阅读说明：本技术 阻抗匹配装置、异常诊断方法以及存储介质
(Impedance matching device, abnormality diagnosis method, and storage medium
) 是由 加藤秀生 于 2020-04-01 设计创作，主要内容包括：本发明提供一种阻抗匹配装置、异常诊断方法以及存储介质,阻抗匹配装置对构成阻抗匹配装置的各部件的异常进行自我诊断,具有：可变电容元件,其连接在高频电源与负载之间；第一检测器,其检测用于判断高频电源与负载之间的阻抗匹配的指标值及表示从高频电源输入的高频的状态的第一状态值；第二检测器,其检测表示向负载输出的高频的状态的第二状态值；调整部,其逐步调整可变电容元件的电容值,以使由第一检测器检测出的指标值落在表示阻抗匹配完成的目标范围内；以及诊断部,其基于由调整部调整后的电容值、由第一检测器检测出的第一状态值以及由第二检测器检测出的第二状态值来对可变电容元件、第一检测器或第二检测器的异常进行诊断。(The present invention provides an impedance matching device, an abnormality diagnosis method, and a storage medium, wherein the impedance matching device performs self-diagnosis of abnormality of each component constituting the impedance matching device, and comprises: a variable capacitance element connected between a high-frequency power source and a load; a first detector that detects an index value for determining impedance matching between the high-frequency power supply and the load and a first state value indicating a state of a high frequency input from the high-frequency power supply; a second detector that detects a second state value indicating a state of a high frequency output to the load; an adjustment unit that adjusts the capacitance value of the variable capacitance element step by step so that the index value detected by the first detector falls within a target range indicating completion of impedance matching; and a diagnosis unit that diagnoses an abnormality of the variable capacitive element, the first detector, or the second detector based on the capacitance value adjusted by the adjustment unit, the first state value detected by the first detector, and the second state value detected by the second detector.)
1. An impedance matching device, having:
a variable capacitance element connected between a high-frequency power source and a load;
a first detector that detects an index value for determining impedance matching between the high-frequency power supply and the load and a first state value representing a state of a high frequency input from the high-frequency power supply;
a second detector that detects a second state value indicating a state of a high frequency output to the load;
an adjustment section that adjusts the capacitance value of the variable capacitance element step by step so that the index value detected by the first detector falls within a target range indicating completion of the impedance matching; and
and a diagnosis unit configured to diagnose an abnormality in the variable capacitive element, the first detector, or the second detector based on the capacitance value adjusted by the adjustment unit, the first state value detected by the first detector, and the second state value detected by the second detector.
2. The impedance matching device of claim 1,
the first detector detects a phase difference between a voltage and a current of a high frequency input from the high frequency power supply as the index value, and detects a power value of the high frequency input from the high frequency power supply as the first state value,
the second detector detects a power value of a high frequency output to the load as the second state value,
the adjusting section adjusts the capacitance value of the variable capacitance element step by step so that the phase difference detected by the first detector falls within the target range,
the diagnostic unit calculates a theoretical value of a high-frequency power value to be output to the load based on the capacitance value adjusted by the adjustment unit and the power value detected by the first detector, and determines that the abnormality has occurred when a difference between the calculated theoretical value of the power value and the power value detected by the second detector is equal to or greater than a predetermined threshold value.
3. The impedance matching device of claim 1,
the first detector detects a phase difference between a voltage and a current of a high frequency input from the high frequency power supply as the index value, and detects a power value of the high frequency input from the high frequency power supply as the first state value,
the second detector detects an amplitude value of a high-frequency voltage output to the load and an impedance value on the load side as the second state value,
the adjusting section adjusts the capacitance value of the variable capacitance element step by step so that the phase difference detected by the first detector falls within the target range,
the diagnostic unit calculates a theoretical value of the amplitude value of the high-frequency voltage based on the capacitance value of the variable capacitive element adjusted by the adjustment unit, the power value detected by the first detector, and the impedance value on the load side detected by the second detector, and determines that the abnormality has occurred when a difference between the calculated theoretical value of the amplitude value of the high-frequency voltage and the amplitude value of the high-frequency voltage detected by the second detector is equal to or greater than a predetermined threshold value.
4. An impedance matching device is provided with:
a variable capacitance element connected between a high-frequency power source and a load;
a detector that detects an index value for determining impedance matching between the high-frequency power supply and the load;
an adjustment section that adjusts the capacitance value of the variable capacitance element step by step so that the index value detected by the detector falls within a target range indicating completion of the impedance matching; and
and a diagnosis unit that monitors the number of times the capacitance value of the variable capacitance element is adjusted by the adjustment unit, that is, the number of times the capacitance value is adjusted, and diagnoses an abnormality in the variable capacitance element or the detector based on the number of times the capacitance value is adjusted and the index value detected by the detector.
5. The impedance matching device of claim 4,
the detector detects a phase difference between a voltage and a current of a high frequency input from the high frequency power supply as the index value,
the adjusting section adjusts the capacitance value of the variable capacitance element stepwise so that the phase difference detected by the detector falls within the target range,
the diagnostic unit determines that the abnormality has occurred when the number of times the capacitance value is adjusted reaches a predetermined number of times and the phase difference detected by the detector does not fall within the target range.
6. An abnormality diagnosis method is performed in an impedance matching apparatus, wherein,
the impedance matching device has:
a variable capacitance element connected between a high-frequency power source and a load;
a first detector that detects an index value for determining impedance matching between the high-frequency power supply and the load and a first state value representing a state of a high frequency input from the high-frequency power supply;
a second detector that detects a second state value indicating a state of a high frequency output to the load,
the abnormality diagnosis method includes the steps of:
gradually adjusting the capacitance value of the variable capacitance element so that the index value detected by the first detector falls within a target range indicating completion of the impedance matching; and
diagnosing an abnormality of the variable capacitive element, the first detector, or the second detector based on the adjusted capacitance value of the variable capacitive element, the first state value detected by the first detector, and the second state value detected by the second detector.
7. A computer-readable storage medium storing an abnormality diagnostic program that causes an impedance matching apparatus to execute steps in which,
the impedance matching device has:
a variable capacitance element connected between a high-frequency power source and a load;
a first detector that detects an index value for determining impedance matching between the high-frequency power supply and the load and a first state value representing a state of a high frequency input from the high-frequency power supply;
a second detector that detects a second state value indicating a state of a high frequency output to the load,
the abnormality diagnostic program causes the impedance matching device to execute steps including:
gradually adjusting the capacitance value of the variable capacitance element so that the index value detected by the first detector falls within a target range indicating completion of the impedance matching; and
diagnosing an abnormality of the variable capacitive element, the first detector, or the second detector based on the adjusted capacitance value of the variable capacitive element, the first state value detected by the first detector, and the second state value detected by the second detector.
Technical Field
The present disclosure relates to an impedance matching apparatus, an abnormality diagnosis method, and a storage medium.
Background
Conventionally, a plasma processing apparatus is known which performs a plasma process on an object to be processed such as a wafer by using plasma. Such a plasma processing apparatus has a stage for holding a target object, which also functions as an electrode, in a processing chamber that can form a vacuum space. The plasma processing apparatus applies a predetermined high frequency from a high frequency power source to the mounting table to perform a plasma process on the object to be processed mounted on the mounting table. An impedance matching device for performing impedance matching between the high-frequency power source and the processing chamber is disposed between the high-frequency power source and the processing chamber as a load. The impedance matching device has, for example, a variable capacitance element connected between a high-frequency power supply and a load, and performs impedance matching by adjusting a capacitance value of the variable capacitance element.
Disclosure of Invention
Problems to be solved by the invention
The present disclosure provides a technique capable of self-diagnosing an abnormality of each component constituting an impedance matching device.
Means for solving the problems
An impedance matching device according to an aspect of the present disclosure includes: a variable capacitance element connected between a high-frequency power source and a load; a first detector that detects an index value for determining impedance matching between the high-frequency power supply and the load and a first state value representing a state of a high frequency input from the high-frequency power supply; a second detector that detects a second state value indicating a state of a high frequency output to the load; an adjustment section that adjusts the capacitance value of the variable capacitance element step by step so that the index value detected by the first detector falls within a target range indicating completion of the impedance matching; and a diagnosis unit configured to diagnose an abnormality in the variable capacitive element, the first detector, or the second detector based on the capacitance value adjusted by the adjustment unit, the first state value detected by the first detector, and the second state value detected by the second detector.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present disclosure, it is possible to perform self-diagnosis of an abnormality in each member constituting the impedance matching device.
Drawings
Fig. 1 is a schematic cross-sectional view showing the configuration of a plasma processing apparatus according to a first embodiment.
Fig. 2 is a diagram showing an example of the configuration of the impedance matching device according to the first embodiment.
Fig. 3 is a flowchart illustrating an example of the processing operation of the impedance matching apparatus according to the first embodiment.
Fig. 4 is a diagram illustrating an example of the configuration of the impedance matching device according to the second embodiment.
Fig. 5 is a flowchart illustrating an example of the processing operation of the impedance matching apparatus according to the second embodiment.
Fig. 6 is a diagram showing an example of the configuration of the impedance matching device according to the third embodiment.
Fig. 7 is a flowchart illustrating an example of the processing operation of the impedance matching apparatus according to the third embodiment.
Description of the reference numerals
110: an impedance matching device; 124. 125: a variable capacitor; 130. 131: an input detector; 140. 141: an output detector; 161. 164: an adjustment part; 162. 163 and 165: a diagnosis unit.
Detailed Description
Hereinafter, various embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals.
Conventionally, a plasma processing apparatus has been known which performs a plasma process on an object to be processed such as a wafer by using plasma. Such a plasma processing apparatus has a stage for holding a target object, which also functions as an electrode, in a processing chamber that can form a vacuum space. The plasma processing apparatus applies a predetermined high frequency supplied from a high frequency power source to the mounting table to perform a plasma process on the object to be processed mounted on the mounting table. An impedance matching device for performing impedance matching between the high-frequency power source and the processing chamber is disposed between the high-frequency power source and the processing chamber as a load. The impedance matching device has, for example, a variable capacitance element connected between a high-frequency power supply and a load, and performs impedance matching by adjusting a capacitance value of the variable capacitance element.
However, in the impedance matching apparatus, self-diagnosis of abnormality of each component such as the variable capacitance element is not considered. Therefore, it is desirable to perform self-diagnosis of abnormality of each component constituting the impedance matching apparatus.
[ first embodiment ]
(Structure of plasma processing apparatus according to the precondition
Fig. 1 is a diagram showing a plasma processing apparatus 1 according to the precondition technique. The plasma processing apparatus 1 shown in fig. 1 includes a chamber (processing container) 12 and a microwave output device 16. The plasma processing apparatus 1 is configured as a microwave plasma processing apparatus that excites a gas with microwaves. The plasma processing apparatus 1 includes a mounting table 14, an antenna 18, and a dielectric window 20.
The chamber 12 provides a processing space S therein. The chamber 12 has a side wall 12a and a bottom 12 b. The side wall 12a is formed in a substantially cylindrical shape. The center axis of the side wall 12a substantially coincides with an axis Z extending in the vertical direction. The bottom 12b is provided on the lower end side of the side wall 12 a. The bottom portion 12b is provided with an exhaust hole 12h for exhausting air. In addition, the upper end portion of the side wall 12a is open.
A dielectric window 20 is provided above the upper end of the sidewall 12 a. The dielectric window 20 has a lower surface 20a opposite the processing space S. The dielectric window 20 closes the opening of the upper end portion of the side wall 12 a. An O-ring 19 is provided between the dielectric window 20 and the upper end of the side wall 12 a. The sealing of the chamber 12 is made more reliable by the O-ring 19.
The stage 14 is accommodated in the processing space S. The mounting table 14 is disposed to face the dielectric window 20 in the vertical direction. Further, the stage 14 is provided so as to sandwich the processing space S between the dielectric window 20 and the stage 14. The mounting table 14 is configured to support a wafer W as a target object placed on the mounting table 14.
The stage 14 includes a base 14a and an electrostatic chuck 14 c. The susceptor 14a has a substantially disk shape and is formed of a conductive material such as aluminum. The central axis of the base 14a is substantially coincident with the axis Z. The base 14a is supported by the cylindrical support portion 48. The cylindrical support portion 48 is formed of an insulating material and extends vertically upward from the bottom portion 12 b. The outer periphery of the cylindrical support portion 48 is provided with a conductive cylindrical support portion 50. The cylindrical support portion 50 extends vertically upward from the bottom 12b of the chamber 12 along the outer periphery of the cylindrical support portion 48. An annular exhaust passage 51 is formed between the cylindrical support portion 50 and the side wall 12 a.
A baffle plate 52 is provided on the upper portion of the exhaust passage 51. The baffle 52 has an annular shape. The baffle plate 52 is formed with a plurality of through holes penetrating the baffle plate 52 in the plate thickness direction. The exhaust hole 12h is provided below the baffle plate 52. The exhaust device 56 is connected to the exhaust hole 12h via the exhaust pipe 54. The exhaust unit 56 has a vacuum pump such as an Automatic pressure control valve (APC) and a turbo molecular pump. The processing space S can be depressurized to a desired degree of vacuum by the evacuation device 56.
The base 14a also serves as a high-frequency electrode. A high frequency power source 58 for rf (radio frequency) bias is electrically connected to the base 14a through a power supply rod 62 and a matching unit 60. The high-frequency power supply 58 outputs a fixed frequency suitable for controlling the energy of the ions attracted to the wafer W, for example, a high frequency of 13.65MHz (hereinafter, referred to as "high frequency for bias" as appropriate), at a set power. The matching unit 60 is an impedance matching device for impedance matching between the high-frequency power supply 58 and a load, mainly an electrode, plasma, chamber 12, or the like.
The upper surface of the base 14a is provided with an electrostatic chuck 14 c. The electrostatic chuck 14c holds the wafer W by electrostatic attraction force. The electrostatic chuck 14c includes an electrode 14d, an insulating film 14e, and an insulating film 14f, and has a substantially disk shape. The central axis of the electrostatic chuck 14c is substantially coincident with the axis Z. The electrode 14d of the electrostatic chuck 14c is formed of a conductive film, and is provided between the insulating film 14e and the insulating film 14 f. The dc power supply 64 is electrically connected to the electrode 14d via a switch 66 and a covered wire 68. The electrostatic chuck 14c can hold the wafer W by suction by coulomb force generated by the dc voltage applied from the dc power supply 64. In addition, a focus ring 14b is provided on the base 14 a. The focus ring 14b is disposed so as to surround the wafer W and the electrostatic chuck 14 c.
The base 14a is provided with a refrigerant chamber 14g therein. The refrigerant chamber 14g is formed to extend around the axis Z, for example. The refrigerant from the cooling unit is supplied to the refrigerant chamber 14g via the pipe 70. The refrigerant supplied to the refrigerant chamber 14g returns to the cooling unit through the pipe 72. The temperature of the electrostatic chuck 14c and thus the wafer W is controlled by controlling the temperature of the refrigerant by the cooling unit.
Further, a gas supply line 74 is formed in the mounting table 14. The gas supply line 74 is provided for supplying a heat transfer gas, for example, He gas, between the upper surface of the electrostatic chuck 14c and the back surface of the wafer W.
The microwave output device 16 generates microwaves having a power corresponding to the set power. The microwave output device 16 outputs, for example, a Single-frequency, i.e., Single-Peak (SP) microwave for exciting the process gas supplied into the chamber 12. The microwave output device 16 is configured to variably adjust the frequency and power of the microwave. In one example, the microwave output device 16 can adjust the power of the microwave in a range of 0W to 5000W, and can adjust the frequency of the microwave in a range of 2400MHz to 2500 MHz.
The plasma processing apparatus 1 further includes a waveguide 21, a tuner 26, a mode converter 27, and a coaxial waveguide 28. The waveguide 21 and the coaxial waveguide 28 are waveguides for guiding the microwaves generated by the microwave output device 16 to an antenna 18, which will be described later, of the chamber 12. An output portion of the microwave output device 16 is connected to one end of the waveguide 21. The other end of the waveguide 21 is connected to a mode converter 27. The waveguide 21 is, for example, a rectangular waveguide. The waveguide 21 is provided with a tuner 26. The tuner 26 has movable short circuit plates S1 to S4. The movable short-circuiting plates S1 to S4 are each configured so that the amount of projection thereof with respect to the internal space of the waveguide 21 can be adjusted. The tuner 26 adjusts the protruding position of each of the movable short circuit plates S1 to S4 with respect to a predetermined position as a reference, thereby matching the impedance of the microwave output device 16 with the impedance of the load (e.g., the chamber 12).
The mode converter 27 converts the mode of the microwave from the waveguide 21 and supplies the mode-converted microwave to the coaxial waveguide 28. The coaxial waveguide 28 includes an outer conductor 28a and an inner conductor 28 b. The outer conductor 28a has a substantially cylindrical shape, and its central axis substantially coincides with the axis Z. The inner conductor 28b has a substantially cylindrical shape and extends inside the outer conductor 28 a. The center axis of the inner conductor 28b substantially coincides with the axis Z. The coaxial waveguide 28 transmits the microwaves from the mode converter 27 to the antenna 18.
The antenna 18 is disposed on a surface 20b of the dielectric window 20 on the side opposite the lower surface 20 a. The antenna 18 includes a slot plate 30, a dielectric plate 32, and a cooling housing 34.
The slit plate 30 is disposed on the surface 20b of the dielectric window 20. The slit plate 30 is formed of a metal having conductivity, and has a substantially disk shape. The central axis of the slit plate 30 is substantially coincident with the axis Z. The slit plate 30 has a plurality of slit holes 30 a. In one example, the plurality of slit holes 30a constitute a plurality of slit pairs. Each of the plurality of slit pairs includes two slit holes 30a of a substantially long hole shape extending in directions intersecting each other. The plurality of slot pairs are arranged along one or more concentric circles about the axis Z. A through hole 30d through which a duct 36 described later can pass is formed in the center of the slit plate 30.
A dielectric plate 32 is disposed over the slit plate 30. The dielectric plate 32 is formed of a dielectric material such as quartz and has a substantially disk shape. The central axis of the dielectric plate 32 substantially coincides with the axis Z. A cooling housing 34 is disposed over the dielectric plate 32. The dielectric plate 32 is disposed between the cooling case 34 and the slit plate 30.
The surface of the cooling housing 34 has electrical conductivity. A flow passage 34a is formed inside the cooling casing 34. The refrigerant is supplied to the flow path 34 a. The lower end of the outer conductor 28a is electrically connected to the upper surface of the cooling case 34. The lower end of the inner conductor 28b is electrically connected to the slot plate 30 through a hole formed in the center portion of the cooling case 34 and the dielectric plate 32.
The microwave from coaxial waveguide 28 propagates through dielectric plate 32 and is supplied to dielectric window 20 from a plurality of slot holes 30a of slot plate 30. The microwaves supplied to the dielectric window 20 are introduced into the processing space S.
The conduit 36 passes through the inner bore of the inner conductor 28b of the coaxial waveguide 28. As described above, the central portion of the slit plate 30 is formed with the through hole 30d through which the conduit 36 can pass. Conduit 36 extends through the inner bore of inner conductor 28b and is connected to gas supply 38.
The gas supply system 38 supplies a process gas for processing the wafer W to the conduit 36. The gas supply system 38 may include a gas source 38a, a valve 38b, and a flow controller 38 c. The gas source 38a is a source of process gas. The valve 38b switches between supply and stop of the process gas from the gas source 38 a. The flow controller 38c is, for example, a mass flow controller for adjusting the flow of the process gas from the gas source 38 a.
The plasma processing apparatus 1 may further include an injector 41. The injector 41 supplies the gas from the conduit 36 to the through hole 20h formed in the dielectric window 20. The gas supplied to the through-holes 20h of the dielectric window 20 is supplied to the processing space S. Then, the process gas is excited by the microwaves introduced into the process space S from the dielectric window 20. Thereby, plasma is generated in the processing space S, and the wafer W is processed by active species such as ions and radicals from the plasma.
The plasma processing apparatus 1 also has a controller 100. The controller 100 collectively controls the respective portions of the plasma processing apparatus 1. The controller 100 may include a processor such as a CPU, a user interface, and a storage unit.
The processor executes the program and the process stored in the storage unit to collectively control the microwave output device 16, the mounting table 14, the gas supply system 38, the exhaust device 56, and the like. The processor stores various measurement values and the like in the storage unit.
The user interface includes a keyboard and a touch panel for inputting commands and the like by a process administrator to manage the plasma processing apparatus 1, a display for visually displaying the operating state and the like of the plasma processing apparatus 1, and the like.
The storage unit stores a control program (software) for realizing various processes executed by the plasma processing apparatus 1 under the control of the processor, a process recipe including process condition data, and the like. The processor calls and executes various control programs from the storage unit as necessary in accordance with instructions from the user interface and the like. Under the control of such a processor, a desired process is executed in the plasma processing apparatus 1. The storage unit may store the monitoring results corresponding to the executed process recipe (process conditions) in association with each other. The monitoring result includes the above-described tuner position, a measurement value (described later) measured by the microwave output device 16, and the like.
(Structure of impedance matching device)
Next, the configuration of the impedance matching device 110 according to the first embodiment will be described. Fig. 2 is a diagram illustrating an example of the configuration of the impedance matching device 110 according to the first embodiment. The configuration of the impedance matching device 110 shown in fig. 2 can be applied to the matching unit 60 included in the plasma processing apparatus 1 of the precondition technique shown in fig. 1, for example. The impedance matching device 110 shown in fig. 2 has an input terminal 110a connected to a high-frequency power source and an output terminal 110b connected to a load. The high-frequency power source is, for example, the high-frequency power source 58 shown in fig. 1, and the load is, for example, the chamber 12 shown in fig. 1. The input terminal 110a is a terminal to which a high frequency is input from a high frequency power supply, and the output terminal 110b is a terminal to which a high frequency is output to a load. Hereinafter, a high frequency input from the high frequency power supply to the input terminal 110a is referred to as an "input high frequency", and a high frequency output from the output terminal 110b to the load is referred to as an "output high frequency".
The impedance matching device 110 includes an impedance matching unit 120 located between the input terminal 110a and the output terminal 110b, an input detector 130, an output detector 140, a storage unit 150, and a control unit 160. The memory unit 150 and the control unit 160 may be provided outside the impedance matching device 110.
The impedance matching unit 120 is connected to the input terminal 110a via a wiring 110c, and is connected to the output terminal 110b via a wiring 110 d. The impedance matching unit 120 includes a coil 121, a coil 122, and a coil 123 connected in series to the wiring 110c and the wiring 110 d. In addition, the impedance matching section 120 has a variable capacitor 124, a variable capacitor 125, and a capacitor 126 connected at a position between the high-frequency power source and the load (that is, between the input terminal 110a and the output terminal 110 b). The variable capacitor 124 is connected in parallel with the variable capacitor 125 at a position between the input terminal 110a and the output terminal 110b, and the capacitance value thereof is variable. The capacitance values of the variable capacitors 124 and 125 are adjusted by an adjusting unit 161 of the control unit 160, which will be described later. The capacitor 126 is connected in parallel at a position between the input terminal 110a and the output terminal 110b, and its capacitance value is fixed. The number of variable capacitors connected between the high-frequency power supply and the load is not limited to 2, and may be 1, or 3 or more. Each of the variable capacitors 124 and 125 is an example of a variable capacitance element, and a coil may be used instead of a capacitor. The impedance matching section 120 may have various configurations such as a pi-type configuration and an inverted L-type configuration.
The input detector 130 is disposed on the wiring 110c, and detects an "index value" for determining impedance matching between the high-frequency power supply and the load and a "first state value" indicating a state of a high frequency (i.e., an input high frequency) input from the high-frequency power supply to the input terminal 110 a. Specifically, the input detector 130 detects a phase difference between a voltage and a current of an input high frequency as an index value, and detects a power value of the input high frequency as a first state value. The input detector 130 is an example of a first detector. In addition, as the index value, not only the phase difference between the voltage and the current of the input high frequency, but also the input forward power value and the input reflected power value can be used.
The output detector 140 is disposed on the wiring 110d, and detects a "second state value" indicating a state of a high frequency (that is, an output high frequency) output from the output terminal 110b to the load. Specifically, the output detector 140 detects the power value of the output high frequency as the second state value. The output detector 140 is an example of the second detector.
The storage unit 150 is an arbitrary storage device such as a hard disk, an optical disk, and a semiconductor memory element. The control Unit 160 is a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit).
The storage unit 150 stores therein programs and various data for executing various processes executed by the impedance matching apparatus 110 under the control of the control unit 160. For example, the storage unit 150 stores the loss information 151.
The loss information 151 is information indicating a relationship between the loss of the entire impedance matching unit 120 and the capacitance values of the variable capacitors 124 and 125. The loss information 151 is, for example, information of a table that correlates the loss with the capacitance value of the variable capacitor 124, 125. The loss information 151 may be information of a formula for calculating loss from the capacitance values of the variable capacitors 124 and 125.
The control unit 160 functions as various processing units by reading and executing programs stored in the storage unit 150. For example, the control unit 160 has an adjustment unit 161 and a diagnosis unit 162.
The adjusting section 161 adjusts the capacitance values of the variable capacitors 124, 125 step by step so that the phase difference detected by the input detector 130 falls within a target range indicating completion of impedance matching. Specifically, the adjusting unit 161 repeatedly adjusts the capacitance values of the variable capacitors 124 and 125 by an adjustment amount corresponding to the phase difference until the phase difference detected by the input detector 130 falls within the target range. When the phase difference detected by the input detector 130 falls within the target range, the adjustment unit 161 determines that the impedance matching is completed, and ends the adjustment of the capacitance values of the variable capacitors 124 and 125. When the input forward power value and the input reflected power value fall within the target ranges, adjustment unit 161 may determine that the impedance matching is completed.
The diagnosis unit 162 diagnoses an abnormality of the variable capacitors 124 and 125, the input detector 130, or the output detector 140 based on the capacitance value adjusted by the adjustment unit 161, the power value detected by the input detector 130, and the power value detected by the output detector 140. Hereinafter, the variable capacitors 124 and 125, the input detector 130, and the output detector 140 are appropriately described as " variable capacitors 124 and 125, and the like".
Here, an example of the abnormality diagnosis performed by the diagnosis unit 162 will be described.First, the diagnostic unit 162 calculates a theoretical value of the power value of the output high frequency based on the capacitance value adjusted by the adjustment unit 161 and the power value detected by the input detector 130. For example, the diagnostic unit 162 acquires the loss corresponding to the capacitance value adjusted by the adjustment unit 161 using the loss information 151. Then, the diagnostic unit 162 calculates a theoretical value of the power value of the output high frequency by subtracting the acquired loss from the power value detected by the input detector 130. Theoretical value P of output high-frequency power value calculated by diagnostic unit 162outRepresented by the following formula (1).
Pout＝Pin-Ploss(C1、C2)…(1)
In the formula (1), PinIs the value of the power of the input high frequency, Ploss(C1, C2) is a loss corresponding to the capacitance values C1, C2 of the variable capacitors 124, 125.
Then, when the difference between the theoretical value of the calculated power value and the power value detected by the output detector 140 is equal to or greater than a predetermined threshold value, the diagnostic unit 162 determines that an abnormality has occurred in the variable capacitors 124 and 125.
Thus, the impedance matching device 110 can determine the occurrence of an abnormality using the deviation between the actually detected output high-frequency power value and the theoretical value of the output high-frequency power value, and can self-diagnose the abnormality of each component constituting the impedance matching device 110.
(processing operation of impedance matching device)
Next, a processing operation of the impedance matching device 110 according to the first embodiment will be described. Fig. 3 is a flowchart illustrating an example of the processing operation of the impedance matching apparatus 110 according to the first embodiment. In the case where the impedance matching apparatus 110 is applied to the matching unit 60 included in the plasma processing apparatus 1 of the precondition technique shown in fig. 1, for example, in the plasma processing apparatus 1, the processing operation shown in fig. 3 is executed at the timing of starting the plasma processing with respect to the wafer W.
As shown in fig. 3, the adjusting unit 161 acquires the phase difference between the voltage and the current of the input high frequency and the power value of the input high frequency detected by the input detector 130 (step S11).
The adjusting section 161 determines whether or not the acquired phase difference falls within a target range indicating completion of impedance matching (step S12). When the acquired phase difference does not fall within the target range (no in step S12), the adjusting section 161 adjusts the capacitance values of the variable capacitors 124, 125 by an adjustment amount corresponding to the phase difference (step S13), and the process returns to step S11. Thus, the capacitance values of the variable capacitors 124 and 125 are repeatedly adjusted until the phase difference falls within the target range.
On the other hand, when the acquired phase difference falls within the target range (yes in step S12), the adjusting unit 161 finishes adjusting the capacitance values of the variable capacitors 124 and 125, and advances the process to step S14.
The diagnostic unit 162 acquires the loss corresponding to the capacitance values of the variable capacitors 124 and 125 adjusted by the adjusting unit 161 using the loss information 151 (step S14). Then, diagnostic unit 162 calculates a theoretical value of the power value of the output high frequency by subtracting the acquired loss from the power value of the input high frequency acquired in step S11 (step S15).
The diagnostic unit 162 acquires the output high frequency power value detected by the output detector 140 (step S16).
Diagnostic unit 162 determines whether or not the difference between the theoretical value of the power value of the output high frequency calculated in step S15 and the power value of the output high frequency acquired in step S16 is equal to or greater than a predetermined threshold (step S17). When the difference between the calculated theoretical value of the power value of the output high frequency and the acquired power value of the output high frequency is smaller than the predetermined threshold value (no in step S17), diagnostic unit 162 determines that no abnormality has occurred in variable capacitors 124, 125, etc. (step S18). On the other hand, when the difference between the calculated theoretical value of the power value of the output high frequency and the acquired power value of the output high frequency is equal to or greater than the predetermined threshold value (yes in step S17), diagnostic unit 162 determines that an abnormality has occurred in variable capacitors 124, 125, etc. (step S19).
After diagnosing the abnormality of the variable capacitors 124 and 125, the diagnostic unit 162 may output a diagnostic result indicating whether or not the abnormality of the variable capacitors 124 and 125 has occurred to a predetermined output unit. In addition, the diagnosis unit 162 may alarm when it is determined that an abnormality has occurred in the variable capacitors 124, 125, or the like. The alarm may be given by any method as long as it can report an abnormality to an administrator or the like of the impedance matching apparatus 110. When determining that an abnormality has occurred in the variable capacitors 124 and 125, the diagnostic unit 162 may stop the high-frequency power supply and cut off the input high frequency.
As described above, the impedance matching device 110 according to the first embodiment includes the variable capacitors 124 and 125, the input detector 130, the output detector 140, the adjustment unit 161, and the diagnosis unit 162. The variable capacitors 124, 125 are connected between a high frequency power source (e.g., the high frequency power source 58) and a load (e.g., the chamber 12, etc.). The input detector 130 detects an index value for determining impedance matching between the high frequency power source and the load and a first state value representing a state of a high frequency input from the high frequency power source. The output detector 140 detects a second state value indicating the state of the high frequency output to the load. The adjusting section 161 adjusts the capacitance values of the variable capacitors 124, 125 step by step so that the detected index value falls within a target range indicating the completion of impedance matching. The diagnosis unit 162 diagnoses an abnormality in the variable capacitors 124 and 125, the input detector 130, or the output detector 140 based on the adjusted capacitance value, the detected first state value, and the detected second state value. Thus, the impedance matching apparatus 110 can self-diagnose an abnormality of each component (for example, the variable capacitors 124 and 125, the input detector 130, or the output detector 140) constituting the impedance matching apparatus 110.
In the impedance matching device 110 according to the first embodiment, the input detector 130 detects a phase difference between a voltage and a current of a high frequency input from the high frequency power supply as an index value, and detects a power value of the high frequency input from the high frequency power supply as a first state value. The output detector 140 detects a power value of a high frequency output to the load as a second state value. The adjusting section 161 adjusts the capacitance values of the variable capacitors 124, 125 step by step so that the phase difference detected by the input detector 130 falls within a target range. The diagnostic unit 162 calculates a theoretical value of the power value of the high frequency to be output to the load based on the adjusted capacitance value and the power value detected by the input detector 130. When the difference between the theoretical value of the calculated power value and the power value detected by the output detector 140 is equal to or greater than a predetermined threshold value, the diagnostic unit 162 determines that an abnormality has occurred. Thus, the impedance matching device 110 can accurately determine the occurrence of an abnormality using the deviation between the actually detected power value of the output high frequency and the theoretical value of the power value of the output high frequency.
[ second embodiment ]
Next, a second embodiment will be explained.
(Structure of impedance matching device)
Fig. 4 is a diagram illustrating an example of the configuration of the impedance matching device 110 according to the second embodiment. Since the impedance matching device 110 according to the second embodiment has substantially the same configuration as the impedance matching device 110 according to the first embodiment shown in fig. 2, the same reference numerals are given to the same portions, the description thereof is omitted, and the description thereof will be mainly given to different portions. The configuration of the impedance matching device 110 shown in fig. 4 can be applied to the matching unit 60 included in the plasma processing apparatus 1 of the precondition technique shown in fig. 1, for example.
The impedance matching device 110 shown in fig. 4 has an output detector 141 and a diagnostic section 163 instead of the output detector 140 and the diagnostic section 162 shown in fig. 2.
The output detector 141 detects V of high frequency (i.e., output high frequency) output from the output terminal 110b to the loadppThe value and the impedance value on the load side are taken as second state values. VppThe value is an amplitude value of the high-frequency voltage.
The diagnosis unit 163 detects the value of the capacitance, the power value detected by the input detector 130, and the value of V detected by the output detector 141 based on the capacitance adjusted by the adjustment unit 161ppThe values and the impedance value on the load side are used to diagnose the abnormality of the variable capacitors 124, 125, etc.
Here, an example of the abnormality diagnosis performed by the diagnosis unit 163 will be described. First, examineThe disconnection unit 163 calculates V based on the capacitance value adjusted by the adjustment unit 161, the power value detected by the input detector 130, and the load-side impedance value detected by the output detector 141ppTheoretical value of the value. For example, the diagnostic unit 163 acquires the loss corresponding to the capacitance value adjusted by the adjustment unit 161 using the loss information 151. Then, the diagnostic unit 163 calculates a theoretical value of the power value of the output high frequency by subtracting the acquired loss from the power value detected by the input detector 130. Theoretical value P of output high-frequency power value calculated by diagnostic unit 163outRepresented by the above formula (1). Then, the diagnosis unit 163 calculates V as shown in the following equation (2) based on the theoretical value of the calculated output high-frequency power value and the load-side impedance value detected by the output detector 141ppTheoretical value of the value.
[ EQUATION 1 ]
In the formula (2), VppIs VppTheoretical value of value, PoutIs a theoretical value of the power value of the output high frequency, R is a real part of the impedance value on the load side, and X is an imaginary part of the impedance value on the load side.
Then, at the calculated VppTheoretical value of value and V detected by output detector 141ppWhen the difference in value is equal to or greater than the predetermined threshold value, the diagnostic unit 163 determines that an abnormality has occurred in the variable capacitors 124, 125, and the like.
Thus, the impedance matching device 110 can use the actually detected VppValue and VppThe occurrence of an abnormality is determined by the deviation of the theoretical value of the value, and the abnormality of each component constituting the impedance matching device 110 can be self-diagnosed.
(processing operation of impedance matching device)
Next, a processing operation of the impedance matching device 110 according to the second embodiment will be described. Fig. 5 is a flowchart illustrating an example of the processing operation of the impedance matching apparatus 110 according to the second embodiment. In the case where the impedance matching apparatus 110 is applied to the matching unit 60 included in the plasma processing apparatus 1 of the precondition technique shown in fig. 1, for example, in the plasma processing apparatus 1, the processing operation shown in fig. 5 is executed at the timing of starting the plasma processing with respect to the wafer W.
As shown in fig. 5, the adjusting unit 161 acquires the phase difference between the voltage and the current of the input high frequency and the power value of the input high frequency detected by the input detector 130 (step S21).
The adjusting section 161 determines whether or not the acquired phase difference falls within a target range indicating completion of impedance matching (step S22). When the acquired phase difference does not fall within the target range (no in step S22), the adjusting section 161 adjusts the capacitance values of the variable capacitors 124, 125 by an adjustment amount corresponding to the phase difference (step S23), and the process returns to step S21. Thus, the capacitance values of the variable capacitors 124 and 125 are repeatedly adjusted until the phase difference falls within the target range.
On the other hand, when the acquired phase difference falls within the target range (yes in step S22), the adjusting unit 161 finishes adjusting the capacitance values of the variable capacitors 124 and 125, and advances the process to step S24.
The diagnostic unit 163 acquires the loss corresponding to the capacitance values of the variable capacitors 124 and 125 adjusted by the adjustment unit 161, using the loss information 151 (step S24). Then, the diagnostic unit 163 calculates a theoretical value of the power value of the output high frequency by subtracting the acquired loss from the power value of the input high frequency acquired in step S21 (step S25).
The diagnosis unit 163 acquires the load-side impedance value detected by the output detector 141 (step S26). Then, the diagnosing unit 163 calculates V based on the theoretical value of the power value of the output high frequency calculated in step S25 and the impedance value on the load side acquired in step S26ppTheoretical value of value (step S27).
The diagnosis unit 163 acquires V detected by the output detector 141ppThe value (step S28).
The diagnosis unit 163 determines V calculated in step S27ppTheoretical value of valueWith V acquired in step S28ppWhether or not the difference in value is equal to or greater than a predetermined threshold value (step S29). At calculated VppTheoretical value of value and V obtainedppIf the difference in values is smaller than the predetermined threshold value (no in step S29), the diagnostic unit 163 determines that no abnormality has occurred in the variable capacitors 124, 125, etc. (step S30). On the other hand, at the calculated VppTheoretical value of value and V obtainedppIf the difference in values is equal to or greater than the predetermined threshold value (yes at step S29), the diagnostic unit 163 determines that an abnormality has occurred in the variable capacitors 124, 125, etc. (step S31).
After diagnosing the abnormality of the variable capacitors 124 and 125, the diagnostic unit 163 may output a diagnostic result indicating whether or not the abnormality of the variable capacitors 124 and 125 has occurred to a predetermined output unit. The diagnosis unit 163 may alarm when it is determined that an abnormality has occurred in the variable capacitors 124 and 125. The alarm may be given by any method as long as it can report an abnormality to an administrator or the like of the impedance matching apparatus 110. When determining that an abnormality has occurred in the variable capacitors 124 and 125, the diagnostic unit 163 may stop the high-frequency power supply and cut off the input high frequency.
As described above, in the impedance matching device 110 according to the second embodiment, the input detector 130 detects the phase difference between the voltage and the current of the high frequency input from the high frequency power supply as the index value, and detects the power value of the high frequency input from the high frequency power supply as the first state value. The output detector 141 detects the high frequency V output to the loadppThe value and the impedance value on the load side are taken as the second state values. The adjusting section 161 adjusts the capacitance values of the variable capacitors 124, 125 step by step so that the phase difference detected by the input detector 130 falls within a target range. The diagnosis unit 163 calculates V based on the adjusted capacitance value, the power value detected by the input detector 130, and the load-side impedance value detected by the output detector 141ppTheoretical value of the value. At calculated VppTheoretical value of value and V detected by output detector 141ppWhen the difference in value is equal to or greater than the predetermined threshold, the diagnosis unit 163 determines that a discrepancy has occurredOften times. Thus, the impedance matching device 110 can use the actually detected VppValue and VppThe occurrence of an abnormality is accurately determined by the deviation of the theoretical value of the value.
[ third embodiment ]
Next, a third embodiment will be explained.
(Structure of impedance matching device)
Fig. 6 is a diagram showing an example of the configuration of an impedance matching device 110 according to the third embodiment. The impedance matching device 110 according to the third embodiment has substantially the same configuration as the impedance matching device 110 according to the first embodiment shown in fig. 2, and therefore, the same portions are denoted by the same reference numerals, and description thereof is omitted, and description thereof will be mainly given to different portions. The configuration of the impedance matching device 110 shown in fig. 6 can be applied to the matching unit 60 included in the plasma processing apparatus 1 of the precondition technique shown in fig. 1, for example.
The impedance matching device 110 shown in fig. 6 includes an input detector 131, an adjusting unit 164, and a diagnostic unit 165 instead of the input detector 130, the adjusting unit 161, and the diagnostic unit 162 shown in fig. 2. In the impedance matching device 110 shown in fig. 6, the output detector 140 and the loss information 151 shown in fig. 2 are omitted.
The input detector 131 is disposed on the wiring 110c, and detects an "index value" for determining impedance matching between the high-frequency power supply and the load. Specifically, the input detector 131 detects a phase difference between the voltage and the current of the input high frequency as an index value. The input detector 131 is an example of a detector.
The adjusting section 164 adjusts the capacitance values of the variable capacitors 124, 125 step by step so that the phase difference detected by the input detector 131 falls within a target range indicating completion of impedance matching. Specifically, the adjusting unit 164 repeatedly adjusts the capacitance values of the variable capacitors 124 and 125 by an adjustment amount corresponding to the phase difference until the phase difference detected by the input detector 131 falls within the target range. When the phase difference detected by the input detector 131 falls within the target range, the adjustment unit 164 determines that the impedance matching is completed, and ends the adjustment of the capacitance values of the variable capacitors 124 and 125.
The diagnostic unit 165 monitors the number of times the capacitance values of the variable capacitors 124 and 125 are adjusted, that is, the number of times the capacitance values are adjusted, and diagnoses an abnormality in the variable capacitors 124 and 125 or the input detector 131 based on the number of times the capacitance values are adjusted and the phase difference detected by the input detector 131. Hereinafter, the variable capacitors 124 and 125 or the input detector 131 are appropriately described as " variable capacitors 124 and 125, etc. Specifically, when the number of times of capacitance value adjustment reaches a predetermined number of times and the phase difference detected by the input detector 131 does not fall within the target range indicating completion of impedance matching, the diagnostic unit 165 determines that an abnormality has occurred in the variable capacitors 124 and 125.
Thus, in the impedance matching apparatus 110, the occurrence of an abnormality can be determined using the number of times the capacitance values of the variable capacitors 124 and 125 are repeatedly adjusted (that is, the number of times the capacitance values are adjusted), and the abnormality of each component constituting the impedance matching apparatus 110 can be self-diagnosed.
(processing operation of impedance matching device)
Next, a processing operation of the impedance matching device 110 according to the third embodiment will be described. Fig. 7 is a flowchart illustrating an example of the processing operation of the impedance matching apparatus 110 according to the third embodiment. In the case where the impedance matching apparatus 110 is applied to the matching unit 60 included in the plasma processing apparatus 1 of the precondition technique shown in fig. 1, for example, in the plasma processing apparatus 1, the processing operation shown in fig. 7 is executed at the timing of starting the plasma processing with respect to the wafer W.
As shown in fig. 7, a variable N for counting the number of times the capacitance values of the variable capacitors 124, 125 are adjusted (i.e., the number of times the capacitance values are adjusted) is initialized to 0 (step S41). The adjusting unit 164 obtains the phase difference between the input high-frequency voltage and the input high-frequency current detected by the input detector 131 (step S42).
The adjustment section 164 determines whether or not the acquired phase difference falls within a target range indicating completion of impedance matching (step S43). When the acquired phase difference falls within the target range (yes in step S43), adjustment unit 164 ends the adjustment of the capacitance values of variable capacitors 124 and 125.
On the other hand, when the acquired phase difference does not fall within the target range (no in step S43), the adjusting unit 164 adjusts the capacitance values of the variable capacitors 124 and 125 by an adjustment amount corresponding to the phase difference (step S44) and increments the number of times N the capacitance value is adjusted by 1 (step S45).
The diagnosis unit 165 determines whether the capacitance value adjustment count N has reached a predetermined count Nmax(step S46). The number of times N of capacitance adjustment does not reach the predetermined number of times NmaxIn the case of (no in step S46), the diagnostic unit 165 returns the process to step S42 and continues to adjust the capacitance values of the variable capacitors 124 and 125 by the adjustment unit 164. Thus, the capacitance values of the variable capacitors 124 and 125 are repeatedly adjusted until the phase difference falls within the target range.
On the other hand, when the capacitance value adjustment number N reaches the predetermined number NmaxIn the case of (yes in step S46), the diagnostic unit 165 acquires the phase difference between the input high-frequency voltage and the input current detected by the input detector 131 (step S47).
The diagnostic section 165 determines whether or not the acquired phase difference falls within a target range indicating completion of impedance matching (step S48). When the acquired phase difference falls within the target range (yes in step S48), the diagnostic unit 165 determines that no abnormality has occurred in the variable capacitors 124, 125, etc. (step S49). On the other hand, if the acquired phase difference does not fall within the target range (step S48: no), the diagnostic unit 165 determines that an abnormality has occurred in the variable capacitors 124, 125, etc. (step S50).
After diagnosing the abnormality of the variable capacitors 124 and 125, the diagnostic unit 165 may output a diagnostic result indicating whether or not the abnormality of the variable capacitors 124 and 125 has occurred to a predetermined output unit. In addition, the diagnosis unit 165 may alarm when it is determined that an abnormality has occurred in the variable capacitors 124 and 125. The alarm may be given by any method as long as it can report an abnormality to an administrator or the like of the impedance matching apparatus 110. When determining that an abnormality has occurred in the variable capacitors 124 and 125, the diagnostic unit 165 may stop the high-frequency power supply and cut off the input high frequency.
As described above, the impedance matching device 110 according to the third embodiment includes the variable capacitors 124 and 125, the input detector 131, the adjustment unit 164, and the diagnosis unit 165. The variable capacitors 124, 125 are connected between a high frequency power source (e.g., the high frequency power source 58) and a load (e.g., the chamber 12, etc.). The input detector 131 detects an index value for determining impedance matching between the high-frequency power supply and the load. The adjustment section 164 adjusts the capacitance values of the variable capacitors 124, 125 step by step so that the detected index value falls within a target range indicating the completion of impedance matching. The diagnostic unit 165 monitors the number of times the capacitance values of the variable capacitors 124 and 125 are adjusted, that is, the number of times the capacitance values are adjusted, and diagnoses an abnormality in the variable capacitors 124 and 125 or the input detector 131 based on the number of times the capacitance values are adjusted and the detected index value. Thus, the impedance matching apparatus 110 can self-diagnose an abnormality of each component (for example, the variable capacitors 124 and 125 or the input detector 131) constituting the impedance matching apparatus 110.
In the impedance matching device 110 according to the third embodiment, the input detector 131 detects a phase difference between a high-frequency voltage and a high-frequency current input from a high-frequency power supply as an index value. The adjusting section 164 adjusts the capacitance values of the variable capacitors 124, 125 step by step so that the phase difference detected by the input detector 131 falls within a target range. When the number of times of capacitance value adjustment reaches a predetermined number of times and the phase difference detected by the input detector 131 does not fall within the target range, the diagnostic unit 165 determines that an abnormality has occurred. Thus, the impedance matching device 110 can determine the occurrence of an abnormality with high accuracy using the number of times the capacitance values of the variable capacitors 124 and 125 are repeatedly adjusted (that is, the number of times the capacitance values are adjusted).
The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The above embodiments may be omitted, replaced or modified in various ways without departing from the spirit and scope of the appended claims.
For example, in the above embodiments, the case where the configuration of the impedance matching device 110 is applied to the matching unit included in the microwave plasma processing apparatus has been described as an example, but the impedance matching device 110 may be applied to the matching unit of another plasma processing apparatus. Examples of other Plasma processing apparatuses include Plasma processing apparatuses using Capacitive Coupled Plasma (CCP), Inductive Coupled Plasma (ICP), Electron Cyclotron Resonance Plasma (ECR), and Helicon Wave Plasma (HWP).
