JP2012222225A - Plasma processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide plasma processing equipment capable of suppressing fluoride of a yttria material.SOLUTION: Plasma processing equipment includes: a processing chamber 7; means 10 for supplying a gas to the processing chamber 7; exhaust means 12 for depressurizing the processing chamber 7; high-frequency power 20 and 21 for generating plasma; high frequency bias power 22 and 23 for accelerating ions entering an object to be processed 4; and an inner wall material having a surface coated with yttria 17 and provided in a side wall of the processing chamber. In the equipment, a fluoride detection sensor 30 capable of detecting a degree of fluoride of the yttria in the processing chamber is installed, and a cylindrical component 41 made of quartz is installed in a side wall portion exposed to high-density plasma, and a high conductive material is installed as an earth 52 in a lower part of the side wall of the processing chamber, so that a cleaning time can be adjusted for suppression of fluoride of the yttria 17 and yttria 37 as a reference in cleaning between etching processing.

Description

  The present invention relates to a particle reduction technique in a plasma processing apparatus.

  Plasma etching and plasma CVD are widely used in the manufacturing process of semiconductor devices such as DRAMs and microprocessors. One of the problems in processing a semiconductor device using plasma is to reduce the number of foreign matters attached to an object to be processed such as a semiconductor wafer. For example, when foreign particles fall on the fine pattern of the object to be processed during or before the etching process, the etching of the part is locally inhibited. As a result, a defect such as disconnection occurs in the fine pattern of the object to be processed, resulting in a decrease in yield. For this reason, many countermeasures have been devised that focus on the cause of the generation of foreign particles and a method for preventing the foreign particles from adhering to the wafer by controlling the transport of the generated foreign particles.

  For example, regarding the cause of the generation of foreign particles, a proposal has been proposed in which the surface material of the inner wall is changed to anodized and yttria is used. For example, alumite is gradually consumed by fluorine-based plasma, and aluminum (Al), which is a constituent particle of the consumed alumite, is deposited at a specific location in the processing chamber as AlF combined with fluorine, and is peeled off to form a semiconductor wafer or the like. Adhering to the substrate-like sample to be processed causes contamination by foreign particles. Since the yttria material has a plasma consumption rate as low as about 1/10 compared to the alumite material, contamination by foreign particles can be reduced.

  Further, for example, Patent Document 1 has an exposed surface near the substrate holder that minimizes particle contamination during the processing of the substrate, and the particle contamination of the substrate when the substrate is continuously processed in the plasma processing chamber. And a method of processing a substrate is disclosed.

JP 2008-235924 A

  With the progress of miniaturization of semiconductor devices, it is necessary to reduce foreign particles having a smaller particle size. In general, in a plasma processing apparatus, in general, finer foreign particles tend to generate more.

  Therefore, by changing the inner wall material surface in contact with plasma from anodized to yttria, it is possible to reduce the number of foreign particles when focusing on the same particle size, but by reducing the particle size of foreign particles to be reduced As a result, even when yttria material is used, a new measure for reducing foreign particles is required.

  The generation mechanism of foreign particles due to the use of yttria material as the inner wall material is the same as the case of using alumite material. Consumed due to exposure to fluorine-based plasma, composition containing fluorine in the elements constituting the wall material, that is, deposits in the processing chamber as YFO, and this causes separation to cause contamination of foreign particles .

  In addition, as the particle size of the foreign particles to be reduced is reduced, the inner wall material changes the surface chemical composition (fluorination) by the fluorine plasma, and the inner wall is formed from the inner wall material surface due to this. It is a new problem that the fine particles of the existing members are peeled off.

  An example of a representative one of the present invention is as follows. That is, a processing chamber, a high-frequency power source for generating plasma, a gas supply means for supplying a processing gas into the processing chamber, an exhaust means for exhausting the processing gas, and an object to be processed are placed in the processing chamber. In a plasma processing apparatus having a stage for processing and a part whose surface material is made of yttria on the inner wall of the processing chamber, a fluorination detection sensor for detecting the degree of fluorination of the inner wall is provided on the processing chamber wall This is a plasma processing apparatus.

  The plasma processing apparatus of the present invention includes a processing chamber, a high-frequency power for generating plasma, a processing gas supply function for supplying a processing gas, an exhaust means for decompressing the processing chamber, and an object to be processed. A plasma processing apparatus having a yttria on the inner wall of the processing chamber, and a degree of fluorination of the inner wall on the inner wall of the processing chamber It is characterized by having a fluorination detection sensor for detecting the odor.

  The plasma processing apparatus of the present invention is further characterized in that the fluorination detection sensor uses an FT-IR method, and the surface of the detection portion is coated with yttria having a thickness of 10 nm to 10 μm.

  Further, the plasma processing apparatus of the present invention includes a processing chamber, a high-frequency power for generating plasma, a processing gas supply function for supplying processing gas, an exhaust means for decompressing the processing chamber, and an object to be processed A plasma processing apparatus having an inner wall material in which a yttria film is coated on a metal base material, and a stage wall for processing, and a wafer bias power source for accelerating ions incident on a workpiece The processing chamber wall is composed of a metal base material coated with yttria and a quartz part.

  The plasma processing apparatus of the present invention is further characterized in that a quartz part is installed at a height position where the plasma density is high.

  Further, the plasma processing apparatus of the present invention includes a processing chamber, a high-frequency power for generating plasma, a processing gas supply function for supplying processing gas, an exhaust means for decompressing the processing chamber, and an object to be processed And a wafer bias power source for accelerating ions incident on the object to be processed, and a yttria inner wall material. The processing chamber wall is divided and made of yttria-made parts and conductive parts.

  The plasma processing apparatus of the present invention is further characterized in that SiC is used for the conductive parts.

  The plasma processing apparatus of the present invention is characterized in that the fluorination detection sensor monitors the degree of fluorination of yttria, and determines the end point of cleaning when the degree of fluorination falls below a predetermined value. .

  In the present invention, a fluorination detection sensor that detects the degree of fluorination of the yttria material on the processing chamber wall is installed, and further, in order to suppress the fluorination of the yttria material, a part exposed to high density plasma, a wafer Quartz material is installed in the part where the bias power tends to concentrate, and SiC material is used for the inner wall part that becomes the propagation path of the wafer bias power, thereby reducing the generation amount of foreign particles due to the consumption of the yttria material. And the yield of the semiconductor device can be improved.

FIG. 1 is a diagram showing an outline of a plasma processing apparatus according to a first embodiment of the present invention. FIG. 2 is a diagram showing an outline of the fluorination detection sensor of the present invention. FIG. 3 is a diagram showing a flow for determining the end point of cleaning according to the present invention. FIG. 4 is a view for explaining a state in which yttria on the processing chamber inner wall of the present invention is fluorinated. FIG. 5 is a diagram showing an outline of a plasma processing apparatus according to the second embodiment of the present invention. FIG. 6 is a diagram showing an outline of a plasma processing apparatus according to the third embodiment of the present invention. FIG. 7 is a view for explaining the parts constituting the side wall in the plasma processing apparatus according to the third embodiment of the present invention.

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

  Hereinafter, a first embodiment of a semiconductor manufacturing apparatus according to the present invention will be described with reference to the drawings. First, referring to FIGS. 1 and 2, an outline of the configuration of semiconductor manufacturing to which the present invention is applied will be described.

  FIG. 1 shows a first embodiment in which the present invention is applied to a microwave ECR plasma etching apparatus. FIG. 2 shows an outline of a place where the present invention is applied to a plasma processing apparatus.

  In this plasma processing apparatus, an electric field supply means having a waveguide and an electric field generator for supplying an electric field for generating plasma, solenoid coils 22 and 23 as magnetic field generation means, and plasma is formed inside. A vacuum vessel 1 having a processing chamber 7 in which the wafer 4 is etched is provided. The electric field supply means includes a magnetron oscillator 20 that outputs an electric field generated by a microwave, and a waveguide 21 through which the microwave propagates through the inside of the processing chamber 7.

  The solenoid coils 22 and 23 are disposed so as to surround the processing chamber 7 above and on the side of the vacuum vessel 1 having a cylindrical shape having the processing chamber 7 inside. A stage 6 for placing the wafer 4 to be processed by plasma on the upper surface thereof is disposed in the processing chamber 7. The processing chamber is positioned above the processing chamber 7 and facing the upper surface of the stage 6. A shower plate 2 made of an insulating material such as quartz, which is a disk-shaped member constituting the ceiling surface 7 and provided with a plurality of through holes 9 in the central region thereof, is provided.

  Above the shower plate 2, a disk-shaped plate 3 made of an insulating member such as quartz for constituting the upper part of the vacuum vessel 1 and maintaining the vacuum in the processing chamber 7 is provided. A gap 8 having a predetermined size is formed between the plate 2 and the plate 3.

  The gap 8 is connected to a gas pipe which is a path of a reactive gas introduced into the processing chamber, and the reaction gas whose flow rate is controlled by the gas flow rate control means 10 is introduced into the gap 8 and diffused therein. Then, it passes through a through hole 9 provided in the shower plate 2 and is uniformly supplied into the processing chamber 7 from above.

  The vacuum vessel 1 is provided with pressure detection means 11, which is a sensor for detecting the magnitude of the pressure inside the processing chamber 7, on the side wall of a semiconductor manufacturing apparatus (not shown) that is communicably connected thereto by communication means. The pressure in the processing chamber 7 is detected from the signal output from the pressure detection means 11 in the control unit. A vacuum molecular pump for roughing or vacuuming is provided below the vacuum chamber 1 and communicates with the inside through an opening disposed below the processing chamber 7 and discharges reactive gas, plasma, and products inside the processing chamber 7. Exhaust means 12 composed of a rotary pump or the like is provided, and the amount of reaction gas introduced from the through hole 9 adjusted by the gas flow rate control means 10 and the exhaust inside the processing chamber 7 by the operation of the exhaust means 12 are provided. The pressure in the processing chamber 7 can be adjusted so as to be within a desired value range in accordance with the balance with the quantity speed.

  An electrode made of a disk-shaped conductive member (not shown) is disposed on the stage 6, and this electrode is electrically connected to the high-frequency power supply 14. The impedance matching circuit 13 is connected from the high-frequency power supply 14 during processing of the wafer 4. A high frequency voltage is applied via Although not shown, a dielectric film having a film-like electrode electrically connected to a DC power source (not shown) is disposed on the upper surface of the stage 6 and placed on the upper surface. The wafer 4 is adsorbed and held on the upper surface of the stage 6 by electrostatic force formed by applying DC power to the film-like electrode.

  An inert gas is introduced from the through-hole 9 into the processing chamber 7 through the gas introduction path, and is reduced in pressure by the operation of the exhaust device 12 to a predetermined degree of vacuum. The wafer 4 carried on the arm is placed on the upper surface of the stage 6 and held. In the state where the opening arranged on the side wall of the processing chamber 7 is closed and the inside is sealed, the reactive gas for processing is introduced into the processing chamber through the through hole 9, and the microwave oscillated from the magnetron oscillator 20 is guided. It propagates through the wave tube 21, passes through the plate 3 and the shower plate 2, and is introduced into the processing chamber 7. Further, a magnetic field from the solenoid coils 22 and 23 is introduced into the processing chamber 7, and ECR (Electron Cyclotron Resonance) is generated by the interaction between the electric field generated by the microwave and the magnetic field generated by the solenoid coils 22 and 23. By doing so, the particles of the reactive gas are excited and the plasma 15 is generated.

  When the plasma 15 is formed, the high frequency power from the high frequency power supply 14 is applied to the electrode in the stage 6, and a bias potential is formed between the plasma 15 and the wafer 4. Charged particles such as ions in the plasma 15 are attracted to the surface of the wafer 4 by the potential difference caused by the formed bias potential, and the film layer to be processed placed on the surface of the wafer 4 by the reactive particles such as radicals in the plasma 15. The etching process is started and proceeds under predetermined conditions.

  The side wall of the processing chamber 7 facing the plasma 15 formed in the processing chamber 7 is made of a metal material such as aluminum, and internal fine particles adhere to the plasma 15 or the reactivity in the plasma. Interactions such as physical and chemical reactions with particles occur. If such an interaction proceeds more than necessary, the side wall may be scraped or a product that may adversely affect the wafer 4 may be formed. As a side member, a film 17 made of a ceramic material having high plasma resistance such as yttria is coated with a coating means such as thermal spraying at a thickness of 50 μm to several hundred μm.

  A fluorination sensor 30 for detecting the degree of fluorination of the inner surface member is installed on the side wall of the vacuum container 1 of the present apparatus. The configuration of the fluorination sensor 30 will be described with reference to FIG.

  The window member 33 which is one of the components of the fluorination sensor 30 is a plate-like member made of a light-transmitting material such as quartz, and is disposed on the side wall of the cylindrical portion of the vacuum vessel 1. It is installed inside the through hole so as to face the inside of the processing chamber 7. Further, on the surface of the window member 33 on the side where plasma is generated, a film 37 made of a material such as yttria similar to the inner wall member of the processing chamber 7 has a thickness of 10 nm to 10 μm. Etc. are coated and arranged. In the region of the outer surface opposite to the region of the surface on which the film 37 of the window member 33 is disposed, the reflecting plate 34 is installed in contact therewith.

  The fluorination sensor 30 is provided with a light source 31 for generating infrared light or the like on the atmosphere side portion outside the window member 33, and is irradiated from the light source 31 toward the window member 33. The incident light 35 incident on the inside of the window is incident on the film 37 coated on the inner surface of the window member 33 and is reflected when it slightly penetrates into the inside of the window 37. The incident light 35 is incident on the reflector 34 and reflected again. Incident incident light 35 is thus incident and reflected a plurality of times between the film 37 and the reflecting plate 34 and moves in the window member 33, and then finally is reflected light 36 that is emitted from the outer surface of the window member 33. And enters the detector 32 disposed on the atmosphere side portion outside the window member 33.

  The reflected light 36 is detected by the detector 32, and the spectrum detected from the output and the spectrum of the incident light 35 are compared by a control unit (not shown) to obtain an absorption spectrum such as a change in intensity for each wavelength of the coating 37. The composition / bonding state of the film 37 can be detected from the absorption spectrum. The S / N ratio of the absorption spectrum can be improved by increasing the number of reflections that occur between the film 37 and the reflecting plate 34.

  In this embodiment, the thickness of the film 37 of the detector is in the range between 2 to 3 times the diameter of the particle of foreign matter to be reduced in the processing chamber 7, for example, 50 nm particles are to be reduced. For example, the film 37 preferably has a thickness in the range of 100 to 300 nm. This is because the generation amount of foreign particles greatly depends on the degree of fluorination from the surface of the film 37 to a depth of several times the diameter of the foreign particles.

Next, an operation method of the plasma processing apparatus using the present invention will be described. FIG. 3 shows a processing flow of the wafer 4 performed by the plasma processing apparatus shown in FIG. The reaction gas introduced into the processing chamber 7 during the etching process is, for example, Ar, CHF ₃ , CH ₂ F ₂ , CF ₄ , C ₄ F ₆ , C ₄ F ₈ , C ₅ F ₈ , CO, O ₂ , N ₂ , CH ₄ , CO ₂ , H ₂ , HBr, Cl ₂ , SF _{6 and the} like.

The reaction gas used for these etching processes is selected according to the type of film formed on the wafer. For example, when the etching process is performed using a reactive gas containing fluorine such as CF ₄ gas, the coating is disposed so as to cover the region of the surface facing the plasma 15 of the inner wall member of the processing chamber 7 by the etching process. 17 is fluorinated.

  As a result, as shown in FIG. 4, a fluoride layer 40 is formed on the surface of the film 17 after the etching process is completed. Further, a CFx film or the like is deposited (not shown) on a specific surface of the inner wall of the processing chamber 7.

In this embodiment, after the etching process is completed, a cleaning process is performed to remove deposits such as a CFx film adhering to the surface of the member in the processing chamber 7 and a fluorination relaxation process of the fluorinated layer 40. In the cleaning process, oxygen, SF ₆ gas, or the like is used.

In many cases, it is desirable to reduce the fluorination, that is, reduce YOF to YO after removing the CFx film. In this case, the first cleaning discharge is performed to positively remove the deposited film such as CFx deposited due to the processing gas. Gases introduced into the processing chamber 7 during the first cleaning process for removing the deposited film are O ₂ , Ar, SF ₆ , NF ₃ , CO, CO ₂ , H ₂ , CH ₄ , HBr, N ₂ , Cl ₂ or the like, and one kind of gas or a plurality of gases are mixed and used. For example, for removing a deposited film such as a CFx film, a gas mainly containing oxygen that causes a reaction with carbon (C), for example, O ₂ is used as a single gas, or O ₂ + Ar or the like is used. In this way, a plurality of gases are mixed and used to convert to a substance having high vapor pressure (CO or the like) to remove the deposited film. Further, for example, when the deposited film attached in the processing chamber 7 is not a CFx film but an Si-based deposited film is adhered, a fluorine-based gas that causes a reaction with Si is used to remove the Si-based deposited film. those mainly SF ₆ and NF ₃ or the like containing, for _example, using SF 6, NF ₃ alone gas or _SF 6 ₊ O _2, Cl 2 + _O using a mixture of several gases as _2, etc., The deposited film is removed by converting to a substance having a high vapor pressure (SiFx, SiClx, etc.).

  As described above, the gas used for the cleaning process is selected according to the type of the deposited film attached in the process chamber 7. Therefore, when a deposited film such as a CFx film or a Si-based film is mixed as a deposited film attached in the processing chamber 7, the first cleaning process for removing the deposited film is performed according to the type of the deposited film. The gas introduced into 7 is switched to perform a plurality of cleaning steps.

  In the cleaning process, the spectrum intensity of, for example, F atoms related to the type of deposited film and the gas used for the cleaning process is monitored by detecting the spectrum of light emitted from the inside of the processing chamber 7 by a light receiving device (not shown). When the value becomes equal to or less than a predetermined value, the first cleaning is completed.

Next, as a second cleaning step, the yttria surface that has been fluorinated to become YOF is reduced, that is, returned to the YO composition. Gases introduced into the processing chamber 7 during the fluorination relaxation process, which is the second cleaning step, are O ₂ , Ar, CO, CO ₂ , H ₂ , CH ₄ , HBr, N ₂ , Cl ₂ , SF _6. , NF ₃ , CF _{4 and the} like. The gas containing oxygen has an effect of promoting oxidation and reduction. The gas containing hydrogen has a fluorine removal effect by reaction with fluorine. Among these, for example, O ₂ and Ar are used as a single gas, or a plurality of gases such as O ₂ + Ar and CH ₄ + Ar are mixed and used.

  In the second cleaning process aiming at fluorination relaxation, the end of cleaning is determined using the fluorination sensor 30 shown in FIG. Specifically, after the start of the second cleaning process, infrared light is incident from the light source 31 provided in the fluorination sensor 30 toward the coating 37 on the inner surface of the window member 33 (incident light 35), The absorption spectrum of the film 37 is detected from the output of the detector 32 using the reflected light 36 emitted from the window member 37.

  From the spectrum obtained from the output of the detector 32, when the fluoride layer 40 is present on the surface of the film 17 or 37, an absorption spectrum of fluorine is detected. By repeating these operations, data on temporal change of the absorption spectrum of fluorine is obtained. After the start of the second cleaning, the end of the cleaning process is determined at predetermined time intervals. If the fluorine absorption spectrum is detected to be above a certain reference value level, the second cleaning process is continued. When it is determined that the fluorine absorption spectrum is below a certain reference value level, the second cleaning process is terminated.

  The method for mainly removing the deposited film and mitigating the fluorination of the yttria surface by the first cleaning discharge and the second cleaning discharge has been described above. However, naturally, the fluorination is mitigated during the first cleaning. Needless to say, the removal of the deposited film may proceed simultaneously during the second cleaning. In this case, the emission spectrum detection and the cleaning end determination by the fluorination sensor 30 are performed in parallel.

  Next, a cleaning processing method in the case where the removal of the CFx film deposited film and the relaxation of fluorination are performed in parallel during the cleaning after the etching process will be described.

The gas introduced into the processing chamber 7 during the cleaning process is O ₂ , Ar, CO, CO ₂ , H ₂ , CH ₄ , in order to proceed with the removal of the deposited film of the CFx film and the relaxation of the fluorination in parallel. There are HBr, N ₂ , Cl ₂ , SF ₆ , NF ₃ , CF _{4 and the} like. In the first cleaning process in this case, detection of the emission spectrum and determination of completion of cleaning by the fluorination sensor 30 are performed in parallel, and the spectrum intensity of the F atoms monitored for removal of the deposited film is a predetermined value. When the absorption spectrum of the wavelength corresponding to fluorine of the fluorination sensor 30 that detects fluorination relaxation is below a certain reference value level, that is, the removal of the deposited film and the end determination of the fluorination relaxation treatment When it is determined that both are obtained, the cleaning process is ended according to a command from the control unit. Therefore, when removal of the CFx film deposition and fluorination relaxation proceed simultaneously and sufficient fluorination relaxation is obtained in one stage of the cleaning process, it is necessary to perform fluorination relaxation cleaning. Disappear.

  In the second embodiment of the semiconductor manufacturing apparatus according to the present invention, the description of the same components as those in FIG. 1 is omitted. This will be described with reference to FIG. In the present embodiment, a configuration different from the embodiment of FIG. 1 is that a cylindrical quartz portion that covers a part of the members constituting the side wall of the processing chamber 7 in the circumferential direction is provided. The rate of fluorination of the film 17 increases as the density of the plasma 15 in contact with the surface increases. Accordingly, in the region above the stage 6 in the processing chamber 7 where the plasma 15 is generated, the cleaning process time for fluorination relaxation is long, and the time between the processing of the plurality of wafers 4 is increased, resulting in the semiconductor. There is a problem that the efficiency of processing by the manufacturing apparatus is lowered.

  Therefore, as shown in FIG. 5, a ring-shaped member made of a material having high plasma resistance is detachably disposed on the side wall member of the processing chamber 7 near the top and bottom of the height position where the plasma 15 is generated. is doing. More specifically, the vacuum vessel 1 of the present embodiment is provided with double members inside and outside, and is a cylindrical member on the inside, and the portion constituting the side wall facing the plasma 15 of the processing chamber 7 is adjacent to the top and bottom. The ring-shaped member 41 made of quartz is arranged at a position sandwiched between the cylindrical inner cylinders 40-1 and 40-2 that are connected together.

  The inner cylinders 40-1 and 40-2 are provided with a coating 17 made of a high plasma-resistant material on the surface of the inner wall facing the processing chamber 7 in the same manner as the side wall of the first embodiment. ing. At the lower end portion of the inner side wall of the upper inner cylinder 40-1, a concave portion having a step with the inner side wall recessed by a predetermined size radially outward of the cylinder is disposed.

  Further, the lower end portion on the outer peripheral side of the inner cylinder 40-1 is the upper end of the inner cylinder 40-2 disposed below in a state where the inner cylinders 40-1 and 40-2 are inserted and arranged in the vacuum vessel 1. The inner wall of the processing chamber 7 is formed in contact with the upper surface, and can be regarded as the entire circumference in the circumferential direction on the outer circumferential side surface of the ring-shaped member 41 inside the depression at the lower end of the inner cylinder 40-1. The convex part arrange | positioned over the perimeter to the extent is inserted, and it is clamped between the lower end part of the inner cylinder 40-1, and the upper end part of the inner cylinder 40-2. That is, in the present embodiment, the ring-shaped member 41 is placed on the upper end surface of the lower inner cylinder 40-2, constitutes the inner wall of the processing chamber 7, and faces the plasma 15.

  The portion of the inner peripheral wall surface facing the inside of the processing chamber 7 of the ring-shaped member 41 is a quartz portion having a cylindrical shape that forms a smooth surface, and the size (Ls) of the inner peripheral wall surface is Ls. Of the inner cylinder 40-2 so that at least part of the height position (distance from the lower surface of the shower plate 2) (Hp) of the plasma 15 formed in the range of the height direction of the plasma 15 is arranged. The inner cylinder 40 so that the height of the end surface or the distance from the upper end surface of the inner cylinder 40-1 (or the lower surface of the shower plate 2) to the center in the height direction of the inner peripheral wall surface (the midpoint of Ls) is appropriate. -1, 40-2 and the shape of the ring-shaped member 41 are determined.

  In this embodiment, when assembling the vacuum vessel 1 constituting the processing chamber 7, the lower inner cylinder 40-2 is processed with the plate 3 and the shower plate 2 detached from above the vacuum vessel 1. After the ring-shaped member 41 is placed above the chamber 7, the upper cylinder 40-1 engages the concave portion at the lower end with the ring-shaped convex portion on the outer peripheral side of the ring-shaped member 41. Then, the convex portion is inserted into the concave portion, and the ring-shaped member 41 is sandwiched and held by the inner cylinders 40-1 and 40-2. These members may be provided with a protrusion whose combination is determined for positioning so that the mutual position falls within a predetermined error in the installed state and a recess into which the protrusion is fitted.

  Further, in the ECR discharge type plasma processing apparatus as in this embodiment, the height position (Hp) at which the plasma 15 is generated can be changed by adjusting the magnetic field strength distribution. It is desirable to have a structure in which Ls and Hs can be changed according to the required specifications in accordance with the above processing conditions (magnetic field distribution conditions). For example, a plurality of ring-shaped members 41 having different sizes Ls or a combination of a plurality of pairs of cylinders 40-1 and 40-2 having different vertical heights are used as a set. According to the conditions of processing performed in the processing chamber 7 and the specifications of the wafer 4, an appropriate combination of these is selected in the processing chamber 7 and installed in the vacuum chamber 1 in advance of the processing. It may be. Needless to say, one of the inner cylinders 40-1 and 40-2 has a through hole into which the window member 33 of the fluorination sensor 30 is inserted.

  A third embodiment of the semiconductor manufacturing apparatus according to the present invention will be described with reference to FIGS. Description of the same components as those in FIGS. 1 and 5 is omitted. 6 is replaced with a member constituting the inner wall of the processing chamber 7 coated with yttria in FIGS. 1 and 5, and a cylindrical part made of yttria bulk material is used as the inner wall member of the processing chamber 7. ing.

  FIG. 7 shows an outline of the configuration of the vacuum vessel 1 including the inner cylinders 50-1 and 50-2 having a cylindrical shape constituting the inner wall member of the present embodiment. In this figure, unlike FIGS. 1 and 5, each member is removed from the vacuum vessel 1 and is shown in a state before being combined with each other and installed in the processing chamber 7. The arrangement is shown more clearly.

  In the present embodiment, similarly to the embodiment shown in FIG. 5, inner cylinders 50-1 and 50-2, which are inner side wall members facing the inside of the processing chamber 7, are arranged adjacent to each other in the vacuum chamber 1. And a quartz ring-shaped member 41 held between the two chambers while being installed in the processing chamber 7.

The inner cylinders 50-1 and 50-2 are integrally formed members including ceramics having high plasma resistance, such as yttria (Y ₂ O ₃ ). In particular, in the present embodiment, the ceramics are sintered. It is a member (bulk member) formed in this way. As shown in FIG. 1 and FIG. 5, as a member constituting the side wall of the processing chamber 7, a metal having high conductivity such as aluminum is used as a base material and has a thickness of several hundreds of micrometers. When a coating is placed by coating a high material, wafer bias power with a frequency of several hundred kHz or more is transmitted through the coating and propagates to the base metal such as aluminum. Therefore, the material coated with yttria is grounded. Function as.

  On the other hand, since such an inner wall member functions as a ground, ions accelerated according to the bias power formed on the wafer 4 are incident on the surface of the film, which promotes the progress of fluorination of the film. For this reason, the time required for the treatment for alleviating the fluorination becomes longer and the efficiency of the treatment is lowered. In order to suppress this, in this embodiment, it is desirable to use members (cylinders 50-1 and 50-2) made of the above-described bulk-like plasma-resistant material.

  On the other hand, if a member made of ceramics such as quartz or yttria that does not function as ground when viewed from the wafer bias is used in the processing chamber 7, the ground area inside the processing chamber 7 viewed from the plasma 15 becomes small. When a member having a yttria film is used at a position facing the plasma 15 inside the processing chamber 7, the portion becomes a wafer bias power transmission path, the wafer bias power is concentrated, and the film is rapidly consumed and fluorinated. Proceed to. In order to suppress this, it is necessary to install a member functioning as a ground in the processing chamber 7.

  Therefore, in the embodiment shown in FIG. 6, the position in the height direction of the wafer 4 (the distance of the mounting surface of the wafer 4 from the lower surface of the shower plate 2 or the upper surface of the stage 6) of the processing chamber 7 above the Hw. The inner wall is provided with inner cylinders 50-1 and 50-2 formed of yttria bulk material, and the inner circumference is a side wall including a region in a predetermined range above and below the position of the height Hp of the ECR surface therebetween. A quartz ring-shaped member 41 having a wall surface size Ls was installed. Then, an earth 52 as a ring-shaped member was installed at a height position below the height position Hw of the wafer 4, that is, at a periphery below the placement surface of the stage 6.

  The earth 52 has a flange portion that extends upward at the inner peripheral end portion of the ring-shaped portion and constitutes a cylindrical inner wall. The inner peripheral surface of the lower part of the formed cylinder 50-2 is covered. The height of the upper end of the flange portion is positioned below the height position of the wafer 4 as described above.

  On the other hand, the inner peripheral wall surface of the earth 52 faces the plasma 15 in the processing chamber 7. With such a configuration, it is possible to prevent the above-described problem from occurring due to the earth 52 functioning as a high-frequency power electrode forming a pair of electrodes in the stage 6.

  The earth 52 is preferably made of a material that is less likely to generate foreign particles due to peeling of the material caused by fluorination. For example, a metal such as SiC or stainless steel is a candidate. In particular, SiC is a component of silicon (Si) and carbon (C) that are diffused into the processing chamber by sputtering and deposited at specific locations in the processing chamber, but are removed by discharge using fluorine-based gas or oxygen. Therefore, it is easy to reduce the risk of formation of a deposited film caused by consumption of the inner wall material and generation of foreign particles from the deposited film. Thereby, the fluorination and consumption of the yttria material can be significantly suppressed, and the yield can be improved.

DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Shower plate 3 Plate 4 Wafer 6 Stage 7 Processing chamber 8 Gap 9 Through-hole 10 Gas flow control means 11 Pressure detection means 12 Exhaust means 13 Impedance matching circuit 14 High frequency power supply 15 Plasma 17 Film | membrane 20 Magnetron oscillator 21 Waveguide 22 Solenoid coil 23 Solenoid coil 30 Fluoride sensor 31 Light source 32 Detector 33 Window material 34 Reflector plate 35 Incident light 36 Reflected light 37 Coating 40 Fluoride layer 40-1, 40-2 Inner cylinder 41 Ring-shaped member 50-1, 50-2 Inner cylinder 52 Ground

Claims (7)

A processing chamber, a high-frequency power for plasma generation, a processing gas supply function for supplying a processing gas, an exhaust means for decompressing the processing chamber, a stage for placing a target object, In a plasma processing apparatus having a wafer bias power source for accelerating ions incident on the processing body and an yttria on the inner wall of the processing chamber,
A plasma processing apparatus comprising a fluorination detection sensor for detecting the degree of fluorination of an inner wall on a processing chamber wall. The plasma processing apparatus according to claim 1,
The fluorination detection sensor uses an FT-IR method, and the detection unit surface is coated with yttria having a thickness of 10 nm to 10 μm. A processing chamber, a high-frequency power for plasma generation, a processing gas supply function for supplying a processing gas, an exhaust means for decompressing the processing chamber, a stage for placing a target object, In a plasma processing apparatus having a wafer bias power source for accelerating ions incident on a processing body and an inner wall material obtained by coating a metal base material with an yttria film,
2. A plasma processing apparatus according to claim 1, wherein a part constituting the processing chamber wall is divided into a plurality of parts, and the processing chamber wall is composed of a metal base material coated with yttria and a quartz part.   4. The plasma processing apparatus according to claim 3, wherein the quartz part is installed at a height position where the plasma density is high. A processing chamber, a high-frequency power for plasma generation, a processing gas supply function for supplying a processing gas, an exhaust means for decompressing the processing chamber, a stage for placing a target object, In a plasma processing apparatus having a wafer bias power source for accelerating ions incident on a processing body and an inner wall material made of yttria,
2. A plasma processing apparatus according to claim 1, wherein a part constituting the inner wall of the processing chamber is divided into a plurality of parts, and the inner wall of the processing chamber is made up of yttria parts and conductive parts.   6. The plasma processing apparatus according to claim 5, wherein SiC is used for the conductive component.   2. The plasma processing apparatus according to claim 1, wherein the fluorination detection sensor monitors the degree of fluorination of yttria and determines the end point of cleaning when the fluorination degree is equal to or less than a predetermined value. A plasma processing apparatus.

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