JP2008210599A - Plasma processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a state of plasma with a simple structure while avoiding contamination. <P>SOLUTION: The plasma processing device includes: a high frequency power supply 2; a plasma generating part 4a; a directional coupler 3a; a matching unit body 3c; a matching unit control part 3e and a general control part 7 which matches impedance between the high frequency power supply 2 and the plasma generating part 4a by changing positions of slag 13, 14 based on a travelling wave Sf and a reflected wave Sr; and a memory part 8 which memorizes information about input impedance Z of the directional coupler 3a as extinction information D3 at the respective positions of the slag 13, 14 in a state in which plasma is not generated in the plasma generating part 4a. The general control part 7 determines a plasma generating state in the plasma generating part 4a by comparing input impedance Z computed based on the travelling wave Sf and the reflected wave Sr output form the directional coupler 3a with the extinction information D3 memorized in the memory part 8. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus configured to be able to determine the generation state of plasma.

As this type of plasma processing apparatus, a plasma processing apparatus disclosed in Japanese Patent Application Laid-Open No. 7-41954 is known. This plasma processing apparatus includes a discharge potential / current detection means for detecting a discharge potential and a discharge current in a vacuum vessel, a pressure measuring means for measuring a discharge pressure in the vacuum vessel, and a discharge power measurement for measuring the discharge power in the vacuum vessel. And means for comparing the magnitudes of changes in the detected values of the discharge potential / current, discharge pressure, and discharge power by each of these means, and the detected value is monitored, and the source gas according to the comparison result by the comparing means And a control device for performing microwave introduction control. In this plasma processing equipment, when the plasma discharge stops, the current and voltage in the discharge space become zero, the discharge pressure decreases, and the microwave power consumed so far increases. The discharge potential / current detection means, the pressure measurement means, and the discharge power measurement means detect the change in each state, and the comparison means stops the plasma discharge according to the magnitude of the change detected by each means. Detect whether or not. Further, in this plasma processing apparatus, a detection rod made of a conductor is disposed in a vacuum vessel, and a current detection means (ammeter) and a discharge potential detection means (voltmeter) are connected to the detection rod, respectively.
Japanese Patent Laid-Open No. 7-41954 (2nd page, FIG. 1)

  However, this conventional plasma processing apparatus has the following problems. That is, in this plasma processing apparatus, since the detection rod is disposed in the vacuum vessel, the phenomenon that the material constituting the detection rod is decomposed by the plasma generated in the vacuum vessel and adheres to the processing object (contamination). Has occurred, and there is a problem that the object to be processed may be contaminated. In order to avoid this problem, for example, a method of optically measuring the plasma state by providing an optical device outside the vacuum vessel can be considered, but it is necessary to provide an observation window in the vacuum vessel. Another problem is that the structure of the vacuum vessel is complicated.

  The present invention has been made in view of such problems, and a main object of the present invention is to provide a plasma processing apparatus capable of detecting a plasma state with a simple configuration while avoiding contamination.

  In order to achieve the above object, a plasma processing apparatus according to claim 1, wherein a high-frequency power source that outputs a high-frequency signal, a plasma generator that generates plasma by inputting the high-frequency signal, the high-frequency power source and the plasma generator A directional coupler that detects a traveling wave component signal and a reflected wave component signal of the high-frequency signal output from the high-frequency power source and disposed between the directional coupler and the plasma generator. And a matching unit body for matching impedance between the high-frequency power source and the plasma generation unit by changing a position of a built-in matching element, and based on the traveling wave component signal and the reflected wave component signal By changing the position of the matching element, the impedance between the high-frequency power source and the plasma generator is matched. A plasma processing apparatus including a control unit, wherein information about input impedance of the directional coupler at each position of the matching element in a state where the plasma is not generated in the plasma generation unit A storage unit that stores information, and the control unit includes an input impedance of the directional coupler calculated based on the traveling wave component signal and the reflected wave component signal output from the directional coupler; The generation state of the plasma in the plasma generation unit is determined by comparing the information at the time of plasma extinction stored in the storage unit.

  The plasma processing apparatus according to claim 2 is provided between a high frequency power source that outputs a high frequency signal, a plasma generation unit that receives the high frequency signal to generate plasma, and the high frequency power source and the plasma generation unit. A directional coupler that detects a traveling wave component signal and a reflected wave component signal for the high-frequency signal output from the high-frequency power source, and is disposed between the directional coupler and the plasma generator. A matching unit body that matches impedance between the high-frequency power source and the plasma generation unit by changing a position of a built-in matching element, and the matching element based on the traveling wave component signal and the reflected wave component signal A control unit that changes the position to match impedance between the high-frequency power source and the plasma generation unit. A storage device for storing information on input impedance of the directional coupler at each position of the matching element in a state where the plasma is generated in the plasma generation unit as plasma generation time information The control unit includes an input impedance of the directional coupler calculated based on the traveling wave component signal and the reflected wave component signal output from the directional coupler, and the storage unit The plasma generation state in the plasma generation unit is determined by comparing the stored plasma generation time information.

  According to a third aspect of the present invention, in the plasma processing apparatus according to the first or second aspect, after the control unit determines that the plasma is generated in the plasma generation unit, the plasma generation unit When it is determined that the plasma has been extinguished, the high-frequency power supply is controlled to stop the output of the high-frequency signal.

  In the plasma processing apparatus according to claim 1, information about the input impedance of the directional coupler at the position of the matching element in a state where no plasma is generated in the plasma generation unit is stored in advance in the storage unit as information at the time of plasma extinction. The control unit inputs the directional coupler input impedance calculated based on the traveling wave component signal and the reflected wave component signal output from the directional coupler, and the plasma extinction information stored in the storage unit. When the input impedance is included in the plasma extinction information range, the plasma is stopped, and when the input impedance is out of the plasma extinction information range, the plasma is generated (ignition It is determined that this is a Therefore, according to this plasma processing apparatus, it is not necessary to dispose the detection rod in the region where the plasma is generated, so that contamination can be avoided reliably and plasma is generated in the plasma processing chamber. In this case, since it is not necessary to provide an observation window in the plasma processing chamber, the structure of the plasma processing apparatus can be easily configured.

  In the plasma processing apparatus according to claim 2, information on the input impedance of the directional coupler at the position of the matching element in a state where plasma is generated in the plasma generation unit is stored in advance in the storage unit as plasma generation time information. The control unit inputs the directional coupler input impedance calculated based on the traveling wave component signal and the reflected wave component signal output from the directional coupler, and the plasma generation time information stored in the storage unit, When the input impedance is included in the plasma generation information range, the plasma is in the generated state (ignition state), and the input impedance is out of the plasma generation information range. It is determined that the plasma is stopped. Therefore, according to this plasma processing apparatus, it is not necessary to dispose the detection rod in the region where the plasma is generated, so that contamination can be avoided reliably and plasma is generated in the plasma processing chamber. In this case, since it is not necessary to provide an observation window in the plasma processing chamber, the structure of the plasma processing apparatus can be easily configured.

  According to the plasma processing apparatus of claim 3, after the ignition of the plasma, when it is determined that the plasma is extinguished, the control unit controls the high frequency power supply to stop the output of the high frequency signal, so that the high frequency signal is wasted. As a result, the power supply efficiency and safety of the plasma processing apparatus can be sufficiently improved.

  Hereinafter, the best mode of a plasma processing apparatus according to the present invention will be described with reference to the accompanying drawings.

  A plasma processing apparatus 1 shown in FIG. 1 includes a high-frequency power source 2, a matching unit 3, a plasma processing chamber 4, a gas supply device 5, a gas exhaust device 6, an overall control unit 7, a storage unit 8, and an output unit 9. The plasma processing apparatus 1 generates a plasma in the plasma processing chamber 4 by supplying a high-frequency signal (for example, a microwave) S generated by the high-frequency power source 2 to the plasma processing chamber 4 via the matching unit 3. The plasma processing chamber 10 is configured to be able to perform plasma processing on the workpiece 10 accommodated in the plasma processing chamber 4.

  As shown in FIG. 1, the high-frequency power source 2 includes a high-frequency control unit 2 a and a high-frequency generation unit 2 b, generates a high-frequency signal (for example, a microwave of about 2.45 GHz) S as a continuous wave, and the matching unit 3 Output to. Specifically, the high frequency control unit 2a operates the high frequency generation unit 2b to output the high frequency signal S when the control signal S1 is input from the overall control unit 7. On the other hand, when the input of the control signal S1 from the overall control unit 7 is stopped, the high frequency control unit 2a stops the operation of the high frequency generation unit 2b and stops the output of the high frequency signal S.

  As shown in FIG. 1, the matching unit 3 includes a directional coupler 3a, a detector 3b, a matching unit body 3c, a moving mechanism 3d, and a matching unit control unit 3e. The directional coupler 3a outputs the input high-frequency signal S to the matching unit main body 3c, detects a traveling wave and a reflected wave of the high-frequency signal S, and a traveling wave component signal (hereinafter referred to as a traveling wave component signal) corresponding to the traveling wave voltage. The reflected wave component signal (hereinafter also referred to as “reflected wave”) Sr having a voltage corresponding to Sf and the voltage of the reflected wave is output to the detector 3b. The detector 3b receives the traveling wave Sf and the reflected wave Sr, and detects the power Pf of the traveling wave Sf, the power Pr of the reflected wave Sr, and the phase difference θ between the traveling wave Sf and the reflected wave Sr. Output.

  For example, as shown in FIG. 2, the matching unit main body 3 c includes a tubular (cylindrical) outer conductor 11, and a cylindrical inner conductor 12 disposed in the outer conductor 11 so that the axes thereof coincide with each other. As a so-called slag tuner including two sets of dielectrics (matching elements in the present invention; slag as an example) 13 and 14 disposed in a gap between the inner surface of the outer conductor 11 and the outer surface of the inner conductor 12 It is comprised and is arrange | positioned between the directional coupler 3a and the plasma processing chamber 4. FIG. Further, one slit SL is formed in the outer conductor 11 along the longitudinal direction thereof. Further, the slag 13 on the input end side (left end side in FIG. 2) is connected to the slags 13a and 13b made of a dielectric material, and the moving bracket 13c connected to the slags 13a and 13b and moved by the moving mechanism 3d. And. In this case, the moving bracket 13c is inserted into the slit SL, and its end (upper end in FIG. 2) protrudes from the slit SL to the outside of the external conductor 11. Similarly to the slag 13, the slag 14 on the output end side (right end side in FIG. 2) connects the slags 14a and 14b made of a dielectric material and the slags 14a and 14b and is moved by the moving mechanism 3d. And a moving bracket 14c. In this case, the thickness L1 of each slag 13a, 13b, 14a, 14b is set to λ / 4 (λ is the in-pipe wavelength of the high-frequency signal S in the matching unit main body 3c), the interval L2 between the slags 13a, 13b and the slag 14a. , 14b is also set to λ / 4. Further, a parameter X in the figure indicates a distance between the slag 13 and the slag 14. The parameter Y indicates the distance between the intermediate point between the slag 13 and the slag 14 and the output reference point of the matching unit main body 3c (the right end of the external conductor 11). In the matching unit 3, the slags 13 and 14 are slid (moved) to change the positions of the slags 13 and 14, thereby changing the parameters X and Y, thereby enabling impedance matching.

  As illustrated in FIG. 2, the moving mechanism 3 d includes a moving mechanism 21 that moves the slag 13 and a moving mechanism 22 that moves the slag 14. The moving mechanism 21 includes a pair of pulleys 21a and 21b disposed in the vicinity of each end of the outer conductor 11, a wire rope 21c spanned between the pair of pulleys 21a and 21b, and a motor that rotationally drives the wire rope 21c. The moving bracket 13c of the slag 13 is connected to the wire rope 21c. With this configuration, when the wire rope 21c is rotationally driven by the motor 21d, the slug 13 slides in the outer conductor 11 together with the moving bracket 13c. On the other hand, the moving mechanism 22 includes a wire rope 22c spanned between a pair of pulleys 22a and 22b disposed in the vicinity of each end of the outer conductor 11, and a motor 22d that rotationally drives the wire rope 22c. The moving bracket 14c of the slag 14 is connected to the wire rope 22c. With this configuration, when the wire rope 22c is rotationally driven by the motor 22d, the slug 14 slides in the outer conductor 11 together with the moving bracket 14c.

  The matching unit control unit 3e constitutes a control unit in the present invention together with the overall control unit 7, and includes a CPU and an internal memory. The matching unit controller 3e outputs the output state of the high frequency signal S from the high frequency power source 2 (the high frequency signal S is output from the high frequency power source 2 based on the power Pf, the power Pr, and the phase difference θ output from the detector 3b. And whether the input impedance Z of the matching unit 3 is calculated in real time. The matching device controller 3e executes the impedance matching process when the control signal S2 is input from the overall controller 7. In this impedance matching process, while calculating the ratio (ratio) Dp (= Pr × 100 / Pf) of the power Pr to the power Pf, the moving mechanism 3d is controlled so that the ratio Dp becomes small, and each of the matching unit main bodies 3c is controlled. This is a process of sliding the slags 13 and 14 and moving the slags 13 and 14 to positions where the ratio Dp is minimum. In addition, the matching unit controller 3e has high frequency output information D1 indicating the output state of the determined high frequency signal S, the calculated input impedance Z, and position information D2 about each of the current slugs 13 and 14 in the matching unit main body 3c. Is output to the overall control unit 7.

  The plasma processing chamber 4 is configured so that the plasma generation unit 4a is disposed therein and the workpiece 10 can be accommodated. The plasma generator 4a receives the high frequency signal S and generates plasma. The gas supply device 5 operates when a control signal S3 is input from the overall control unit 7 to generate a gas for generating plasma and supply it into the plasma processing chamber 4. The gas exhaust device 6 operates when the control signal S4 is input from the overall control unit 7, and discharges the plasma generating gas in the plasma processing chamber 4 to the outside of the plasma processing chamber 4 by a predetermined amount.

  The overall control unit 7 includes a CPU and an internal memory. Further, the overall control unit 7 outputs these control signals S1, S2, S3, and S4 to the high frequency control unit 2a, the matching unit control unit 3e, the gas supply device 5, and the gas exhaust device 6 so that these components can be obtained. Control. Further, the overall control unit 7 uses the input impedance Z of the matcher 3 input from the matcher control unit 3e and the plasma extinction information D3 (hereinafter also referred to as “annihilation information D3”) stored in the storage unit 8. Based on this, a plasma state determination process for determining whether or not plasma is generated in the plasma processing chamber 4 is executed. The storage unit 8 includes a ROM and a RAM, and stores an operation program for the overall control unit 7 together with the disappearance information D3. The output unit 9 includes a display device as an example, and displays information according to the control signal S5 from the overall control unit 7.

  In this case, the extinction information D3 is a state in which a high frequency signal S is supplied from the high frequency power source 2 to the plasma processing chamber 4, but no plasma is generated in the plasma processing chamber 4 (for example, a low level high frequency signal). In the state where the signal S is supplied), while measuring the input impedance Z of the matching device 3, the slag 14 is gradually shifted from the output reference point of the external conductor 11 toward the input end, and at each position of the slag 14. The information about the input impedance Z of the matching device 3 measured at each position of the slags 13 and 14 when the slag 13 is in contact with the slag 14 and gradually shifted from the input end of the external conductor 11. In this example, the annihilation information D3 is, for example, the input impedance Z of the input impedance Z measured at each position of the slugs 13 and 14 in consideration of measurement errors and variations of the input impedance Z. It is set as range data of a predetermined width centered. For easy understanding, when the disappearance information D3 at one position of the slugs 13 and 14 is shown on the Smith chart, as shown in FIG. 4, the range including the input impedance Z measured at this one position. It is expressed as data (shaded area).

  Next, the operation of the plasma processing apparatus 1 according to the present invention will be described with reference to FIG.

  When the plasma processing apparatus 1 is operated, the overall control unit 7 first outputs control signals S3 and S4 to the gas supply apparatus 5 and the gas exhaust apparatus 6 to start the operation, and the control signal S1 is supplied to the high-frequency power source 2. The output is started and the operation of the high frequency power source 2 is started (step 51). In the matching unit 3, the directional coupler 3a starts detecting the traveling wave Sf and the reflected wave Sr, and the detector 3b uses the traveling wave Sf and the reflected wave Sr based on the traveling wave Sf and the reflected wave Sr. The process of detecting and outputting the power Pr of Sr and the phase difference θ between the traveling wave Sf and the reflected wave Sr is started. The matching unit controller 3e detects whether or not the high-frequency signal S is reliably output from the high-frequency power source 2 (output state of the high-frequency signal S) based on the power Pf of the traveling wave Sf (step 52). ), And starts the process of outputting the detection result to the overall control unit 7 as the high frequency output information D1.

  Next, when the overall control unit 7 determines that the high-frequency signal S is reliably output from the high-frequency power source 2 based on the content of the high-frequency output information D1 output from the matching unit control unit 3e, the overall control unit 7 outputs the control signal S5. Then, information indicating “plasma ignition” is displayed on the output unit 9 (step 53), and when it is determined that the high-frequency signal S is not output from the high-frequency power source 2, a control signal S5 is output to the output unit 9 Information indicating "plasma stop" is displayed (step 54).

  In this case, the overall control unit 7 repeatedly determines the content of the high-frequency output information D1 from the matching unit control unit 3e, and when the content indicates that the high-frequency signal S is not output, the high-frequency signal S is not output. Is detected for a specified time (for example, time T1) from the start of output of the control signal S1 to the high frequency power source 2 (step 55). As a result of this detection, when it is determined that the non-output state of the high-frequency signal S has continued for the specified time T1, the overall control unit 7 stops the output of the control signal S3 to the gas supply device 5, thereby causing the plasma processing chamber 4 to stop. Is stopped, and the control signal S5 is output to the output unit 9 to display alarm information (for example, “abnormality of the high frequency power supply 2”) (step 56), and this plasma generation process is terminated. As a result, the high-frequency signal S is not input to the matching unit 3 due to an abnormality in at least one of the high-frequency power source 2 and the signal line between the high-frequency power source 2 and the matching unit 3 even though the high-frequency power source 2 is operated. Is prevented from being left for a long time.

  Subsequently, the overall control unit 7 causes the output unit 9 to display information indicating “plasma ignition” in step 53, and then outputs a control signal S2 to the matching unit control unit 3e to perform impedance matching processing. Start (step 57). This impedance matching process is a matching process in a state where no plasma is generated in the plasma processing chamber 4, and the matching unit controller 3e sets the power Pf, the power Pr, and the phase difference θ output from the detector 3b. Based on this, the input impedance Z of the matching unit 3 is calculated in real time, and the ratio Dp of the electric power Pr to the electric power Pf is calculated to control the movement of the slugs 13 and 14 to the position where the ratio Dp is minimum. In addition, the matching unit controller 3e starts outputting the calculated input impedance Z and the positional information D2 about each of the current slugs 13 and 14 in the matching unit main body 3c to the overall control unit 7.

  Next, the overall control unit 7 inputs the input impedance Z and position information D2 of each of the slags 13 and 14 from the matching unit control unit 3e, and within the outer conductor 11 of each of the slags 13 and 14 specified by the input position information D2. The extinction information D3 corresponding to the current position is read from the storage unit 8 and it is detected whether or not the input impedance Z is included in the range of the read extinction information D3 (step 58). In this case, in a situation where the supply of the high frequency signal S from the high frequency power source 2 to the plasma processing chamber 4 is started, the matching unit controller 3e starts the impedance matching process, so that the input impedance Z of the matching unit 3 becomes a high frequency. Since the output impedance of the power source 2 is gradually matched, the power of the high-frequency signal S supplied to the plasma processing chamber 4 gradually increases. For this reason, when the plasma processing apparatus 1 is normal, the input impedance Z is included in the range of the extinction information D3 only for a short period immediately after the start of the supply of the high-frequency signal S from the high-frequency power source 2 to the plasma processing chamber 4. Before a specified time (for example, time T2) has elapsed from the start of the supply of the high frequency signal S to the chamber 4, the power of the high frequency signal S supplied to the plasma processing chamber 4 reaches the power required for ignition and the plasma is ignited. To do. As a result, the input impedance Z shifts outside the range of the disappearance information D3 (becomes a value outside the range) as shown by a black square in FIG. 4 before the lapse of the specified time T2.

  Therefore, in step 58, when the input impedance Z is within the range of the annihilation information D3, the overall control unit 7 determines that this state has started from the start of supply of the high frequency signal S to the plasma processing chamber 4 (specifically, “plasma Steps 57, 58, and 59 are repeatedly executed while determining whether or not the specified time T2 has continued (from the input of the high-frequency output information D1 having the content of “igniting”) (step 59). As a result, in step 59, when the state where the input impedance Z is within the range of the disappearance information D3 continues for the specified time T2, the overall control unit 7 determines that an abnormality has occurred in the plasma processing apparatus 1, The output of the control signal S1 to the high frequency power source 2 is stopped to stop the operation (output of the high frequency signal S), and the output of the control signal S3 to the gas supply device 5 is stopped to supply the gas to the plasma processing chamber 4 Stop. The overall control unit 7 stops the output of the control signal S2 to the matching unit control unit 3e to end the impedance matching process, and outputs a control signal S5 to the output unit 9 to output alarm information (for example, “plasma process”). "Abnormality of chamber 4") is displayed (step 60), and this plasma generation process is terminated.

  On the other hand, when it is detected in step 58 that the input impedance Z has shifted outside the range of the extinction information D3 before reaching the specified time T2, the overall control unit 7 ignites (generates) plasma in the plasma processing chamber 4. ) (Discharge is started), and the control signal S5 is output to the output unit 9, so that information indicating that the plasma in the plasma processing chamber 4 is in a generated state (for example, “being generated”) Character) is displayed on the output unit 9 (step 61). The input impedance of the plasma processing chamber 4 changes due to the start of plasma generation, and the input impedance Z of the matching unit 3 also changes due to this, but in the matching unit 3, the matching unit control unit 3e subsequently performs impedance matching. Since the processing is executed, even in the state where plasma is generated in the plasma processing chamber 4, the input impedance Z of the matching unit 3 is gradually matched with the output impedance of the high-frequency power source 2, and the plasma processing chamber 4 is supplied to the plasma processing chamber 4. The high-frequency signal S is supplied efficiently.

  Thereafter, the overall control unit 7 repeatedly executes the same operation as in step 58, so that the input impedance Z output from the matching unit control unit 3e is included again in the range of the extinction information D3 read from the storage unit 8. Is detected (step 62). As a result of this detection, when the input impedance Z is included again within the range of the extinction information D3, the overall control unit 7 determines that the plasma in the plasma processing chamber 4 has disappeared for some reason, and the control signal S5 Is output to the output unit 9, information indicating that the plasma in the plasma processing chamber 4 has been extinguished (for example, “plasma stop”) is displayed on the output unit 9 (step 63). Next, the overall control unit 7 determines whether or not the re-ignition is set for the plasma processing apparatus 1 (step 64). When re-ignition is permitted, the overall control unit 7 proceeds to step 52. Then, the plasma generation process is executed again. On the other hand, when reignition is not permitted, the above-described step 60 is executed, and then the plasma generation process is terminated. In this manner, when the plasma is ignited and then extinguished, the generation of the high-frequency signal S by the high-frequency power source 2 is stopped by the overall control unit 7, so that the situation where the high-frequency signal S is continuously output is avoided. The power supply efficiency and safety of the plasma processing apparatus 1 are sufficiently enhanced.

  As described above, in this plasma processing apparatus 1, the input impedance Z of the matching device 3 (that is, the input of the directional coupler 3a) at each position of each slag 13 and 14 in a state where no plasma is generated in the plasma processing chamber 4. Information on the impedance) is previously stored in the storage unit 8 as the disappearance information D3, and the overall control unit 7 performs the matching unit control unit 3e based on the traveling wave Sf and the reflected wave Sr output from the directional coupler 3a. The calculated input impedance Z and the extinction information D3 stored in the storage unit 8 are compared. When the input impedance Z is included in the range of the extinction information D3, the plasma is in a stopped state, and the input When the impedance Z is out of the range of the extinction information D3, it is determined that the plasma is generated (ignited). Therefore, according to this plasma processing apparatus 1, unlike the conventional configuration, it is not necessary to dispose the detection rod in the plasma processing chamber 4, so that contamination can be reliably avoided and the plasma processing chamber 4 Since it is not necessary to provide an observation window, the structure of the plasma processing chamber 4 and thus the structure of the plasma processing apparatus 1 itself can be easily configured.

  Further, according to the plasma processing apparatus 1, the overall control unit 7 controls the high-frequency power source 2 to stop the output of the high-frequency signal S when it is determined that the plasma has disappeared after the ignition of the plasma. As a result of reliably avoiding the situation where the high-frequency signal S continues to be output unnecessarily, the power supply efficiency and safety of the plasma processing apparatus 1 can be sufficiently improved.

  The present invention is not limited to the configuration shown in the above embodiment. For example, in the above embodiment, the slag 13, which is measured in a state where the high frequency signal S is supplied from the high frequency power source 2 to the plasma processing chamber 4 but no plasma is generated in the plasma processing chamber 4, Although generation | occurrence | production (ignition) and stop (extinction) of a plasma are discriminate | determined using the extinction information D3 which is the information about the input impedance Z of the matching device 3 in each of 14 positions, it is not limited to this. For example, information about the input impedance Z of the matching unit 3 (that is, the input impedance of the directional coupler 3a) at each position of each of the slugs 13 and 14 in a state where plasma is generated in the plasma processing chamber 4 is generated when the plasma is generated. Information (hereinafter referred to as ignition information D4) is stored in the storage unit 8 in advance, and when the overall control unit 7 includes the input impedance Z within the range of the ignition information D4, plasma is generated and the input impedance It is also possible to adopt a configuration in which it is determined that the plasma is in a stopped state when Z is out of the range of the ignition information D4. Also in this configuration, since it is not necessary to arrange the detection rod in the plasma processing chamber 4, contamination can be avoided reliably, and it is not necessary to provide an observation window in the plasma processing chamber 4. Thus, the structure of the plasma processing apparatus 1 itself can be easily configured.

  However, the state of the plasma generated in the plasma processing chamber 4 depends on the type of gas supplied from the gas supply device 5 to the plasma processing chamber 4, the gas supply pressure (flow rate per unit time), and the high-frequency signal S. Therefore, the input impedance of the plasma processing chamber 4 and thus the input impedance Z of the matching unit 3 are also changed. For this reason, the ignition information D4 has a huge amount of information. On the other hand, since the extinction information D3 is information when plasma is not generated in the plasma processing chamber 4, the amount of information is small. Therefore, as compared with the configuration using the ignition information D4, the configuration using the extinction information D3 can significantly reduce the time and cost required for data acquisition, thereby sufficiently reducing the apparatus cost. Can do.

  Further, as the above-described extinction information D3 and ignition information D4, information about the input impedance Z of the matching unit 3 measured at each position of the slags 13 and 14 is used. It is also possible to measure the input impedance Z when the parameters X and Y are changed, and use information in which the values of the parameters X and Y correspond to the measured input impedances Z. Further, the input impedance Z of the matching device 3 is used as the extinction information D3 and the ignition information D4 described above, but the ratio Dp of the power Pr to the power Pf and the phase difference between the traveling wave Sf and the reflected wave Sr. Since θ is also a parameter that substantially indicates the input impedance Z, it is needless to say that the ratio Dp and the phase difference θ may be used.

  Moreover, although the structure which arrange | positions the matching device control part 3e and the integrated control part 7 separately was employ | adopted, the structure which includes the function of the matching machine control part 3e in the integrated control part 7, and abbreviate | omits the matching machine control part 3e Can also be adopted. In addition, the moving mechanism 3d may be configured using a timing belt, a steel belt, a V belt, a flat belt, a gear (rack and pinion), etc., instead of the wire ropes 21c and 22c. Further, the moving mechanism can be configured using a ball screw or the like without using belts. In addition, the matching unit 3 configured using the matching unit body 3c including the slag 13 having the pair of slags 13a and 13b and the slag 14 having the pair of slags 14a and 14b has been described as an example. The configuration of the device 3 is not limited to this, and a matching device 3 having another configuration can also be used.

  Further, the configuration in which the plasma generation unit 4a is disposed in the plasma processing chamber 4 (for example, a chamber) and the workpiece 10 is processed in the plasma processing chamber 4 has been described above. However, instead of this configuration, a plasma torch is used. It is also possible to employ a configuration in which the workpiece 10 is processed by generating plasma in the atmosphere. In this configuration, in order to confirm the generation of plasma, conventionally, an observation window is provided at a point close to the plasma location inside the plasma torch, or the processing object 10 is ejected from the plasma torch by placing it in a dark place. Optical methods such as a method of detecting the light of the ejected plasma while treating with the plasma are generally adopted, but the method of providing the observation window is electrically affected and However, there is a problem that the processing environment is limited with respect to the method of detecting the light of the generated plasma. However, by adopting the present invention, it is possible to reliably detect the generation of plasma while avoiding the occurrence of these problems even in a configuration using a plasma torch.

1 is a configuration diagram of a plasma processing apparatus 1. FIG. It is side surface sectional drawing of the matching device main body 3c, and the side view of the moving mechanism 3d. 4 is a flowchart for explaining plasma generation processing by the plasma processing apparatus 1. It is a Smith chart for demonstrating the outline | summary of the extinction information D3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 2 High frequency power supply 3 Matching device 3a Directional coupler 3c Matching device main body 3e Matching device control part 4 Plasma processing chamber 4a Plasma generation part 7 General control part 8 Memory | storage part 13,14 Slag D3 Extinction information D4 Ignition information S High-frequency signal Sf Traveling wave Sr Reflected wave Z Input impedance θ Phase difference

Claims (3)

A high-frequency power source that outputs a high-frequency signal;
A plasma generator for generating plasma by inputting the high-frequency signal;
A directional coupler that is disposed between the high-frequency power source and the plasma generator and detects a traveling wave component signal and a reflected wave component signal for the high-frequency signal output from the high-frequency power source;
A matching unit body which is arranged between the directional coupler and the plasma generation unit and matches the impedance between the high-frequency power source and the plasma generation unit by changing a position of a built-in matching element;
A plasma processing apparatus comprising: a control unit that changes the position of the matching element based on the traveling wave component signal and the reflected wave component signal to match impedance between the high-frequency power source and the plasma generation unit. And
A storage unit for storing information on the input impedance of the directional coupler at each position of the matching element in a state where the plasma is not generated in the plasma generation unit as plasma extinction information;
The control unit stores an input impedance of the directional coupler calculated based on the traveling wave component signal and the reflected wave component signal output from the directional coupler, and the storage unit. A plasma processing apparatus for determining a generation state of the plasma in the plasma generation unit by comparing the information at the time of extinction of the plasma. A high-frequency power source that outputs a high-frequency signal;
A plasma generator for generating plasma by inputting the high-frequency signal;
A directional coupler that is disposed between the high-frequency power source and the plasma generator and detects a traveling wave component signal and a reflected wave component signal for the high-frequency signal output from the high-frequency power source;
A matching unit body which is arranged between the directional coupler and the plasma generation unit and matches the impedance between the high-frequency power source and the plasma generation unit by changing a position of a built-in matching element;
A plasma processing apparatus comprising: a control unit that changes the position of the matching element based on the traveling wave component signal and the reflected wave component signal to match impedance between the high-frequency power source and the plasma generation unit. And
A storage unit for storing information about the input impedance of the directional coupler at each position of the matching element in a state where the plasma is generated in the plasma generation unit as plasma generation time information;
The control unit stores an input impedance of the directional coupler calculated based on the traveling wave component signal and the reflected wave component signal output from the directional coupler, and the storage unit. A plasma processing apparatus for discriminating a generation state of the plasma in the plasma generation unit by comparing the information at the time of plasma generation.   The controller, after determining that the plasma is generated in the plasma generator, controls the high-frequency power source when determining that the plasma is extinguished in the plasma generator, and outputs the high-frequency signal. The plasma processing apparatus according to claim 1 or 2, which is stopped.

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