JP2011138671A - Striker-type plasma generation device and plasma processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a striker type plasma generation apparatus for generating higher-quality plasma while utilizing a target material to a maximum by stabilizing the contacting operation of a striker over a long period, and to provide a plasma processing apparatus using the same. <P>SOLUTION: When plasma processing starts, a striker arm begins rotating (steps S2 and S3), and even after a striker tip 35 contacts a cathode 2, a servo motor 40 continues to drive the striker arm to rotate. When a reversal condition is met, namely when the load on the striker arm exceeds a prescribed value, the motor 40 is instructed to operate in reverse, and the striker tip 35 is moved away from the cathode 2 (steps S4 and S5). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a plasma generating apparatus in which a plasma source is provided as a cathode, an anode is provided in front of or around the cathode, and arc discharge is performed between the cathode and the anode to generate plasma from the cathode surface, and The present invention relates to a plasma processing apparatus that performs plasma processing such as film formation using plasma generated by a plasma generator. More specifically, the present invention relates to a striker type plasma generator having an arc discharge striker mechanism and a plasma processing apparatus using the same.

  In general, it is known that the surface characteristics of a solid can be improved by forming a thin film on the surface of the solid material or implanting ions in a plasma. A film formed using a plasma containing metal ions or non-metal ions enhances the wear resistance and corrosion resistance of the solid surface, and is useful as a protective film, an optical thin film, a transparent conductive film, and the like. In particular, a carbon film using carbon plasma has a high utility value as a diamond-like carbon film (referred to as a DLC film) made of an amorphous mixed crystal having a diamond structure and a graphite structure.

  As a method for generating plasma containing metal ions and non-metal ions, there is a vacuum arc plasma method. The vacuum arc plasma is a plasma formed by an arc discharge generated between the cathode and the anode, and the cathode material evaporates from the cathode spot existing on the cathode surface. Moreover, when reactive gas is introduce | transduced as atmospheric gas, reactive gas is also ionized simultaneously. An inert gas (referred to as a rare gas) may be introduced together with the reactive gas, or the inert gas may be introduced instead of the reactive gas. Using such plasma, surface treatment can be performed by forming a thin film on a solid surface or implanting ions.

  In general, in vacuum arc discharge, vacuum arc plasma constituent particles such as cathode material ions, electrons, and cathode material neutral atomic groups (atoms and molecules) are emitted from the cathode spot, and at the same time, from sub-micron to several hundred microns (0. 0). Cathode material fine particles called droplets having a size of 01 to 1000 μm are also emitted. When the droplets adhere to the surface of the object to be processed, the uniformity of the thin film formed on the surface of the object to be processed is lost, causing defects in the thin film, which affects the result of surface treatment such as film formation.

Japanese Patent Laid-Open No. 2002-8893 (Patent Document 1) and Japanese Patent Laid-Open No. 2002-25794 (Patent Document 2) disclose conventional plasma processing apparatuses.
Conventionally, in a plasma generation unit of a plasma processing apparatus, an electric spark is generated between a cathode and a trigger electrode, and a plasma is generated by generating a vacuum arc between the cathode and the anode. A rotating electric spark generating mechanism called a striker is used for the trigger electrode.

  FIG. 11 shows an example of a conventional rotating electric spark generating mechanism disclosed in Patent Document 2. The plasma generator 200 is provided with a cathode 202 connected to an arc power supply 201, and a plasma source supply source (hereinafter referred to as a target) 203 is installed on the cathode 202. The striker 204 is rotatably arranged around the rotation shaft 205 so as to come into contact with and away from the target 203. That is, after the striker arm of the striker 204 is rotated by a predetermined angle and brought into contact with the target 203, the striker arm is driven reversely and separated.

  An arc current is passed from the arc power source 201 and an arc voltage of about −30 V is applied to the striker 204 to contact the target 203, thereby causing arc discharge between the cathode 202 and the striker 204 via the cathode 202. Thus, plasma 206 is generated. The plasma 206 is guided from the plasma generator 200 to the plasma processing chamber 209 through the curved magnetic field duct 207 and the straight magnetic field duct 208. Magnetic field generating DC power supplies 210 and 211 are connected to the curved magnetic field duct 207 and the straight magnetic field duct 208, respectively. A voltage applied by the DC power source 214 or the high frequency power source 215 is applied to the stage 212 in the plasma processing chamber 209. The workpiece 213 placed on the stage 212 is subjected to surface treatment by irradiation with plasma 206 introduced through a magnetic duct. In the plasma processing chamber 209, the reaction gas and the plasma flow are exhausted to the outside by the exhaust pump 216.

JP 2002-8893 A JP 2002-25794 A

  In the rotating electric spark generating mechanism, the target material gradually wears and the contact position changes as the arc discharge is repeated due to the contact of the tip of the striker. However, since the conventional striker rotation drive is performed by setting the rotation limit angle of the striker arm to a predetermined angle in advance, the tip of the striker does not contact the target accurately when the wear progresses, and the arc There have been problems such as insufficient discharge or failure.

  In view of the above problems, the object of the present invention is to make the contact action by the striker stable over a long period of time, to make the target material available to the maximum, and to realize high quality of the generated plasma. A striker type plasma generator and a plasma processing apparatus using the same are provided.

  According to a first aspect of the present invention, a plasma constituent material supply source is a cathode, an anode is provided in front of or around the cathode, and the tip of an arm pivotally supported by a rotary drive source is provided as the supply source. A striker that causes arc discharge by contacting the striker, and a rotation control device that controls rotation of the rotation drive source in a direction in which the striker is brought into contact with or separated from the supply source, and the cathode is generated by the occurrence of the arc discharge. In the plasma generating apparatus for generating arc plasma between the anode and the anode, the rotation control device has a predetermined amount of load applied to the striker when the tip is brought into contact with the supply source by rotation of the arm. Rotation control means for continuing the rotation in the contact direction until the reversal condition exceeding is satisfied, and for reversing and rotating the arm in the separation direction when the reversal condition is satisfied It is a Ranaru plasma generating device.

  According to a second aspect of the present invention, in the first aspect, when an overload occurs in the output shaft of the rotary drive source, a torque limiter that interrupts transmission of torque to the arm is provided in the output shaft, A timing means for measuring a rotation continuation time from the start of the rotation, and the rotation control means is based on the fact that the time measured by the time measuring means reaches a predetermined time after the interruption by the torque limiter has occurred. It is a plasma generator having a time passage judging means for judging that the inversion condition is satisfied.

  According to a third aspect of the present invention, in the first aspect, when an overload occurs in the output shaft of the rotary drive source, a torque limiter that interrupts transmission of torque to the arm is provided in the output shaft, An angle measuring means for measuring a rotation angle from the start of rotation, wherein the rotation control means is based on the fact that the angle measured by the angle measuring means has reached a predetermined angle after being interrupted by the torque limiter; It is a plasma generator having a rotation angle determination means for determining that the inversion condition is satisfied.

  According to a fourth aspect of the present invention, in the first aspect, the rotation control unit includes a torque change amount measuring unit that sequentially extracts and measures a torque change amount per unit time from the start of the rotation of the arm. Is a plasma generator having a torque change amount judging means for judging that the reversal condition is satisfied when a torque change amount exceeding a predetermined value is continuously measured a predetermined number of times or more.

  According to a fifth aspect of the present invention, in the fourth aspect, the rotation control unit is configured to measure a torque change amount exceeding a predetermined specified value and to exceed the torque change amount before the inversion condition is satisfied. When the number of times reaches the specified number of times, a specified value update processing means for updating the specified value added with an excess of the torque change amount as a new specified value and determining whether or not the inversion condition is satisfied based on the specified value. It has a plasma generator.

  According to a sixth aspect of the present invention, in the fifth aspect, the rotation control means includes an upper limit reaching determination means for determining whether or not the updated specified value has reached an upper limit value, and the updated specified value. Is a plasma generator including alarm generating means for generating an alarm when it is determined that the upper limit has been reached.

  According to a seventh aspect of the present invention, in any one of the fourth, fifth, and sixth aspects, the torque change amount measuring unit measures a current value of the rotation drive source motor to obtain a torque change amount. It is a plasma generator comprising motor current measuring means.

  An eighth aspect of the present invention is the plasma generator according to any one of the first to seventh aspects, wherein the material of the arm is formed from a heat-resistant metal material having higher heat resistance than a stainless steel material.

  A ninth aspect of the present invention is the plasma generator according to any one of the first to seventh aspects, wherein the material of the arm is formed from a metal material having a Young's modulus higher than that of a stainless steel material.

  A tenth aspect of the present invention is the plasma generator according to the eighth or ninth aspect, wherein the material of the arm is made of any one of molybdenum, tungsten, titanium, inconel, or a heat resistant alloy composed of two or more of these. is there.

  In an eleventh aspect of the present invention, in any one of the first to tenth aspects, a shaft end of the output shaft is attached to a fitting hole formed in one end of the arm, and the arm and the output shaft are connected. The plasma generator is connected and the fitting hole and the shaft end have a non-circular cross-sectional shape.

  According to a twelfth aspect of the present invention, in any one of the first to tenth aspects, a retaining engagement portion that engages with each other is formed at an intermediate portion of each of the fitting hole and the shaft end portion in the axial direction. It is a plasma generator.

  A thirteenth aspect of the present invention is supplied from the plasma generator according to any one of the first to twelfth aspects, a plasma transport pipe for transporting plasma generated by the plasma generator, and the plasma transport pipe A plasma processing apparatus includes a plasma processing unit that processes an object to be processed with plasma.

  According to the first aspect of the present invention, in the striker-type plasma generator, the amount of load applied to the striker when the tip is brought into contact with the supply source by the rotation of the arm by the rotation control means. Rotation in the contact direction is continued until a reversal condition exceeding a predetermined amount is satisfied, and when the reversal condition is satisfied, the arm is reversed and rotated in the separation direction, so that the supply source (target) When the reversal condition is satisfied after contact, the striker can be separated to eliminate the risk of overloading. Therefore, in this embodiment, the contact action by the striker can be accurately performed over a long period of time, and the target material can be effectively utilized to the maximum extent. The load applied to the striker can be detected by directly or indirectly measuring the drive current, torque change amount, striker arm angle, arm rotation time, and the like of the rotary drive source motor.

  In the conventional method of fixing the setting range of the rotation angle, if it is fixed narrowly, troubles such as non-occurrence of arc discharge and insufficient discharge are caused. In the present invention, since the inversion condition for separating after the contact state of the striker is provided, the striker can be separated at an appropriate timing without occurrence of arc discharge or insufficient discharge.

  The predetermined amount according to the present invention is preferably determined by actually measuring a change in which the target material is consumed with repeated striker rotation. At this time, obtaining actual measurement data for each type of target material is also effective from the viewpoint of improving the accuracy of separation timing. Further, an electric motor such as a servo motor or a pulse motor can be used as the rotational drive source.

  For example, in the initial stage of starting to use a new target, since the contact continues until the striker comes off, the load on the rotary motor of the striker arm increases, causing motor breakage or damage to the striker, Furthermore, there is a risk of damage to the target itself. Therefore, according to the second embodiment, a torque limiter suitable as a load limiting unit capable of instantaneously interrupting the torque overload of the rotary motor is provided on the output shaft, and the time lapse determining unit interrupts the torque limiter. After that, since it is determined that the reversal condition is satisfied based on the time measured by the time measuring means reaching a predetermined time, for example, by monitoring the elapsed time from the start of the rotation of the striker, It is possible to accurately grasp the reversal condition and accurately perform the contact action by the striker over a long period of time.

  According to the third aspect of the present invention, the reversal condition is satisfied based on the fact that the angle measured by the angle measuring means reaches a predetermined angle after the turning by the torque limiter is caused by the turning angle determining means. Therefore, for example, by measuring the rotation angle from the start of rotation of the striker with an angle detection sensor, the reversing condition can be accurately grasped and the contact action by the striker can be accurately determined over a long period of time. Can be done. As the angle detection sensor, an optical sensor, a magnetic sensor, a contact sensor, or the like that detects the displacement of the striker arm can be used.

  According to the fourth aspect of the present invention, the torque change amount measuring means sequentially extracts and measures the torque change amount (differential change amount) per unit time from the start of rotation of the arm, and the torque change Since the amount determining means determines that the reversal condition is satisfied when the amount of torque change exceeding a predetermined specified value is continuously measured a predetermined number of times or more, it is determined that the reversal condition is satisfied. Even if the amount of torque change is detected at, it can be excluded as noise unless the amount of torque change exceeding the specified value is measured continuously for a predetermined number of times or more, and torque is set as an inversion condition. Malfunction can be prevented.

  When torque is set as a reversal condition, it is difficult to sufficiently predict and determine a change with time due to long-term operation even if the predetermined value is determined in advance based on experience values or the like. Therefore, according to the fifth aspect of the present invention, the specified value update processing means measures a torque change amount exceeding a predetermined specified value until the inversion condition is satisfied, and exceeds the torque change amount. When the number of times reaches a prescribed number, for example, 70% of the total, the prescribed value obtained by adding an excess of the torque change amount is updated as a new prescribed value, and whether or not the inversion condition is satisfied is determined based on the prescribed value. Therefore, when a situation occurs in which the amount of torque change exceeding the initially specified value occurs, the specified value with the excess amount of torque change added is updated as a new specified value to follow the change over time. Therefore, the inversion condition can be determined with high accuracy over a longer period of time. A predetermined additional value may be used as the excess to be added, or may be determined by selecting the maximum value among a plurality of detected values.

  According to the sixth aspect of the present invention, the upper limit reaching determination means determines whether or not the updated specified value has reached an upper limit value, and the updated specified value has reached the upper limit value. Since the alarm is generated by the alarm generation means when it is determined that the device reaches the upper limit value without updating the specified value more than necessary, it is possible to notify an alarm of the possibility of device abnormality or trouble occurrence by reaching the upper limit value. This contributes to improving the safety of striker-type plasma generators and maintaining and promoting long-term stable operation.

  According to the seventh aspect of the present invention, since the motor current measuring means measures the current value of the rotational drive source motor to obtain the torque change amount, the differential change amount of the torque per minute time is stabilized. In addition, the reversal condition can be accurately grasped by performing precisely, and the contact action by the striker can be accurately performed over a long period of time.

  In the striker-type plasma generator, when the striker rotating operation is repeated, the temperature of the striker arm becomes high due to heat generated by arc discharge. Since stainless steel (SUS) is used for the conventional striker, precipitates are generated on the surface due to high temperature, which adversely affects the device characteristics of the plasma generator. Therefore, when the contact action by the striker is prolonged by implementing the present invention, the striker material has a considerable influence on the quality of the generated plasma. Therefore, according to the eighth embodiment of the present invention, since the material of the arm is formed of a heat-resistant metal material having higher heat resistance than stainless steel material, the precipitates due to the high temperature accompanying the repetition of the striker rotation operation Generation can be suppressed and high-quality plasma generation can be performed.

  Conventionally, for example, SUS304 was used for the striker. However, for example, since the Young's modulus of SUS304 is 193 to 197 GPa, the arm amplitude generated during the hammering operation in which the striker arm is rotated by about 90 ° to perform contact operation becomes large. There was a trend. Therefore, the controllability of the initial discharge by the striker is reduced. Therefore, according to the ninth aspect of the present invention, since the material of the arm is formed of a metal material having a higher Young's modulus than the stainless steel material, the arm amplitude generated when the contact operation is performed is reduced, and the initial by the striker is reduced. Controllability of discharge can be improved.

  According to the tenth aspect of the present invention, the arm formed of a refractory metal material of any one of molybdenum, tungsten, titanium, inconel or a heat-resistant alloy composed of two or more of these, provides heat resistance and arm amplitude. Instead of SUS which has a problem in restraint, a striker arm excellent in heat resistance and arm amplitude restraining function can be configured, and durability against repeated use of the striker can be provided.

  Conventionally, the striker arm has had the round member of the output shaft inserted into the shaft hole of the arm. However, the striker arm has a drawback in that it is difficult to align the rotational direction when fixing because of the round member. Therefore, according to an eleventh aspect of the present invention, a shaft end portion of the output shaft is attached to a fitting hole formed at one end of the arm to connect the arm and the output shaft, and the fitting hole In addition, since the cross-sectional shape of the shaft end is made non-circular, the position in the rotational direction is uniquely and accurately determined, which contributes to improved rotation accuracy and improved maintainability.

  According to the twelfth aspect of the present invention, since the retaining engagement portion that engages with each other is formed at each of the axially intermediate portions of the fitting hole and the shaft end portion, the striker rotation operation is repeated. Accordingly, the output shaft is not displaced in the axial direction, and the initial discharge can be stably performed, which contributes to the quality improvement of the generated plasma.

  According to the thirteenth aspect of the present invention, the plasma generated by performing the initial discharge stably by the plasma generator according to any one of the first to twelfth aspects is transferred to the plasma via the plasma transport tube. Since the film can be supplied to the plasma processing unit to perform the film forming process or the like using the plasma, stable operation can be performed without causing an arc discharge defect, and the processing efficiency of the film forming can be improved.

It is a cross-sectional schematic block diagram of the plasma processing apparatus with which the striker type plasma generator which concerns on embodiment of this invention was installed. It is the cross-sectional schematic of the plasma generation part 4 periphery of the said plasma generator. It is a schematic block diagram of the striker rotation type electric spark generation mechanism used for the said plasma generator. It is a structural diagram of the striker 5 of the striker rotation type electric spark generating mechanism. It is a motor drive mechanism block diagram of the striker 5. FIG. It is a control block diagram of the said plasma processing apparatus. It is a basic flowchart of striker rotation drive control concerning the present invention. It is a striker drive control flowchart of the torque change amount (differential change amount) management system in the present embodiment in the plasma processing apparatus. It is the striker rotation drive control flowchart of the timer monitoring system in the said plasma processing apparatus. It is a striker rotation drive control flowchart of the rotation angle management system in the said plasma processing apparatus. It is a cross-sectional schematic block diagram of the conventional striker type plasma generator.

  Hereinafter, a striker type plasma generating apparatus and a plasma processing apparatus according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view of a plasma processing apparatus in which a striker rotation type plasma generator 1 according to the present invention is installed. In the plasma generation unit 4, a supply source of a plasma constituent material is a cathode (target) 2, and a cylindrical anode 3 is disposed in front of the cathode 2. The trigger electrode striker 5 is rotatably provided so as to be able to approach and retract with respect to the cathode 2. The arm material of the striker 5 uses molybdenum. The anode 3 is composed of an electrode cylinder whose inner wall is multi-divided. An electric spark is generated between the cathode 2 and the striker 5 in a vacuum atmosphere, and a vacuum arc is generated between the cathode 2 and the anode 3 to generate plasma P. The cathode 2 is a supply source of a plasma constituent material, and the forming material is not particularly limited as long as it is a conductive solid, and a single metal, an alloy, an inorganic simple substance, an inorganic compound (metal oxide / nitride), etc. Or 2 or more types can be mixed and used. The vacuum arc discharge in the plasma generation unit 4 discharges the vacuum arc plasma constituent particles such as target material ions, electrons, and neutral particles (atoms and molecules) of the cathode material, and at the same time, from submicron to several hundred microns (0.01 to Cathode material fine particles (hereinafter referred to as “droplet D”) having a size of 1000 μm are also emitted. The generated plasma P travels in the plasma traveling path 6 and travels to the second traveling path by the magnetic field formed by the bending magnetic field generators 8 and 8 in the bending portion 7. At this time, since the droplet D is electrically neutral and not affected by the magnetic field, the droplet D travels straight through the Dopplet traveling path 9 and is collected by the droplet collecting unit 10. The bent portion 7 is provided with a straight line connected to the second traveling path, and baffles 11, 12 on which droplets D collide and adhere to the inner walls of the traveling paths of the plasma P such as the Dopplet traveling path 9. 17 is provided. A magnetic field generator 18 for generating a plasma traveling magnetic field is installed in the straight line.

  The second traveling path is composed of a diameter expansion tube 13 having a plurality of baffles 12 provided on the inner wall, and the diameter expansion tube 13 is provided with a magnetic field generator 20 for generating a plasma traveling magnetic field. When the plasma P travels in the diameter expansion tube 13, the remaining droplet D collides with and adheres to the baffle 12, and the droplet D is further removed. The diameter expansion pipe 13 is inclined with respect to the straight line. The end of the expanded diameter tube 13 is connected to the plasma processing unit 15 via the reduced diameter tube 23. The plasma P from which the droplets D have been removed is supplied to the plasma processing unit 15 by the magnetic fields of the magnetic field generators 14 and 14, and the workpiece 16 can be plasma processed. A baffle 19 is also installed in the reduced diameter tube 23. Reactive gas is introduced into the plasma processing unit 15 as necessary by a gas introduction system (not shown), and the reaction gas and plasma flow are exhausted by a gas exhaust system (not shown). In the present embodiment, a plurality of bent traveling paths are provided between the plasma generating unit 4 and the plasma processing unit 15. However, the present invention is not limited to this, and various types of traveling paths having substantially L-shaped traveling paths are provided. It can be applied to a plasma processing apparatus.

  FIG. 2 is a schematic cross-sectional view of the periphery of the plasma generator 4. As shown in FIG. 2A, the striker 5 is composed of a striker arm that is pivotally supported around a rotation shaft 24. A voltage is applied between the anode inner wall 28 and the striker 5 and the target of the cathode 2 via the currents 26 and 27 by the power source 25. The plasma generating portion outer wall 29 is not in contact with the anode inner wall 28, and electrical neutrality is maintained by insulating members 30 and 31 attached to the upper and lower ends of the outer wall 29. A pipe end 33 of the plasma traveling path 6 is connected to the plasma outlet side of the plasma generating part outer wall 29. The electrode cylinder of the anode 3 is opened on the cathode 2 side to form a gap 34.

  A vacuum arc discharge is induced between the discharge surface 32 of the cathode 2 and the anode inner wall 28 by separating the striker at the contact position indicated by the solid line in the separation direction indicated by the broken line. When the striker 5 is swung by receiving a rotational drive from a rotational drive source (not shown), and the striker 5 at a separated position is brought into contact with the discharge surface 32, the rotational drive source (a motor 40 in FIG. 5 described later) is used. The torque reaction force of the striker that has contacted is detected, and it is determined that the striker is in contact. Further, a filter coil 22 is disposed on the plasma outlet side of the plasma generating unit 4 to form a plasma traveling magnetic field B2. The stabilizing magnetic field B1 generated by the target coil 21 is formed in a phase (caps) opposite to the plasma traveling magnetic field B2, so that stable plasma can be generated. As shown in (2B) of FIG. 2, when the stabilizing magnetic field B1 generated by the target coil 21 is in-phase (mirror), the stability of the arc spot is reduced, but the plasma generation efficiency is improved. Yes.

FIG. 3 shows a schematic configuration of a striker rotation type electric spark generating mechanism used in the plasma generator 1. FIG. 4 shows the structure of the striker 5 of the striker rotation type electric spark generating mechanism. 4 (4A) shows the side of the striker 5, and FIG. 4 (4B) shows the front of the striker 5. FIG. FIG. 5 shows the motor drive mechanism of the striker 5.
The striker 5 is rotatably supported in a range of about 90 ° (maximum 95 °), and includes a striker arm having a length that swings from a stand-by standby state and strikes the cathode target surface. In the stand-by standby state, the striker 5 is held at a position where it is retracted to the outside of the anode wall from the doorway (not shown) of the anode 3. The drive side end of the striker arm is connected to the output shaft 36 of the motor 40. A striker tip 35 is attached to the working end of the striker arm. The striker chip 35 is made of the same or different kind of conductive material as the cathode 2. In this embodiment, a carbon tip is used for the striker tip 35 with respect to the carbon cathode. The anode 3 is also made of carbon, and an arc power source 37 is connected between the cathode 2 and the anode 3. The entire plasma generation unit 4 is maintained in an electrically neutral state. An arc power source 37 is also applied to the striker 5. 150V is applied at the time of the initial discharge hitting the cathode target surface, and the applied voltage is switched to 25V after the initial discharge.

  As shown in FIG. 4 (4A), the output shaft 36 of the motor 40 has a non-circular cross-sectional shape that combines a semicircle and a triangular shape. In accordance with this, a fitting hole having a similar shape is also formed in the drive side end portion of the striker arm. Accordingly, since the shaft end portion of the non-circular output shaft 36 having the same shape is axially attached to the non-circular fitting hole formed in the drive side end portion, and the striker arm and the output shaft 36 are connected, the position in the rotational direction is Is uniquely and accurately determined, which contributes to improved rotation accuracy and maintainability. Not only the non-circular shape but also a cross-sectional shape such as a polygonal shape or an asymmetric quadrilateral shape has the same effect.

As shown in FIG. 4 (4B), a hole 39 is formed in the middle of the tip of the output shaft 36 of the motor 40 so as to fit into the projection 38 in the middle of the fitting hole. Accordingly, the structure in which the hole 39 is fitted to the protrusion 38 forms a retaining engagement portion that engages with the striker arm and the output shaft 36 in the axial direction, so that the striker rotation operation is repeated. The output shaft 36 is not displaced in the axial direction, the initial discharge can be stably performed, and the quality improvement of the generated plasma can be contributed.
As shown in FIG. 5, a torque limiter 41 is attached to the output shaft 36 of the motor 40. The torque limiter 41 is fixed to the fixed portion 42.

FIG. 6 shows a control block diagram of the plasma processing apparatus of this embodiment.
The control unit of the plasma processing apparatus is configured by a microprocessor, and includes a CPU 100, a ROM 101 that stores various control programs, and a RAM 102 that is a work memory for control data. The controller 100 of the motor 40 is connected to the CPU 100. The motor 40 includes a motor body 105 and an encoder 106 directly connected to the motor body 105. The controller 103 includes a counter 104 that counts pulses generated from the encoder 106. The controller 103 performs drive control of the servo motor according to the progress of the encoder pulse read by the counter 104. The controller 103 outputs a drive current value to be supplied to the CPU 100 according to the motor drive of the motor body 105. Further, external outputs from the angle detection sensor 112, the timer 113, and the like can be input to the CPU 100 via the interface 111. Further, input data of the key setting means 108 can be input to the CPU 100 via the interface 107, and various data can be displayed on the display 108 via the interface 109.

A striker rotation drive control process using the striker rotation type electric spark generating mechanism having the above configuration will be described below.
The rotation control device according to the present invention includes a CPU 100 and an execution process of striker rotation drive control executed by the CPU 100.

FIG. 7 shows a basic flowchart of the striker rotation drive control according to the present invention.
The striker rotation drive control is first performed after setting a reversal condition that defines the striker separation timing after contact (step S1). The inversion condition can be set using the key setting means 108. When the plasma processing is started, the motor 40 is normally rotated to move the striker arm from the stand-by standby state to the turning operation (steps S2 and S3). As the rotation of the striker proceeds, the striker tip 35 comes into contact with the cathode 2. Further, the motor 40 continues to be driven and the rotation operation continues. When the reversal condition is established, the motor 40 is instructed to perform reverse rotation, and the operation shifts to a separation operation that separates the striker chip 35 from the cathode 2, and when returning to the standby position, the drive of the motor 40 is stopped (steps S4 to S6).

FIG. 8 shows the striker drive control process of the torque change amount (differential change amount) management method in this embodiment. In the torque change amount management method, the differential change value of the motor torque is sequentially measured at a constant time interval (for example, 1 second) from the change in the drive current value of the motor 40. To set the initial specified value D ₀ of the motor torque change amount as an inverted condition (step S11). In this embodiment, carried out from time to time update process to continue updating the specified value Di to the upper limit value from the initial predetermined value D _0. When the plasma processing is started, the motor 40 is normally rotated and the striker arm moves from the stand-by standby state to the turning operation (steps S12 and S13). At this time, sequential measurement of the torque change amount is started, and the sequential measurement is repeated at regular intervals until the striker drive is stopped. Next, it is determined whether or not the torque change amount has reached a specified value. When the measured torque change amount exceeds the specified value, the number of continuous times is counted (step S16). When the measured torque change amount exceeds the specified value three times in succession, the motor 40 is instructed to drive in reverse as the inversion condition is satisfied, and the operation shifts to a separation operation in which the striker chip 35 is separated from the cathode 2. When returning to the standby position, the driving of the motor 40 is stopped (steps S17 to S19).

  According to the torque change amount management system, the torque change amount (differential change amount) per unit time from the start of the rotation of the striker arm is sequentially extracted and measured, and the torque change amount exceeding a predetermined specified value is 3 It is determined that the reversal condition is satisfied when the measurement is continuously performed more than the number of times. Therefore, even if the amount of torque change is detected due to the influence of disturbance noise caused by some cause, it will be excluded as a result of noise unless the amount of torque change exceeding the specified value is continuously measured three times or more. It is possible to prevent malfunction when the torque is set as the inversion condition. In particular, the torque change amount is obtained by measuring the current value of the rotational drive source motor, so that the differential change amount of the torque per minute time can be stably and precisely determined to accurately grasp the inversion condition, and the striker The contact action can be accurately performed over a long period of time.

Update processing will from time to time update process specified value Di to the upper limit value from the initial predetermined value D ₀ is performed in step S20～S21. When setting the torque as the reversal condition, it is difficult to sufficiently predict and determine the change over time due to long-term operation, even if the specified value is determined in advance based on experience values, etc. To correct as needed. In other words, when the excess measurement is not performed three times continuously but is performed four times discontinuously instead of three times continuously, the excess ΔD is added to the specified value Di at that time, and a new The specified value is stored and updated in the RAM 102 (step S14). The excess ΔD to be added is determined by selecting the maximum value among a plurality of detected values. Note that a predetermined fixed addition value may be used for the excess ΔD.

  According to the specified value update process, when the torque change amount exceeding the specified value is measured and the torque change amount exceeds the specified number of times 4 until the reversal condition is satisfied, When a situation occurs in which the amount of torque change exceeding the specified value is measured because the specified value with the value added is updated as a new specified value, and the reversal condition is determined based on the specified value. In addition, the specified value obtained by adding the excess amount of the torque change amount can be updated as a new specified value so as to follow the change with time, and the establishment of the reversal condition can be determined with higher accuracy over a longer period.

  Focusing on the fact that the abnormality detection related to the torque abnormality can be detected by measuring the torque change amount, an alarm process is added to the specified value update process. That is, it is determined whether or not the updated specified value has reached the upper limit value (step S22), and when it is determined that the updated specified value has reached the upper limit value, an alarm sound is generated by a buzzer (not shown). An alarm is generated by a warning display on the display 108 screen. Therefore, without updating the specified value more than necessary, it is possible to notify the alarm of the possibility of device abnormality or trouble by reaching the upper limit value, improving the safety of the striker type plasma generator and long-term Contributes to maintaining and promoting stable operation.

Examples of striker rotation drive control according to various inversion conditions are shown below. FIG. 9 shows a timer monitoring type striker drive control process.
The timer monitoring system, the drive control is performed based on the time measured by the timer 113, and sets the upper limit value T ₀ of the rotation duration from the rotation start as an inverted condition (step S41). The upper limit value T ₀ is determined by adding 1 second to the average value of the duration time when it is determined that the target is consumed at the time when it is rotated over 90 ° on average. When the plasma processing is started, the servo motor 40 is driven to rotate forward, and the striker arm shifts from the stand-by standby state to the turning operation (steps S42 and S43). Then, after blocking the overload working torque limiter 41 (step S44), turning the duration of the timer 113 it is determined whether reaches the set time T _0, the inverted condition upon reaching the set time T ₀ As a result, the servo motor 40 is instructed to perform reverse rotation, the operation shifts to a separation operation for separating the striker chip 35 from the cathode 2, and the drive of the servo motor 40 is stopped when returning to the standby position (steps S45 to S47). The torque limiter 41 is suitable as a load limiting means capable of instantaneously interrupting the torque overload of the electric motor. By providing the torque limiter 41 on the output shaft 36, the burden of the motor torque can be reliably ensured until the inversion condition is satisfied. Since this can be eliminated, the stable operation of the plasma generation mechanism can be maintained and the life can be extended.

According to the timer monitoring method, the inversion condition is established based on the fact that the time measured by the timer 113 reaches the set time T ₀ after the time limit judging means corresponding to steps S45 and S46 has shut off by the torque limiter 41. Therefore, the elapsed time from the start of the rotation of the striker 5 can be monitored by a timer to accurately grasp the inversion condition, and the contact action by the striker 5 can be stably performed over a long period of time.

FIG. 10 shows the striker drive control process of the striker rotation angle detection method.
In the striker rotation angle detection method, as shown in FIG. 3, drive control is performed based on the output of the angle detection sensor 112 disposed on the right side of the striker arm standing-by standby position, and from the striker arm standing-by standby position as an inversion condition. The rotation angle _A0 is set (step S31). The installation position of the angle detection sensor 112 is set slightly to the right from the striker arm standing-by standby position. As in the case of FIGS. 8 and 9, when the plasma process is started, the motor 40 is driven to rotate in the forward direction, and the striker arm moves from the stand-by standby state to the turning operation (steps S32 and S33). Then, after blocking the overload working torque limiter 41 (step S34), the setting rotational whether reaches the angle A ₀ is determined, it is determined that the inverted condition is satisfied when it reaches the A _0, The motor 40 is instructed to perform reverse rotation, and the operation shifts to a separation operation in which the striker chip 35 is separated from the cathode 2, and when returning to the standby position, the drive of the servo motor 40 is stopped (steps S35 to S37).

  According to the striker rotation angle detection method, after the interruption by the torque limiter 41 occurs by the rotation angle determination means corresponding to steps S35 and S36, the measured rotation angle based on the output of the angle detection sensor 112 becomes the set angle. When the rotation condition is reached, it is determined that the reversal condition is satisfied. Therefore, by measuring the rotation angle from the start of the rotation of the striker 5 with the angle detection sensor, the reversal condition is accurately grasped, and the contact action by the striker 5 is prolonged. It can carry out stably over this. As the angle detection sensor, a magnetic sensor, a contact sensor, or the like can be used in addition to the optical sensor that detects the displacement of the striker arm.

  In the plasma processing apparatus of FIG. 1, molybdenum is used for the striker arm material. Therefore, compared to the conventional SUS arm, it has a high heat resistance and a high Young's modulus, and because it uses a striker arm made of a high melting point material, it can suppress the formation of precipitates due to the high temperature accompanying arc discharge. High quality plasma generation can be performed. Furthermore, in the molybdenum arm, the arm amplitude generated during the hammering operation in which the striker 5 is brought into contact with the cathode 2 is reduced, and the controllability of the initial discharge by the striker 5 can be improved.

  The present invention is not limited to the above-described embodiments and modifications, and includes various modifications and design changes within the technical scope without departing from the technical idea of the present invention. Needless to say.

  According to the present invention, a striker-type plasma generator capable of stably performing a contact action by a striker over a long period of time, making the target material available to the maximum and realizing high quality of the generated plasma. Can be provided. In addition, according to the plasma processing apparatus of the present invention, the striker type plasma generator is mounted, stable operation can be realized, and plasma processing with high quality plasma can be performed, so that the surface of the solid material in the plasma is defective. By forming a high-purity thin film with significantly less impurities and irradiating with plasma, the surface characteristics of the solid can be uniformly modified without imparting defects or impurities. It is possible to provide a plasma processing apparatus capable of forming a wear / corrosion resistance enhanced film, a protective film, an optical thin film, a transparent conductive film, and the like with high quality and high accuracy.

DESCRIPTION OF SYMBOLS 1 Plasma generator 2 Cathode 3 Anode 4 Plasma generating part 5 Striker 6 Plasma traveling path 7 Bending part 8 Bending magnetic field generator 9 Dopplet traveling path 10 Droplet collecting part 11 Baffle 12 Baffle 13 Expanded tube 14 Magnetic field generator 15 Plasma Processing unit 16 Object to be processed 17 Baffle 18 Magnetic field generator 19 Baffle 20 Magnetic field generator 21 Target coil 22 Filter coil 23 Diameter reduction tube 24 Rotating shaft 25 Power supply 26 Current supply 27 Current supply 28 Anode inner wall 29 Outer wall 30 Insulating member 31 Insulating member 32 Discharge surface 33 Pipe end 34 Gap 35 Striker tip 36 Output shaft 37 Arc power supply 38 Protrusion 39 Hole 40 Motor 41 Torque limiter 42 Fixing part 100 CPU
101 ROM
102 RAM
103 Controller 104 Counter 105 Motor body 106 Encoder 107 Interface 108 Key setting means 109 Interface 110 Display 111 Interface 112 Angle detection sensor 113 Timer 200 Plasma generator 201 Arc power source 202 Cathode 203 Target 204 Strike 205 Rotating shaft 206 Plasma 207 Curved type Magnetic field duct 208 Straight type magnetic field duct 209 Plasma processing chamber 210 DC power source 211 DC power source 212 Stage 213 Object 214 DC power source 215 High frequency power source 216 Exhaust pump P Plasma B1 Stabilizing magnetic field B2 Plasma traveling magnetic field

Claims (13)

A plasma constituent material supply source is a cathode, an anode is provided in front of or around the cathode, and the tip of an arm pivotally supported by a rotary drive source is brought into contact with the supply source to generate arc discharge. A striker, and a rotation control device that controls the rotation of the rotation drive source in a direction in which the striker is brought into contact with or separated from the supply source, and arc plasma is generated between the cathode and the anode by the occurrence of the arc discharge. In the plasma generator to be operated, when the tip is brought into contact with the supply source by the rotation of the arm, the rotation control device is configured until the reversal condition in which a load applied to the striker exceeds a predetermined amount is satisfied. It comprises rotation control means that continues to rotate in the contact direction and reversely rotates the arm in the separation direction when the inversion condition is satisfied. Plasma generating apparatus. When an overload occurs in the output shaft of the rotational drive source, a torque limiter for interrupting transmission of torque to the arm is provided in the output shaft, and time measuring means for measuring the rotation continuation time from the start of rotation of the arm And the rotation control means has a time elapse judging means for judging that the reversal condition is satisfied based on a time measured by the time measuring means reaching a predetermined time after the torque limiter interrupts. The plasma generator according to claim 2. When the output shaft of the rotation drive source is overloaded, a torque limiter that cuts off the transmission of torque to the arm is provided on the output shaft, and an angle measuring unit that measures a rotation angle from the start of rotation of the arm The rotation control means is a rotation angle determination means for determining that the reversal condition is satisfied based on a measurement angle by the angle measurement means reaching a predetermined angle after the interruption by the torque limiter has occurred. The plasma generator of Claim 2 which has these. Torque change amount measuring means for sequentially extracting and measuring a torque change amount per unit time from the start of rotation of the arm is provided, and the rotation control means has a predetermined torque change amount exceeding a predetermined value. The plasma generator according to claim 1, further comprising a torque change amount determination unit that determines that the reversal condition is satisfied when measured continuously for a number of times. The rotation control means is configured to measure the torque change amount exceeding a predetermined specified value until the reversal condition is satisfied, and when the number of times the torque change amount exceeds the specified number, the torque change amount is exceeded. 5. The plasma generating apparatus according to claim 4, further comprising defined value update processing means for updating a defined value with a minute added as a new defined value and determining whether the inversion condition is satisfied based on the defined value. The rotation control means generates an alarm when determining that the updated specified value has reached the upper limit, and an upper limit reaching determination means for determining whether the updated specified value has reached an upper limit. The plasma generating apparatus according to claim 5, further comprising an alarm generating means. The plasma generator according to claim 4, 5 or 6, wherein the torque change amount measuring means comprises motor current measuring means for obtaining a torque change amount by measuring a current value of the rotation drive source motor. The plasma generator according to any one of claims 1 to 7, wherein a material of the arm is formed of a heat-resistant metal material having higher heat resistance than stainless steel material. The plasma generator according to any one of claims 1 to 7, wherein a material of the arm is formed of a metal material having a Young's modulus higher than that of a stainless steel material. The plasma generating apparatus according to claim 8 or 9, wherein the material of the arm is made of molybdenum, tungsten, titanium, inconel, or a heat resistant alloy composed of two or more of these. The shaft end of the output shaft is attached to a fitting hole formed at one end of the arm to connect the arm and the output shaft, and the cross-sectional shape of the fitting hole and the shaft end is made non-circular. The plasma generator in any one of Claims 1-10. The plasma generating apparatus according to any one of claims 1 to 11, wherein a retaining engagement portion that engages with each other is formed at an intermediate portion of each of the fitting hole and the shaft end portion in the axial direction. The plasma generator according to any one of claims 1 to 12, a plasma transport pipe for transporting plasma generated by the plasma generator, and a workpiece to be processed by the plasma supplied from the plasma transport pipe A plasma processing apparatus having a plasma processing unit.

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