JP2000235835A - Drive method for ion source for ion beam machining apparatus and drive method for ion beam machining apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce frequency of occurrence of breakdown due to particle and improve opening time of an apparatus by operating with stable condition of the apparatus for a long time and minimizing maintenance work such as cleaning work for the apparatus. SOLUTION: In an ion source 1 which introduces gas into a vacuum case and generates a plasma of the gas to provide electric field and extract ion in the plasma as ion beam, an ion power source is provided with an arc power source 7, an accelerating power source 8 apparatus positive electric potential to an accelerating electrode 2 for extracting the ion beam and a decelerating power source 9 applying negative electric potential for prevention of inflow of electrons. When the ion surface 1 is driven, the negative electric potential is applied to the electrode 3 after the positive potential is applied to the electrode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation method of an ion source for an ion beam processing apparatus and an operation method of an ion beam processing apparatus, and more particularly to an ion beam processing apparatus for ion beam milling or ion beam sputtering. The present invention relates to an operation method of an ion source for an ion beam processing apparatus for extracting ions in plasma generated in an ion source as an ion beam, and an operation method of the ion beam processing apparatus.

[0002]

2. Description of the Related Art In an ion beam processing apparatus, positive ions are used. When this ion beam collides with a workpiece, a positive charge is accumulated on the surface of the workpiece, so that a sufficient ion beam is continuously provided. Cannot be caused to collide with the processing location of the workpiece. For this reason, conventionally, a nutrizer for keeping the surface of the workpiece irradiated with electrons on the surface of the workpiece electrically neutral is provided.

Prior to processing a workpiece, a nut riser fills a processing chamber for accommodating the workpiece with electrons.
The ion beam is irradiated on the workpiece, and at the same time, the operation is performed so that neutralization of the workpiece surface can be started.

Conventionally, when starting an ion source, usually, an ion generator generates plasma to generate ions, while a processing chamber generates electrons by a nutrizer. For this reason, it is required to have a shielding effect of preventing electrons from flowing into the ion generation unit from the processing chamber. In order to have such a shielding effect, first, the deceleration power source of the ion source power source is turned on, a negative voltage is applied to the deceleration electrode, and then the acceleration power source is turned on to apply a positive voltage to the acceleration electrode. Is being applied.

[0005]

However, when the above-described ion source operating method is applied to an ion beam processing apparatus, particles may adhere to the electrode portion of the ion source and short-circuit between the accelerating electrode and the decelerating electrode. In some cases, the deceleration power supply that is started up first is repeatedly broken down.

Most of the causes of the breakdown of the ion source power supply are due to short-circuits at the ion source electrode due to particles at the ion source electrode. In most cases, the particles adhere to the wall surface inside the processing chamber. When a voltage is applied to these electrodes while the sputter deposits are peeled conductive materials and such particles are attached to the accelerating and decelerating electrodes of the ion power source,
A short circuit occurs between the two electrodes, a short-circuit current flows through the ion source power supply, the power supply stops due to overcurrent detection, and the operation of applying voltage again after a certain period of time is repeated. This operation is repeated until it is burned out or removed by the short-circuit current.

Normally, the acceleration power supply and the deceleration power supply of the ion source power supply have a larger capacity than the deceleration power supply. For example, the acceleration power supply has a maximum output of 1.3 kv,
3A, while the deceleration power supply has a maximum output of 500V,
0.2A or the like. This is because the acceleration power supply needs to flow the ion beam current when extracting the ion beam, but the deceleration power supply hardly needs to flow the current due to the ion beam. Are not required to have the same capacity.

In general, the overcurrent detection value of each power supply is set so as to be proportional to the rated maximum current value of each power supply. Therefore, a power supply with a smaller current capacity detects an overcurrent with a smaller overcurrent. Will work. Therefore, when particles are present in the ion source electrode portion, when a deceleration voltage is applied, a short-circuit current flows through the particles,
Due to overcurrent detection of the deceleration power supply, the power supply stops once,
After a certain period of time, the operation of applying the deceleration voltage again is repeated, and it is difficult to start up the acceleration power supply. Furthermore, when the particle size is small, when a short-circuit current flows through the particle, the particle burns out and the particle is removed from the electrode portion. However, when the particle has a certain size, the particle flows to a small-capacity deceleration power supply. Since the particles cannot be burned off by the short-circuit current, they remain at the electrode portion, and the ion source repeats the operations of overcurrent detection, trip (breakdown), and restart.

It is important for those who use these apparatuses to operate the apparatus in a stable state for a long time, to minimize maintenance work such as cleaning the apparatus, and to improve the operation time of the apparatus. For this purpose, it is important to minimize the frequency of occurrence of breakdown, to start up the apparatus early in a stable state, and to maintain a stable operation state.

In general, when the apparatus is started after the cleaning operation inside the apparatus or after the cleaning operation for the ion source electrode, breakdown of the ion power supply frequently occurs due to particles at the ion source electrode portion. By the way,
It is difficult for particles that cause breakdown to be removed from the ion source electrode portion, and it takes a long time to reach a stable operation state in which breakdown continues and there is almost no breakdown. In order to improve the situation, it is necessary to frequently clean the ion source electrode portion, and it has been difficult to improve the operation time of the apparatus.

An object of the present invention is to reduce the frequency of occurrence of breakdown, smooth the start-up of the ion source, and maintain the ion source electrode, such as cleaning work, in view of the above-mentioned problems of the prior art. It is an object of the present invention to provide an operation method of an ion source for an ion beam processing apparatus and an operation method of an ion beam processing apparatus, which improve the performance, the reliability of the apparatus, and the operation rate of the apparatus.

[0012]

According to the present invention, there is provided an ion source for introducing a gas into a vacuum vessel, converting the gas into plasma, applying an electric field, and extracting ions in the plasma as an ion beam. The power supply includes an arc power supply, an acceleration power supply that applies a positive potential to an acceleration electrode to extract an ion beam, and a deceleration power supply that applies a negative potential to a deceleration electrode to prevent inflow of electrons. When operating the ion source power supply, the negative potential is applied to the deceleration electrode after or simultaneously with the application of the positive potential to the acceleration electrode.

[0013]

FIG. 1 is a diagram showing the configuration of an ion beam processing apparatus according to this embodiment.

In FIG. 1, reference numeral 1 denotes an ion source. The ion source 1 includes an acceleration electrode 2 to which a positive potential is applied, a deceleration electrode 3 to which a negative potential is applied, an ion source chamber 4, and a heat source. And a filament 5 for emitting electrons. 6 is a filament power supply for heating the filament 5, 7 is an arc power supply for generating plasma in the ion source chamber 4, 8 is an acceleration power supply for applying an acceleration voltage to the acceleration electrode 2 to extract an ion beam, and 9 is an acceleration power supply. A deceleration power supply for applying a deceleration voltage to the deceleration electrode 3 to prevent the flow of electrons from the processing chamber 11 into the ion source chamber, a control device 10 for operating the power supplies 6, 7, 8, and 9; It is a processing room.

A processing chamber 11 has a holder 13 on which a workpiece 12 is placed, and a neutralizer 14 for generating electrons.
And a shutter 15 for preventing the workpiece 12 from being irradiated with the ion beam. Reference numeral 16 denotes a power supply for a neutralizer, and reference numeral 17 denotes a shutter driving device. The power supply 16 for the neutralizer and the shutter driving device 17 are controlled by the control device 10.

The ion source 1 is used in a state where it is attached to the processing chamber 11 to form a vacuum vessel. Further, the control device 10 controls the applied voltage, generated current or operation timing of the filament power supply 6, arc power supply 7, acceleration power supply 8, deceleration power supply 9, neutralizer power supply 16 and shutter drive device 17.

The conventional operation procedure is as follows. After a gas for plasma generation is introduced into the ion source 1 and a predetermined pressure is reached, the filament 5 is energized, and then the deceleration power supply 9 is started to apply a deceleration voltage to the deceleration electrode 3. Is applied. Thereafter, the acceleration power supply 8 is activated to apply an acceleration voltage to the acceleration electrode 2, and finally, the arc power supply 7 is applied to generate plasma and extract an ion beam. In this driving method, as explained earlier,
When particles are attached to the acceleration electrode 2 and the deceleration electrode 3 of the ion power source, when a voltage is applied to the deceleration electrode 3 in this state, the acceleration electrode 2 and the deceleration electrode 3 are short-circuited, and 9, a short-circuit current flows, an overcurrent is detected, and the deceleration power supply 9 is stopped. After a certain period of time, the operation of restarting the deceleration power supply 9 and applying a voltage to the deceleration electrode 3 is repeated.

FIG. 2 is a diagram for explaining the operation procedure of the ion source power supply according to the present invention.

As shown by the arrow, the operation procedure is as follows: a plasma generating gas is introduced into the ion source 1 and the filament 5 is energized after a predetermined pressure is reached.
And apply an accelerating voltage to the accelerating electrode 2, and then
The deceleration power supply 9 is started and a deceleration voltage is applied to the deceleration electrode 3. Finally, the procedure is to apply the arc power source 7 and extract the ion beam.

Although the basic principle and operation of the present invention have been described with reference to the time chart shown in FIG. 2, the overall preferable operation procedure of the present invention will be further described with reference to the flowchart shown in FIG. explain.

FIG. 3 is a flowchart showing the operation of the control device 10 of FIG. In FIG. 5, when the operation of the control device 10 is started, first, in step 30, the shutter 15 is inserted by the shutter driver 17 so that the workpiece 12 is not irradiated with ions or electrons from the ion source side. Next, in step 31, after the plasma generating gas is introduced into the ion source chamber 4, the filament power supply 6 is operated so that the filament 5 is energized, and the arc voltage is supplied to the arc power supply 7. And step 3
In step 2, the acceleration power supply 8 is operated to supply the acceleration voltage to the acceleration electrode 2, and then in step 33, the deceleration power supply 9 is operated to supply the deceleration voltage to the deceleration electrode 3. Further, at step 34, the neutralizer 14 is energized to the neutralizer power supply 16 to generate electrons for neutralizing the surface of the workpiece.

With the above series of operations, preparation for starting the ion source is completed. Subsequently, in step 35, the shutter driving device is operated to remove the shutter 15,
The process proceeds to the processing of the workpiece in step 36.

According to this operation procedure, an acceleration voltage is first applied from the acceleration power supply 8 having a large power supply capacity in a state where particles adhere to the portions of the acceleration electrode 2 and the deceleration electrode 3, so that acceleration is performed via the particles. Electrode 2 and deceleration electrode 3
The short circuit occurs between them, and a short-circuit current flows through the acceleration power supply 8, and the short-circuit current continues to flow through the particles on the electrodes 2 and 3 until the output of the acceleration power supply 8 stops due to overcurrent detection. Since the rated maximum current value of the acceleration power supply 8 is about several amperes, the acceleration power supply 8 does not trip until the short circuit current reaches an overcurrent set value slightly larger than the rated maximum current value, for example, 120% of the rated maximum current value.

As described above, according to the operation method of the ion source power supply of this embodiment, the short-circuit current is large because the power supply capacity of the acceleration power supply 8 is large, and the time required for detecting the overcurrent is accordingly long. It can be longer than the power supply operation method. As a result, a large short-circuit current can be passed for a longer time to the particles causing the short-circuit of the electrodes 2 and 3 than in the conventional operation method. The heat generated by the application of the short-circuit current causes the particles to be melted or removed at a high temperature, or evaporates in a vacuum, and the short-circuit state of the electrodes 2 and 3 is efficiently eliminated.

Further, according to the present embodiment, a larger short-circuit current can be flowed for a longer time by the acceleration power supply 8 having a large power supply capacity, so that particles having the same size can be removed in a shorter time. Can, and
Particles of a larger size, which could not be removed because the current was small in the past, can also be removed. As a result, even if a breakdown occurs, the breakdown can be eliminated in a short time, and the frequency of maintenance work such as cleaning of the ion source electrode for eliminating the breakdown can be reduced.

In this embodiment, after the acceleration power supply 8 is started and the acceleration voltage is applied to the acceleration electrode 2, the deceleration power supply 9 is started and the deceleration voltage is applied to the deceleration electrode 3. It is also possible to simultaneously start up the power supply 9 and apply an acceleration voltage and a deceleration voltage to the acceleration electrode 2 and the deceleration electrode 3, respectively. In this case, the acceleration electrode 2 and the deceleration electrode 3
During this time, the added voltage of the acceleration power supply 8 and the deceleration power supply 9 is applied, so that the short-circuit current can be further increased, and the particles can be removed in a short time.

[0027]

According to the present invention, there is a problem in an ion beam processing apparatus or the like by controlling the operation of applying the voltage of the ion source power supply so as to apply the deceleration voltage after or simultaneously with the application of the acceleration voltage. Reduces the frequency of breakdowns that occur in the ion source, especially the breakdown caused by particles generated in the electrode section unique to the ion source, smoothes the startup of the ion source, and cleans the ion source electrode section This makes it possible to realize stable operation of the apparatus, such as improvement of maintainability of the apparatus, improvement of apparatus reliability, and improvement of apparatus operation rate.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an ion beam processing apparatus according to the present invention.

FIG. 2 is a time chart showing an operation procedure of the present invention.

FIG. 3 is a flowchart showing an operation procedure of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ion source, 2 ... Acceleration electrode, 3 ... Deceleration electrode, 4 ... Ion source chamber (anode), 5 ... Filament, 6 ... Filament power supply, 7 ... Arc power supply, 8 ... Acceleration power supply, 9 ... Deceleration power supply, 10 ... Control device, 11: processing chamber, 12: workpiece,
13: Holder, 14: Neutralizer, 15: Shutter, 16: Power supply for neutralizer, 17: Shutter driving device.

Claims (7)

[Claims] 1. An operation method of an ion source for an ion beam processing apparatus, comprising: an arc power supply; an acceleration power supply for applying a positive voltage to an acceleration electrode to extract an ion beam; A deceleration power supply that applies a negative voltage to the deceleration electrode to prevent the inflow of electrons into the ion source.The gas is introduced into the ion source, the gas is turned into plasma, an electric field is applied, and ions in the plasma are ionized. An ion source for an ion beam processing apparatus, wherein the ion source is configured to extract as a beam, and the deceleration power source applies a negative voltage to the deceleration electrode after the acceleration power source applies a positive voltage to the acceleration electrode. Driving method. 2. A method for operating an ion source for an ion beam processing apparatus, comprising: an arc power supply; an acceleration power supply for applying a positive voltage to an acceleration electrode to extract an ion beam; A deceleration power supply that applies a negative voltage to the deceleration electrode to prevent the inflow of electrons into the ion source.The gas is introduced into the ion source, the gas is turned into plasma, an electric field is applied, and ions in the plasma are ionized. An ion source for an ion beam processing apparatus, which is configured to extract as a beam, wherein the acceleration power supply applies a positive voltage to the acceleration electrode and the deceleration power supply applies a negative voltage to the deceleration electrode at the same time. Driving method. 3. An operation method of an ion source for an ion beam processing apparatus, wherein the ion source includes an arc power supply, an acceleration power supply for applying a positive voltage to an acceleration electrode for extracting an ion beam, and an ion source. A deceleration power supply that applies a negative voltage to the deceleration electrode to prevent the inflow of electrons into the ion source.The gas is introduced into the ion source, the gas is turned into plasma, an electric field is applied, and ions in the plasma are ionized. A first step in which, after the acceleration power supply applies a positive voltage to the acceleration electrode, the deceleration power supply applies a negative voltage to the deceleration electrode; and A second step in which the deceleration power supply applies a negative voltage to the deceleration electrode at the same time as applying a positive voltage to the acceleration electrode, wherein the first step and the second step The method of operating an ion beam processing system for an ion source which is adapted to run selectively towards. 4. An operation method of an ion beam processing apparatus, wherein the ion beam processing apparatus has an ion source and a processing unit, and the ion source has a positive power supply to an arc power supply and an accelerating electrode for extracting an ion beam. And a deceleration power supply for applying a negative voltage to the deceleration electrode to prevent the inflow of electrons into the ion source. A gas is introduced into the ion source, and the gas is turned into plasma. The processing unit is configured to extract ions in the plasma as an ion beam by applying an electric field to the processing unit. And a neutralizer for generating electrons for electrically neutralizing the surface of the workpiece, wherein the acceleration power supply applies a positive voltage to the acceleration electrode.
A second step in which the deceleration power supply applies a negative voltage to the deceleration electrode after the execution of the first step, and a third step of activating the nutrizer after performing the second step. An operation method of an ion beam processing apparatus having steps. 5. The method of operating an ion beam processing apparatus according to claim 4, further comprising the step of inserting said shirt to prevent irradiation of said workpiece with ions before executing said first step. 6. The method of operating an ion beam processing apparatus according to claim 5, further comprising the step of removing said shirt after the execution of said third step. 7. The method of operating an ion beam processing apparatus according to claim 4, further comprising the step of executing the work of processing the workpiece after performing the third step.