JP2001250812A - Method and device for detecting end point of plasma treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and deice for detecting the end point of a plasma treatment by which the end point of the plasma treatment can be detected stably and accurately. SOLUTION: The device for detecting the end point of plasma etching is provided with a mass spectrometer 20 which monitors the change of the mass spectrum of a prescribed component of a gas in a process chamber 10, and five emission spectroscopic detectors 22 which monitor the change of the emission spectrum of a specific active species at five points on a wafer. The end point detection by means of the spectrometer 20 and detectors 22 is recognized when the difference between an end point signal obtained based on the monitored information by means of the spectrometer 20 and detectors 22 and preset reference information is <=10%. When the end point of plasma treatment is detected by means of the spectrometer 20 and detectors 22, it is comprehensively discriminated that the appropriate end point of plasma etching is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end point detecting method and an end point detecting apparatus for plasma processing, and more particularly to an end point detecting method and an end point detecting apparatus for detecting an etching end point in an etching process using plasma. .

[0002]

2. Description of the Related Art FIG.
This will be described with reference to a schematic sectional view of FIG. As shown in FIG. 3, a process chamber 10 which can be evacuated and into which an etching gas can be introduced is grounded, and a wafer (not shown) as an object to be processed is placed therein. Mounting table 12 is provided. Also,
An RF for outputting high-frequency power is provided on the wafer mounting table 12.
A (high frequency) power supply 14 is connected, and a pair of parallel plate electrodes is formed between the wafer mounting table 12 and the counter electrode 16 inserted into the process chamber 10.

When the RF power supply 14 is turned on, plasma is generated between the parallel plate electrodes composed of the wafer mounting table 12 and the counter electrode 16, and the plasma is used to generate the plasma. The wafer or the thin film on the surface of the wafer 12 can be entirely or selectively etched.

In such a plasma etching apparatus, as an end point detecting method for detecting an etching end point on a wafer, an emission spectral detection method, a mass spectrometry method, and the like have been conventionally used. In general, emission spectroscopy has the advantage that its implementation is simple and easy, and is widely used, but has the disadvantage that its close proximity to the emission spectrum of the measurement object makes its identification difficult. . Also,
Although mass spectrometry does not make it difficult to identify a mass spectrum, it has the disadvantage that the equipment is expensive.

Here, a description will be given of a case where the emission spectral detection method is used. That is, as shown in FIG. 3, for example, an emission spectrum detector 3 including a band-pass filter for selecting an emission spectrum of a specific active species, a photodetector, and the like.
0 is located adjacent to the process chamber 10,
Through a transparent plasma light extraction window 32 provided in the process chamber 10, a change in the emission spectrum of a specific active species at a predetermined point on the wafer on the wafer mounting table 12 can be monitored. Has become.

[0006] Based on the monitor information from the emission spectroscopy detector 30, the end point of the plasma etching process on the wafer mounted on the wafer mounting table 12 is detected. That is, when the change in the emission spectrum of a specific active species during the plasma etching process is monitored, the emission intensity of the emission spectrum changes as shown in the graph of FIG. 4, for example. Here, when the emission intensity of the emission spectrum in the plasma steady state is set to 100%, and the time when the emission intensity decreases to, for example, 50% is set as the end point of the plasma etching process, the emission spectrum detector 30 emits light of a specific active species. The emission intensity of the spectrum is, for example, 50%
It is determined that the plasma etching process on the wafer has reached the end point at the time point when the decrease is detected. Then, based on this determination, the RF power supply 14 is turned off, and the plasma etching process is completed.

[0007]

However, in the above-described conventional method for detecting the end point of plasma etching using the spectral emission detection method, the quartz / sapphire glass used for the window 32 for taking out plasma light as the number of etching processes increases. Is fogged, which makes it difficult to accurately detect the etching end point.

In addition, the plasma light extraction window 32 is usually provided at only one location, and the emission spectral detector 30 captures plasma light from the one plasma light extraction window 32. Since the change in the emission spectrum of a specific active species at a predetermined location on the wafer is monitored, the emission intensity of the emission spectrum changes periodically due to fluctuations and variations in plasma density, and noise is reduced. In such a case, it is difficult to accurately detect the etching end point on the entire surface of the wafer.

Further, as the pattern formed on the wafer becomes finer, the area to be selectively etched becomes smaller and the absolute amount of the reaction product also becomes smaller.
Since the emission intensity itself and the amount of change in the emission intensity of the emission spectrum of the specific active species shown in (1) also decrease, there is a problem that it is difficult to accurately detect the etching end point.

As described above, the emission spectrum detector 3
When the emission spectrum of a specific active species monitored by 0 is close to another emission spectrum, it becomes difficult to accurately detect only the emission intensity of the emission spectrum of the specific active species, and the However, there is a problem that it is difficult to accurately detect the etching end point.

Accordingly, the present invention has been made in view of the above problems, and when performing the plasma processing, even if the number of the plasma processing increases or the plasma density fluctuates or varies, the plasma processing is performed. It is an object of the present invention to provide an end point detection method and an end point detection device for plasma processing capable of stably and accurately detecting an end point of processing.

[0012]

The above object is achieved by the following method and apparatus for detecting an end point of plasma processing according to the present invention. That is, the method for detecting the end point of the plasma processing according to claim 1, when performing plasma processing on the object to be processed, while monitoring a change in the emission spectrum of a predetermined active species by emission spectroscopy, and by mass spectrometry, A change in a mass spectrum of a predetermined component is monitored, and an end point of the plasma processing on the object is detected based on both pieces of monitor information.

As described above, in the method for detecting the end point of the plasma processing according to the first aspect, the emission spectroscopy and the mass spectrometry are combined to monitor information on both the emission spectrum of a predetermined active species and the mass spectrum of a predetermined component. Based on
By detecting the end point of the plasma processing for the object to be processed, various detection limits in the case of using only one detection method are complemented by the other detection method, and the detection results obtained by these two detection methods are integrated to perform the plasma processing. Since the end point can be finally determined, the end point detection of the plasma processing with less error is realized.

For example, when only the emission spectroscopy is used, fogging occurs in a window for extracting plasma light with an increase in the number of processes, periodic changes in the emission intensity of the emission spectrum due to fluctuations and variations in plasma density, generation of noise, The emission intensity itself of the emission spectrum and the decrease in the variation of the emission intensity due to the decrease in the amount of reaction products due to the miniaturization of the pattern of the object to be processed, the emission spectrum of the specific active species, the proximity of other emission spectra to other emission spectra, etc. Due to this, the accuracy of end point detection may decrease, but the various detection limits of such end point detection by emission spectroscopy are complemented by end point detection by mass spectrometry. Therefore, the end point detection of the plasma processing with less error is realized.

According to a second aspect of the present invention, there is provided a method for detecting an end point of a plasma process, wherein when a plasma process is performed on an object to be processed, a change in the emission spectrum of a predetermined active species is detected at a plurality of locations on the object by an emission spectroscopy. , And simultaneously detects the end point of the plasma processing on the object to be processed based on the monitor information at a plurality of locations on the object to be processed.

Thus, in the method for detecting the end point of the plasma processing according to the second aspect, the plasma for the object to be processed is determined based on the monitor information obtained by simultaneously monitoring the change in the emission spectrum of the predetermined active species at a plurality of locations on the object to be processed. By detecting the end point of the processing, the periodic change of the light emission intensity of the light emission spectrum due to the fluctuation or variation of the plasma density or the occurrence of noise causes the accuracy of the entire object to be processed to be determined based on the monitor information at only one place. Even if it is difficult to detect the end point, it is possible to finally determine the end point of the plasma processing by integrating the detection results at a plurality of locations on the target object, so that the error with respect to the entire target object can be determined. The end point detection of the plasma processing with less noise is realized.

According to a third aspect of the present invention, in the method for detecting an end point of the plasma processing according to the first or second aspect, the monitor information is compared with predetermined reference information, and The end point of the plasma treatment on the body is determined.

Thus, in the method for detecting the end point of the plasma processing according to the third aspect, the monitor information on the emission spectrum and the mass spectrum by the emission spectroscopy and the mass spectrometry or the monitor on the emission spectrum at a plurality of positions of the object to be processed. By determining the end point of the plasma processing by comparing the information with the preset reference information, it is determined that an abnormality has occurred in the plasma processing in the case of the monitor information that is far apart from the reference information, and is fixed with respect to the reference information. Only when the monitor information is within the range, the end point of the plasma processing can be determined based on the monitor information, so that the detection of the end point of the plasma processing with less error is realized.

According to a fourth aspect of the present invention, there is provided an apparatus for detecting an end point of a plasma process, comprising: an emission spectrum detector for monitoring a change in an emission spectrum of a predetermined active species when performing a plasma process on the object; A mass analyzer that monitors a change in the mass spectrum of a predetermined component when performing the plasma processing, and an end point of the plasma processing for the object to be processed based on the monitor information from the emission spectrum detector and the monitor information from the mass analyzer. And a determination processing unit that determines

As described above, the apparatus for detecting the end point of the plasma processing according to the fourth aspect includes both the emission spectrum detector and the mass spectrometer, and the emission spectrum of the predetermined active species and the mass spectrum of the predetermined component from both. The detection processing unit detects the end point of the plasma processing for the object to be processed based on the monitor information for both of them, thereby supplementing various detection limits when only one detector is used by using the other detector. However, since it is possible to finally determine the end point of the plasma processing by combining the detection results of these two detectors, the end point detection of the plasma processing with less error is realized.

For example, when only the emission spectrum detector is used,
Occurrence of fogging in the plasma light extraction window due to an increase in the number of treatments, periodic changes in the emission intensity of the emission spectrum due to fluctuations and variations in plasma density, generation of noise, and reactions associated with miniaturization of the pattern of the workpiece Due to the decrease in the emission intensity itself of the emission spectrum or the change in the emission intensity due to the decrease in the amount of the product, the proximity of the emission spectrum of the specific active species to another emission spectrum, etc., the accuracy of the end point detection decreases. However, the various detection limits of end point detection using such an emission spectroscopic detector are complemented by end point detection using a mass spectrometer, and the end point of comprehensive plasma processing is determined. Processing end point detection is realized.

According to a fifth aspect of the present invention, there is provided an apparatus for detecting an end point of a plasma processing, wherein a plurality of windows provided in a chamber for accommodating the processing object, and the plasma processing is performed on the processing object through the plurality of windows, respectively. A plurality of emission spectral detectors that simultaneously monitor changes in the emission spectrum of a predetermined active species at the time of application at a plurality of locations on the object, and monitor information from the plurality of emission spectrum detectors at a plurality of locations on the object. A determination processing unit that determines an end point of the plasma processing on the object to be processed based on the determination processing unit.

As described above, the apparatus for detecting the end point of the plasma processing according to the fifth aspect is provided with a plurality of emission spectral detectors, and through a plurality of windows provided in the chamber, respectively.
By simultaneously monitoring changes in the emission spectrum of a predetermined active species at a plurality of locations on the workpiece, and detecting the end point of the plasma processing on the workpiece in the determination processing unit based on the monitor information, the fluctuation of the plasma density or the like can be prevented. Even if it is difficult to accurately detect the end point of the entire object to be processed based on the monitor information at only one location due to the periodic change of the emission intensity of the emission spectrum or the occurrence of noise due to the variation, Since it is possible to finally determine the end point of the plasma processing by integrating the detection results at a plurality of locations on the body, the end point detection of the plasma processing with less error for the entire object to be processed is realized.

According to a sixth aspect of the present invention, there is provided the plasma processing end point detecting apparatus according to the fourth or fifth aspect, wherein the determination processing section includes a memory for storing preset reference information. And determining the end point of the plasma processing for the object to be processed by comparing the monitor information with the reference information stored in the memory.

Thus, in the apparatus for detecting the end point of the plasma processing according to claim 6, in the determination processing section, monitor information on the emission spectrum and the mass spectrum by the emission spectrum detector and the mass analyzer or the plurality of emission spectrum detectors. By comparing the monitor information on the emission spectrum at a plurality of positions of the object to be processed with the reference information stored in the memory to determine the end point of the plasma processing, the plasma processing is performed in the case of the monitor information far apart from the reference information. It is determined that an abnormality has occurred, and only when the monitor information is within a certain range with respect to the reference information, the end point of the plasma processing can be determined based on the monitor information. Processing end point detection is realized.

[0026]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described. FIG. 1 is a schematic sectional view showing a plasma etching apparatus provided with an apparatus for detecting an end point of a plasma etching process according to an embodiment of the present invention, and FIG. 2 is a diagram showing an end point detection of the plasma etching processing in the plasma etching apparatus shown in FIG. It is a flowchart for explaining operation.

As shown in FIG. 1, in the plasma etching apparatus according to the present embodiment, as in the ordinary plasma etching apparatus shown in FIG. 3, it is possible to evacuate and introduce an etching gas. A possible process chamber 10 is grounded, and a wafer mounting table 12 for mounting a wafer (not shown) as an object to be processed is provided therein. Also, the wafer mounting table 1
2 is connected to an RF power source 14 for outputting high-frequency power.
A pair of parallel plate electrodes is formed with the counter electrode 16 inserted in the inside.

By turning on the RF power source 14 in this manner, a plasma is generated between the parallel plate electrodes composed of the wafer mounting table 12 and the counter electrode 16, and this plasma is used to generate a plasma on the wafer mounting table 12. The wafer or the thin film on the surface of the wafer can be entirely or selectively etched.

In the plasma etching apparatus according to this embodiment, unlike a normal plasma etching apparatus, for example, five transparent plasma light extraction windows (however, in FIG. In order to avoid complication, only one plasma light extraction window is displayed) 18.

As shown in FIG. 1, an end point detecting device (End Poin) for detecting the end point of the plasma etching process.
t Detector), for example, five mass spectrometers 20 and five emission spectrometers (only one emission spectrometer is shown in FIG. 1 to avoid complication in the drawing) 2
2 are installed.

The mass analyzer 20 is arranged so as to be connected to the process chamber 10 and can monitor a change in the mass spectrum of a predetermined component of the gas in the process chamber 10 during the plasma etching process. I have. The five emission spectroscopy detectors 22 are respectively disposed adjacent to the five plasma light extraction windows 18, and the wafer mounting table during the plasma etching process is connected through the respective plasma light extraction windows 18. It is possible to monitor changes in the emission spectrum of a specific active species at five locations distributed on the wafer mounted on the substrate 12.

The mass spectrometer 20 and the five emission spectroscopic detectors 22 are connected to a judgment processing unit 24 for judging the end point of the plasma etching processing. And CPU (Central
Processing Unit) 28 is provided.

Then, the memory 26 of the determination processing unit 24
, The mass spectrometer 20 and the five emission spectroscopy detectors 2
2 stores the monitor information of the mass spectrum of the predetermined component of the gas in the process chamber 10 during the plasma etching process and the monitor information of the emission spectrum of the specific active species at five locations on the wafer. The reference information set in advance based on the experiment described above and data accumulated so far is stored.

Further, the CPU 28 of the determination processing unit 24 compares the monitor information read from the memory 26 with the reference information to determine whether the monitor information is appropriate, and finally determines the end point of the plasma etching process. Has become.

Next, the operation of detecting the end point of the plasma etching process in the plasma etching apparatus shown in FIG. 1 will be described with reference to the flowchart of FIG. First, a predetermined etching gas is introduced into the process chamber 10 in a high vacuum state of the plasma etching apparatus, and the RF power supply 14 is turned on.
A plasma is generated between the parallel plate electrodes composed of the wafer mounting table 12 and the counter electrode 16, and this plasma is used to entirely or selectively generate a thin film on the wafer or wafer surface on the wafer mounting table 12. The etching process is started (Step S1).

Simultaneously with the start of the plasma etching process, the mass spectrometer 20 monitors the mass spectrum of a predetermined component of the gas in the process chamber 10 and sets the monitor 5.
Monitoring of emission spectra of specific active species at five locations on the wafer by the two emission spectrometers 22 is started (step S2-1, step S2-).
2).

The mass spectrum of a predetermined component of the gas during the plasma etching process and the emission spectrum of a specific active species at five locations on the wafer are monitored by the mass analyzer 20 and the five emission spectrometers 22. Is sent from the mass analyzer 20 and the five emission spectroscopy detectors 22 to the determination processing unit 24, respectively. In the CPU 28 of the determination processing unit 24, the monitor information from the mass analyzer 20 is within a predetermined range,
It is determined whether or not an end point signal is obtained based on the monitor information (step S3-1). If the end point signal is obtained, that is, if Y (Yes; affirmative) in step S3-1, the monitor is monitored. The information is stored and stored as data in the memory 26 (step S4-1).

Similarly, in the CPU 28, monitor information from the five emission spectroscopic detectors 22 is within a predetermined range, and based on the monitor information, at least four out of five places on the wafer have an end point signal. Is determined (step S3-2), and if the end point signal is obtained in at least four of the five positions, that is, if Y is obtained in step S3-2, the monitor information is stored in the memory 26. The data is stored and stored (step S4-2).

Next, in the CPU 28 again, the monitor information from the mass analyzer 20 stored in the memory 26 and the end point signal obtained based on the monitor information are compared with predetermined reference information. % Is determined (step S5-1), and the difference is 10%.
%, That is, if Y in step S5-1, it is determined that the end point has been detected based on the monitor information from the mass analyzer 20.

Similarly, in the CPU 28, the memory 26
Is compared with the monitor information from the five emission spectroscopic detectors 22 stored in the memory and the end point signal obtained based on the monitor information and predetermined reference information, and determines whether the difference is within 10%, for example. (Step S5-2), and if the difference is within 10%, that is, if Y in step S5-2, the end point is detected based on the monitor information from the five emission spectral detectors 22. It is recognized that it has been done.

Next, it is determined whether or not the end point has been detected by both the mass spectrometer 20 and the five emission spectroscopic detectors 22 (step S6), and when the end point has been detected by both detectors. That is, in the case of Y in step S6, it is determined that an appropriate end point of the plasma etching process has been comprehensively detected, and an end point detection signal is output from the CPU 28 (step S7). CP of this determination processing unit 24
Upon receiving the end point detection signal from U28, the RF power supply 14 of the plasma etching apparatus is turned off, and the normal plasma etching processing ends (step S8).

On the other hand, when the CPU 28 of the determination processing section 24 determines whether or not the monitor information from the mass spectrometer 20 is within a predetermined range and the end point signal is obtained based on the monitor information, the end point is determined. If no signal is obtained, that is, if N (No; negative) in step S3-1,
It is determined that an abnormality has occurred in the plasma etching process,
An abnormality occurrence signal (error signal) is output from the CPU 28 (step S9).

Similarly, in the CPU 28, the monitor information from the five emission spectroscopy detectors 22 is within a predetermined range, and based on the monitor information, at least four out of five places on the wafer have an end point signal. When it is determined whether or not an error is obtained, when the end point signal is not obtained, that is, in the case of N in step S3-2, it is also determined that an abnormality has occurred in the plasma etching process, and an abnormality occurrence signal is output from the CPU 28. Is output (step S9).

The CPU 28 compares the monitor information from the mass spectrometer 20 stored in the memory 26 and the end point signal obtained based on the monitor information with predetermined reference information, and the difference is, for example, 10%. If it is not within 10%, that is, if it is N in step S5-1, it is determined that the end point of the plasma etching process is not appropriate, and the CPU 28 outputs an abnormality occurrence signal. (Step S9).

Similarly, in the CPU 28, the memory 26
Is compared with the monitor information from the five emission spectroscopic detectors 22 stored in the memory and the end point signal obtained based on the monitor information and predetermined reference information, and determines whether the difference is within 10%, for example. Is not within 10%, that is, also in the case of N in step S5-2, it is determined that the end point of the plasma etching process is not appropriate, and C
An abnormality occurrence signal is output from the PU 28 (step S
9).

Upon receiving the abnormality occurrence signal from the CPU 28 of the determination processing section 24, the RF power supply 14 of the plasma etching apparatus is turned off, and it is determined that an abnormality has occurred in the plasma etching processing or the end point of the plasma etching processing is not appropriate. The abnormal or improper plasma etching process ends (step S10).

As described above, according to the present embodiment, the mass analyzer 20 for monitoring the change in the mass spectrum of a predetermined component of the gas in the process chamber 10 and the mass spectrometer 20 on the wafer are used as the end point detecting device for the plasma etching process. It is provided with five emission spectroscopy detectors 22 for monitoring changes in emission spectra of specific active species at five locations, and whether or not an end point signal is obtained based on monitor information from one mass spectrometer 20. It is determined whether the difference from the reference information set in advance is within 10%, the end point detection by the mass spectrometer 20 is authorized, and the wafer is determined based on the monitor information from the other five emission spectral detectors 22. It is determined whether or not an end point signal is obtained in at least four of the above five locations, and whether or not a difference from reference information set in advance is within 10%. The end point detection by the detector 22 is recognized, and when the end point is detected by both the mass spectrometer 20 and the five emission spectroscopic detectors 22, the appropriate end point of the plasma etching process is comprehensively determined. Assuming that the end point is detected, even if fogging occurs in the plasma light extraction window 18 as the number of processes increases, the emission intensity of the emission spectrum periodically changes due to fluctuations and variations in plasma density. Or the occurrence of noise, even if the emission intensity itself of the emission spectrum or the amount of change in the emission intensity decreases due to the reduction in the amount of reaction products due to the miniaturization of the pattern formed on the wafer, the specific active species Even in the case where the emission spectrum is close to another emission spectrum, it is possible to prevent a decrease in the accuracy of end point detection due to these factors, and to reduce the error in the plasma etching. It is possible to realize the end-point detection process.

In the above embodiment, the number of the plasma light extraction window 18 provided in the process chamber 10 and the number of the emission spectral detectors 22 adjacent to the window 18 are five, but this number is reduced to five. It is not limited. As this number increases, the accuracy of detecting the end point of the plasma etching process on the entire wafer surface increases even when the emission intensity of the emission spectrum periodically changes or noise occurs due to fluctuations or variations in the plasma density. However, on the other hand, the device may be complicated, so that an appropriate number may be set in consideration of the two.

In step S4-2, the validity criterion for obtaining the end point signal based on the monitor information from the five emission spectroscopy detectors 22 is changed to the end point signal in at least four out of five places on the wafer. Although it is assumed that it can be obtained, the validity criterion can be set arbitrarily, and appropriate values can be set according to the periodic change of the emission intensity of the emission spectrum and the degree of noise generation due to fluctuations and variations in the plasma density. What is necessary is just to set an effective criterion.

Steps S5-1 and S5
-2, when the monitor information from the mass spectrometer 20 and the five emission spectral detectors 22 and the end point signal obtained based on the monitor information are compared with predetermined reference information, the difference is, for example, If it is within 10%, it is determined that the end point has been detected based on the monitor information from the mass spectrometer 20 and the five emission spectrometers 22. However, the comparison standard is not limited to 10%. , And can be set to any value. Specifically, an appropriate value may be set in consideration of the film thickness of the object to be etched, the variation in the plasma etching rate, and the like.

[0051]

As described above in detail, according to the method and the apparatus for detecting the end point of the plasma processing according to the present invention, the following effects can be obtained. That is, according to the method for detecting the end point of the plasma processing according to the first aspect, the emission spectroscopy and the mass spectrometry are combined, and based on the monitor information on the emission spectrum of the predetermined active species and the mass spectrum of the predetermined component, the target is detected. By detecting the end point of the plasma processing for the processing object, various detection limits when only one detection method is used are complemented by the other detection method, and the detection results obtained by these two detection methods are integrated to end the plasma processing. Can be finally determined, and the end point detection of the plasma processing with less error can be realized.

Further, according to the method for detecting the end point of the plasma processing according to the second aspect, the plasma for the object to be processed is determined based on monitor information obtained by simultaneously monitoring changes in the emission spectrum of a predetermined active species at a plurality of locations on the object. By detecting the end point of the processing, even if the emission intensity of the emission spectrum changes periodically or noise occurs due to fluctuations or variations in the plasma density, the detection results at a plurality of locations on the object to be processed can be obtained. Since the end point of the plasma processing can be finally determined as a whole, it is possible to realize the end point detection of the plasma processing with less error for the entire object to be processed.

According to the method for detecting the end point of the plasma processing according to the third aspect, the monitor information on the emission spectrum and the mass spectrum by the emission spectroscopy and the mass spectrometry or the monitor on the emission spectrum at a plurality of places on the object to be processed. By determining the end point of the plasma processing by comparing the information with the preset reference information, it is determined that an abnormality has occurred in the plasma processing in the case of the monitor information that is far apart from the reference information, and is fixed with respect to the reference information. Since the end point of the plasma processing can be determined only when the monitor information is within the range, the detection of the end point of the plasma processing with less error can be realized.

According to the apparatus for detecting the end point of the plasma processing according to the fourth aspect, both the emission spectrum detector and the mass spectrometer are provided, and the emission spectrum of the predetermined active species and the mass spectrum of the predetermined component from both are provided. Based on the monitor information about, by detecting the end point of the plasma processing on the object to be processed in the determination processing unit, various detection limits in the case of using only one detector are complemented by using the other detector, Since it is possible to finally determine the end point of the plasma processing by combining the detection results of these two detectors, it is possible to realize the end point detection of the plasma processing with less error.

According to the apparatus for detecting the end point of the plasma processing according to the fifth aspect, a plurality of emission spectroscopy detectors are provided, and a plurality of emission spectroscopy detectors are provided at a plurality of locations on the object to be processed through a plurality of windows provided in the chamber. At the same time, the change in the emission spectrum of the active species is monitored, and based on the monitor information, the determination processing unit detects the end point of the plasma processing for the object to be processed, so that the emission intensity of the emission spectrum is changed due to fluctuation or variation in the plasma density. Even in the case of periodic changes or noise, it is possible to finally determine the end point of the plasma processing by integrating the detection results at a plurality of locations on the processing target. It is possible to realize the end point detection of the plasma processing with less error for the whole body.

According to the apparatus for detecting the end point of the plasma processing according to the sixth aspect, in the determination processing section, monitor information on the emission spectrum and the mass spectrum by the emission spectrum detector and the mass analyzer or the plurality of emission spectrum detectors. By comparing the monitor information on the emission spectrum at a plurality of positions of the object to be processed with the reference information stored in the memory to determine the end point of the plasma processing, the plasma processing is performed in the case of the monitor information far apart from the reference information. It is determined that an abnormality has occurred, and only when the monitor information is within a certain range with respect to the reference information, the end point of the plasma processing can be determined based on the monitor information. Detection of the end point of the processing can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a plasma etching apparatus provided with an apparatus for detecting an end point of a plasma etching process according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining an end point detection operation of a plasma etching process in the plasma etching apparatus shown in FIG. 1;

FIG. 3 is a schematic sectional view showing a plasma etching apparatus provided with a conventional emission spectral detector.

4 is a graph showing a change in emission intensity of an emission spectrum in the plasma etching apparatus shown in FIG.

[Explanation of symbols]

10 process chamber 12 wafer mounting table
14 RF power supply 16 Counter electrode 18 Window for plasma light extraction 20 Mass spectrometer 22 Emission spectroscopy detector 24 Judgment processing unit 26 Memory 28
... CPU, 30... Emission spectral detector, 32... Window for extracting plasma light.

Claims (6)

[Claims] When a plasma treatment is performed on an object to be processed, a change in an emission spectrum of a predetermined active species is monitored by emission spectroscopy, and a change in a mass spectrum of a predetermined component is monitored by mass spectrometry. And detecting an end point of the plasma processing for the object to be processed based on both pieces of monitor information. 2. A method according to claim 1, wherein, when performing plasma processing on the object to be processed, a change in an emission spectrum of a predetermined active species is simultaneously monitored at a plurality of positions on the object by emission spectroscopy. Detecting an end point of the plasma processing for the object to be processed based on the monitor information in the step (a). 3. The end point detection method for plasma processing according to claim 1, wherein the end point of the plasma processing for the object is determined by comparing the monitor information with reference information set in advance. Method for detecting end point of plasma processing. 4. An emission spectrometer for monitoring a change in an emission spectrum of a predetermined active species when performing plasma processing on the object, and a mass spectrum of a predetermined component when performing plasma processing on the object. Mass spectrometer that monitors the change of, and a determination processing unit that determines the end point of the plasma processing on the object to be processed based on the monitor information from the emission spectrometer and the monitor information from the mass spectrometer. An end point detection device for plasma processing, comprising: 5. A plurality of windows provided in a chamber accommodating an object to be processed, and a change in an emission spectrum of a predetermined active species when performing plasma processing on the object to be processed through each of the plurality of windows. A plurality of emission spectral detectors that simultaneously monitor the plurality of locations of the object, and a plasma processing for the object based on monitor information at the plurality of locations of the object from the plurality of emission spectral detectors. An end point detection apparatus for plasma processing, comprising: a determination processing unit that determines an end point. 6. The plasma processing end point detection device according to claim 4, wherein the determination processing unit has a memory for storing preset reference information, and the monitor information is stored in the memory. An end point detection apparatus for plasma processing, wherein an end point of plasma processing for the object to be processed is determined in comparison with reference information.