JP2006086325A - End point detecting method of cleaning - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect surely the end point of cleaning without being affected by factors such as the measuring position of emission intensity, cleaning condition, the fluctuation of plasma or the like. <P>SOLUTION: A wafer W, whose film forming process is finished, is carried out of a chamber 2 and, thereafter, the inside of the chamber 2 is evacuated and cleaning gas is introduced through a gas introducing port 7. High-frequency power is impressed on a shower head 5 from a high-frequency power supply 30 to generate high-frequency electric field between an upper electrode or the shower head 5 and a lower electrode or a susceptor 3 to change the cleaning gas into plasma. The emission intensity of radical in plasma in the chamber 2 is measured by a spectrum 22 during cleaning to obtain automatically a ratio D/I or a ratio of a spectrum (D) which is reduced in accordance with the advance of cleaning to another spectrum (I) which is increased in accordance with the advance of cleaning and make a chart with respect to the ratio whereby the end point of cleaning is detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for detecting an end point of cleaning, and more particularly to a method for detecting an end point when cleaning a processing chamber used for, for example, plasma CVD (Chemical Vapor Deposition).

In a plasma CVD process for forming a film on the surface of a semiconductor wafer, a film component adheres not only to the surface of the semiconductor wafer but also to the inner wall surface of the processing chamber to form a deposit. For this reason, it is necessary to periodically clean the processing chamber used for the plasma CVD process. As a cleaning method, plasma cleaning using plasma of a cleaning gas is employed. In this plasma cleaning, the time change of the emission intensity of radicals such as CO radicals, F radicals, O radicals and H radicals contained in the plasma in the processing chamber is measured, and this is used as an index to determine the end point of cleaning. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 63-14421 (claims)

  In the method of Patent Document 1, sufficient light emission intensity cannot be obtained depending on the measurement position for measuring the light emission intensity and the cleaning conditions, and it is difficult to accurately determine the end point of cleaning for the reasons described below. was there.

  In general, plasma CVD using organic compounds such as TMS (trimethylsilane) tends to increase the deposition rate as the temperature is lower, compared to the periphery of the substrate or stage heater (mounting table) and other high-temperature substrates. The amount of deposition on the inner wall of the chamber and the shower head (upper electrode), which is at a low temperature, is overwhelmingly large. FIG. 6 shows a condition that a parallel plate type plasma CVD apparatus is used, TMS / He is set at a flow rate of 150/800 mL / min, high-frequency power 800 W to the upper electrode, pressure of about 1040 Pa (7.8 Torr), and distance between the upper and lower electrodes of 18 mm. FIG. 5 is a graph showing the deposition rate when the temperature is varied in the range of 100 to 300 ° C. FIG. FIG. 6 shows that there is a clear correlation between the temperature in the chamber and the deposition amount by plasma CVD, and the deposit increases as the temperature decreases.

  In addition, when a low-k film or the like is formed using an organic compound raw material, the bond specific to the raw material is incorporated into the film by suppressing the input of high-frequency power into the chamber and suppressing the decomposition of the raw material. I have to. In film formation on the substrate, the film quality is determined by the balance between decomposition / desorption of the raw material components by thermal decomposition, but since the decomposition / desorption of the raw material components is small in the low temperature part in the chamber, a large amount of deposition is performed. Things will be formed. For example, when the substrate temperature is about 300 ° C., the temperature of the chamber wall is 80 to 90 ° C., and the temperature of the upper electrode rises due to the heat of the substrate and plasma, but is only about 150 ° C. It is clearly cooler than that. For this reason, a large amount of deposits are formed on the upper electrode that functions as a shower head for supplying the raw material into the chamber, and it is possible to reliably perform the cleaning process on this portion in order to prevent particle generation and film reproducibility. It becomes important in making a decision.

As countermeasures against the above problems, for example, in order to uniformly remove deposits at different sites such as members around the substrate mounting position (for example, lower electrode), chamber inner wall, upper electrode, etc., cleaning is divided into multiple steps. However, it is necessary to select a cleaning condition suitable for a target site in each step. In this case, it is necessary to change the conditions such as electric power, gas flow rate, pressure, and electrode distance (gap) for each step, and to switch between continuous output / pulse output of the power source during cleaning.
However, since the plasma light emission in the chamber greatly fluctuates as the cleaning conditions change, it is very difficult to monitor the change in light emission intensity over time for a single element and grasp the end point. In other words, if the emission intensity entering the luminescence measuring instrument (spectrometer) changes as a whole due to the overall fluctuation of the plasma, the intensity of the wavelength of interest also changes, but this is mistaken as an intensity change due to the progress of cleaning. May not be accurate.

On the other hand, in order to maintain the productivity in plasma CVD, plasma cleaning using a fluorine-based gas such as NF ₃ requires a high power supply in order to remove a large amount of deposits in a short time. Corrosion of the electrode itself and dust generation due to parts damage are also serious problems. In order to suppress such corrosion and part damage, a cleaning method is generally performed in which only radicals plasma-excited outside the chamber by a remote plasma method are supplied into the chamber. In the case of this remote plasma cleaning, it is extremely difficult to detect radical luminescence, and it is necessary to take some measures for end point detection.

  Therefore, the object of the present invention is not affected by factors such as the emission intensity measurement position, cleaning conditions, and plasma fluctuations, and it is possible to reliably detect the end point of cleaning even in the case of remote plasma cleaning. Another object of the present invention is to provide a method for detecting the end point of cleaning.

In order to solve the above problems, according to the first aspect of the present invention, in cleaning a CVD processing container, an end point detection method for detecting the end point of cleaning by measuring radical emission intensity in the processing container,
A cleaning end point detection method characterized in that a ratio D / I between a radical emission intensity D that decreases as cleaning progresses and a light emission intensity I of a radical that increases increases, and the end point is detected from the change over time. Provided.

  In the endpoint detection method according to the first aspect, the CVD may be plasma CVD using an organic compound as a raw material. Here, the organic compound may contain Si and hydrogen or nitrogen, and the plasma CVD may be a film containing Si as a constituent element. The organic compound may be trimethylsilane.

Further, the plasma CVD may be the formation of a film further containing hydrogen or nitrogen as a constituent element. In addition, a gas containing a halogen compound gas and oxygen can be used as the cleaning gas. Here, the halogen compound gas may be NF ₃ . Further, the radical that decreases as the cleaning progresses may be an atomic or molecular radical containing a constituent element of the film, and the increasing radical may be a fluorine radical or an oxygen radical. Further, the atomic or molecular radical containing the constituent elements of the film may be a hydrogen radical.

  The cleaning may be performed by generating radicals by plasma excitation. In this case, the cleaning can be performed by changing the plasma excitation condition for each part in the processing container. Cleaning can also be performed by remote plasma that introduces radicals excited by plasma into the processing vessel.

  Further, the end point may be detected by inserting a plasma excitation step for detecting the end point during the cleaning. The plasma excitation step for end point detection may be performed by exciting plasma using a parallel plate type plasma apparatus.

According to the present invention, by determining the ratio D / I of the radical emission intensity D that decreases with the progress of cleaning and the emission intensity I of the radical that increases, the progress of cleaning is emphasized. The end point can be clearly grasped from.
Further, by using the light emission intensity ratio D / I, the end point of cleaning can be accurately grasped without being influenced by the change of the overall light emission intensity due to the fluctuation of plasma.
According to the present invention, even in remote plasma cleaning, the end point of cleaning can be reliably detected by inserting the plasma excitation step for detecting the end point during cleaning and detecting the end point.

The cleaning end point detection method of the present invention is an end point detection method for detecting the end point of cleaning by measuring radical emission intensity in a processing container when cleaning a CVD processing container,
The ratio D / I between the radical emission intensity D that decreases as the cleaning progresses and the radical emission intensity I that increases increases, and the end point is detected from the change over time.

  The CVD process to which the end point detection method of the present invention is applied is a film forming process using a thermal CVD method, a plasma CVD method, or the like, and can be suitably applied to a plasma CVD method in which a film is formed using plasma. When cleaning a processing container used for the thermal CVD method, it is necessary to provide a plasma generation device for end point detection.

  A film to be formed by the CVD process is not particularly limited, but a film formed by plasma CVD using an organic compound as a raw material is preferable. Here, the organic compound is preferably an organic compound containing Si and hydrogen or nitrogen, and examples thereof include trimethylsilane, dimethylethoxysilane, triethylsilazane, and tetramethyldisilazane.

Further, as a film to be formed, a Si-based film containing Si as a constituent element of the film is preferable, and a film containing hydrogen or nitrogen is more preferable. Since radicals generated from these elements have high emission intensity and are difficult to overlap with radicals of cleaning gas constituent elements (halogen, oxygen, etc.), they are advantageous in that they can be easily distinguished.
Examples of the Si-based film containing hydrogen or nitrogen as a constituent element include a SiC-based film and a SiN-based film. Here, examples of the SiC-based film include a SiCH film and a SiOCH film. Examples of the SiN film include a SiCN film, a SiON film, and a SiN film.

Moreover, as a film other than the film containing hydrogen or nitrogen, for example, a SiO ₂ film can be given.

  As a cleaning method of the processing container, plasma cleaning in which cleaning is performed with plasma of a cleaning gas is preferable, but plasma rescreening in which cleaning is performed by heat, chemical action of a cleaning gas, or the like without using plasma may be used.

As the cleaning gas, a gas containing a halogen element such as fluorine or oxygen as a constituent element is preferably used, and examples thereof include a mixed gas of a halogen compound and / or oxygen and an inert gas as a carrier. As NF ₃ / O ₂ / He, NF ₃ / O ₂ / Ar, NF ₃ / He, NF ₃ / Ar, COF ₂ / He, COF ₂ / Ar, CF ₄ / He, CF ₄ / Ar, CF Examples thereof include mixed gases such as ₄ / O ₂ / He and CF ₄ / O ₂ / Ar.

In the method of the present invention, D / I, which is an index for detecting the end point of cleaning, is obtained as a ratio between the emission intensity D of radicals that decrease as cleaning progresses and the emission intensity I of radicals that increase. Here, the “radical that decreases as the cleaning progresses” is an atomic or molecular radical that contains the constituent elements of the film, and the “radical that increases as the cleaning progresses” is the atomic or molecular radical that contains the constituent elements of the cleaning gas. It is a radical. For example, in a CVD process for forming a SiCH film, when cleaning is performed using plasma of a mixed gas of NF ₃ / O ₂ / He as a cleaning gas for a processing container, “radicals that decrease as cleaning progresses”. Corresponds to a hydrogen radical (H ^* ) derived from a membrane component. In the process in which deposits in the processing container are removed by plasma cleaning, hydrogen contained therein becomes radicals. The reason why the emission intensity of hydrogen radicals decreases with the progress of cleaning is that the generation of radicals is large in the initial stage of cleaning, but the rate of radical generation decreases as the removal of deposits proceeds. Conceivable.

In the above case, “radicals that increase as cleaning progresses” corresponds to fluorine radicals (F ^* ) and oxygen radicals (O ^* ) derived from the cleaning gas. The emission intensity of these radicals is low because they are consumed in the reaction with deposits at the initial stage of cleaning, but the emission intensity increases because the proportion of radicals that are not consumed increases as the removal of deposits proceeds. Conceivable.

  The emission intensity D of “radicals that decrease with the progress of cleaning” and the emission intensity I of “radicals that increase with the progress of cleaning” generate plasma in the processing vessel, and emit light of the radicals in the plasma, for example, a spectroscope It can detect by measuring using. When the cleaning method is plasma cleaning, light emission of radicals in the processing container being cleaned may be measured as it is. When the cleaning method is plasma rescreening, the emission intensity can be measured by generating plasma for the purpose of end point detection in the processing container.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a schematic configuration of a plasma CVD apparatus 1 suitable for implementing the present invention. The plasma CVD apparatus 1 is configured as a capacitively coupled parallel plate plasma CVD apparatus in which electrode plates face each other in the vertical direction.

  The plasma CVD apparatus 1 has a chamber 2 as a processing container formed in a cylindrical shape made of aluminum whose surface is ceramic sprayed, for example, and the chamber 2 is grounded for safety. In the chamber 2, a wafer W made of, for example, silicon and on which a predetermined film is formed is placed, and a susceptor 3 functioning as a lower electrode is provided. A conductor 34 is embedded in the susceptor 3, and a high-frequency power is supplied through the conductor 34. The susceptor 3 is supported by a support base 4 and can be moved up and down by a lifting mechanism (not shown).

  The susceptor 3 is formed into a convex disk shape at the center of the upper portion, and an electrostatic chuck (not shown) is provided on which an electrode is interposed between insulating materials. By applying a DC voltage, the wafer W can be electrostatically attracted by, for example, Coulomb force.

  Above the susceptor 3, a shower head 5 that functions as an upper electrode is provided in parallel with the susceptor 3. The shower head 5 is supported on the upper portion of the chamber 2 via an insulating material, and has a large number of discharge holes 6, 6,... On the surface 5 a facing the susceptor 3. The surface of the wafer W and the shower head 5 are separated from each other at a predetermined interval, and this distance can be adjusted by the elevating mechanism.

  The shower head 5 is provided with a gas introduction port 7 and communicates with the discharge hole 6 through a gas supply chamber 5 b inside the shower head 5. Further, the gas inlet 7 is connected to a gas supply system 10 for supplying a film forming gas and a cleaning gas via a gas supply pipe 8 and a valve 9.

The gas supply system 10 includes a film forming gas supply source 11 and a cleaning gas supply source 12, and a valve 13 and a mass flow controller 14 are provided in the piping from these gas sources, respectively. In the present embodiment, (CH ₃ ) ₃ SiH / He is used as a film forming gas by CVD, and NF ₃ / O ₂ / He is used as a cleaning gas. The film forming gas and the cleaning gas reach the space in the shower head 5 through the gas inlet 7 and are discharged from the discharge hole 6.

  An exhaust pipe (not shown) is connected to the side wall of the chamber 2 (near the susceptor 3), and the inside of the chamber 2 is evacuated to a predetermined reduced-pressure atmosphere, for example, a predetermined pressure of 1 Pa or less by a vacuum pump such as a turbo molecular pump. It is configured so that it can be pulled. In addition, a loading / unloading port for the wafer W and a gate valve for opening and closing the loading / unloading port are provided on the side wall of the chamber 2 (both are not shown) so that the wafer W is transferred through these. It has become.

  Further, a translucent window 20 is provided at the lower part of the side wall of the chamber 2. A light receiving unit 21 is provided adjacent to the window 20, and the light receiving unit 21 is electrically connected to a spectrometer 22 for measuring the emission intensity of plasma. Since the position where the window 20 is provided is far from the upper and lower electrodes (shower head 5 and susceptor 3), it is not easily affected by the plasma generated between the electrodes and is not an exhaust path. There is an advantage that the measurement can be performed stably with less deposits.

  A high frequency power source 30 is connected to the shower head 5 functioning as an upper electrode, and a matching unit 31 is interposed in the power supply line. The high frequency power supply 30 supplies high frequency power having a frequency of, for example, 13.56 MHz to the shower head 5 and forms a high frequency electric field for plasma formation between the shower head 5 as the upper electrode and the susceptor 3 as the lower electrode. . The shower head 5 is connected to a low-pass filter (LPF) (not shown).

  A high frequency power supply 32 is connected to the susceptor 3 functioning as a lower electrode, and a matching unit 33 is interposed in the power supply line. The high-frequency power source 32 can supply high-frequency power having a frequency of, for example, 2.0 MHz to the susceptor 3 that is the lower electrode. The susceptor 3 is connected to a high pass filter (HPF) (not shown).

  In the plasma CVD apparatus 1 having the above configuration, when a film is formed on the surface of the wafer W, the wafer W is first placed on the susceptor 3 and adsorbed and left by an electrostatic chuck (not shown). Next, the inside of the chamber is exhausted to a predetermined degree of vacuum by an exhaust device (not shown). The support table 4 is raised by an elevating mechanism (not shown) to place the wafer W at the processing position. In this state, the susceptor 3 is controlled to a predetermined temperature, and the inside of the chamber 2 is evacuated by an exhaust device (not shown) to obtain a predetermined high vacuum state.

  Thereafter, the film forming gas is supplied from the film forming gas supply source 11 to the chamber 2 at a predetermined flow rate. The film forming gas supplied to the shower head 5 is uniformly discharged toward the wafer W from the discharge holes 6. Then, a high frequency power of, for example, about 13.56 MHz is applied from the high frequency power supply 30 to the shower head 5, thereby generating a high frequency electric field between the shower head 5 as the upper electrode and the susceptor 3 as the lower electrode, The film forming gas is turned into plasma. This plasma is drawn in the vicinity of the susceptor 3 to which power having a frequency lower than that of the high frequency power applied to the shower head 5 is applied. The drawn plasma causes a chemical reaction on the surface of the wafer W, and a film such as SiCH is formed on the surface of the wafer W.

  Next, cleaning in the chamber 2 in the plasma CVD apparatus 1 will be described. When cleaning the chamber 2, after the film-formed wafer W is unloaded from the chamber 2, the inside of the chamber 2 is decompressed and a cleaning gas is introduced from the gas inlet 7. Then, a high frequency power of, for example, about 13.56 MHz is applied from the high frequency power supply 30 to the shower head 5, thereby generating a high frequency electric field between the shower head 5 as the upper electrode and the susceptor 3 as the lower electrode. The cleaning gas is turned into plasma. The plasma of the cleaning gas reacts with deposits attached to the inner wall surface of the chamber 2 and removes them.

  The cleaning is preferably performed by dividing into a plurality of steps and selecting cleaning conditions suitable for the target site in each step. For example, in order to perform uniform cleaning on the parts with different amounts of deposits such as the susceptor 3 as the lower electrode, the inner wall of the chamber 2 and the shower head 5 as the upper electrode, the power, gas flow rate, pressure, It is preferable to change conditions such as the distance (gap) between the electrodes, and to switch the power output from continuous to pulse or from pulse to continuous during cleaning.

  During cleaning, the spectroscope 22 measures the emission intensity of radicals in the plasma in the chamber 2. The spectroscope 22 divides plasma emission detected by the light receiving unit 21 into spectra. The ratio D / I between the spectrum (D) that decreases with the progress of cleaning and the spectrum (I) that increases with the progress of cleaning is automatically calculated from the emission spectra of radicals measured by the spectrometer 22. Thus, the end point of cleaning can be detected by charting. By using the D / I ratio as an index, the change in the chart is reduced, and the end point of cleaning can be determined by the time when the chart is stabilized. The end point may be determined by, for example, obtaining the slope of the tangent line of the chart indicating the D / I ratio by differentiation.

  When a plurality of cleaning steps are performed under different conditions according to the cleaning target part, the progress of the cleaning of the cleaning target part can be accurately grasped by obtaining the D / I ratio for each step. This is because by calculating the D / I ratio, it is possible to reduce the influence of fluctuations in the cleaning conditions that differ for each cleaning step.

When the plasma CVD apparatus 1 is cleaned, a remote plasma method is performed in which plasma is separately generated outside the apparatus and excited radicals are introduced into the chamber 2 to suppress corrosion / part damage of the upper electrode and the like. Cleaning is also possible. In this case, since it is difficult to detect the emission of radicals, for the purpose of detecting the end point of cleaning, a plasma excitation step for detecting the end point can be inserted during cleaning to detect the end point. Here, in the plasma excitation step for end point detection, the end point detection plasma is started up once or several times during cleaning, preferably every fixed time, in the parallel plate type plasma CVD apparatus 1 shown in FIG. The plasma conditions at this time are not limited as long as radical emission can be detected by the light receiving unit 21 and measured by the spectroscope 22. For example, 250 W is supplied to the shower head 5, and 0 W is supplied to the susceptor 3 as the lower electrode, and NF ₃ / He flow rate 220/1000 mL / min, pressure 65 Pa, upper and lower electrode gap 26 mm can be set.

  In the case of plasma rescreening, where cleaning is performed by heat or the chemical action of a cleaning gas, a plasma excitation step for detecting the end point is inserted during cleaning under the same conditions as in the case of the remote plasma method, and the end point is detected. Can be performed.

Test example 1
Plasma cleaning was performed on the chamber 2 after the SiCH film was formed on the wafer W using the plasma CVD apparatus 1 of FIG. A high frequency power of 600 W is supplied to the shower head 5 as the upper electrode and 0 W to the susceptor 3 as the lower electrode, NF ₃ / O ₂ / He is used as the cleaning gas at a flow rate of 220/110/1000 mL / min, a pressure of 65 Pa, Plasma was generated under the condition of a gap between the upper and lower electrodes of 26 mm, and chamber cleaning was performed.

During cleaning, the emission intensity of fluorine radicals (F ^* ), oxygen radicals (O ^* ) and hydrogen radicals (H ^* ) contained in the plasma in the chamber was continuously measured using the spectroscope 22. Here, the spectrum of H ^* (wavelength 656 nm) is a spectrum (D) that decreases with the progress of cleaning, and the spectrum of F ^* (wavelength 704 nm) and the spectrum of O ^* (wavelength 777 nm) are the progress of cleaning. The spectrum (I) increases with the increase. Based on these measurement results, D / I ratios (H ^* / F ^* and H ^* / O ^* ) were determined and charted. The result is shown in FIG.
For comparison, FIG. 3 shows the results of charting the spectra of H ^* , F ^* and O ^* as they are.

  From the comparison between FIG. 2 and FIG. 3, the ratio D / I of the spectrum (D) that decreases with the progress of cleaning and the spectrum (I) that increases with the progress of cleaning is obtained. It was shown that endpoints can be determined more accurately because changes are emphasized and changes in two wavelengths are reflected.

Test example 2
As cleaning conditions, the supply of high-frequency power is set to 400 W for the shower head 5 as the upper electrode and 60 W to the susceptor 3 as the lower electrode, and NF ₃ / O ₂ / He is used as the cleaning gas at a flow rate of 563/187/1000 mL / min. Cleaning was performed in the same manner as above except that the pressure was changed to 65 Pa and the gap between the upper and lower electrodes was 22 mm, and the emission intensity of the plasma in the chamber was measured, and the D / I ratio (H ^* / F ^* , and H ^* / O ^* ) was obtained and charted. The result is shown in FIG.

For comparison, FIG. 5 shows the results of charting the spectra of H ^* , F ^* and O ^* as they are.

From the comparison between FIG. 4 and FIG. 5, it is difficult to determine the end point as shown in FIG. 5 just by charting the emission spectra of H ^* , F ^* and O ^* as they are, By determining the ratio D / I between the spectrum (D) that decreases with the progress and the spectrum (I) that increases with the progress of cleaning, the change in the emission intensity is emphasized and the change in the two wavelengths is reflected. Therefore, it was shown that the endpoint can be determined more accurately.

As mentioned above, although embodiment of this invention was described, this invention is not restrict | limited to the said embodiment, A various deformation | transformation is possible.
For example, in the above-described embodiment, the cleaning of the plasma CVD apparatus has been described as an example. However, the plasma may not be used for the CVD film formation and the cleaning as long as the apparatus can use the plasma for detecting the end point of the cleaning. . In other words, the cleaning target may be a processing container of a thermal CVD apparatus that does not use plasma.

  Further, the plasma CVD apparatus is not limited to a parallel plate type plasma CVD apparatus, and the present invention can be similarly applied to a plasma CVD apparatus adopting an inductive coupling method (ICP). Furthermore, the present invention can be similarly applied to a remote plasma type plasma CVD apparatus as long as it has a mechanism capable of generating plasma in the processing container for detecting the end point of cleaning.

  The present invention can be used for cleaning the inside of a processing vessel used in a CVD apparatus such as a plasma CVD apparatus or a thermal CVD apparatus.

Sectional drawing which shows the outline of the plasma CVD apparatus suitable for implementation of the method of this invention. 2 is a diagram showing a chart of radical emission intensity ratio D / I according to the method of the present invention in Test Example 1. FIG. The figure which shows the chart of the emitted light intensity of the radical by the comparison method in Test Example 1. The figure which shows the chart of the luminescence intensity ratio D / I of the radical by the method of the present invention in Test example 2. The figure which shows the chart of the emitted light intensity of the radical by the comparison method in Test Example 2. The graph figure which shows the relationship between the temperature and deposition rate in plasma CVD.

Explanation of symbols

1: Plasma CVD apparatus 2: Chamber 3: Susceptor 4: Support base 5: Shower head 6: Discharge hole 7: Gas inlet 8: Gas supply pipe 9: Valve 10: Gas supply system 11: Gas supply source 12 for film formation : Cleaning gas supply source 13: Valve 14: Mass flow controller 20: Window 21: Light receiving unit 22: Spectroscope 30: High frequency power supply 31: Matching device 32: High frequency power supply 33: Matching device 34: Conductor

Claims (14)

In cleaning the CVD processing container, it is an end point detection method for detecting the end point of cleaning by measuring radical emission intensity in the processing container,
A method for detecting an end point of cleaning, characterized in that a ratio D / I between a radical emission intensity D that decreases as cleaning progresses and an emission intensity I of a radical that increases increases, and an end point is detected from the change over time.   The end point detection method according to claim 1, wherein the CVD is plasma CVD using an organic compound as a raw material.   The end point detection method according to claim 2, wherein the organic compound contains Si and hydrogen or nitrogen, and the plasma CVD is film formation of a film containing Si as a constituent element.   The end point detection method according to claim 3, wherein the organic compound is trimethylsilane.   The end point detection method according to claim 3, wherein the plasma CVD is film formation of a film further containing hydrogen or nitrogen as a constituent element.   6. The end point detection method according to claim 1, wherein a gas containing a halogen compound gas and oxygen is used as the cleaning gas. The end point detection method according to claim 6, wherein the halogen compound gas is NF ₃ .   The end point detection method according to claim 7, wherein the radical that decreases as the cleaning progresses is an atomic or molecular radical containing a constituent element of the film, and the increasing radical is a fluorine radical or an oxygen radical. .   The end point detection method according to claim 8, wherein the atomic or molecular radical containing the constituent element of the film is a hydrogen radical.   The end point detection method according to any one of claims 1 to 9, wherein the cleaning is performed by generating radicals by plasma excitation.   The end point detection method according to claim 10, wherein the cleaning is performed by changing plasma excitation conditions for each part in the processing container.   The end point detection method according to claim 10, wherein the cleaning is performed by remote plasma in which radicals excited by plasma are introduced into the processing container.   The end point detection method according to any one of claims 1 to 12, wherein a plasma excitation step for end point detection is inserted during the cleaning to detect the end point.   The endpoint detection method according to claim 13, wherein the plasma excitation step for endpoint detection is performed by exciting plasma using a parallel plate plasma apparatus.

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