JP4041579B2 - End point detection method of plasma processing and semiconductor device manufacturing method using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing end point detection method and apparatus, and a semiconductor device manufacturing method and apparatus using the same, and in particular, a method suitable for processing a substrate with plasma generated in a processing chamber. And an apparatus for the same.
[0002]
[Prior art]
Starting with an etching apparatus, a process using plasma is widely applied to a semiconductor manufacturing process and a liquid crystal display substrate manufacturing process.
[0003]
The conventional technique will be described using the etching apparatus shown in FIG. 14 as an example. In this etching apparatus, a high voltage from a high-frequency power source 5 is applied between an upper electrode 2 and a lower electrode 3 arranged in parallel in the processing chamber 1, and plasma is generated from an etching gas by discharge between both electrodes. 6 is generated, and the semiconductor wafer 4 as an object to be processed is etched by the active species. In the etching process, the progress of etching is monitored, the end point thereof is detected as accurately as possible, and the etching process is performed for a predetermined pattern shape and depth. The power supply frequency of the high frequency power supply 5 is, for example, about 400 kHz.
[0004]
Conventionally, methods such as spectroscopic analysis and mass spectrometry have been used as methods for detecting the end point of etching. Among them, as shown in Japanese Patent Application Laid-Open No. 6-28252, spectroscopic analysis is simple and sensitive. Is widely used. Specifically, a specific active species is selected from active species such as radicals and ions such as an etching gas, its decomposition products, or reaction products, and the emission intensity of the emission spectrum of the selected active species is measured. . That is, in FIG. 14, light emission 8 from plasma is dispersed by a spectroscope 9 such as a monochromator through a window 7 and only a light emission component 10 having a desired wavelength is extracted. This luminescent component 10 is received by a photoelectric conversion element 11 such as a photomultiplier, converted into an electric signal, amplified by an amplifier 12 having a bandwidth of about 100 to several kHz which is sufficiently lower than a high frequency power source for plasma excitation, and then an end point is determined. Sent to the unit 13.
[0005]
The end point determination unit 13 observes the temporal change 15 of the emission intensity as shown in FIG. 15, and presets the emission intensity at the change point, its primary differential value, secondary differential value, or the like. By comparing with the threshold value S, the etching end point position E is determined. When the end point is detected, the power supply control device 14 stops the output of the high frequency power supply 5. In this method, since the band of the amplifier 12 is sufficiently lower than the plasma excitation frequency, the DC component of the plasma emission is detected.
[0006]
The active species to be selected varies depending on the type of etching gas. For example, when a silicon oxide film is etched using a fluorocarbon-based etching gas such as CF, an emission spectrum from CO (219 nm or 483.5 nm) as a reaction product, or an intermediate product An emission spectrum (such as 260 nm) from a certain CF is measured.
[0007]
[Problems to be solved by the invention]
According to the prior art, the end point of etching can be obtained with a simple configuration. However, with the miniaturization of the semiconductor circuit pattern, the total area of the etched portion is reduced, and the absolute amount of the reaction product tends to decrease. As a result, as indicated by the alternate long and short dash line 16 in FIG. 15, the emission intensity itself decreases and the amount of change in the emission intensity at the end point position decreases significantly, resulting in etching of the resist material and the quartz member in the processing chamber 1. The influence of background noise such as generation of reaction products and 1 / f noise such as plasma fluctuation becomes relatively large, and it is difficult to determine the end point position.
[0008]
In order to solve these problems, for example, as shown in Japanese Patent Application Laid-Open No. 59-61036, a method for improving the amplitude of the signal at the end point by calculating the ratio using two emission signals, As disclosed in Japanese Patent Laid-Open No. 6-229827, in order to reduce the influence of 1 / f noise, instead of detecting the DC component of plasma emission, the plasma emission is modulated by a chopper, A method of demodulating with a lock-in amplifier using a reference signal or an RF signal for plasma generation without using a chopper as a reference signal has been proposed.
[0009]
Further, instead of simply extracting only the chopping frequency component from the light emission signal, only the component synchronized with the etching reaction is selectively extracted as shown in Japanese Patent Application Laid-Open No. 9-115883, so that the signal at the end point is obtained. A method for realizing the change has also been proposed. According to this method, an improvement in the accuracy of detecting the etching end point in a fine pattern can be expected. However, in the field of semiconductors that are highly integrated into 256 Mbit DRAMs and further to 1 Gbit DRAMs, circuit pattern miniaturization is not limited. Particularly in contact hole etching, the area of an etched portion is 0. It is about to reach 5%. In the etching of such a finer pattern, it is difficult to detect the end point with high accuracy even if the above method is used.
[0010]
On the other hand, also in the etching apparatus main body, reaction products and the like are deposited on the window of the processing chamber with the etching reaction, the transmittance of the window decreases, the amount of detected light decreases, and the end point detection becomes more difficult. Has occurred.
[0011]
An object of the present invention is to detect the end point of processing of a substrate to be processed using plasma, which can always detect the end point of plasma processing stably and with high accuracy without being affected by the miniaturization of the pattern to be processed and disturbance. It is an object to provide a method and an apparatus thereof, and a semiconductor manufacturing method and an apparatus using the method.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a method for detecting an end point of processing of a substrate to be processed using plasma, light having a predetermined wavelength of plasma emission during processing of the substrate to be processed is detected. A signal component that changes in accordance with the progress of processing by the plasma is extracted from the detected light emission signal of the predetermined wavelength at a predetermined cycle, and the end point of the processing by the plasma based on the change in intensity of the extracted signal component It was made to detect.
[0013]
The signal component that changes with the progress of the plasma processing is a component that is synchronized with the frequency of the high frequency power source for plasma excitation that generates plasma or an integral multiple thereof.
[0014]
In addition, the signal component that changes in accordance with the progress of the plasma processing is a component synchronized with the frequency of the power source of the high-frequency power applied to the mounting table on which the substrate to be processed is mounted, or an integral multiple thereof.
[0015]
Further, the light having a predetermined wavelength of the light emission of the plasma being detected is made to be a light emission signal of a reaction product generated by the plasma treatment.
[0016]
In addition, the light having a predetermined wavelength of the light emission of the plasma during the processing to be detected is made to be a light emission signal of a reaction gas or an intermediate product used for the plasma processing.
[0017]
Furthermore, the present invention relates to a method of processing a substrate to be processed using plasma, with light having a wavelength component whose emission intensity increases with processing from the light emission of plasma during processing of the substrate to be processed. Separates and detects light of a wavelength component whose emission intensity decreases, extracts light of a wavelength component whose emission intensity increases and light of a wavelength component whose emission intensity decreases, respectively, at a predetermined cycle, and extracts this The end point of the plasma treatment is detected based on the change in the intensity of the light of the wavelength component that increases the emission intensity and the light of the wavelength component that decreases the emission intensity.
[0018]
Then, extraction at a predetermined cycle is performed at a high frequency of a high frequency power source for generating plasma, or a cycle of an integral multiple thereof.
[0019]
In order to achieve the above object, according to the present invention, in a method for manufacturing a semiconductor device, plasma is generated inside a processing chamber in which a substrate to be processed is arranged, the substrate to be processed is processed by the plasma, The light of a predetermined wavelength of the light emission of the plasma is detected, and a signal component that changes in accordance with the progress of the processing by the plasma is extracted from the light emission signal of the light of the predetermined wavelength thus detected. The end point of the plasma processing is detected based on the change in the intensity of the signal component, and the processing of the target substrate is terminated based on the detected plasma processing end point.
[0020]
Then, the processing of the substrate to be processed by plasma is a plasma etching process.
[0021]
Further, the present invention relates to a method for manufacturing a semiconductor device, in which plasma is generated inside a processing chamber in which a substrate to be processed is arranged, the substrate to be processed is processed with plasma, and plasma emission during processing is accompanied by processing. The wavelength component light whose emission intensity increases and the wavelength component light whose emission intensity decreases with processing are detected separately, and the wavelength component light whose emission intensity increases and the wavelength component whose emission intensity decreases And the end point of the plasma processing is detected based on the change in intensity between the extracted wavelength component light that increases the emission intensity and the wavelength component light that decreases the emission intensity. Then, the processing of the substrate to be processed is completed based on the detected end point of the plasma processing.
[0022]
Then, the processing of the substrate to be processed by plasma is a plasma etching process.
[0023]
Further, the present invention provides a method for manufacturing a semiconductor device, wherein plasma is generated inside a processing chamber in which a substrate to be processed is disposed, the substrate to be processed is processed by the plasma, and light having a predetermined wavelength of the plasma being processed is emitted. The emission intensity is detected at a plurality of locations above the substrate to be processed, and the end point of the plasma processing is detected based on the change in the emission intensity of light of a predetermined wavelength at the detected plurality of locations, and the detected plasma is used. The processing of the substrate to be processed is completed based on the end point of the processing.
[0024]
Then, the processing of the substrate to be processed by plasma is a plasma etching process.
[0025]
Further, the present invention provides a method of manufacturing a semiconductor device, wherein plasma is generated inside a processing chamber in which a substrate to be processed is arranged, the substrate to be processed is processed by the plasma, and light having a predetermined wavelength of plasma being processed is processed. The emission intensity of the plasma is detected, the state of treatment with plasma is determined from the emission intensity of light of a predetermined wavelength when a preset time has elapsed, and the state of treatment with plasma thus determined is compared with preset data When the plasma processing state determined by this comparison is different from preset data, an abnormal signal is transmitted.
[0026]
Then, the processing of the substrate to be processed by plasma is terminated when a preset time has elapsed.
[0027]
Furthermore, in order to achieve the above object, the present invention provides an apparatus for detecting an end point of processing of a substrate to be processed using plasma, and detects light of a predetermined wavelength of plasma emission during processing of the substrate to be processed. A detecting means, an extracting means for extracting a signal component that changes in accordance with the progress of processing by the plasma from a light emission signal of a predetermined wavelength detected by the detecting means, and an extracting means that extracts the signal component Detecting means for detecting the end point of the plasma processing based on the change in the intensity of the signal component.
[0028]
The predetermined period for extracting the signal component by the extracting means is a component synchronized with the high frequency of the high frequency power applied to the plasma generating means or an integral multiple thereof.
[0029]
Further, the mounting table on which the substrate to be processed is mounted is connected to a high frequency power source, and the predetermined period for extracting the signal component by the extracting means is the frequency of the high frequency power source connected to the mounting table, or an integral multiple thereof. The components are synchronized.
[0030]
The light emission detecting means detects the light emission of the reaction product generated by the plasma treatment.
[0031]
Further, the light emission detecting means detects the light emission of the intermediate product generated by the gas introduced from the gas introduction part or the plasma treatment.
[0032]
Further, the light emission detecting means is constituted by an imaging optical system provided with a light receiving element in an imaging relationship with plasma.
[0033]
In order to achieve the above object, the present invention provides a semiconductor device manufacturing apparatus, a processing chamber means having a mounting table on which a substrate to be processed is mounted and a gas introducing unit, and a gas introduced by a gas introducing unit. Plasma generating means for generating plasma inside the processing chamber means into which the plasma is introduced, and light having a predetermined wavelength of plasma emission during processing of the substrate to be processed placed on the mounting table by the plasma generated by the plasma generating means A light emission detecting means for detecting a signal, and an extraction for extracting a signal component that changes in accordance with the progress of processing of the substrate to be processed by plasma from a light emission signal of light having a predetermined wavelength detected by the light emission detecting means at a predetermined cycle Means, an end point detecting means for detecting the end point of the plasma processing based on the change in intensity of the signal component extracted by the extracting means, and the end of the processing by the plasma detected by the end point detecting means. It was constructed and a control means for terminating the processing of the substrate based on.
[0034]
And the process of the to-be-processed substrate by plasma was made into the plasma etching process.
[0035]
Further, the present invention provides a semiconductor device manufacturing apparatus comprising: a processing chamber means having a mounting table on which a substrate to be processed is placed; and a gas introducing portion; and a processing chamber means having a gas introduced by the gas introducing portion. And a wavelength component whose emission intensity increases from the emission of the plasma during the processing of the substrate to be processed placed on the mounting table by the plasma generated by the plasma generation means. The light emission detecting means for separately detecting the light of the wavelength component and the light of the wavelength component for which the light emission intensity decreases with the processing, and the light of the wavelength component for which the light emission intensity detected by the light emission detecting means is increased and the light emission intensity are reduced. The extraction means for extracting the light of the wavelength component to be emitted at a predetermined period, and the change in intensity between the light of the wavelength component that increases the emission intensity and the light of the wavelength component that decreases the emission intensity extracted by the extraction means. And end detecting means for detecting the end point of the process by the plasma Zui was constructed and a control means for terminating the processing of the substrate based on the end point of the treatment by plasma detected by the endpoint detector.
[0036]
And the process of the said to-be-processed substrate by plasma was made to be a plasma etching process.
[0037]
Further, the present invention provides a semiconductor device manufacturing apparatus comprising: a processing chamber means having a mounting table on which a substrate to be processed is placed; and a gas introducing portion; and a processing chamber means having a gas introduced by the gas introducing portion. A plasma generating means for generating plasma, and a light emission intensity of light of a predetermined wavelength of the plasma above the substrate to be processed while processing the substrate to be processed placed on the mounting table by the plasma generated by the plasma generating means. Luminescence detection means for detecting at a plurality of locations, end point detection means for detecting the end point of processing by plasma based on the change in the emission intensity of light of a predetermined wavelength at the plurality of locations detected by the light emission detection means, and this endpoint And control means for terminating the processing of the substrate to be processed based on the end point of the plasma processing detected by the detecting means.
[0038]
Then, the end point of the plasma processing by the end point detecting means is detected, the light emission intensity of the light of a predetermined wavelength is extracted at a predetermined period, and the change of the light emission intensity of the light of the predetermined wavelength in the extracted predetermined period is detected. Based on that.
[0039]
Further, the present invention provides a semiconductor device manufacturing apparatus comprising: a processing chamber means having a mounting table on which a substrate to be processed is placed; and a gas introducing portion; and a processing chamber means having a gas introduced by the gas introducing portion. Plasma generating means for generating plasma in the plasma, and light emission detection for detecting light emission intensity of light having a predetermined wavelength of plasma emission during processing of the substrate to be processed placed on the mounting table by the plasma generated by the plasma generating means Means, determination means for determining the state of processing by plasma from the light emission intensity of light of a predetermined wavelength when a preset time has elapsed, and data for which the state of processing by plasma determined by this determination means is set in advance An abnormal signal is transmitted when the state of the plasma processing determined by the determination means by the comparison means by the comparison means differs from the preset data. Constructed by a transmitting means.
[0040]
The apparatus further includes control means for terminating the processing of the substrate to be processed by plasma when a preset time has elapsed.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0042]
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an etching apparatus and an etching end point detection apparatus in the first embodiment. The etching end point detection apparatus includes a light emission detection optical system 101 and a signal processing / determination / control system 201.
[0043]
In this embodiment, the etching apparatus is a parallel plate plasma etching apparatus. The output voltage of the power amplifier 38 is modulated by the high frequency signal from the signal generator 37, this high frequency voltage is distributed by the distributor 39, and is disposed between the upper electrode 2 and the lower electrode 3 arranged in parallel in the processing chamber 1. The plasma 6 is generated from the etching gas by applying and discharging between both electrodes, and the semiconductor wafer 4 as an object to be processed is etched with the active species. For example, a frequency of about 400 kHz is used as the high frequency signal.
[0044]
In the light emission detection optical system 101, light emission 31 from plasma is imaged on the incident end 75 of the quartz optical fiber 50 by the quartz lens 32 through the quartz window 30. A certain point 74 on the wafer 4 in the plasma emission region and the incident end 75 of the quartz optical fiber 50 are in an imaging relationship.
[0045]
As shown in FIG. 2, a fiber bundle 76 having a rectangular cross-sectional shape corresponding to the plasma emission distribution observed from the quartz window 30 is formed at the incident end 75 of the quartz optical fiber 50 as a light receiving portion. As shown in FIG. 3, the fiber bundle 76 is divided into two regions, a central portion 77 and peripheral portions 78a and 78b. The central portion 77 is divided into the fiber 51 in FIG. 1, and the peripheral portions 78a and 78b are divided. Each is connected to a fiber 52.
[0046]
The fiber 51 is connected to the monochromator 53, and the fiber 52 is connected to the monochromator 58, and the emission spectrum component of a specific active species is selectively taken out and photoelectrically converted by photoelectric conversion elements 54 and 59 such as Photomaru. For example, when the silicon oxide film is etched using a fluorocarbon-based etching gas such as CF, the monochromator 53 has an emission spectrum from the reaction product CO, that is, a wavelength component of 219 nm or 483.5 nm. The monochromator 58 detects the emission spectrum from the intermediate product CF, that is, the 260 nm wavelength component. Of course, it is also possible to use an interference filter instead of the monochromator. In addition, by configuring the light emission detection optical system 101 as an imaging optical system, it is possible to detect light emission components in a limited area on the wafer, so that in-plane variation in the film thickness to be processed and in-plane of the etching rate. It is possible to reduce the dullness of the end point detection signal due to the variation.
[0047]
The light emission signal of the CO component having a wavelength of 219 nm photoelectrically converted by the photoelectric conversion element 54 is amplified by an amplifier 55 having a sufficiently wide band of about 2 MHz compared to the high frequency power for plasma excitation, and is sent to the signal processing circuit 56. FIG. 4A shows a light emission waveform 70a during etching. It can be seen that the light emission intensity change is repeated in a form in which the light emission process accompanying excitation / attenuation of active species in the plasma is superimposed on the basic period of 400 kHz synchronized with the high frequency power for plasma excitation. The repetition of the high-frequency voltage applied to the upper and lower electrodes is exactly 180 ° offset from each other because the repetition of the high-frequency voltage applied to the upper and lower electrodes is similar to the repetition of the high-peak having a cycle of 400 kHz and the repetition of a low-amplitude peak at 180 °. It is caused by being.
[0048]
FIG. 4B shows a light emission waveform 70b of the CO component immediately after the silicon oxide film is completely etched, that is, when the end point is reached. It can be seen that the amplitude of the high peak in FIG. 4A is greatly attenuated in synchronization with the decrease in the amount of reaction product generated, whereas the amplitude of the low peak hardly changes. That is, it can be seen that the light emission waveform of the CO component, which is an etching reaction product, contains a component that greatly attenuates at the end of etching and a component that hardly changes even when the same 400 kHz component is present. Therefore, if a lock-in amplifier is simply used, only this greatly changing component cannot be selectively extracted.
[0049]
Therefore, in the present embodiment, as shown in FIG. 1, in the sampling signal generation circuit 69, based on the 400 kHz high frequency signal from the signal generator 37, a rectangular shape having a pulse width Δt and a frequency of 400 kHz as shown in FIG. A sampling signal 72 consisting of a wave function is generated. The phase of the sampling signal 72 is adjusted by a desired amount in accordance with the light emission waveform by the phase shifter 65 in FIG. 1 and then sent to the signal processing circuit 56. In the phase adjustment method, for example, the light emission signal 70 from the amplifier 55 is observed with an oscilloscope 63, and as shown in FIGS. 4A, 4B, and 4C, a high peak component that changes greatly at the end point is sampled. The phase of the sampling signal 72 is adjusted.
[0050]
A line 64 from the oscilloscope 63 to the phase shifter 65 in FIG. 1 indicates an act of adjusting the phase of the sampling signal 72 while observing the waveform. In the figure, reference numeral 63 is not limited to an oscilloscope, but includes various means for detecting the phase of the light emission component to be selected from the light emission waveform 70a. For example, it may be a means for detecting only a high peak by a binarization circuit or the like to obtain the phase of the peak, or taking into account the positive / negative timing of the high frequency signal from the signal generator 37 and the delay time until plasma emission. Alternatively, a means for obtaining a high peak phase may be used. It is also possible to adjust the phase shift amount and capture the peak waveform at the timing slightly attenuated from the maximum amplitude, or capture the lower peak of the 400 kHz period.
[0051]
In any case, the phase shift amount is determined by sampling the emission waveform at the timing when the etching reaction is reflected most strongly, that is, when the amplitude change at the end point is maximized, depending on the process conditions such as the pressure in the processing chamber and the etching gas. It is desirable to set so that Similarly, the pulse width Δt is desirably set to a time width that maximizes the amplitude change at the end point. In the signal processing circuit 56, the light emission signal 70 from the amplifier 55 is multiplied by the sampling signal 72, and the light emission peak in the section corresponding to the pulse width Δt, that is, the high peak that greatly changes at the end point is selectively detected and output. The
[0052]
An output signal from the signal processing circuit 56 is sent to a low-pass filter 57 having a bandwidth of about 100 Hz, and a light emission signal 80 indicated by a solid line in FIG. 6 is obtained. The time tE at which the signal intensity rapidly decays corresponds to the etching end point. A broken line 79 is a light emission signal by a conventional DC component detection method. As in this example, it is more effective to selectively extract components synchronized with the etching reaction by sampling the plasma emission at the timing at which the etching reaction is reflected most strongly, that is, the timing at which the amplitude change at the end point is maximized. It can be seen that the signal change at the end point is about twice as large.
[0053]
According to this method, an improvement in the accuracy of detecting the etching end point in a fine pattern can be expected. However, in the field of semiconductors that are highly integrated into 256 Mbit DRAMs, and further to 1 Gbit DRAMs, there is no limit to the miniaturization of patterns. Particularly in the etching of contact holes, the area of the etched portion with respect to the total area of the wafer is 0.5. It is about to become less than%. In the etching of such a finer pattern, there is a possibility that even when the above method is used, it is difficult to detect the end point with high accuracy.
[0054]
Therefore, in this embodiment, as a major feature of the present invention, not only the reaction product CO but also the emission spectrum from the intermediate product CF detected by the monochromator 58 shown in FIG. In addition, the same signal processing as described above is performed and the two light emission signals are combined to realize highly accurate end point detection even for a finer pattern.
[0055]
A light emission signal of a CF component having a wavelength of 260 nm photoelectrically converted by the photoelectric conversion element 59 is amplified by an amplifier 60 having a bandwidth of about 2 MHz, which is wider than the high frequency power for plasma excitation, and is sent to the signal processing circuit 61. FIG. 5A shows a light emission waveform 71a during etching. It can be seen that the light emission intensity change is repeated in a form in which the light emission process accompanying excitation / attenuation of active species in the plasma is superimposed on the basic period of 400 kHz synchronized with the high frequency power for plasma excitation. Similar to the case of the CO component, the polarity of the high-frequency voltage applied to the upper and lower electrodes is similar to the case of the repetition of the peak having a slightly lower amplitude with a phase shift of 180 ° at 400 kHz. Is caused by the fact that they are exactly 180 ° apart from each other.
[0056]
FIG. 5B shows a light emission waveform 71b of the CF component immediately after the silicon oxide film is completely etched, that is, when the end point is reached. It can be seen that the consumption of the intermediate product CF decreases with the end of the etching, and the amplitude of the slightly higher peak in FIG. 5A greatly increases, whereas the amplitude of the lower peak hardly changes. That is, it can be seen that the light emission waveform of the CF component, which is an intermediate product of etching, includes a component that greatly increases at the end of etching and a component that hardly changes even when the same 400 kHz component is present. As in the case of the CO component, if the lock-in amplifier is simply used, only this greatly changing component cannot be selectively extracted.
[0057]
Therefore, as in the case of the CO component, as shown in FIG. 1, in the sampling signal generation circuit 69, based on the high frequency signal of 400 kHz from the signal generator 37, the pulse width Δt and the frequency of 400 kHz as shown in FIG. A sampling signal 73 consisting of a rectangular wave function is generated. The phase of the sampling signal 73 is adjusted by a desired amount according to the light emission waveform by the phase shifter 68 in FIG. 1 and then sent to the signal processing circuit 61. As in the case of the CO component, for example, the light emission signal 71 from the amplifier 60 is observed with an oscilloscope 66, and the phase adjustment method is greatly changed at the end point as shown in FIGS. 5 (a) (b) (c). The phase of the sampling signal 73 is adjusted so as to sample the peak component.
[0058]
A line 67 from the oscilloscope 66 to the phase shifter 68 in FIG. 1 indicates an act of adjusting the phase of the sampling signal 73 while observing the waveform. In the figure, reference numeral 68 is not limited to the oscilloscope, and includes various means for detecting the phase of the light emission component to be selected from the light emission waveform 71a. For example, it may be a means for detecting only a high peak with a binarization circuit or the like to obtain the phase of the peak, or taking into account the positive / negative timing of the high frequency signal from the signal generator 37 and the delay time until plasma emission. Alternatively, a means for obtaining a high peak phase may be used. It is also possible to adjust the phase shift amount and capture the peak waveform at the timing slightly attenuated from the maximum amplitude, or capture the lower peak of the 400 kHz period.
[0059]
In any case, it is desirable that the phase shift amount is set so that the emission waveform is sampled at the timing when the etching reaction is reflected most strongly, that is, at the timing when the amplitude change at the end point is maximized. Similarly, the pulse width Δt is desirably set to a time width that maximizes the amplitude change at the end point. In the signal processing circuit 61, the light emission signal 71 from the amplifier 60 is multiplied by the sampling signal 73, and a light emission peak in a section corresponding to the pulse width Δt, that is, a high peak that greatly changes at the end point is selectively detected and output. The
[0060]
An output signal from the signal processing circuit 61 is sent to a low pass filter 62 having a bandwidth of about 100 Hz, and a light emission signal 82 indicated by a solid line in FIG. 7 is obtained. The time tE at which the signal intensity increases rapidly corresponds to the etching end point. A broken line 81 is a light emission signal by a conventional DC component detection method. As in this example, it is more effective to selectively extract components synchronized with the etching reaction by sampling the plasma emission at the timing at which the etching reaction is reflected most strongly, that is, the timing at which the amplitude change at the end point is maximized. It can be seen that the signal change at the end point is about twice as large.
[0061]
The light emission signals of the reaction product CO and intermediate product CF output from the low-pass filters 57 and 62 are sent to the end point determination circuit 74, and division processing (CO light emission signal / CF light emission signal) or subtraction processing is performed between the two signals. (CO light emission signal−CF light emission signal) or the like is performed, and the signal change at the end point is emphasized. FIG. 8 shows a signal waveform 84 obtained by dividing the CO light emission signal 80 (FIG. 6) by the CF light emission signal 82 (FIG. 7). A broken line 83 is a division result between two light emission signals (broken line 79 in FIG. 6 and broken line 81 in FIG. 7) obtained by the conventional DC component detection method. It can be seen that the signal change at the end point is larger than in the case of the CO light emission signal 80 alone in FIG.
[0062]
Furthermore, even in the calculation processing between the emission signals obtained at the same two wavelengths, the signal change at the etching end point is about twice as much as that in the conventional DC component detection method when the signal processing of this embodiment is used. It turns out that it is big. In addition, the influence of fluctuations of the plasma itself and sudden fluctuations appear in both emission signals in the same way, and this can be offset by the arithmetic processing. It has been experimentally confirmed that the effect of canceling fluctuations and fluctuations of plasma using two light emission signals is larger when the signal processing of this embodiment is used than the conventional DC component detection method. This is also one of the major features of the present invention.
[0063]
In the end point determination circuit 74, the etching end point position is accurately determined by comparing the signal intensity at the signal change point, the primary differential value, the secondary differential value, or the like with a preset threshold value. For example, as shown in FIG. 8, a time tE when the emission intensity becomes equal to or less than the threshold value IE is determined as the end point. The threshold value IE is set according to apparatus conditions such as high-frequency power and pressure, and process conditions such as the film thickness, material, and etching gas of the film to be processed. When the end point is detected, the output of the power amplifier 38 is stopped based on the control signal 74c.
[0064]
In the case of this embodiment, the light emission of the reaction product or intermediate product is synchronized with the high frequency power for plasma excitation, but the synchronized component reflects the etching reaction, that is, changes greatly at the end of etching. Ingredients and components that hardly change are mixed. In the conventional DC component detection method, a component that does not change at the end point is also detected. In this embodiment, by selectively extracting only the amplitude component that greatly changes at the etching end point from the components synchronized with the high frequency power for plasma excitation, unnecessary components are removed and the signal change at the end point is expanded. Yes. As a result, not only is it difficult to be affected by so-called 1 / f noise such as gradual fluctuations in plasma emission, but it is also possible to accurately grasp the progress of etching in a fine pattern, enabling highly accurate end point detection. Become.
[0065]
Furthermore, by extracting similar amplitude components not only for reaction products but also for intermediate products, and performing processing such as division and subtraction between both signals, the signal change at the end point is further expanded and the SN ratio is improved. Furthermore, it is possible to cancel out sudden fluctuations in plasma, and it is possible to detect the end point with a finer pattern, which was difficult with the conventional method. As a result, film remaining due to insufficient etching, shift of the base film due to overetching, and damage are reduced. As a result, defects caused by etching during the photolithography process can be reduced, and high-quality semiconductor elements can be manufactured.
[0066]
In addition, since it is difficult to detect the end point of etching of minute contact holes with a pattern aperture ratio of 0.5% or less, the etch rate and remaining film thickness are measured during etching, and the remaining etching is time-controlled. It is finished with. In this way, extra prior work is performed during the etching, and the throughput of the etching process has been reduced. However, according to the present embodiment, the end point can always be detected with high accuracy, so that such a prior work is unnecessary, the productivity of the etching process is improved, and the entire production line can be automated.
[0067]
In addition, even when the light transmittance of the window is lowered due to the deposition of reaction products or the like, there is an effect that the stable detection operation time is increased as compared with the conventional method by increasing the signal change at the end point and improving the SN ratio.
[0068]
Further, if a means for preventing a decrease in light transmittance of the window is provided, the etching end point detection method according to the present invention can detect stably for a longer time. Here, as a means to prevent the light transmittance of the window from decreasing, a method of blowing gas near the surface of the inside of the window (processing chamber side) during the etching process or a transparent film attached to the inside of the window A method of replacing the film when the light transmittance decreases, a method of providing an orifice near the window in the processing chamber, and a method of detecting plasma emission through the orifice, and the like.
Further, by configuring the light emission detection optical system 101 as an imaging optical system, it is possible to detect light emission components in a limited area on the wafer, so that in-plane variation of the film thickness to be processed and in-plane of the etching rate. It is possible to reduce the dullness of the end point detection signal due to the variation.
[0069]
A second embodiment of the present invention will be described with reference to FIG. The basic configurations and functions of the light emission detection optical system 101 and the signal processing / determination / control system 202 are substantially the same as those in the first embodiment. The etching apparatus of the first embodiment is a parallel plate plasma etching apparatus in which the plasma excitation high frequency power supply and the ion acceleration high frequency power supply are shared and have the same frequency, but the etching apparatus of this embodiment has two frequencies. This is called a power supply system, and is different in that both have different power sources and different frequencies. A high frequency power having a frequency of 27.12 MHz is applied to the upper electrode 2 from a high frequency power source 85 for plasma excitation, and a high frequency power having a frequency of 800 kHz is applied to the lower electrode 3 from a high frequency power source 86 for accelerating ions. The etching reaction proceeds mainly in synchronization with the 800 kHz high frequency power applied to the lower electrode 3.
[0070]
In the light emission detection optical system 101, similarly to the first embodiment, the light emission 31 from the plasma is imaged by the quartz lens 32 through the quartz window 30 and guided to the signal processing / judgment / control system 202 by the quartz optical fiber 50. In the signal processing / determination / control system 202, the emission spectrum of the reaction product CO by the monochromator 53, the wavelength component of 219 nm or 483.5 nm is converted by the monochromator 53, and the intermediate product CF by the monochromator 58, as in the first embodiment. An emission spectrum and a wavelength component of 260 nm are respectively detected and photoelectrically converted by the photoelectric conversion elements 54 and 59.
[0071]
In the sampling signal generation circuit 69, the same pulse width Δt and frequency 800 kHz as shown in FIG. 4C and FIG. Sampling signals 72 and 73 comprising rectangular wave functions are generated. Subsequent signal processing is exactly the same as that of the first embodiment, and the signal processing circuits 56 and 61 determine the emission signal of the reaction product CO and the emission signal of the intermediate product CF based on the sampling signals 72 and 73, respectively. Only the amplitude component that reflects the etching reaction and changes greatly at the end point is selectively extracted.
[0072]
The light emission signal after passing through the low-pass filters 57 and 62 is the same as that shown in FIGS. 6 and 7, and the signal change at the end point is expanded as compared with the conventional DC component detection method. Further, by performing division processing on both signals in the end point determination circuit 87, as shown in FIG. 8, a light emission signal in which the signal change at the end point is further expanded is obtained.
[0073]
In the end point determination circuit 87, the etching end point position is accurately determined by comparing the signal intensity at the signal change point, the primary differential value, the secondary differential value, or the like with a preset threshold value. When the end point is detected, a control signal 87c is sent to a control circuit of an etching apparatus (not shown). Based on this, the outputs of the high frequency power supplies 85 and 86 are stopped and the etching is finished.
[0074]
In the case of the present embodiment, the light emission of the reaction product or intermediate product is synchronized with the high frequency power for ion acceleration, but some of the synchronized components reflect the etching reaction, that is, greatly change at the etching end point. Ingredients and components that hardly change are mixed. In this embodiment, by selectively extracting only the amplitude component that greatly changes at the etching end point from the components synchronized with the high frequency power for ion acceleration, unnecessary components are removed and the signal change at the end point is expanded. Yes. As a result, as in the first embodiment, not only is it less susceptible to so-called 1 / f noise such as gradual fluctuations in plasma emission, but it is also possible to accurately grasp the progress of etching in a fine pattern, High-precision end point detection is possible.
[0075]
Furthermore, by extracting similar amplitude components not only for reaction products but also for intermediate products, and performing processing such as division and subtraction between both signals, the signal change at the end point is further expanded and the SN ratio is improved. In addition, it is possible to cancel out sudden fluctuations in plasma, and it is possible to detect the end point with a finer pattern, which was difficult with the conventional method. As a result, film remaining due to insufficient etching, shift of the base film due to overetching, and damage are reduced. As a result, defects caused by etching during the photolithography process can be reduced, and high-quality semiconductor elements can be manufactured.
[0076]
In addition, since it is difficult to detect the end point of etching of minute contact holes with a pattern aperture ratio of 0.5% or less, the etch rate and remaining film thickness are measured during etching, and the remaining etching is time-controlled. It is finished with. In this way, extra prior work is performed during the etching, and the throughput of the etching process has been reduced. However, according to the present embodiment, the end point can always be detected with high accuracy, so that such a prior work is unnecessary, the productivity of the etching process is improved, and the entire production line can be automated.
[0077]
In addition, even when the transmittance of the window is lowered due to the deposition of reaction products or the like, there is an effect that the stable detection operation time is increased as compared with the conventional method by increasing the signal change at the end point and improving the SN ratio.
[0078]
Similarly to the first embodiment, by configuring the light emission detection optical system 101 as an imaging optical system, it is possible to detect light emission components in a limited area on the wafer, so that the surface of the film thickness to be processed It is possible to reduce the dullness of the end point detection signal due to the in-plane variation and the in-plane variation of the etching rate.
[0079]
A third embodiment of the present invention will be described with reference to FIG. As in the second embodiment, the etching apparatus is a parallel plate type plasma etching apparatus. The upper electrode 2 receives high-frequency power of 27.12 MHz from the plasma excitation high-frequency power source 85, and the lower electrode 3 receives ions. A high frequency power having a frequency of 800 kHz is applied from the acceleration high frequency power supply 86. The etching reaction proceeds mainly in synchronization with the 800 kHz high frequency power applied to the lower electrode 3.
[0080]
In the first and second embodiments, the light emission detection optical system is configured to form an image at a certain point on the wafer. However, in the light emission detection optical system 102 of this embodiment, the light emission 20 from the plasma is galvano-sensitive. After being reflected by a scanning mirror such as the mirror 23, an image is formed on the incident end 25 of the quartz optical fiber 50 by the quartz lens 24. A certain point 21 on the wafer 4 in the plasma emission region and the incident end 25 of the quartz optical fiber 50 are in an imaging relationship. By rotating and scanning the galvanometer mirror 23 at a high speed by the drive system 22, light emission from a plurality of points (black circles) on the wafer 4 can be sequentially imaged on the incident end 25 of the quartz optical fiber 50.
[0081]
That is, light emission at a plurality of points on the wafer can be detected almost simultaneously. The configuration and function of the light emission detection optical system 102 and the signal processing / judgment / control system 203 are that the drive control of the galvano mirror 23 and the rearrangement control of the light emission signals at each point obtained in time series are added. Except for this, it is equivalent to the second embodiment. The light emission detected by the quartz optical fiber 50 is subjected to the same signal processing as in the first and second embodiments in the signal processing / determination / control system 203, and finally in the end point determination / control circuit 88. In synchronization with the driving of the galvanometer mirror 23, the etching end point at each point on the wafer is detected. For example, when the latest end point is detected, the outputs of the high frequency power supplies 85 and 86 are stopped based on the control signal 88c.
[0082]
According to this embodiment, not only the same effects as those of the first and second embodiments can be obtained, but also plasma emission at any one point or a plurality of points on the wafer is measured almost simultaneously. By selecting a detection signal at a position that more accurately reflects the etching reaction and executing the end point determination, the end point determination accuracy in the minute opening pattern is improved. As a result, film remaining due to insufficient etching, shift of the base film due to overetching, and damage are reduced. As a result, defects caused by etching during the photolithography process can be reduced, and high-quality semiconductor elements can be manufactured. In addition, it is possible to diagnose the in-plane variation of plasma density, variation of film thickness to be processed, variation in etching rate, etc. from the variation in emission signal intensity at each point and variation in end point time, and feedback to the apparatus based on the results. .
[0083]
A fourth embodiment of the present invention will be described with reference to FIG. Similar to the first embodiment, the etching apparatus is a parallel plate type plasma etching apparatus, and the plasma excitation high frequency power source and the ion acceleration high frequency power source are shared, and the frequency is 400 kHz. The configuration and function of the light emission detection optical system 101 are exactly the same as those of the first embodiment, and the signal processing / determination / control system 204 also has the first configuration and function from the quartz optical fiber 50 to the end point determination circuit 89. The description is omitted because it is exactly the same as the embodiment.
[0084]
In this embodiment, the output of the high frequency power supply (power amplifier) is not stopped based on the detected etching end point as in the first to third embodiments, but the end point time is the film thickness to be processed, pressure, etching It is set in advance from process conditions such as gas and etching rate and apparatus conditions. The purpose of this embodiment is to manage over-etching time for each wafer and detect abnormalities such as film thickness and etching rate by constantly observing the difference between the measured etching end point and the set etching time. . Therefore, the signal processing / determination / control system 204 of this embodiment has a configuration in which an end point control unit 91 and an end point management unit 93 are added to the first signal processing / determination / control system 201.
[0085]
Details will be described below. The end point control unit 91 sets the etching time tEP based on the process / equipment conditions 92 such as the film thickness to be processed, the pressure, the etching gas, and the etching rate, and sends the control signal 91c to the power amplifier 38 to output the high frequency power. Etching is started. At the same time, the set etching time information 92 a is sent to the end point management unit 93. When the set etching time comes, the output of the power amplifier 38 is stopped based on the control signal 91c. The end point determination circuit 89 obtains end points ta, tb, and tc from the light emission signals 96 to 99 detected for each wafer and sends the end point time information 90 to the end point management unit 93 as shown in FIG.
[0086]
In the end point management unit 93, referring to the processed film thickness information / etching rate information 94 for each wafer or lot, as shown in FIG. 12, the set etching time tEP and the actual etching end time ta for each wafer are shown. , Tb, and tc are compared to determine whether there is an abnormality. For example, ΔtEP is set as an allowable limit of the overetching time with respect to the set etching time tEP. The overetching time Δtc for the end point tc of the light emission signal 98 is within the allowable range, but the overetching times Δta and Δtb for the light emission signals 96 and 97 exceed the allowable range. In this case, the abnormality from the end point management unit 93 is, for example, blinking of an alarm lamp, transmission of an alarm sound by an alarm buzzer, display of an abnormality on the display screen, or alarm signal to an external control means or an external device. An outgoing call is reported.
[0087]
The waveform 99 does not reach the end point within the set etching time tEP. In this case also, an abnormality is reported. Wafers corresponding to the waveforms 96 and 97 are excluded from the line, the state of the underlying film is checked, and the wafer corresponding to the waveform 99 is subjected to additional etching after the remaining film is measured.
[0088]
Further, the end point management unit 93 obtains a predicted value of the end point for each wafer or each lot based on the processed film thickness information / etching rate information 94, and compares the predicted value with the actual measurement values ta, tb, tc. When the difference exceeds a certain allowable range, an abnormality is reported as a sudden film thickness abnormality or etch rate abnormality has occurred.
[0089]
According to the present embodiment, as in the first and second embodiments, since it is possible to detect the end point with high accuracy in the etching of a fine pattern, it is possible to manage overetching time, film thickness, and etching rate for each wafer. And the like can be detected. As a result, film remaining due to insufficient etching, shift of the base film due to overetching, and damage are reduced. As a result, defects caused by etching during the photolithography process can be reduced, and high-quality semiconductor elements can be manufactured.
[0090]
A fifth embodiment of the present invention will be described with reference to FIG. In this embodiment, an etching end point detection apparatus comprising the light emission detection optical systems 101 to 102 and the signal processing / judgment / control systems 201 to 204 based on the four embodiments described above is introduced into the photolithography process of the semiconductor manufacturing line. . As shown in FIG. 13, first, a film to be processed such as a silicon oxide film is formed on a semiconductor wafer by a film deposition apparatus 301.
[0091]
After the film thickness measurement device 302 measures the film thickness at a plurality of points on the wafer, the resist coating device 303 applies a resist. A desired circuit pattern on the reticle or mask is transferred by the exposure device 304. From the exposed semiconductor wafer, the developing unit 305 removes the resist portion corresponding to the transfer pattern. In the etching apparatus 306, the film to be processed in the resist removing portion is etched using the resist pattern as a mask. The emission spectra of reaction products and intermediate products generated during etching are detected by the emission detection optical systems 101 to 102, and when the etching end point is detected from the emission signals by the signal processing / judgment / control systems 201 to 204, the control signal Based on 200c, the output of the high frequency power source of the etching apparatus 306 is stopped. The semiconductor wafer after completion of the etching is sent to the ashing device 307, and after the resist is removed, it is cleaned by the cleaning device 308.
[0092]
According to the present embodiment, the etching end point detection apparatus comprising the light emission detection optical systems 101 to 102 and the signal processing / judgment / control systems 201 to 204 based on the above-described embodiment is used as the etching apparatus in the photolithography process. As a result, the etching end point detection accuracy is improved, and the film residue due to insufficient etching, the shift of the base film due to overetching, and damage are reduced. As a result, defects caused by etching during the photolithography process can be reduced, and high-quality semiconductor elements can be manufactured.
[0093]
In addition, the etching of minute contact holes with a pattern aperture ratio of 0.5% or less is currently difficult to detect the end point. Therefore, the etching rate and the remaining film thickness are measured during the etching, and the remaining etching is time-controlled. It is finished with. In this way, extra prior work is performed during the etching, and the throughput of the etching process has been reduced. However, according to the present embodiment, the end point can always be detected with high accuracy, so that such a prior work is unnecessary, the productivity of the etching process is improved, and the entire production line can be automated.
[0094]
Further, by combining the fourth embodiment and the present embodiment and observing the fluctuation of the detection waveform and the end point time shown in FIG. 12, an increase in film thickness variation, etching rate fluctuation, or erroneous setting of etching conditions, Furthermore, it is possible to detect overexposure and underexposure in the exposure / development process. As a result, defects in the film forming apparatus 301, the etching apparatus 306, the exposure apparatus 304, and the developing apparatus 305 can be found at an early stage, as indicated by lines 311, 312, 313, and 314 in FIG. Since measures can be taken at an early stage, it is possible to prevent the occurrence of defective products and improve the yield.
[0095]
In the above embodiment, the high frequency power for plasma excitation is 400 kHz or 27.12 MHz and the high frequency power for ion acceleration is 400 kHz or 800 kHz. However, the present invention is not limited to these frequencies. If the frequency is in a band where periodic plasma emission can be observed, it can be applied to other frequencies such as 13.56 MHz, and not only the components synchronized with these frequencies but also at the time of detection. It is also possible to detect an integral multiple of the component.
[0096]
In the above embodiment, the two wavelengths are 219 nm and 260 nm. However, these wavelengths are merely examples, and the present invention is not limited to this. Any wavelength is applicable as long as it reflects the etching reaction, that is, the wavelength at which the change appears at the end of etching.
[0097]
Moreover, in the above Example, although the end point is detected from the light emission signal of two wavelengths corresponding to a reaction product and an intermediate product, this invention is not limited to two wavelengths, Three or more Applicable to wavelength. If a sufficient signal change is detected at the end point, only one wavelength may be used.
[0098]
In the above embodiment, the signal processing for extracting the component reflecting the etching reaction is performed on both of the emission signals of the two wavelengths, but the signal processing is performed on only one of them, and the other is the conventional DC component. It is also possible to apply a detection method.
[0099]
In the above embodiments, the oxide film etching has been described as an example. However, the present invention can be applied to etching of a metal such as aluminum, polysilicon, silicon nitride (Si3N4), or the like.
In the above embodiment, the sampling signal of the rectangular wave function is used as a method for selectively extracting only the component reflecting the etching reaction from the light emission signal. However, the present invention is not limited to this. It is also possible to use a sampling signal comprising an impulse train. It is also possible to sample only the amplitude of the modulation component of the light emission signal (AC component) after removing the direct current component from the light emission signal with a high-pass filter or the like.
[0100]
In the above embodiments, the etching apparatus is a parallel plate type plasma etching apparatus. However, the present invention is not limited to this, and various etching apparatuses such as an ECR etching apparatus or a microwave etching apparatus may be used. It goes without saying that is also applicable.
[0101]
Furthermore, in the above-described embodiment, the application example of the present invention to the etching apparatus has been described. However, the present invention is not limited to the end point detection of the etching process or the plasma emission measurement, but the emission spectrum as the plasma process proceeds. The present invention can be applied to end point detection or plasma emission measurement of various plasma processing apparatuses whose intensity changes, for example, a sputtering processing apparatus or a plasma CVD apparatus. Further, the object to be processed is not limited to a semiconductor wafer, but can be applied to various elements and materials that are subjected to plasma treatment in the manufacturing process, such as a substrate for a liquid crystal display device and a semiconductor laser element.
[0102]
【The invention's effect】
According to the present invention, only the amplitude component that strongly reflects the etching reaction, that is, greatly changes at the end of etching, is selectively extracted from a plurality of light emission signals such as reaction products and intermediate products, and divided between the plurality of signals. By executing processing such as subtraction, unnecessary components can be removed and signal changes at the end point can be greatly expanded. As a result, it is possible to clearly capture a weak signal change at the end point in a finer pattern, which was difficult with the conventional method, and to determine the end point with high accuracy.
[0103]
Further, according to the present invention, not only is it not easily affected by so-called 1 / f noise such as gradual fluctuations in plasma emission, but also an effect of improving the SN ratio and further canceling out sudden fluctuations in plasma can be realized. Have.
[0104]
Furthermore, according to the present invention, the film residue due to insufficient etching and the shift of the base film due to overetching are reduced. As a result, defects due to etching during the photolithography process can be reduced, and it is possible to produce a high-quality semiconductor element.
[0105]
Further, according to the present invention, the etching of minute contact holes with a pattern aperture ratio of 0.5% or less is currently difficult to detect the end point, so the etch rate and the remaining film thickness are measured during the etching, The remaining etching is terminated by time management. In this way, extra prior work is performed during the etching, and the throughput of the etching process has been reduced. However, according to the present embodiment, the end point can always be detected with high accuracy, so that such a prior work is unnecessary, the productivity of the etching process is improved, and the entire production line can be automated.
[0106]
In addition, according to the present invention, even when the transmittance of the window is lowered due to deposition of reaction products, the stable detection operation time is increased as compared with the conventional method by increasing the signal change at the end point and improving the SN ratio. There is an effect.
[0107]
In addition, by configuring the light emission detection optical system as an imaging optical system, it is possible to detect the light emission components in a limited area on the wafer, so in-plane variation in the film thickness to be processed and in-plane variation in the etching rate It is possible to reduce the dullness of the end point detection signal due to.
[Brief description of the drawings]
FIG. 1 is a diagram showing an etching apparatus and an etching end point detection apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a shape of an incident end of a quartz optical fiber.
FIG. 3 is a diagram showing a cross-sectional shape of a quartz optical fiber bundle.
FIG. 4 is a diagram showing a light emission waveform (a) of a CO component having a wavelength of 219 nm during etching, a light emission waveform (b) immediately after reaching the end point, and a waveform (c) of a sampling signal made up of a rectangular wave function. is there.
FIG. 5 is a diagram showing a light emission waveform (a) of a CF component having a wavelength of 260 nm during etching, a light emission waveform (b) immediately after reaching the end point, and a waveform (c) of a sampling signal composed of a rectangular wave function. is there.
FIG. 6 is a diagram showing light emission signals of CO components after signal processing (solid line) and the conventional method (dashed line).
FIG. 7 is a diagram showing light emission signals of CF components after signal processing (solid line) and a conventional method (dashed line).
FIG. 8 is a diagram showing a signal waveform obtained by dividing a CO light emission signal after signal processing (solid line) by a CF light emission signal, and a signal waveform in a conventional method (dashed line).
FIG. 9 is a diagram showing an etching apparatus and an etching end point detection apparatus in a second embodiment of the present invention.
FIG. 10 is a diagram showing an etching apparatus and an etching end point detection apparatus in a third embodiment of the present invention.
FIG. 11 is a diagram showing an etching apparatus and an etching end point detection apparatus according to a fourth embodiment of the present invention.
FIG. 12 is a diagram showing a light emission signal detected for each wafer.
FIG. 13 is a diagram showing a photolithography process of a semiconductor manufacturing line in which an etching end point detection device is introduced in the fifth embodiment of the present invention.
FIG. 14 is a diagram showing a plasma etching apparatus and a conventional etching end point detection apparatus.
FIG. 15 is a diagram showing a change with time of emission intensity of active species by a conventional etching end point detector.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Processing chamber, 2 ... Upper electrode, 3 ... Lower electrode, 4 ... Semiconductor wafer, 5, 85, 86 ... High frequency power supply, 6 ... Plasma, 7 ... Window, 8, 20, 31 ... Plasma emission, 9, 53, 58 ... Spectrum (monochromator), 10 ... Active species luminescent component, 11, 54, 59 ... Photoelectric conversion element, 12, 55, 60 ... Amplifier, 13 ... End point determination unit, 14 ... Power supply control device, 15, 16 ... Time waveform of active species emission intensity, 23 ... Galvano mirror, 24, 32 ... Quartz lens, 30 ... Quartz window, 37 ... Signal generator, 38 ... Power amplifier, 39 ... Distributor, 50 ... Quartz optical fiber, 56, 61 ... Signal processing circuit 57, 62 ... Low-pass filter, 69 ... Sampling signal generation circuit, 65, 68 ... Phase shifter, 76 ... Fiber bundle, 70 ... Light emission waveform of CO component, 71 ... Light emission wave of CF component 72, 73 ... Sampling signal, 74, 87, 89 ... End point determination circuit, 80 ... Light emission signal of CO component after signal processing, 82 ... Light emission signal of CF component after signal processing, 84, 96, 97, 98, 99 ... Signal waveform after processing of the CO emission signal / CF emission signal, 88 ... End point determination / control circuit, 91 ... End point control unit, 93 ... End point management unit, 101, 102 ... Emission detection optical system, 201, 202, 203, 204: Signal processing / determination / control system 301: Film forming device 302: Film thickness measuring device 303 ... Resist coating device 304: Exposure device 305 ... Developing device 306 Etching device 307 Ashing device 308 ... cleaning equipment.

Claims (10)

Plasma is applied to the substrate to be processed placed on the lower electrode while applying high-frequency power for ion acceleration to the lower electrode on which the substrate to be processed is applied in a state where plasma is generated by applying the plasma excitation high frequency power A method of detecting an end point of processing of the substrate to be processed when etching is performed, detecting light having a predetermined wavelength of light emission of the plasma during processing of the substrate to be processed, and detecting the predetermined wavelength of the detected wavelength A signal component that changes in accordance with the progress of the etching process by the plasma is extracted from the light emission signal at a frequency synchronized with the frequency of the high frequency power for ion acceleration applied to the lower electrode, or an integer multiple thereof, endpoint detection method for a plasma treatment, characterized in Rukoto issuing detects the end point of the etching process by the plasma on the basis of a change in the intensity of the signal component. 2. The plasma processing end point detection method according to claim 1, wherein the light having a predetermined wavelength of light emission of the plasma during the etching process to be detected is a light emission signal of a reaction product generated by the etching process by the plasma. . 2. The plasma according to claim 1, wherein the light having a predetermined wavelength of light emission of the plasma during the etching process to be detected is a light emission signal of a reaction gas or an intermediate product used in the etching process by the plasma. Processing end point detection method. Plasma is applied to the substrate to be processed placed on the lower electrode while applying high-frequency power for ion acceleration to the lower electrode on which the substrate to be processed is applied in a state where plasma is generated by applying high frequency power for plasma excitation to the upper electrode. a method of etching, the light emitting intensity with the light and the etching wavelength component emission intensity increases with the etching out of the plasma emission in the processing substrate to an etching process is reduced The frequency component of the ion acceleration high-frequency power applied to the lower electrode is separately detected and detected, and the wavelength component light that increases the emission intensity and the wavelength component light that decreases the emission intensity. or by extraction with a period synchronous with the integral multiple thereof, the wavelength component light emission intensity is decreased wavelength component emission intensity increases to the extracted intensity of the light Endpoint detection method for a plasma treatment, characterized in that detecting the end point of the etching process by the plasma on the basis of reduction. A circuit pattern on a reticle or a mask is formed by forming a film to be processed on the substrate to be processed, applying a resist on the substrate to be processed on which the film to be processed is formed, and applying the resist on the substrate to be processed and exposing the resist. The resist to which the circuit pattern was transferred by exposure is developed to form a resist pattern on the substrate to be processed, thereby exposing a part of the film to be processed and plasma etching using the resist pattern as a mask. The film to be processed in which the part is exposed is removed by processing, the substrate to be processed after the plasma etching process is ashed to remove the resist on the substrate to be processed, and the resist to which the resist has been removed is removed. A method of manufacturing a semiconductor device for cleaning a processing substrate,
In the step of removing the film to be processed in which the part is exposed by plasma etching using the resist pattern as a mask,
Plasma is applied to the substrate to be processed placed on the lower electrode while applying high-frequency power for ion acceleration to the lower electrode on which the substrate to be processed is applied in a state where plasma is generated by applying high frequency power for plasma excitation to the upper electrode. Etching is performed, and light having a predetermined wavelength of light emission of the plasma during the plasma etching process is detected on the substrate to be processed, and the etching process by the plasma proceeds from the detected light emission signal of the predetermined wavelength. The signal component that changes in response is extracted at a frequency synchronized with the frequency of the ion acceleration high-frequency power applied to the lower electrode or an integer multiple thereof, and the etching process using the plasma based on the change in the intensity of the extracted signal component detecting the end point, it terminated children etching treatment of the substrate to be processed on the basis of the end point of the etching treatment by the plasma the detected The method of manufacturing a semiconductor device according to claim. 6. The method of manufacturing a semiconductor device according to claim 5 , wherein the light having a predetermined wavelength of the light emission of the plasma detected during the plasma etching process is a light emission signal of a reaction product generated by the etching process using the plasma . 6. The semiconductor according to claim 5 , wherein the light having a predetermined wavelength of the light emission of the plasma detected during the plasma etching process is a light emission signal of a reaction gas or an intermediate product used in the etching process by the plasma. Device manufacturing method. A circuit pattern on a reticle or a mask is formed by forming a film to be processed on the substrate to be processed, applying a resist on the substrate to be processed on which the film to be processed is formed, and applying the resist on the substrate to be processed and exposing the resist. The resist to which the circuit pattern was transferred by exposure is developed to form a resist pattern on the substrate to be processed, thereby exposing a part of the film to be processed and plasma etching using the resist pattern as a mask. The film to be processed in which the part is exposed is removed by processing, the substrate to be processed after the plasma etching process is ashed to remove the resist on the substrate to be processed, and the resist to which the resist has been removed is removed. A method of manufacturing a semiconductor device for cleaning a processing substrate,
In the step of removing the film to be processed in which the part is exposed by plasma etching using the resist pattern as a mask,
Plasma is applied to the substrate to be processed placed on the lower electrode while applying high-frequency power for ion acceleration to the lower electrode on which the substrate to be processed is applied in a state where plasma is generated by applying high frequency power for plasma excitation to the upper electrode. etching treatment, emission intensity decreases with the該被substrate to light and the plasma etching wavelength component emission intensity with the plasma etching process from the light emission of the plasma in the plasma etching process is increased Separately detecting the light of the wavelength component, and the frequency of the ion acceleration high-frequency power applied to the lower electrode, respectively, the light of the wavelength component that increases the emission intensity and the light of the wavelength component that decreases the emission intensity , or by extraction with a period synchronous with its integral multiple, the optical wavelength components of light emission intensity is decreased wavelength component emission intensity increases to the extracted Based on the change in intensity to detect the end point of the etching process by the plasma, a method of manufacturing a semiconductor device, which comprises terminating the plasma etching process of the substrate to be processed on the basis of the end point of the etching treatment by the plasma the detected . Of the plasma emission detected during the etching process, the wavelength component light whose emission intensity increases with the etching process and the wavelength component light whose emission intensity decreases with the etching process are respectively etched by the plasma. 9. The method of manufacturing a semiconductor device according to claim 8 , wherein the signal is a light emission signal of a reaction product generated by the step . Of the plasma emission detected during the etching process, the wavelength component light whose emission intensity increases with the etching process and the wavelength component light whose emission intensity decreases with the etching process are respectively etched by the plasma. 9. The method of manufacturing a semiconductor device according to claim 8 , wherein the signal is a light emission signal of a reaction gas or an intermediate product used in the semiconductor device.

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