JPH07273092A - Plasma treatment apparatus and its cleaning method - Google Patents

Abstract

PURPOSE:To clean a reaction chamber easily without giving damages to a sample table by a method wherein, in addition to a regular sample, a spare sample is held in a loading chamber in which a sample is kept in a vacuum state for waiting. CONSTITUTION:One sample exclusively for cleaning is placed on each one of the sample holding cassettes in loading chambers 43 and 47 beforehand. Then 25 regular samples to be treated in a cassette placed on a cassette stage 40 are transferred to an orientation flat aligning mechanism 41 by a conveying robot 42a and the orientation flats are aligned with each other. After that, the 25 regular samples are again transferred to the sample holding cassette in the loading chamber 43 by the conveying robot 42a and housed. As a result, 25 regular samples to be treated and one sample exclusively for cleaning are housed in the sample holding cassette. Then the loading chamber 43 is evacuated and one of the regular samples is transferred to the sample table of an ECR apparatus 45.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a cleaning method for the same, and more particularly to a CVD method for a sample.
Plasma processing device for performing processing and etching processing,
The present invention also relates to a cleaning method for a plasma processing apparatus, which removes particles, deposits and the like in a reaction chamber by plasma etching.

[0002]

2. Description of the Related Art FIG. 3 shows an electron cyclotron resonance (ECR) generally used in a method for forming a thin film.
FIG. 3 is a cross-sectional view schematically showing an apparatus (hereinafter, referred to as an ECR apparatus) that generates plasma by on-resonance) and performs plasma processing.

The ECR apparatus comprises an apparatus body 13 including a plasma generation chamber 11 and a reaction chamber 12, and a plasma generation chamber 1
1. An exciting coil 14 which is arranged around 1 and to which a DC power source (not shown) is connected, and a waveguide 15 which introduces microwaves oscillated from a microwave oscillator (not shown) into the plasma generation chamber 11. Etc. 16 is a microwave introduction window, 17 is a high frequency (R
F) applying a high frequency source, 18 is a sample table on which the sample 19 is placed, 50 is the sample table 18 fixed on the sample table 18, and deposits, particles and the like are attached to the sample table 18. The quartz holding rings for prevention are shown respectively.

The plasma generation chamber 11 is formed in a substantially cylindrical shape, and a first hole 20 for introducing a microwave is formed in a substantially central portion of an upper wall of the plasma generation chamber 11, and the plasma generation chamber 11 is formed. A reaction chamber 12 having a larger diameter than the plasma generation chamber 11 is integrally formed below the plasma generation chamber 11. Further, the reaction chamber 12 and the plasma generation chamber 1
1 is partitioned by a partition plate 21, and a second hole (plasma lead-out window) 22 is provided at a substantially central portion of the partition plate 21.
Are formed.

Further, a first introducing pipe 23 is connected to the side wall of the reaction chamber 12, and an exhaust pipe 24 communicating with an exhaust system (not shown) is connected to the bottom of the reaction chamber 12. A second introduction pipe 25 is connected to the upper wall of the plasma generation chamber 11.

The high frequency generator 17 is composed of a high frequency generator 26 and a matching box 27, and a microwave introducing window 16 is interposed via a plate electrode 28 sandwiched between the microwave introducing window 16 and the waveguide 15. A high frequency is applied to.

A high frequency oscillator 31 for applying a high frequency to the sample 19 is provided on the sample table 18 and a matching box 30 is provided.
Connected through. By applying a predetermined high frequency to the sample 19 by the high frequency oscillator 31 to form a thin film, a bias voltage applied to the sample 19 forms a thin film having good step coverage even when the uneven surface of the sample 19 is minute. Can be formed.

FIG. 4A is an enlarged plan view schematically showing the vicinity of the sample table 18, and FIG. 4B is an enlarged front sectional view thereof. The quartz pressing ring 50 is formed in a ring shape, and quartz pressing pins 50a for pressing the sample 19 to the sample table 18 are formed at three protruding portions inside the ring. Pin 50
The sample 19 pressed by a is placed on the sample table 18.

To form, for example, a TiN thin film using the above apparatus, first the exhaust system is operated to depressurize the inside of the apparatus main body 13, and then TiCl ₄ is introduced into the reaction chamber 12 from the first introducing pipe 23. Supply. On the other hand, Ar, H ₂ , and N ₂ are supplied into the plasma generation chamber 11 through the introduction pipe 25. Then, the inside of the apparatus main body 13 is set to a predetermined pressure.

Further, the high frequency generator 17 is energized to apply a high frequency to the microwave introducing window 16, and the microwave introducing window 1
The TiN thin film is prevented from adhering to the microwave introducing window 16 by the sputtering effect of Ar ions due to the bias voltage generated at 6. On the other hand, a microwave is introduced into the plasma generation chamber 11 from the microwave oscillator through the waveguide 15, and a direct current is passed through the exciting coil 14 to generate a magnetic field in the plasma generation chamber 11. Then, high-energy electrons collide with the raw material gas in the plasma generation chamber 11, and the raw material gas is decomposed and ionized to generate plasma.

The generated plasma passes through the hole 22, is accelerated by the divergent magnetic field in the direction of arrow A in the figure and is guided into the reaction chamber 12, and the TiN thin film is formed on the surface of the sample 19 placed on the sample table 18. To form.

Next, using the above ECR device, sample 19
A procedure for continuously performing plasma processing on the will be described. FIG. 5 is a plan view schematically showing a plasma processing apparatus in which two ECR devices each having the configuration shown in FIG. 3 are arranged.
The cassette stage 40 is a table on which a cassette containing, for example, 25 samples 19 for plasma processing is placed. The sample 19 in the cassette set on the cassette stage 40 is transferred to the orientation flat alignment mechanism 41 by the transport robot 42a, and the orientation flat is aligned. After that, the sample 19 is again transported into the loading chamber 43 by the robot 42a. The loading chamber 43 is equipped with a sample holding cassette (not shown), and 25 samples 19 are stored in the sample holding cassette of the loading chamber 43 by the robot 42a.

Next, the loading chamber 43 is evacuated,
First, one of the samples 19 in the loading chamber 43 is transferred by the robot 42b to the sample stage 18 of the plasma processing apparatus 45 (or the plasma processing apparatus 46) through the transfer chamber 44, and plasma processing is performed by the method described above. It During the plasma treatment, the other sample 19 is not plasma-treated by the robot 42b.
The sample is transferred to the sample table 18 in the CR device 46 (or the ECR device 45) and similarly plasma-processed. When the plasma processing in the ECR device 45 is completed, the sample 19 is transferred to the original sample holding cassette in the loading chamber 43, and a new sample 19 is transported to the ECR device 45. Thereafter, the ECR device 45 or the ECR device 4 is operated by the same operation.
Samples 19 are successively transferred to 6, and after being subjected to plasma treatment, they are transferred to the original sample holding cassette. After the plasma treatment is completed for all 25 samples 19 and all the samples 19 are stored in the sample holding cassette, the loading chamber 43 is isolated from the transfer chamber 44,
After returning to atmospheric pressure, the sample 19 is transported to the first cassette stage 40 by the robot 42a, and a series of processing is completed.

Here, the loading chambers 43 and 47, the transfer chamber 44, and the ECR devices 45 and 46 are all constructed so that they can be evacuated, so that the sample 19 is transferred to the loading chamber 43 (47) and then plasma is transferred. There is no direct contact with the atmosphere until the process is completed and the loading chamber 43 (47) is exited.

On the other hand, while the above process is in progress, 25 unprocessed samples 19 from the next cassette stage 48 are transferred to the orientation flat aligning mechanism 41 by the transfer robot 42a to align the orientation flats, and another It is conveyed to the sample holding cassette in the loading chamber 47. And
When all the samples 19 that have undergone the plasma treatment in the above process are completely stored in the sample holding cassette in the loading chamber 43, they can be transported from another loading chamber 47 to the ECR devices 45 and 46. Therefore, after that, the sample 19 is transported to the ECR devices 45 and 46 in the same manner as in the above method, plasma-treated, and the processed sample 19 is loaded into the loading chamber 47.
The sample is transferred to the original sample holding cassette. All samples 1
After 9 is returned to the loading chamber 47 by the robot 42b, the loading chamber 47 is returned to the atmospheric pressure, and this time the sample 19 is returned to the first cassette stage 48 by the robot 42a, and a series of processing is completed.

[0016]

Normally, when plasma processing is performed to form a thin film on the sample 19, deposits, particles and the like are also deposited in the reaction chamber 12. This reaction chamber 12
Plasma cleaning is regularly performed to remove deposits, particles, and the like inside. As the plasma cleaning method, a highly corrosive fluorine-based gas is introduced through the first introduction pipe 23, and plasma is irradiated for about 10 minutes to perform cleaning. At this time, the reaction chamber 12
Since not only the inner wall of the sample table 18 but also the sample table 18 are irradiated with the etching plasma, the sample table 18 is etched and sputtered, and the heater (not shown) embedded in the sample table 18 and the sample table 18 18 The surface is damaged. However, since it is difficult to remove and clean the sample table 18, the surface morphology of the sample table 18 deteriorates, the contact area with the sample 19 changes, and the reproducibility of the process is lost. .

Further, since the sample table 18 is etched and sputtered, the etching product from the sample table 18 is deposited on the inner wall of the reaction chamber 12, and during the film forming process on the sample 19,
There is also a problem that heavy metal contamination or the like occurs or the number of particles remaining on the processed sample 19 increases.

The present invention has been made in view of the above problems, and the reaction chamber can be easily cleaned without damaging the sample stage, and metal contamination or particles of the sample to be subjected to the plasma treatment after that can be cleaned. An object of the present invention is to provide a plasma processing apparatus capable of preventing an increase in the number and a cleaning method thereof.

[0019]

In order to achieve the above object, a plasma processing apparatus according to the present invention comprises a reaction chamber for carrying out plasma processing, which is equipped with a sample table on which a sample is placed, and a reaction chamber in the reaction chamber. Alternatively, in a plasma processing apparatus having a loading chamber for continuously waiting the sample conveyed from the reaction chamber in a vacuum state, a sample holding means for holding a preliminary sample together with a regular sample is provided in the loading chamber. It is characterized by (1).

The cleaning method of the plasma processing apparatus according to the present invention is the same as the cleaning method of the plasma processing apparatus described in (1) above, except that the sample holding means for the preliminary sample in the loading chamber has the same shape as the regular sample. A cleaning sample, the cleaning sample is conveyed onto a sample table in the reaction chamber, and plasma is generated in the reaction chamber while the cleaning sample is placed on the sample table to plasma-clean the reaction chamber. After that, the cleaning sample is returned to the sample holding means portion for the preliminary sample in the loading chamber (2).

Further, the cleaning method of the plasma processing apparatus according to the present invention is the same as the cleaning method of the plasma processing apparatus described in (2) above, except that the sample holding means for the preliminary sample in the loading chamber has the same shape as the regular sample. It is characterized in that a cleaning sample having a shape smaller than the regular sample is provided in place of the cleaning sample (3).

[0022]

According to the plasma processing apparatus described in (1) above,
A reaction chamber for performing a plasma treatment provided with a sample table on which a sample is placed, and a loading chamber for keeping a sample transferred into or out of the reaction chamber in a vacuum state for successive standby Since the plasma processing apparatus is provided with the sample holding means for holding the preliminary sample together with the regular sample in the loading chamber, the plasma processing apparatus is used to clean the plasma processing apparatus according to (2) or (3) above. The method can be carried out, and the sample stage is protected from corrosion by plasma during cleaning.

According to the method described in (2) above, in the cleaning method of the plasma processing apparatus described in (1) above, the cleaning sample having the same shape as the regular sample is provided in the sample holding means portion for the preliminary sample in the loading chamber. And transporting the cleaning sample onto a sample table in the reaction chamber, plasma is generated by generating plasma in a state where the cleaning sample is placed on the sample table, and then the plasma is cleaned in the reaction chamber. Since the cleaning sample is returned to the sample holding means portion corresponding to the preliminary sample in the loading chamber, the cleaning sample is placed on the sample table at the time of cleaning the apparatus after the plasma processing of the regular sample, and at the time of cleaning. The sample table is protected from the plasma in the above, and the sample table is not damaged. , It is possible to clean a plasma processing apparatus.

According to the method described in (3) above, in the cleaning method of the plasma processing apparatus described in (2) above, the sample holding means portion for the preliminary sample in the loading chamber is for cleaning the same shape as the regular sample. Since a cleaning sample having a shape smaller than the regular sample is equipped instead of the sample, particles and deposits on the sample table adhered between the regular sample and the quartz holding ring by the plasma treatment of the regular sample. Can be cleaned without damaging the sample table.

[0025]

EXAMPLES Examples of a plasma processing apparatus and a cleaning method therefor according to the present invention will be described below. The configuration of the plasma processing apparatus according to the embodiment is the same as that of the conventional apparatus shown in FIGS. 3 and 5, except for the sample holding cassette. Therefore, only the sample holding cassette will be described here, and description of the configuration of other devices will be omitted. FIG. 1A is a plan view schematically showing a sample holding cassette according to an embodiment of the present invention, and FIG. 1B is a front view thereof.

The sample holding cassette 35 made of Ti contains 2
Six levels of sample mounting shelves 36 are formed, and an upper sample protection member 37, which is a flat plate member slightly larger than the sample, is disposed above the sample mounting shelf 36. Also,
A cassette raising / lowering member 38 is attached to the lower portion of the sample holding cassette 35, and when the robot 19 conveys the sample 19, the cassette raising / lowering member 38 keeps the sample holding cassette 35 at an appropriate height. Adjusted. Conventionally, only the normal processing sample 19 to be subjected to the plasma processing needs to be mounted, so that the sample mounting shelf has 25 shelves, but in the present embodiment, a cleaning-dedicated sample is mounted in addition to the normal processing sample 19. It is necessary to place the sample placing shelves 36 for that purpose in 26 stages. Since the sample holding cassette 35 having such a configuration is used, the plasma processing apparatus described below can be cleaned.

In the cleaning method of the plasma processing apparatus according to the embodiment, first, the cleaning-dedicated samples are placed one by one on the sample holding cassettes 35 in the loading chambers 43 and 47, respectively. Next, the 25 normal processing samples 19 in the cassette set on the cassette stage 40 are transferred to the orientation flat alignment mechanism 41 by the transfer robot 42a, and the orientation flats are aligned. After that, the sample 42 is again transported to the sample holding cassette 35 in the loading chamber 43 by the robot 42a, and 25 normal processed samples 19 are stored therein. By this operation, 25 normal processing samples 19 and one cleaning-dedicated sample are stored in the sample holding cassette 35.

Next, the loading chamber 43 is evacuated,
First, one of the regular processed samples 19 in the loading chamber 43 is transferred to the sample stage 18 of the ECR device 45 by the robot 42b through the transfer chamber 44, and plasma processing is performed. During the plasma processing, the other regular processing sample 19 is carried by the robot 42b into the ECR device 46 which is not plasma-treated, and is similarly plasma-treated. When the above processing in the ECR device 45 is completed, the normal processing sample 19 is transferred to the original sample holding cassette 35 in the loading chamber 43, and a new normal processing sample 19 is transferred to the sample table 18 of the ECR device 45.
After that, by the same operation, the regular processed samples 19 are successively transferred to the ECR device 45 or the ECR device 46, subjected to plasma processing, and then transferred to the original sample holding cassette 35. After the plasma processing has been completed for all 25 normal processing samples 19 and all the normal processing samples 19 have been stored in the sample holding cassette, this time, a cleaning-dedicated sample passes through the transfer chamber 44 and then the sample of the ECR device 45. The gas is placed on the table 18, the supplied gas is changed from the film-forming gas to the corrosive fluorine-based gas for cleaning, and the fluorine-based gas is introduced into the reaction chamber 12 through the first introduction pipe 23 to generate plasma. Cleaning is performed. In this way, after the plasma cleaning is performed with the sample dedicated to cleaning placed on the sample table 18, the sample dedicated to cleaning is returned to the original sample holding cassette 35. After this, the loading chamber 43 is transferred to the transfer chamber 4
After being separated from No. 4 and returned to atmospheric pressure, 25 sheets of the regular processing sample 19 are transferred to the first cassette stage 40 by the robot 42a, and a series of processing is completed. At this time, the cleaning-dedicated sample remains in the sample-holding cassette 35 as it is, and when the ECR devices 45 and 46 are cleaned again, the same cleaning-dedicated sample is used. This cleaning-dedicated sample can be the same until it needs to be replaced with a new one.

On the other hand, while the above steps are in progress, 25 unprocessed regular processed samples 19 from the next cassette stage 48 are transferred to the orientation flat aligning mechanism 41 by the transport robot 42a, and the orientation flats are aligned and separated. It is conveyed to the sample holding cassette 35 in the loading chamber 47 of FIG. Then, the regular processing sample 1 that has been subjected to the plasma processing in the above step
9 is a sample holding cassette 35 in the loading chamber 43
When the transfer is completed, the transfer from another loading chamber 47 to the ECR devices 45 and 46 becomes possible. Therefore, after that, the regular processed sample 19 is the ECR device 45, as in the above process.
The processed normal processed sample 19 is transferred to the original sample holding cassette 35 in the loading chamber 47. After all the regular processed samples 19 are stored in the sample holding cassette 35 of the loading chamber 47 by the robot 42b, the sample dedicated to cleaning is transported to the sample table 18 in the same manner as the above case, and the fluorine-based gas is introduced. Then, cleaning is performed. After the cleaning is completed, the other 25 normal processing samples 19 are returned to the first cassette stage 48 by the robot 42a, leaving a sample dedicated to cleaning, and the series of processing is completed. The cleaning process is not necessarily performed after the plasma processing of 25 normal processed samples 19 is completed, and may be performed only once for every 50 or 100 samples.

Next, a method of cleaning the plasma processing apparatus according to another embodiment will be described. In the plasma processing apparatus cleaning method according to another embodiment, the sample holding cassette 35 provided in the loading chambers 43 and 47 is used.
In addition, exactly the same steps as those in the above-described embodiment are repeated except that one cleaning-specific sample having a shape smaller than the regular processed sample 19 is stored in advance. Therefore, a detailed description of this embodiment will be omitted here.

[Example 1 and Comparative Example 1] Next, as a specific example and comparative example, when a cleaning-dedicated sample was placed on the sample table 18 when performing cleaning by the above method (Example 1) ) And a case where cleaning is performed without placing a sample dedicated to cleaning on the sample table 18 (Comparative Example 1), the sample after cleaning (silicon wafer)
Experiments were conducted on how different the degree of 19 metal contamination was.

The method is to perform the cleaning treatment of the plasma treatment apparatus under the above-mentioned two different conditions, and immediately thereafter, form the TiN thin film on the silicon wafer in the same manner as the method described in "Prior Art". How much Fe was present on the surface of the silicon wafer was measured by a fluorescent X-ray analysis method.

In the cleaning process, NF ₃ is used as a cleaning gas, and the cleaning pressure is 1 mTorr.
r, high frequency applied to microwave introduction window (13.56M
High frequency (13.5 Hz) of 150 W applied to the sample stage.
6 MHz) to 500 W, microwave (2.45 GHz)
Is set to 2.8 kW and the sample stage temperature is set to 500 ° C.
It was carried out under the condition of applying microwave for a minute. Further, the TiN thin film after that has TiCl ₄ ::
The flow rate ratio of N ₂ : H ₂ : Ar is 15 sccm: 10 scc.
m: 50 sccm: 43 sccm, the reaction pressure was 1 mTorr, the high frequency (13.56 MHz) applied to the microwave introduction window was 150 W, the microwave (2.45 GHz) was 2.8 kW, and the sample table temperature was Fifty
It was performed under the condition that the temperature was set to 0 ° C. and the microwave was applied for 5 minutes.

The amount of Fe present on the surface of the silicon wafer obtained by the above treatment was measured by a fluorescent X-ray analysis method. As a result, the amount of Fe present on the surface of the silicon wafer according to Example 1 was 12 × 10 ¹⁰ pieces / cm ^2. However, Comparative Example 1
The amount of Fe present on the surface of the silicon wafer is 150 × 1
It was found that the number was as high as 0 ¹⁰ pieces / cm ^2, and it was found that the metal contamination of the silicon wafer can be prevented by placing the cleaning-dedicated sample on the sample table for cleaning.

[Examples 2 and 3 and Comparative Example 2] Next, a continuous experiment for investigating how the degree of adhesion of particles to the sample 19 is different when cleaning is performed and when it is not performed is described. went. That is, when the normal processing sample (silicon wafer) 19 is processed by the same method as that described in the above-mentioned embodiment except that the cleaning is not performed (Comparative Example 2), the sample having the same size as the silicon wafer is used as the cleaning-specific sample. Is used (Example 2),
Also, when a sample having a shape slightly smaller than that of the silicon wafer was used as the cleaning-dedicated sample (Example 3), it was examined how the number of particles on the silicon wafer differed.

First, in Examples (Examples 2 and 3), CVD processing (formation of TiN thin film) on silicon wafers was performed on 100 silicon wafers, and then cleaning treatment was performed once. Was processed by the same method as the method described in the above example, and in Comparative example 2, 400 sheets were processed without performing the cleaning treatment, and the number of particles on the silicon wafer was measured every 50 sheets.

The conditions for the cleaning process and the conditions for forming the TiN thin film are the same as in the case of Example 1 and Comparative Example 1 above. FIG. 2 is a graph showing the results of the above measurement, in which the vertical axis represents the number of particles having a diameter of 0.3 μm or more existing on a 6-inch silicon wafer, and the horizontal axis represents the number of silicon wafers subjected to CVD treatment. There is.

As is clear from the results shown in FIG. 2, when the cleaning process is not performed (Comparative Example 2), 200
It can be seen that the number of particles sharply increases from the time of processing the sheets, and that various deposits that cause particles are cumulatively increased in the plasma processing apparatus unless the cleaning process is performed. On the other hand, as can be seen from the results in the case of the embodiment, since the deposit that causes particles can be removed by performing the cleaning process regularly, the increase of particles is small, but the sample dedicated to cleaning is a silicon wafer. In the case of the same size (Example 2), since the deposits gradually increase on the portion of the sample table 18 on which the silicon wafer is placed, the particles gradually increase after the processing of 450 wafers. is doing. On the other hand, when a sample slightly smaller than the silicon wafer is used as a sample dedicated to cleaning (Example 3), most of the deposits on the sample stage are removed by the cleaning process, and the number of particles is not increased at all.

As described above, in the cleaning method of the plasma processing apparatus according to the embodiment, in addition to the regular processing sample 19 to be processed in advance in the sample holding cassette 35, it is placed on the sample table 18 during plasma cleaning. Since a cleaning sample having the same shape as that of the regular processing sample 19 to be placed is provided, the gas supplied to the reaction chamber 12 after the plasma processing of the regular processing sample 19 is corrosive from the gas for film formation. Even if the fluorine-based gas for cleaning is changed and the fluorine-based gas is used to plasma-clean the reaction chamber 12, the cleaning can be performed easily without damaging the surface of the sample table 18 in which the heater is embedded. it can.

Further, in addition to the regular processed sample 19 to be processed in advance, the sample holding cassette 35 was equipped with a sample having a shape smaller than that of the regular processed sample 19 to be mounted on the sample stage 18 during plasma cleaning. In this case, after the plasma processing of the regular processed sample 19 is completed, the gas supplied to the reaction chamber 12 is changed from the film forming gas to a corrosive cleaning fluorine-based gas, and when the plasma cleaning of the reaction chamber 12 is performed, It is possible to remove particles and deposits attached to the gap between the regular processing sample 19 and the quartz pressing ring 50 during the plasma processing of the regular processing sample 19 without damaging the surface of the sample table 18.

[0041]

As is apparent from the above description, in the plasma processing apparatus according to the present invention, the reaction chamber for performing the plasma processing provided with the sample table on which the sample is placed, and the reaction chamber Alternatively, in a plasma processing apparatus having a loading chamber for continuously waiting the sample conveyed from the reaction chamber in a vacuum state, a sample holding means for holding a preliminary sample together with a regular sample is provided in the loading chamber. Therefore, using the plasma processing apparatus described above (2)
Alternatively, the plasma processing apparatus cleaning method described in (3) can be implemented, and the sample stage can be protected from corrosion and the like caused by plasma during cleaning.

Further, in the plasma processing apparatus cleaning method according to the present invention, in the plasma processing apparatus cleaning method described in (1) above, the sample holding means portion for the preliminary sample in the loading chamber is the same as the regular sample. A cleaning sample having a shape is provided, the cleaning sample is conveyed onto a sample table in the reaction chamber, and plasma is generated in the reaction chamber while the cleaning sample is placed on the sample table. After cleaning, the cleaning sample is returned to the sample holding means portion corresponding to the preliminary sample in the loading chamber. Therefore, after the plasma processing of the regular sample, the gas supplied to the reaction chamber is corrosive from the film forming gas. Change to a fluorine-based gas for cleaning, and the fluorine-based gas cleans the plasma of the reaction chamber. It is rope, without damage to the sample stage surface where the heater is embedded, it is possible to easily perform cleaning.

Further, in the cleaning method of the plasma processing apparatus according to the above (2), instead of the cleaning sample having the same shape as the regular sample in the sample holding means portion for the preliminary sample in the loading chamber, a shape smaller than the regular sample is used. In the case where the cleaning sample is installed, after the plasma treatment of the regular sample, the gas supplied to the reaction chamber is changed from the film forming gas to the corrosive fluorine-based gas for cleaning, and the plasma cleaning of the reaction chamber is performed. When performing, the particles and deposits adhering between the regular sample and the quartz pressing ring can be cleaned without damaging the surface of the sample table.

[Brief description of drawings]

1A is a plan view schematically showing a sample holding cassette according to an embodiment of the present invention, and FIG. 1B is a front view thereof.

FIG. 2 shows the number of processed silicon wafers and the number of particles when a cleaning method of a plasma processing apparatus according to an example is performed (Examples 2 to 3) and when the cleaning method is not performed (Comparative example 2). It is a graph showing the relationship of.

FIG. 3 is a schematic cross-sectional view showing an example of an ECR device.

FIG. 4A is an enlarged plan view schematically showing the vicinity of a sample stand of an ECR device, and FIG. 4B is an enlarged front sectional view thereof.

FIG. 5 is a plan view schematically showing a plasma processing apparatus provided with two ECR apparatuses.

[Explanation of symbols]

 12 reaction chamber 18 sample stage 19 sample (normally processed sample) 43, 47 loading chamber

Claims (3)

[Claims] 1. A reaction chamber for performing a plasma treatment, which comprises a sample table on which a sample is placed, and a loading for holding a sample transferred into or out of the reaction chamber in a vacuum state. A plasma processing apparatus comprising a chamber, and a sample holding unit for holding a preliminary sample together with a regular sample in the loading chamber. 2. A cleaning sample having the same shape as the regular sample is provided in a sample holding means portion for the preliminary sample in the loading chamber, and the cleaning sample is conveyed onto a sample table in the reaction chamber for cleaning. Plasma is generated in a state where the sample is placed on the sample table to plasma-clean the reaction chamber, and then the cleaning sample is returned to the sample holding means portion of the preliminary sample in the loading chamber. The method for cleaning a plasma processing apparatus according to claim 1. 3. The cleaning sample having a shape smaller than the regular sample is provided in the sample holding means portion for the preliminary sample in the loading chamber, instead of the cleaning sample having the same shape as the regular sample. 2. The method for cleaning a plasma processing apparatus according to 2.