JP3355869B2 - Ion source control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion source control apparatus suitable for ion beam pulse irradiation.

[0002]

2. Description of the Related Art Conventionally, thin film manufacturing apparatuses such as an ion beam sputtering (IBS) apparatus and an ion vapor deposition (IVD) apparatus and an ion irradiation apparatus as a surface reforming apparatus use an ion source to control a thin film. In some cases, the extracted ion beam is pulse-irradiated on a substrate or the like.

Conventionally, this pulse irradiation is performed by intermittently blocking an ion beam by a shutter mechanism and mechanically turning the ion beam on and off.

On the other hand, in a conventional apparatus for continuously irradiating an ion beam onto a substrate, the ion beam is automatically operated based on feedback control of an acceleration current, an arc current (discharge current), a target current, and the like. Is controlled to be constant.

[0005]

When the pulse irradiation of the ion beam is performed by a mechanical method as in the prior art, there is a problem that a complicated and expensive mechanical shutter mechanism is required.

In the case of this conventional control, the ion source is operated continuously, and the ion beam is continuously generated even during the off period when the ion beam is not required. With the most common configuration for obtaining electrons using a (hot cathode), there is a problem that the life of the filament cannot be extended.

The present invention is realized by a method in which an ion source is pulse-operated, and pulse irradiation of an ion beam is electrically turned on and off, and furthermore, a combination of electric on / off of the ion beam and feedback control is combined. It is an object of the present invention to control an ion beam and to suppress a so-called excessive amount of feedback control during the control, thereby achieving remarkable improvement in control.

[0008]

To achieve the above object, the present invention provides an ion source control apparatus according to the present invention .
In the case, use of thermionic emission of the filament or microwave
Generates electrons and generates plasma by DC discharge
Then, an ion beam is extracted from the plasma to illuminate a substrate or the like.
A power supply unit provided with various power supplies for the ion source to be irradiated;
Automatically controls the output of all or some of the power supplies
Turn the ion source on and off to pulse the ion source
Power on / off means for pulsing and feedback
Form a feedback control loop to feedback the ion beam.
Feedback control means for controlling the
A machine that opens and closes the feedback control loop in conjunction with it
The whole or part of the power supply by the automatic control.
When the power supply output turns on, the power supply of the power supply
Time until the ion beam reaches steady state
The feedback control loop from open to closed
Loop opening / closing means for controlling the operation .

In the case of claim 2, the power on / off operation is performed.
The output of the arc power supply for generating DC discharge in the power supply section
ON / OFF by automatic control and pulse operation of ion source
And the loop control means completes the rise of the arc power supply.
Of time until the ion beam reaches steady state
Then, turn on the filament power supply or microwave power supply in the power supply section.
Control feedback loop from open to closed
It was made.

[0010]

According to the ion source control device of the present invention, the output of all or a part of the power source of the ion source provided in the power supply unit is controlled by a timer by power on / off means. on the automatic control of the sequence control, etc., it is turned off, the on, are ion source pulse operation the ion beam by off is pulse of, without on the beam, the pulse irradiation based on off using the shutter mechanism, etc. It is performed by electrical control.

Further, the feedback control means, the ion source is feedback controlled operation simultaneously being pulsed operation, the pulsed ion beam is stabilized to a certain amount.

In addition, the feedback control is turned on and off in conjunction with the on / off operation of the ion beam by the loop opening / closing means. When the ion beam is turned on, the power supply of the power supply section is completed and the ion beam is in a steady state. When the feedback control is turned on after shifting to the above, the transient overrun of the feedback control when the ion beam is turned on is suppressed, the overshoot of the beam current is suppressed, and the control is stabilized. Also,
In the case of claim 2, for generating a DC discharge for generating plasma.
Turns the output of the arc power supply on and off to generate plasma
The ion beam is pulsed,
The start of the arc power supply is completed by the loop opening / closing means.
After the ion beam reaches steady state,
Power supply or microwave power supply is feedback controlled.
The effect of claim 1 is obtained by focusing on the arc power supply of the power supply unit.
Can be

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment will be described with reference to FIGS. FIG. 1 shows an ion irradiation apparatus of a bucket type ion source configuration using a filament for a cathode, 1 is a bucket type ion source, 2 is a casing of the ion source 1, 3 is a casing 2
Is a discharge chamber formed by the internal space of the housing 2, 5 is a cathode filament provided in the discharge chamber 4, and both ends are led out through the cover plate 3 to the outside. ing. Reference numeral 6 denotes a gas inlet attached to the cover plate 3.

Numeral 7 denotes a magnetic field generating means provided on the outer periphery of the housing 2, which is made of a permanent magnet or an electromagnet and generates a cusp magnetic field.

Reference numeral 8 denotes an ion beam extraction electrode of the ion source 1 provided so as to close the left opening of the housing 2. The acceleration electrode 9 and the deceleration electrode 1 are arranged in order from the right side near the filament 5.
0, a ground electrode 11, which is grounded.

Reference numeral 12 denotes a casing that forms the irradiation chamber 13 at the subsequent stage of the ion source 1, and 14 denotes an insulator interposed between the right end opening of the casing 12 and the ion source 1. Reference numeral 15 denotes an irradiation target substrate provided in the irradiation chamber 13, which is irradiated with the ion beam 16 extracted from the extraction electrode 8.

Reference numeral 17 denotes a power supply unit of the ion source 1, and reference numeral 18 denotes a filament power supply serving as a cathode power supply provided in the power supply unit 17. Both ends of the filament 5 are connected to the positive and negative electrodes. Reference numeral 19 denotes an arc (discharge) power supply having an anode connected to the housing 2.

Reference numeral 20 denotes an accelerating power source provided between the arc power source 19 and the earth. The anode is connected to the accelerating electrode 9 and the filament power source 18 and the cathode of the arc power source 19 via an ammeter 21. Have been. Reference numeral 22 denotes a deceleration power source whose cathode is connected to the deceleration electrode 10, and the anode is grounded.

Reference numeral 24 denotes a timing control unit having a timer circuit 23, which forms a power on / off means.
A loop opening / closing means for opening / closing a feedback control loop described later is formed. Reference numeral 25 denotes a feedback control unit which forms feedback control means, and calculates a difference between an analog or digital acceleration current measured value of the ammeter 21 and an analog or digital acceleration current set value of the setting terminal 26 by an internal PI.
The signal is processed by the D controller 27 to form a feedback control signal for automatic ion beam control, and the output of the filament power supply 18 is controlled by this signal.

The housings 2, 12 and the like are formed of a non-magnetic metal material. The discharge chamber 4 and the irradiation chamber 13 are evacuated by a vacuum pump (not shown). Then, the filament 5 is energized and heated by the filament power supply 18, and electrons are generated by thermionic emission of the filament 5.

At this time, a rare gas or the like is introduced into the discharge chamber 4 from the gas inlet 6, the power is turned on by power on / off control (automatic control) by a timer operation of the timing control unit 24, and the arc power supply 19 is set. When a voltage output is generated, a DC discharge is generated, the introduced gas is ionized, and a plasma 28 is generated.

The plasma 28 is efficiently confined in the discharge chamber 4 by the cusp magnetic field generated by the magnetic field generating means 7. Further, the ion beam 16 is extracted from the plasma 28 by the action of the extraction electrode 8,
Is irradiated on the substrate 15.

Next, in this embodiment, the arc power supply 19 of the power supply section 17 is turned on and off to perform a pulse operation, and the ion beam is irradiated with a pulse. That is, the timing control unit 24
The arc power supply 19 shown in FIG.
, The ON period Ton and the OFF period Toff are set, and the timer circuit 24 alternately measures both the periods Ton and Toff.

Further, the timing control unit 24 controls the arc power supply 19 to a specified output by an ON control signal during the ON period Ton, and changes the output of the arc power supply 19 to OV by the OFF control signal during the OFF period Toff to turn off.

When the arc power supply 19 is turned off, the plasma 28 disappears, the ion beam 16 is turned off, and the ion source 1 is pulsed by turning on and off the output of the arc power supply 19.

By this pulse operation, the ion beam 16
Is electrically turned on and off without using a mechanical shutter mechanism or the like, and is irradiated with a beam.

Further, in this embodiment, the ion beam 16
Since the feedback control operation is also performed utilizing the fact that the current (ion beam current) is proportional to the acceleration current, the acceleration current based on the acceleration power supply 20 is detected by the ammeter 21 as the ion beam current.

The ammeter 21 smoothes, for example, by integrating, for example, a detected value every moment, and outputs an averaged measured value in order to prevent measurement fluctuation due to pulse operation.

Then, the measured value of the acceleration current of the ammeter 21 is supplied to the feedback control unit 25, and the feedback control processing of the so-called PID control of the control unit 25 performs
A feedback control signal is generated which pulls the measured value into the acceleration current set value at the setting terminal 26.

Further, the output of the filament power supply 18 is controlled by the feedback control signal, the power supply of the filament 5 is adjusted, and the ion beam current is controlled.

That is, a feedback control loop of the power supply unit 17 is formed by the filament power supply 18, the filament 5, the ammeter 21 and the feedback control unit 25, and the feedback control operation based on this control loop causes the ion beam current to reach the set value. It is controlled to a constant current based on the current.

When the feedback control operation and the pulse operation are performed at the same time, when the pulse operation shifts from the off-period Toff to the on-period Ton, the acceleration current becomes 0 in accordance with a rise in the output of the arc power supply 19. The output of the filament power supply 18 becomes excessive based on the control of the so-called overshoot amount of the feedback control signal during a transition period from the increase to the steady-state value. Become.

Since such overshoot of the ion beam occurs repeatedly, the ion beam 16
Becomes unstable, and good ion irradiation cannot be performed.

Therefore, in this embodiment, the arc power supply 19 is turned on and off by the loop opening / closing means of the timing control section 24.
A control signal for closing and opening the feedback control loop is supplied to the PID controller 27 in conjunction with the OFF timer control,
The feedback control loop is opened during the off-period Toff, and at the time of transition from the off-period Toff to the on-period Ton, the feedback control loop is closed with a delay of a set delay time t (sec).

The delay time t is set to a period until the rising of the arc power supply 19 is completed (the ion beam current is stabilized). Based on this setting, even if the arc power supply 19 is turned on, the PID controller 27 is turned on. As shown in FIG. 2 (c), the PID control is turned off until the rise of the arc power supply 19 is completed, and the feedback control loop is kept open.
The control of the controller 27 is turned on, and the feedback control loop is closed.

Therefore, the feedback control is performed only during the on-period Ton, and its start timing is after the completion of the rise of the arc power supply 19, that is, after the acceleration current reaches a steady value. Does not become excessive, and the overshoot of the ion beam current is suppressed. FIG. 2B is a waveform diagram of the arc voltage.

[0037] Therefore, by operating a combination of a pulse operation and the feedback controlling operation is stabilized to a constant overshoot, etc. without while being ion beam 16 Gapa <br/> Le gasification, very good pulse of the ion beam Irradiation can be performed.

In the above embodiment, only the output of the arc power supply 19 of the power supply unit 17 is turned on and off to turn on the ion beam 1.
6 has been pulse of, all power 18,1 of the power supply unit 17
9, 21 or 23 or the output of some power supplies such as the acceleration power supply 20 and the deceleration power supply 22 are turned on and off,
The may be pulse of.

In the above embodiment, the feedback control operation is performed based on the acceleration current. However, as in the conventional automatic operation control, the arc current, the arc current,
The feedback control operation may be performed based on the target current or the like.

[0040] Then, IBS device, Ru course Dare can be applied to a variety of thin-film deposition apparatus and the various surface modification device, such as IVD device.

When the present invention is applied to an apparatus for generating a plasma 28 using microwaves instead of the filament 5, a cathode power supply (microwave power supply) is provided instead of the filament power supply 18, so that this power supply is controlled by feedback. do it.

The configurations of the power supply unit 17 and the control units 24 and 25 are not limited to those in the embodiment. For example, both the control units 24 and 25 may be formed by one computer device.

Sequence control or the like may be performed as automatic control of the timing control unit 24. Further, a feedback control unit 25 is provided with a controller having a transfer function type different from that of the PID controller 27, and feedback control different from that of the embodiment is performed. It goes without saying that the present invention can be applied to the case where

[0044]

Since the present invention is configured as described above, the following effects can be obtained. First, billing
In the case of item 1, the output of all or a part of the power source of the ion source provided in the power supply unit is automatically turned on and off by the power on / off means. Is turned on and off without using a shutter mechanism, etc., to pulse the ion beam .
Pulse operation of the ion source with a simple and inexpensive configuration.
Can be realized.

At this time, all or a part of the power supply
Reduces power consumption by performing on / off pulse operation
As well as a filament on the cathode
And emit electrons by thermionic emission
Is the conduction time of the filaments short to also like to achieve its long life.

[0046] Further, the feedback control operation by the feedback control means, pulsed ion beam is regulated to a fixed amount, moreover, the loop closing means, the ion beam on, Fi of the power supply unit in conjunction with the off < br /> readback control is turned on, turned off, in particular, when the ion beam is turned on, the ion beam is feedback control is turned on after reaching a steady state rise of the power supply unit is completed, the feedback control transient specific overshoot is suppressed, Ru been attempted stabilization control is suppressed overshoot of the ion beam current. Therefore, Ionbee
The pulse can be controlled stably and stably.
At the time, since the ion beam current becomes constant, for example,
Stable when applied to ion beam sputter cylinder
To achieve a uniform film formation rate.
Various thin-film manufacturing equipment that pulse ion beam
It has a remarkable effect when applied to an apparatus for improving the quality of a membrane. Ma
In the case of claim 2, a direct current discharge generating plasma is generated.
Turns the output of the raw arc power supply on and off to generate plasma
The ion beam is pulsed
In addition, the startup of the arc power supply
After the ion beam has reached the steady state
The filament or microwave power supply is feedback controlled
2. The effect of claim 1 focusing on the arc power supply of the power supply unit.
Can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration of an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ion source 16 Ion beam 18 Filament power supply 19 Arc power supply 20 Acceleration power supply 22 Deceleration power supply 23 Timing control unit 24 Timer circuit 25 Feedback control unit

Continuation of the front page (56) References JP-A-6-208842 (JP, A) JP-A-5-314944 (JP, A) JP-A-6-150861 (JP, A) , U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 37/30-37/317

Claims (2)

(57) [Claims] 1. Thermionic emission of a filament or micro
Generates electrons by using waves and plasma by DC discharge
And an ion beam is extracted from the plasma to produce a substrate.
A power supply unit provided with various power supplies of an ion source for irradiating the ion source and the like; and turning on and off the output of all or a part of the power supply of the power supply unit by automatic control to perform a pulse operation of the ion source.
Power on / off means for pulsing the on-beam, and a feedback control loop formed in the power supply section,
Feedback control for feedback control of the beam
Means and the feedback control loop in conjunction with the automatic control
Has the function of opening and closing the
Before the output of all or part of the power supply is turned on
When the power supply of the power supply section has completed the rise, the ion beam is
After the time to reach steady state elapses,
Open the loop to control the feedback control loop from open to closed
An ion source control device comprising: closing means . 2. The method according to claim 1, further comprising the step of:
The output of the arc power supply for generating discharge is turned on by automatic control.
Off and pulse operation of the ion source.
When the start of the arc power supply is completed, the ion beam is
After the elapse of the time to reach the steady state, the power supply
Feedback control of filament power supply or microwave power supply
2. The ion source control device according to claim 1 , wherein the control loop is controlled from open to closed .