JP2012156275A - Plasma processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing apparatus which achieves an improved throughput by adjustment of the temperature of an inner side wall of a process chamber.SOLUTION: A plasma processing apparatus comprises: a vacuum vessel; a process chamber in the vacuum vessel where plasma is generated; a sample holder which is placed in a lower portion of the process chamber, and on which a sample is set; a dielectric disk member which is disposed in an upper portion of the vacuum vessel, covers an upper portion of the process chamber, and partitions the inside of the process chamber in an air tight manner; a cylindrical cavity which is disposed above the disk member, and into which an electric field supplied to the inside of the process chamber through the disk member is introduced; a wave guide which is jointed to a center portion of the cavity, and through the inside of which the electric field runs; a first supply port which is disposed on the side of the outer periphery of a joint of the cavity and the wave guide, and supplies a given high-temperature gas from the periphery toward the center inside the cavity; a second supply port which is disposed on the wave guide and to which a low-temperature gas is supplied; and an exhaust port which is disposed on the wave guide, and through which the gas supplied from the first and second supply ports and flowing through the inside is exhausted.

Description

  The present invention relates to a plasma processing apparatus for processing a sample such as a semiconductor wafer disposed in a processing chamber using plasma formed in the processing chamber using a microwave.

  A plasma is generated by causing a gas discharge by using a reaction gas and microwaves introduced into a container whose pressure is reduced near a conventional vacuum, and the substrate surface is irradiated with the plasma to perform processing such as etching and thin film formation. In plasma processing equipment, chemical active species and ions generated by processing gas molecules and plasma, and reaction products generated by reaction with the processing chamber wall and substrate to be processed are caused by temperature fluctuations in the processing chamber wall. It has been found that the amount of adsorption to the inner wall of the processing chamber and the content in the plasma change, and the state of the processing chamber changes, thereby affecting the etching characteristics.

  Conventionally, the temperature control of the plasma-resistant wall is stabilized by the temperature rise by the plasma. However, during mass production, the arrival time of lots is irregular, and the plasma wall surface temperature before wafer processing starts is different each time. However, there is no index for determining the optimum plasma heating time, and discharge is performed for a certain time each time. The temperature was raised. As a result, the first wafer processing temperature is different from the n-th wafer processing temperature, and a decrease in yield due to a change in processing characteristics and a long discharge time for plasma temperature increase are problematic. It was.

  In order to control the temperature of the plasma-resistant wall against this problem, the wall of the fluid medium whose temperature is adjusted by a temperature controller such as a chiller arranged outside the processing vessel is formed to surround the processing chamber inside the vessel. A technique for adjusting the temperature of the side wall surface in the processing chamber by a method of controlling the temperature by introducing into a member to be controlled and a method of adjusting the temperature by arranging a heater on the outer periphery or inside of the wall member has been known. As such conventional techniques, those disclosed in Japanese Patent Application Laid-Open No. 2002-319577 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2008-034885 (Patent Document 2) are known.

  In Patent Document 1, a passage through which a fluid (heat medium) such as a gas or a liquid whose temperature is adjusted passes through a member that forms a side wall facing the plasma surrounding a space in which plasma in the processing chamber is formed. And a technique for adjusting the temperature of the processing chamber wall of the side wall during the processing of a sample such as a semiconductor wafer. Further, in Patent Document 2, heat transfer is performed between a wall of a vacuum vessel in which a heater is arranged on the outer periphery and a member constituting a side wall facing the plasma surrounding the outer periphery of a space in which plasma is formed in the processing chamber. Technology is disclosed that improves the heat transfer between a heater and a member constituting the processing chamber side wall by supplying a reactive gas to improve the responsiveness and accuracy of adjusting the temperature of the processing chamber wall.

JP 2002-319577 A JP 2008-034885 A

  In the above-described prior art, the following points have not been sufficiently considered, causing problems. That is, in the above-described conventional technology, a plate-like member in which holes are provided to introduce a processing gas from above a member constituting the top surface of the processing chamber, particularly a sample stage or a sample placed thereon. The point of adjusting the temperature of the so-called shower plate has not been sufficiently considered.

  In Patent Documents 1 and 2, by adjusting the temperature of the inner wall of the processing chamber to a predetermined range during processing, the interaction between the surface of the inner wall and the plasma in the processing chamber is made desired, Although the purpose is to adjust the amount and distribution of the formed product attached to the inner wall, the shower plate is supplied with electric power to form a bias potential, and the product on the surface of the shower plate is The charged particles in the plasma caused by the bias potential are removed by colliding with the shower plate, and it has not been considered that the temperature is as expected. For this reason, in the plasma processing apparatus in which the adhesion of the product due to the bias potential cannot be adjusted or becomes insufficient, the configuration for adjusting the interaction between the inner wall of the processing chamber and the plasma is not considered, Insufficient consideration has been given to the possibility that at least a part of the temperature of the inner wall of the processing chamber becomes unstable and the processing yield and throughput of the sample may be impaired.

  In the above prior art, the shower plate, which is one of the members constituting the inner wall of the processing chamber, is arranged above and covers the sample, and its temperature is a characteristic such as the sample etching speed and processing accuracy. In spite of having a great influence on the temperature, active temperature control was not performed. In particular, in the plasma processing apparatus disclosed in Patent Document 2 that forms plasma by so-called ECR by the interaction between an electric field and a magnetic field by a microwave, a plate member made of a dielectric such as quartz having a large heat capacity is used as a vacuum vessel. It is generally configured to cover the upper side of the processing chamber, and a shower plate is arranged in the vicinity of the lower side of the lower surface of the processing chamber. Since the quartz plate member does not directly contact the plasma, There is a member that has a large heat capacity and is in contact with the atmosphere side directly above the shower plate that is the object of adjustment, which regulates the temperature of the inner wall, and even if the shower plate is heated by plasma, it is stabilized at a predetermined temperature. Therefore, a long discharge is required, resulting in a problem that the throughput is lowered.

  An object of the present invention is to provide a plasma processing apparatus that improves the throughput by adjusting the temperature of the inner wall of the processing chamber.

  The above-described object is to provide a cylindrical processing chamber that is arranged inside the vacuum vessel and in which plasma is formed inside, a sample stage that is arranged in the lower part of the processing chamber and on which the sample is arranged, and an upper part of the vacuum vessel. And a dielectric disk member that covers the top of the processing chamber and hermetically divides the inside of the processing chamber, and is disposed above the disk member and passes through the disk member to enter the processing chamber. A cylindrical cavity into which an electric field to be supplied is introduced, and a waveguide extending above and connected to the central portion of the cavity, in which the electric field propagates, and the cavity And a first supply port for supplying a gas adjusted to a predetermined temperature from the outer periphery inside the cavity toward the center, disposed on the outer peripheral side of the coupling portion between the waveguide and the waveguide, and disposed in the waveguide A second supply port to which a gas having a temperature lower than the predetermined temperature is supplied; The gas is disposed in the tube flows inside is supplied from the first and second supply ports is achieved by a plasma processing apparatus provided with an outlet to be discharged.

  Further, the second supply port is disposed in the middle of the connection portion between the waveguide and the central portion of the cavity and the exhaust port, and the temperature of the exhausted gas is made lower than the temperature inside the cavity. Is achieved.

  Furthermore, this is achieved by arranging the discharge port between the connecting portion between the waveguide and the central portion of the cavity and the second supply port.

  Furthermore, the waveguide has a cylindrical waveguide extending above the central portion of the cavity and one end of the waveguide connected to the cylindrical waveguide and extends in the horizontal direction. This is achieved by including a rectangular waveguide in which the means for generating the electric field is disposed, and the discharge port is disposed at a connection portion between the circular waveguide and the rectangular waveguide.

  Furthermore, the temperature or amount of the gas supplied from the first supply port based on the output from the detector that detects the temperature of the disk member, or the temperature of the gas supplied from the second supply port Or by providing a controller to adjust either the amount.

It is a longitudinal cross-sectional view which shows the outline of a structure of the plasma processing apparatus concerning the Example of this invention. It is a longitudinal cross-sectional view which expands and shows the structure of the upper part in the Example shown in FIG. It is a longitudinal cross-sectional view which expands and shows the outline of the structure of the modification of the Example shown in FIG. It is a longitudinal cross-sectional view which expands and shows the outline of the structure of the other modification of the Example shown in FIG. It is a top view which shows typically the structure of the exhaust port of the waveguide which concerns on the Example shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

〔Example〕
FIG. 1 is a longitudinal sectional view showing an outline of a configuration of a plasma processing apparatus according to an embodiment of the present invention. In this embodiment, the plasma processing apparatus is roughly divided into three parts, and includes a plasma forming part, a vacuum vessel, and an exhaust part from above.

  In this embodiment, the plasma forming unit is configured to supply an electric field and a magnetic field for forming plasma in the processing chamber, and the microwave source 101 for forming the electric field and the microwave source 101 are arranged at one end thereof. The waveguide 103, which is a pipe line through which the electric field in the microwave band formed by the microwave source propagates, and the waveguide 103 is bent at the other end and the axis of the pipe is bent from the horizontal direction to the vertical direction. The cavity resonance part 104 is connected to the other end part, and the electric field resonates at a predetermined frequency, mode, and intensity in the internal space on the cylindrical shape, and is disposed on the outer periphery of the waveguide 103 and the cavity resonance part 104. And a solenoid coil 105 that forms a magnetic field for forming plasma.

  The microwave source 101 of the present embodiment is grounded via a power source that forms microwave band power. Further, an automatic matching machine 102 is provided adjacent to this, the load impedance is adjusted, and the reflected wave is automatically suppressed.

  As the microwave source of this embodiment, a magnetron having an oscillation frequency of 2.45 GHz is used. The waveguide 103 has a horizontal section with a horizontal axis, and the upper section connected to the upper part of the cavity resonator 104 has a circular section. The electric field of the microwave propagated through the inside has a predetermined mode and propagates from above to the cylindrical cavity resonator 104. In this embodiment, the inside of the waveguide 103 and the cavity resonator 104 is set to a pressure equivalent to the surrounding atmosphere, that is, a so-called atmospheric pressure.

  The solenoid coil 105 is arranged on the outer periphery of a vacuum vessel arranged below the cavity resonance unit 104 and surrounds the outer periphery of a space (discharge unit) where plasma is formed above the processing chamber inside the vacuum vessel. The two-stage ring-shaped electromagnet that surrounds the side of the processing chamber and the ring-shaped electromagnet that surrounds the waveguide 103 above the cavity resonator 104 are used, and by changing the current that flows through this electromagnet, The distribution of the static magnetic field in the processing chamber can be controlled.

  In the vacuum vessel, below the cavity resonance portion 104, there is a dielectric window 111 that constitutes the upper portion of the vacuum vessel and hermetically seals the inside and outside of the vacuum vessel and through which the electric field is transmitted toward the plasma processing chamber 110. The bottom surface of the space inside the cavity resonance unit 104 is configured and arranged. Below that, a shower plate 112 is arranged through a gap with this, and the lower surface of the shower plate 112 constitutes the upper surface of the plasma processing chamber 110 and faces the plasma P formed therein.

  A gap 117 between the shower plate 112 and the dielectric window 111 is a space 117 into which a processing gas is introduced, and the processing gas diffused in this space is a sample of the sample stage 118 having a cylindrical shape of the shower plate 112. Is introduced into the plasma processing chamber 110 toward the sample stage 118 through a plurality of through holes arranged at equal intervals above the upper surface of the substrate. The plasma processing chamber 110 is configured in a cylindrical shape so that a uniform plasma is formed on a wafer 160 having a circular shape, which is placed on the mounting surface constituting the upper surface of the sample stage 118 and subjected to the plasma processing. Similarly, the dielectric window 111, the shower plate 112, and the cylindrical sample stage 118 have a circular cross section and a mounting surface, and the central axes thereof are arranged so as to coincide with the vertical direction. ing. That is, they are arranged and assembled so as to be coaxial in the vertical direction.

  A cylindrical sample stage 118 is disposed below the shower plate 112 in the plasma processing chamber 110 and below the space in which the plasma P is formed, with the shower plate 112 facing the mounting surface on the upper surface thereof. . A lower electrode 120 having a disk shape or a cylindrical shape made of a conductor is disposed therein, and is electrically connected to an RF power source 121 that generates high-frequency (Raidio Frequency) power via a matching unit 122. The high frequency supplied from the RF power source 121 to the lower electrode 120 generates a bias potential with the plasma P above the wafer 160 placed on the mounting surface, and the plasma P has an internal potential due to the potential difference with the plasma P. The charged particles are attracted to and collide with the surface of the wafer 160 to promote plasma processing.

  In this embodiment, the sample stage 118 is held inside and below the plasma processing chamber 110 via a space as described below, and is a circular shape disposed directly below the sample stage 118 via the lower space. Above the exhaust port 150, it is supported in a hollow space by beams connected at equal angles around the central axis. The space between the beams is a space that connects and communicates a space where the plasma P is formed above the sample stage 118 and a space facing the lower exhaust port 150, and is introduced above the sample stage 118. Particles such as the processing gas, plasma P, and products formed during the processing flow through this space to the lower space and flow out of the plasma processing chamber 110 from the exhaust port 150.

  The processing gas introduced into the plasma processing chamber 110 flows from the gas source 130 which is disposed outside the vacuum vessel and is connected to the dielectric chamber 111 and the shower through the inside. It is disposed between the plate 112 and the upper surface thereof is introduced into the space 117 surrounded by the gas introduction ring 113 which faces or contacts the lower surface of the outer peripheral edge of the dielectric window 111 via the seal member. This gas diffuses in the space 117 over the entire region where the through hole of the shower plate 112 is disposed, and flows downward as a reactive gas for plasma formation from the through hole. The flow rate and speed of the processing gas are adjusted by the gas supply device 131, and the gas supply starts or ends when the gas valve 132 opens and closes the pipeline.

  As described above, the upper part of the vacuum vessel is configured to include the disk-shaped dielectric window 111 and the ring-shaped gas introduction ring 113 from the microwave introduction direction, and a metal discharge is provided below the gas introduction ring 113. A block wall 114, an electrode outer peripheral ring 115, and a lower chamber wall 116 are provided. These have a cylindrical shape, and each member is hermetically sealed inside and outside by a sealing member such as an O-ring, and the inside processing chamber is sealed from the outside.

  The exhaust unit connected to the lower part of the vacuum vessel is located below the exhaust port 150 and below the bottom of the lower chamber wall and directly below the sample stage 118. Particles from above flowing into the space below the sample stage 118 flow into the inlet of an exhaust pump such as a TMP (turbo molecular pump) 152 disposed further downward through the exhaust port 150 and are exhausted. It is discharged to the outdoor part of the building where the plasma processing apparatus 100 is installed through a roughing pump (not shown) arranged on the downstream side (arrow). The flow rate and speed of the exhaust from the plasma processing chamber 110 are the direction of the flow of exhaust disposed between the inlet of the TMP 152 and the exhaust port 150 (in this embodiment, the vertical direction passing through the center of the circular exhaust port 150). Is adjusted by a movable valve 151 that rotates around an axis in a direction (horizontal direction in this embodiment) intersecting with the direction of the axis of the exhaust gas and changes the cross-sectional area of the passage through which the exhaust flows. The pressure inside the plasma processing chamber 110 is adjusted by the balance between the cross-sectional area of the exhaust passage by the operation of the movable valve 151 and the flow rate or speed of the processing gas introduced from the through hole of the shower plate 112 adjusted by the gas supply device 131. Adjusted. Note that the vertical axis around which the blade rotates around the inside of the TMP 152 is arranged to coincide with the vertical axis of the sample stage 118.

  When plasma processing is performed on the wafer 160 in the plasma processing apparatus 100 as described above, the unprocessed wafer 160 is taken out from the inside of the cassette placed on the cassette table disposed outside by a transfer device (not shown). The sample is transferred into the plasma processing chamber 110 and transferred to the sample stage 118 above the sample stage 118. When the transfer device exits the plasma processing chamber 110 and is closed by a valve (not shown), the wafer 160 is placed on the mounting surface and is placed inside the dielectric film that forms the mounting surface. It is electrostatically attracted and held on the mounting surface by static electricity generated by the electric power supplied to the electroadsorption electrode.

  A gas for heat transfer is introduced between the wafer 160 and the mounting surface, and a processing gas is introduced into the plasma processing chamber 110 through the through hole of the shower plate 112. Further, during the above operation, particles such as gas in the plasma processing chamber 110 are exhausted from the exhaust port 150, and the flow rate and speed of the exhaust gas and the flow rate and speed of the supplied processing gas are balanced. Thus, the inside of the plasma processing chamber 110 is brought to a predetermined pressure. In this state, the inside of the plasma processing chamber 110 is shut off from the outside except for a part of the exhaust port 150, the through hole, and the like, and is hermetically sealed.

  Next, the microwave oscillated from the microwave source 101 propagates through the waveguide 103 and is introduced into the cavity resonance unit 104. The microwave introduced in the cavity resonator 104 is distributed according to a predetermined mode suitable for plasma processing, and the dielectric such as quartz constituting the bottom surface of the cylindrical space in the cavity resonator 104 is formed. It is introduced into the plasma processing chamber 110 through the dielectric window 111 made of a body and the shower plate 112 made of a dielectric material such as quartz. In addition, a magnetic field generated by the solenoid coil 105 is also introduced into the plasma processing chamber 110.

  The reactive gas is excited by the ECR (electron cyclotron resonance) generated by the interaction between the electric field by the microwave and the magnetic field by the solenoid coil 105, and the plasma P is formed. ECR selects electrons by injecting into the plasma P a microwave with an appropriate frequency corresponding to the rotation period when the electrons move while rotating along the magnetic field lines of the magnetic field generated by the solenoid coil 105. This is an effective heating method for the plasma P. Further, by using the static magnetic field, the position where ECR is generated can be controlled by changing the distribution of the static magnetic field, and the plasma generation region can be controlled. Further, it is known that the diffusion of the plasma P is suppressed in the direction perpendicular to the lines of magnetic force, and there is an advantage that the diffusion of the plasma P can be controlled and the loss of the plasma can be reduced.

  Further, a high frequency of 400 kHz is applied from the RF power source 121 connected to the lower electrode 120 to the lower electrode 120 through the matching unit 122, so that a bias potential is formed above the upper surface of the wafer 160 placed on the sample stage 118. Is formed, and charged particles such as ions are drawn from the plasma P in the direction of the surface of the wafer 160 according to the potential difference with the plasma P, and the processing of the wafer 160 is started.

  The processing of the wafer 160 by the plasma P has reached an intended state (for example, an end point has been reached such as reaching the interface with the film below the film to be processed, reaching a groove of a predetermined depth, etc.) Is detected, the plasma P is extinguished and the application of the high frequency power to the lower electrode 120 is stopped. Contrary to the case of carrying in the wafer 160, the wafer 160 is transferred from the sample stage 118 to the vacuum transfer device and returned to the original position of the original cassette, and the operation of the wafer by the plasma processing apparatus 100 is completed. .

  Each part of the plasma processing apparatus of the present embodiment is connected via a communication means to a control device including an arithmetic device, a storage device, and a signal input / output device (not shown), and an output detected by a sensor between the control device. The signal and the signal for instructing the operation from the arithmetic unit are transmitted and received, and the timing and the operation amount are adjusted so as to operate in an appropriate sequence.

  In this embodiment, in order to adjust the temperature of the surfaces of the dielectric window 111 and the shower plate 112 to a predetermined range, an air heater 170 including a heater that heats external air above the cavity resonance unit 104, and A radiation thermometer 173 having a sensor for detecting the temperature of the dielectric window 111 or the shower plate 112 is disposed. The air heater 170 adjusts a gas line 172 for introducing atmospheric gas outside the plasma processing apparatus 100, for example, air in a building such as a clean room where the plasma processing apparatus 100 is installed, at the same temperature, and the flow rate and speed of the introduction. Connected to the controller 171. Further, the radiation thermometer 173 detects the temperature of the dielectric window 111, and the controller 171 turns on or off the air heater 170 based on the temperature value detected from the output signal from the radiation thermometer 173. The temperature of the air to be introduced is adjusted so as to be within a desired range set by the user by changing the voltage to increase or decrease the heating.

  The air, which is the external atmosphere heated from the room temperature in the building by the air heater 170 and raised in temperature, is introduced into the resonance space inside the cavity resonator 104 and between the dielectric window 111 constituting the bottom surface thereof. Heat this with heat exchange. Further, when air is introduced as it is without being heated by the air heater 170, the dielectric window 111 heated by receiving heat transfer from the plasma P during the processing can be cooled.

  Such a configuration will be described in detail with reference to FIG. FIG. 2 is an enlarged longitudinal sectional view showing the structure of the upper part in the embodiment shown in FIG. In this figure, only the upper part of the plasma processing apparatus of the embodiment shown in FIG. 1, in particular, the upper part including the gas introduction ring 113 is enlarged and extracted.

  As shown in FIG. 2, the air introduced from the air heaters 170 disposed at a plurality of positions on the outer peripheral side portion of the upper portion of the cavity resonance unit 104, particularly at a plurality of positions at equal angles in the circumferential direction of the center of the dielectric window 111, The portion of the waveguide 103 that flows toward the center side of the cavity resonator 104 after coming into contact with the dielectric window 111 and is connected to the center of the upper portion of the cavity resonator 104 and whose axis of the tube is arranged vertically. It enters the inside of the waveguide 103 from the opening at the lower end (referred to as the vertical portion) (arrow in the figure). Further, it passes through the interior of the vertical portion, and is discharged to the outside of the waveguide 103 through an exhaust port 140 disposed at the upper portion of the vertical portion of the waveguide 103 in the vertical direction. The exhaust port 140 is provided at an end portion (the other end portion) opposite to the one end portion where the microwave source 101 is disposed in a portion where the tube axis of the waveguide 103 is disposed in the horizontal direction (the same horizontal portion). Has been placed.

  On the other hand, the microwave source 101 and the automatic matching machine 102 such as a power source and a stub tuner are arranged on one end side of the horizontal portion of the waveguide 103, so that the air heated by the air heater 170 is placed at the place where these are installed. It is necessary to devise measures to prevent these malfunctions and abnormalities due to inflowing and heating them, and thus heating beyond the conditions under which these normal operations are possible. Further, since the inside of the waveguide 103 is a passage through which a microwave electric field passes, in order to prevent the air flow and exhaust from changing the characteristics of the plasma P formed in the plasma processing chamber 110, There is also a need for a configuration that suppresses the occurrence of trouble in the progress of the microwave electric field passing through the waveguide 103.

  In this figure, in this embodiment, the cooling unit 201 is arranged on the side wall of the vertical portion of the waveguide 103. The cooling unit 201 is connected to and connected to the gas line 172, and air, which is a gas having the same temperature as the atmosphere introduced from the gas line 172, is introduced into the waveguide 103 and rises in the vertical portion of the waveguide 103. The temperature of the gas from the cavity resonance part 104 is reduced. The cooling unit 201 is opened in a ring-shaped gas passage surrounding the outer periphery of the pipe of the cylindrical vertical portion of the waveguide 103, and an inner side wall of the ring-shaped gas passage and the vertical portion of the waveguide 103. A passage communicating with an inlet such as a slit is provided.

  The atmospheric gas introduced into the ring-shaped gas passage flows through the interior and is introduced upward from the opening into the interior of the vertical portion of the waveguide 103 through the communicating passage (the white outline shown in FIG. 2). Arrow). Furthermore, the temperature of the air flowing through the waveguide 103 is mixed with the high-temperature air flowing in from the lower cavity resonator 104 and rising upward, and the temperature of the air flowing in the waveguide 103 is higher than that flowing in the cavity resonator 104. Reduced. Further, the cooling unit 201 is a means for cooling the atmospheric gas in the ring-shaped gas passage, for example, a configuration in which the atmosphere is introduced into the outer wall of the ring-shaped gas passage for heat exchange and cooling, and a pipe through which the refrigerant circulates. It may be in thermal contact with the road.

  Further, the cooling unit 201 is synchronized with the ON / OFF of the air heater so that the cooled air is introduced into the waveguide 103 only when heated air is introduced by the controller 171 installed outside, and when not heated. It may be adjusted to reduce or stop the introduction of the atmosphere into the opening or communicating passage. With such a configuration, dew condensation inside the waveguide 103 due to the introduction of the low-temperature gas into the waveguide 103 is suppressed.

  With this configuration, in this embodiment, the dielectric window 111 is heated and its temperature is adjusted within a predetermined range, and the ambient gas passing through the waveguide 103 is cooled to a lower temperature from the cooling unit 201. By mixing the gas, the temperature of the gas passing through the inside of the waveguide 103 flows into the microwave source 101 or the automatic matching machine 102 disposed on one end side of the horizontal portion of the waveguide 103. However, even if it reaches, the temperature is lowered to a temperature that does not hinder these operations. Further, by introducing a lower temperature gas toward the upper side of the waveguide 103 (upstream side of the gas flow direction or the electric field propagation direction), the flow of the heated air inside the cavity resonance unit 104 is blocked. In addition, the temperature of the air passing through the inside of the waveguide 103 is adjusted to a desired range by suppressing the low temperature gas from reaching the dielectric window 111.

  FIG. 3 is an enlarged longitudinal sectional view showing a schematic configuration of a modification of the embodiment shown in FIG. Also in this figure, only the upper part of the plasma processing apparatus of the embodiment shown in FIG.

  In the modification shown in this figure, the exhaust port 175 has an exhaust device 302 such as a fan disposed downstream of the exhaust flow. The gas exhausted from the exhaust port 140 is further exhausted through an exhaust path to the outside of the plasma processing apparatus 100 or outside a building such as a clean room where the plasma processing apparatus 100 is installed by an exhaust device 302 such as a fan.

  Further, a gas supply port 301 is disposed further upstream of the microwave source at one end of the horizontal portion of the waveguide 103 in the electric field propagation direction, and the waveguide is connected to the waveguide from the gas supply port 301 by the operation of the exhaust device 302. A flow is generated in which the gas introduced into the interior of 103 is directed toward the exhaust port 175 and flows out from the exhaust port 175 (hatched arrows in the figure). By this flow, the flow rate and speed of the gas that heats the dielectric window 111 and rises in the vertical portion of the waveguide 103 and passes through the interior toward the microwave source 101 and the automatic matching machine 102 are reduced.

  The gas supply port 301 is connected to a gas line 303 for introducing air, or has an opening for introducing external air. The opening degree is used by an operator or an operator of the plasma processing apparatus 100. It may be possible for a person to input a command signal to a control device or controller 171 (not shown) so as to be variably adjusted and set. Such adjustment of the flow rate or opening area of the introduced gas is introduced from above into the cavity resonator 104 through the gas line 303 and the air heater 170 which are adjusted to achieve the target temperature of the dielectric window 111. The flow rate or speed of the gas discharged from the vertical portion of the waveguide 103 through the exhaust port 175, that is, the target value for adjusting the temperature of the dielectric window 111 or the shower plate 112 is increased or decreased. The temperature of the dielectric window 111 or the shower plate 112 is also adjusted by adjusting the flow rate or speed of the gas introduced from the gas supply port 301 into the horizontal portion of the waveguide 103 and discharged from the exhaust port 175. .

  4 is an enlarged longitudinal sectional view showing the outline of the configuration of another modification of the embodiment shown in FIG. Also in this figure, only the upper part of the plasma processing apparatus of the embodiment shown in FIG.

  In this modification, a gas supply port 401 connected to the gas line 172 is arranged at the upper part or the upper end part of the vertical part of the waveguide 103. From the gas supply port 401, a gas having a temperature equal to the atmospheric gas or a gas cooled by a cooling means (not shown) is introduced toward the lower dielectric window 111.

  Further, an exhaust passage 405 having a gap disposed in a cylindrical shape is provided surrounding the outer peripheral wall of the vertical portion of the waveguide 103, and an exhaust communicating with the outside of the plasma processing apparatus 100 is provided at the upper end of the gap. A mouth 402 is arranged. Further, the lower end of the exhaust passage 405 communicates with an opening 404 disposed facing the upper end of the cylindrical space inside the cavity resonance unit 104, and is introduced from an air heater 170 disposed on the outer peripheral side of the opening 404. The heated gas flows toward the center while heating the dielectric window 111 to adjust the temperature, and is connected to the lower end portion of the vertical portion of the waveguide 103 disposed at the upper center of the cavity resonance portion 104. The gas flows out of the upper opening 402 through the exhaust passage 405 from the opening 404 formed by a plurality of circular gaps that can be regarded as a circle or a circle arranged around the outer periphery of the opening (arrow in the figure).

  A cooling pipe 403 through which a fluid for cooling the gas passing through the exhaust passage 405 flows is disposed inside or on the outer peripheral wall of the cylindrical metal member surrounding the outer periphery of the exhaust passage 405. In the present modification, the vertical portion of the gas introduced from the air heater 170 is raised by the flow of the gas introduced downward from the gas supply port 401 at the upper part of the vertical portion of the waveguide 103, and the microwave source The flow toward the direction 101 or the automatic aligner 102 is reduced, and high temperature gas reaches them and is prevented from malfunctioning or stopping.

  In the above embodiment, openings such as the exhaust ports 140 and 175 or the gas supply ports 301 and 401 are arranged on the waveguide 103. In particular, in the above-described embodiment, the projection surface of the pipe portion which is the upper end portion of the vertical portion of the waveguide 103 or the upper surface of the connecting portion between the horizontal portion and the vertical portion and immediately above the pipe portion of the vertical portion in the axial direction. It is arranged on the upper surface of the waveguide 103 located inside. In this case, the opening faces the opening of the connection portion between the cavity resonance portion 104 and the waveguide and the dielectric window 111 below the opening through the vertical portion, and these openings exhaust the gas inside. In addition, the flow is hardly suppressed to supply air to the inside, and even when the opening is adjusted by the controller 171 or a control device (not shown), the accuracy and responsiveness are reduced and high performance is reduced. Can be earned. Moreover, in order not to inhibit the propagation of the microwave passing through the inside of the waveguide 103, and to sufficiently attenuate the microwave passing through the opening, it is necessary to consider the installation location and shape.

  The cross-sectional shape of the waveguide 103 is perpendicular to the propagation direction, and the cross-section is changed from a horizontal shape in the propagation direction to a circular shape in the vertical portion. In order to suppress the influence on the electric field distribution of the microwave passing through the inside, the opening is arranged in this conversion part, that is, a connecting part or a connecting part between the horizontal part and the vertical part. It is more effective to arrange at a position closer to the center of the axis of the waveguide of the waveguide 103.

  FIG. 5 is a plan view schematically showing the configuration of the exhaust port of the waveguide according to the embodiment shown in FIG. In particular, the shape of the opening of the exhaust port 140 or the gas supply ports 301 and 401 in the above-described embodiment or modification is shown. The shapes of these openings are configured so as to inhibit the flow of current passing through the surface of the waveguide 103 and to suppress disturbance due to the internal electric field passing through these openings.

  In the example shown in FIG. 5, the slit type exhaust port opening 501 shown in FIG. 5A and the punch plate type exhaust port opening 502 shown in FIG. 5B are shown. In the slit-type exhaust opening 501 shown in FIG. 5A, the opening has a rectangular shape, and the long side of the opening of each slit is arranged in parallel to the traveling direction of the electric field. The dimension is a quarter of the wavelength λg of the electric field passing through the waveguide 103, and the short side dimension is smaller than that of the long side. This suppresses the inhibition of the propagation of the microwave electric field, and effectively attenuates the microwave electric field passing through the exhaust opening 501. Also, in the punch plate type exhaust port opening 502 of FIG. 5B, a plurality of circular or elliptical openings are spaced within a predetermined radius from the center of the center of the circular member with a predetermined interval. It is arranged in the region, and it is effective to make the diameter of each of the plurality of openings smaller.

  Furthermore, in these embodiments, it is effective to prevent the leakage of microwaves by giving a dimension in the thickness direction of the opening and arranging a conductive mesh such as expanded metal in the opening. is there. Further, as described above, the exhaust port 140 has a structure in which the opening degree can be freely changed, and the exhaust amount to the outside can be controlled by controlling the opening degree.

  According to the above-described embodiment, the temperature of the dielectric plate 111 adjacent to the shower plate 112 or the shower plate 112 that affects the processing or plasma characteristics when the wafer 160 is processed by forming plasma is adjusted. During processing of a plurality of wafers 160 of an arbitrary lot, fluctuations in processing results and processing characteristics between the plurality of wafers 160 due to temperature fluctuations on the inner wall surface of the plasma processing chamber 110 are reduced, and processing efficiency and Yield is improved.

101 Microwave Source 102 Automatic Matching Machine 103 Waveguide 104 Cavity Resonator 105 Solenoid Coil 110 Plasma Processing Chamber 111 Dielectric Window 112 Shower Plate 113 Gas Introducing Ring 114 Discharge Block Wall 115 Electrode Outer Ring 116 Lower Chamber Wall 118 Sample Stand 120 Lower Electrode 121 RF power supply 122 Matching unit 130 Gas source 131 Gas supply device 132 Gas valve 140, 150, 402 Exhaust port 151 Movable valve 152 TMP
160 Wafer 170 Air heater 171 Controller 172 Gas line 173 Radiation thermometer 201 Cooling unit 301 Gas supply port 302 Exhaust device 401 Gas supply port 403 Cooling pipelines 501 and 502 Exhaust port opening

Claims (5)

  A cylindrical processing chamber that is arranged inside the vacuum vessel and in which plasma is formed inside, a sample stage that is arranged in the lower part of the processing chamber and on which the sample is arranged, and an upper part of the vacuum vessel that is arranged in the processing A dielectric disk member that covers the upper portion of the chamber and hermetically divides the inside of the processing chamber, and an electric field that is disposed above the disk member and passes through the disk member and is supplied into the processing chamber. A cylindrical cavity to be introduced, and a waveguide extending above and connected to a central portion of the cavity, in which the electric field propagates, the cavity, and the waveguide And a first supply port for supplying a gas adjusted to a predetermined temperature from the outer periphery inside the cavity toward the center, and disposed on the outer peripheral side of the connecting portion, and disposed on the waveguide from the predetermined temperature. A second supply port to which a low temperature gas is supplied, and disposed in the waveguide. Serial plasma processing apparatus in which the gas flowing therethrough is supplied and a discharge port which is discharged from the first and second supply ports.   2. The plasma processing apparatus according to claim 1, wherein the second supply port is disposed between a connection portion between the waveguide and a central portion of the cavity and the discharge port, and A plasma processing apparatus, wherein the temperature is lower than the temperature inside the cavity.   2. The plasma processing apparatus according to claim 1, wherein the discharge port is disposed between a connection portion between the waveguide and a central portion of the cavity and the second supply port.   4. The plasma processing apparatus according to claim 1, wherein the waveguide includes a cylindrical waveguide extending above a central portion of the cavity and one end portion of the waveguide. A rectangular waveguide connected to the tube and extending in the horizontal direction and having the means for generating the electric field disposed at the other end, and the discharge port is formed between the circular waveguide and the rectangular waveguide. A plasma processing apparatus disposed in the connecting portion.   5. The plasma processing apparatus according to claim 1, wherein the temperature or amount of gas supplied from the first supply port based on an output from a detector that detects the temperature of the disk member. Or the plasma processing apparatus provided with the controller which adjusts either the temperature or quantity of the said gas supplied from said 2nd supply port.

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