrystalline material constituting the layered structure is 0% or more and 60% or less, and the crystallite size of the yttria polycrystalline material constituting the layered structure is 8 nm or more and 50 nm or less." Furthermore, Patent Document 7 aims to provide a structure that can enhance plasma resistance, and discloses the following invention for a structure."A structure is provided in which a polycrystalline yttrium oxyfluoride having an orthorhombic crystal structure is the main component, and the average crystallite size of the polycrystalline material is less than 100 nanometers, wherein when the peak intensity detected by X-ray diffraction at a diffraction angle of 2θ = 32.0° is denoted as γ and the peak intensity detected at a diffraction angle of 2θ = 32.8° is denoted as δ, the peak intensity ratio γ / δ is 0% or more and 150% or less."

[0008] On the other hand, Non-Patent Document 1 discloses that increasing the average crystallite size increases the amount of foreign matter generated.

[0009] Patent Document 9 discloses a range of specific mixing ratio values ​​of yttrium fluoride granules and yttrium oxide granules as a thermal spray material that can obtain a yttrium-based fluoride compound thermal spray coating that has sufficient corrosion resistance to plasma and can effectively prevent damage to the base material due to acid penetration during acid cleaning. Patent Document 10 also discloses a process for manufacturing a yttrium fluoride thermal spray coating that can suppress particle generation, which involves supplying a slurry containing yttrium fluoride particles having an average particle size within a specific range to a position downstream from the nozzle of a thermal spray gun that emits a flame in a high-velocity flame thermal spray method, or to the tip of the nozzle of a thermal spray gun that emits a plasma jet in an atmospheric pressure plasma thermal spray method, along the central axis of the nozzle. Specifically, Patent Document 9 discloses the following as an invention of a yttrium-based fluoride thermal spray coating and a corrosion-resistant coating including said thermal spray coating. "A yttrium-based fluoride thermal spray coating formed on the surface of a substrate with a thickness of 10 to 500 μm, characterized by an oxygen concentration of 1 to 6% by mass and a hardness of 350 HV or higher. It exhibits excellent corrosion resistance in a halogen-based gas atmosphere or halogen-based gas plasma atmosphere, effectively prevents substrate damage due to acid penetration during acid cleaning, and minimizes the generation of reaction products and particles due to detachment from the coating."

[0010] Patent Document 11 discloses a method of forming a thermal spray coating on parts, components, etc., within a plasma etching apparatus using a suspension plasma spraying (SPS, also called suspension plasma spraying or suspension plasma spraying) method, in which rare earth aluminum monoclinical (R4Al2O9), in which some of the Al atom sites of rare earth (R) atoms are replaced with rare earth (R) atoms, is used as a raw material and sprayed in the form of a slurry dispersed in a dispersion solvent. Specifically, Patent Document 11 discloses the following as an invention relating to a thermal spray material, a method for manufacturing the same, and a method for forming a thermal spray coating. "This thermal spray coating contains rare earth elements (R), aluminum, and oxygen, and includes a crystalline phase of a composite oxide containing rare earth elements and aluminum. The crystalline phase of the composite oxide containing rare earth elements and aluminum has a composition richer in rare earth elements than the stoichiometric composition of rare earth-aluminum monoclinic (R4Al2O9), in which some of the Al atom sites of rare earth elements (R) are replaced by rare earth elements (R). This thermal spray coating generates a small amount of particles through reaction with halogen-based gas plasma, and can form a highly corrosion-resistant thermal spray coating with excellent plasma etching resistance. Such a thermal spray coating is excellent for forming on parts and components in plasma etching equipment used in semiconductor manufacturing processes."

[0011] Japanese Patent Publication No. 2004-197181, Japanese Patent Publication No. 2009-176787, Japanese Patent Publication No. 2016-539250, Japanese Patent Publication No. 2013-140950, Japanese Patent Publication No. 2014-141390, Japanese Patent Publication No. 2016-27624, Japanese Patent Publication No. 2018-82154, Japanese Patent Publication No. 2017-190475, Japanese Patent Publication No. 2017-150085, Japanese Patent Publication No. 2020-172702

[0012] Kazuhiro Ueda, Kazuyuki Ikenaga, Tomoyuki Tamura, and Masahiro Kadoya, "Study on the Crystal Structure and Foreign Matter Generation Mechanism of Yttrium-Based Materials for Plasma Etching Equipment," The Japan Society for Analytical Chemistry X-ray Analysis Research Group (ed.), Advances in X-ray Analysis 50, Agne Technical Center, Publication Date: April 1, 2019, pp. 197-205.

[0013] When a plasma processing device is used for an extended period, the surface of the inner wall material is exposed to plasma containing N, O, F, H, Cl, Br, etc. The collision of slow-energy ions can cause the inner wall material surface to become amorphous, or the inner wall material surface may be sputtered, with atoms from the sputtered material reattaching to the inner wall material surface. In such cases, the inner wall material surface corrodes due to the plasma reaction, degrading its plasma-resistant coating and potentially becoming a source of foreign matter. Even if the average crystal size of the inner wall material is reduced, microcrystals may be removed by the plasma reaction, leaving larger crystals on the inner wall material surface, which can also become a source of foreign matter.

[0014] Furthermore, in the case of grounding components placed in plasma processing equipment, it is not possible to evaluate the deterioration of the grounding component surface non-destructively and non-contactively. Therefore, in order to suppress the generation of foreign matter, it is necessary to replace the grounding component after a certain period of operation. However, it has not been sufficiently considered that the deterioration status differs depending on the quality of the component when new and the conditions of use, such as when a large amount of foreign matter is generated before replacement, or when the deterioration of the grounding component after replacement is evaluated and it is found that there is still plenty of time before foreign matter is generated. Therefore, the object of the present invention is to provide a technology that evaluates the condition of components for plasma processing equipment non-destructively and non-contactively and shows the evaluation results to the user of the plasma processing equipment.

[0015] To solve the above problems, one representative plasma processing apparatus of the present invention is a plasma processing apparatus comprising a member having a coating containing Y and O on its surface in a processing chamber for processing wafers using plasma, and comprising a control unit that notifies when the absorption intensity value of infrared rays of a predetermined wavelength detected from the surface of the coating on the member becomes minimal, indicating that the damage or wear of the coating has reached a certain value, or that the lifespan of the member has ended.

[0016] According to the present invention, the condition of components for a plasma processing apparatus can be evaluated non-destructively and non-contact, and the evaluation results can be shown to the user of the plasma processing apparatus. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments for carrying out the invention.

[0017] Figure 1 is a schematic longitudinal cross-sectional view showing the configuration of the plasma processing apparatus according to Embodiment 1 of the present invention. Figure 2 is a schematic longitudinal cross-sectional view showing the plasma processing apparatus when the vacuum is released. Figure 3 is a diagram showing an example of the spectrum of the measured infrared absorption intensity. Figure 4 is at 1300 cm⁻¹. －１ From 1800cm －１ This figure shows an enlarged view of the wavenumber region. Figure 5 shows 1300 cm². －１ From 1800cm －１ This figure shows the difference between the background interpolated from the infrared absorption intensity in the wavenumber region. Figure 6 is a summary of the infrared absorption intensity of Y-O bonds for samples from different manufacturers and under different plasma processing conditions. Figure 7 shows the result when clustering is applied to Figure 5. Figure 8 shows the relationship between the peak value of infrared absorption intensity and the normalized lifetime of past data. Figure 9 is at 1300 cm⁻¹. －１ From 1800cm －１ This figure shows the correlation between the peak value of infrared absorption intensity clustered in the wavenumber region and the normalized lifetime. Figure 10 shows the correlation at 1300 cm⁻¹. －１ From 1800cm －１ This figure shows the correlation between the peak value of infrared absorption intensity clustered in the wavenumber region and the normalized lifetime. Figure 11 shows the line profile of the STEM-EDX cross-section of the coating. Figure 12 shows the STEM image of the coating. Figure 13 shows an example of a model diagram of the coating. Figure 14 shows an example of the configuration of the control unit of the plasma processing apparatus. Figure 15 shows a flowchart of the operation method of the plasma processing apparatus. Figure 16 is a longitudinal cross-sectional view showing a schematic of the configuration of the plasma processing apparatus according to Embodiment 2 of the present invention. Figure 17 is a schematic diagram showing the case in which the vacuum of the processing chamber of the plasma processing apparatus is broken, the earth electrode is removed, and the infrared absorption intensity is measured.

[0018] (Example 1) (Configuration of Plasma Processing Apparatus) Example 1 of the present invention will be described with reference to Figures 1 to 6. Figure 1 is a schematic longitudinal cross-sectional view showing the configuration of the plasma processing apparatus 100 according to Example 1 of the present invention. The plasma processing apparatus 100 includes a processing chamber 5 for processing a wafer 3 using plasma 13, and a member (earth electrode 22) on which a coating containing Y and O is provided on its surface. A detailed explanation follows below.

[0019] The plasma processing apparatus 100 of Example 1 comprises a vacuum vessel having a cylindrical portion, a plasma forming section arranged above or to the side of the cylindrical portion and surrounding it, and a vacuum exhaust section located below the vacuum vessel and including a vacuum pump for exhausting the inside of the vacuum vessel. Inside the vacuum vessel is a processing chamber 5, which is a space where plasma is formed, and is configured to communicate with the vacuum exhaust section.

[0020] The upper part of the processing chamber 5 is a space surrounded by a cylindrical inner wall, forming a discharge chamber where the plasma 13 is formed.

[0021] Below the discharge chamber where the plasma 13 is generated, inside the processing chamber 5, there is a stage 4, which is a sample holder on which the wafer 3, the substrate to be processed, is placed and held on its upper surface.

[0022] The stage 4 of Embodiment 1 is a cylindrical member whose vertical central axis is positioned concentrically with or approximately concentric with the discharge chamber when viewed from above. A space is left between the bottom surface of the processing chamber 5, which has an opening that communicates with the vacuum exhaust section, and the lower surface of the stage 4. The stage 4 is held at an intermediate position between the upper and lower ends of the processing chamber 5 in the vertical direction. The space inside the processing chamber 5 below the stage 4 is connected to the discharge chamber through a gap between the side wall of the stage 4 and the cylindrical inner wall surface of the processing chamber 5 that surrounds it. This space constitutes an exhaust path through which products generated on the upper surface of the wafer 3 and in the discharge chamber during processing of the wafer 3 above the upper surface of the stage 4, as well as plasma and gas particles in the discharge chamber, pass and are discharged to the outside of the processing chamber 5 by the vacuum exhaust section.

[0023] The stage 4 of Example 1 has a base material which is a cylindrical metal member, and a heater (not shown) is placed inside a dielectric film that covers the upper surface of the base material, and multiple refrigerant channels (not shown) are arranged concentrically or spirally around the central axis inside the base material. Furthermore, with the wafer 3 placed on the upper surface of the dielectric film of the stage 4, a heat-conducting gas such as He is supplied to the gap between the lower surface of the wafer 3 and the upper surface of the dielectric film. For this reason, piping (not shown) through which the heat-conducting gas flows is arranged inside the base material and the dielectric film.

[0024] Furthermore, the substrate of stage 4 is connected via a coaxial cable through an impedance matcher 11 to a high-frequency power supply 12, which supplies high-frequency power to form an electric field above the upper surface of the wafer 3 to induce charged particles in the plasma during plasma processing of the wafer 3. In addition, above the heater in the dielectric film above the substrate, a film-like electrode is arranged, to which DC power is supplied to generate an electrostatic force within the dielectric film and the wafer 3 to attract and hold the wafer 3 to the upper surface of the dielectric film. The film-like electrode is arranged symmetrically around the central axis in the radial direction from the central axis in the vertical direction of multiple regions from the vertical central axis of the substantially circular upper surface of the wafer 3 or stage 4, and each is configured to be given a different polarity.

[0025] Above the upper surface of the stage 4 in the processing chamber 5, opposite to it, is a window member 2 made of a dielectric material such as quartz or ceramics, which forms the upper part of the vacuum vessel and airtightly seals the inside and outside of the processing chamber 5. Furthermore, below this window member 2, at a position that forms the ceiling surface of the processing chamber 5, is a shower plate 1 made of a dielectric material such as quartz, which is a disc shape and has a gap 6 between it and the lower surface of the window member 2, and has a plurality of through holes 7 in its center.

[0026] The gap 6 is connected to the vacuum vessel so as to communicate with the processing gas supply pipe 25, and a valve 26 for opening or closing the inside is positioned at a predetermined location on the processing gas supply pipe 25. The flow rate or velocity of the processing gas supplied to the processing chamber 5 is regulated by a gas flow rate control means (not shown) connected to one end of the processing gas supply pipe 25. After flowing into the gap 6 through the processing gas supply pipe 25 with the valve 26 open, the gas diffuses inside the gap 6 and is supplied from above into the processing chamber 5 through the through hole 7.

[0027] Below the vacuum vessel, a vacuum exhaust section is located to discharge gas and particles from inside the processing chamber 5 through an exhaust port, which is an exhaust opening positioned directly below the stage 4 on the bottom surface of the processing chamber 5, with its vertical central axis being approximately the same. The vacuum exhaust section includes a pressure adjustment plate 14, which is a disc-shaped valve that moves up and down above the exhaust port to increase or decrease the area of ​​the flow path through which gas flows into the exhaust port, and a turbomolecular pump 10, which is a vacuum pump. Furthermore, in the vacuum exhaust section, the outlet of the turbomolecular pump 10 is connected to a dry pump 9, which is a roughing pump, via an exhaust pipe, and a valve 16 is positioned on the exhaust pipe.

[0028] The pressure adjustment plate 14 in Embodiment 1 also serves as a valve for opening and closing the exhaust port. The vacuum vessel is equipped with a pressure detector 27, which is a sensor for detecting the pressure inside the processing chamber 5. The signal output from the pressure detector 27 is transmitted to a control unit (not shown) to detect the pressure value, and based on the command signal output from the control unit according to that value, the pressure adjustment plate 14 is driven to change its vertical position, thereby increasing or decreasing the area of ​​the exhaust flow path. The control unit will be described later. Of the valves 15 and 17 connected to the exhaust piping 8, valve 17 is a slow exhaust valve for slowly evacuating the processing chamber 5 from atmospheric pressure to a vacuum using a dry pump 9, and valve 15 is a main exhaust valve for high-speed exhaust using a dry pump 9.

[0029] Above the cylindrical portion at the top of the vacuum vessel constituting the processing chamber 5, and surrounding the side walls, are configurations for forming an electric or magnetic field supplied to the processing chamber 5 to form plasma. Specifically, above the window member 2, a waveguide 19 is arranged, which is a conduit through which the microwave electric field supplied to the processing chamber 5 propagates. A magnetron oscillator 18 that oscillates and outputs a microwave electric field is located at one end of the waveguide 19. The waveguide 19 comprises a rectangular waveguide section with a rectangular longitudinal cross-section and an axis extending horizontally, with the magnetron oscillator 18 located at one end, and a circular waveguide section connected to the other end of the rectangular waveguide section, with a central axis extending vertically and a circular cross-section. The lower end of the circular waveguide section has a cylindrical shape with an enlarged diameter, and a cavity is located inside in which the electric field of a specific mode is strengthened. Multiple stages of solenoid coils 20 and 21, which are magnetic field generating means, are provided above and around the cavity, as well as around the sides of the processing chamber 5.

[0030] In such a plasma processing apparatus 100, the unprocessed wafer 3 is transported into the processing chamber 5 by being placed on the tip of an arm of a vacuum transport device (not shown), such as a robot arm, located inside a transport chamber inside a vacuum transport container, which is another vacuum container (not shown) connected to the side wall of the vacuum container, and then handed over to the stage 4 and placed on its upper surface. When the arm of the vacuum transport device exits the processing chamber 5, the inside of the processing chamber 5 is sealed, and the wafer is held on the dielectric film by the electrostatic force generated by applying a DC voltage to the electrodes for electrostatic adsorption in the dielectric film. In this state, a gas with heat-conducting properties, such as He, is supplied to the gap between the wafer 3 and the upper surface of the dielectric film that constitutes the upper surface of the stage 4 through piping located inside the stage 4, and a refrigerant whose temperature is adjusted to a predetermined range by a refrigerant temperature controller (not shown) is supplied to the internal refrigerant flow path. This promotes heat transfer between the temperature-controlled substrate and the wafer 3, and the temperature of the wafer 3 is adjusted to a value within an appropriate range for starting processing.

[0031] The gas flow rate or velocity of the processing gas, adjusted by the gas flow rate control means, is supplied to the processing chamber 5 through the processing gas supply pipe 25 and through the gap 6 and through hole 7. At the same time, the turbomolecular pump 10 operates to exhaust the inside of the processing chamber 5 from the exhaust port, and the balance between the two adjusts the pressure inside the processing chamber 5 to a value within a range suitable for processing. In this state, the microwave electric field emitted from the magnetron oscillator 18 propagates inside the waveguide 19, passes through the window member 2 and shower plate 1, and is radiated into the processing chamber 5. Furthermore, the magnetic field generated by the solenoid coils 20 and 21 is supplied to the processing chamber 5, and the interaction between this magnetic field and the microwave electric field causes electron cyclotron resonance (ECR), exciting the atoms or molecules of the processing gas, which then ionize and dissociate, generating plasma 13 inside the processing chamber 5.

[0032] When plasma 13 is formed, high-frequency power from high-frequency power supply 12 is supplied to the substrate, forming a bias potential above the upper surface of wafer 3. Charged particles such as ions in the plasma 13 are attracted to the upper surface of wafer 3, and the etching process of the film layer to be processed in a film structure having multiple film layers, including the film layer to be processed and a mask layer, which are pre-formed on the upper surface of wafer 3, proceeds along the pattern shape of the mask layer. When a detector (not shown) detects that the processing of the film layer to be processed has reached its endpoint, the supply of high-frequency power from high-frequency power supply 12 is stopped, the plasma 13 is extinguished, and the processing is stopped.

[0033] When the control unit determines that further etching of wafer 3 is unnecessary, high-vacuum evacuation is performed. Furthermore, after static electricity is removed and the adsorption of wafer 3 is released, the arm of the vacuum transfer device enters the processing chamber 5 to receive the processed wafer 3, and as the arm retracts, wafer 3 is transported out to the vacuum transfer chamber outside the processing chamber 5.

[0034] (Treatment of the inner wall surface of the processing chamber 5) The inner wall surface of such a processing chamber 5 is a surface that faces the plasma 13 and is exposed to its particles. On the other hand, in order to stabilize the potential of the dielectric plasma 13, it is necessary to place a component that functions as a ground electrode facing and in contact with the plasma inside the processing chamber 5.

[0035] In the plasma processing apparatus 100 of Example 1, a ring-shaped member, the earth electrode 22, is positioned to cover the lower surface of the inner wall of the processing chamber 5 surrounding the discharge chamber and to surround it above the upper surface of the stage 4. This earth electrode 22 is positioned to function as an earth electrode. The earth electrode 22 comprises a base material 23 made of a conductive material and a coating 24 covering its surface. In Example 1, the base material 23 of the earth electrode is made of a metal such as stainless steel alloy or aluminum alloy.

[0036] If the surface of the base material 23 of such an earth electrode 22 does not have a coating, exposure to the plasma 13 at that point can cause corrosion and the generation of foreign matter that contaminates the wafer 3. Therefore, in order to suppress contamination, a coating 24 made of a highly plasma-resistant material is placed over the surface of the base material 23 of the earth electrode 22. This coating 24 covering the base material 23 allows the earth electrode 22 to maintain its function as a plasma-mediated electrode while suppressing damage caused by the plasma.

[0037] The coating 24 may be a laminated film. In Example 1, yttrium fluoride YF was applied to the surface of the base material 23 of the earth electrode 22. ３ A coating 24 was used, which was deposited and formed by atmospheric pressure plasma spraying using fine particles of yttrium oxyfluoride (YOF) as the spraying material. In the following description, the coating 24 may be referred to as the YF inner wall material. The case of the YF inner wall material of the earth electrode 22 will be described, but this disclosure is not limited to this case. This disclosure can be applied to components placed in the processing chamber 5 of the plasma processing apparatus 100 other than the earth electrode 22, and can be applied to coatings for protecting components from plasma processing, without being limited to the type of coating.

[0038] On the other hand, even in the substrate 28 which does not have a grounding function, metal components such as stainless steel alloys and aluminum alloys are used. The surface of the substrate 28 is also subjected to treatments such as passivation, thermal spraying, physical vapor deposition (PVD), and chemical vapor deposition (CVD) to improve corrosion resistance to plasma and reduce wear, in order to suppress corrosion, metal contamination, and the generation of foreign matter caused by exposure to the plasma 13.

[0039] Furthermore, in order to reduce the interaction between the substrate 28 and the plasma 13, a cylindrical ceramic cover (not shown) made of yttrium oxide, quartz, or the like may be placed between the inner wall surface of the cylindrical substrate 28 and the discharge chamber. By placing such a cover between the substrate 28 and the plasma 13, contact with highly reactive particles in the plasma 13 and collisions with charged particles are blocked or reduced, thereby suppressing wear on the substrate 28.

[0040] (Evaluation of the state) Figure 2 is a longitudinal cross-sectional view showing a schematic of the plasma processing apparatus 100 when the vacuum is released. During maintenance, the processing chamber 5 of the plasma processing apparatus 100 is vacuum-broken by introducing nitrogen gas, inert gas, or air, and the upper part of the processing chamber 5 is lifted by a crane (not shown) to the state shown in Figure 2. At this time, without touching the coating 24 of the earth electrode 22, the spectrum of infrared intensity reflected and scattered on the surface of the coating 24 is measured using a Fourier transform infrared absorption spectrometer 29. The inspection device 30 evaluates the state of the coating 24 of the earth electrode 22 using the measured spectrum.

[0041] Referring to Figures 3 to 10, the procedure for processing the measured infrared absorption spectrum in the inspection device 30 will be explained. Figure 3 is a diagram showing an example of the spectrum of the measured infrared absorption intensity. In Figure 3, the vertical axis represents the infrared absorption intensity (receivability), and the horizontal axis represents the infrared wavenumber. Figure 3 shows the infrared absorption intensity spectra of a new coating (graph labeled "New"), a coating used for about half of its predicted lifespan (graph labeled "In Use"), and a coating used to its predicted lifespan (graph labeled "Degraded"). Y is registered in the Fourier Transform Infrared Spectroscopy (FT-IR) database. ２ O ３ The transmission absorption spectrum is at 2930 cm⁻¹. －１ 1384cm －１ 563cm －１ , 465cm －１ , 450cm －１ The absorption of YF ３ The transmission absorption spectrum is 417 cm⁻¹. －１ and 401cm －１ The absorption is shown in Figure 3 at 2930 cm. －１ The absorption is due to the broad absorption of the O-H bond (3000-3750 cm⁻¹). －１ ) and absorption of C-H bonds (2750-3000 cm) －１ It overlaps with ) and therefore cannot be detected. Also, 700 cm －１ In the following region, absorption is high and the background slope is steep, so absorption peaks could not be detected. 1300 cm －１ From 1800cm －１ In the wavenumber region, there is Y-O coupling infrared absorption. Figure 4 shows the infrared absorption spectrum extracted in this wavenumber region.

[0042] Next, Figure 4 shows 1300 cm －１ From 1800cm －１ This figure shows an enlarged view of the wavenumber region. In the figure, the background differs depending on the manufacturer and the plasma processing room used, so 1300 cm⁻¹ is used. －１ The infrared absorption intensity and 1850 cm －１The background was interpolated using two points of infrared absorption intensity. The results are also shown in Figure 4. Note that "1300 cm －１ From 1800cm －１ The notation "1300 to 1800 cm" －１ It is sometimes written as "[...]". The same applies to other wavenumber regions.

[0043] Next, Figure 5 shows 1300 cm －１ From 1800cm －１ This figure shows the result of subtracting the interpolated background from the infrared absorption intensity in the wavenumber region. By subtracting the background, the peaks included in the infrared absorption intensity are highlighted.

[0044] Next, Figure 6 shows a summary of the infrared absorption intensity of Y-O bonds in samples from different manufacturers and under different plasma processing conditions. It can be seen that there are 2 to 6 peaks, although this varies depending on the sample. The peaks were identified, the wavenumber regions in which the peaks were contained were classified, and the samples were clustered into six types ((1) to (6)).

[0045] Next, Figure 7 shows the result of searching for peaks according to the clustering in Figure 5. The six vertical lines indicate the positions of the peaks detected within the clustered range. Since the number of peaks detected differs depending on the spectrum, for spectra where no peaks were detected, interpolation was performed using the spectral intensity at the average wavenumber in the clustered wavenumber region.

[0046] Next, Figure 8 shows the relationship between the peak value of infrared absorption intensity and the normalized lifetime of past data. Figure 8 shows the 1592 cm⁻¹ of Y-O bonds for samples from different manufacturers and under different plasma processing conditions. －１ The graph shows the results of plotting the infrared absorption intensity on the vertical axis and the normalized lifespan (1 representing new, 0 representing no remaining lifespan) on the horizontal axis, which is the normalized lifespan of the coating used relative to the lifespan predicted from new. The curve shown in Figure 8 is a regression curve, and it can be seen that the infrared absorption intensity takes a minimum value around a normalized lifespan of 0.4. Figure 8 also shows the results for the coating shown in Figure 7.

[0047] Figures 9 and 10 show 1300 cm－１ From 1800cm －１ This figure shows the correlation between the peak value of infrared absorption intensity and the normalized lifetime when clustered in the wavenumber region. Figure 9(a) shows clustering (1) at 1355 cm⁻¹. －１ Nearby, Figure 9(b) shows clustering (2) at 1437 cm. －１ Nearby, Figure 9(c) shows clustering (3) at 1536 cm. －１ Nearby, Figure 10(a) shows clustering (4) 1592 cm －１ Nearby, Figure 10(b) shows clustering (5) at 1641 cm. －１ Nearby, Figure 10(c) shows clustering (6) at 1738 cm². －１ This shows the correlation between the peak value of infrared absorption intensity in the vicinity and the normalized lifetime. It can be seen that in all clustered wavenumber regions, the peak value has a minimum around the normalized lifetime of 0.4. The time elapsed from new to the time the peak value becomes minimum (usage time) corresponds to a period of 0.6 for a normalized lifetime of 1. If we set the usage time to 1, it can be seen that the remaining lifetime is less than 2 / 3 of the usage time. On the other hand, there are differences in the intensity difference between new and minimum values ​​depending on the peak. This difference is largest at 1592 cm⁻¹ in Figure 10(a). －１ It was the peak in the vicinity.

[0048] (Consideration of the mechanism of infrared absorption peaks) Based on the analysis results of the absorption intensity of Y-O bonds, we consider a degradation model of the YF inner wall material. Here, as a first approximation, we consider that when the Y-F bonds on the surface of the YF inner wall material decrease and the Y-O bonds increase, the peak intensity shown on the vertical axis of Figures 9 and 10 increases, and conversely, when the Y-F bonds increase, the absorption intensity of Y-O bonds decreases, and the peak value on the vertical axis of Figures 9 and 10 decreases.

[0049] Figure 11 shows the line profile of the cross-sectional STEM-EDX of the coating 24. The cross-sectional STEM-EDX shows the results of analysis performed by combining scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. Figure 11(a) is the line profile of the cross-sectional STEM-EDX of a new coating sample with a normalized lifetime of 1.0. In the 0.0–0.02 μm region, the O concentration increases and the concentrations of Y and F decrease due to the effect of minute irregularities on the surface of the coating 24. In the 0.02–0.038 μm region, the O concentration is thought to be high due to the effect of spontaneous oxidation. In the 0.04–0.09 μm region, there is some variation in the concentrations of O and F, but it is thought to be the same as the interior from 0.09 μm onwards, with Y at approximately 25 at%, O at 20 at%, and F at 55 at%.

[0050] Figure 12 shows a STEM image of the coating 24. Figure 12(a) corresponds to the STEM image of a new coating 24 shown in Figure 11(a), where Figure 11(a)(1) is a bright-field image and Figure 11(a)(2) is a Z-contrast image. The line profile in Figure 11(a) was measured at the white line portion in Figure 12(a). It is shown that the surface of the coating 24 has an uneven surface.

[0051] Figure 13 shows an example of a model diagram of the coating 24. The upper part of the paper shows the surface of the base material s of the coating 24, excluding the uneven parts and naturally oxidized parts, and the lower part of the paper shows the interior of the coating 24. Figure 13(a) shows the state of the base material s shown in Figures 11(a) and 12(a) as a model diagram. "Y-O-F ３ This indicates the approximate ratio of O and F concentrations when the amount of Y contained in the base material s of the coating 24 is set to 1.

[0052] When the surface of the coating 24 is fluorinated by plasma treatment, the absorption intensity of the Y-O bond decreases until it reaches approximately the normalized lifetime of 0.4, as shown in Figures 9 and 10. Figure 13(b) shows a model diagram of the base material s near the normalized lifetime. It is thought that the absorption intensity of the Y-O bond decreases while the coating 24 is fluorinated up to about 3 μm from the surface. ０．６-F ５ " assumes a case where the F concentration increases by approximately 60% and the O concentration decreases by approximately 40% in the surface portion of the base material s. Here, the detection depth of FT-IR is considered to be about half of the wavelength of the infrared ray used in FT-IR (about 3 μm). This is Y ２ O ３ , YF ３ and Y ５ O ４ F ７ Materials such as those constituting the YF inner wall material, etc., are almost transparent to visible light to infrared rays, but the inner wall surface has irregularities of several μm and contains a large number of voids and grain boundaries inside. Therefore, they are scattered at those boundaries and specular reflection is not detected. The penetration depth of infrared rays is considered to be about the wavelength (about 6 μm), but it is estimated to be about half of the wavelength considering the length of the path escaping from the surface.

[0053] When plasma treatment is repeatedly performed, the state of the coating 24 deteriorates and it becomes unsuitable for use as the ground electrode 22. Fig. 11(b) shows the line profile of the cross-sectional STEM-EDX of the sample with a normalized life = 0. The O concentration is high from the surface of the coating 24 to a depth of 0.022 μm, but inside 0.022 μm, the O concentration gradually decreases and the F concentration increases. On the other hand, since the inside has the same element concentration as the new product, it means that the O concentration increases and the F concentration decreases inside.

[0054] Fig. 12(b) corresponds to the STEM image of the coating 24 with a normalized life = 0 shown in Fig. 11(b), where Fig. 11(b)(1) is the bright field image and Fig. 11(b)(2) is the Z contrast image. The line profile in Fig. 11(b) is measured from the white line portion in Fig. 12(b). Compared with the state of the new product in Fig. 12(a), it is inferred that there are no irregularities on the surface side of the coating 24 and the surface has deteriorated due to exposure to plasma.

[0055] Fig. 13(c) shows the state of the base material s shown in Fig. 11(b) and Fig. 12(b) as a model diagram. That is, at a normalized life of 0.4 to 0, fluorination progresses from the inner wall surface to a region deeper than 3 μm ("Y-O ０．６ -F ５), the area of "" shifted inward, and only the fluorine supplied by diffusion from the surface became insufficient for the internal fluorination, and the fluorine in the fluorine-rich layer on the surface was replaced by the internal oxygen, and as a result, the surface was oxidized (it was measured as if an area where oxidation progressed to "Y - O ３ - F ２．７ " was formed on the surface of the base material s).

[0056] Y ２ O ３ expands in volume when fluorinated, and contracts in volume when YOF is oxidized. That is, at the boundary of the "Y - O ０．６ - F ５ " region in FIG. 12, especially at the boundary between the "Y - O ０．６ - F ５ " region and the "Y - O ３ - F ２．７ " region, a large residual stress (tensile stress in the stacking direction) will occur, and it is considered that cracks will occur in this region and foreign substances due to deterioration will occur.

[0057] (Configuration example of the control unit) FIG. 14 is a diagram showing an example of the configuration of the control unit 50 of the plasma processing apparatus 100. The control unit 50 includes a memory 51, a communication device 52, an input / output device 53, and a processor 54.

[0058] The memory 51 has a set of software programs and / or instructions to be executed by the processor 54. The processor 54 executes various software programs and / or instruction sets stored in the memory 51 to execute various functions for the plasma processing apparatus 100 and process data. The memory 51 includes a non-volatile storage device such as a random access memory (RAM), a magnetic disk storage device, a flash memory device, or other non-volatile solid-state memory devices. Although the case where the plasma processing apparatus 100 includes one memory 51 and one processor 54 each is shown, there may be two or more. Also, the plasma processing apparatus 100 may include a storage device other than the memory 51.

[0059] The communication device 52 is an interface for communicating information with the components of the plasma processing apparatus 100 and with external devices. For example, the control unit 50 receives a signal output from the pressure detector 27 via the communication device 52 and outputs a control signal to drive the pressure adjustment plate 14. The control unit 50 also manages the progress of the etching process, and when the etching process is completed, the control unit 50 controls the arm of the vacuum transfer device via the communication device 52. Furthermore, based on the information obtained via the communication device 52, the control unit 50 can measure the time elapsed since the material was placed in the processing chamber 5 and measure the number of wafers 3 processed in the plasma processing apparatus 100.

[0060] The input / output device 53 is used by the user to input and output information to the plasma processing device 100. The input / output device 53 can be, for example, an output device such as a display, or an input device such as a keyboard or mouse. Alternatively, it may be a device that has both input and output functions, such as a touch panel.

[0061] The memory 51 stores software programs and / or instruction sets for executing the functions of the plasma processing apparatus 100, and data used to execute the functions. The memory 51 includes a plasma processing management unit 510, a spectrum measurement unit 511, a background interpolation unit 512, a background difference unit 513, a usage period measurement unit 514, a life determination unit 515, a notification unit 516, an FT-IR database 517, and a parts database 518.

[0062] When the plasma processing management unit 510 is executed by the memory 51, the processor 54 manages the plasma processing performed on the wafer 3. For example, the processor 54 operates the plasma processing apparatus 100 according to the plasma processing conditions set by the user of the plasma processing apparatus 100. The processor 54 can also acquire set data, such as the cumulative time during which plasma 13 was generated in the plasma processing, the number of wafers 3 processed, and the usage period of components placed in the plasma processing apparatus 100.

[0063] When the spectrum measurement unit 511 is executed by the processor 54, the processor 54 performs a spectrum measurement. The processor 54 uses a Fourier transform infrared absorption spectrometer 29 to measure the spectrum of infrared intensity reflected and scattered at the surface of the coating 24 of the earth electrode 22.

[0064] Furthermore, when the background interpolation unit 512 is executed by the processor 54, the processor 54 interpolates the background of the infrared absorption intensity. The processor 54 selects a predetermined wavenumber region from the infrared reflection intensity acquired by the spectrum measurement unit 511, selects two points, and interpolates the background. Here, the FT-IR database 517 registers infrared transmission absorption spectra for various substances. In this disclosure, information on the transmission absorption spectra of compounds containing Y, O, or F is registered, but the FT-IR database 517 may also register information on the transmission absorption spectra of other compounds. In addition, the FT-IR database 517 may also register background information corresponding to the material manufacturer or the plasma processing in the plasma processing apparatus 100. Based on the information registered in the FT-IR database 517, the processor 54 can select a wavenumber region and set the background.

[0065] Furthermore, when the background difference unit 513 is executed by the processor 54, the processor 54 subtracts the interpolated background from the infrared absorption intensity in a predetermined wavenumber region. The processor 54 also clusters the predetermined wavenumber region and detects the peak value of the infrared absorption intensity at a predetermined wavelength. In sections where the infrared absorption intensity cannot be measured, the processor 54 interpolates using the spectral intensity at the average wavenumber in the clustered wavenumber region. In this disclosure, the predetermined wavelength is 1300 to 1850 cm⁻¹. -１ This is the wavelength within which the reflectance value is maximized (peak value). The predetermined wavelength range may be set according to the material of the component used to detect the state.

[0066] Furthermore, when the usage period measurement unit 514 is executed by the processor 54, the processor 54 measures the usage period elapsed since the ground electrode 22 was placed in the plasma processing apparatus 100. As an indicator of the usage period, for example, the number of wafers 3 processed since the ground electrode 22 was placed in the processing chamber 5 or the sum of the time (cumulative time) for which the plasma 13 was formed since the ground electrode 22 was placed in the processing chamber 5 can be used. The processor 54 measures the number of wafers 3 that have been plasma processed and the cumulative time for which the plasma 13 was formed.

[0067] Furthermore, when the life determination unit 515 is executed by the processor 54, the processor 54 determines that the value of the infrared reflection intensity of a predetermined wavelength detected from the surface of the coating 24 of the earth electrode 22 is at a minimum. The processor 54 repeatedly performs processing by the spectrum measurement unit 511, the background interpolation unit 512, and the background difference unit 513 to detect the peak value of the infrared reflection intensity and detects that the peak value is at a minimum. For example, if the repeatedly detected peak value changes from decreasing to increasing as the usage period progresses, it is possible to detect a minimum of the peak value. When a minimum is detected, it is determined that the normalized life of the earth electrode 22 has become 0.4 or less.

[0068] Furthermore, when the notification unit 516 is executed by the processor 54, the processor 54 notifies that the damage or wear of the coating 24 of the earth electrode 22 has reached a certain value, or the usable limit (e.g., lifespan) of the earth electrode 22, when the value of the absorption intensity of infrared rays of a predetermined wavelength detected from the surface of the coating 24 of the earth electrode 22 becomes minimal. The notification will include the degree of damage or wear caused by the change in the composition of Y, O, and F contained on the surface of the coating 24 after the value of the absorption intensity of infrared rays of a predetermined wavelength becomes minimal. For example, the user of the plasma processing apparatus 100 may be notified of indicators such as the damage rate or wear rate compared to the condition of a new earth electrode 22. The processor 54 can also output information about the lifespan of the coating 24 or the earth electrode 22 to a display or the like among the input / output devices 53. Information regarding the lifespan will be described later.

[0069] In this way, the user of the plasma processing apparatus 100 can determine the degree of damage or wear to the coating 24, or the lifespan of the ground electrode 22, when damage accumulates to the coating 24 as the number of wafers 3 processed or the total time the plasma 13 is formed increases after the ground electrode 22 is placed in the processing chamber 5.

[0070] (Lifespan of components) When the peak value of the infrared absorption intensity is at its minimum, the normalized lifespan is around 0.4, and the ground electrode 22 has remaining capacity to perform plasma processing. In this case, the lifespan of the ground electrode 22 can be indicated, for example, by the number of wafers that can be processed before maintenance of the ground electrode 22, or by the total time during which plasma 13 can be formed before maintenance of the ground electrode 22. In this disclosure, since damage occurs due to plasma processing, the lifespan of the ground electrode 22 has the same meaning as the lifespan of the coating 24. In the case of maintenance of the coating 24, the ground electrode 22 itself may be replaced, or the coating 24 on the ground electrode 22 may be changed to a new one.

[0071] For example, the total number of wafers 3 that can be processed and the total time of plasma formation 13 that can be formed from the start of use of the ground electrode 22 until it is replaced are registered in the parts database 518. In addition, the control unit 50 measures the cumulative number of wafers processed and the plasma formation time until a minimum peak value of the reflectance is detected.

[0072] If the starting point is the notification time in step S7, the control unit 50 can set the number of wafers that can be processed from the notification in step S7 to the maintenance work on the coating 24 to be smaller than the number of wafers until it is determined that the absorption intensity value has become minimum. Alternatively, if the control unit 50 indicates the lifespan of the component (earth electrode 22) by the total time during which plasma 13 can be formed from the notification in step S7 to the maintenance work on the coating 24, it can set the total time during which plasma 13 is formed to be smaller than the total time during which plasma 13 is formed until it is determined that the absorption intensity value has become minimum. Furthermore, if the control unit 50 uses the point in time when the minimum peak value of infrared absorption intensity is detected as the starting point, and the control unit 50 indicates the lifespan of the component (earth electrode 22) by the number of wafers 3 that can be processed from the time it is determined that the absorption intensity has become minimum until the maintenance work on the coating 24, it sets the number of wafers due to lifespan to be smaller than the number of wafers 3 until it is determined that the absorption intensity has become minimum. Alternatively, if the control unit 50 indicates the lifespan of the component (earth electrode 22) by the total time during which plasma 13 can be formed from the time it is determined that the absorption intensity has become minimum until the maintenance work on the coating 24, it sets the total time due to lifespan to be smaller than the total time during which plasma 13 was formed until it is determined that the absorption intensity has become minimum.

[0073] In this way, the control unit 50 converts the lifespan of the ground electrode 22 (coating 24) into the number of wafers 3 that can be processed or the remaining time for plasma 13 to be formed until maintenance work is required, and notifies the user of the plasma processing apparatus 100. The user can intuitively understand the lifespan of the ground electrode 22 (coating 24) and recognize the urgency and promptness of the maintenance work.

[0074] Although the configuration of the control unit 50 has been described above, the inspection device 30 may have a configuration that includes at least a memory 51 and a processor 54, similar to the control unit 50. The inspection device 30 may perform the same processing as the control unit 50 to inspect the state of the earth electrode 22.

[0075] (Flowchart of the operation method of the plasma processing apparatus 100) Figure 15 is a flowchart of the operation method of the plasma processing apparatus 100. In step S1, the material is placed in the processing chamber 5 of the plasma processing apparatus 100. The processing chamber 5 of the plasma processing apparatus 100 is sealed, and the plasma processing apparatus 100 is ready to perform plasma processing on the wafer 3.

[0076] Next, in step S2, the usage period elapsed since the component was placed in the processing chamber 5 is measured. As an indicator of the usage period, for example, the number of wafers processed since the ground electrode 22 was placed in the processing chamber 5 or the sum of the time since the ground electrode 22 was placed in the processing chamber 5 until the plasma 13 was formed can be used. The processing from step S3 to step S6 after step S2 is repeated, and the usage period is measured.

[0077] Next, in step S3, a spectrum measurement is performed. For example, the control unit 50 measures the infrared intensity spectrum of the ground electrode 22 located inside the processing chamber 5.

[0078] Next, in step S4, background interpolation is performed. For example, the control unit 50 interpolates the background in a specific wavelength range from the measured infrared absorption intensity.

[0079] Next, in step S5, background subtraction is performed. For example, the control unit 50 takes the background subtraction interpolated in a specific wavelength range and detects the peak intensity of the infrared absorption intensity.

[0080] Next, in step S6, a minimum peak value is detected. For example, the control unit 50 can detect a minimum peak value when the repeatedly detected peak value changes from decreasing to increasing. If a minimum peak value is not detected (No in step S6), the measurement of the usage period is continued (steps S7 and S2), and the detection of peak intensity is repeated (steps S3 to S5).

[0081] Next, in step S8, notification is given to the user of the plasma processing apparatus 100. For example, if a minimum peak value is detected (Yes in step S6), the control unit 50 notifies the user of the plasma processing apparatus 100 of the extent of damage or wear to the coating 24, or the lifespan (usable limit) of the earth electrode 22 (coating 24).

[0082] Although the above operating method has been described in the case where it is controlled by the control unit 50 of the plasma processing apparatus 100, it is also possible to perform the above operating method using the inspection apparatus 30.

[0083] (Effects) As described above, in the plasma processing apparatus 100 of Example 1, with respect to infrared radiation scattered and reflected from the components placed in the processing chamber 5, 1300 cm² －１ From 1800cm －１ An infrared absorption spectrum including the wavenumber region was measured at 1300 cm². －１ The infrared absorption intensity and 1800 cm －１ The background is interpolated using two points of infrared absorption intensity. Next, 1437 cm －１ 1536cm －１ 1592cm －１ , 1641cm －１ The infrared absorption intensity is measured by subtracting the background, which is interpolated from the absorption intensity of the surrounding infrared radiation, and it is detected that this infrared absorption intensity decreases as the plasma processing time increases. Next, it is detected that the peak value of the infrared absorption intensity has become minimum or increased, and it is determined that the normalized lifespan has become 0.4 or less. A normalized lifespan of 0.4 or less means that the remaining time until the lifespan of the inner wall material is exhausted and foreign matter is generated is less than two-thirds of the total usage time. By informing the user of the plasma processing apparatus 100 of the remaining lifespan, the user can be made aware of the condition of the components placed in the processing chamber 5.

[0084] Furthermore, by positioning the Fourier transform infrared absorption spectrometer 29 on a movable arm and measuring the absorption and scattering of infrared rays at multiple locations on the inner wall material of the ground electrode 22, it is possible to evaluate the variation within the ground electrode 22 and detect the location where the deterioration is most advanced.

[0085] In this way, according to this disclosure, the condition of components for a plasma processing apparatus can be evaluated non-destructively and non-contact, and the evaluation results can be shown to the user of the plasma processing apparatus.

[0086] (Example 2) Example 2 will be described with reference to Figure 16. Figure 16 is a longitudinal cross-sectional view showing a schematic configuration of the plasma processing apparatus 200 according to Example 2 of the present invention. Example 2 differs from Example 1 in that it can measure the infrared absorption intensity without breaking the vacuum of the processing chamber 5 of the plasma processing apparatus. In Example 2, the plasma processing apparatus 200 further includes a first window (window 42) for irradiating infrared rays onto a member placed in the processing chamber 5, a second window (window 43) for emitting infrared rays scattered from the member to the outside of the processing chamber 5, and a detector (IR detector 41) for detecting infrared rays emitted from the second window (window 43). In the following description, the same or equivalent components as in Example 1 above will be denoted by the same reference numerals, and their descriptions will be simplified or omitted.

[0087] The plasma processing apparatus 200 includes an IR laser light source 40 and an IR detector 41, and windows 42 and 43 are formed in the substrate 28. Infrared rays (IR) emitted from the IR laser light source 40 are introduced into the processing chamber 5 through a window 42 (e.g., Ge, Si, etc.) that transmits long-wavelength infrared rays. Similarly, infrared rays (SL) scattered by the YF inner wall material are also detected by the IR detector 41 through a window 43 (e.g., Ge, Si, etc.) that transmits long-wavelength infrared rays. In the case of window materials with low plasma resistance, such as Ge or Si, a gate valve (not shown) may be placed between the window material and the processing chamber 5 to isolate the window material from the processing chamber 5, so that the window material is not exposed to plasma during plasma processing.

[0088] Furthermore, the incident infrared (IR) is either continuous light parallelized by the optical system, or 1300 cm². －１ , 1800cm－１ The wave number in between, for example, 1592 cm －１ A monochromatic laser with three or more wavenumbers may also be used. The incident infrared (IR) light is irradiated onto the coating 24 at the upper end of the earth electrode 22. The infrared (SL) light scattered at the earth electrode 22 is detected by an IR detector 41 (for example, a deuterated triglycine sulfate (DTGS) detector) through the window material of the window 43.

[0089] The inspection device 30 detects the minimum peak intensity of absorption intensity for the detected infrared SL, similar to Example 1. For example, the background is 1300 cm². －１ and 1800cm －１ The absorption intensity of infrared light from a monochromatic laser of a given wavenumber is used for interpolation. Furthermore, 1592 cm⁻¹ is used as the infrared light of a predetermined frequency. －１ The infrared absorption intensity of a monochromatic laser of a given wavenumber is measured, and the interpolated background is subtracted. The normalized lifetime and 1592 cm⁻¹ are calculated. －１ The correlation of the peak intensities is similar to the correlation shown in Figure 8.

[0090] (Effects) By using the above configuration, it is possible to evaluate the components inside the processing chamber 5 without breaking the vacuum vessel of the plasma processing apparatus 200.

[0091] (Example 3) Example 3 will be described using Figure 17. Figure 17 is a schematic diagram showing the case in which the ground electrode 22 is removed after the vacuum in the processing chamber of the plasma processing apparatus and the infrared absorption intensity is measured. Figure 17(a) is a perspective view and Figure 17(b) is a longitudinal cross-sectional view.

[0092] In Example 3, the spectrum of infrared intensity reflected and scattered at the surface of the coating 24 is measured using a Fourier transform infrared absorption spectrometer 29 without touching the coating 24 of the ground electrode 22. In Example 1, as shown in Figure 2, the Fourier transform infrared absorption spectrometer 29 is positioned on a movable arm and irradiates the ground electrode 22 with infrared light. On the other hand, in Example 3, as shown in Figure 17, the ground electrode 22 is positioned on a platform that is movable in the up / down / left / right and rotational directions, and the absorption and scattering of infrared light at multiple locations on the inner wall material of the ground electrode 22 is measured with the Fourier transform infrared absorption spectrometer 29 fixed in place.

[0093] (Effects) By doing so, it becomes possible to evaluate the variation in the infrared intensity spectrum within the earth electrode 22, and it is also possible to detect the most deteriorated part of the earth electrode 22.

[0094] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0095] The present invention may be described below, but is not limited thereto. (Aspect 1) A plasma processing apparatus comprising a member having a coating on its surface that contains Y and O, in a processing chamber for processing wafers using plasma, wherein the plasma processing apparatus comprises a control unit that notifies when the absorption intensity value of infrared rays of a predetermined wavelength detected from the surface of the coating on the member becomes minimal, that the damage or wear of the coating has reached a certain value, or that the lifespan of the member has reached the end of the lifespan. (Aspect 2) The plasma processing apparatus according to aspect 1, wherein the control unit, when indicating the lifespan of the member by the number of wafers that can be processed from the notification to the maintenance work on the coating, sets the number of wafers due to the lifespan to be smaller than the number of wafers until it is determined that the absorption intensity value has become minimal, or when indicating the lifespan by the total time during which the plasma can be formed from the notification to the maintenance work on the coating, sets the total time due to the lifespan to be smaller than the total time during which the plasma was formed until it is determined that the absorption intensity value has become minimal. (Aspect 3) The plasma processing apparatus according to aspect 1 or 2, wherein the control unit, when indicating the lifespan of the member by the number of wafers that can be processed from the time it is determined that the absorption intensity has become minimal until the maintenance work on the coating, sets the number of wafers due to the lifespan to be smaller than the number of wafers until it is determined that the absorption intensity has become minimal, or when indicating the lifespan of the member by the total time during which the plasma can be formed from the time it is determined that the absorption intensity has become minimal until the maintenance work on the coating, sets the total time due to the lifespan to be smaller than the total time during which the plasma was formed until it is determined that the absorption intensity has become minimal. (Aspect 4) The plasma processing apparatus according to any one of aspects 1 to 3, wherein the control unit notifies the degree of damage or wear caused by a change in the composition of Y, O, and F contained on the surface of the coating after the absorption intensity of infrared rays of a predetermined wavelength has become minimal. (Aspect 5) The predetermined wavelength is 1300 to 1850 cm －１A plasma processing apparatus according to any one of embodiments 1 to 4, wherein the wavelength is such that the absorption intensity value is maximum within the range. (Embodiment 6) A plasma processing apparatus according to any one of embodiments 1 to 5, further comprising: a first window for irradiating infrared rays onto the member placed in the processing chamber; a second window for emitting infrared rays scattered from the member to the outside of the processing chamber; and a detector for detecting infrared rays emitted from the second window. (Embodiment 7) A method for operating a plasma processing apparatus, comprising a member having a coating on its surface that contains Y and O, in a processing chamber for processing a wafer using plasma, wherein when the absorption intensity value of infrared rays of a predetermined wavelength detected from the surface of the coating on the member becomes minimum, the method for operating a plasma processing apparatus is used to notify that the damage or wear of the coating has reached a certain value, or that the lifespan of the member has ended. (Aspect 8) An inspection apparatus for a plasma processing apparatus, comprising a member having a coating on its surface that includes Y and O, in a processing chamber for processing wafers using plasma, wherein the inspection apparatus comprises a memory and a processor, the memory including a processing instruction that causes the processor to execute such an instruction when the value of the absorption intensity of infrared rays of a predetermined wavelength detected from the surface of the coating on the member becomes minimal, thereby indicating that the damage or wear of the coating has reached a certain value, or that the lifespan of the member has been reached. (Aspect 9) An inspection method for an inspection apparatus for a plasma processing apparatus, comprising a member having a coating on its surface that includes Y and O, in a processing chamber for processing wafers using plasma, comprising the process of measuring the usage period elapsed since the member was placed in the processing chamber, measuring the infrared reflection intensity of the member, interpolating the background in a specific wavelength region from the measured infrared absorption intensity, taking the difference of the interpolated background, detecting the peak intensity of the infrared absorption intensity, and detecting the minimum of the peak intensity.

[0096] 1... Shower plate, 2... Window component, 3... Wafer, 4... Stage, 5... Processing chamber, 6... Gap, 7... Through hole, 8... Exhaust piping, 9... Dry pump, 10... Turbomolecular pump, 11... Impedance matching unit, 12... High-frequency power supply, 13... Plasma, 14... Pressure regulating plate, 15... Valve, 16... Valve, 17... Valve, 18... Magnetron oscillator, 19... Waveguide, 20... Solenoid coil, 21... Solenoid coil, 22... Ground electrode, 23... Base material, 24... Coating, 25... Processing gas supply piping, 26... Valve, 27... Pressure detector, 28... Substrate, 40... IR laser light source, 41... IR detector, 42... Window, 43... Window, 50... Processing unit, 51... Memory, 52... Communication device, 53... Input / output device, 54... Processor, 56... Notification unit, 100, 200... Plasma processing unit, 511... Spectrum measurement unit, 512... Background interpolation unit, 513... Background difference unit, 514... Usage period measurement unit, 515... Life determination unit, 516... Notification unit, 517... FT-IR database, 518... Parts database

Claims

1. A plasma processing apparatus comprising a member having a coating containing Y and O on its surface, in a processing chamber for processing wafers using plasma, wherein the plasma processing apparatus comprises a control unit that notifies when the absorption intensity value of infrared rays of a predetermined wavelength detected from the surface of the coating on the member becomes minimal, indicating that the damage or wear of the coating has reached a certain value, or that the lifespan of the member has ended.

2. The plasma processing apparatus according to claim 1, wherein the control unit, when indicating the lifespan of the member by the number of wafers that can be processed from the notification to the maintenance work of the coating, sets the number of wafers due to the lifespan to be smaller than the number of wafers until it is determined that the absorption intensity value has become minimum, or when indicating the lifespan by the total time during which the plasma can be formed from the notification to the maintenance work of the coating, sets the total time due to the lifespan to be smaller than the total time during which the plasma was formed until it is determined that the absorption intensity value has become minimum.

3. The plasma processing apparatus according to claim 1, wherein the control unit, when indicating the lifespan of the member by the number of wafers that can be processed from the time it is determined that the absorption intensity has become minimum until the maintenance work on the coating, sets the number of wafers due to the lifespan to be smaller than the number of wafers until it is determined that the absorption intensity has become minimum, or when indicating the lifespan of the member by the total time during which the plasma can be formed from the time it is determined that the absorption intensity has become minimum until the maintenance work on the coating, sets the total time due to the lifespan to be smaller than the total time during which the plasma was formed until it is determined that the absorption intensity has become minimum.

4. The plasma processing apparatus according to claim 1, wherein the control unit notifies the degree of damage or wear caused by a change in the composition of Y, O, and F contained on the surface of the coating after the value of the absorption intensity of infrared rays of a predetermined wavelength becomes minimal.

5. The predetermined wavelength is 1300 to 1850 cm. －１ A plasma processing apparatus according to any one of claims 1 to 3, wherein the wavelength is such that the absorption intensity value is maximized within the range.

6. The plasma processing apparatus according to claim 1, further comprising: a first window for irradiating infrared light onto the member placed in the processing chamber; a second window for emitting infrared light scattered from the member to the outside of the processing chamber; and a detector for detecting infrared light emitted from the second window.

7. A method for operating a plasma processing apparatus, comprising a member having a coating on its surface that contains Y and O, in a processing chamber for processing wafers using plasma, wherein the method includes a process in which the damage or wear of the coating has reached a certain value, or the lifespan of the member is notified when the absorption intensity of infrared rays of a predetermined wavelength detected from the surface of the coating on the member becomes minimal.

8. An inspection apparatus for a plasma processing apparatus, comprising a member having a coating on its surface that includes Y and O, in a processing chamber for processing wafers using plasma, wherein the inspection apparatus includes a memory and a processor, and the memory includes a processing instruction that causes the processor to execute such an instruction when the absorption intensity value of infrared rays of a predetermined wavelength detected from the coating surface of the member becomes minimal, indicating that the damage or wear of the coating has reached a certain value or that the lifespan of the member has reached a certain level.

9. An inspection method for an inspection apparatus of a plasma processing apparatus, the apparatus comprising a member having a coating containing Y and O on its surface in a processing chamber for processing wafers using plasma, the inspection method comprising: measuring the usage period elapsed since the member was placed in the processing chamber; measuring the infrared reflection intensity of the member; interpolating the background in a specific wavelength region from the measured infrared absorption intensity; taking the difference of the interpolated background to detect the peak intensity of the infrared absorption intensity; and detecting the minimum of the peak intensity.

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