JP2005093843A - Plasma treatment device and upper electrode unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform highly accurate positional control by using an air pressure actuator. <P>SOLUTION: This plasma treatment device is provided with an upper electrode arranged in a chamber 102 oppositely to a wafer W in the chamber 102, a sliding/supporting member 204 for supporting the upper electrode 120 so as to freely slide the upper electrode 120 in one direction by means of a sliding mechanism 210, an air pressure cylinder 220 having a rod 202 connected to the sliding/supporting member 204, and a drive control means 300 (an air pressure circuit 310 and a control means 400) for controlling the drive of the air pressure cylinder 220. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plasma processing apparatus for plasma processing a glass substrate for a flat substrate (FPD) such as a liquid crystal display (LCD), that is, an FPD substrate such as an LCD substrate, as well as a semiconductor wafer. Relates to a plasma processing apparatus and an upper electrode unit capable of driving and controlling members such as electrodes provided in the plasma processing apparatus to desired positions.

  Generally, in each process for manufacturing a semiconductor device, an LCD substrate, and the like, a plasma processing apparatus that performs plasma processing on an object to be processed, such as a semiconductor wafer (hereinafter simply referred to as a wafer), an LCD substrate, etc. is disposed in the processing apparatus. When a member, for example, an electrode, is linearly moved and driven and controlled to a desired position, follow-up control is performed using a motor such as a servo motor or a stepping motor as an actuator.

  In such a structure using a motor as an actuator, in order to convert the rotation of the motor into a linear motion, a solid structure that forms a power transmission mechanism such as a pulley, a gear, a belt, or a chain is required. There was a problem of increasing the size. In addition, vibration and noise are generated by the rotational movement of the motor and the power transmission mechanism, which may affect the process processing result of the wafer. In addition, the gears and chains that make up the power transmission mechanism are consumables, which necessitates regular maintenance.

  In this regard, it is conceivable to use a hydraulic actuator instead of a motor as the actuator. However, the hydraulic actuator is difficult to pipe, and there is a problem that oil leakage may cause clean room contamination. It is not suitable as an actuator for use in a processing apparatus.

  It is also conceivable to use a pneumatic actuator as the actuator. If it is a pneumatic actuator, there is no risk of oil leakage and the clean room is not contaminated. In addition, pneumatic actuators have the advantage of being combined into a lightweight, high-power and compact structure. For this reason, also in the field of plasma processing apparatuses, it is used for a wafer cassette lifting mechanism (see, for example, Patent Document 1) and a gate opening / closing mechanism (see, for example, Patent Document 2) provided at a wafer carry-in / out port of a processing chamber.

JP 2001-35897 A JP-A-10-209245

  However, when a pneumatic actuator is used as an actuator to drive and control a member provided in the plasma processing apparatus, non-linearity caused by air-specific physical properties such as viscosity, density, etc., and compression delay and transmission delay. Therefore, the controllability is poor, and the controllability is affected by external factors such as temperature, and it is difficult to perform highly accurate position control.

  For this reason, conventionally, the pneumatic actuator has been mainly used for simple work such as constant repetitive work, and has not been used for drive control of an electrode or the like that requires high-precision position control.

  Accordingly, the present invention has been made in view of such problems, and an object of the present invention is to provide a plasma processing apparatus and an upper electrode unit that can perform highly accurate position control using a pneumatic actuator. There is.

  In order to solve the above problems, according to a first aspect of the present invention, there is provided a plasma processing apparatus having plasma processing of an object to be processed by plasma generated using an electrode disposed in a processing container. A sliding support member that slidably supports the electrode in one direction by a slide mechanism, a pneumatic cylinder having a rod connected to the sliding support member, a pneumatic circuit that drives the pneumatic cylinder, There is provided a plasma processing apparatus comprising control means for controlling the position of the electrode by controlling a pneumatic circuit.

  In order to solve the above-mentioned problem, according to a second aspect of the present invention, an upper electrode unit of a plasma processing apparatus for plasma-processing an object to be processed by plasma generated using an upper electrode arranged in a processing container An upper electrode disposed in the processing container, a sliding support member that slidably supports the upper electrode in a vertical direction by a sliding mechanism, and a rod that is connected to the sliding support member. An upper electrode unit is provided, comprising: a pneumatic cylinder having a pneumatic cylinder; a pneumatic circuit that drives the pneumatic cylinder; and a control unit that controls the pneumatic circuit to control the position of the upper electrode.

  According to the first and second aspects of the invention, by providing a sliding support member that supports the electrode slidably in one direction (for example, the vertical direction) separately from the pneumatic cylinder, It eliminates loads (disturbances) in directions other than one direction on the pneumatic cylinder, allowing the pneumatic cylinder to concentrate on movement in one direction. As a result, the position of the electrode can be accurately controlled by the pneumatic cylinder.

  In addition, the upper electrode, the drive mechanism of the upper electrode, and its control means are unitized as in the second aspect, so that the existing plasma processing apparatus can be positioned by a pneumatic cylinder simply by replacing the upper electrode unit. A controllable upper electrode can be easily added.

  The slide mechanism according to the first aspect and the second aspect includes a rail provided along the sliding direction of the electrode on the outer periphery of the sliding support member, and sliding by guiding the rail in the sliding direction. A guide member that is freely supported and fixed to the processing container may be included. As a result, the electrode can be slidably supported with a simple configuration. In this case, the guide member may be fixed to the processing container via a horizontal adjustment member of the electrode. Thereby, the electrode can be easily finely adjusted in the horizontal direction by adjusting the inclination of the guide member by the horizontal direction adjusting member.

  Further, the rod of the pneumatic cylinder according to the first and second aspects may be configured to be disposed substantially at the center of the electrode. As a result, the eccentricity of the load applied to the rod of the pneumatic cylinder and the generation of moment can be suppressed, so that the electrode position can be controlled with higher accuracy.

  The pneumatic circuit in the first and second aspects is provided between the pneumatic source and the pneumatic cylinder, and the flow of compressed air supplied to the pneumatic cylinder based on a control signal from the control means. Is provided in the middle of the switching valve and the pneumatic cylinder, and is supplied to the pneumatic cylinder based on a stop signal from the control means. A drive stop valve that can stop and hold the rod of the pneumatic cylinder by blocking the compressed air may be provided. According to this, the movement position and direction of the electrode can be controlled by the control means. For example, when there is an abnormality in the plasma processing apparatus, the movement of the electrode can be stopped and held.

  Further, a position detecting means for detecting the position of the electrode by detecting the movement of the rod of the pneumatic cylinder in the first and second aspects is provided, and the control means is detected by the position detecting means. The electrode position may be controlled based on a deviation obtained by subtracting the current position of the electrode from the target position of the electrode. In this case, a target position may be set in a plurality of stages until the electrode is moved, and the electrode may be gradually driven. As a result, it is possible to prevent sudden drive and vibration due to air-specific physical properties for driving the pneumatic cylinder, such as viscosity and density, as much as possible. Thereby, even if the upper electrode is driven by the pneumatic cylinder, it is possible to eliminate inconveniences such as rolling up particles in the processing container.

  The electrode in the first aspect is one of a pair of electrodes disposed in parallel to each other in the processing container, and the object to be processed is placed on the other electrode. It may be a thing.

  As described above, according to the present invention, there is provided a plasma processing apparatus and an upper electrode unit capable of highly accurate position control using a pneumatic cylinder by reducing the load applied to the pneumatic cylinder as a pneumatic actuator as much as possible. Can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  As an example of a plasma processing apparatus according to an embodiment of the present invention, a schematic configuration of a parallel plate type plasma processing apparatus 100 is shown in FIGS. FIG. 1 shows a state where the upper electrode is in the retracted position, and FIG. 2 shows a state where the upper electrode is in the processing position. FIG. 3 is an operation explanatory view showing a mechanism for driving the upper electrode shown in FIGS. 1 and 2 in a simplified manner. FIG. 3A shows a state where the upper electrode is in the retracted position, and FIG. 3B shows a state where the upper electrode is in the processing position.

  The plasma processing apparatus 100 according to the present embodiment includes a chamber (processing vessel) 102 made of aluminum whose surface is anodized (anodized), for example, and the chamber 102 is grounded. ing.

  A substantially cylindrical susceptor support 104 for placing an object to be processed, such as a semiconductor wafer (hereinafter simply referred to as “wafer”) W, is provided at the bottom of the chamber 102 via an insulating plate 103 such as ceramic. It has been. A susceptor 105 constituting a lower electrode is provided on the susceptor support 104. A high pass filter (HPF) 106 is connected to the susceptor 105.

  Inside the susceptor support 104, a temperature control medium chamber 107 is provided. Then, the temperature control medium is introduced into the temperature control medium chamber 107 through the introduction pipe 108, circulated, and discharged from the discharge pipe 109. By such circulation of the temperature control medium, the susceptor 105 can be adjusted to a desired temperature.

  The upper center portion of the susceptor 105 is formed into a convex disk shape, and an electrostatic chuck 111 having substantially the same shape as the wafer W is provided thereon. The electrostatic chuck 111 has a configuration in which an electrode 112 is interposed between insulating materials. The electrostatic chuck 111 is applied with a DC voltage of, for example, 1.5 kV from a DC power supply 113 connected to the electrode 112. As a result, the wafer W is electrostatically attracted to the electrostatic chuck 111.

  The insulating plate 103, the susceptor support 104, the susceptor 105, and the electrostatic chuck 111 are supplied with a heat transfer medium (for example, a backside gas such as He gas) on the back surface of the wafer W that is the object to be processed. A gas passage 114 is formed. Heat transfer is performed between the susceptor 105 and the wafer W via the heat transfer medium, and the wafer W is maintained at a predetermined temperature.

  An annular focus ring 115 is disposed on the upper peripheral edge of the susceptor 105 so as to surround the wafer W placed on the electrostatic chuck 111. The focus ring 115 is made of an insulating material such as ceramics or quartz, or a conductive material. By arranging the focus ring 115, the uniformity of etching is improved.

  An exhaust pipe 131 is connected to the bottom of the chamber 102, and an exhaust device 135 is connected to the exhaust pipe 131. The exhaust device 135 includes a vacuum pump such as a turbo molecular pump, and adjusts the inside of the chamber 102 to a predetermined reduced pressure atmosphere (for example, 0.67 Pa or less). A gate valve 132 is provided on the side wall of the chamber 102. By opening the gate valve 132, the wafer W can be loaded into the chamber 102 and the wafer W can be unloaded from the chamber 102. For example, a transfer arm is used for transferring the wafer W.

  An upper electrode 120 is provided above the susceptor 105 so as to face the susceptor 105 in parallel. The upper electrode 120 according to the present embodiment is configured to be driven in one direction, for example, in the vertical direction by the upper electrode driving mechanism 200. Thereby, the interval between the susceptor 105 and the upper electrode 120 can be adjusted. Details of the upper electrode driving mechanism 200 will be described later.

  The upper electrode 120 is supported on the upper inner wall of the chamber 102 via a bellows 122. The bellows 122 is attached to the upper inner wall of the chamber 102 by a fixing means such as a bolt via an annular upper flange 122a, and is attached to the upper surface of the upper electrode 120 by a fixing means such as a bolt via an annular upper flange 122b.

  The upper electrode 120 includes an electrode plate 124 that forms a surface facing the susceptor 105 and has a large number of discharge holes 123, and an electrode support 125 that supports the electrode plate 124. The electrode plate 124 is made of, for example, quartz, and the electrode support 125 is made of, for example, a conductive material such as aluminum whose surface is anodized.

  A gas inlet 126 is provided in the electrode support 125 in the upper electrode 120. A gas supply pipe 127 is connected to the gas inlet 126. Further, a processing gas supply source 130 is connected to the gas supply pipe 127 via a valve 128 and a mass flow controller 129.

For example, an etching gas for plasma etching is supplied from the processing gas supply source 130. FIG. 1 shows only one processing gas supply system including a gas supply pipe 127, a valve 128, a mass flow controller 129, a processing gas supply source 130, and the like, but the plasma processing apparatus 100 includes a plurality of processing gases. A gas supply system is provided. For example, process gases such as CHF ₃ , Ar, and He are independently controlled in flow rate and supplied into the chamber 102.

  A first high-frequency power source 140 is connected to the upper electrode 120, and a first matching unit 141 is inserted in the power supply line. In addition, a low pass filter (LPF) 142 is connected to the upper electrode 120. The first high frequency power supply 140 can output power having a frequency in the range of 50 to 150 MHz. By applying high-frequency power to the upper electrode 120 in this way, a high-density plasma can be formed in a preferable dissociated state in the chamber 102, and plasma processing under low-pressure conditions can be performed compared to the conventional case. Become. The frequency of the output power of the first high frequency power supply 140 is preferably 50 to 80 MHz, and is typically adjusted to the illustrated frequency of 60 MHz or the vicinity thereof.

  A second high-frequency power source 150 is connected to the susceptor 105 serving as a lower electrode, and a second matching unit 151 is inserted in the power supply line. The second high frequency power supply 150 can output electric power having a frequency in the range of several hundred kHz to several tens of MHz. By applying power having a frequency in such a range to the susceptor 105, an appropriate ion action can be given without damaging the wafer W that is the object to be processed. The frequency of the output power of the second high frequency power supply 150 is typically adjusted to 2 MHz or 13.56 MHz as shown.

  Next, details of the upper electrode driving mechanism 200 will be described. The upper electrode driving mechanism 200 includes a substantially cylindrical sliding support member 204 that supports the upper electrode 120 slidably with respect to the chamber 102. The sliding support member 204 is attached to the upper center of the upper electrode 120 with a bolt or the like.

  The sliding support member 204 is disposed so as to be able to enter and exit through a hole 102 a formed in the approximate center of the upper wall of the chamber 102. Specifically, the outer peripheral surface of the sliding support member 204 is slidably supported on the edge of the hole 102 a of the chamber 102 via the slide mechanism 210.

  The slide mechanism 210 is, for example, a guide member 216 fixed to a vertical portion of the fixing member 214 via a fixing member 214 having an L-shaped cross section at the upper portion of the chamber 102, and slidably supported by the guide member 216. A rail portion 212 is formed on the outer peripheral surface of the support member 204 in one direction (vertical direction in the present embodiment).

  The horizontal portion of the fixing member 214 that fixes the guide member 216 of the slide mechanism 210 is fixed to the upper portion of the chamber 102 via an annular horizontal adjustment plate 218. The horizontal adjustment plate 218 is for adjusting the horizontal position of the upper electrode 120. The horizontal adjustment plate 218 is fixed to the chamber 102 by, for example, a plurality of bolts arranged at equal intervals in the circumferential direction, and the amount of inclination of the horizontal adjustment plate 218 with respect to the horizontal direction can be changed by the protruding amount of these bolts. You may make it comprise as follows. Since the horizontal adjustment plate 218 adjusts the inclination with respect to the horizontal direction, the inclination of the guide member 216 of the slide mechanism 210 with respect to the vertical direction is adjusted. Therefore, the horizontal direction of the upper electrode 120 supported via the guide member 216 is adjusted. Can be adjusted. Thereby, the upper electrode 120 can always be kept in a horizontal position by a simple operation.

  A pneumatic cylinder 220 for driving the upper electrode 120 is attached to the upper side of the chamber 102 via a cylindrical body 201. That is, the lower end of the cylinder 201 is airtightly attached with a bolt or the like so as to cover the hole 102 a of the chamber 102, and the upper end of the cylinder 201 is airtightly attached to the lower end of the pneumatic cylinder 220.

  The pneumatic cylinder 220 has a rod 202 that can be driven in one direction, and the lower end of the rod 202 is connected to the upper center of the sliding support member 204 with a bolt or the like. As a result, the rod 202 of the pneumatic cylinder 220 is driven, so that the upper electrode 120 is driven in one direction along the slide mechanism by the slide support member 204. The rod 202 is formed in a cylindrical shape, and the internal space of the rod 202 communicates with a central hole formed in the approximate center of the sliding support member 204 so as to be opened to the atmosphere. As a result, the power supply line from the matching unit 141 and the like can be wired so as to be connected from the internal space of the rod 202 to the upper electrode 120 through the central hole of the sliding support member 204.

  Further, for example, a linear encoder 205 is provided at a side portion of the pneumatic cylinder 220 as position detecting means for detecting the position of the upper electrode 120. On the other hand, an upper end member 207 having an extended portion 207a extending laterally from the rod 202 is provided at the upper end of the rod 202 of the pneumatic cylinder 220. The extended portion 207a of the upper end member 207 is provided with the linear encoder 205. The detection unit 205a is in contact. Since the upper end member 207 is interlocked with the movement of the upper electrode 120, the position of the upper electrode 120 can be detected by the linear encoder 205.

  The pneumatic cylinder 220 is configured by sandwiching a cylindrical cylinder body 222 between an upper support plate 224 and a lower support plate 226. An annular partition member 208 that partitions the pneumatic cylinder 220 into an upper space 232 and a lower space 234 is provided on the outer peripheral surface of the rod 202.

  As shown in FIG. 3, compressed air is introduced into the upper space 232 of the pneumatic cylinder 220 from the upper port 236 of the upper support plate 224. Further, compressed air is introduced into the lower space 234 of the pneumatic cylinder 220 from the lower port 238 of the lower support plate 226. By controlling the amount of air introduced into the upper space 232 and the lower space 234 from the upper port 236 and the lower port 238, the rod 202 can be driven and controlled in one direction (here, the vertical direction). The amount of air introduced into the pneumatic cylinder 220 is controlled by a pneumatic circuit 310 provided in the vicinity of the pneumatic cylinder 220.

  Next, the drive control means 300 of the upper electrode drive mechanism 200 provided in the plasma processing apparatus according to the present embodiment will be described. FIG. 4 is a circuit diagram showing the drive control means 300 of the upper electrode drive mechanism 200. FIG. 5 is a block diagram of the pneumatic circuit 310.

  As shown in FIG. 4, the drive control means 300 includes a pneumatic circuit 310 and a control means 400 that controls the pneumatic circuit 310. The control unit 400 includes a CPU (central processing unit) 420 constituting the main body of the control unit 400, an interface 440 for exchanging various signals with the outside, an interlock circuit 460 for performing a self-diagnosis of the pneumatic circuit 310, and the like. . The interface 440 receives, for example, exchange of control signals with a control device (not shown) that controls the plasma processing apparatus 100 and sensor signals from various sensors. The input signal of the interface 440 includes, for example, an upper electrode drive control signal including target position information for driving the upper electrode 120 to a predetermined target position, a gate valve control signal for controlling the gate valve, and various sensors. There is a sensor signal. As an output signal of the interface 440, an upper electrode position stabilization signal for informing whether or not the position of the upper electrode 120 has been stabilized and whether or not the movement of the upper electrode 120 has been completed, and a transfer arm for transferring the wafer by the upper electrode 120 There is a wafer transfer signal that indicates whether or not the wafer can be transferred into the chamber 102 at a position where it does not hit.

  An example of the sensor signal is a signal from an origin sensor that detects that the upper electrode 120 is at the origin position. The origin here is a position that becomes the origin of the upper electrode position detecting means, for example, the linear encoder 205. Specifically, the origin sensor may be composed of, for example, a contact sensor or an optical sensor. In that case, the origin sensor is provided, for example, inside the upper wall constituting the cylinder 201 on the chamber 102, and the position where the upper end of the sliding support member 204 is detected by the origin sensor, that is, the upper electrode 120 is located on the uppermost side. However, the origin position may be used. Other sensor signals include a transfer confirmation position sensor signal for inquiring whether or not the position of the upper electrode 120 is at a position where the wafer can be transferred. When the transfer confirmation position sensor signal is input, the CPU 420 detects whether or not the upper electrode 120 does not hit the transfer arm that transfers the wafer, that is, whether it is in the retracted position, based on the detection signal from the linear encoder 205. A wafer transfer signal is output via the interface 440.

  When driving the upper electrode 120, the interlock circuit 460 receives a signal from the switch 320 that detects that compressed air is being output from the air pressure source 305 in the air pressure circuit 310, and the compressed air is output from the air pressure source 305. When the operation is performed, that is, when the signal from the switch 320 is ON, a drivable signal is output to the pneumatic circuit 310. When the compressed air is not output from the air pressure source 305, that is, when the signal from the switch 320 is OFF, the drivable signal is stopped in the air pressure circuit 310.

  Further, the interlock circuit 460 stops the drivable signal supplied to the pneumatic circuit 310 when an external interlock signal is input even if the signal from the switch 320 is ON. The interlock signal is input from the control device (not shown) to the control means 400 when an abnormality occurs, for example, in the plasma processing apparatus 100 where it is necessary to stop driving the upper electrode 120.

The CPU 420 controls the pneumatic circuit 310 based on a signal from the interface 440. For example, by performing feedback control based on PID control (control combining proportional operation, differential operation, and integration operation) based on a block diagram as shown in FIG. Controls movement to the target position. In the block shown in FIG. 5, Ref (s) is the target position of the upper electrode 120, and Y (s) is the current position. G (s) is a transfer function. The K _P proportional gain, _{K I} is an integral gain, the _{K D} is the derivative gain, _{K A} is the acceleration feedback gain, _{K V} is the velocity feedback gain.

Specifically, a deviation by subtracting the current position from the target position of the upper electrode 120, an output proportional to the time integral of the deviation to compensate for the steady-state deviation and (adjustable by the integral gain K _I), the change rate an output proportional to the temporal change in the deviation in order to suppress (adjustable by derivative gain K _D), the a PID control by the (adjustable by a proportional gain K _P) output proportional to the deviation performed. In other words, this PID control has a function for predicting a motion proportional to the current deviation (proportional operation), a function for integrating and maintaining past deviation and removing an offset (integration operation), and a function for predicting future motion (differential operation). )It is included.

  Further, in the control of the pneumatic circuit 310 according to the present embodiment, the output of a pressure sensor (not shown) disposed at each port 236, 238 of the pneumatic cylinder 220 is used to deal with disturbance as shown in FIG. Thus, the acceleration feedback control and the output of the linear encoder 205 are taken into the control means 400 as shown in FIG. 4, and the speed feedback control is performed using this output.

  When the position of the upper electrode 120 is controlled, a target position may be set in a plurality of stages until the position where the upper electrode 120 is moved, and the upper electrode 120 may be gradually driven. As a result, it is possible to prevent sudden drive and vibration due to air-specific physical properties for driving the pneumatic cylinder, such as viscosity and density, as much as possible. Thereby, even if the upper electrode is driven by the pneumatic cylinder, it is possible to eliminate inconveniences such as winding up particles in the chamber 102, for example.

  Here, a configuration example of the pneumatic circuit 310 will be described. FIG. 6 is a circuit diagram showing a configuration of the pneumatic circuit 310. 7 and 8 are action explanatory views showing the operation of the pneumatic circuit 310. FIG. 6 shows a neutral state, FIG. 7 shows a state during drive control of the upper electrode 120, and FIG. 8 shows an emergency stop state.

  4 and 6, the pneumatic circuit 310 includes a 5-port solenoid valve 330 that constitutes a switching valve capable of switching a flow path between a neural state and a drive control state by a valve control signal from the CPU 420. A 5-port switching valve 340 is provided in the middle of a pipe line communicating from the 5-port solenoid valve 330 to the upper port 236 of the pneumatic cylinder 220, and a pipe communicating from the 5-port solenoid valve 330 to the lower port 238 of the pneumatic cylinder 220 is provided. A 5-port switching valve 350 is provided in the middle of the road. Each of these five-port switching valves 340 and 350 is a drive stop valve for performing an emergency stop of the pneumatic cylinder 220 and is configured to be controllable by a three-port solenoid valve 360.

  Here, the specific connection relationship of each valve is demonstrated. In the 5-port solenoid valve 330, the air pressure source 305 is connected to the p port, and the a port is connected to the p port of the 5-port switching valve 340. The b port of the 5-port solenoid valve 330 is connected to the p-port of the 5-port switching valve 350. The c port and d port of the 5-port solenoid valve 330 are exhaust ports.

  The 5-port solenoid valve 330 can switch the flow path between an N state, an L state, and an R state. The 5-port solenoid valve 330 is provided with an urging member, for example, a spring on both sides thereof, and is energized so as to be in the N state unless energized by a valve control signal from the control means 400. If, for example, plus energization is performed by the valve control signal, the L state is set against the urging force of the urging member, and if minus energization is set, the R state is set against the urging force of the urging member. When the 5-port solenoid valve 330 is in the N state, each port is cut off. In the L state, the 5-port solenoid valve 330 is connected to the p port and the a port and connected to the d port and the b port. In the R state, the p port and the b port are connected and the c port and the a port are connected. .

  The upper port 236 of the pneumatic cylinder 220 is connected to the a port of the 5-port switching valve 340, and the lower port 238 is connected to the a port of the 5-port switching valve 350. The 5-port switching valves 340 and 350 can switch the flow path to an N state and an L state, respectively. The 5-port switching valves 340 and 350 are each provided with an urging member such as a spring on one side thereof, and are energized so as to be in the N state unless compressed air from the 3-port electromagnetic valve 360 is supplied. When compressed air is supplied from the 3-port solenoid valve 360, the L state is set against the biasing force of the biasing member. In the N state, the 5-port switching valves 340 and 350 are respectively connected to the p port and the b port and connected to the c port and the a port. In the L state, the p port and the a port are connected and the d port and the b port are connected. Connected.

  The air pressure source 305 is connected to the p port of the 3-port solenoid valve 360, and the b port and the a port are connected. The b port of the 3-port solenoid valve 360 is an exhaust port. As shown in FIG. 4, the three-port solenoid valve 360 can switch the flow path between an N state and an L state based on a drive enable signal from the interlock circuit 460. The three-port solenoid valve 360 is provided with an urging member, for example, a spring on one side thereof, and is energized so as to be in the N state if no energization is performed by the drive enable signal from the control means 400. When there is a drive enable signal, the L state is set against the urging force of the urging member. In the 3-port solenoid valve 360, in the N state, the p port is blocked and the b port and the a port are connected. In the L state, the p port and the a port are connected and the b port is blocked.

  In the pneumatic circuit 310 having such a configuration, as shown in FIG. 6, when the switch 320 of the pneumatic source 305 is off, the drive enable signal from the interlock circuit 460 is stopped. The flow path is in the N state, and the flow path of the 5-port solenoid valve 330 is also in the N state. In such a neutral state, the ports 236 and 238 of the pneumatic cylinder 220 are cut off from the pneumatic pressure source 305 by the 5-port solenoid valve 330, so that the upper electrode 120 is held in a stopped state.

  When the switch 320 of the air pressure source 305 is turned on, a drive enable signal is output from the interlock circuit 460, so that the flow path of the 3-port solenoid valve 360 is in the L state. For this reason, the flow paths of the 5-port switching valves 340 and 350 are each in the L state. Accordingly, the compressed air can be sent to the pneumatic cylinder 220 by switching the flow path of the 5-port solenoid valve 330, so that the upper electrode 120 can be driven.

  In this state, when the upper electrode 120 is moved downward, for example, the flow path of the 5-port solenoid valve 330 is set to the L state as shown in FIG. As a result, the compressed air from the pneumatic pressure source 305 is introduced from the upper port 236 of the pneumatic cylinder 220 and discharged from the lower port 238, so that the sliding support member 204 moves downward and the upper electrode 120 moves downward. .

  When the upper electrode 120 is moved upward, for example, from the neutral state shown in FIG. 6, the flow path of the 5-port solenoid valve 330 is set to the N state contrary to the case shown in FIG. Also in this case, since the stop signal from the interlock circuit 460 is turned off, the flow path of the 3-port solenoid valve 360 is in the L state. For this reason, the flow paths of the 5-port switching valves 340 and 350 are each in the L state. Thereby, the compressed air from the pneumatic pressure source 305 is introduced from the lower port 238 of the pneumatic cylinder 220 and discharged from the upper port 236, so that the sliding support member 204 moves upward and the upper electrode 120 moves upward. .

  FIG. 8 shows a circuit state of the pneumatic circuit 310 when the emergency stop is performed while driving the upper electrode. Since the stop signal from the interlock circuit 460 is turned on, the flow path of the 3-port solenoid valve 360 is in the N state. For this reason, the flow paths of the 5-port switching valves 340 and 350 are each in the N state. As a result, compressed air from the pneumatic source 305 is introduced from the lower port 238 of the pneumatic cylinder 220, and compressed air from the pneumatic source 305 is blocked from the upper port 236 and the lower port 238 of the pneumatic cylinder 220. The moving support member 204 stops and the upper electrode 120 stops.

  FIG. 9 and FIG. 9 show experimental results when the specific control shown in FIG. 5 is performed by setting the target position in a plurality of stages up to the position where the upper electrode 120 is moved by the pneumatic circuit 310 according to the present embodiment. 10 shows. FIG. 9 is a graph of the position and time of the upper electrode 120 when the upper electrode 120 is gradually driven upward, and FIG. 10 is a position of the upper electrode 120 when the upper electrode 120 is gradually driven downward. It is a graph of time. 9 and 10, it is understood that when the upper electrode 120 is driven upward and downward, the follow-up control is stably performed with good controllability to the target position.

  When various indicators were measured based on such experimental results, it can be seen that the upper electrode stopping system is about ± 0.15 mm and the operation speed is about 60 mm / sec, which is sufficiently practical. As described above, the plasma processing apparatus 100 according to the present embodiment enables highly accurate position control.

  In the plasma processing apparatus according to this embodiment as described in detail above, by providing the sliding support member 204 that supports the upper electrode 120 slidably in one direction (for example, the vertical direction) separately from the pneumatic cylinder 220. , Loads (disturbances) in directions other than one direction applied to the pneumatic cylinder 220 can be eliminated, and the pneumatic cylinder 220 can be concentrated on the movement in one direction. Thus, the position control of the upper electrode 120 can be performed with high accuracy by the pneumatic cylinder 220.

  Further, since the rod 202 of the pneumatic cylinder 220 is configured to be disposed substantially at the center of the upper electrode 120, it is possible to suppress the eccentricity of the load applied to the rod 202 of the pneumatic cylinder 220 and the generation of moment, and thus more accuracy. The electrode position can be controlled well.

  In this embodiment, the upper electrode 120 is driven by the pneumatic cylinder 220, but the lower electrode may be slidably supported and driven by the pneumatic cylinder 220. In this regard, the lower electrode on which the object to be processed such as a wafer or a liquid crystal substrate is mounted is provided with various additional mechanisms such as a mechanism for holding the object to be processed, a backside gas mechanism for the object to be processed, and an electrode temperature adjustment mechanism. On the other hand, the upper electrode has few such additional mechanisms. Therefore, rather than driving the lower electrode, the load on the rod 202 of the pneumatic cylinder 220 can be reduced by driving the upper electrode 120 by the pneumatic cylinder as in this embodiment, and more accurately. Electrode position control can be performed.

  Further, the parts shown in FIG. 3, that is, the upper electrode 120, the driving mechanism 200 of the upper electrode 120, the pneumatic circuit 310, and the control means 400 are unitized to form an upper electrode unit. However, it is possible to easily add the upper electrode 120 whose position can be controlled by a pneumatic cylinder only by exchanging the upper electrode unit.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above embodiment, the plasma etching apparatus has been described as an example of the plasma processing apparatus, but the present invention can also be applied to other processing apparatuses such as a film forming apparatus and an ashing apparatus. In the above embodiment, the semiconductor wafer is described as an example of the object to be processed. However, the object is not necessarily limited to this, and the object to be processed is for a flat display (FPD) such as a liquid crystal display (LCD). It may be a glass substrate, that is, an FPD substrate such as an LCD substrate.

  The present invention is applicable to a plasma processing apparatus and an upper electrode unit.

It is sectional drawing which shows schematic structure of the plasma processing apparatus concerning embodiment of this invention. It is sectional drawing which shows the case where the upper electrode of the plasma processing apparatus in the embodiment exists in the position at the time of a process. It is the figure which simplified and showed the upper electrode unit concerning this embodiment, Comprising: The figure (a) is a case where an upper electrode exists in a retracted position, The figure (b) shows the upper electrode in a processing position. This is the case. It is a figure which shows the structure of the drive control means of the upper electrode drive mechanism concerning this embodiment. FIG. 5 is a block diagram in the position control of the upper electrode performed by the CPU shown in FIG. 4. It is a figure which shows the structure of the pneumatic circuit concerning this embodiment. It is operation | movement explanatory drawing of the pneumatic circuit concerning this embodiment. It is operation | movement explanatory drawing of the pneumatic circuit concerning this embodiment. It is a figure which shows the result at the time of carrying out the upper drive concerning this embodiment, and carrying out position control. It is a figure which shows the result at the time of carrying out the downward drive of the upper electrode concerning this embodiment, and performing position control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Plasma processing apparatus 102 Chamber 104 Susceptor support stand 105 Susceptor 115 Focus ring 120 Upper electrode 122 Bellows 123 Discharge hole 124 Electrode plate 125 Electrode support body 126 Gas inlet 127 Gas supply pipe 130 Process gas supply source 131 Exhaust pipe 132 Gate valve 135 Exhaust device 140 High frequency power supply 141 Matching device 150 High frequency power supply 151 Matching device 200 Upper electrode drive mechanism 201 Cylindrical body 202 Rod 202 Chamber 204 Slide support member 205 Linear encoder 208 Partition member 210 Slide mechanism 212 Rail portion 214 Fixing member 216 Guide member 218 Level adjustment plate 220 Pneumatic cylinder 222 Cylinder body 224 Upper support plate 226 Lower support plate 232 Upper space 234 Lower space 236 Upper port 38 lower port 300 drive controller 310 pneumatic circuits 305 air pressure source 320 Switch 330 5 port solenoid valve 340 5-port switching valve 350 5-port switching valve 360 three-port solenoid valve 400 control unit 420 CPU
440 interface 460 interlock circuit

Claims (15)

A plasma processing apparatus for plasma processing an object to be processed by plasma generated using an electrode disposed in a processing container,
A sliding support member for slidably supporting the electrode in one direction by a sliding mechanism;
A pneumatic cylinder having a rod connected to the sliding support member;
A pneumatic circuit for driving the pneumatic cylinder;
Control means for controlling the position of the electrode by controlling the pneumatic circuit;
A plasma processing apparatus comprising: The slide mechanism is
A rail provided along the sliding direction of the electrode on the outer periphery of the sliding support member;
A guide member that guides the rail in the sliding direction and supports the rail slidably, and is fixed to the processing container.
The plasma processing apparatus according to claim 1. The plasma processing apparatus according to claim 1, wherein the guide member is fixed to the processing container via a horizontal adjustment member of the electrode. The plasma processing apparatus according to claim 1, wherein the rod of the pneumatic cylinder is disposed substantially at the center of the electrode. The pneumatic circuit is provided in the middle of the pneumatic source and the pneumatic cylinder, and switches the flow of compressed air supplied to the pneumatic cylinder based on a control signal from the control means, thereby moving the rod of the pneumatic cylinder. A switching valve that can be driven;
The rod of the pneumatic cylinder can be stopped and held by blocking compressed air supplied to the pneumatic cylinder based on a stop signal from the control means, provided in the middle of the switching valve and the pneumatic cylinder. A drive stop valve;
The plasma processing apparatus according to claim 1, further comprising: A position detecting means for detecting the position of the electrode by detecting the movement of the rod of the pneumatic cylinder;
2. The plasma according to claim 1, wherein the control unit performs position control of the electrode based on a deviation obtained by subtracting a current position of the electrode detected by the position detection unit from a target position of the electrode. Processing equipment. The plasma processing apparatus according to claim 6, wherein the control unit sets a target position in a plurality of steps to a position where the electrode is moved, and gradually drives the electrode. The electrode is one of a pair of electrodes disposed in parallel with each other in the processing container,
The plasma processing apparatus according to claim 1, wherein the object to be processed is placed on the other electrode. An upper electrode unit of a plasma processing apparatus for plasma-treating an object to be processed by plasma generated using an upper electrode disposed in a processing container,
An upper electrode disposed in the processing vessel;
A sliding support member that slidably supports the upper electrode in a vertical direction by a sliding mechanism;
A pneumatic cylinder having a rod connected to the sliding support member;
A pneumatic circuit for driving the pneumatic cylinder;
Control means for controlling the position of the upper electrode by controlling the pneumatic circuit;
An upper electrode unit comprising: The slide mechanism is
A rail provided on the outer periphery of the sliding support member along the sliding direction of the upper electrode;
A guide member that guides the rail in the sliding direction and supports the rail slidably, and is fixed to the processing container.
The upper electrode unit according to claim 9. The upper electrode unit according to claim 9 or 10, wherein the guide member is fixed to the processing container via a horizontal direction adjustment member of the upper electrode. The upper electrode unit according to claim 9, wherein the rod of the pneumatic cylinder is disposed substantially at the center of the upper electrode. The pneumatic circuit is provided in the middle of the pneumatic source and the pneumatic cylinder, and switches the flow of compressed air supplied to the pneumatic cylinder based on a control signal from the control means, thereby moving the rod of the pneumatic cylinder. A switching valve that can be driven;
The rod of the pneumatic cylinder can be stopped and held by blocking compressed air supplied to the pneumatic cylinder based on a stop signal from the control means, provided in the middle of the switching valve and the pneumatic cylinder. A drive stop valve;
The upper electrode unit according to claim 9, wherein the upper electrode unit is provided. A position detecting means for detecting the position of the upper electrode by detecting the movement of the rod of the pneumatic cylinder;
10. The position of the upper electrode is controlled based on a deviation obtained by subtracting a current position of the upper electrode detected by the position detecting unit from a target position of the upper electrode. The upper electrode unit described. 15. The upper electrode unit according to claim 14, wherein the control means sets a target position in a plurality of stages to a position where the upper electrode is moved, and gradually drives the upper electrode.

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