JP2003017296A - Plasma density information measuring method and device therefor, as well as plasma density information measuring probe, its recording medium and plasma treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma density information measuring method and its device that grasp the plasma density information easily and carry out plasma treatment easily, and a plasma density information measuring probe, its recording media and a plasma treatment device. SOLUTION: The probe control part 8 comprises a frequency outputting part 17, a DBM(double balanced mixer) 18, and a BPF(band pass filter) 19, and it is a heterodyne type in which the frequency outputting part 17 outputs by adding/subtracting a prescribed amount of frequency to/from the output frequency outputted by the measuring power source 6, and the DBM 18 subtracts the frequency outputted by the frequency outputting part 17 from the reflection frequency of the power reflected by the plasma load PM and the BPF 19 passes only the frequency which matches the prescribed frequency through it. By this construction, entering of the noise can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to plasma density information based on reflection or absorption of plasma density information measuring power supplied from a plasma density information measuring power source for measuring plasma density information into a plasma. Plasma density information measuring method and apparatus for measuring
The present invention also relates to a probe for measuring plasma density information, a recording medium for measuring plasma density information, and a plasma processing apparatus.

[0002]

2. Description of the Related Art Plasma CVD (chemical vapor deposition), plasma etching and the like are known as techniques to which plasma is applied. In such plasma application technology, a plasma processing chamber (for example, a chamber) for performing plasma processing.
Since the plasma in the inside changes with time, it is very important to adequately understand the information about the plasma density that shows the characteristics of the generated plasma, that is, the plasma density information, in order to perform appropriate processing. There are quantities related to electron density, that is, absorption frequency, plasma surface wave resonance frequency, etc., as useful physical quantities relating to plasma density information. By measuring these frequencies and the like, plasma density information can be sufficiently grasped and plasma processing can be performed.

As a method of measuring plasma density information,
The present inventors have previously proposed the invention of Japanese Patent Laid-Open No. 2000-100598. In the present invention, as shown in FIG. 15, a plasma density information measuring probe 101 for measuring plasma density information (hereinafter referred to as "measurement probe 1" as appropriate).
01 ”is abbreviated as“ 01 ”), which is a chamber 1 which is a plasma processing chamber.
02, and from the power supply 103 for measuring plasma density information for measuring plasma density information (hereinafter, abbreviated as “power supply 103 for measurement” as appropriate) to the power for measuring plasma density information (hereinafter, “power for measurement” as appropriate). (Abbreviated as “electric power”) is supplied to the plasma PM in the chamber 102 to perform the measurement. The measurement probe 101 includes an antenna 104 that radiates electric power and a coaxial cable 1 that transmits electric power for measurement.
05 and a tube 106 made of a dielectric material whose tip is closed. The antenna 104 and the coaxial cable 105 are connected and inserted in the tube 106 made of a dielectric material.

Measurement power is radiated from the measurement power source 103 to the antenna 104 via the coaxial cable 105 and supplied to the plasma PM in the chamber 102. The measurement power supplied to the plasma PM in the chamber 102 is absorbed by the plasma load due to the plasma density or is reflected and returns via the coaxial cable 105. That is, the measurement power supplied to the plasma PM excites the surface wave of the plasma on the surface of the dielectric tube 106 of the measurement probe 101, thereby absorbing or reflecting the plasma load. Plasma density information is measured based on the reflection or absorption of the measuring power.

More specifically, the measuring power supply 103 is a frequency sweep type, and outputs the measuring power automatically while sweeping it at a frequency in a certain frequency band (for example, 100 kHz to 2.5 GHz). When the measurement power is absorbed or reflected, the reflected power of the power is transmitted in the direction opposite to the direction in which it is supplied to the plasma PM in the chamber 102, and the measurement probe 1
01 and the power source 103 for measurement are detected by the directional coupler 107 and sent to the output device 108 for outputting to a monitor or the like. The frequency of the measurement power output from the measurement power supply 6 is also sequentially sent to the output device 108.

The output device 108 obtains a change in reflectance of the measuring power with respect to frequency based on the frequency of the measuring power and the detected reflection amount of the measuring power. That is, at the same frequency, [detection reflection amount of measurement power] / [total output amount of measurement power] is calculated to obtain the reflectance of measurement power,
The frequency to be swept and the reflectance of the measurement power are associated and plotted. Then, based on the obtained results, the absorption frequency at which strong measurement power absorption occurs due to the electron density is obtained. Since the above-mentioned absorption frequency has a certain correlation with plasma density information such as electron density, the plasma density information can be easily obtained by obtaining the absorption frequency.

[0007]

However, the measuring probe (plasma density information measuring probe) having such a structure has the following problems. That is,
Since noise is mixed in the plasma density information, it takes time to set up the power supply for measuring plasma density information (power supply for measurement) for measuring the plasma density information, and it takes time to measure the plasma density information. There is a problem that it becomes difficult for an operator (operator) who measures the measurement probe to grasp the plasma density information and perform the plasma processing.

First, the fact that noise is mixed in the plasma density information will be described. After being reflected or absorbed by the plasma PM load, plasma PM is added to the power of the reflected component.
Inside noise is also mixed and detected by the directional coupler 107. Therefore, since the data such as the reflectance sent from the directional coupler 107 to the output device 108 contains noise, the plasma density information cannot be accurately measured. As a result, it becomes difficult for the operator to grasp the plasma density information and perform the plasma processing.

Next, it will be described that it takes time to set up the power source for measurement. An oscillating closed circuit controlled by a phase difference signal is usually used as the above-mentioned frequency sweep type power supply for measurement. Such an oscillation closed circuit is
(Phase Looked Loop) ”is commonly called. Figure 1
As shown in FIG.
109 is a phase comparator 110 and a low pass filter (L
PF (Low Pass Filter) 111 (hereinafter referred to as “LP
F ”) and a voltage controlled oscillator (VCO (Voltag
e Controlled Oscillator)) 112 (hereinafter referred to as “V
CO ”) and the programmable divider 113.
It has and. The phase comparator 110 compares the phases of the reference (reference) frequency f _ref with the respective output frequencies f ₀ to be swept, and the phase difference signal obtained by the comparison is compared with the LPF1.
11 is provided with a function. The LPF 111 has a function of passing only the low-frequency component of the phase difference signal, converting it into a voltage, and giving the voltage to the VCO 112. The VCO 112 has a function of outputting a frequency according to the magnitude of the voltage from the LPF 111 and sweeping the output frequency as each output frequency f ₀ . The programmable divider 113 divides the output frequency f ₀ output from the VCO 112 when the division ratio is set to N, and the divided frequency (f ₀ / N) is calculated by the phase comparator 1
It plays the function to give to 10. The above-described oscillation closed circuit (PLL) allows the phase comparators 110 to LPF111.
~ VCO 112 ~ Programmable Divider 113 ~ Each time the phase comparator 110 is cycled (looped), each output frequency f ₀ is sequentially swept to f _ref , 2f _ref , 3f _ref , ....

However, in the case of such an oscillation closed circuit, since the phase difference signal for driving the LPF 111 in the oscillation closed circuit is a voltage, the response speed of the LPF 111 is slow, and as a result, it takes time to set up the power source for measurement. Will end up. Further, it takes time to sweep the frequency, and during that time, the plasma density information changes with time, which may cause a difference between the obtained plasma density information measurement result and the actual plasma density information. As a result, it becomes difficult for the operator to grasp the plasma density information and perform the plasma processing.

Next, it will be described that it takes time to measure the plasma density information. The above-mentioned points at which strong absorption of the measuring power occurs (hereinafter referred to as “absorption points”) are observed at a plurality of points. Therefore, the absorption frequency, which is the frequency at that absorption point, is also measured by the number of absorption points. Q factor (quality factor)
The absorption frequency at the maximum absorption point is called the "zeroth absorption frequency" or the "basic absorption frequency". Then, the absorption frequencies are defined as primary, secondary, ... In descending order of absorption. The highest-order absorption frequency, that is, the absorption frequency at the absorption point with the smallest absorption is called the "plasma surface wave resonance frequency". The plasma surface wave resonance frequency is one of useful physical quantities when deriving plasma density information such as electron density.

Actually, in order to measure the plasma density information, the absorption having a large Q value is a large absorption (loss due to reflection) and has a narrow half width, so that the absorption frequency having the largest Q value, that is, It is usual to measure the zero-order absorption frequency (fundamental absorption frequency). The fundamental absorption frequency depends on the shape of the measurement probe, such as the length of the antenna of the measurement probe and the outer diameter of the tube described above. On the other hand, the plasma surface wave resonance frequency described above does not depend on the shape of the measurement probe, and if the plasma density information is constant, the corresponding plasma surface wave resonance frequency is also constant. However, this plasma surface wave resonance frequency is difficult to observe because its absorption is small as described above. Therefore, in order to measure the plasma density information, for example, the fundamental absorption frequency is changed by changing the length of the antenna, and when the length of the antenna approaches 0 without limit, a plurality of absorption frequencies including the fundamental frequency are detected. Converge to. When the length of the antenna approaches 0, the converged absorption frequency is regarded as the plasma surface wave resonance frequency and measured, and the plasma density information is measured from the measured plasma surface wave resonance frequency. .

As described above, the basic absorption frequency is measured by changing the shape of the measuring probe, the plasma surface wave resonance frequency is specified, and the plasma density information is obtained. Therefore, it takes a lot of time to measure the plasma density information. Will end up.
Furthermore, since absorption points are observed at multiple locations,
If the difference in absorption between the basic absorption frequency and other absorption frequencies is small, and if the noise component is superimposed on the reflected power by the influence of noise, specify which absorption frequency is the basic absorption frequency. Becomes difficult. As a result, it becomes difficult for the operator to grasp the plasma density information and perform the plasma processing.

The present invention has been made in view of such circumstances, and it is possible to easily grasp the plasma density information,
Another object of the present invention is to provide a plasma density information measuring method and apparatus for easily performing plasma processing, a plasma density information measuring probe, a plasma density information measuring recording medium, and a plasma processing apparatus.

[0015]

The present invention has the following constitution in order to achieve such an object. That is, the invention according to claim 1 is a plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a) a plasma density information measuring power supply for measuring the plasma density information. The process of supplying the plasma density information measuring power to the plasma, and (b) the plasma density information measuring probe is used to measure the plasma density information based on the reflection or absorption of the plasma density information measuring power by the plasma load. In the step (a), the plasma density information measuring power is output while sweeping the frequency from the plasma density information measuring power source, and the plasma density information measuring power is supplied to the plasma for each frequency. In the process of supplying, said (b)
In the process of, the predetermined frequency is added or subtracted to or from each output frequency, which is each frequency swept from the power source for measuring plasma density information, and each frequency is obtained by the addition or subtraction. Each addition / subtraction frequency is output, and each addition / subtraction frequency is subtracted from each reflection frequency which is each frequency of the plasma density information measuring power reflected or absorbed by the plasma load. Among the frequencies obtained by the subtraction, only the frequency corresponding to the value of the predetermined frequency is passed to obtain the reflection or absorption of the plasma density information measuring power, and the process of measuring the plasma density information is performed. It is a feature.

[Operation / Effect] According to the invention described in claim 1, the plasma density information measuring power (hereinafter referred to as “power for measuring plasma density information”) , Abbreviated as "measurement power" as appropriate)
Is absorbed by the plasma load due to the plasma density or is reflected and returned via the probe for measuring plasma density information. Based on the reflection or absorption of the measuring power, the plasma density information is measured using the plasma density information measuring probe. Since the plasma density information indicates the characteristics of the plasma, the characteristics of the plasma can be grasped by measuring the plasma density information.

At this time, in the step (b), a predetermined frequency is added to or subtracted from each output frequency swept from the measurement power source (plasma density information measurement power source), and the addition or subtraction is performed. Each addition / subtraction frequency which is each frequency obtained by the subtraction is output. Then, each addition / subtraction frequency is subtracted from each reflection frequency of the measurement power (plasma density information measurement power) reflected or absorbed by the plasma load. The measurement power reflected by the plasma load also contains a noise component. Therefore, there are apparently a plurality of reflection frequencies of the measurement power, including the frequencies due to the influence of noise. At a certain output frequency, if the addition / subtraction frequency obtained by adding or subtracting a predetermined frequency to or from the output frequency is subtracted from the reflected frequency of the reflected measurement power, a plurality of noise frequencies will be included, including the effect of noise. To get the frequency of. The output frequency swept from the measurement power has the same value as the reflection frequency of the measurement power reflected when noise is not taken into consideration.
Of the plurality of frequencies obtained by the subtraction with the subtraction frequency, the absolute value of the frequency obtained by the subtraction of the net reflection frequency and the addition / subtraction frequency without considering the noise is the same value as the above-mentioned predetermined frequency. become. Similarly, for the other swept output frequencies, the absolute value of the frequency obtained by the subtraction of the net reflection frequency and the addition / subtraction frequency without considering the noise becomes the same value as the predetermined frequency.

Therefore, of the plurality of frequencies obtained by the subtraction of the reflection frequency and the addition / subtraction frequency, the absolute value of the frequency obtained by the subtraction of the net reflection frequency and the addition / subtraction frequency without considering the noise. However, only the subtracted frequency is passed and is output as the reflected component of the measurement power at that time.
As a result, the mixing of noise can be reduced and the plasma density information can be easily grasped. It should be noted that the method based on the process of (b) is as follows.
ne) method ”, and is described later.
The heterodyne method is also used for 0, 21, and claims 2, 11, and 22 including claim 1 and subordinate to those claims, respectively.

According to a second aspect of the present invention, in the plasma density information measuring method according to the first aspect, in the step (b), the output frequency is output from a plasma generation power source for generating plasma. This is a process of removing the frequency component and outputting it as the reflection or absorption of the plasma density information measuring power when the frequency of the higher harmonic wave related to the generated plasma generating power matches.

[Operation / Effect] Even if only the predetermined frequency is passed as described above, if the above-mentioned output frequency matches the frequency of the harmonic related to the power for plasma generation, even noise due to the harmonic is mixed. And output as the measurement result of the plasma density information. Therefore, according to the invention described in claim 2, even when noise due to a harmonic is mixed in when the output frequency matches the frequency of the harmonic,
Since the frequency component at the harmonic is removed and then output, noise due to the harmonic is not output as the measurement result of the plasma density information (reflection or absorption of the power for measuring the plasma density information). As a result, the plasma density information can be grasped more accurately.

Of course, when the fundamental absorption frequency and the harmonic frequency described above coincide with each other, the measurement of the fundamental absorption frequency is hindered, but the latter (harmonic frequency) usually has a very narrow spectrum width ( That is, since the Q value is high), it is unlikely to cause a problem in measuring the fundamental absorption frequency. In addition, since the plasma density information changes continuously, it is possible to determine it from the context.

According to a third aspect of the present invention, there is provided a plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a) a power source for measuring plasma density information for measuring the plasma density information. Measuring the plasma density information based on the reflection or absorption of the plasma density information measuring power by the plasma load using the process of supplying the plasma density information measuring power to the plasma from (b) the plasma density information measuring probe. In the step (a), the power for plasma density information measurement is output while sweeping the frequency from the power source for plasma density information measurement, and the power for plasma density information measurement is converted into plasma for each frequency. In the process of supplying each, the power source for measuring plasma density information is an oscillating closed circuit controlled by a phase difference signal. There are low-pass filters of the oscillation closed circuit is characterized in being driven by a current.

[Operation / Effect] According to the third aspect of the invention, the measurement power is output from the measurement power supply while sweeping the frequency, and the measurement power is supplied to the plasma for each frequency. An oscillation closed circuit controlled by a phase difference signal is used as this sweeping power supply for measurement, and the low pass filter in this oscillation closed circuit is driven by current,
The time required to set up the measurement power supply can be reduced as compared with the case of voltage driving. As a result, the plasma density information can be measured by sweeping the frequency from the power source for measurement before the plasma density information changes with time, and the plasma density information can be easily grasped.

The invention according to claim 4 is: (a) supplying the plasma density information measuring power from the plasma density information measuring power source for measuring the plasma density information to the plasma; and (b) plasma density And a step of measuring plasma density information based on reflection or absorption of the plasma density information measuring power by a plasma load, using the information measuring probe, wherein the steps (a) and (b) include:
(Ab1) Of a plurality of absorption frequencies that are frequencies caused by reflection or absorption due to a plasma load, a basic absorption frequency that is an absorption frequency at a reflectance with the largest loss of power for measuring plasma density information due to reflection, and a plasma density A storage process of storing the correlation of information in advance for each shape of the plasma density information measuring probe,
(Ab2) a fundamental frequency measuring process of supplying plasma density information measuring power from the plasma density information measuring power source to the plasma, and measuring the fundamental absorption frequency using the plasma density information measuring probe; and (ab3) (ab2) ) Is a plasma density information measurement process of measuring plasma density information based on the fundamental absorption frequency measured in the fundamental frequency measurement process and the correlation previously stored in the storage process of (ab1). It is a feature.

[Operation / Effect] According to the invention as set forth in claim 4, the correlation between the basic absorption frequency and the plasma density information is previously calculated for each shape of the probe for measuring plasma density information from the storage process of (ab1). Memorize and store the above (ab
According to the fundamental absorption frequency process of 2), the fundamental absorption frequency is measured using the plasma density information measuring probe. Then, the plasma density information is measured based on the fundamental absorption frequency measured in the process of (ab2) and the correlation stored in advance in the process of (ab1).

Therefore, since the above correlation is stored in advance according to the shape of the probe, the plasma density information can be immediately measured only by measuring the fundamental absorption frequency. As a result, the plasma density information can be easily grasped as compared with the conventional case.

According to a fifth aspect of the present invention, in the plasma density information measuring method according to the fourth aspect, the (ab1)
(AB1) measuring the basic absorption frequency for each shape of the probe for measuring the plasma density information (AB1),
(AB2) a step of measuring a plasma surface wave resonance frequency which is a constant frequency observed regardless of the shape of the probe for measuring plasma density information, and (AB3) the above (AB
1) Based on the process of (AB2), the process of obtaining the correlation of the plasma density information having a constant correlation with the fundamental absorption frequency and the plasma surface wave resonance frequency and storing the correlation. It is characterized by being.

[Operation / Effect] According to the invention described in claim 5, in the process of (ab1), the fundamental absorption frequency which depends on the shape of the probe for measuring plasma density information and the plasma surface wave resonance frequency which does not depend on it And are measured, and the above correlation is obtained and stored in advance.

According to a sixth aspect of the present invention, in the plasma density information measuring method according to the fourth aspect, the (ab1)
The memory process of (AB4) models the probe for measuring plasma density information into a concentric three-layer cylinder model in which air, a dielectric, and plasma are laminated from the center outward,
And (AB5) a longitudinal direction of the concentric three-layer cylindrical model, in which the fundamental absorption frequency is obtained for the length of the concentric three-layer cylindrical model in the longitudinal direction based on the geometrical analysis method of performing analysis using electrostatic approximation. Of the fundamental surface absorption frequency and the plasma surface wave based on the steps of (AB6) above (AB4) and (AB5) This is a process of obtaining a correlation of plasma density information having a constant correlation with the resonance frequency and storing the correlation.

[Operation / Effect] According to the invention described in claim 6, in the step (ab1), the probe for measuring plasma density information is provided with air, a dielectric,
The above correlation is obtained by obtaining a fundamental absorption frequency and a plasma surface wave resonance frequency based on a geometric analysis method in which a concentric three-layer cylinder model laminated in plasma is modeled and analysis is performed using electrostatic approximation. It is obtained in advance and stored.

According to a seventh aspect of the present invention, in the plasma density information measuring method according to the fourth aspect, the (ab1)
The memory process is based on the finite difference time domain method (AB7) in which the air, the dielectric, the plasma, and the antenna forming the plasma density information measuring probe are gridded in spatial coordinates to obtain the time change and the area change of the electromagnetic field. Then, the process of obtaining the basic absorption frequency for each shape of the probe for measuring plasma density information by obtaining the reflectance of the frequency-dependent electromagnetic field, and (AB8) the constant absorption observed regardless of the shape of the probe for measuring plasma density information. Based on the process of obtaining the plasma surface wave resonance frequency, which is the frequency, based on the finite difference time domain method, and (AB9) based on the processes of (AB7) and (AB8), the basic absorption frequency and the plasma surface wave resonance frequency are determined. On the other hand, it is a process of obtaining a correlation of plasma density information having a constant correlation and storing the correlation. It is an.

[Operation / Effect] According to the invention described in claim 7, the step (ab1) is performed by the air which constitutes the probe for measuring plasma density information,
Dielectric, plasma, antenna are made into a grid in space coordinates,
Based on the finite-difference time-domain method for obtaining the time change and the region change of the electromagnetic field, the fundamental absorption frequency and the plasma surface wave resonance frequency are obtained, and the above correlation is obtained and stored in advance.

The invention according to claim 8 is a plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a) a power source for measuring plasma density information for measuring the plasma density information. And (b) measuring the plasma density information based on the reflection or absorption of the plasma density information measuring power by the plasma load using the plasma density information measuring probe The process of doing
(C) repeating the steps (a) to (b) a plurality of times, and outputting each result of the plasma density information obtained in the step (b) over time. It is characterized by being present.

[Operation / Effect] According to the invention described in claim 8, in the process of (c), each process of (a) to (b) is repeated a plurality of times, and Each result of the plasma density information obtained in the process is output as time passes. Therefore, the plasma density information can be grasped for each time series.

According to a ninth aspect of the present invention, there is provided a plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a) a plasma density information measuring power supply for measuring the plasma density information. And (b) measuring the plasma density information based on the reflection or absorption of the plasma density information measuring power by the plasma load using the plasma density information measuring probe The process of doing
(D) A step of repeating each of the steps (a) to (b) a plurality of times to obtain each result of the plasma density information obtained in the step (b) with respect to time,
(E) a step of integrating the values of the plasma density information at each time obtained in the step (d) with respect to time and deriving the time integration of the plasma density information. Is.

[Operation / Effect] According to the invention described in claim 9, in the step (d), each of the steps (a) to (b) is repeated a plurality of times, and Each result of the plasma density information obtained in the process is obtained with respect to time, and in the process of (e), the value of the plasma density information at each time obtained in the process of (d) is integrated with respect to time, Derive the time integration of plasma density information. Therefore, the time-integrated plasma density information can be grasped.

According to a tenth aspect of the present invention, there is provided a plasma density information measuring device for measuring plasma density information indicating characteristics of plasma, which is used for measuring plasma density information while sweeping a frequency to measure the plasma density information. A power source for measuring plasma density information that supplies electric power to the plasma, a probe for measuring plasma density information that measures plasma density information based on reflection or absorption of the power for measuring plasma density information by a plasma load, and for measuring plasma density information First frequency output means for outputting each addition / subtraction frequency which is each frequency obtained by adding or subtracting a predetermined frequency to each output frequency which is each frequency swept from the power supply, and plasma Each frequency of the power for measuring the plasma density information reflected or absorbed by the load For each reflected frequency is, the sum output from each of the first frequency output means /
Second frequency output means for subtracting and outputting the subtracted frequencies, and frequency passing means for passing only the frequency that matches the value of the predetermined frequency from among the frequencies obtained by the second frequency output means. And first output means for outputting electric power at the frequency passed by the frequency passing means as reflected or absorbed electric power for measuring plasma density information.

[Operation / Effect] According to the invention described in claim 10, the plasma density information measuring power (measurement power) incident from the plasma density information measuring power source (measuring power source) is the plasma density information. Via the measuring probe, it is absorbed by the plasma load due to the plasma density or is reflected back. Based on the reflection or absorption of the measuring power, the plasma density information is measured using the plasma density information measuring probe. Since the plasma density information indicates the characteristics of the plasma, the characteristics of the plasma can be grasped by measuring the plasma density information.

At this time, the following actions and effects are achieved by additionally including the first and second frequency output means, the frequency passing means, and the first output means. That is, the first frequency output means outputs each addition / subtraction frequency obtained by adding or subtracting a predetermined frequency to or from each output frequency swept from the measurement power supply (plasma density information measurement power supply). . Then, the second frequency output means subtracts each of the above-mentioned addition / subtraction frequencies from each reflection frequency of the measurement power (power for plasma density information measurement) reflected or absorbed by the plasma load. As described in claim 1, the measurement power reflected by the plasma load also includes a noise component, and the reflection frequency of the measurement power is apparently
There are a plurality of frequencies including frequencies affected by noise. Also, the output frequency swept from the measurement power has the same value as the reflection frequency of the measurement power reflected when noise is not taken into account, so it is obtained by subtraction of the reflection frequency and the addition / subtraction frequency. Of the plurality of frequencies, the absolute value of the frequency obtained by the subtraction of the net reflection frequency and the addition / subtraction frequency that does not consider noise becomes the same value as the above-mentioned predetermined frequency.

Therefore, among the respective frequencies obtained by the second frequency output means, only the frequency obtained by subtracting the net reflection frequency and the addition / subtraction frequency without considering noise is determined by the frequency passing means. The signal is passed as if it coincides with the same value as the frequency of, and the power at the frequency at that time is output as the reflected component of the measurement power by the first output means. As a result, the mixing of noise can be reduced and the plasma density information can be easily grasped.

According to an eleventh aspect of the present invention, in the plasma density information measuring apparatus according to the tenth aspect, the first output means outputs the output frequency from a plasma generation power source for generating plasma. When there is a match with the frequency of a harmonic related to the generated power for plasma generation, it is provided with a harmonic removing means for removing the frequency component and outputting the reflected or absorbed power for measuring plasma density information. To do.

[Operation / Effect] According to the invention described in claim 11, since the first output means is provided with the harmonic wave removing means, the output frequency is from the plasma generating power supply for generating plasma. In the case where the frequency of the higher harmonic wave related to the output electric power for plasma generation matches, even if noise due to the higher harmonic wave is mixed, the frequency component in the higher harmonic wave is removed by the higher harmonic wave removing means and is output. As a result, since no harmonic noise is output from the measurement result, the plasma density information can be grasped more accurately.

According to a twelfth aspect of the present invention, there is provided a plasma density information measuring device for measuring plasma density information indicating plasma characteristics, which is used for measuring plasma density information while sweeping a frequency to measure the plasma density information. A plasma density information measuring power supply for supplying electric power to plasma, and a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the plasma density information measuring power by a plasma load, the plasma density The information measuring power supply includes a low-pass filter that passes a low-pass frequency and a current conversion unit that converts a phase-difference signal into a current for driving the low-pass filter. It is characterized in that it is a controlled oscillation closed circuit.

[Operation / Effect] According to the twelfth aspect of the present invention, the measuring power is output while sweeping the frequency from the measuring power supply, and the measuring power is supplied to the plasma for each frequency. An oscillation closed circuit controlled by a phase difference signal is used as this sweeping type power supply for measurement. This oscillating closed circuit includes a low-pass filter that passes a low-pass frequency and a current converter that converts a phase difference signal into a current for driving the low-pass filter. Therefore, the low-pass filter is driven by the current converted by the current converting means, and the time required for setting up the measurement power supply can be reduced as compared with the case of voltage driving. As a result, the plasma density information can be measured by sweeping the frequency from the power source for measurement before the plasma density information changes with time, and the plasma density information can be easily grasped.

A thirteenth aspect of the present invention is a plasma density information measuring apparatus for measuring plasma density information indicating plasma characteristics, which is used for measuring plasma density information while sweeping a frequency to measure the plasma density information. A plasma density information measuring power supply for supplying electric power to the plasma, a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the plasma density information measuring power by the plasma load, and a reflection by the plasma load or Of a plurality of absorption frequencies due to absorption, the basic absorption frequency, which is the absorption frequency at the reflectance with the largest loss of power for measuring plasma density information due to reflection, and the correlation between the plasma density information and the plasma density information. Correlation records stored in advance for each shape of the information measurement probe It is characterized in further comprising a means.

[Operation / Effect] According to the invention described in claim 13, the basic absorption frequency measured by using the plasma density information measuring probe and the shape of each plasma density information measuring probe by the correlation memory are stored. The plasma density information is measured based on the correlation between the basic absorption frequency and the plasma density information stored in advance. Since the above correlation is stored in advance in the correlation storage means according to the shape of the probe, the plasma density information can be immediately measured only by measuring the fundamental absorption frequency. As a result, the plasma density information can be easily grasped as compared with the conventional case.

According to a fourteenth aspect of the present invention, in the plasma density information measuring apparatus according to the thirteenth aspect, the correlation storing means measures the basic absorption frequency for each shape of the plasma density information measuring probe, The result obtained by measuring the plasma surface wave resonance frequency, which is a constant frequency observed regardless of the shape of the plasma density information measurement probe, is constant with respect to the fundamental absorption frequency and the plasma surface wave resonance frequency. It is characterized in that the plasma density information has a correlation.

[Operation / Effect] According to the invention described in claim 14, the correlation storage means has a basic absorption frequency dependent on the shape of the probe for measuring plasma density information, and a plasma surface wave resonance frequency independent thereof. Is measured and the above correlation is obtained and stored in advance.

According to a fifteenth aspect of the present invention, in the plasma density information measuring apparatus according to the thirteenth aspect, the correlation storing means sets the plasma density information measuring probe to air and dielectric from the center toward the outside. Based on a geometric analysis method in which a concentric three-layer cylinder model laminated on a body and plasma is modeled and analyzed by electrostatic approximation
Obtaining the fundamental absorption frequency for the length in the longitudinal direction of the layered cylinder model, and determining the frequency that converges when the length in the longitudinal direction of the concentric three-layered cylinder model approaches 0 as the plasma surface wave resonance frequency. It is characterized in that the result obtained in (1) is used as a correlation of plasma density information having a constant correlation with the fundamental absorption frequency and the plasma surface wave resonance frequency.

[Operation / Effect] According to the invention as set forth in claim 15, in the correlation storing means, the plasma density information measuring probe is laminated on the air, the dielectric and the plasma from the center to the outside. The above-mentioned correlation is obtained in advance and memorized by obtaining the fundamental absorption frequency and the plasma surface wave resonance frequency based on the geometric analysis method of modeling into a concentric three-layer cylinder model and performing analysis using electrostatic approximation. is doing.

According to a sixteenth aspect of the present invention, in the plasma density information measuring apparatus according to the thirteenth aspect, the correlation storing means comprises air, a dielectric, a plasma, an antenna which constitutes the plasma density information measuring probe. Based on the finite-difference time-domain method that obtains the time variation and domain variation of the electromagnetic field by gridding with the space coordinates, the reflectance of the frequency-dependent electromagnetic field is determined to obtain the basic absorption frequency And the plasma surface wave resonance frequency, which is a constant frequency that is observed regardless of the shape of the probe for measuring plasma density information, based on the finite difference time domain method. And a correlation of plasma density information having a constant correlation with the plasma surface wave resonance frequency. It is an feature.

[Operation / Effect] According to the sixteenth aspect of the present invention, the correlation storage means grids the air, the dielectric, the plasma, and the antenna, which constitute the probe for measuring plasma density information, in spatial coordinates. Based on the finite-difference time-domain method for obtaining the time change and the region change of the electromagnetic field, the basic absorption frequency and the plasma surface wave resonance frequency are obtained, and the above correlation is obtained and stored in advance.

According to a seventeenth aspect of the present invention, there is provided a plasma density information measuring device for measuring plasma density information indicating plasma characteristics, which is used for measuring plasma density information while sweeping a frequency to measure the plasma density information. A plasma density information measuring power supply for supplying electric power to plasma, a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the plasma density information measuring power by a plasma load, and the plasma density information measuring And a second output means for measuring the plasma density information a plurality of times using the probe for measuring and outputting each measurement result of the plasma density information over time.

[Operation / Effect] According to the seventeenth aspect of the invention, the plasma density information is measured a plurality of times by the second output means using the plasma density information measuring probe, and each of the plasma density information is measured. The measurement result of is output over time. Therefore, the plasma density information can be grasped for each time series.

The invention described in claim 18 is a plasma density information measuring device for measuring plasma density information indicating characteristics of plasma, for measuring plasma density information while sweeping a frequency to measure the plasma density information. A plasma density information measuring power supply for supplying electric power to plasma, a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the plasma density information measuring power by a plasma load, and the plasma density information measuring Plasma density information is measured multiple times using a probe for plasma, each measurement result of the plasma density information is obtained with respect to time, the value of the plasma density information at each time is integrated with respect to time, and the time of the plasma density information is integrated. And an integrated value deriving means for deriving.

[Operation / Effect] According to the invention as set forth in claim 18, the integrated value deriving means measures the plasma density information a plurality of times using the plasma density information measuring probe, and each of the plasma density information is measured. The measurement result is obtained with respect to time, the value of the plasma density information at each time is integrated with respect to time, and the time integration of the plasma density information is derived. Therefore, the time-integrated plasma density information can be grasped.

According to a nineteenth aspect of the present invention, the plasma density is measured based on the reflection or absorption of the plasma density information measuring power supplied to the plasma from the plasma density information measuring power source for measuring the plasma density information. A plasma density information measuring probe for measuring information, wherein one linear antenna configured to radiate electric power, a cable for transmitting the electric power for measuring plasma density information, and a tip coupled to plasma are closed. And a dielectric region, the cable and the antenna are covered by the dielectric region, the outer diameter of the dielectric region,
It is characterized in that the length of the antenna and the length from the connecting portion between the antenna and the cable to the tip of the dielectric region are substantially equal to each other.

[Operation / Effect] The length of one linear antenna that constitutes the probe for measuring plasma density information (hereinafter, abbreviated as “measurement probe” as appropriate) is calculated from the connecting portion between the antenna and the cable. If the length is shorter than the tip of the dielectric area, gas such as air is likely to be present between the tip of the antenna and the tip of the dielectric area, and the plasma coupling described below becomes worse. , The measurement resolution will decrease. Conversely, if the length of the antenna is longer than the length from the connection between the antenna and the cable to the tip of the dielectric area, if the antenna is linear, it will penetrate into the dielectric area. Will end up. Also, if the outer diameter of the dielectric region is shorter than the length of the measuring probe in the longitudinal direction, such as the length of the antenna or the length from the connection part to the tip of the dielectric region, a standing wave is generated. There are a plurality of certain plasma surface waves, and if the plasma surface wave absorption frequencies are excluded, the same number of absorption frequencies exist. On the contrary, if the outer diameter of the dielectric region is longer than the length of the measurement probe in the longitudinal direction, the number of standing waves is one, but the distance between the dielectric region coupled with the plasma and the antenna becomes long. Therefore, the measurement resolution is lowered and the absorption frequency cannot be observed.
Furthermore, when the antenna is linear and is not composed of one antenna, for example, in the case of a dipole antenna composed of two antennas or a bent antenna, a fixed antenna is used. There are a plurality of plasma surface waves that are standing waves. Therefore, the present inventors have conceived to configure a plasma density information measurement probe as follows.

According to the invention of claim 19 obtained based on the above knowledge, the power for measuring plasma density information (power for measuring) supplied from the power source for measuring plasma density information (power for measuring) ) Is transmitted via the cable of the measuring probe to the antenna, emitted from the antenna and absorbed by the plasma load, or reflected and returned via the cable. In other words, the plasma surface wave is excited in the dielectric area that is the surface of the measurement probe, and the measurement power supplied from the measurement power source is coupled with the plasma through the surface of the probe and is absorbed by the plasma load. Or reflections occur.

In such a measuring probe, the outer diameter of the dielectric region, the length of the antenna, and the length from the connecting portion between the antenna and the cable to the tip of the dielectric region are substantially equal to each other. Is configured. Moreover,
The antenna is formed in a linear shape and is also formed by one antenna. Therefore, there is only one plasma surface wave that is a standing wave, the measurement resolution is improved, and the absorption frequency is easily observed. Therefore, except the plasma surface wave absorption frequency, the absorption frequency depending on the shape of the probe is observed as only the basic absorption frequency, so that the basic absorption frequency can be easily specified only by measuring the point of absorption. As a result, the plasma density information can be easily grasped and the plasma processing can be easily performed. In addition, "the outer diameter of the dielectric region, the length of the antenna,
And the lengths from the connection between the antenna and the cable to the tip of the dielectric region are substantially equal to each other ”means that the dimensional difference between the individual lengths is within the range of −2 mm to +2 mm.

According to a twentieth aspect of the present invention, a computer-readable program recorded with a program for causing the computer to execute the plasma density information measuring method according to any one of the second to fourth aspects. It is a possible recording medium for measuring plasma density information.

[Operation / Effect] According to the invention described in claim 20, by causing a computer to execute the plasma density information measuring method according to claim 2 or any one of claims 4 to 9, The plasma density information can be easily grasped.

According to a twenty-first aspect of the present invention, there is provided a plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein a plasma density information measuring power is supplied while sweeping a frequency to measure plasma density information. From a power supply for measuring plasma density information supplied to plasma, a probe for measuring plasma density information based on reflection or absorption of the power for measuring plasma density information by a plasma load, and a power supply for measuring plasma density information The first frequency output means for outputting each addition / subtraction frequency which is each frequency obtained by adding or subtracting a predetermined frequency to each output frequency which is each swept frequency, and the plasma load. Each reflection which is each frequency of the reflected or absorbed plasma density information measuring power Second frequency output means for subtracting and adding each addition / subtraction frequency output from the first frequency output means to the wave number, and each frequency obtained by the second frequency output means. A frequency passing means for passing only a frequency that matches the value of the predetermined frequency among the above, and a first for outputting the electric power at the frequency passed by the frequency passing means as the reflected or absorbed electric power for measuring plasma density information. And output means and control means for controlling the plasma processing based on the measured plasma density information.

[Operation / Effect] According to the invention of claim 21, the plasma density information measuring power (measuring power) incident from the plasma density information measuring power source (measuring power source) is equal to the plasma density information. Via the measuring probe, it is absorbed by the plasma load due to the plasma density or is reflected back. Based on the reflection or absorption of the measuring power, the plasma density information is measured using the plasma density information measuring probe. Since the plasma density information indicates the characteristics of the plasma, the plasma processing is controlled by the control means by measuring the plasma density information.

At this time, the following actions and effects are achieved by additionally including the first and second frequency output means, the frequency passing means, and the first output means. That is, the first frequency output means outputs each addition / subtraction frequency obtained by adding or subtracting a predetermined frequency to or from each output frequency swept from the measurement power supply (plasma density information measurement power supply). . Then, the second frequency output means subtracts each of the above-mentioned addition / subtraction frequencies from each reflection frequency of the measurement power (power for plasma density information measurement) reflected or absorbed by the plasma load. As described in claim 1, the measurement power reflected by the plasma load also includes a noise component, and the reflection frequency of the measurement power is apparently
There are a plurality of frequencies including frequencies affected by noise. Also, the output frequency swept from the measurement power has the same value as the reflection frequency of the measurement power reflected when noise is not taken into account, so it is obtained by subtraction of the reflection frequency and the addition / subtraction frequency. Of the plurality of frequencies, the absolute value of the frequency obtained by the subtraction of the net reflection frequency and the addition / subtraction frequency that does not consider noise becomes the same value as the above-mentioned predetermined frequency.

Therefore, among the respective frequencies obtained by the second frequency output means, only the frequency obtained by the subtraction of the net reflection frequency and the addition / subtraction frequency without considering noise is determined by the frequency passing means. The signal is passed as if it coincides with the same value as the frequency of, and the power at the frequency at that time is output as the reflected component of the measurement power by the first output means. As a result, mixing of noise can be reduced, plasma density information can be easily grasped, and plasma processing can be easily performed.

According to a twenty-second aspect of the present invention, in the plasma processing apparatus according to the twenty-first aspect, the first output means relates to the plasma generation power output from the plasma generation power source for generating plasma. It is characterized in that it is provided with a harmonic wave removing means that does not output the frequency of the harmonic wave.

[Operation / Effect] According to the invention as set forth in claim 22, since the first output means is provided with the harmonic wave removing means, the output frequency is from the plasma generation power source for generating plasma. In the case where the frequency of the higher harmonic wave related to the output electric power for plasma generation matches, even if noise due to the higher harmonic wave is mixed, the frequency component in the higher harmonic wave is removed by the higher harmonic wave removing means and is output. As a result, since the harmonic noise is not output from the measurement result, the plasma density information can be more accurately grasped and the plasma processing can be performed more precisely.

According to a twenty-third aspect of the present invention, there is provided a plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein a plasma density information measuring power is supplied while sweeping a frequency to measure plasma density information. A power source for measuring plasma density information supplied to plasma, a probe for measuring plasma density information based on reflection or absorption of power for measuring plasma density information by a plasma load, and the measured plasma density information Control means for controlling the plasma processing based on the above, the power source for measuring plasma density information, the low-pass filter for passing the frequency of the low-pass side, and the current for driving the low-pass filter. An oscillating closed circuit controlled by the phase difference signal, comprising an electric current converting means for converting the phase difference signal. It is an butterfly.

[Operation / Effect] According to the invention of claim 23, the measuring power is output while sweeping the frequency from the measuring power supply, and the measuring power is supplied to the plasma for each frequency. An oscillation closed circuit controlled by a phase difference signal is used as this sweeping type power supply for measurement. This oscillating closed circuit includes a low-pass filter that passes a low-pass frequency and a current converter that converts a phase difference signal into a current for driving the low-pass filter. Therefore, the low-pass filter is driven by the current converted by the current converting means, and the time required for setting up the measurement power supply can be reduced as compared with the case of voltage driving. As a result, the plasma density information can be measured by sweeping the frequency from the power source for measurement before the plasma density information changes with time, and the plasma processing can be easily performed by the control means.

According to a twenty-fourth aspect of the present invention, there is provided a plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein a plasma density information measuring power is supplied while sweeping a frequency for measuring plasma density information. A power supply for measuring plasma density information supplied to plasma, a probe for measuring plasma density information based on reflection or absorption of the power for measuring plasma density information by plasma load, and a reflection or absorption by plasma load Of the plurality of absorption frequencies that are the resulting frequencies, the fundamental absorption frequency, which is the absorption frequency at the reflectance with the largest loss of power for measuring plasma density information due to reflection,
And a correlation storage unit that stores the correlation of the plasma density information in advance for each shape of the plasma density information measurement probe, and a control unit that controls the plasma processing based on the measured plasma density information. It is a feature.

[Operation / Effect] According to the invention as set forth in claim 24, the basic absorption frequency measured using the plasma density information measuring probe and the shape of each plasma density information measuring probe by the correlation memory are stored. The plasma density information is measured based on the correlation between the basic absorption frequency and the plasma density information stored in advance. Since the above correlation is stored in advance in the correlation storage means according to the shape of the probe, the plasma density information can be immediately measured only by measuring the fundamental absorption frequency. As a result, the plasma density information can be easily grasped and the plasma processing can be easily performed by the control means as compared with the conventional case.

According to a twenty-fifth aspect of the present invention, in the plasma processing apparatus according to the twenty-fourth aspect, the correlation storing means measures the basic absorption frequency for each shape of the plasma density information measuring probe, and the plasma density is measured. The result obtained by measuring the plasma surface wave resonance frequency, which is a constant frequency observed regardless of the shape of the information measuring probe, is a constant correlation with the fundamental absorption frequency and the plasma surface wave resonance frequency. It is characterized in that it is a correlation of the plasma density information.

[Operation / Effect] According to the invention described in claim 25, the correlation storage means has a basic absorption frequency dependent on the shape of the probe for measuring plasma density information, and a plasma surface wave resonance frequency independent thereof. Is measured and the above correlation is obtained and stored in advance.

According to a twenty-sixth aspect of the present invention, in the plasma processing apparatus according to the twenty-fourth aspect, the correlation storage means includes the probe for measuring plasma density information from the center toward the outside, the dielectric, Based on a geometrical analysis method in which a concentric three-layer cylindrical model laminated in plasma is modeled and analyzed using electrostatic approximation, basic absorption frequencies are obtained for the longitudinal length of the concentric three-layer cylindrical model. , The result obtained by obtaining the frequency that converges when the length of the concentric three-layer cylinder model in the longitudinal direction approaches 0 as the plasma surface wave resonance frequency,
It is characterized in that the basic absorption frequency and the plasma surface wave resonance frequency are set to a correlation of plasma density information having a constant correlation.

[Operation / Effect] According to the twenty-sixth aspect of the present invention, in the correlation storing means, the plasma density information measuring probe is laminated on the air, the dielectric and the plasma from the center to the outside. Based on the geometric analysis method of modeling into a concentric three-layer cylinder model and performing analysis using electrostatic approximation, the basic absorption frequency and the plasma surface wave resonance frequency are obtained, and the above correlation is obtained and stored in advance. is doing.

According to a twenty-seventh aspect of the present invention, in the plasma processing apparatus according to the twenty-fourth aspect, the correlation storage means includes air, a dielectric, a plasma, and an antenna which form the probe for measuring the plasma density information. Obtain the basic absorption frequency for each shape of the probe for measuring plasma density information by obtaining the frequency-dependent reflectance of the electromagnetic field based on the finite difference time domain method that obtains the time change and area change of the electromagnetic field by gridding with coordinates Along with, the plasma surface wave resonance frequency, which is a constant frequency observed regardless of the shape of the plasma density information measurement probe, the result obtained by obtaining based on the finite difference time domain method, the basic absorption frequency and the It is characterized in that it is a correlation of plasma density information that has a constant correlation with the plasma surface wave resonance frequency. Is shall.

[Operation / Effect] According to the twenty-seventh aspect of the present invention, the correlation storage means grids the air, the dielectric, the plasma, and the antenna, which form the probe for measuring plasma density information, in spatial coordinates. Based on the finite-difference time-domain method for obtaining the time change and the region change of the electromagnetic field, the basic absorption frequency and the plasma surface wave resonance frequency are obtained, and the above correlation is obtained and stored in advance.

The invention as set forth in claim 28 is a plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein a plasma density information measuring power is supplied while sweeping a frequency for measuring plasma density information. Power source for measuring plasma density information supplied to plasma, probe for measuring plasma density information based on reflection or absorption of power for measuring plasma density information by plasma load, and probe for measuring plasma density information Second output means for measuring plasma density information a plurality of times by using, and outputting each measurement result of the plasma density information over time, and control for controlling plasma processing based on the measured plasma density information. And means.

[Operation / Effect] According to the invention described in claim 28, the plasma density information is measured a plurality of times by the second output means using the plasma density information measuring probe, and each of the plasma density information is measured. The measurement result of is output over time. Therefore, the plasma density information can be grasped for each time series, and the plasma processing can be easily performed by the control means.

According to a twenty-ninth aspect of the present invention, there is provided a plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein plasma density information measuring power is supplied while sweeping a frequency to measure plasma density information. Power source for measuring plasma density information supplied to plasma, probe for measuring plasma density information based on reflection or absorption of power for measuring plasma density information by plasma load, and probe for measuring plasma density information Plasma density information is measured multiple times using, and each measurement result of the plasma density information is obtained with respect to time.
An integrated value deriving unit that integrates the values of the plasma density information at each time with respect to time and derives the time integration of the plasma density information, and a control unit that controls the plasma processing based on the derived integrated value. It is characterized by that.

[Operation / Effect] According to the invention as set forth in claim 29, the integrated value deriving means measures the plasma density information a plurality of times by using the plasma density information measuring probe, and each of the plasma density information The measurement result is obtained with respect to time, the value of the plasma density information at each time is integrated with respect to time, and the time integration of the plasma density information is derived. Therefore, the time-integrated plasma density information can be grasped, and the plasma processing can be easily performed by the control means based on the time-integrated plasma density information.

For example, when the plasma treatment is plasma etching, the film thickness to be etched is, when the plasma treatment is plasma CVD (chemical vapor deposition), the film thickness deposited is relative to the above-mentioned integrated value. Are correlated. Therefore, by grasping the plasma density information accumulated over time, it is possible to grasp the state of the plasma in performing the plasma processing, and the plasma density information accumulated over time,
That is, the plasma processing can be easily performed based on the integrated value.

[0084]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a plasma processing apparatus used in a probe for measuring plasma density information according to the present invention.

As shown in FIG. 1, the plasma processing apparatus according to the first embodiment includes a chamber 1 in which plasma PM is generated.
And an electrode 2 connected to a processing voltage (not shown) is disposed in the chamber 1.
A substrate W, which is an object to be processed, is placed on the electrode 2. By applying a processing voltage to the electrode 2, the plasma processing of the substrate W is performed.

The plasma treatment is not particularly limited as long as it is a treatment generally performed by plasma, such as plasma etching, plasma CVD or plasma ashing. In addition, the chamber 1 according to the first embodiment is
The so-called CCP (Capacitively Coupled Plas) that generates plasma between the two electrodes by making the two electrodes face each other.
sma) type, that is, a so-called ICP (Inductively C) that generates a magnetic field in the antenna by passing a current through an antenna equipped with a capacitively coupled plasma or a coil and generates an induction electric field by the magnetic field from the antenna.
The chamber may be a chamber used for a non-magnetic field plasma such as an coupled plasma (Oupled Plasma) type, that is, an inductively coupled plasma, or a chamber used for a magnetic field plasma such as an ECR (Electron Cyclotron Resonance) plasma.

The electrodes and the generating power source 3 for generating the plasma PM are connected via the generating power control unit 4, and the generating power control unit 4 causes the generating power source 3 to be generated.
The generation electric power supplied from the chamber to the chamber 1 is operated.
The generation power control unit 4 corresponds to the control means in the present invention.

In addition to the substrate described above, a measurement probe 5 for measuring plasma density information in the chamber 1 is inserted in the chamber 1, and a measurement power source 6 for measuring the plasma density information is provided. , What is this measuring probe 5?
It is connected via the coaxial cable 7 and the probe controller 8. In the first embodiment, the electron density is measured as the plasma density information, but other plasma density information includes, for example, the plasma density and the ion density.
The measurement probe 5 and the measurement power supply 6 respectively correspond to the plasma density information measurement probe and the plasma density information measurement power supply of the present invention.

In addition to the substrate W, the electrode 2, and the measurement probe 5 described above, the chamber 1 and the gas supply source (tank) 9 for supplying the gas for generating the plasma PM are provided with the gas adjusting valve 10. Connected via and.

Next, a specific configuration of the power generation control section 4 will be described. The power control unit 4 for generation includes an electron density setting unit 11 and an impedance matching device 12. The electron density setting unit 11 sets a target electron density, and if the actual electron density in the plasma PM generated in the chamber 1 and the set target electron density have a certain error or more. , The target electron density is reset. The impedance matching device 12 regulates the supply of the generation power to the chamber 1 to generate the chamber 1.
The electron density in the plasma PM generated therein is set to the set target electron density.

As the impedance matching device 12, when the frequency of the power source 3 for generation is a frequency on the order of MHz, a matching circuit combining an inductance and a capacitance is used. When the above-mentioned frequency is 1 GHz or more, an EH tuner or a stub tuner is used.

Next, the measuring probe 5 will be described with reference to FIG. The measurement probe 5 is formed by processing and molding the tip of the coaxial cable 7. As shown in FIG. 2, after removing the outer insulator 7a and the outer conductor 7b of the coaxial cable 7 at the tip, It is configured by covering a dielectric tube 13 having a closed tip. Further, by removing the outer insulator 7a and the outer conductor 7b, only the center insulator 7c and the center conductor 7d are left at the tip of the coaxial cable 7,
The center conductor 7d will function as an antenna that radiates the electric power transmitted through the coaxial cable 7. Therefore, the central conductor 7d at the tip portion corresponds to the antenna in the present invention, the coaxial cable 7 corresponds to the cable in the present invention, and the tube 13 corresponds to the dielectric region in the present invention.

In the plasma PM, so-called plasma contamination occurs in which a product generated by the plasma atmosphere adheres to an antenna or the like and causes a measurement error.
In terms of preventing the antenna from such plasma contamination, the central insulator 7c and the tube 13 are provided outside the antenna.
The central insulator 7 even if both are not necessarily covered
Any one of the c and the tube 13 may be covered.

The tube 13 is made of quartz (SiO ₂ ) having a relative dielectric constant of about 4 in this embodiment. The material forming the tube 13 has, for example, a relative dielectric constant of 2
Fluororesin, relative permittivity of 10 alumina (Al ₂ O ₃ ), relative permittivity of 35 zirconia (ZrO ₂ ), anisotropic dielectric, and relative permittivity depending on purity. Although it is not particularly limited such as silicon carbide (SiC) whose relative dielectric constant is about 20 although the dielectric constant changes, considering that it is easy to form the tube 13 in the case of a solid dielectric, It is preferable that the tube 13 is formed of a material having a relative dielectric constant of 2 to 50.

The outer diameter of the tube 19 is φ. Further, the length of the central conductor 7d at the tip portion which is the antenna is L as shown in FIG. The length from the location where the external insulator 7a and the external conductor 7b are removed to the tip of the tube 19 is d, as shown in FIG. The location where the outer insulator 7a and the outer conductor 7b are removed is also the connecting portion between the central conductor 7d, which is an antenna, and the coaxial cable 7. Therefore, the length L of the central conductor 7d at the tip corresponds to the length of the antenna in the present invention, and the length d from the location where the outer insulator 7a and the outer conductor 7b are removed to the tip of the tube 19. Corresponds to the length from the tip of the dielectric outer cover to the connection between the antenna and the cable in the present invention.

The outer diameter φ of the tube 13, the length L of the antenna, the length d from the location where the outer insulator 7a and the outer conductor 7b are removed to the tip of the tube 13 (hereinafter referred to as "from tip to tip as appropriate"). (Abbreviated as "length to part d") is 1 cm, and the respective lengths are equal. The above φ, L, and d do not necessarily have to be configured to be substantially equal, but as will be described later, the fundamental absorption frequency (0 which is the absorption frequency at the reflectance with the largest loss, that is, the largest Q factor (quality factor).
From the viewpoint of easily specifying the next absorption frequency, it is preferable that they are formed to be substantially equal. As mentioned in "Means for solving problems", "almost equal" means
It indicates that the dimensional difference between individual lengths falls within the range of −2 mm to +2 mm. Further, although depending on the size of the chamber 1 and the like, it is preferable that the above φ, L, and d are dimensions that are within 5 cm.

The measuring probe 5 as shown in FIG. 2 configured as described above is inserted into the plasma PM. next,
The measurement power is transmitted from the measurement power supply 6. Then, at the absorption frequency of the measurement probe 5, resonance absorption occurs at the tip while the tube 13, the coaxial cable 7, etc. are held as boundary conditions. As a result, the electromagnetic wave supplied and transmitted from the measurement power source 6 is absorbed, and the reflected power becomes small at the absorption frequency of the measurement probe 5. When the measurement power is absorbed by the plasma PM, the remaining measurement power that is not absorbed goes to the measurement power supply 6 side in the direction opposite to the direction in which it is transmitted from the measurement power supply 6 side to the plasma PM side. Transmitted. Also, the measuring power is plasma P
When reflected by M, the reflected measurement power is similarly transmitted toward the measurement power supply 6 side. This measuring power corresponds to the plasma density information measuring power in the present invention.

Next, the specific structure of the probe controller 8 will be described. The probe controller 8 includes a directional coupler 14, an attenuator 15, and a filter 16 as shown in FIG.
A frequency output unit 17, a double balanced mixer (DBM) 18 (hereinafter abbreviated as "DBM"), and a band pass filter (BPF).
(Band Pass Filter) 19 (hereinafter, appropriately abbreviated as “BPF”), a first output device 20 including an absorption frequency derivation unit described later, and an electron density conversion unit 21. The first output device 20 includes an absorption frequency derivation unit 20a, a harmonic wave removal unit 20b, and a display monitor 20c.

A directional coupler 14, an attenuator 15 and a filter 16 are connected to the measurement probe 5 via a coaxial cable 7 in this order from the measurement power source 6 and the DBM 18. In addition, the directional coupler 16 includes the first output device 2
BPF1 in order from the absorption frequency derivation unit 20a side in 0.
9, DBM18 is connected and DBM18
And the measuring power supply 6 through the frequency output unit 17, and the absorption frequency deriving unit 20a and the generating power supply 3 include the harmonic wave removing unit 20b.
Via the absorption frequency deriving unit 20a and the electron density setting unit 11
And are respectively connected via the electron density converter 21. The first output device 20 is the first output device of the present invention.
Corresponds to the output means of.

The power supply 6 for measurement is a frequency sweep type, and an oscillation closed circuit (PLL) described later is used as the power supply 6 for measurement. The measuring power supply 6 is arranged in a certain frequency band (for example, 10
Output power while automatically sweeping measurement power at a frequency of 0 kHz to 2.5 GHz). The measurement power output from the measurement power supply 6 is transmitted to the measurement probe 5 via the directional coupler 14, the attenuator 15, and the filter 16 in this order while being transmitted through the coaxial cable 7. On the other hand, when the power for measurement is absorbed or reflected, the reflected component of the power is transmitted in the opposite direction as described above, is detected by the directional coupler 14, and is output via the DBM 18 and the BPF 19 as the first output. It is sent to the absorption frequency derivation unit 20a in the device 20. The frequency of the measurement power output from the measurement power supply 6 is also sequentially sent to the absorption frequency derivation unit 20a.

The filter 16 has a function of removing electric power and noise mixed in the probe controller 8. In addition,
The filter 16 of the first embodiment includes a high pass filter (H
PF (High Pass Filter) is used. Further, the attenuator 15 has a function of adjusting the amount of the measurement power sent to the measurement probe 5.

The frequency output unit 17 outputs only a predetermined frequency Δf _{1 with} respect to the frequency swept from the measurement power source 6 (hereinafter, the frequency swept from the measurement power source 6 is referred to as “output frequency f ₀ ”). Performs the function of adding or subtracting and outputting. In this specification, the frequency output at the time of addition is defined as “addition frequency (f ₀ + Δf ₁ )”, and the frequency output at the time of subtraction is defined as “subtraction frequency (f ₀
-Δf ₁ ) ”. The frequency output unit 17 corresponds to the first frequency output means in the present invention.

The DBM 18 (double balanced mixer 18) outputs the measurement power output from the measurement power source 6 and the power of the reflected component absorbed and reflected by the plasma PM, and the frequency output unit 17. It acts as a multiplier that multiplies with power. Therefore, between the phases of the electric power, the phase is added or subtracted by the DBM 18, and the frequency is of course also added or subtracted by the DBM 18. Further, the DBM 18 subtracts the addition frequency (f ₀ + Δf ₁ ) or the subtraction frequency (f ₀ −Δf ₁ ) from the reflected frequency (hereinafter, this reflected frequency is referred to as “reflection frequency”). DBM18
Corresponds to the second frequency output means in the present invention.

The BPF 19 (bandpass filter 19) is
It fulfills the function of passing only the frequency that matches the value of the above-mentioned predetermined frequency. The BPF 19 corresponds to the frequency passing means in the present invention.

The absorption frequency deriving unit 20a obtains the change in the reflectance of the measuring power with respect to frequency based on the frequency of the measuring power and the detected reflection amount of the measuring power. Then, based on the obtained results, the absorption frequency at which strong measurement power absorption occurs due to the electron density is obtained. Further, the output result is output and displayed on the display monitor 20c. In addition,
Specific derivation of the absorption frequency will be described in a flowchart described later.

The harmonic wave removing section 20b has a function of passing and outputting the frequency component of the harmonic wave generated when the generation power output from the generation power supply 3 is supplied to the chamber 1. The harmonic wave removing unit 20b corresponds to the harmonic wave removing means in the present invention. Further, the harmonic wave removing unit 20b is
The recording medium includes an OM and the like. The harmonic removing unit 20b may be a BPF (band pass filter) as described above, other than the recording medium, and the BPF may have a function of removing harmonic components. Since there are the same number, it is necessary to have the same number of BPFs. Further, since the application is not effective when the frequency of the generation power output from the generation power supply 3 is changed, it is preferable to configure the harmonic removing section 20b with the above-mentioned recording medium. The specific function of the harmonic wave removing unit 20b will also be described with reference to the flowchart described later.

The electron density conversion section 21 is configured to convert the electron density based on the absorption frequency obtained by the absorption frequency derivation section 20a. Since the above-mentioned absorption frequency has a certain correlation with the electron density, the electron density can be easily obtained by finding the absorption frequency.

Next, the oscillation closed circuit (P
LL) will be described with reference to FIG. The measurement power supply 6 (PLL6) includes a phase comparator 22, a current conversion amplifier 23, and a low pass filter (LPF (Low Pass Filter)).
ter)) 24 (hereinafter appropriately abbreviated as “LPF”),
Voltage Controlled Oscilla (VCO)
tor)) 25 (hereinafter appropriately abbreviated as “VCO”),
And a programmable divider 26.

The phase comparator 22 has a reference frequency, that is, a reference frequency f _ref and each output frequency f ₀ swept.
And the phase difference signal obtained by the comparison are applied to the amplifier 23 for current conversion. The phase difference signal is also a signal related to voltage.

The amplifier 23 converts the phase difference signal, which is also the voltage signal output from the phase comparator 22, into a current and converts it to L.
The function is given to the PF 24 and further drives the LPF 24. The amplifier 23 corresponds to the current conversion means in the present invention.

The LPF 24 has a function of passing a frequency on the low frequency side, converting it into a voltage, and giving the voltage to the VCO 25.

The VCO 25 outputs a frequency according to the magnitude of the voltage from the LPF 24 and sweeps the output frequency as each output frequency f ₀ .

The programmable divider 26 divides the output frequency f ₀ output from the VCO when the division ratio is set to N, and gives the divided frequency (f ₀ / N) to the phase comparator 22. Perform a function.

For example, when the output frequency f ₀ is f _ref , the programmable divider 26 is counting "1",
The division ratio is 1. Then, the divided frequency is (f ₀ / N) (=
f _ref = 1 = f _ref ) and the reference frequency f _ref are compared by the phase comparator 22, and the resulting phase difference signal is sent to the amplifier 23 and converted into a current signal by the amplifier 23. Let Then, the LPF 24 is driven by the current signal, passes only the frequency on the low frequency side, and is sent to the VCO 25. The VCO 25 outputs the output frequency f ₀ as 2f _ref . At this time, the programmable divider 26 is counting "2", and the frequency division ratio is 2. By repeating the same procedure a plurality of times, each output frequency f ₀ is swept output as follows. That is, the phase comparator 2
2 amplifier 23~LPF24~VCO25~ programmable divider 26 to the time that the phase comparator 22 a round (loop), the output frequency f ₀ is f _ref, 2f _ref, 3
It is swept in order of f _ref , ....

Next, the flow of plasma processing in the plasma processing apparatus having the above-mentioned structure will be described with reference to the flowchart of FIG. At the time of step S1, the switch of the generation power source 3 for plasma generation is already in the ON state, the gas is already supplied from the gas supply source (tank) 9 into the chamber 1, and the plasma PM is also already generated. It is assumed that The frequency band output from the power supply 6 for measurement is in the range of 100 kHz to 2.5 GHz, and the frequency is swept every 100 kHz, and the frequency output from the power supply 3 for generation is 13.56 MHz. In addition, a frequency of 140 MHz is used as the predetermined frequency used in the frequency output unit 17, and
As F19, a 140 MHz BPF that passes only the frequency of 140 MHz is used.

[Step S1] The measuring power source 6 is turned on. 1. From measurement power source 6 to 100 kHz
Outputs while automatically sweeping measurement power at frequencies up to 5 GHz. In addition, the absorption frequency derivation unit 2 while automatically sweeping
The above frequency is sequentially sent to 0a. The output measurement power is supplied to the measurement probe 5 via the coaxial cable 7.

Further, since the measuring power supply 6 sweeps and outputs every 100 kHz at frequencies from 100 kHz to 2.5 GHz, the reference frequency f _ref is 100 kHz and each output frequency f ₀ is 100 kHz, 200 kHz, ...,
It is swept in sequence with 2.5 GHz. First, a case where the output frequency f _{0 of} 100 kHz is swept will be described as an example.

When the output frequency f _{0 of} 100 kHz is swept from the measurement power supply 6, the measurement power is sent to the absorption frequency deriving section 20a, and the measurement power at the output frequency f ₀ of 100 kHz is measured via the coaxial cable 7. 5 is supplied to the frequency output unit 17 at 100 kHz.
Output frequency f ₀ of Then, the following step S2 (supplying the measuring power to the plasma and detecting the reflected power) and step S3 (outputting the frequency f ₀ + Δf ₁ from the frequency output section) are performed almost at the same time. First, step S2 will be described.

[Step S2] The supplied measuring power is absorbed or reflected by the surface wave, and the reflected amount of the measuring power is passed through the coaxial cable 7 in the opposite direction to that at the time of supplying the measuring power 6 side. Be transmitted to. The reflection amount of the measurement power is detected by the directional coupler 14 via the filter 16, the attenuator 15, and the directional coupler 14 in this order.
Steps S1 to S2 correspond to the process (a) in the present invention.

[Step S3] The frequency output unit 17 receives 10
When the output frequency f _{0 of 0} kHz is sent in, a predetermined frequency is added or subtracted and output. In this step, when addition is performed, that is, the addition frequency (f ₀
+ Δf ₁ ) will be described as an example. Then, since the predetermined frequency Δf ₁ is 140 MHz, the predetermined frequency Δf ₁ is added to the output frequency f ₀ of 100 kHz. As a result, from the frequency output unit 17, 100 kHz
A frequency of +140 MHz (= 140.1 MHz) is output.

[Step S4] The electric power for measurement detected by the directional coupler 14 (processed in step S2) is
With noise superimposed on the reflected power, DBM1
In step 8, the electric power output from the frequency output unit 17 (processed in step S3) is multiplied and added or subtracted between frequencies. Since the reflected frequency reflected includes noise as described above, not only for the frequency of 100 kHz output from the measurement power source 6 and reflected, but also for various reflected frequencies due to noise,
100 kHz + 140 MHz, which is the frequency f ₀ + Δf ₁
(= 140.1 MHz) is subtracted. Therefore, there are a plurality of frequencies obtained by subtraction by the DBM 18.

The BPF 19 filters the electric power at each frequency obtained by the subtraction by the DBM 18.

As described above, since the BPF 19 passes only the frequency that matches the value of the predetermined frequency Δf ₁ (= 140 MHz), each frequency obtained by the subtraction by the DBM 18 has the value of the predetermined frequency Δf ₁ . The BPF 19 determines whether or not

In this case, the frequency obtained by subtracting 100 kHz + 140 MHz (= 140.1 MHz) by the DBM 18 from the frequency of 100 kHz output from the measuring power source 6 and reflected is 100 kHz− (100 kHz +
140 MHz), that is, -140 MHz, this frequency (absolute value) is a predetermined frequency Δf ₁ (= 140 MH).
Since it coincides with the value of z), only the electric power at the frequency of 100 kHz output from the measuring power supply 6 and reflected is passed. Since the other reflection frequencies due to the influence of noise do not match, the power at the other reflection frequencies, that is, the noise, is removed by the BPF 19.

[Step S5] Since the frequency passed by the BPF 19 remains −140 MHz, the output frequency f ₀ (= 100 kHz) output from the measuring power supply 6 is output.
calibrate to z) and return. The absorption frequency deriving unit 20a plots the calibrated output frequency on the horizontal axis, and the detected reflection amount of the measurement power ([detection reflection amount of measurement power] / [total output amount of measurement power]) at that time is shown vertically. Display output for axis.

On the other hand, the frequency output from the generation power source 3
Number of harmonics (13.56 MHz in the case of the first embodiment)
The frequency at 1 is sent to the harmonic wave removing unit 20b. Output frequency
Number f ₀And see if the harmonic frequencies match,
The harmonic removing unit 20b determines whether or not to output.

Although the noise is removed by the BPF 19 in step S4, the noise due to the higher harmonic wave is removed by the BPF 19.
Neither is removed by 19. When the frequency output from the generation power source 3 is 13.56 MHz as an example, the generation power of 13.56 MHz is supplied to the plasma PM in the chamber 1. At this time, harmonics of the power for generation due to the plasma PM load are superimposed on the reflected power for measurement as noise. The harmonic of the power for generation is 1
3.56MHz, 27.12MHz (= 2 x 13.56)
MHz), 40.68 MHz (= 3 x 13.56 MH
z), ... and an integral multiple of the frequency.

Therefore, when the output frequency f ₀ swept from the measuring power supply 6 matches the frequency of the harmonic of the generation power, the noise due to the harmonic is superposed,
It passes through the BPF 19 and is output as the amount of reflection of the measuring power. The output frequency f ₀ is the reference frequency f
_ref (= 100 kHz) and power generation frequency 13.5
Noise is superimposed at a common multiple of 6 MHz. That is, the output frequency f ₀ is 67.8 MHz (= 5 × 13.
56MHz), 135.6MHz (= 10 × 13.56)
MHz), 203.4 MHz (= 15 × 13.56 MH
z), 271.2 MHz (= 20 × 13.56 MH
When z), ..., Noise is superimposed.

A state in which noise is superimposed will be described with reference to FIG. FIG. 5A is a waveform diagram showing a change in reflectance of the measurement power output when noise is superimposed, and FIG. 5B is a waveform diagram showing the harmonics removed by the harmonic removing unit 20b. 5 is a waveform diagram showing a change in reflectance of the measuring power with respect to frequency when no output is performed for the frequency in FIG. Black circles in FIG. 5 are plots in which the output frequency to be swept and the reflectance of the measurement power are associated with each other. Figure 5
When the noise N in (a) is output at the output frequency of 135.6 MHz, the harmonic wave removing unit 20b does not pass and output about 135.6 MHz. As a result, as shown in FIG. 5B, the reflectance of the measuring power at frequencies 135.5 MHz and 135.7 MHz before and after 135.6 MHz is output, but it is 135.6 MHz.
The reflectance of the measuring power including the noise N at is not output. Therefore, 135.5MHz, 135.7MHz
The data obtained by connecting the plots of (2) becomes the reflectance of the measurement power, and this data is output without including noise at 135.6 MHz.

As described above, the recording medium constituting the harmonic wave removing section 20b reads the frequency output from the generating power supply 3 and the reference frequency f _ref from the measuring power supply 6. When the output frequency is a common multiple of the reference frequency f _ref and the frequency of the power for generation, the function of passing the frequency, that is, the noise portion and not displaying the output is fulfilled.

[Step S6] As described above, the harmonic elimination section 20b passes the frequency of the harmonic, and the output result is sent to the absorption frequency deriving section 20a. If the sweep is not performed for all output frequencies f ₀ , the procedure from step S1 to step S6 is similarly repeated for other output frequencies f ₀ . If all the output frequencies f ₀ are swept, and if the output frequency is 2.5 GHz in the case of the first embodiment, the process jumps to the next step S7.

[Step S7] FIG. 6 shows the result of the reflectance of the measuring power whose frequency has been swept. Note that FIG. 6 is a diagram swept from 100 kHz to 3.0 GHz, and shows the outer diameter φ of the tube 13 in the measurement probe 5, the length L of the antenna, and the length d from the tip to the connection (FIG. 2). Is a graph in the case where they are not equal.

In FIG. 6, two absorption points Pa and Pb appear. Normally, a plurality of absorption points appear, and accordingly, the same number of absorption frequencies as the absorption points exist. These absorption frequencies have a certain correlation with plasma density information such as electron density. In particular, among the absorption frequencies, the absorption frequency proportional to the square of the electron density is the plasma surface wave resonance. It is called frequency. This plasma surface wave resonance frequency is a useful physical quantity when deriving plasma density information such as electron density.
Is one. Since the plasma density information such as the electron density changes locally, it is preferable that the measurement probe 5 perform the measurement near the surface of the substrate W.

Further, since the plasma surface wave resonance frequency is a high-order absorption frequency, its absorption is small and it is difficult to observe it in FIG. Therefore, the absorption point P at the most basic absorption frequency (0th-order absorption frequency)
b is measured. In the case of FIG. 6, absorption points Pa and P
Since the absorption difference with b is remarkable, the absorption point Pb
The absorption frequency at can be specified as the basic absorption frequency, but if it is difficult to specify due to noise, etc.,
When the measurement probe 5 is configured such that the outer diameter φ of the tube 13, the length L of the antenna, and the length d from the tip portion to the connection portion (see FIG. 2) are substantially equal to each other, plasma that is a standing wave is generated. Since there is only one surface wave, there is only one absorption point Pb except the plasma surface wave absorption frequency. Therefore, the fundamental absorption frequency can be easily specified only by measuring the absorbed point Pb.

[Step S8] When the absorption frequency is derived by the absorption frequency deriving unit 20a, the electron density converting unit 2
It is converted into an electron density by 1 and is derived. Steps S3 to S8 are (b) in the present invention.
Corresponds to the process of.

[Step S9] When the electron density is obtained by the electron density converter 21, the electron density thus obtained is sent to the electron density setting unit 11, and the electron density actually obtained, that is, the electron density converter 21 is used. The electron density setting unit 11 determines whether the obtained electron density and the target electron density match.

If the difference between the target electron density and the actually obtained electron density is smaller than a predetermined value, it is considered that the set target electron density has been reached and the step S is performed.
Plasma treatment is performed by jumping to 11. If the difference between the target electron density and the actually obtained electron density is larger than the predetermined value, the process jumps to step S10.

[Step S10] The supply of the generation power to the chamber 1 is adjusted to operate the impedance matching box 12 so that the electron density becomes the set target electron density (for example, the position of the tuner is changed). . Then, returning to step S1, the process is repeated until the actually obtained electron density reaches the target electron density.

[Step S11] If the set target electron density is reached, plasma processing is performed. Specifically, the substrate W is put into the chamber 1 and placed on the electrode 2. For example, by applying a processing voltage to the electrode 2, ions and electrons in the plasma PM reach the surface of the substrate W, and plasma processing of the substrate W such as etching is performed.

The above steps S1 to S11 are the flow of plasma processing. In such plasma processing, the plasma processing apparatus according to the first embodiment has the following effects.

The probe control unit 8 includes a frequency output unit 17, a DBM 18 and a BPF 19, and the frequency output unit 17
Output by adding or subtracting a predetermined frequency Δf _{1 to} or from the output frequency f ₀ output from the measurement power source 6, and the DBM 18 determines the frequency output unit from the reflection frequency of the power reflected by the plasma load PM. The frequency f ₀ + Δf ₁ or f ₀ −Δf ₁ output by 17 is subtracted to obtain the BPF.
This is a heterodyne system in which only the frequency matching the predetermined frequency is passed by 19. The output frequency f ₀ swept from the measurement power supply 6 has the same value as the reflection frequency of the measurement power reflected when noise is not taken into consideration. Therefore, the net reflection frequency (= output frequency) without taking noise into consideration The frequency (f ₀ −) obtained by subtracting f ₀ ) from the frequency (f ₀ + Δf ₁ ) or the frequency (f ₀ −Δf ₁ ).
The absolute value of (f ₀ + Δf ₁ )) or (f ₀ − (f ₀ −Δf ₁ )), that is, the absolute value of the frequency Δf ₁ or −Δf ₁ becomes the same value as the predetermined frequency Δf ₁ .

Therefore, of the plurality of frequencies obtained by subtraction of the reflection frequency and the frequency f ₀ + Δf ₁ or f ₀ −Δf ₁ output by the frequency output unit 17, the net reflection frequency (= Output frequency f ₀ ) and frequency f ₀ +
Only the absolute value of the frequency obtained from the subtraction with Δf ₁ or f ₀ −Δf ₁ matches as the same value as the predetermined frequency Δf _1, and only the subtracted frequency is passed by the BPF 19, It is output as a reflected component of the measurement power. As a result, it is possible to reduce the mixing of noise and easily grasp the electron density, which is the plasma density information.

Furthermore, the output frequency f ₀ is equal to the generation power 3
When it matches the frequency of the harmonic related to the power for generation output from the harmonic removing unit 20b, the harmonic removing unit 20b does not pass and output the harmonic. As a result, since no harmonic noise is output from the measurement result, it is possible to more accurately grasp the electron density, which is the plasma density information.

Of course, when the fundamental absorption frequency and the harmonic frequency described above are coincident, the measurement of the fundamental absorption frequency is hindered, but the harmonic frequency has a very narrow spectrum width, that is, Q. Since the value is high, it is unlikely to cause a problem in measuring the fundamental absorption frequency. Further, since the electron density, which is the plasma density information, continuously changes, it is possible to determine it from the context.

Further, the measuring power source 6 is an oscillation closed circuit (PL
L), and since the LPF 24 (see FIG. 3) provided in the PLL is driven by current driving, the time required to set up the measurement power supply 6 can be reduced as compared with the case of voltage driving. it can. As a result, the electron density or the like, which is the plasma density information, can be easily measured by sweeping the frequency from the measurement power source 6 before the electron density, which is the plasma density information, changes with time. Can be grasped.

Further, as described above, preferably φ,
Measurement probe 5 so that L and d are approximately equal
By configuring, the gas such as air is not present between the tip of the antenna, which is the central conductor 7d at the tip, and the tip of the tube 13, and the distance between the tube 13 that couples with the plasma PM and the antenna is reduced. The absorption frequency can be measured without shortening the measurement resolution while the plasma surface wave that is a standing wave is one and remains short. Therefore, there is only one absorption point Pb (see FIG. 6) except the plasma surface wave absorption frequency. As a result, the fundamental absorption frequency can be easily specified only by measuring the absorbed point Pb.

In the apparatus of the first embodiment thus constructed, since the power control section 4 for generation is provided, the plasma processing can be easily performed. Further, since the noise due to the harmonics is not output by the harmonic wave removing unit 20b, the electron density, which is the plasma density information, can be grasped more accurately, and the plasma treatment can be performed more precisely.

[Second Embodiment] Next, a second embodiment of the present invention will be described. FIG. 7 is a block diagram showing a schematic configuration of the plasma processing apparatus according to the second embodiment. The same parts as those of the apparatus of the first embodiment are designated by the same reference numerals, and the illustration and description of the parts are omitted.

In the plasma processing apparatus according to the second embodiment,
A correlation memory 27 is provided. The correlation memory 27 stores in advance the correlation between the basic absorption frequency and the electron density for each shape of the measurement probe 5, and the data of the basic absorption frequency sent from the absorption frequency deriving unit 20a is stored in the electron density conversion unit. The above correlation stored in the correlation memory 27 is read out and converted from the basic frequency to the electron density. The correlation memory 27 is
It corresponds to the correlation storage means in the present invention. The correlation memory 27 is a recording medium including a ROM and the like. The specific function of the correlation memory 27 will be described later with reference to a flowchart.

Subsequently, in the plasma processing apparatus according to the second embodiment having the above-mentioned configuration, the flow of plasma processing will be described with reference to the flowchart of FIG. 8 and the correlation stored in the correlation memory 27 will be described. The flow until obtaining the relationship will be described with reference to the flowchart in FIG. With respect to the flowchart of FIG. 8, steps S1 to S6 and steps S8 to S11 in the flowchart according to the first embodiment are the same, so description thereof will be omitted.

[Step S7a] Absorption frequency deriving unit 20
The fundamental absorption frequency is obtained by a. This step S7
“A” corresponds to the fundamental frequency measurement process of (ab2) in the present invention.

[Step S8a] When the fundamental absorption frequency is derived by the absorption frequency deriving unit 20a, the fundamental absorption frequency is sent to the electron density converting unit 21 and stored in the correlation memory 27 in advance. Read the correlation. The electron density conversion unit 21 converts the electron density based on the basic absorption frequency obtained by the absorption frequency derivation unit 20a and the correlation between the basic absorption frequency and the electron density. Then, this step S8a corresponds to the plasma density information measuring step of (ab3) in the present invention.

Next, the correlation stored in advance in the correlation memory 27 will be described.

[Step S20] The fundamental absorption frequency is measured for each shape of the measurement probe 5. The fundamental absorption frequency is
Since it depends on the shape of the measurement probe 5, there are as many fundamental absorption frequencies as the shape pattern. This step S29 corresponds to the process of (AB1) in the present invention.

[Step S21] The plasma surface wave resonance frequency is measured. Specifically, for example, the fundamental absorption frequency is changed by changing the length of the antenna, and when the length of the antenna approaches 0 without limit, a plurality of absorption frequencies including the fundamental frequency converge to a certain frequency. The converged absorption frequency when the length of the antenna approaches 0 without limit is regarded as the plasma surface wave resonance frequency and measured. With the same method, for example, by changing the magnitude of the power for generation, the plasma density information such as the electron density changes.
The fundamental absorption frequency and the plasma surface wave resonance frequency are measured by changing the magnitude of the power for generation. Since the plasma surface wave resonance frequency does not depend on the shape of the measurement probe 5, the correlation between the basic absorption frequency and the plasma surface wave resonance frequency can be obtained according to the pattern of the shape.
This step S21 corresponds to the process of (AB2) in the present invention.

[Step S22] When the correlation between the fundamental absorption frequency and the plasma surface wave resonance frequency is obtained, the plasma surface wave resonance frequency is proportional to the electron density squared. The correlation can also be obtained. This correlation is stored in the correlation memory 27 for each probe shape. This step S22 corresponds to the step (AB3) in the present invention. Further, the flow from step S20 to step S22, that is, the flow of obtaining the correlation stored in the correlation memory 27 corresponds to the storage process of (ab1) in the present invention.

In the plasma processing according to the above steps, the plasma processing apparatus according to the second embodiment has the following effects.

In steps S20 to S22, the correlation memory 2 determines the correlation between the fundamental absorption frequency and the electron density for each shape of the measuring probe 5.
Store in advance in 7. The result of the fundamental absorption frequency measured in step S7a is sent to the electron density conversion unit 21, and the electron density is obtained based on the correlation read from the correlation memory 27. As a result, since the above correlation is stored in advance according to the shape of the probe, it is possible to immediately measure the electron density, which is the plasma density information, only by measuring the fundamental absorption frequency. as a result,
It is possible to easily grasp the electron density and the like as compared with the related art.

As in the first embodiment, a current-driven PLL is used as the measurement power source 6 using the heterodyne system.
Or it is not necessary to configure the measurement probe 5 so that the outer diameter φ of the tube 13, the length L of the antenna, and the length d from the tip to the connection are approximately equal, but the mixing of noise is reduced. In order to reduce the time required for setup or to easily grasp the plasma density information, it is preferable to use the above-mentioned one or configure the measuring probe 5 as described above.

[Third Embodiment] Next, a third embodiment of the present invention will be described. FIG. 10 is a block diagram showing a schematic configuration of the plasma processing apparatus according to the third embodiment. The same parts as those of the first and second embodiments are designated by the same reference numerals, and the illustration and description of the parts will be omitted.

The plasma processing apparatus according to the first embodiment is provided with the first output device 20, whereas the plasma processing apparatus according to the third embodiment is provided with the second output device 28.
The second output device 28 includes an electron density conversion unit 21, an electron density memory 29, and a display monitor 30 in addition to the absorption frequency derivation unit 20a and the harmonic removal unit 20b as in the first embodiment. It is configured. The electron density converter 21 and the display monitor 30 according to the third embodiment are the same as the electron density converter 21 and the display monitor 20c according to the first and second embodiments, respectively. The second output device corresponds to the second output means of the present invention.

The electron density memory 29 has a function of storing the result of the electron density sequentially sent to the electron density 21 from the absorption frequency deriving unit 20a for each time. The electronic density memory 29 is a recording medium including a ROM and the like.

The display monitor 30 has a function of outputting the result of the electron density for each time. As the output result, for example, as shown in FIG. 11, the time axis is set as the horizontal axis and the electron density is set as the vertical axis for output display on the display monitor 30. In the case of FIG. 11, which is the case of the plasma etching process, the time when the electron density fluctuates is used as the end point detection (end point) by utilizing the fact that the electron density fluctuates at the end of etching. Although the display monitor 30 is also used as the display monitor 20a according to the first embodiment in the third embodiment, it may be separately provided.

Next, the flow of plasma processing in the plasma processing apparatus according to the third embodiment having the above-mentioned configuration will be described with reference to the flowchart of FIG. Figure 1
Regarding the flowchart of No. 2, steps S1 to S in the flowcharts according to the first and second embodiments are performed.
The description up to 7 is omitted because it is the same. At the same time when the electron density is measured, a timer (not shown) is reset, and the timer starts counting. Also,
Set the time you want to display in advance.

[Step S8b] When the fundamental absorption frequency is derived by the absorption frequency deriving unit 20a, it is sent to the electron density converting unit 21 and stored in the electron density memory 29. The timer data counted at this time is also stored in the electron density memory 29 as time data, and the electron density result is stored corresponding to time.

[Step S9b] For example, as shown in FIG. 11, time is plotted on the horizontal axis and electron density is plotted on the vertical axis, and the result of the electron density at the measured time is associated with the time axis and the electron density axis. It is attached and plotted, and is output and displayed on the display monitor 30.

[Step S10b] If the preset time has not come as described above, it is determined that the measurement time has not ended, and the process returns to step S1 to measure the electron density. If the set time has elapsed, it is considered that the measurement time has elapsed, and the process ends. The steps S9b to S10b correspond to the step (c) in the present invention.

As described above, in the steps from step S9b to step S10b, the electron density is repeatedly performed a plurality of times, and the result of the electron density is output and displayed every hour, so that the plasma density information is obtained for each time series. The electron density etc. can be grasped.

Further, in the third embodiment, the vertical axis represents the electron density, but not only the electron density but also the absorption frequency may be displayed in the vertical axis for output display.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described. FIG. 13 is a block diagram showing a schematic configuration of the plasma processing apparatus according to the fourth embodiment. The first
Portions common to those of the apparatus of the third embodiment are designated by the same reference numerals, and illustration and description of those portions will be omitted.

In the plasma processing apparatus according to the fourth embodiment,
As in the third embodiment, the second output device 28 is provided.
The second output device 28 includes an absorption frequency derivation unit 20a, a harmonic wave removal unit 20b, an electron density conversion unit 21, an electron density memory 29, and a display monitor 30 as in the third embodiment, and also derives an integrated value. It is composed of a section 31. The integrated value deriving unit 31 has a function of integrating the values of the electron density at each time stored in the electron density memory 29 with respect to time and deriving the time integration of the electron density. The integrated value deriving unit 31 corresponds to the integrated value deriving means in the present invention. Further, the integrated value derivation unit 31 is composed of a recording medium composed of a ROM or the like.

Further, in the first embodiment, the generation power control unit 4
Has an electron density setting unit 11, but has an integrated value comparing unit 32 in the fourth embodiment. The integrated value comparison unit 32
The integrated value obtained by the integrated value deriving unit 31 is compared with the set integrated value, and the (former) integrated value found by the integrated value deriving unit 31 reaches the set (latter) integrated value. If not, the plasma processing is continued, and if the former integrated value has reached the latter integrated value, the impedance matching device 12 is operated to stop the supply of power for generation, and the plasma processing is terminated. Has been done.

More specifically, referring to FIG. 11, the time is divided for each ΔT, and the electron density at that time is obtained for each ΔT. When ΔT is sufficiently small, a value obtained by multiplying ΔT by the electron density, that is, the area of the shaded area in FIG. 11 is obtained as the time integration of the electron density. When the plasma treatment is plasma etching, the film thickness to be etched is
The deposited film thickness has a correlation with the above-mentioned integrated value. Hereinafter, plasma etching will be described as an example.

In plasma processing represented by normal etching, there is a correlation between the electron density and the processing speed (etching rate). For example, if the electron density is high, the processing speed is high, and if the electron density is low, the processing speed is low. The processing time can be controlled by measuring this correlation in advance and controlling the electron density. Conversely, even if the electron density of the generated plasma PM cannot be controlled, stable plasma processing can be realized by controlling the processing time, and in the case of etching, a certain film thickness can be etched. be able to.

When the electron density is unstable during plasma processing and the processing speed is not constant, during processing, continuous,
Alternatively, the electron density can be measured intermittently, the values can be integrated over time, and the plasma processing can be controlled based on the integrated value as described above. On the other hand, when the electron density is stable during the plasma processing and the processing speed is constant, it is sufficient to measure the electron density immediately before or after the processing is started. According to the electron density measured at this time, a timer (not shown) is set for a preset time (processing target time) as in the third embodiment, the timer starts counting, and processing is performed up to the processing target time. do it. Further, when the target time is reached, the plasma processing can be controlled with even higher accuracy by comparing whether the electron density is the same as the electron density immediately before or immediately after the processing is started.

Next, the flow of plasma processing in the plasma processing apparatus according to the fourth embodiment having the above-mentioned structure will be described with reference to the flowchart of FIG. Figure 1
Regarding the flowchart of No. 4, steps S1 to S in the flowcharts according to the first to third embodiments
The description up to 7 is omitted because it is the same. Further, the integrated value corresponding to the plasma processing is set in advance.

[Step S8c] When the fundamental absorption frequency is derived by the absorption frequency deriving unit 20a, it is sent to the electron density converting unit 21 and stored in the electron density memory 29. The timer data counted at this time is also stored in the electron density memory 29 as time data, and the electron density result is stored corresponding to time. This step S8c corresponds to the step (d) in the present invention.

[Step S9c] The electron density value at each time stored in the electron density memory 29 is sequentially sent to the integrated value deriving section 30 to derive the time integration of the electron density as shown in FIG. The derived integrated value is sent to the integrated value comparison unit 32. Further, the result (integrated value) may be output and displayed on the display monitor 30 as needed. This step S9c corresponds to the step (e) in the present invention.

[Step S10c] If the integrated value obtained as described above has not reached the set integrated value, it is determined that the plasma processing has not ended, and the process returns to step S1 to continue the plasma processing. If the set integrated value has been reached, it is considered that the plasma processing has been completed, the impedance matching device 12 is operated to stop the supply of power for generation, and the plasma processing is terminated.

In the fourth embodiment, the plasma processing is terminated when the set integrated value is reached, but when the plurality of substrates W are processed, the set integrated value is reached. Then, the substrate W being processed is taken out from the chamber 1,
The substrate W to be processed next may be housed in the chamber 1 and controlled to perform plasma processing.

As described above, by repeating the electron density a plurality of times and integrating the electron density values with respect to time, the time integrated electron density can be grasped, and the time integrated electron density, That is, the plasma processing can be easily performed by the integrated value comparison unit 32 in the generation power control unit 4 based on the integrated value.

The present invention is not limited to the above embodiment, but can be modified as follows.

(1) In the above-described second embodiment, the correlation memory 27 stores the correlation by measuring the fundamental absorption frequency and the plasma surface wave resonance frequency.
The method for obtaining the correlation is not limited to the second embodiment as long as it is a means for storing the correlation between the basic absorption frequency and the plasma density information represented by the electron density. For example, the method of obtaining the correlation by the geometric analysis method (H. Kokura et al., Jpn.J.Appl.Phys., 38, (1999) 52
62.) or a method of obtaining a correlation by the finite difference time domain method (also called FDTD method) (N. Toyoda et al,
Proc. Of PSS-2001 / SPP-18 (2001) 125.) Etc.

Although the description of the geometric analysis method is omitted, a method of obtaining the correlation by the geometric analysis method will be briefly described. The measurement probe 5 is modeled as a concentric three-layer cylinder model laminated on air, a dielectric (eg, quartz), and plasma. Then, analysis is performed using electrostatic approximation. When the frequency is analyzed by the geometric analysis method while changing the length in the longitudinal direction of the concentric three-layer cylinder model, a graph depending on the length in the longitudinal direction is obtained (not shown). This length is the length L of the antenna of the measurement probe 5.
Or the length d from the tip to the connection. Therefore, the frequency that converges when the length approaches 0 is regarded as the plasma surface wave resonance frequency as described in the second embodiment. After that, the correlation between the fundamental absorption frequency and the electron density is obtained and stored in the same procedure as in the second embodiment.

The description of the finite difference time domain method (FDTD method) is also omitted, but a method of obtaining the correlation by the finite difference time domain method will be briefly described. Air, a dielectric (eg, quartz), which constitutes the measurement probe 5,
The plasma and antenna are made into a grid by spatial coordinates, that is, meshed, and the time-dependent change of each electromagnetic field at each grid point is obtained by the finite difference time domain method. Then, the fundamental absorption frequency is obtained by obtaining the reflectance of the electromagnetic field. After that, in the same procedure as in the second embodiment,
The correlation between the fundamental absorption frequency and the electron density is obtained and stored.

[0186]

As is apparent from the above description, according to the present invention, a heterodyne system (the invention described in claims 1, 10 and 21) or a current driven low pass filter (claims 3, 12 and 19). By using the invention described in 23), it is possible to easily grasp the plasma density information by reducing the time required for mixing in noise or setting up the measurement power supply. Further, the correlation between the basic absorption frequency and the plasma density information is used (the invention according to claims 4, 13, and 24), or the plasma density information is measured a plurality of times, and each measurement result of the plasma density information is timed. Output with time (invention according to claims 8, 17, and 28) or plasma density information is measured a plurality of times, each measurement result of the plasma density information is obtained with respect to time, and the value of the plasma density information at each time Is integrated with respect to time to derive the time integration of plasma density information (the invention according to claims 9, 18, and 29), or the outer diameter of the dielectric region, the length of the antenna, and the antenna and the cable. The plasma density information measuring probe is configured such that the lengths from the connection portion to the tip of the dielectric region are substantially equal (claim 19). By Akira),
Immediately measure the plasma density information by simply measuring the basic absorption frequency, or grasp the plasma density information for each time series, or grasp the time-integrated plasma density information, or easily identify the fundamental absorption frequency. be able to. As described above, since the plasma density information can be easily grasped, the plasma characteristics can be grasped.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment device.

FIG. 2 is a partial vertical cross-sectional view showing the configuration of the measurement probe according to the first to third embodiments.

FIG. 3 is a block diagram showing a configuration of an oscillation closed circuit (PLL) according to the first example.

FIG. 4 is a flowchart showing a flow of plasma processing according to the first embodiment.

FIG. 5A is a waveform diagram showing a change in reflectance with respect to frequency of the measurement power output when noise is superimposed, and FIG. 5B does not output for frequencies at harmonics. It is a wave form diagram which shows the change with respect to the frequency of the reflectance of the measurement electric power at this time.

FIG. 6 is a graph provided for explaining an absorption frequency.

FIG. 7 is a block diagram showing a configuration of a second embodiment device.

FIG. 8 is a flowchart showing a flow of plasma processing according to the second embodiment.

FIG. 9 is a flowchart showing a flow until obtaining a correlation between a fundamental absorption frequency and an electron density.

FIG. 10 is a block diagram showing a configuration of a device of a third embodiment.

FIG. 11 is a graph showing changes with time in electron density from the time plasma is generated to the time plasma processing is completed.

FIG. 12 is a flowchart showing the flow of plasma processing according to the third embodiment.

FIG. 13 is a block diagram showing the configuration of a fourth example device.

FIG. 14 is a flowchart showing the flow of plasma processing according to the fourth embodiment.

FIG. 15 is a diagram for explaining a conventional method for measuring plasma density information.

FIG. 16 is a block diagram showing a configuration of a conventional oscillation closed circuit (PLL).

[Explanation of symbols]

4 ... Generation power control unit 5… Measuring probe 6… Power supply for measurement 13… Tube 17… Frequency output section 18… DBM (Double Balanced Mixer) 19 ... BPF (band pass filter) 20 ... First output device 20a ... Absorption frequency derivation unit 20b ... Harmonic elimination section 21 ... Electron density converter 23 ... Amplifier 24 ... LPF (low pass filter) L ... Antenna length d ... Length from the tip to the connection φ ... outer diameter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/31 H01L 21/302 E (72) Inventor Takashi Fujitate 10-7 Kameicho, Takarazuka-shi, Hyogo Stock Company Nissin (72) Inventor Katshiko Sasakawa 10-7 Kamei-cho, Takarazuka-shi, Hyogo Nissin Co., Ltd. (72) Inventor Akihiro Yanase 10-7 Kamei-cho, Takarazuka-shi, Hyogo Nisshin Co., Ltd. F-term (reference) 4G075 AA30 AA42 AA61 BA02 BC04 BC06 BD14 CA25 CA47 DA02 EB01 EB41 EC21 FB04 FB06 FB12 FC15 4K030 FA03 JA00 JA11 JA16 JA18 JA19 KA30 5F004 AA16 CB06 5F045 AA08 GB08

Claims (29)

[Claims] 1. A plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a)
A step of supplying plasma density information measuring power to the plasma from a plasma density information measuring power source for measuring the plasma density information; and (b) using the plasma density information measuring probe, the plasma density information depending on a plasma load. And a step of measuring plasma density information based on reflection or absorption of measuring power, wherein the step (a) comprises:
A step of outputting electric power for measuring plasma density information while sweeping the frequency from the power source for measuring plasma density information, and supplying the electric power for measuring plasma density information to the plasma for each frequency. Is the addition or subtraction of a predetermined frequency to each output frequency, which is each frequency swept from the power supply for measuring plasma density information, and each addition that is each frequency obtained by the addition or subtraction. / Output the subtraction frequency,
Of the respective frequencies obtained by subtracting the respective addition / subtraction frequencies from the respective reflection frequencies, which are the respective frequencies of the plasma density information measuring power reflected or absorbed by the plasma load, and the latter subtraction. The method for measuring plasma density information is characterized in that it is a process of measuring plasma density information by passing only a frequency corresponding to the value of the predetermined frequency to obtain reflection or absorption of power for measuring plasma density information. 2. The plasma density information measuring method according to claim 1, wherein the step (b) relates to the plasma generation power output from the plasma generation power source for generating plasma. A method for measuring plasma density information, which is a process of removing the frequency component and outputting the reflected or absorbed electric power for measuring plasma density information when the frequency coincides with a harmonic. 3. A plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a)
A step of supplying plasma density information measuring power to the plasma from a plasma density information measuring power source for measuring the plasma density information; and (b) using the plasma density information measuring probe, the plasma density information depending on a plasma load. And a step of measuring plasma density information based on reflection or absorption of measuring power, wherein the step (a) comprises:
In the process of outputting the plasma density information measuring power while sweeping the frequency from the plasma density information measuring power source, and supplying the plasma density information measuring power to the plasma for each frequency, the plasma density information measuring power The plasma density information measuring method, wherein the power supply is an oscillation closed circuit controlled by a phase difference signal, and a low pass filter in the oscillation closed circuit is driven by a current. 4. A plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a)
A step of supplying plasma density information measuring power to the plasma from a plasma density information measuring power source for measuring the plasma density information; and (b) using the plasma density information measuring probe, the plasma density information depending on a plasma load. And a step of measuring plasma density information based on reflection or absorption of measuring power, wherein the steps (a) and (b) are (ab1) a plurality of frequencies caused by reflection or absorption by a plasma load. Of the absorption frequency of the, the basic absorption frequency is the absorption frequency in the reflectance of the largest loss of power for measuring plasma density information due to reflection, and the correlation of the plasma density information in advance for each shape of the probe for measuring the plasma density information. Memorization process of storing and (ab2) Plasma density information measurement from the power source for measuring plasma density information Supplying power to the plasma, and the fundamental frequency measurement process of measuring the fundamental absorption frequency using a probe for measuring plasma density information, (ab3) wherein (a
a plasma density information measuring step of measuring plasma density information based on the fundamental absorption frequency measured in the fundamental frequency measuring step of b2) and the correlation stored in advance in the storing step of (ab1). A method for measuring plasma density information, characterized by: 5. The method for measuring plasma density information according to claim 4, wherein the storage process of (ab1) is (AB1).
1) The process of measuring the fundamental absorption frequency for each shape of the plasma density information measuring probe, and (AB2) measuring the plasma surface wave resonance frequency which is a constant frequency observed regardless of the shape of the plasma density information measuring probe. And (AB3) based on the steps (AB1) and (AB2), the correlation of plasma density information having a constant correlation with the fundamental absorption frequency and the plasma surface wave resonance frequency is obtained, A method of measuring plasma density information, which is a process of storing the correlation. 6. The plasma density information measuring method according to claim 4, wherein the storing process of (ab1) is (AB1).
4) Based on the geometrical analysis method in which the plasma density information measuring probe is modeled as a concentric three-layer cylindrical model in which air, a dielectric, and plasma are laminated from the center to the outside, and analysis is performed using electrostatic approximation. Then, the process of obtaining the fundamental absorption frequency for the length in the longitudinal direction of the concentric three-layer cylindrical model and (AB5) the frequency that converges when the length in the longitudinal direction of the concentric three-layer cylindrical model approaches 0 , The process of obtaining the plasma surface wave resonance frequency, (AB
6) Based on the processes of (AB4) and (AB5), the correlation of the plasma density information having a constant correlation with the fundamental absorption frequency and the plasma surface wave resonance frequency is obtained, and the correlation is stored. And a plasma density information measuring method. 7. The plasma density information measuring method according to claim 4, wherein the storing process of (ab1) is (AB1).
7) Frequency-dependent electromagnetic field based on the finite-difference time-domain method for obtaining the time change and the area change of the electromagnetic field by making the air, the dielectric, the plasma, and the antenna constituting the probe for measuring the plasma density information into lattices in spatial coordinates. Of the basic absorption frequency for each shape of the probe for measuring plasma density information by measuring the reflectance of the plasma density information, and (AB8) Plasma surface wave which is a constant frequency observed regardless of the shape of the probe for measuring plasma density information. Based on the process of obtaining the resonance frequency based on the finite difference time domain method and the process of (AB9) (AB7) and (AB8), there is a fixed correlation with the fundamental absorption frequency and the plasma surface wave resonance frequency. Plasma density, which is the process of obtaining the correlation of the plasma density information in the table and storing the correlation. Broadcast measurement method. 8. A plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a)
A step of supplying plasma density information measuring power to the plasma from a plasma density information measuring power source for measuring the plasma density information; and (b) using the plasma density information measuring probe, the plasma density information depending on a plasma load. A process of measuring plasma density information based on reflection or absorption of measurement power, and (c) the above (a) to (b)
And a step of repeatedly outputting each result of the plasma density information obtained in the step (b) over time, by repeating each of the steps up to a plurality of times. . 9. A plasma density information measuring method for measuring plasma density information indicating characteristics of plasma, comprising: (a)
A step of supplying plasma density information measuring power to the plasma from a plasma density information measuring power source for measuring the plasma density information; and (b) using the plasma density information measuring probe, the plasma density information depending on a plasma load. A process of measuring plasma density information based on reflection or absorption of measurement power, and (d) above (a) to (b)
Each of the above steps is repeated a plurality of times to obtain each result of the plasma density information obtained in the step (b) with respect to time, and (e) each step obtained in the step (d). And a step of deriving a value of the plasma density information in time with respect to time and deriving a time integration of the plasma density information. 10. A plasma density information measuring device for measuring plasma density information indicating characteristics of plasma, wherein plasma for supplying plasma density information measuring power to the plasma while sweeping a frequency for measuring the plasma density information. A density information measuring power source, a plasma density information measuring probe that measures plasma density information based on reflection or absorption of the plasma density information measuring power by a plasma load, and each swept from the plasma density information measuring power source To each output frequency, which is the frequency of, and a first frequency output means for outputting each addition / subtraction frequency which is each frequency obtained by adding or subtracting a predetermined frequency, and being reflected or absorbed by the plasma load. For each reflection frequency, which is each frequency of the plasma density information measurement power, A second frequency output means for subtracting and outputting each addition / subtraction frequency output from the first frequency output means, and each frequency obtained by the second frequency output means. To a frequency passing means for passing only a frequency corresponding to the value of the predetermined frequency, and a first output for outputting the electric power at the frequency passed by the frequency passing means as the reflected or absorbed electric power for measuring plasma density information. And a plasma density information measuring device. 11. The plasma density information measuring device according to claim 10, wherein the first output means relates to plasma generation power output from a plasma generation power supply for generating plasma. A plasma density information measuring device, comprising: a harmonic wave removing means for removing the frequency component when the frequency of the harmonic is matched and outputting the reflected or absorbed power for measuring the plasma density information. 12. A plasma density information measuring device for measuring plasma density information indicating characteristics of plasma, wherein the plasma is supplied with plasma density information measuring power while sweeping a frequency to measure the plasma density information. A power source for measuring density information, and a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the power for measuring plasma density information by a plasma load, and the power source for measuring plasma density information is a low power source. An oscillating closed circuit controlled by a phase difference signal, comprising a low pass filter for passing a frequency on the band side, and a current conversion means for converting a phase difference signal into a current for driving the low pass filter. A plasma density information measuring device characterized by being present. 13. A plasma density information measuring device for measuring plasma density information indicating characteristics of plasma, wherein the plasma is supplied with plasma density information measuring power while sweeping a frequency for measuring the plasma density information. A density information measuring power source, a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the plasma density information measuring power by the plasma load, and a frequency caused by reflection or absorption by the plasma load. Of the plurality of absorption frequencies, the basic absorption frequency, which is the absorption frequency at the reflectance with the largest loss of power for measuring plasma density information due to reflection, and the correlation of the plasma density information are shown for each shape of the plasma density information measuring probe. Is provided with a correlation storage means stored in advance. Measuring device for plasma density information. 14. The plasma density information measuring device according to claim 13, wherein the correlation storing means measures the basic absorption frequency for each shape of the plasma density information measuring probe, and The result obtained by measuring the plasma surface wave resonance frequency, which is a constant frequency observed regardless of the shape, is the plasma density information that has a constant correlation with the fundamental absorption frequency and the plasma surface wave resonance frequency. And a plasma density information measuring device. 15. The apparatus for measuring plasma density information according to claim 13, wherein the correlation storage means has the probe for measuring plasma density information laminated on air, a dielectric, and plasma from the center to the outside. Based on a geometric analysis method of modeling into a concentric three-layer cylindrical model and performing analysis using electrostatic approximation, the fundamental absorption frequencies are obtained for the lengths in the longitudinal direction of the concentric three-layer cylindrical model, and the concentric three-layer cylindrical model is obtained. The result obtained by finding the frequency that converges when the length of the cylindrical model in the longitudinal direction approaches 0 as the plasma surface wave resonance frequency is a constant with respect to the fundamental absorption frequency and the plasma surface wave resonance frequency. A plasma density information measuring device, characterized in that the plasma density information is correlated. 16. The plasma density information measuring device according to claim 13, wherein the correlation storing means comprises air, a dielectric, and the like which constitute the plasma density information measuring probe.
For each shape of the probe for measuring plasma density information, the frequency dependence of the electromagnetic field is calculated based on the finite-difference time-domain method in which the plasma and antenna are gridded in spatial coordinates and the time and area changes of the electromagnetic field are calculated. Along with the fundamental absorption frequency, the plasma surface wave resonance frequency, which is a constant frequency observed regardless of the shape of the probe for measuring plasma density information, is obtained based on the finite difference time domain method. A plasma density information measuring device, wherein the plasma density information has a certain correlation with a fundamental absorption frequency and the plasma surface wave resonance frequency. 17. A plasma density information measuring device for measuring plasma density information indicating characteristics of plasma, wherein the plasma is supplied with plasma density information measuring power while sweeping a frequency in order to measure the plasma density information. A power source for measuring density information, a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the plasma density information measuring power by a plasma load, and a plurality of times using the plasma density information measuring probe And a second output means for measuring the plasma density information over time and outputting each measurement result of the plasma density information over time. 18. A plasma density information measuring device for measuring plasma density information indicating characteristics of plasma, wherein the plasma is supplied with plasma density information measuring power while sweeping a frequency for measuring the plasma density information. A power source for measuring density information, a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the plasma density information measuring power by a plasma load, and a plurality of times using the plasma density information measuring probe An integrated value deriving means for measuring plasma density information over time, obtaining each measurement result of the plasma density information with respect to time, integrating values of the plasma density information at each time with respect to time, and deriving time integration of the plasma density information And a plasma density information measuring device. 19. Plasma density information for measuring plasma density information on the basis of reflection or absorption of plasma density information measuring power supplied to plasma from a plasma density information measuring power source for measuring plasma density information. A measurement probe, which has one linear antenna configured to radiate electric power, a cable for transmitting the electric power for measuring the plasma density information, and a dielectric region having a closed tip coupled to plasma. The cable and the antenna are covered with the dielectric region, and the outer diameter of the dielectric region, the length of the antenna, and the connecting portion between the antenna and the cable to the tip of the dielectric region are provided. A probe for measuring plasma density information, characterized in that the lengths thereof are substantially equal to each other. 20. A computer readable plasma density information measuring program recorded with a program for causing a computer to execute the plasma density information measuring method according to any one of claims 2 or 4. recoding media. 21. A plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein plasma density information measuring power is supplied to plasma while sweeping a frequency for measuring plasma density information. A power supply for measurement, a plasma density information measurement probe that measures plasma density information based on reflection or absorption of the power for measuring plasma density information due to a plasma load, and each frequency swept from the power supply for plasma density information measurement For each output frequency that is
First frequency output means for respectively outputting the subtracted frequencies, and respective reflection frequencies which are respective frequencies of the plasma density information measuring power reflected or absorbed by the plasma load, respectively from the first frequency output means. Second frequency output means for subtracting and outputting each of the output addition / subtraction frequencies, and only a frequency that matches the value of the predetermined frequency among the frequencies obtained by the second frequency output means Based on the measured plasma density information, and a first output means for outputting electric power at a frequency passed by the frequency passing means as reflected or absorbed electric power for measuring plasma density information, And a control means for controlling plasma processing. 22. The plasma processing apparatus according to claim 21, wherein the output frequency of the first output means is
When the frequency of the harmonics related to the plasma generation power output from the plasma generation power supply for generating plasma matches, the frequency component is removed and output as reflection or absorption of the plasma density information measurement power. A plasma processing apparatus comprising a harmonic wave removing means. 23. A plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein plasma density information measuring power is supplied to plasma while sweeping a frequency for measuring plasma density information. A measurement power source, a plasma density information measurement probe that measures plasma density information based on reflection or absorption of the plasma density information measurement power due to a plasma load, and plasma processing control based on the measured plasma density information The power source for measuring plasma density information includes a low-pass filter that passes a low-frequency band, and a current converter that converts a phase difference signal into a current for driving the low-pass filter. And a closed circuit controlled by a phase difference signal. Place 24. A plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein plasma density information is supplied to a plasma while sweeping a frequency to measure plasma density information. A measuring power source, a plasma density information measuring probe for measuring plasma density information based on reflection or absorption of the plasma density information measuring power by the plasma load, and a plurality of frequencies which are caused by reflection or absorption by the plasma load. Of the absorption frequency of the, the basic absorption frequency is the absorption frequency in the reflectance of the largest loss of power for measuring plasma density information due to reflection, and the correlation of the plasma density information in advance for each shape of the probe for measuring the plasma density information. The stored correlation storage means and the measured plasma density information. And a control means for controlling the plasma processing based on the information. 25. The plasma processing apparatus according to claim 24, wherein the correlation storage unit measures the basic absorption frequency for each shape of the plasma density information measuring probe and determines the shape of the plasma density information measuring probe. The result obtained by measuring the plasma surface wave resonance frequency, which is a constant frequency that is observed regardless of, is the correlation between the plasma absorption information and the fundamental absorption frequency, which has a constant correlation with the plasma surface wave resonance frequency. A plasma processing apparatus characterized by the following. 26. The plasma processing apparatus according to claim 24, wherein the correlation storing means sets the plasma density information measuring probe to air from the center toward the outside,
Based on a geometric analysis method in which a concentric three-layer cylindrical model laminated on a dielectric and plasma is modeled and analyzed using electrostatic approximation, the fundamental absorption frequency is calculated with respect to the longitudinal length of the concentric three-layer cylindrical model. The results obtained by finding the frequency that converges when the length of the concentric three-layer cylinder model in the longitudinal direction approaches 0 as the plasma surface wave resonance frequency are obtained as the fundamental absorption frequency and the plasma surface. A plasma processing apparatus, wherein the plasma density information has a constant correlation with the wave resonance frequency. 27. The plasma processing apparatus according to claim 24, wherein the correlation storing means grids the air, the dielectric, the plasma, and the antenna forming the probe for measuring the plasma density information in a spatial coordinate system to generate an electromagnetic field. Based on the finite-difference time-domain method for determining the time variation and the area variation of the plasma density information, the basic absorption frequency is obtained for each shape of the probe for measuring the plasma density information by measuring the reflectance of the frequency-dependent electromagnetic field Plasma surface wave resonance frequency, which is a constant frequency observed regardless of the shape of the probe, the result obtained by obtaining based on the finite difference time domain method, for the fundamental absorption frequency and the plasma surface wave resonance frequency A plasma processing apparatus, wherein the plasma density information is correlated with a certain correlation. 28. A plasma processing apparatus for performing plasma processing on an object to be processed in plasma, wherein plasma density information is supplied to a plasma while sweeping a frequency to measure plasma density information. A measurement power source, a plasma density information measurement probe that measures plasma density information based on reflection or absorption of the plasma density information measurement power due to a plasma load, and a plasma using the plasma density information measurement probe multiple times. Second density means for measuring the density information and outputting each measurement result of the plasma density information over time, and control means for controlling plasma processing based on the measured plasma density information. A plasma processing apparatus characterized by the above. 29. A plasma processing apparatus for performing plasma processing on an object to be processed in plasma, the plasma density information supplying electric power for measuring plasma density information to plasma while sweeping a frequency for measuring the plasma density information. A measurement power source, a plasma density information measurement probe that measures plasma density information based on reflection or absorption of the plasma density information measurement power due to a plasma load, and a plasma using the plasma density information measurement probe multiple times. The density information is measured, each measurement result of the plasma density information is obtained with respect to time, the value of the plasma density information at each time is integrated with respect to time, and an integrated value deriving means for deriving the time integration of the plasma density information, A control means for controlling the plasma processing based on the derived integrated value. A plasma processing apparatus characterized by the above.