JPH11330054A - Plasma processing method, plasma processor, plasma processing monitoring device and controller thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately detect a termination time position in a plasma processing and to stably and highly precisely plasma-process a processed object. SOLUTION: A light of a specified wavelength in plasma 4 is photoelectrically converted by an element 11, and is detected as a light-emitting wavelength which is synchronized with plasma excitation by an A/D converter 18 and the like, while a processed object 7 is plasma-processed in a processing chamber 1. A termination determining unit 15 monitors the progress situation of a plasma processing based on the timewise change of the light emitting waveform, and the plasma processing on the processed object 7 is finishingly controlled by the change of the light-emitting waveform to a specified waveform state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring the progress of a plasma process based on a temporal change of a light emission waveform synchronized with plasma excitation of light of a specific wavelength from an active species in a plasma and identifying the emission waveform. The plasma processing method and apparatus in which the plasma processing on the processing object is terminated by the change to the waveform state, and further, the plasma processing apparatus main body in which the processing target is subjected to plasma processing in the plasma processing chamber. On the other hand, the present invention relates to a plasma processing monitoring apparatus and a plasma processing monitoring control apparatus which are detachably added so as to constantly monitor and monitor the progress of the plasma processing.

[0002]

2. Description of the Related Art Plasma processing is widely applied to an etching apparatus, a semiconductor manufacturing process, a substrate manufacturing process for a liquid crystal display device, and the like. FIG. 13 shows an example of a conventional plasma etching apparatus. Show. As shown in the drawing, in this etching apparatus, a high voltage from a high-frequency power source 6 is applied to an upper electrode 2 disposed in parallel in the processing chamber 1.
The plasma 4 is generated from the etching gas by the discharge between the electrodes 2 and 3 when the voltage is applied between the lower electrodes 3, and the semiconductor wafer 7 as the object to be processed is etched by the active species. It has been done. During the etching process, the progress of the etching process is monitored, and the etching process is terminated more accurately by detecting the process end point, so that a desired pattern shape is formed on the semiconductor wafer 7 as a desired depth. It has been formed.

Incidentally, as a method of detecting the end point of the etching process, there have been known methods such as spectroscopic analysis and mass spectrometry.
As disclosed in Japanese Patent No. 321094, the fact is that the configuration for end point detection is simplified, and high-sensitivity spectral analysis is widely adopted as an end point detection method. Specifically, in the end point detection method, a specific active species is selected from active species such as radicals or ions such as an etching gas, a decomposition product thereof, or a reaction product, and an emission spectrum of the active species is selected. The strength has been measured.

Here, the plasma etching apparatus according to the prior art will be described in detail. As shown in FIG. 13, plasma emission from the plasma 4 during the etching process is transmitted through a quartz window 5 to an optical system such as an imaging lens. An image is formed on the incident end face of the optical fiber 9 by the system 8, and further, the light is incident on a spectroscope (monochromator or the like) 10 via the optical fiber 9. The spectroscope 10 can selectively extract only the wavelength component of the specific emission spectrum of the active species. After the extracted emission spectrum is detected as an emission intensity signal from the photoelectric conversion element 11, it is converted into digital data by an A / D converter 14 via an analog transmission line 12, and is processed in a predetermined manner by an end point determination unit 15. Is what it is. More specifically, the end point determination unit 15 performs a smoothing process and the like, and monitors the detected light emission intensity waveform 501 as a time change, as shown in FIG. By comparing the light emission intensity at the time when the light emission intensity waveform 501 changes greatly, its first derivative, the second derivative, or the like with a preset threshold value S, the end point time position E in the etching process is determined. In this case, the application of the high voltage from the high-frequency power supply 6 to the space between the electrodes 2 and 3 via the control signal line 16 is stopped.

Incidentally, the wavelength component of the specific emission spectrum selected by the spectroscope 10 will be additionally described. The wavelength component depends on the type of the etching gas or the object to be processed.
It is appropriately selected from the wavelength components of the plurality of emission spectra. For example, assuming that a silicon oxide film is etched using a fluorocarbon-based etching gas such as CF, in this case, an emission spectrum from CO as a reaction product (having a wavelength of 219 nm or 483.5 nm) is used. Etc.) or emission spectrum from CF as an intermediate product (wavelength 260 nm
Etc.) are to be selected.

[0006]

However, according to the above-mentioned prior art, even if the end point time position in the etching process is detected by simplifying the structure, the etching is performed with the miniaturization of the semiconductor circuit pattern. At present, the end point time position can no longer be accurately detected as a result of a decrease in the total area of the power portion and a decrease in the absolute amount of the reaction product. This is shown in FIG.
As shown in FIG. 4 as a light emission intensity waveform (indicated by a dotted line) 502, in addition to a decrease in the light emission intensity itself, a change in the light emission intensity before and after the end point time position is greatly reduced. This is because it is not easy to detect. In particular, when fluctuations occur in the entire plasma emission or when a signal causes a drift due to disturbance, it is almost impossible to detect the end point time position. In addition, the emission of active species in the plasma should be obtained as an emission waveform synchronized with the excitation of the plasma, but so far, the photoelectric conversion element and the signal processing system have a narrower band than the plasma excitation frequency. Due to the low-speed processing detection, the light emission waveform is exclusively detected as a smoothed DC component, and as a result, a light emission component that is included in the light emission waveform and that is unrelated to the etching reaction is also detected at the same time. This is S / N
This is one of the causes of the decline.

A first object of the present invention is to eliminate the influence of light-emitting components irrelevant to the etching reaction, and to reduce the influence of disturbances (plasma fluctuation, signal drift, etc.)
An object of the present invention is to provide a plasma processing method in which a target object can be plasma-processed stably and with high precision. A second object of the present invention is to simplify the structure, eliminate the influence of light-emitting components unrelated to the etching reaction, and reduce the effects of disturbances (plasma fluctuations, signal drifts, etc.) and stabilize the object to be processed. Another object of the present invention is to provide a plasma processing apparatus capable of performing plasma processing with high accuracy. A third object of the present invention is to constantly monitor the progress of the plasma processing performed in the plasma processing apparatus main body while the plasma processing apparatus main body is detachably attached to the plasma processing apparatus main body. Is to provide a plasma processing monitoring device capable of monitoring the plasma processing with high accuracy. A fourth object of the present invention is to continuously monitor and control the progress of the plasma processing performed in the plasma processing apparatus main body while the plasma processing apparatus is detachably attached to the plasma processing apparatus main body. An object of the present invention is to provide a plasma processing monitoring control device capable of monitoring and controlling the situation with high accuracy.

[0008]

A first object of the present invention is basically to provide a plasma processing apparatus in which an object to be processed is subjected to plasma processing, and an emission intensity of a specific wavelength light from active species in plasma is converted into an emission intensity signal by photoelectric conversion. In the state where the light emission is detected, a light emission waveform synchronized with the plasma excitation is detected from the light emission intensity signal, and while the progress of the plasma processing is monitored based on the time change of the light emission waveform, the light emission waveform is in a specific waveform state. Is achieved by terminating the plasma processing for the object to be processed.

The second object is basically to provide an optical system for selectively detecting only a specific wavelength light from an active species in plasma outside a plasma processing chamber with respect to a plasma processing apparatus main body; Photoelectric conversion means for converting a specific wavelength light detected from the system into an emission intensity signal; and an A / D converter for A / D converting the emission intensity signal from the photoelectric conversion means in order to detect the emission intensity signal as an emission waveform synchronized with plasma excitation. Conversion means;
While monitoring the progress of the plasma processing based on the time change of the light emission waveform synchronized with the plasma excitation from the / D conversion means, the plasma processing for the object to be processed is terminated when the light emission waveform changes to a specific waveform state. This is achieved by integrally providing a plasma processing monitoring control means for controlling as much as possible.

The third object is basically to provide an optical system for selectively detecting only a specific wavelength light from an active species in plasma outside a plasma processing chamber, and a detection specific wavelength light from the optical system. A / D conversion means for converting the light emission intensity signal from the photoelectric conversion means into a light emission waveform synchronized with the plasma excitation, This is at least achieved by a plasma processing monitoring means for monitoring the progress of the plasma processing based on a time change of a light emission waveform synchronized with the plasma excitation from the D conversion means.

The fourth object is basically to provide an optical system for selectively detecting only a specific wavelength light from an active species in a plasma outside a plasma processing chamber, and a detection specific wavelength light from the optical system. A / D conversion means for converting the light emission intensity signal from the photoelectric conversion means into a light emission waveform synchronized with the plasma excitation, While monitoring the progress of the plasma processing based on the time change of the light emission waveform synchronized with the plasma excitation from the D conversion means, the plasma processing for the object to be processed is terminated when the light emission waveform changes to a specific waveform state. This is achieved by at least comprising a plasma processing monitoring and controlling means for controlling as much as possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 12, taking a plasma etching apparatus as an example. First, if the plasma processing apparatus according to the present invention in the first embodiment is described as a plasma etching apparatus,
FIG. 1 shows the overall configuration. As shown, the apparatus according to the present embodiment is a parallel plate type plasma etching apparatus, and a high frequency voltage from a high frequency power supply 6 is
By being applied between the upper electrode 2 and the lower electrode 3 arranged in parallel in the processing chamber 1, the electrodes 2, 3
The plasma 4 is generated from the etching gas by the discharge between the electrodes, and the semiconductor wafer 7 as the object to be processed is etched by the active species.
During the etching process, the plasma emission from the plasma 4 during the etching process is transmitted through the quartz window 5 by the optical system 8 such as an imaging lens so that the progress of the process is constantly monitored and controlled. After that, the light is further incident on a spectroscope (monochromator, interference filter, etc.) 10 through the optical fiber 9. The spectroscope 10 can selectively extract only the wavelength component of the specific emission spectrum of the active species. After that, the emission spectrum extracted by the spectroscope 10 is detected as an emission intensity signal from the photoelectric conversion element 11.
When a signal having a band equal to or higher than the power supply frequency is used, the emission intensity signal from the photoelectric conversion element 11 is obtained as a waveform as shown in FIG. As shown in the figure, when the cycle of the power supply frequency of the high-frequency power supply 6 is T, it can be seen that a light emission waveform 100 synchronized with this is obtained. On the other hand, in the reference signal generator 17, the excitation frequency of the plasma 4 (same as the power supply frequency of the high-frequency power supply 6) is detected as a reference signal by inductive coupling, and this is input to the A / D converter 18 as a sampling signal. It has become something. Here, A in the A / D converter 18
The / D conversion operation will be described in detail as follows.

That is, since the power supply frequency of the high-frequency power supply 6 generally ranges from several hundred kHz to several tens MHz,
In order to A / D convert the light emission waveform 100 as it is and obtain the light emission waveform 100 in a state with good reproducibility, the sampling frequency is set to several GHz and the A / D conversion is performed.
Although the conversion needs to be performed, it is clear that such A / D conversion is not practical given the upper limit A / D conversion speed of the current A / D converter in general. Therefore, the reference signal from the reference signal generator 17 is not used directly as the sampling frequency, but a value obtained by multiplying the frequency by N / (N + 1) is used as the sampling frequency for the A / D converter 18. If the sampling frequency is set as such, FIG.
As shown as 1, 102, 103,..., The light emission waveform 100 is sampled with a slightly different phase every one cycle (such a sampling method is called undersampling). Therefore, as shown as the detection waveform 200 in FIG. 3, the emission waveform 100 for one cycle can be detected for the first time by sampling N times. At this time, if N is set as a sufficiently large value, for example, 100 or more, the emission waveform 100 can be accurately reproduced. If the power supply frequency of the high-frequency power supply 6 is unstable at this time, the sampling is performed N times more than once and the average value is used as the detection waveform 200 to further stabilize. As a result, a detection waveform 200 is obtained.

As can be seen from the detection waveform 200 shown in FIG. 3, in the A / D converter 18, digital waveform data is sequentially detected in the analog light emission waveform 100. Is transmitted to the end point determination unit 15 via the digital transmission line 12b, and is processed as a detection waveform 200 in a predetermined manner. Here, the processing in the end point determination unit 15 will be described below with reference to FIGS. 4 (A) and 4 (B).

That is, FIGS. 4A and 4B show a light emission waveform 601 of the specific wavelength light during the etching process and a light emission waveform 602 of the specific wavelength light after the end of the etching process (end point time position), respectively. Although both are obtained as waveforms synchronized with the plasma excitation period T by the high-frequency power supply 6, a remarkable change before and after the end of the etching process is observed as a large change in amplitude at a specific phase. It has become something. This makes it possible to determine whether or not the end point time position has been reached, for example, by comparing the peak value Is during the etching process on the emission intensity depending on the etching reaction with the preset peak value Ie (known). It is. If it is determined that the end point time position has been reached, the end point determination unit 15 sends a control signal line 16
Is notified to the etcher main body via the above, and the application of the high-frequency voltage from the high-frequency power supply 6 is stopped, thereby completing a series of etching processes. As can be seen from the above, the time change of the light emission waveform itself directly related to the etching reaction is captured, and the progress of the etching reaction is monitored as a state in which the influence of the light emitting component irrelevant to the etching reaction is excluded. Since the determination as to whether or not the position has been reached is made, the progress of the plasma processing is always stable in a state where the influence of disturbances such as miniaturization of the pattern to be processed, plasma fluctuation, signal drift, etc. has been reduced. In addition to the monitoring, the end of the plasma processing can be controlled with high accuracy as a result of the monitoring.

The first embodiment has been described above. Next, a second embodiment will be described with reference to FIGS. 5 to 7. FIG. 5 shows a plasma processing apparatus according to the second embodiment of the present invention. Is an overall configuration of a plasma etching apparatus. The processing in this embodiment is the same as that in the first embodiment up to the A / D conversion processing by the A / D converter 18. In this embodiment, the light emission lifetime of the active species is taken into consideration,
Of the present embodiment. As described above, the emission lifetime of the active species is considered.
When the A / D converter 18 detects the emission waveform of the emission spectrum of the active species in the same manner as in the first embodiment, if the power supply frequency of the high-frequency power supply 6 is several MHz.
If it becomes larger than the above, the period T of the power supply frequency and one period of the light emission waveform synchronized therewith also become about several hundred ns, and therefore, the light emission lifetime (several ns to several hundred n) of the active species.
This is because the influence of s) on the shape of the light emission waveform cannot be ignored. FIGS. 6A and 6B show light emission waveforms in such a state. As shown in FIG. 6A, the emission waveform 701 of the specific wavelength light during the etching process has a smaller overall amplitude than the emission waveform 601 described above.
Therefore, it is understood that the waveform component synchronized with the etching reaction does not appear as a visualized state. This is because the emission lifetime of the active species generated by the etching reaction becomes so long that it cannot be neglected compared to the cycle T of the plasma excitation frequency, and the attenuation of the emission of the active species is superimposed on the amplitude. Therefore, in order to detect only the component synchronized with the etching reaction from the light emission waveform 701, as shown in FIG. 5, the light emission waveform based on the light emission lifetime of the active species is provided by the waveform corrector 19 disposed before the end point determination unit 15. It is intended to correct the effect on the shape of the image. That is, the light emission waveform from the A / D converter 18 is observed as the light emission waveform 701 shown in FIG. 7A due to the influence of the light emission lifetime of the active species. If the deconvolution operation is performed between the above, a light emission waveform 801 after deconvolution shown in FIG. 7B in a state where the influence of the light emission lifetime is removed is obtained. Thereafter, the emission waveform 8 obtained by the waveform corrector 19
01 is the peak value I in the same manner as in the first embodiment.
s is detected and compared with a preset peak value, or only the waveform component region corresponding to the etching reaction near the peak value Is is subjected to the digital signal processing shown in FIG.
By being extracted as an etching reaction component waveform 901 shown in (C) and being transferred to the end point determination unit 15,
The end point determination unit 15 monitors the progress of the etching reaction and determines whether or not the end point time position has been reached. As in the case of the first embodiment, when it is determined that the end point time position has been reached, the application of the high-frequency voltage from the high-frequency power supply 6 is stopped by the end point determination unit 15, so that a series of etching processes is performed. It has been terminated.

Further, the third embodiment will be described. FIG. 8 shows the whole structure of the plasma processing apparatus according to the third embodiment of the present invention as a plasma etching apparatus. In the present embodiment, the device configuration is almost the same as that of the second embodiment, and the waveform corrector 19 removes the influence of the light emission lifetime. Is changed by the internal pressure of the processing chamber 1.
Plasma emission occurs when an atom or molecule excited to a high energy level transitions to a low energy level because the energy difference is emitted as light, but when the pressure in the processing chamber 1 is low ( (E.g., on the order of a few mTorr), the reduced rate of collision of the excited atom or molecule with another atom or molecule results in a longer effective emission lifetime of the excited atom or molecule. This is because the influence of the superposition due to the attenuation of the light emission increases. As shown in FIG. 9, for example, the emission waveform 300 in the case where the pressure in the processing chamber (inside) is high, the influence of the attenuation of the emission increases as shown in emission waveforms 301 and 302 as the pressure decreases. That is, the amplitude change in the light emission waveform is reduced. Generally attenuation rate of light emission time t, the tau _eff as the effective radiative lifetime, since expressed as exp (-t / τ _eff), decay rate curve in the case of changing the effective radiative lifetime tau _e f _f is , Are obtained as shown in FIG. As shown in FIG. 10, the shorter the effective light emission lifetime τ _eff, that is, the higher the pressure in the processing chamber, the larger the attenuation rate, and the more the effect of light emission attenuation converges accordingly. In consideration of such circumstances, an emission attenuation curve corresponding to the processing chamber pressure is prepared in advance, and the processing chamber pressure obtained via the processing chamber pressure data line 20 or when the plasma processing is performed. If the emission waveform is corrected by using the attenuation rate curve based on the pressure set in step (1), the influence of superposition due to attenuation of emission of active species can be removed with higher accuracy. FIG. 11 shows an example of a setting screen on the end point determination unit 15 in which such correction processing is considered. The user can directly set and input the emission lifetime, the high frequency power supply frequency (RF frequency), the chamber (processing chamber) pressure, or refer to another system for the emission waveform actually observed. It is set as a parameter for correction processing.

Finally, a fourth embodiment will be described with reference to FIG. As described above, in the spectroscope 10, only the wavelength component of the specific emission spectrum is selectively extracted. At this time, when the object to be processed contains H,
This is to actively extract the H emission spectrum (656.3 nm). For example, when a silicon oxide film is etched using a fluorocarbon-based etching gas such as CF, an emission spectrum (219 nm or 48 nm) from CO which is a reaction product thereof is obtained.
3.5 nm or the like, or an emission spectrum (260 nm or the like) from CF as an intermediate product is generally extracted and measured. However, when the object to be processed contains H,
Instead, the emission spectrum of H (656.3n
m) is to be selectively detected. this is,
This is because H has a shorter light emission lifetime than CO, CF, and the like, and is less affected by light emission attenuation. Further, in addition to the reason, the emission spectrum of H (656.3 nm) has a smaller decrease in the transmittance in the quartz window 5 due to the adhesion of the deposit than the ultraviolet region (400 nm or less), and therefore, the decrease in the detected light amount is smaller. Because.

This will be described in more detail with reference to FIG. 12. In the case where the deposit by the etching process is already attached to the quartz window 5, the quartz window 5 is not covered with the plasma processing time. It is known that the transmittance of light emission is reduced. FIG. 12 shows the rate of decrease in the transmittance as an example for each wavelength. As shown in the figure, comparing the transmittance curve 400 in the ultraviolet region with the transmittance curve 401 in the visible region (650 nm), the transmittance in the visible region has a smaller decrease rate than the ultraviolet region, and the plasma processing time It can be seen that the longer the is, the greater the difference in transmittance. Of the emission spectrum of active species CO, 48
A near 3.5 nm is used simultaneously with the etching gas.
Since the emission spectrum of r is strong and it is difficult to separate from the emission spectrum of CO, an ultraviolet region of 219 nm or 260 nm is used for detecting the emission spectrum of CO or CF. However, in the ultraviolet region, the amount of detected light is greatly reduced due to the influence of a decrease in the transmittance of the light emission detection window due to deposits. Therefore, the emission spectrum of H (656.3n
By selecting m), it is possible to reduce the influence of the attenuation of light emission and the effect of the decrease in the transmittance of the light emission detection window due to the deposits, thereby stably and accurately emitting light for a long time. A waveform can be detected. Incidentally, the selection of the emission spectrum of H and the detection of the end point time position of the plasma processing are not limited to the application of the plasma processing apparatus according to the present invention to general plasma processing apparatuses according to the present invention. It can be applied to end point time position detection.

Although the plasma processing method and the apparatus according to the present invention have been described above, in order to apply the plasma processing method according to the present invention to an existing plasma processing apparatus, it is necessary to monitor the progress of the plasma processing with respect to the existing plasma processing apparatus. The plasma processing monitoring device for plasma processing and the plasma processing monitoring control device for monitoring and controlling the progress of plasma processing may be detachably added to perform plasma processing. The plasma processing monitoring device and the plasma processing monitoring control device are components (optical system 8, spectroscope 10, photoelectric conversion element 1) other than the plasma processing device main body (high-frequency power supply 6 and processing chamber 1).
1, the reference signal generator 17, the A / D converter 18, and the end point determination unit 15).

In the above description, the etching apparatus is a parallel plate type plasma etching apparatus. However, the present invention is not limited to this. It is needless to say that the present invention can be applied to various etching apparatuses in which an etching reaction progresses periodically in synchronization with supply of some energy to a wafer, for example, a microwave etching apparatus. In the above embodiment, an example of application to an etching apparatus has been described. However, the present invention is also applicable to end point time position detection of various plasma processing apparatuses in which emission spectrum intensity changes as plasma processing progresses. . Further, the object to be processed is not limited to a semiconductor wafer, but can be applied to various elements and materials subjected to plasma processing in a manufacturing process thereof, such as a substrate for a liquid crystal display device. In any case, according to the present invention, it is possible to reduce defects caused by etching during the photolithography process, and it is possible to manufacture a high-quality semiconductor device. In addition, since it is possible to accurately detect the position of the end point of the etching process, it is possible to eliminate the need for a preceding operation for time management and improve the productivity of the etching process.
Automation of the entire semiconductor manufacturing line is also possible. Further, since the progress of the plasma processing can be monitored with high accuracy, it is possible to grasp variations in the film thickness of the object to be processed, for example, and to provide feedback to the pre-etching process. Therefore, productivity in the etching step can be further improved.

[0022]

As described above, in each of the first to seventh aspects, the influence of the light-emitting component irrelevant to the etching reaction is eliminated, and the influence of disturbance (plasma fluctuation, signal drift, etc.) is reduced. While the object to be processed is stable,
The plasma processing method capable of performing the plasma processing with high accuracy is also simplified according to claims 8 to 13, so that the structure is simplified to eliminate the influence of the light-emitting component irrelevant to the etching reaction, and furthermore, the disturbance (plasma fluctuation and signal fluctuation). A plasma processing apparatus capable of performing stable and high-precision plasma processing of an object to be processed while reducing the influence of drift or the like is further reduced. A plasma processing monitoring apparatus capable of monitoring the progress of plasma processing with high accuracy in a state where it is detachably attached to the plasma processing apparatus main body so as to constantly monitor the progress of the plasma processing apparatus. In
In order to constantly monitor and control the progress of the plasma processing performed in the plasma processing apparatus main body, it is possible to monitor and control the progress of the plasma processing with high accuracy while being detachably attached to the plasma processing apparatus main body. A plasma processing monitoring and control device is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a plasma processing apparatus according to a first embodiment of the present invention as a plasma etching apparatus;

FIG. 2 is a diagram for explaining a sampling method for an emission waveform of light of a specific wavelength.

FIG. 3 is a diagram for explaining how an emission waveform of light of a specific wavelength is A / D-converted by the sampling method;

FIGS. 4A and 4B are diagrams showing emission waveforms of light of a specific wavelength during the etching process and those after the etching process, respectively.

FIG. 5 is a diagram showing an overall configuration of a plasma processing apparatus according to a second embodiment of the present invention as a plasma etching apparatus;

FIGS. 6A and 6B are diagrams each showing a light emission waveform of light of a specific wavelength during an etching process, which is affected by a light emission lifetime, and a waveform after the etching process. FIG.

FIGS. 7A to 7C are diagrams for explaining the flow of processing on a light emission waveform until an etching reaction waveform component is extracted after removing the influence of the light emission lifetime;

FIG. 8 is a diagram showing an overall configuration of a plasma processing apparatus according to a third embodiment of the present invention as a plasma etching apparatus;

FIG. 9 is a diagram showing a change in a light emission waveform due to a difference in processing chamber pressure.

FIG. 10 is a diagram showing a change in a decay rate curve of light emission due to a difference in effective light emission lifetime.

FIG. 11 is a diagram illustrating an example of a setting screen on an end point determination unit in which light emission waveform correction processing based on light emission lifetime is considered.

FIG. 12 is a diagram illustrating, as an example, a rate of decrease in transmittance due to a difference in wavelength in a light emission detection window over time.

FIG. 13 is a diagram illustrating a configuration of an example of a plasma etching apparatus according to the related art.

FIG. 14 is a diagram for explaining a problem when an end point time position in an etching process is obtained from a simple change in emission intensity with time;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing room, 4 ... Plasma, 5 ... Quartz window, 6 ... High frequency power supply, 7 ... Semiconductor wafer, 8 ... Optical system, 10 ... Spectroscope, 1
1: photoelectric converter, 17: reference signal generator, 18: A / D
Converter, 15 ... End point judgment unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Tsunoda 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Hitachi, Ltd.

Claims (15)

[Claims] In a state in which an object to be processed is subjected to plasma processing and a light emission intensity of light of a specific wavelength from an active species in plasma is detected as a light emission intensity signal by photoelectric conversion, plasma excitation and plasma excitation are performed from the light emission intensity signal. After detecting the synchronized light emission waveform, the progress of the plasma processing is monitored based on the time change of the light emission waveform, and when the light emission waveform changes to the specific waveform state, the plasma processing for the object to be processed is terminated. Plasma processing method. 2. In a state where an object to be processed is subjected to plasma processing and the emission intensity of light of a specific wavelength from an active species in plasma is detected as an emission intensity signal by photoelectric conversion, plasma excitation and plasma excitation are performed from the emission intensity signal. After detecting the synchronized light emission waveform, the progress of the plasma processing is monitored based on the time change of the light emission waveform, and when the light emission waveform changes to the specific waveform state, the plasma processing for the object to be processed is terminated. In the above-described plasma processing method, after the emission intensity of light of a specific wavelength from an active species is detected as an emission intensity signal, A / D conversion is performed by undersampling to obtain sampling data over a plurality of plasma excitation periods. , A plasma processing method in which an emission waveform synchronized with plasma excitation is detected. 3. The method according to claim 1, wherein the light-emitting intensity of the specific wavelength light from the active species in the plasma is detected as a light-emitting intensity signal by photoelectric conversion while the object is being plasma-treated. After the emission waveform synchronized with the plasma excitation is corrected by the emission lifetime of the specific wavelength light, the emission waveform component synchronized with the plasma processing reaction is extracted, and the plasma is extracted based on the time change of the extracted emission waveform component. A plasma processing method, wherein the plasma processing on a target object is terminated when the emission waveform component changes to a specific waveform state while monitoring the progress of the processing. 4. The method according to claim 1, wherein the light-emitting intensity of the specific wavelength light from the active species in the plasma is detected as a light-emitting intensity signal by photoelectric conversion while the object is subjected to the plasma processing. After the emission waveform synchronized with the plasma excitation is corrected by deconvolution processing using the emission lifetime of the specific wavelength light as a parameter, the emission waveform component synchronized with the plasma processing reaction is extracted, and the extracted emission waveform is extracted. A plasma processing method in which the progress of the plasma processing is monitored based on the time change of the component, and the plasma processing for the object to be processed is terminated when the emission waveform component changes to a specific waveform state. 5. The method according to claim 1, wherein the light-emitting intensity of the specific wavelength light from the active species in the plasma is detected as a light-emitting intensity signal by photoelectric conversion while the object to be processed is subjected to plasma processing. After the emission waveform synchronized with the plasma excitation is corrected by the emission decay rate curve determined by the emission lifetime of the specific wavelength light, the emission waveform component synchronized with the plasma processing reaction is extracted, and the extracted emission is extracted. A plasma processing method in which the progress of plasma processing is monitored based on a time change of a waveform component, and the plasma processing on the object is terminated when the emission waveform component changes to a specific waveform state. 6. An emission intensity signal in a state where an emission intensity of light of a specific wavelength from an active species in plasma is detected as an emission intensity signal by photoelectric conversion while plasma processing is performed on an object to be processed in a plasma processing chamber. Detected from
The emission waveform synchronized with the plasma excitation is determined according to the pressure in the plasma processing chamber, and after being corrected by the deconvolution processing using the emission lifetime of the specific wavelength light as a parameter, the emission waveform component synchronized with the plasma processing reaction Is extracted, and while the progress of the plasma processing is monitored based on the time change of the extracted light emission waveform component, the light emission waveform component changes to a specific waveform state, and the plasma processing for the object to be processed is terminated. Plasma processing method. 7. In a state where an object to be processed is subjected to plasma processing and a light emission intensity of a specific wavelength light from active species in plasma is detected as a light emission intensity signal by photoelectric conversion, plasma excitation and plasma excitation are performed from the light emission intensity signal. After detecting the synchronized light emission waveform, the progress of the plasma processing is monitored based on the time change of the light emission waveform, and when the light emission waveform changes to the specific waveform state, the plasma processing for the object to be processed is terminated. The plasma processing method as described above, wherein the active species is hydrogen H, and the emission spectrum intensity of the hydrogen H is detected as an emission intensity signal. 8. A plasma processing apparatus in which an object to be processed is subjected to plasma processing in a plasma processing chamber, wherein the optical system selectively detects only light of a specific wavelength from active species in plasma outside the plasma processing chamber. System, photoelectric conversion means for converting light of a specific wavelength detected from the optical system into an emission intensity signal, and an A / D converter for detecting the emission intensity signal from the photoelectric conversion means as an emission waveform synchronized with plasma excitation. While monitoring the progress of the plasma processing based on the A / D conversion means for converting and the time change of the light emission waveform synchronized with the plasma excitation from the A / D conversion means, the light emission waveform changed to a specific waveform state. A plasma processing apparatus comprising: a plasma processing monitoring control unit configured to control the plasma processing on the object to be completed. 9. A plasma processing apparatus in which an object to be processed is subjected to plasma processing in a plasma processing chamber, wherein an optical element selectively detects only a specific wavelength light from an active species in plasma outside the plasma processing chamber. A system, photoelectric conversion means for converting light of a specific wavelength detected from the optical system into an emission intensity signal, A / D conversion means for A / D converting the emission intensity signal from the photoelectric conversion means by undersampling, A light emission waveform synthesizing means for synthesizing a light emission waveform synchronized with plasma excitation from sampling data over a plurality of plasma excitation periods from the A / D conversion means, and a time of the light emission waveform synchronized with plasma excitation from the light emission waveform synthesis means While monitoring the progress of the plasma processing based on the change, the plasma processing for the object to be processed is performed when the emission waveform changes to the specific waveform state. A plasma processing apparatus comprising: a plasma processing monitoring control unit that controls the processing to end. 10. A plasma processing apparatus in which an object to be processed is subjected to plasma processing in a plasma processing chamber, wherein the optical system selectively detects only light having a specific wavelength from active species in plasma outside the plasma processing chamber. System, photoelectric conversion means for converting light of a specific wavelength detected from the optical system into an emission intensity signal, and an A / D converter for detecting the emission intensity signal from the photoelectric conversion means as an emission waveform synchronized with plasma excitation. A / D conversion means for converting, light emission waveform correction means for correcting a light emission waveform from the A / D conversion means synchronized with plasma excitation by a light emission lifetime of the specific wavelength light, and light emission waveform correction means. Reaction synchronization component extraction means for extracting a light emission waveform component synchronized with the plasma processing reaction from the corrected light emission waveform, and a time change of the reaction synchronization light emission waveform component from the reaction synchronization component extraction means A plasma processing monitoring control means for controlling the plasma processing for the object to be processed based on the change of the emission waveform to a specific waveform state while monitoring the progress of the plasma processing based on the plasma processing. apparatus. 11. A plasma processing apparatus in which an object to be processed is subjected to plasma processing in a plasma processing chamber, wherein an optical element selectively detects only a specific wavelength light from active species in plasma outside the plasma processing chamber. System, photoelectric conversion means for converting light of a specific wavelength detected from the optical system into an emission intensity signal, and an A / D converter for detecting the emission intensity signal from the photoelectric conversion means as an emission waveform synchronized with plasma excitation. A / D conversion means for converting, and emission waveform correction means for correcting the emission waveform from the A / D conversion means synchronized with plasma excitation by deconvolution processing using the emission lifetime of the specific wavelength light as a parameter. Reaction synchronous component extracting means for extracting an emission waveform component synchronized with the plasma processing reaction from the corrected emission waveform from the emission waveform correction means; While monitoring the progress of the plasma processing based on the time change of the reaction-synchronous emission waveform component from the extracting means, the plasma is controlled to end the plasma processing for the object to be processed when the emission waveform changes to a specific waveform state. A plasma processing apparatus comprising processing monitoring control means. 12. A plasma processing apparatus in which an object to be processed is subjected to plasma processing in a plasma processing chamber, wherein an optical element selectively detects only a specific wavelength light from active species in plasma outside the plasma processing chamber. System, photoelectric conversion means for converting light of a specific wavelength detected from the optical system into an emission intensity signal, and an A / D converter for detecting the emission intensity signal from the photoelectric conversion means as an emission waveform synchronized with plasma excitation. A / D conversion means for converting, and emission waveform correction means for correcting an emission waveform from the A / D conversion means synchronized with plasma excitation by an emission decay rate curve determined by the emission lifetime of the specific wavelength light. A reaction synchronization component extraction unit that extracts a light emission waveform component synchronized with a plasma processing reaction from the corrected emission waveform from the emission waveform correction unit, and a reaction synchronization component extraction unit. Plasma processing monitoring control for monitoring the progress of the plasma processing based on the time change of the reaction-synchronous light emission waveform component and controlling the plasma processing for the object to be terminated when the light emission waveform changes to a specific waveform state. And a plasma processing apparatus. 13. A plasma processing apparatus in which an object to be processed is subjected to plasma processing in a plasma processing chamber, wherein an optical element selectively detects only specific wavelength light from active species in plasma outside the plasma processing chamber. System, photoelectric conversion means for converting light of a specific wavelength detected from the optical system into an emission intensity signal, and an A / D converter for detecting the emission intensity signal from the photoelectric conversion means as an emission waveform synchronized with plasma excitation. A / D conversion means for converting, and a light emission waveform synchronized with plasma excitation from the A / D conversion means, and a light emission lifetime of the specific wavelength light determined according to a plasma processing chamber pressure as a parameter. A light emission waveform correcting means for correcting by a deconvolution process, and extracting a light emission waveform component synchronized with a plasma processing reaction from the corrected light emission waveform from the light emission waveform correction means. A reaction synchronous component extracting means and a reaction synchronous emission waveform component from the reaction synchronous component extracting means monitor the progress of the plasma processing based on a temporal change, and when the light emission waveform changes to a specific waveform state, A plasma processing apparatus comprising: a plasma processing monitoring control unit that controls a plasma processing of a processing body to end. 14. A plasma processing apparatus main body in which an object to be processed is subjected to plasma processing in a plasma processing chamber.
A plasma processing monitoring device that is detachably attached so that the progress of the plasma processing can be constantly monitored, and selectively detects only a specific wavelength light from active species in the plasma outside the plasma processing chamber. And photoelectric conversion means for converting light of a specific wavelength detected from the optical system into an emission intensity signal; and A / D conversion for detecting the emission intensity signal from the photoelectric conversion means as an emission waveform synchronized with plasma excitation. A plasma processing monitoring apparatus including at least an A / D conversion means for performing the above-mentioned processing and a plasma processing monitoring means for monitoring the progress of the plasma processing based on a time change of a light emission waveform synchronized with plasma excitation from the A / D conversion means. 15. A plasma processing apparatus main body in which an object to be processed is subjected to plasma processing in a plasma processing chamber.
A plasma processing monitoring and control apparatus which is detachably added so that the progress of the plasma processing is constantly monitored and controlled, and selectively detects only a specific wavelength light from active species in plasma outside the plasma processing chamber. Optical system, photoelectric conversion means for converting the detection specific wavelength light from the optical system into a light emission intensity signal, the light emission intensity signal from the photoelectric conversion means,
To detect as an emission waveform synchronized with plasma excitation, A
A / D conversion means for performing A / D conversion, and monitoring the progress of plasma processing from the A / D conversion means based on a time change of a light emission waveform synchronized with plasma excitation, and changing the light emission waveform to a specific waveform state. A plasma processing monitoring and control device including at least plasma processing monitoring and controlling means for controlling the plasma processing on the object to be completed in response to the change.