Plasma processing system

Abstract

To provide a technology for suppressing influence of an electron density on a light emission intensity inside a plasma processing chamber.SOLUTION: A plasma processing system comprises: a plasma processing chamber that houses a substrate therein; a light emission intensity measurement section that measures, inside the plasma processing chamber, a light emission intensity of a wavelength caused by a by-product or processed gas in plasma processing; an electron density measurement section that measures an electron density inside the plasma processing chamber; and a control section that determines an endpoint of the plasma processing when variation in the electron density measured by the electron density measurement section is small and variation in the light emission intensity measured by the light emission intensity measurement section is large.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a plasma processing system.

Background Art

[0002] For example, Patent Document 1 discloses an etching apparatus including a substrate electrode that applies high-frequency power to a substrate to be etched and a source electrode that generates plasma supplied onto the substrate electrode. Patent Document 1 discloses that the etching apparatus is provided with electron density control means for controlling the high-frequency power applied to the source electrode so that the electron density in the plasma supplied onto the substrate electrode becomes a predetermined set value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for suppressing the influence of electron density on the emission intensity inside a plasma processing chamber.

Means for Solving the Problems

[0005] According to one aspect of the present disclosure, there is provided a plasma processing system including a plasma processing chamber that houses a substrate therein, an emission intensity measurement unit that measures the emission intensity of a wavelength caused by a by-product or a processing gas in plasma processing inside the plasma processing chamber, an electron density measurement unit that measures the electron density inside the plasma processing chamber, and a control unit that determines that it is the end point in the plasma processing when a change in the electron density measured by the electron density measurement unit is small and a change in the emission intensity measured by the emission intensity measurement unit is large.

Effect of the Invention

[0006] The present disclosure provides a technique for suppressing the influence of electron density on the emission intensity inside a plasma processing chamber.

Brief Description of the Drawings

[0007]

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Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments for implementing the present disclosure will be described with reference to the drawings. In the present specification and drawings, for substantially the same configurations, the same reference numerals are given to omit redundant descriptions. Note that, for ease of understanding, the scales of the respective parts in the drawings may be different from the actual ones. Deviations within a range that does not impair the effects of the embodiments are allowed in directions such as parallel, right angle, orthogonal, horizontal, vertical, up and down, left and right. The shape of the corners is not limited to a right angle and may be rounded. Parallel, right angle, orthogonal, horizontal, and vertical may include substantially parallel, substantially right angle, substantially orthogonal, substantially horizontal, and substantially vertical.

[0009] <Plasma Processing System> Hereinafter, a configuration example of the plasma processing system will be described. FIG. 1 is a diagram for explaining the configuration of a plasma processing system S which is an example of the plasma processing system according to the present embodiment.

[0010] The plasma processing system S includes a capacitively coupled plasma processing apparatus 1 and a control unit 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power source 30, an exhaust system 40, a light emission intensity measurement unit 50, and an electron density measurement unit 60. Further, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support unit 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas discharge port for discharging gas from the plasma processing space. The side wall 10a is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the plasma processing chamber 10 housing.

[0011] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W and an annular region (ring support surface) 111b for supporting the ring assembly 112. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is disposed on the central region 111a of the main body portion 111, and the ring assembly 112 is disposed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. In one embodiment, the main body portion 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has the substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Also, although not shown, the substrate support portion 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path. Further, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0012] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Further, the shower head 13 includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. Note that the gas introduction part may include, in addition to the shower head 13, one or more side gas injectors (SGI) attached to one or a plurality of openings formed in the side wall 10a.

[0013] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas from the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Further, the gas supply unit 20 may include one or more flow modulation devices that modulate or pulse the flow rate of at least one processing gas.

[0014] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive member of the substrate support portion 11 and / or the conductive member of the shower head 13. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, the RF power supply 31 can function as at least a part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. Further, by supplying a bias RF signal to the conductive member of the substrate support portion 11, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0015] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to the conductive member of the substrate support unit 11 and / or the conductive member of the shower head 13 via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 13 MHz to 150 MHz. In one embodiment, the first RF generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive member of the substrate support unit 11 and / or the conductive member of the shower head 13. The second RF generation unit 31b is coupled to the conductive member of the substrate support unit 11 via at least one impedance matching circuit, and is configured to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a frequency lower than that of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In one embodiment, the second RF generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to the conductive member of the substrate support unit 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0016] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 32a is connected to a conductive member of the substrate support unit 11 and is configured to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support unit 11. In one embodiment, the first DC signal may be applied to other electrodes such as the electrodes in the electrostatic chuck. In one embodiment, the second DC generation unit 32b is connected to a conductive member of the shower head 13 and is configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the shower head 13. In various embodiments, at least one of the first and second DC signals may be pulsed. Note that the first and second DC generation units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0017] The exhaust system 40 can be connected to, for example, a gas outlet 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0018] The light emission intensity measurement unit 50 measures the light emission intensity of the plasma in the plasma processing chamber 10. The light emission intensity measurement unit 50 measures the light emission intensity of the wavelength caused by the by-products or the processing gas in the plasma processing inside the plasma processing chamber 10. The light emission intensity measurement unit 50 includes, for example, a spectroscope. The light emission intensity measurement unit 50 measures the light emission intensity of light of a predetermined wavelength in order to measure the light emission intensity of the atom or molecule to be measured. The light emission intensity measurement unit 50 is installed, for example, on the side wall 10a in the plasma processing chamber 10. The light emission intensity measurement unit 50 measures the light emission intensity of the plasma inside the plasma processing chamber 10 through a window provided on the side wall 10a in the plasma processing chamber 10.

[0019] The electron density measurement unit 60 measures the electron density inside the plasma processing chamber 10. The plasma processing apparatus 1 includes a VI probe as the electron density measurement unit 60 that measures the current value and voltage value of the power supplied from the power supply 30 to the plasma processing chamber 10. The current value and voltage value of the power supplied from the power supply 30 to the plasma processing chamber 10 are correlated with the electron density of the plasma inside the plasma processing chamber 10. Therefore, the electron density measurement unit 60 can estimate the electron density of the plasma based on the measurement results by the electron density measurement unit 60 by using the VI probe.

[0020] Note that in the electron density measurement unit 60, not only the case of measuring the electron density itself inside the plasma processing chamber 10, for example, an electron density correlation parameter correlated with the electron density may be measured. Also, in the electron density measurement unit 60, the measurement of the electron density is not limited to the measurement by the VI probe. In the electron density measurement unit 60, the measurement of the electron density inside the plasma processing chamber 10 may be, for example, a measurement using a measuring instrument capable of measuring the plasma density. In the electron density measurement unit 60, the measurement of the electron density inside the plasma processing chamber 10 may be, for example, a measurement using an emission spectrometer, a microwave interferometer, or a plasma absorption probe.

[0021] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes described in the present disclosure. The control unit 2 can be configured to control each element of the plasma processing apparatus 1 so as to execute the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 can be configured to perform various control operations based on a program stored in the storage unit 2a2. The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0022] <Plasma Processing System According to This Embodiment> The plasma processing system according to this embodiment will be described. The plasma processing system according to this embodiment includes a plasma processing chamber that houses a substrate therein, and a light emission intensity measurement unit that measures the light emission intensity of a wavelength caused by a by-product or a processing gas in the plasma processing inside the plasma processing chamber. Further, the plasma processing system according to this embodiment includes an electron density measurement unit that measures the electron density inside the plasma processing chamber. Furthermore, the plasma processing system according to this embodiment includes a control unit that determines an end point in the plasma processing. The control unit determines that it is the end point in the plasma processing when the change in the electron density measured by the electron density measurement unit is small and the change in the light emission intensity measured by the light emission intensity measurement unit is large.

[0023] Next, an explanation will be given from another perspective. The plasma processing system according to the present embodiment includes a plasma processing chamber that houses a substrate therein, a light emission intensity measurement unit that measures the light emission intensity inside the plasma processing chamber, and an electron density measurement unit that measures the electron density inside the plasma processing chamber. Further, the plasma processing system according to the present embodiment includes a control unit that corrects the light emission intensity measured by the light emission intensity measurement unit using the electron density measured by the electron density measurement unit and a correction coefficient between the light emission intensity and the electron density calculated in advance, and calculates a corrected light emission intensity.

[0024] The plasma processing system monitors the light emission of by-products and etchant gas generated from the target film in order to detect the switching of the processing film on the processing substrate. Then, the plasma processing system detects the film switching based on the monitored light emission state. The plasma processing system stops the process at the timing of the detected film switching. As described above, detecting the end point of the process is called end point detection (EPD).

[0025] The light emission of the plasma in the plasma processing chamber changes not only due to the light emission caused by by-products and etchant gas generated from the target film, but also due to changes in the electron density caused by state fluctuations in the plasma processing chamber. The fluctuations caused by the electron density become noise in end point detection.

[0026] In order to reduce the influence of the electron density, for example, it is conceivable to smooth it over a long period of time. When smoothing is performed, a delay may occur in the processing. When a delay occurs in the processing, it may affect the CD (Critical Dimension), reduce the throughput, or damage the underlying film.

[0027] A specific example will be described. FIG. 2 is a diagram for explaining the processing in a plasma processing system S which is an example of the plasma processing apparatus according to the present embodiment. The horizontal axis in FIG. 2 conceptually represents time, and the vertical axis represents the light emission intensity.

[0028] In FIG. 2, during period PRD1, assume that the plasma inside the plasma processing chamber 10 is stable under certain defined conditions. When the plasma inside the plasma processing chamber 10 is stable under certain defined conditions, as shown in period PRD1, the emission intensity of the plasma becomes a certain intensity.

[0029] Next, a case where the electron density in the plasma changes from period PRD1 to period PRD2 will be described. For example, in the plasma processing system S, when the voltage value in the high-frequency power (RF power) supplied from the power supply 30 changes, or the addition amount of argon gas changes, the electron density in the plasma fluctuates. When the electron density in the plasma fluctuates, as shown by arrow A1 in FIG. 2, the emission intensity fluctuates rapidly. Then, as shown in period PRD2, the emission intensity stabilizes at a certain value.

[0030] Next, assume that etching is being performed on the process film during period PRD3. When etching is being performed during period PRD3, the gas density such as by-products generated from the target film and etchant gas fluctuates. When the gas density fluctuates, as shown by arrow A2 in FIG. 2, the emission intensity gradually decreases. In the example of FIG. 2, an example where the emission intensity gradually decreases is shown, but depending on the conditions, the emission intensity may increase.

[0031] Next, when the etching of the target film is completed, as shown in period PRD4, the emission intensity of the plasma becomes a certain intensity.

[0032] As shown in FIG. 2, even if the fluctuation of the emission intensity is measured, there may be cases where the end point of etching cannot be sufficiently detected.

[0033] Therefore, the inventors have found that by simultaneously measuring the emission intensity and the electron density or a parameter having a strong correlation with the electron density, the influence of the electron density can be suppressed.

[0034] FIG. 3 is a diagram for explaining the processing in a plasma processing system S which is an example of the plasma processing system according to the present embodiment. The horizontal axis in FIG. 3 conceptually indicates the electron density, and the vertical axis indicates the emission intensity.

[0035] When the emission intensity changes due to the influence of the electron density, as shown by arrow B1 in FIG. 3, both the electron density and the emission intensity increase. When the emission intensity changes due to the influence of the gas, as shown by arrow B2 in FIG. 3, only the emission intensity changes and the electron density does not change.

[0036] Therefore, the inventors have found that when the electron density does not change much and the emission intensity changes greatly, it may be determined that it is the end point in the plasma processing. For example, when a scatter plot is shown as a two-dimensional graph with the electron density on the horizontal axis and the emission intensity on the vertical axis, when the emission intensity fluctuates due to the gas, the data fluctuates in the vertical direction of the graph. Therefore, the inventors have found that when the data fluctuates in the vertical direction in a scatter plot with the electron density on the horizontal axis and the emission intensity on the vertical axis, it may be determined that it is the end point in the plasma processing. Viewed from another perspective, the inventors have found that when the absolute value of the first change rate in the electron density is less than or equal to the first threshold value and the absolute value of the second change rate in the emission intensity is greater than or equal to the second threshold value, it may be determined that it is the end point in the plasma processing. That is, the inventors have found that when the change in the electron density is small and the change in the emission intensity is large, it may be determined that it is the end point in the plasma processing.

[0037] Specifically, the control unit 2 in the plasma processing system S determines that it is the end point in the plasma processing when the absolute value of the first change rate in the electron density is less than or equal to the first threshold value and the absolute value of the second change rate in the emission intensity is greater than or equal to the second threshold value.

[0038] A specific operation example in the plasma processing system S will be described. FIG. 4 is a diagram showing an example of the measurement result of the emission intensity in the plasma processing system S which is an example of the plasma processing system according to the present embodiment. FIG. 4 shows the emission intensity of the carbon nitride gas which is a by-product when etching silicon nitride in a state where the aperture ratio is low (aperture ratio 0.6%).

[0039] In FIG. 4, the horizontal axis represents the time (unit: second) since the start of plasma generation, and the vertical axis represents the emission intensity (unit: arbitrary unit). The line L1 shows the measurement result. Note that the output increases from time 0 seconds to time 5 seconds.

[0040] FIG. 5 is a diagram showing an example of the relationship between the electron density correlation parameter and the emission intensity in the plasma processing system S which is an example of the plasma processing system according to the present embodiment. FIG. 5 shows the measurement result in FIG. 4.

[0041] In FIG. 5, the horizontal axis represents the parameter correlated with the electron density (electron density correlation parameter) (unit: arbitrary unit), and the vertical axis represents the emission intensity (unit: arbitrary unit). The line L2 shows the measurement result.

[0042] The point T0 corresponds to 0 seconds in FIG. 4. Note that the data near time 0 seconds is omitted because the emission intensity is small. Similarly, the points T10, T20, T30, T40, T50, T60, and T75 correspond to time 10 seconds, time 20 seconds, time 30 seconds, time 40 seconds, time 50 seconds, time 60 seconds, and time 75 seconds in FIG. 4 respectively.

[0043] As shown in FIG. 5, between time 10 seconds and time 20 seconds, the fluctuation of the electron density correlation parameter is small, and as shown by arrow C1, a portion with a large fluctuation in the emission intensity is found. The control unit 2 detects the fluctuation as shown by arrow C1 and determines that it is the end point in the plasma processing. For example, the control unit 2 calculates a first change rate in the electron density measured by the electron density measurement unit 60. Then, the control unit 2 calculates a second change rate in the emission intensity measured by the emission intensity measurement unit 50. And when the absolute value of the first change rate is equal to or less than a first threshold value, that is, the fluctuation of the electron density is small, and the absolute value of the second change rate is equal to or greater than a second threshold value, that is, the fluctuation of the emission intensity is large, the control unit 2 determines that it is the end point in the plasma processing. Also, the control unit 2 may perform end point determination using the slope of line L2 in FIG. 5.

[0044] In the conventional end point detection, when the etching is completed, the end point is detected by using the fact that an inflection point occurs in the emission intensity. However, in the results in FIG. 4, due to the low aperture ratio, the emission intensity due to the by-products is buried in the noise, and the inflection point of the emission intensity due to the by-products cannot be detected.

[0045] According to the plasma processing system S which is an example of the plasma processing system according to the present embodiment, as shown in FIG. 5, the point that becomes the end point can be detected.

[0046] Another example will be described. An example in the case where the aperture ratio is increased (aperture ratio 5.1%) will be described. FIG. 6 is a diagram showing an example of the measurement result of the emission intensity in the plasma processing system S which is an example of the plasma processing system according to the present embodiment.

[0047] In FIG. 6, the horizontal axis is the time (unit: second) since the start of plasma generation, and the vertical axis is the emission intensity (unit: arbitrary unit). Line L3 shows the measurement result.

[0048] FIG. 7 is a diagram showing an example of the relationship between the electron density correlation parameter and the emission intensity in a plasma processing system S, which is an example of the plasma processing system according to the present embodiment. FIG. 7 shows the measurement results in FIG. 6.

[0049] In FIG. 7, the horizontal axis represents a parameter (electron density correlation parameter) correlated with the electron density (unit: arbitrary unit), and the vertical axis represents the emission intensity (unit: arbitrary unit). The line L4 shows the measurement results.

[0050] The point T0 corresponds to 0 seconds in FIG. 6. Note that the data near time 0 seconds is omitted because the emission intensity is small. Similarly, the points T10, T20, T30, T40, T50, T60, and T75 correspond to time 10 seconds, time 20 seconds, time 30 seconds, time 40 seconds, time 50 seconds, time 60 seconds, and time 75 seconds in FIG. 6, respectively.

[0051] As shown in FIG. 7, between 40 seconds and 60 seconds, a portion where the variation of the electron density correlation parameter is small and the variation of the emission intensity is large is found. The control unit 2 detects a point where the variation of the electron density correlation parameter is small and the emission intensity is varying near 40 seconds, and determines that it is the end point in the plasma processing. Specifically, the control unit 2 determines that it is the end point in the plasma processing when the absolute value of the first change rate in the electron density is less than or equal to the first threshold and the absolute value of the second change rate in the emission intensity is greater than or equal to the second threshold. That is, when the variation of the electron density is small and the absolute value of the second change rate is greater than or equal to the second threshold, that is, when the variation of the emission intensity is large, it is determined that it is the end point in the plasma processing. Further, the control unit 2 may perform end point determination using the slope of the line L2 in FIG. 5.

[0052] As described above, according to the plasma processing system according to the present embodiment, the influence of the electron density on the emission intensity can be suppressed.

[0053] According to the plasma processing system according to this embodiment, by discriminating between the influence of the change in electron density and the influence of the change in gas on the change in emission intensity, it is possible to remove the influence of the change due to the electron density that causes false detection. Further, according to the plasma processing system according to this embodiment, by discriminating between the influence of the change in electron density and the influence of the change in gas on the change in emission intensity, it is possible to amplify more the change due to the gas density to be detected. Furthermore, according to the plasma processing system according to this embodiment, by discriminating between the influence of the change in electron density and the influence of the change in gas on the change in emission intensity, it is possible to detect a rapid electron density due to the capacitance fluctuation of the variable capacitor or plasma leakage. And, according to the plasma processing system according to this embodiment, by detecting a rapid electron density, it is possible to suppress false detection with respect to the change in emission intensity.

[0054] Also, the inventors have found that by correcting the emission intensity according to the electron density, it is possible to suppress the influence of the electron density on the emission intensity. That is, the inventors have found that it is possible to calculate the corrected emission intensity by correcting based on the electron density.

[0055] Specifically, the control unit 2 in the plasma processing system S calculates the corrected emission intensity by correcting based on the electron density.

[0056] FIG. 8 is a diagram showing the relationship between the electron density and the emission intensity in a plasma processing system S which is an example of the plasma processing system according to this embodiment.

[0057] The horizontal axis of FIG. 8 is the electron density, and the vertical axis is the emission intensity. As described above, the emission intensity is affected by the electron density. If the change in the emission intensity due only to the influence of the electron density is known in advance, the amount of change in the emission intensity due to the gas can be calculated. For example, as shown in FIG. 8, the relationship between the electron density and the emission intensity may be obtained in advance, and the correction line CL may be obtained by a linear regression equation as shown in FIG. 8. Then, the emission intensity may be corrected using the correction line CL, that is, using the correction coefficient between the emission intensity and the electron density. The regression equation is not limited to linear, and may be quadratic or higher.

[0058] FIG. 9 is a diagram showing the measurement results of the emission intensity in the plasma processing system S which is an example of the plasma processing system according to the present embodiment. The horizontal axis in FIG. 9 is time (unit: second), and the vertical axis is the emission intensity or the high-frequency power (unit: arbitrary unit). The line L11 indicates the high-frequency power. The line L12 indicates the emission intensity of the carbon difluoride radical (CF2, emission wavelength: 252.0 nm, emission intensity A). The line L13 indicates the emission intensity of the oxygen molecule (O2, emission wavelength: 777.5 nm, emission intensity B).

[0059] As shown as PE2 in FIG. 9, when the high-frequency power is turned off, a bump can be formed in the emission spectrum of the carbon difluoride radical (CF2) shown by the line L12. Also, as shown as PE3 in FIG. 9, when the high-frequency power is turned on, a corner can be formed in the emission spectrum of the oxygen molecule (O2) shown by the line L13.

[0060] FIG. 10 is a diagram showing the result of correcting the measurement result of the emission intensity of FIG. 9 in the plasma processing system S which is an example of the plasma processing system according to the present embodiment. The horizontal axis in FIG. 10 is time (unit: second), and the vertical axis is the emission intensity or the high-frequency power (unit: arbitrary unit). The line L21 indicates the high-frequency power. The line L22 indicates the emission intensity of the carbon difluoride radical (CF2, emission wavelength: 252.0 nm, emission intensity A). The line L23 indicates the emission intensity of the oxygen molecule (O2, emission wavelength: 777.5 nm, emission intensity B).

[0061] By correcting using the result of measuring the electron density shown in FIG. 8, as shown in FIG. 10, the bulge shown as PE2 and the corner shown as PE3 in FIG. 9 can be removed by correction.

[0062] As described above, according to the plasma processing system according to this embodiment, the influence of the electron density on the emission intensity can be suppressed.

[0063] Also, for example, when the gas is switched, the plasma processing chamber 10 becomes unstable. When the plasma processing chamber 10 is unstable, the electron density also changes together. When the electron density changes, as described above, since the emission intensity changes, it is difficult to identify only the gas switching. According to the plasma processing apparatus according to this embodiment, by correcting the emission intensity according to the electron density, only the change due to the gas can be extracted.

[0064] Furthermore, according to the plasma processing system according to this embodiment, the ion flow can be estimated from the electron density inside the plasma processing chamber 10. By estimating the ion flow from the electron density inside the plasma processing chamber 10, the machine differences of the plasma processing chamber 10 can be confirmed.

[0065] The plasma processing system according to the present embodiment disclosed this time should be considered to be illustrative in all respects and not restrictive. The above embodiments can be modified and improved in various forms without departing from the scope and gist of the appended claims. The matters described in the above plurality of embodiments can take other configurations within a non - conflicting range, and can also be combined within a non - conflicting range.

Description of Reference Numerals

[0066] S Plasma processing system 1 Plasma processing apparatus 2 Control unit 10 Plasma processing chamber 50 Emission intensity measurement unit 60 Electron density measurement unit

Claims

1. A plasma processing chamber for housing a substrate therein, an emission intensity measurement unit for measuring the emission intensity of a wavelength caused by by-products or process gases in plasma processing inside the plasma processing chamber, an electron density measurement unit for measuring the electron density inside the plasma processing chamber, and a control unit for determining that it is the end point in the plasma processing when the change in the electron density measured by the electron density measurement unit is small and the change in the emission intensity measured by the emission intensity measurement unit is large. The plasma processing system is provided with: A plasma processing system.

2. A plasma processing chamber for housing a substrate therein, an emission intensity measurement unit for measuring the emission intensity inside the plasma processing chamber, an electron density measurement unit for measuring the electron density inside the plasma processing chamber, and a control unit for calculating a corrected emission intensity by correcting the emission intensity measured by the emission intensity measurement unit using the electron density measured by the electron density measurement unit and a correction coefficient of the emission intensity and the electron density calculated in advance. The plasma processing system is provided with: A plasma processing system.

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