KR102478688B1 - Method for cleaning ion beam irradiation device - Google Patents

Abstract

(Project) To propose an effective and efficient cleaning method capable of reducing and stabilizing particles in a beam line at an early stage.
(Solution Means) A cleaning method in an ion beam irradiation apparatus for performing an ion beam irradiation treatment on an object to be treated using a halogen-containing gas, wherein an ion beam derived from a hydrogen-containing gas is irradiated to the object to be irradiated, and then an ion beam derived from an inert gas is irradiated. investigate things

Description

Cleaning method of ion beam irradiation device {METHOD FOR CLEANING ION BEAM IRRADIATION DEVICE}

It relates to a method of cleaning a beam line of an ion beam irradiation device.

In the ion beam irradiation apparatus, deposits are formed over time on members such as electrodes, vacuum containers, and slits constituting the beam line. At the time of removing this deposit, physical sputtering using an ion beam is performed.

For example, in Patent Document 1, deposits on the analysis slit are removed in a wide range by adjusting the applied voltage to a pair of deflection electrodes and irradiating the analysis slit with an ion beam based on argon gas.

Special 2016-48665

There are various types of gas used for cleaning, and even if cleaning is performed using argon gas as in Patent Document 1, sufficient cleaning is not always possible. In addition, if the ion beam irradiation process is performed on the object to be treated in a state in which the amount of particles in the beam line generated through cleaning (such as debris scattered in the beam line) is large, processing failure may occur. There is a problem that says it can't be done.

Here, the present invention proposes an effective and efficient cleaning method capable of reducing and stabilizing particles in a beam line at an early stage.

The cleaning method of the present invention,

A cleaning method in an ion beam irradiation apparatus for performing an ion beam irradiation treatment on an object to be treated using a halogen-containing gas, comprising:

After irradiating the irradiated object with an ion beam derived from a hydrogen-containing gas,

An ion beam derived from an inert gas is irradiated to an object to be irradiated.

According to the above method, the deposits derived from the halogen element can be removed with the hydrogen component, and the remaining deposits can be removed by beam sputtering using an inert gas. In addition, since cleaning with hydrogen-containing gas, which reduces particles in the beam line and requires a relatively long time to stabilize, is first performed, it becomes possible to start the ion beam irradiation device early and perform the ion beam irradiation process.

A portion on the beam line to which the ion beam is irradiated is shielded with a member containing carbon as a countermeasure against metal contamination of the object to be processed.

When cleaning using an ion beam is performed, this carbon-containing member is sputtered, and the carbon component floats in the beam line, which may cause particles to delay the start of the ion beam irradiation process.

In the case of removing the above-mentioned carbon-derived particles, it is preferable to use the following structure.

A member containing carbon is used for the irradiated object,

After irradiating the irradiated object with the ion beam derived from the inert gas,

Additionally, an ion beam derived from a halogen-containing gas or an oxygen-containing gas is irradiated to the irradiated object.

According to the above method, carbon-derived particles react with halogen elements and oxygen radicals to vaporize, so that it is easy to exclude them from the beam line.

In order to avoid miniaturization of the device dimensions and cumbersome gas management, it is preferable to use at least one of the gases used for cleaning with the gas used for the ion beam irradiation treatment.

In order to reduce particles floating in the beam line after cleaning and stabilize it at an early stage, it is preferable to transfer the dummy substrate to the ion beam irradiation position during substrate processing after irradiating the target with an ion beam derived from the inert gas. In addition, after irradiating the irradiated object with an ion beam derived from the halogen-containing gas or the oxygen-containing gas, it is preferable to transport the dummy substrate to the ion beam irradiation position during substrate processing.

Since particles adhere to the dummy substrate by transporting the dummy substrate to the ion beam irradiation position during substrate processing, it is possible to reduce and stabilize particles in the beam line at an early stage by collecting them.

In terms of reducing the cleaning time, the following configuration may be used.

At least one of the hydrogen-containing gas and the inert gas is a mixed gas composed of a plurality of gases having different masses, and the irradiated object is irradiated with a scanned ion beam.

Deposits derived from halogen elements can be removed with a hydrogen component, and the remaining deposits can be removed by beam sputtering with an inert gas. Further, since cleaning with hydrogen-containing gas, which reduces particles in the beam line and requires a relatively long time to stabilize, is performed first, it becomes possible to start the ion beam irradiation device early and perform the ion beam irradiation process.

1 is a plan view showing an example of the configuration of an ion beam irradiation device.
Fig. 2 is a plan view showing a configuration example related to ion beam scanning.
3 is a flowchart illustrating an embodiment related to cleaning.
4 is a flowchart illustrating another embodiment related to cleaning.
5 is a flowchart illustrating another embodiment related to cleaning.

1 is a schematic plan view showing the entirety of an ion beam irradiation device (IM). The ion beam irradiation device IM shown in the drawing assumes a well-known ion implantation device. Hereinafter, the configuration of this device will be briefly described.

From the plasma generated in the plasma production chamber 1, the ion beam IB is taken out through a drawing electrode system 2 composed of a plurality of electrodes. The extracted ion beam IB includes various ion species. Mass analysis of desired ion species is performed through the mass spectrometry electromagnet 4 and the analysis slit 5, and the ion beam IB is transported into the processing chamber 6.

In the processing chamber 6, the object to be processed 7 (for example, a silicon wafer or a glass substrate) is mechanically reciprocally transported in the direction indicated by an arrow. The size of the ion beam IB transported in the processing chamber 6 in the direction of the front and back of the paper is larger than the size of the object 7 in that direction, and the object 7 is moved in the direction of the arrow shown in the drawing (Fig. The entire surface of the object 7 is irradiated with ion beams by reciprocating scanning in the up-and-down direction).

The beam line of the ion beam IB is covered with a vacuum container 3, and while the processing target 7 is being processed, the inside of the container is maintained in a vacuum.

During the ion beam irradiation treatment of the object to be processed, a process gas P which is a halogen-containing gas (eg, BF ₃ , vaporized AlI ₃ or AlF ₃ ) is supplied to the plasma chamber 1 . During cleaning in the beam line, a hydrogen-containing gas (C1) or an inert gas (C2) is selectively supplied to the plasma chamber (1).

The cleaning of the present invention is performed by irradiating an ion beam to a member or site (irradiated object) to be cleaned. If the target member is large and cleaning needs to be performed over a wide area, beam scanning as shown in FIG. 2 may be used.

When a halogen-containing process gas is used, the halogen component reacts with members disposed in the beam line to generate halides. These halides are deposited on members over time, and cause insulation of members and abnormal discharge between members.

In order to remove this, beam sputtering by an ion beam is performed without breaking the vacuum in the vacuum vessel 3.

In Fig. 2(A), the ion beam IB is scanned by changing the strength of the magnetic field B generated from the mass spectrometer electromagnet 4 toward the inside of the page with time. By this scanning, it becomes possible to irradiate the ion beam IB over a wide area by changing the trajectory of the ion beam as indicated by arrows.

In addition, in the example of FIG. 2(A), the carbon liner S is arrange|positioned along the container wall surface in order to prevent consumption of the vacuum container 3.

In FIG. 2(B), the middle electrode constituting the lead electrode system 2 is composed of a set of upper and lower electrodes, and a high frequency power supply is connected to each electrode. Since the waveforms of the high-frequency voltages output from each power supply have a phase difference of 180 degrees, it becomes possible to irradiate the ion beam IB over a wide area to the wall surface of the vacuum container by scanning the ion beam IB in a large up-and-down direction in the drawing.

In some cases, in order to avoid metal contamination, the lead-out electrode system 2 is made of carbon electrodes.

The configuration described above refers to a configuration in which the ion beam IB is scanned using the mass spectrometer electromagnet 4 or the drawing electrode system 2, but depending on the configuration of the ion beam irradiation device, other optical elements may be used to scan the ion beam. It is also possible to make the injection of

Further, in the present invention, temporal scanning of the ion beam is not essential, and any configuration capable of deflecting the ion beam at a predetermined angle so that the ion beam is irradiated to a predetermined portion is sufficient.

In the cleaning using the ion beam described above, as a result of extensive research by the inventors, it has been found that the amount of time required for particles in the beam line to decrease and stabilize varies depending on the type of gas used.

According to the experiment of the inventors, comparing the case of using hydrogen gas and the case of using argon gas, the cleaning using hydrogen gas reduces the number of particles and requires about twice as much time to stabilize. I found out that the time to do it is getting longer.

Based on this, in the present invention, the beam line is cleaned in the order shown in FIG. 3 . Specifically, the member (electrode constituting the drawing electrode system) of the present invention disposed in the beam line using a hydrogen-containing gas (eg, hydrogen gas, PH ₃ , etc., or a mixture thereof) at the beginning of cleaning , a member such as a liner in a wall surface of a vacuum container or a mass spectrometer electromagnet) is irradiated with an ion beam (S1). Next, the cleaning gas is changed to an inert gas composed of argon, xenon, or a mixture thereof, and the same member or portion is irradiated with an ion beam (S2).

In the present invention, plasma is generated from the hydrogen-containing gas described above, and an ion beam extracted from the plasma is called an ion beam derived from the hydrogen-containing gas, and the same expression is used for other gas types described later.

By performing the cleaning in this way, since the halogen-derived deposits are removed with the hydrogen component and the remaining deposits can be removed by beam sputtering using an inert gas, effective cleaning can be realized compared to the case of using only argon gas.

In addition, since the cleaning with hydrogen-containing gas, which reduces the number of particles in the beam line and takes a relatively long time to stabilize, is performed first, the ion beam irradiation device is started earlier than when the order of cleaning is reversed, It becomes possible to perform ion beam irradiation processing.

A site on the beam line to which the ion beam is irradiated is shielded with a member containing carbon as a countermeasure against metal contamination of the object to be processed.

In addition, the electrode constituting the lead-out electrode system 2 is also made of carbon.

When cleaning using an ion beam is performed, such a carbon-containing member is sputtered, and the carbon component floats in the beam line, which may cause particles to delay the start of the ion beam irradiation process.

Therefore, as shown in the flowchart shown in Fig. 4, after performing beam cleaning using an inert gas, the cleaning gas is switched to a halogen-containing gas or an oxygen-containing gas, and beam cleaning using these gases is performed (S3).

By performing such beam cleaning, halogen radicals and oxygen radicals contained in the ion beam react with carbon-derived particles to vaporize the particles, making it easy to exclude carbon-derived particles from the beam line.

In addition, in FIG. 4 and the flow chart of FIG. 5 to be described later, the processing using the same reference numerals as those in FIG. 3 is the same as the content described using the flow chart in FIG. 3, and redundant descriptions are omitted here.

In addition, in order to reduce and stabilize particles floating on the beam line after cleaning, as shown in the flowchart shown in FIG. 5, after cleaning using an ion beam, the dummy substrate is transported to the ion beam irradiation position during substrate processing ( S4) may be performed.

Since particles adhere to the dummy substrate by transporting the dummy substrate to the ion beam irradiation position during substrate processing, it is possible to reduce and stabilize particles in the beam line at an early stage by collecting them.

Note that the dummy substrate referred to here refers to a substrate that has not been subjected to ion beam irradiation.

In the flowcharts of FIGS. 3 to 5 described above, a configuration using a gas other than a hydrogen-containing gas or an inert gas is mentioned, but in this case, in the configuration example of the device shown in FIG. 1, supplying to the plasma generation chamber 1 The number of gas supply sources may be increased.

However, if the number of gas supply sources is increased, there is a risk that the size of the device becomes large or that gas management becomes complicated.

Considering this point, it is preferable to make the halogen-containing gas or the oxygen-containing gas compatible with what is used as a process gas rather than forming a special gas as a cleaning gas.

In the ion beam irradiation treatment, when an assist gas for assisting plasma generation or a gas for suppressing discharge is used in addition to the process gas, these gases may also be used as the cleaning gas.

The configuration of the ion beam irradiation device described in the above embodiment is an example, and components not disclosed in 1 may be added to the beam line as well. For example, various components such as a beam optical element for adjusting the beam current density distribution, an acceleration/deceleration tube for adjusting the energy of the ion beam, and an energy filter for removing unnecessary energy components may be added.

In addition, the ion beam irradiation device assumed in the present invention is not limited to an ion implantation device, and may be a surface modification device using an ion beam.

The cleaning method described in the above embodiment may be performed by an operator of the apparatus manually changing the gas type as appropriate, but may be automated.

In the case of automation, a program for performing cleaning is installed in a control device that controls beam irradiation or gas conversion of the ion beam irradiation device.

Further, a series of cleanings shown in the flow charts of FIGS. 3 to 5 may be repeatedly performed a plurality of times.

Further, when a series of cleanings are performed a plurality of times, the amount of cleaning gas or the time required for cleaning may be changed each time.

In the above embodiment, although the effect of using a halogen-containing gas as the process gas has been described, the ion beam irradiation device is not intended to be only a dedicated device for performing a process using only the halogen-containing gas.

That is, an ion beam irradiation apparatus for performing an ion beam irradiation treatment on an object to be treated using a halogen-containing gas as referred to in the present invention has a process gas in addition to the halogen-containing gas, and uses various gases to perform ion beam irradiation corresponding to a plurality of processes. Devices are also assumed.

Further, in the above embodiment, by combining the hydrogen-containing gas or the inert gas with a mixture of a plurality of types of gases having different masses and the scanning of the ion beam, a difference in scanning amount occurs depending on the difference in mass, so that the ion beam Since the range to be irradiated is widened, the cleaning time can be shortened.

In addition to the above, it goes without saying that various improvements and changes may be made within a range not departing from the gist of the present invention.

IM ion beam irradiation device
IB ion beam
1 Plasma generation room
2 draw electrode system
3 vacuum vessel
4 mass spectrometer electromagnet
5 analysis slits
6 processing room
7 Objects to be processed
P process gas
C1 hydrogen containing cleaning gas
C2 noble gas

Claims (6)

In an ion implantation apparatus for performing an ion beam irradiation process on a target object using a halogen-containing gas, a hydrogen-containing gas as a cleaning gas and an inert gas are selectively supplied to a plasma chamber, and an ion beam extracted from the plasma chamber forms a beam line In the method of cleaning,
After irradiating the irradiated object with the ion beam derived from the hydrogen-containing gas,
Irradiating the irradiated object with an ion beam derived from the inert gas;
The hydrogen-containing gas is hydrogen gas, a gas of a compound containing hydrogen as one of the constituent elements, or a mixed gas of the hydrogen gas and a gas of the compound. The method of claim 1, wherein a carbon-containing member is used for the irradiated object,
After irradiating the irradiated object with the ion beam derived from the inert gas,
Further, a cleaning method in which an ion beam derived from a halogen-containing gas or an oxygen-containing gas is irradiated to the object to be irradiated. The cleaning method according to claim 1 or 2, wherein at least one of the gases used for cleaning is used in combination with a gas used in the ion beam irradiation treatment. The cleaning method according to claim 1, wherein after irradiating the object with the ion beam derived from the inert gas, the dummy substrate is transported to an ion beam irradiation position for substrate processing. The cleaning method according to claim 2, wherein the dummy substrate is transported to an ion beam irradiation position during substrate processing after irradiating the irradiated object with an ion beam derived from the halogen-containing gas or the oxygen-containing gas. The cleaning method according to claim 1 or 2, wherein at least one of the hydrogen-containing gas and the inert gas is a mixed gas composed of a plurality of gases having different masses, and the irradiated object is irradiated with a scanned ion beam.

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