JPH0786241A - Vacuum processing method and device - Google Patents

Abstract

(57) [Summary] [Object] The present invention efficiently cleans the interior of a vacuum processing apparatus such as a sputtering apparatus, a CVD apparatus, or an etching apparatus without exposing the vacuum processing chamber to the outside air containing water, and the operation rate of the apparatus is improved. The purpose is to increase significantly. [Structure] The vacuum processing chamber 1 and the lower vacuum chamber 6 are provided with cleaning gas introduction ports 12 and 24, a gas discharge duct 17 and a movable electrostatic precipitator 14. After the vacuum process is completed, dry gas at atmospheric pressure level is introduced to lift up foreign matter in the reaction chamber or vacuum chamber and put on a gas flow to remove it from the exhaust duct to the outside of the equipment, or an appropriately placed electric Let the dust collector capture it. Furthermore, during the cleaning with the dry gas described above,
The reaction chamber is returned to vacuum again, a plasma for cleaning is set up in the reaction chamber to desorb the reaction products on the wall surface by the plasma, and the dusted products are removed again by introducing and discharging the dry gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum processing method and apparatus, and more particularly to a vacuum processing suitable for forming a thin film by sputtering, CVD or the like under vacuum, or for fine processing of the surface such as etching and ion implantation. The present invention relates to a method and an apparatus.

[0002]

2. Description of the Related Art As a conventional technique for removing a reaction product of a vacuum processing apparatus without breaking the vacuum of a processing chamber, there are Japanese Patent Laid-Open Nos. 61-216327 and 63-1.
No. 26225, JP-A-1-115123, JP-A-1-115123, and JP-A-2-94522, plasma is generated in the processing chamber separately from the vacuum processing of the substrate. There is a method to remove the deposits.

As an example of a conventional technique having a dust collecting function in a vacuum processing chamber, there is JP-A-3-127831. There is also an example in which a centrifugal dust collector is placed between the processing chamber and the vacuum exhaust pump system as in JP-A-60-28849. Further, as an example of a conventional technique in which a gas is introduced into a vacuum processing chamber and then cleaning is performed, there are JP-A-63-1035 and JP-A-2-50423. All of these technologies are designed to leak gas, raise dust, and exhaust it to the vacuum pump side to remove foreign matter.

[0004]

However, in the above-mentioned conventional technique, the effect of removing foreign matters from the processing chamber is small only by generating the plasma for cleaning in the processing chamber and separating the deposited deposit from the wall surface. The detached deposits may float due to the electric force of the plasma, or may be transferred to the vacuum pump side due to the gas flow, but the transfer force is weak because it is originally a vacuum atmosphere, and most of the detached foreign matter. Remains in the processing chamber and has not been cleaned.

Further, as in another conventional technique, it is not possible to collect reaction products generated in the processing chamber and deposits deposited on the wall surface simply by providing the function of electrostatic dust collection,
After all, the reaction product generated in the processing chamber remains in the processing chamber as it is, and the cleaning effect is small.

Further, as in another prior art, even if foreign matter soars, the pressure that can be used for using the vacuum pump is at a level much lower than atmospheric pressure, and the force for eliminating foreign matter is weak. The reaction products adhering to the processing chamber are not desorbed by a slight gas leak, and the cleaning effect of the processing chamber is small. As described above, according to the conventional technique, it is difficult to clean the vacuum processing chamber while maintaining the vacuum.

Generally, in a vacuum processing apparatus, a thin film is formed on the substrate surface or the substrate is etched by plasma, radicals or thermally active gas molecules in the reaction processing chamber. At this time, the reaction products are deposited on the wall surface of the reaction processing chamber other than the substrate and the surface of the internal parts, or conversely, the surface is etched.
The reaction products formed in these reaction chambers are deposited as dust or foreign matters throughout the vacuum processing apparatus. These foreign substances are the main cause of product defects in the processing process requiring fine processing such as a substrate for LSI. Therefore, in order to prevent processing defects in vacuum processing equipment,
It is necessary to periodically shut down the apparatus, open the reaction chamber, remove the accumulated reaction products and foreign substances, and clean it. Generally, it takes a long time to carry out the cleaning and subsequent start-up of the apparatus, condition setting for processing, etc., which is the biggest obstacle in improving the operation rate of the vacuum processing apparatus. Also, exposing the reaction chamber to an atmosphere containing water after every cleaning may be an obstacle to returning the vacuum processing condition after restarting to the original condition even in a short time, which is one of the causes of the lowering of the operating rate. ing.

It is an object of the present invention to efficiently clean the vacuum processing apparatus and shorten the total cleaning time, thereby significantly increasing the operation rate of the apparatus.

[0009]

The first means for achieving the above-mentioned object is to clean the vacuum processing chamber while maintaining it in vacuum. The second means is to clean the vacuum processing chamber without exposing it to the outside air. The third means is to provide a functional means for collecting foreign matter in the reaction chamber in the reaction chamber. The fourth means is to wind up foreign matter, which has become fine dust and has accumulated in the reaction chamber, into the space by introducing an inert and dry gas, and to put the foreign matter on the gas flow to the outside of the processing apparatus through the exhaust port. It is a method of removing. Fifthly, an electric dust collector is provided in the gas flow path near the exhaust port. The sixth is such that an exhaust port for exhausting the dry gas introduced by the method described in the fourth is provided on the upstream side of the inlet valve of the vacuum pump. The seventh method is a method in which the reaction product deposited on the wall surface is peeled off from the wall surface by hitting it with plasma, and this is carried on the air flow of the dry gas to be guided to the exhaust port and removed to the outside. The eighth is to monitor the formation state of reaction products on the inner wall surface from the outside of the processing chamber and automatically clean the reaction product as necessary.

[0010]

[Function] When cleaning the vacuum processing chamber, if the vacuum is maintained without breaking the vacuum, the vacuum startup time after cleaning becomes unnecessary, and the reaction chamber is exposed to the atmosphere containing water. Therefore, the processing conditions can be set in a short time. Assuming that a gas at atmospheric pressure level is used for cleaning, if a dry inert gas or nitrogen is used, the reaction chamber will not be exposed to the atmosphere containing water. You will be able to do it in. By providing a dust collecting function in the vacuum processing chamber, the processing chamber can be cleaned without being exposed to the atmosphere. When cleaning is required, an inert, dry gas is blown into the vacuum processing chamber to flow out from the exhaust port side, and foreign matter that has become fine dust and accumulated in the reaction chamber is rolled up into the space, Remove to the outside of the vacuum processing unit along with the flow. As a result, it is possible to remove the foreign matter deposited inside the processing chamber without exposing it to the atmosphere containing water. If you install a dust collector near the exhaust port, you can more effectively remove foreign matter from the air stream. Also, if a dry exhaust gas with an atmospheric pressure level is used as an exhaust port and not a vacuum pump, but another exhaust port with a valve is installed on the upstream side of the pump inlet side valve, the vacuum pump can be disconnected when the dry gas is introduced and cleaned. Can be set.

At the time of cleaning, first, a plasma for cleaning is raised to separate the reaction products firmly adhered to the wall surface and the like, and then a dry inert gas is blown into the separated dust to entrain it in the air stream. , Can be removed from the device together with the air flow from the exhaust port.

By monitoring the state of the inside of the vacuum processing chamber, it becomes possible to always judge the necessity of cleaning and it becomes possible to perform automatic cleaning at the most suitable timing.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, which is an example of a magnetic field microwave plasma etching apparatus.
In FIG. 1, 1 is a reaction processing chamber, 2 is a quartz bell jar that forms the reaction processing chamber, 3 is a magnet that gives a magnetic field to the reaction chamber,
4 is a magnetron, 5 and 50 are microwave waveguides,
6 is a lower vacuum chamber, 21 is a base flange, 7 is an electrode,
The wafer 8 is placed on this during processing. 9 is an exhaust duct, 20 is a vacuum valve, 10 is a vacuum pump, 11 is an etching gas supply port, 23 is an etching gas cylinder,
12, 24 is a dry gas inlet for cleaning, 13 is a dry gas for cleaning, 14-1, 14-2, 14-3 are vertically movable electrostatic precipitators, 15 is a high frequency power source for the electrodes, and 16 is a roughing vacuum. The pump 17 is an exhaust duct for cleaning gas. The electrode 7 and the electrostatic precipitator 14 are movably sealed between the vacuum and the atmosphere by the seal portions 18 and 19-1, 19-2, and can be moved in the vertical direction. FIG. 2 is a sectional view taken along the line II-II in FIG. 1 (a sectional view of the reaction treatment chamber from above). A plurality of electrostatic precipitators 14 are provided, and a plurality of dry gas inlets 12 are provided so as to face the electrostatic precipitators 14. -1, 12-2, 12-3 are provided.

In this apparatus, a normal etching process is first performed. That is, the reaction chamber 1 is evacuated to a vacuum by the operation of the vacuum pumps 10 and 16, the magnetic field is then applied by the magnet 3, and the etching gas is introduced into the vacuum chamber from the introduction port 11, and the magnetron 4 is operated to activate the microwave. Is guided from the waveguide 5 to the reaction chamber 1 and ignites plasma. A wafer 8 is placed on the electrode 7. An appropriate plasma is formed by adjusting the strength of the microwave or magnetic field, the flow rate of the etching gas, the pumping speed of the pump, the strength of the high frequency, etc. By this action, the wafer 8 is finely processed. When the predetermined processing is completed, the plasma is stopped once, the wafer is carried to the preparation chamber (not shown) while being load-locked to the vacuum, and the next wafer is carried onto the electrode instead. The plasma is ignited again and the next processing is performed. In this way, in the vacuum processing chamber, wafers are successively etched and exchanged while maintaining the vacuum in a so-called single wafer system. By the way, a reaction product is formed in the reaction chamber every time the etching process is performed. Some of these are exhausted from the exhaust duct 9 to the outside of the system by the vacuum pump 10, but some become minute solid foreign matters and the inner wall surface of the vacuum chamber 6 and the electrodes 7.
It sticks out or adheres to the surface of. When the etching process is repeated, foreign substances due to this reaction product are accumulated more than the limit. When the accumulation of reaction products exceeds the limit,
Stop etching, do not open the processing chamber to the atmosphere,
The vacuum valve 20 is closed, and an inert dry gas such as nitrogen from which water has been removed is blown into the processing chamber and the lower vacuum chamber through the inlets 12 and 12-2. The pressure may be at atmospheric pressure level. The foreign matter accumulated on the wall surface and the surface of the electrode is rolled up by this gas. If the electrostatic precipitator 14 is operated at the same time when the dry gas is blown in, foreign matter wound up in the dry gas is captured by the electrostatic precipitator 14. It should be noted that when the reaction chamber becomes atmospheric pressure or more in accordance with the introduction of the dry gas, the valve 22 is opened to discharge the dry gas from the exhaust duct 17 to the outside of the room. The electrostatic precipitator 14 is movable in the vertical direction so that it can be brought to a position effective for capturing foreign matter. For example, it is usually housed in the lower vacuum chamber, but when cleaning is started, it moves to the upper side,
Bring it like electrode 7. Alternatively, the electrode 7 may be lowered. In this way, the dry gas introduced from the cleaning dry gas inlet 12 directly contacts the surface of the electrode, and as shown in FIG. 2, the electrostatic precipitator 14 is opposed to the direction of the dry gas introduced. With this arrangement, the foreign matter wound up in the dry gas is efficiently captured by the electrostatic precipitator 14. Further, it is also effective to dispose the inlet of the dry gas near the bottom surface like 24 in order to easily wind up the foreign matter in the lower vacuum chamber in which the foreign matter is easily accumulated. If such a cleaning operation is continued, the foreign matter inside can be removed without exposing the vacuum processing chamber to the outside air. Cleaning time can be shortened because it is not necessary to open the reaction chamber. Since the gas to be introduced is an inert dry gas that does not contain water even at the atmospheric pressure level, the vacuum startup after cleaning can be performed in a very short time. Further, since water has not entered, the etching processing conditions after the start-up are the same as those before the cleaning, so that the etching processing with good reproducibility can be realized. In this way, the cleaning time and the startup time for the subsequent etching process can be greatly shortened, so that the operating rate of the etching apparatus can be dramatically improved.

Depending on the type, it may be difficult to remove the reaction product adhering to the processing chamber only by blowing dry gas. In such a case, the introduction of the dry gas is stopped once, the vacuum pump is operated to evacuate the processing chamber, and a microwave is introduced from the waveguide 5 while introducing a small amount of the dry gas to generate plasma. It is also an effective method that the product adhered to the wall surface is detached from the wall surface. In this case, after applying plasma for an appropriate time, the vacuum valve 20 again separates the vacuum pump from the processing chamber, and a dry gas is introduced to wind up foreign matter and trap it with an electrostatic precipitator. It is also an effective method to repeat the operations of removing foreign matter by introducing a dry gas and desorbing adhering matter by plasma excitation.

It is also effective to place the electric dust collector inside the exhaust duct 17 or in the lower vacuum chamber near the inlet of the exhaust duct 17.

It is also effective to provide a blower having a gas suction force, such as a cleaner, at the tip of the exhaust duct 17.

Next, another embodiment of the present invention will be described with reference to FIG.

In FIG. 3, when the same etching process as that described with reference to FIG. 1 is repeated, dust produced by the reaction product accumulates on the electrodes 7, the reaction processing chamber 1 and the lower vacuum chamber 6. When the accumulation of dust due to reaction products exceeds the limit, cleaning by this method is started. That is, etching is stopped, the reaction processing chamber is not opened to the atmosphere as it is, the vacuum valve 20 is closed, and dried inert gas or nitrogen is blown into the processing chamber and the lower vacuum chamber from the gas introduction pipes 40 and 41. The gas introduction pipes 40 and 41 are movably sealed between the vacuum and the atmosphere by the seal portions 44 and 45, and can be moved in the front-rear direction and can be rotated. For example, the gas introduction pipe 40 is normally located in the lower vacuum chamber 6, but when cleaning is started, it is moved to the upper etching chamber side by a movable mechanism (not shown) so that the blowout port 48 of the gas introduction pipe is just the electrode. Bring it to a position just next to the top of 7. Then, dry gas is blown out to blow off dust on and next to the electrodes. Further, if the gas inlet pipe 40 is rotated around the axial direction, the gas outlet 4
The gas blown from 8 hits the electrodes evenly,
Dust can be effectively blown away. Further, at the time of the above operation, the gas discharge pipe 42 is moved upward from the lower vacuum chamber 6 at the same time, and the gas discharge port 49 is arranged so as to come to a position corresponding to the upper side of the electrode 7. Thus, when the pressure inside the processing chamber becomes equal to or higher than the atmospheric pressure, exhaust is started, and the dust that has risen up by the introduced gas is placed on the air stream and is removed from the exhaust pipe 42 to the outside. If the exhaust pipe 42 can rotate not only in the vertical direction but also in the vertical direction, it is possible to more effectively suck and remove the rising dust. Part of the dust soared by the blowing of the gas also soars to the side of the lower vacuum chamber 6. The dust that descends to the lower side is also carried outside by being carried by the gas exhaust port 43 provided near the bottom surface of the lower vacuum chamber 6. If the suction port of the exhaust port 43 is opened in the direction parallel to the bottom surface and is made rotatable, the dust can be effectively removed. Further, the gas introduction pipe 41 is provided to blow off dust in the lower vacuum chamber, and can be moved back and forth and rotated so that the introduced dry gas uniformly hits the bottom surface and the side surface of the lower vacuum chamber. ing.

Next, another embodiment of the present invention will be described with reference to FIG.

In FIG. 4, the laser light emitting section 3 is arranged so that the laser light passes through the quartz bell jar 2 and the reaction processing chamber 1.
0 and its light receiving portion 31 are arranged. Reference numerals 32 and 33 are radio waves and a display unit. The transmittance of laser light changes depending on the degree of deposition of reaction products in the reaction chamber. Therefore, if the change in the intensity of the laser light is monitored, the degree of accumulation of reaction products in the reaction processing chamber can be known. When the amount of change exceeds a certain level, the etching process is stopped and the cleaning process is started. Since the cleaning time is determined not by the number of processed sheets but by the monitor value that knows the progress of contamination, according to the present embodiment, foreign matter does not increase abnormally and unnecessary cleaning is also performed. Since it is unnecessary, the device can be operated with high reliability and with a minimum required cleaning time.

Further, by utilizing this monitor device, the device including the vacuum processing and the cleaning processing can be completely automated without human intervention.

Although one embodiment of the present invention has been described above with respect to the etching apparatus, it can be similarly applied to the entire vacuum processing apparatus such as a film forming apparatus and an ion implantation apparatus.

[0025]

According to the present invention, foreign matter inside can be cleaned without exposing the vacuum processing chamber to the outside air containing water. Therefore, in order to improve the operation rate of the vacuum processing apparatus,
Can produce a very large effect.

Further, since it is possible to specify the time for cleaning by the monitor, it is possible to determine the cleaning process with high reliability and the minimum required frequency, and it is possible to produce the effect of improving the operation rate of the apparatus. Further, there is an effect that the vacuum processing and the cleaning processing can be automatically performed.

[Brief description of drawings]

FIG. 1 is a side sectional view of a vacuum processing apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a side sectional view of a vacuum processing apparatus according to another embodiment of the present invention.

FIG. 4 is a side sectional view of a vacuum processing apparatus according to another embodiment of the present invention.

[Explanation of symbols]

1 ... Reaction processing chamber, 2 ... Quartz bell jar, 3 ... Magnet, 4 ...
Magnetron, 5, 50 ... microwave waveguide, 6 ... lower vacuum chamber, 7 ... electrode, 8 ... wafer, 9 ... exhaust duct, 10
... vacuum pump, 11 ... etching gas supply port, 12, 2
4 ... Drying gas inlet for cleaning, 13 ... Drying gas, 14 ... Mobile electric dust collector, 16 ... Roughing vacuum pump, 17 ... Cleaning gas discharge duct, 20 ... Vacuum valve, 21 ... Base flange, 22 ... valve.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical indication H01L 21/265

Claims (9)

[Claims] 1. A vacuum processing method, characterized in that after vacuum processing, cleaning is performed by introducing a dry gas into a reaction chamber in accordance with a cleaning time and continuously exhausting the dry gas from an exhaust port side. 2. An adsorbate or a reaction product is desorbed from the surface by electrically striking the wall of the reaction chamber or the surface of a component by forming plasma for cleaning for a specific time after vacuum processing, and then stopping the plasma. By introducing a dry inert gas at atmospheric pressure level from the gas inlet of the reaction chamber and continuously exhausting the dry gas from the exhaust port side together with the suspended dust,
A vacuum processing method characterized in that cleaning is performed by repeating the above two steps. 3. A vacuum processing apparatus in which a dust collector is provided in the middle of a gas passage on the exhaust port side. 4. A vacuum processing apparatus, wherein an exhaust port for the dry gas introduced for cleaning is provided upstream of an inlet valve of a vacuum pump. 5. A vacuum having a control device for arranging a monitor capable of detecting a level of accumulation of reaction products in a reaction chamber in the device and controlling a cleaning time according to a value of the arranged monitor. Processing equipment. 6. A movable gas introducing pipe for introducing dry gas into the vacuum chamber is provided, and the gas introducing pipe is freely moved during cleaning so that the dry gas is blown in any direction in the vacuum processing chamber. A vacuum processing apparatus characterized in that it can be taken out. 7. The vacuum processing apparatus according to claim 6, wherein the gas blow-out port of the movable gas introduction pipe is movable to a position facing the electrode surface. 8. A movable gas exhaust pipe together with a movable gas intake pipe is provided in the vacuum chamber, and the outlet of the gas intake pipe and the suction port of the gas exhaust pipe are freely moved during cleaning, so that the dry gas is placed in the vacuum chamber. The vacuum processing apparatus is characterized in that the gas is discharged while the gas is blown. 9. A fan is provided on the outlet side of the movable gas discharge pipe to have a gas suction action.
The vacuum processing apparatus described.