JPH0992491A - Device and method for plasma processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of dust, breaking and contamination of a base surface, and dielectric breakdown of electric elements by detecting the generation of the abnormal discharge of a plasma, and reducing the frequency of the occurrence of the discharge. SOLUTION: A base 2 to be processed is placed within a plasma processing vessel 1, the inside of the vessel is evacuated, and gas is introduced from a gas inlet 4. A predetermined high frequency is produced from a high frequency source 5 and amplified by a high-frequency power amplifier 7 via a high-frequency switch 6. Next, it is divided by a directional coupler 8 into a propagating wave 8a to a fundamental susceptor 3 and a reflected wave 8b, and a matching unit 9 is controlled by a matching unit control device 10 so that the reflected-wave power is at a minimum while the propagating-wave power is at a maximum. If an abnormal discharge occurs, a wave detector 1 detects it, a voltage comparator 12 compares it with a reference voltage source 13, and a signal is produced from a trigger generator 14. Further, the high-frequency power is controlled by a gate circuit 15 according to information from the matching unit control device 10. Thus by suppressing the generation of the abnormal discharge the generation of dust, breaking and contamination of the base surface, and dielectric breakdown of electric elements are prevented.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus, and detects abnormal discharge occurring in a plasma processing container during processing, reduces abnormal shape of a substrate to be processed, and electrostatic damage, and at the same time, abnormal discharge. The present invention relates to a plasma processing apparatus capable of preventing the plasma processing container from being damaged by the above and suppressing the progress of consumption.

2. Description of the Related Art As semiconductor devices such as DRAM (Dynamic RAM) logic LSIs and microprocessors become higher in density and higher in performance, the importance of fine processing technology and high-purity film formation technology for elements, wirings, etc. Is increasing. For the above-mentioned fine processing and high-purity film formation, plasma is generated from a halogen-based gas to perform etching, or plasma is generated from an inorganic material gas or an organic material gas to form C
The film is formed by VD (chemical vapor deposition method). A plasma processing apparatus having parallel plate electrodes will be described with reference to FIG. A substrate susceptor 103 is provided inside the plasma processing container 101, and a substrate 102 to be processed is placed thereon. The plasma processing container 101 is evacuated by using a turbo molecular pump, an oil diffusion pump, or the like (not shown). Then, a reactive gas is introduced into the gas introduction port 104 to maintain the inside of the plasma processing container 101 at a constant pressure. Next, the high frequency generated by the high frequency source 105 is amplified by the high frequency amplifier 106 to the electric power required to generate plasma, and the amplified high frequency is directional coupler 107 and matching device 108.
And is applied to the substrate susceptor 103. When the plasma is generated, the matching device controller 109 controls the substrate susceptor 10
The capacitance of the variable capacitor in the matching unit 108 is changed so as to match the high-frequency impedance applied to the signal No. 3 and the like. Generally, the inside of the plasma processing container 101 is provided to prevent metal contamination of the substrate 102 to be processed.
Aluminum whose surface is anodized is used. The alumite layer is usually about 100 by anodic oxidation method.
It is formed on the order of nm. In a CVD method or an etching process in which a reaction product having a relatively low vapor pressure is generated, a deposited film is easily formed on the alumite layer, and when the deposited film is formed as the etching process is repeated, the surface of the deposited film is charged up. . If a large number of minute arc discharges occur near the surface of the deposited film for some reason, a large amount of the deposited film will peel off, causing dust. Due to the generation of dust, there is a problem in that elements and wirings in the substrate 102 to be processed are short-circuited or disconnected. Further, in order to prevent the above problems, it is necessary to perform maintenance such as cleaning the plasma processing container 101 before the deposited film starts to come off to a certain thickness or more. However, it was difficult to know exactly when to perform this maintenance. On the other hand, when a metal wiring such as aluminum is formed by etching, Cl ₂ or BCl ₃ gas is introduced into the plasma processing container 101 to generate plasma, but Cl ₂ or BCl ₃ gas is highly reactive, so the plasma processing container The alumite layer on the inner surface of 101 is gradually etched. When the alumite layer is etched and disappears, aluminum on the inner wall is exposed, and when abnormal discharge such as arc discharge occurs in this state, aluminum on the inner wall or metal impurities such as iron and magnesium other than aluminum contaminate the substrate to be treated. There was a problem. In addition, the plasma processing container 1 until aluminum is exposed
There is a problem that it is difficult to know the service life of 01 and it is difficult to accurately grasp the timing of performing maintenance. Furthermore, if an abnormal discharge occurs near the substrate to be processed, the substrate itself may be damaged in shape, or the element may be electrostatically destroyed or deteriorated, resulting in a significant decrease in the production yield of the substrate to be processed such as a semiconductor device. It was

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and suppresses the frequency of occurrence of abnormal discharge, sudden dust generation due to abnormal discharge, damage to the surface of a substrate to be treated, and substrate. It is an object of the present invention to provide a plasma processing apparatus capable of reducing the above-mentioned contamination and the occurrence of dielectric breakdown of electric elements of a substrate.

In order to solve the above problems, a first aspect of the present invention is to provide a means for generating high frequency power, a plasma processing vessel for power supply, a means for introducing gas into the plasma processing vessel, and a plasma processing vessel. An electrode for introducing a high frequency into the electrode, a means for detecting high frequency power reflected from the electrode, an impedance of the high frequency power applied to the electrode, and an amplitude of the high frequency power reflected from the electrode in a state where the impedance of the plasma is matched. A plasma processing apparatus comprising: means for controlling high-frequency power applied to an electrode depending only on fluctuations. The first aspect of the present invention
In more concrete terms, the means for controlling the high frequency power includes means for recognizing that the impedance of the high frequency power applied to the electrode and the impedance of the plasma are matched, and the amplitude of the high frequency power reflected from the electrode. And a means for recognizing that the impedance is in a matched state, and a means for controlling the high frequency power applied to the electrode based on information from the means for detecting the variation in amplitude. Consists of. In the first aspect of the present invention,
The control of the high frequency power by the means for controlling the high frequency power is particularly effective for abnormal discharge that occurs in the vicinity of the substrate to be processed. Further, in order to solve the above-mentioned problems, a second aspect of the present invention comprises means for generating plasma in the plasma processing container, means for introducing gas into the plasma processing container, and means for introducing microwave into the plasma processing container. Provided is a plasma processing apparatus comprising: a means for detecting a microwave reflected in plasma; and a means for controlling an output of a means for generating a plasma according to a variation in the amplitude of the detected microwave. To do. In order to solve the above-mentioned problems, a third aspect of the present invention is to provide a plasma processing container, means for generating plasma in the plasma processing container, means for introducing gas into the plasma processing container, and microwave for the plasma processing container. And means for detecting microwaves that have passed through the plasma, and means for controlling the output of the means for generating plasma according to the fluctuations in the amplitude or phase of the detected microwaves. A plasma processing apparatus is provided. In the second to third aspects of the present invention, the means for controlling the high-frequency power is controlled according to the fluctuation of the amplitude of the microwave in a specific frequency band. This is preferable in that it enables measurement according to the frequency band and enables accurate detection of abnormal discharge. Furthermore, in order to solve the above-mentioned problems, a fourth aspect of the present invention is to provide a plasma processing container, means for generating plasma in the plasma processing container, means for introducing gas into the plasma processing container, and the inside of the plasma processing container. A plasma processing apparatus comprising: a unit for detecting the intensity of emitted light; and a unit for controlling an output of a unit for generating plasma and a high frequency in accordance with a variation in the detected emission intensity. Further, in the first to fourth plasma processing apparatuses of the present invention, it is provided with means for measuring the number of times of fluctuations in the amplitude of the high frequency power reflected from the electrodes, fluctuations in the amplitude or phase of the microwave, and fluctuations in the emission intensity. It is preferable to grasp the progress of damage and consumption of the plasma processing container. In the fourth aspect of the present invention, it is preferable that the means for controlling the high frequency power is controlled in accordance with the variation of the emission intensity at a specific wavelength for more accurate detection of abnormal discharge.
A fifth aspect of the present invention is to introduce a process gas into the plasma processing container, to introduce high-frequency power from an electrode into the plasma processing container to generate plasma, and to apply high-frequency power to the electrode. The method is characterized in that the step of controlling the high frequency power applied to the electrode is performed only in accordance with the fluctuation of the amplitude of the high frequency power reflected from the electrode in a state where the impedance and the impedance of the plasma are matched. According to the first and fifth aspects of the present invention, the occurrence of abnormal discharge is detected early in response to the fluctuation of the amplitude of the high frequency power reflected from the electrode, and applied to the electrode before the abnormal discharge can grow. The abnormal discharge can be reduced by the means for controlling the high frequency power. Further, the impedance is matched in order to control the high frequency power applied to the electrode only in accordance with the fluctuation of the amplitude of the high frequency power reflected from the electrode in the state where the impedance of the high frequency power is matched with the means for generating the high frequency power. Since the power control is not performed depending on the fluctuation of the amplitude of the high frequency power reflected from the electrode in the absence state, there is no problem that the high frequency power is unnecessarily cut off and reduced to lower the throughput. Further, since the reflection from the electrode is detected, it is also possible to detect a minute fluctuation of the plasma in the vicinity of the electrode which causes damage to the gas to be processed. According to the second and sixth aspects of the present invention, the microwave is introduced into the plasma processing container, and the microwave reflected by the plasma or the microwave transmitted through the plasma is detected. When an abnormal discharge occurs in the plasma container, the plasma density (electron density) locally increases, and the plasma frequency proportional to the plasma density increases. If microwaves are introduced here, the microwave transmittance of the plasma is reduced, the amplitude is changed (the microwaves reflected by the plasma are increased), and the amplitude of the transmitted microwaves is delayed.
By controlling the output of the means for generating plasma in response to the fluctuation of the amplitude or the fluctuation of the phase, the occurrence of the abnormal discharge is detected at the initial stage, and the abnormal discharge grows.
It can be reduced before damaging the gas to be treated. Moreover, it is possible to detect abnormal discharge throughout the entire plasma processing container regardless of the vicinity of the electrodes. Further, according to the fourth and seventh aspects of the present invention, the emission intensity in the plasma processing container at the time of occurrence of abnormal discharge is detected, and the output of the means for generating plasma is controlled according to the variation, so that the abnormality is generated. It can be detected and reduced at the initial stage of discharge occurrence. Further, regardless of the vicinity of the electrodes, it is possible to detect the abnormal discharge throughout the inside of the plasma processing container.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a plasma etching apparatus according to a first embodiment of the present invention. A substrate susceptor 3 on which a substrate 2 to be processed is placed is installed in the plasma processing container 1. First, the plasma processing container 1
Is evacuated by a turbo molecular pump or an oil diffusion pump (not shown), and a gas for generating active species such as ions or radicals necessary for processing is introduced from a gas inlet 4 connected to the plasma processing container 1. After introducing the gas, the inside of the plasma processing container 1 is maintained at a constant pressure. A high frequency of 13.56 MHz is generated by the high frequency source 5, and the high frequency is amplified by the high frequency power amplifier 7 through the high frequency switch 6 to a power required for generating plasma. The amplified high frequency is separated by the directional coupler 8 into traveling waves 8b and 8a to the substrate susceptor 3. The matching wave control device 10 controls the variable reactance elements such as the variable capacitors of the matching box 9 so that the reflected wave power becomes minimum and the traveling wave power becomes maximum. That is, the matching box 9 is operated so as to match the impedance of the high frequency applied to the substrate susceptor with the impedance of the generated plasma so that the maximum power is supplied to the substrate susceptor 3. The high frequency switch 6 is normally ON, that is, it allows high frequencies to pass through. Further, when a high frequency is generated and plasma is generated in the plasma processing container 1, the matching device 9 and the matching device controller 10 perform the impedance matching operation described above for several seconds. The high-frequency switch 6 is controlled by the gate circuit 15 so that the high-frequency switch 6 is kept in the ON state during the period when the matching operation is performed after the high-frequency is generated. When an abnormal discharge such as an arc discharge occurs in the plasma processing container 1 for some reason during the processing after the plasma is generated, the reflected wave output 8a of the directional coupler 8 is displayed. As shown in FIG. 2, a pulsed output a is generated. The generated reflected output pulse is envelope-detected by the detector 11. The waveform detected by the detector 11 becomes a waveform as shown in FIG. 3a '. However, in FIGS. 2 and 3, when the high-frequency switch 6 is always turned on regardless of the presence or absence of arc discharge, that is, the high-frequency switch 6 of the present embodiment is always turned on and the operation of reducing abnormal discharge is not performed. Is a voltage waveform when.
The pulse signal detected by the detector 11 is the reference DC voltage Vth generated by the reference voltage source 13 by the voltage comparator 12.
(Indicated by a broken line in FIG. 3). When the voltage exceeds the reference voltage above, it is considered that an abnormal discharge has occurred,
A trigger signal for operating the pulse generator 14 is generated. The high frequency cutoff pulse generated by the pulse generator 14 by the trigger signal is shown in FIG. A pulse is generated whose time is approximately equal to or slightly longer than the duration of the abnormal discharge shown in FIG. 2a. It is assumed that the high frequency cutoff pulse is not transmitted to the high frequency switch 6 by the gate circuit 15 during the impedance matching operation. This is because the reflected wave voltage may exceed the reference DC voltage Vth of the reference voltage source 13 during the matching operation of the impedance of the high frequency power source and the plasma impedance.
This is because there may be an oscillation phenomenon in which the high frequency is turned off (cut off) and the high frequency is turned on again after the cutoff pulse period. This is an adverse effect caused by the fact that the present embodiment determines the occurrence of abnormal discharge and detects the oscillation phenomenon that could not be measured conventionally because the high-frequency control up to the high-frequency control by the switch 6 is accelerated. it is conceivable that. Therefore, in the present embodiment, in order to prevent the erroneous operation, it is assumed that the high frequency power is not controlled by the gate circuit 15 when the information indicating that the impedance is not matched is obtained from the matching device controller 10. There is. The pulse number indicator 16 can be used to measure the number of abnormal discharges to know the degree of growth and wear of the deposited film of the plasma processing container 1, and to be used as a guide for maintenance and replacement of the plasma processing container 1. it can. When dry etching is performed by using this plasma processing apparatus, the reflected wave pulse waveform is extinguished in the course of occurrence of abnormal discharge as shown in FIG. The wavy line is the one when the abnormal discharge reducing operation according to the present embodiment is not performed. Moreover, the frequency of occurrence of abnormal discharge is about 60 to 80% by the pulse number display 16.
A decreasing effect was seen. The progress of consumption of the plasma processing container 1 was suppressed and the life of the plasma processing container 1 could be extended. The cutoff pulse period may be set to a period equal to or longer than the duration of the abnormal discharge, and until the time when the plasma is extinguished and does not affect the matching operation, that is, the electron temperature in the plasma is set to the decay time or less. Specifically, the cutoff pulse time is 10
Microseconds to 10 milliseconds are good, and preferably 50 microseconds to 500 microseconds. In the present embodiment, the abnormal discharge is detected by comparing the output pulse of the detector with the DC reference voltage of the reference voltage source, but this is abnormal due to pulse differentiation of the output waveform of the detector by a differentiating circuit etc. Discharge may be detected. Next, a plasma processing apparatus according to a second embodiment of the present invention will be described with reference to FIG. The gas supply system and the exhaust system are the same as those in the first embodiment, and detailed description thereof will be omitted. The same components as those in the first embodiment will be designated by the same reference numerals and the description of the reference numerals will be omitted. Similar to the first embodiment, after introducing gas, the inside of the plasma processing container 1 is maintained at a constant pressure,
Subsequently, the high frequency generated by the high frequency source 5 passes through the high frequency switch 6 and is amplified by the high frequency power amplifier 7 to the power required for generating plasma. On the other hand, the microwave of 35 GHz generated by the microwave source 21 is radiated by the transmission horn antenna 23 through the porous microwave directional coupler 22. The radiated microwave is made incident into the plasma processing container 1 through the first quartz window 24. Electron density n of plasma normally used in a plasma processing apparatus
_e is 10 ⁹ to 10 ¹³ / cm ³ . At this time (proportional to n _e ^0.5) plasma frequency w _p is about 10~100GHzn
o In the microwave range. In a uniform plasma 2 in which abnormal discharge does not occur, microwaves having a higher frequency than the plasma frequency are incident and propagate in the plasma without attenuation. When an abnormal discharge occurs in the plasma processing container, the electron density ne increases locally, and the plasma frequency also increases accordingly. When the plasma frequency exceeds the frequency of the incident microwave, it cannot propagate in the plasma and is attenuated. This phenomenon is called cutoff. At the same time, microwave reflection occurs. Even in this case, the microwave reflected from the plasma due to the abnormal discharge is incident on the transmission horn antenna 23. The incident reflected wave is extracted by the microwave directional coupler 22 and detected by the first microwave detector 27. FIG. 7 shows the detection output voltage of the first microwave detector 27 when abnormal discharge occurs. When the abnormal discharge occurred, the pulse waveform accompanying the abnormal discharge was obtained as in the first embodiment. on the other hand,
The microwave that has passed through the plasma is the plasma processing container 1
Is guided to the reception horn antenna 26 from the second quartz window of the. The passing microwave obtained by the reception horn antenna 26 is detected by the second microwave detector 28. FIG. 8 shows the detection output voltage of the second microwave detector 28 when abnormal discharge occurs. When the abnormal discharge occurred, a pulse waveform that decreased with the abnormal discharge was obtained contrary to FIG. 7. Here, when plasma is generated and processing is performed, when the output pulse of the first microwave detector 27 becomes equal to or higher than a certain DC reference voltage Vth generated by the reference voltage source 12, the voltage comparator 13 Sends a trigger signal to the pulse generator 14. The changeover switch 29 changes over the method of detecting abnormal discharge due to reflection or passage of microwaves. At the same time, the logic inverter 30 is used to switch the output positive / negative logic of the voltage comparator 13. This is because when the second microwave detector 28 detects an abnormal discharge, it is necessary to send a trigger to the pulse generator 14 at the DC reference voltage Vth or less. In any of the above methods for detecting abnormal discharge due to reflection and transmission of microwaves, it is possible to reduce abnormal discharge by shutting off the high frequency for a certain period of time by the high frequency switch 6 as in the first embodiment. In this embodiment, the abnormal discharge is detected by detecting the amplitude of the reflected or passed microwave, but this is detected by detecting the delay of the phase change of the reflected or passed microwave. You may. Subsequently, a plasma processing apparatus according to a third embodiment will be described with reference to the drawings. FIG. 9 is a schematic configuration diagram thereof. The gas supply system and the exhaust system are the same as those in the first embodiment. Similar to the first and second embodiments, after introducing gas, the inside of the plasma processing container 1 is maintained at a constant pressure. Subsequently, the high frequency generated by the high frequency source 5 passes through the high frequency switch 6 and is amplified by the high frequency power amplifier 7 to the power required for generating plasma. Here, when plasma is generated and processing is performed, if an abnormal discharge occurs, the emission intensity increases during the generation of the abnormal discharge. Therefore, after detecting the emission intensity of the plasma collected from the first quartz window 24 with the emission intensity detector 31, the pulse sorter 32 extracts only the intensity change of the emission due to the abnormal discharge of about 50 microseconds to 500 macroseconds. Send a trigger signal to the output. This is to avoid malfunction due to fluctuations in light emission intensity due to factors other than abnormal discharge during plasma processing. The trigger signal obtained by the pulse classifier 31 is made into a pulse of a fixed time by the pulse generator 14 as in the above-described first and second embodiments,
It was possible to reduce abnormal discharge by shutting off the high frequency for a certain time by the high frequency switch 6. In the present embodiment, the abnormal discharge is detected by detecting the change in the emission intensity incident on the emission intensity detector 31, but the emission intensity detector 31 is provided with a spectrometer or the like to identify the abnormal discharge. It is also possible to detect the wavelengths of the ions and active species and detect the abnormal discharge more accurately. Although each embodiment of the present invention reduces the occurrence of abnormal discharge by cutting off high frequencies, this may reduce the output of high frequencies. Further, although the embodiments of the present invention have described the method of generating a plasma by applying a high frequency to the substrate susceptor, this is not limited to means for generating a plasma by using inductive coupling, plasma electron cyclotron resonance, helicon wave, or the like. The abnormal discharge may be prevented by blocking or reducing the high frequency and microwave outputs of the means for generating plasma when the abnormal discharge occurs. Further, in the above plasma processing apparatus, when a high frequency bias is applied to the substrate susceptor, the high frequency bias may be blocked or reduced.

EFFECTS OF THE INVENTION The occurrence of abnormal discharge in the plasma processing container is detected, the frequency of occurrence of abnormal discharge is suppressed, and sudden dust generation due to abnormal discharge, damage to the surface of the substrate to be treated, contamination of the substrate, and electrical discharge of the substrate. It is possible to reduce the occurrence of dielectric breakdown of the element.

[Brief description of drawings]

FIG. 1 is a schematic structural diagram of a plasma processing apparatus that is a first embodiment of the present invention.

FIG. 2 is a diagram showing a reflected wave output pulse of the directional coupler 8 when an abnormal discharge occurs in the first embodiment.

FIG. 3 is a diagram showing an output pulse of a detector 11 when an abnormal discharge occurs in the first embodiment.

FIG. 4 is a diagram showing an output pulse of a pulse generator when an abnormal discharge occurs in the first embodiment.

FIG. 5 is a schematic structural diagram of a plasma processing apparatus according to a second embodiment.

FIG. 6 is a diagram showing a reflected wave when an abnormal discharge is reduced by operating a high frequency switch of the plasma processing apparatus in the first embodiment.

FIG. 7 is a diagram showing an output pulse of a first microwave detector 27 when an abnormal discharge occurs in the second embodiment.

FIG. 8 is a diagram showing an output pulse of a second microwave detector when an abnormal discharge occurs in the second embodiment.

FIG. 9 is a schematic structural diagram of a plasma processing apparatus according to a third embodiment.

FIG. 10 is a diagram showing an output pulse of a light emission intensity detector 31 when an abnormal discharge occurs in the third embodiment.

FIG. 11 is a schematic configuration diagram showing a conventional plasma processing apparatus.

[Explanation of symbols]

 1, 101 ... Plasma container 2, 102 ... Substrate to be processed 3, 103 ... Substrate susceptor 4, 104 ... Gas inlet 5, 105 ... High frequency source 6 ... High frequency switch 7, 106 ... High frequency power amplifier 8, 207 ... Directional coupling Matching device 9, 108 ... Matching device 10 ... Matching device control device 11 ... Detector 12 ... Voltage comparator 13 ... Reference voltage source 14, 109 ... Pulse generator 15 ... Gate circuit 16 ... Pulse number display 21 ... Microwave source 22 ... Microwave directional coupler 23 ... Transmission horn antenna 24 ... First quartz window 25 ... Reception horn antenna 26 ... Second quartz window 27 ... First microwave amplitude detector 28 ... Second microwave amplitude detector 29 ... Changeover switch 30 ... Logic inverter 31 ... Emission intensity detector 32 ... Pulse sorter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/3065 H01L 21/302 B

Claims (7)

[Claims] 1. A means for generating high frequency power, a plasma processing container, a means for introducing gas into the plasma processing container, an electrode for introducing high frequency power into the plasma processing container, and high frequency power reflected from this electrode is detected. And a means for controlling the high-frequency power applied to the electrode only in accordance with the fluctuation of the amplitude of the high-frequency power reflected from the electrode in a state where the impedance of the high-frequency power applied to the electrode and the impedance of the plasma are matched. A plasma processing apparatus comprising: 2. Means for generating plasma in the plasma processing container, plasma processing container, means for introducing gas into the plasma processing container, means for introducing microwave into the plasma processing container, and reflection to plasma A plasma processing apparatus comprising: a means for detecting a microwave; and a means for controlling an output of a means for generating plasma according to a variation in the detected amplitude of the microwave. 3. Means for generating plasma in the plasma processing container, plasma processing container, means for introducing gas into the plasma processing container, means for introducing microwave into the plasma processing container, and microwave transmitting plasma. A plasma processing apparatus comprising: a means for detecting a wave; and a means for controlling an output of a means for generating plasma according to a variation in amplitude or a phase of the detected microwave. 4. Means for generating plasma in the plasma processing container, plasma processing container, means for introducing gas into the plasma processing container, means for detecting intensity of light emission in the plasma processing container, and the plasma A plasma processing apparatus comprising: a means for controlling the output of the generating means according to the variation of the emission intensity detected. 5. A step of introducing a process gas into the plasma processing container, a step of introducing high frequency power from an electrode into the plasma processing container to generate plasma, and an impedance of the high frequency power applied to the electrode and an impedance of the plasma. And a step of controlling the high-frequency power applied to the electrode only in accordance with the variation of the amplitude of the high-frequency power reflected from the electrode in a state where the and are matched. 6. A step of introducing a process gas into the plasma processing container, a step of generating plasma using a means for generating plasma in the plasma processing container, and a step of introducing microwaves into the plasma processing container. Detecting the microwave reflected in the plasma or the microwave transmitted through the plasma, and generating the plasma according to the variation in the amplitude of the reflected microwave or the variation in the amplitude or the phase of the transmitted microwave And a step of controlling the output of the means. 7. A step of introducing a process gas into the plasma processing container, a step of generating plasma using a means for generating plasma in the plasma processing container, and detecting the intensity of light emission in the plasma processing container. A plasma processing method comprising performing a step and a step of controlling an output of a means for generating the plasma according to a variation in the detected emission intensity.