JPH0967670A - Ion beam sputtering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to form films of a prescribed film thickness regardless of the presence or absence of the discharge of the drawing-out electrodes of an ion source by determining the time for prolonging film formation from the setting of the off time to the electrodes at every detection of the discharge and the number of detection times of the discharge and prolonging and correcting the running time of the ion source. SOLUTION: The generation of the discharge between the electrodes as the drawing-out electrodes 19 of an ion beam 5 consisting of the acceleration electrode 16, deceleration electrode 17 and grounding electrode 18 is detected by a discharge detection 23. The contact signal of the discharge detection is sent to an arithmetic processing section 24 provided at a control section 10 at every detection of abnormal current. The arithmetic processing section 24 determines the time for prolonging the film formation of the substrate from the setting of the off time of the temporary power feeding to the electrodes at every detection of the discharge and the number of the generation times of the release determined from the number of generation times of the contact signals of the discharge detection in accordance with the set film forming program and prolongs and corrects the running time of the ion source by the required time from the standard running time during the film formation via a film forming time setting section 25. As result, the film thickness of the film formation is made uniform and the yield of products is improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ion beam sputtering apparatus for irradiating a target with an ion beam to form a film on a substrate.

[0002]

2. Description of the Related Art Conventionally, this type of ion beam sputtering apparatus is generally formed as shown in FIG. 5, and an ion source 2, a target 3 and a substrate 4 are provided in a chamber 1 which is evacuated to a vacuum. Then, the target 3 is irradiated with the ion beam 5 extracted from the ion source 2, and the sputtered particles 6 of the target 3 are deposited on the substrate 4 to form the film on the substrate 4.

At this time, the film thickness of the substrate 4 is determined by the ion beam energy, the ion beam amount (ion current amount) and the ion beam irradiation time.

By the way, the ion source 2 generates plasma by arc discharge based on thermionic emission or microwave feeding, and the plasma is generated from the plasma by an extraction electrode composed of an acceleration electrode and a deceleration electrode of positive and negative potentials and a ground electrode of earth potential. Extract the ion beam.

Further, particularly when it is used as a production machine and when the film formation of a plurality of substrates 4 is sequentially performed, the arc power supply necessary for generating the plasma is turned on and off by sequence control or the like.
The off state is repeated to control the irradiation of the ion beam 5 so that the film thickness of each substrate 4 becomes constant (uniform).

Furthermore, when the extraction electrode is contaminated by sputtered particles or the like due to continuous operation for a long time, and discharge occurs between the electrodes of the extraction electrode, based on the detection of this discharge, for example, a predetermined off time shorter than 1 second The power supply to the acceleration electrode and the deceleration electrode is turned off to stop the extraction of the ion beam 5 to protect the power source of the ion source 2.

[0007]

In the case of the above-mentioned conventional ion beam sputtering apparatus, which is used especially as a production machine, when the ion source 2 is continuously operated for a long time and a discharge is generated between the extraction electrodes, it is temporarily generated. However, the extraction of the ion beam 5 is stopped and the irradiation of the ion beam 5 onto the substrate 4 is interrupted.

On the other hand, the irradiation of the ion beam 5 on the substrate 4 is
When a preset time elapses, the sequence control or the like automatically ends. Therefore, there is a problem that the irradiation time of the ion beam 5 on the substrate 4 is reduced depending on the number of times the discharge is generated, the film thickness of the substrate 4 becomes thin, and a film having a predetermined film thickness cannot be formed on the substrate 4. As a result, the film thickness cannot be made uniform, and the product yield depends on the number of discharge occurrences of the extraction electrode of the ion source 2 and cannot be improved.

An object of the present invention is to make it possible to form a film having a predetermined film thickness regardless of whether the extraction electrode of the ion source is discharged.

[0010]

In order to achieve the above-mentioned object, in the ion beam sputtering apparatus according to claim 1 of the present application, the ion source electrode for the discharge of the discharge electrode of the ion beam is supplied to the electrode of the ion source. The extension time of the film formation on the substrate is determined by setting the power-off time and the number of times the discharge is detected, and the operating time of the ion source is extended and corrected by the extension time from the set film formation time.

Therefore, even if discharge of the extraction electrode of the ion beam occurs once or a plurality of times during the film formation due to continuous operation for a long time and a temporary stop of the extraction of the ion beam occurs, only the stop time is generated. The operation time of the ion source is lengthened and the film formation of the substrate is extended. At this time, the film thickness of the substrate becomes the same as when the ion beam is irradiated for the prescribed film formation time without the above-mentioned discharge.

Therefore, a film having a predetermined film thickness can be formed on the substrate regardless of whether the extraction electrode of the ion source is discharged. Further, in the ion beam sputtering apparatus according to claim 2 of this application, the amount of ion current corresponding to the amount of the ion boom is measured during film formation, and the time integrated value of the measured amount reaches the set total irradiation amount. Continue operating the ion source.

Therefore, when the extraction of the ion beam is temporarily stopped during the film formation due to the discharge of the extraction electrode of the ion beam, the operation of the ion source is continued until the total irradiation amount of the ion beam reaches the set amount. Substantially, the film formation time of the substrate is extended by the stop time of the extraction of the ion beam.

Therefore, also in this case, it is possible to form a film having a predetermined film thickness on the substrate regardless of whether or not the extraction electrode of the ion source is discharged.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION First and second embodiments of the present invention will be described with reference to FIGS. (First Mode) First, the first mode will be described.
The ion beam sputtering apparatus of the first embodiment is different from the conventional apparatus of FIG. 5 in that the ion source 7 having the configuration of FIG. 1 is provided instead of the ion source 2 of FIG.

The ion source 7 includes a housing portion 8 and a power source portion 9
And a control unit 10 formed by a sequencer or the like, each of which is formed as shown in FIG. 2, for example.

In FIG. 2, 11 is a casing forming the anode, 12 is a gas inlet formed on one side of the casing 11, 13 is a filament provided in the casing 11, 14
Is a filament power supply connected to both ends of the filament 3 led out of the housing 11, 15 is an arc power supply having an anode connected to the housing 11, and the cathode is a filament power supply 14
Connected to the cathode.

Reference numerals 16, 17, and 18 denote an acceleration electrode, a deceleration electrode, and a ground electrode, which are sequentially provided in the opening on the other side of the casing 11 from the filament 13 side, and the extraction electrode 1 for the ion beam 5 is provided.
9 is formed. Reference numeral 20 denotes an acceleration power supply connected in series to the cathode of the arc power supply 15, the anode of which is connected to the cathode of the arc power supply 15 and also to the acceleration electrode 16 via the resistor 21 having a high resistance value, and the cathode is grounded. Has been done. 22
Is a deceleration power supply whose cathode is connected to the deceleration electrode 17, and its anode is grounded. The ground electrode 18 is directly grounded.

Reference numeral 23 denotes a discharge detector for monitoring and detecting the occurrence of discharge between the extraction electrodes 19, which is composed of, for example, an overcurrent relay and has an abnormal current due to discharge of the acceleration electrode 16, the deceleration electrode 17, and the ground electrode 18. A contact signal for discharge detection is generated each time (overcurrent) is detected.

Reference numeral 24 denotes an arithmetic processing unit provided in the control unit 10, which monitors discharge detection of the extraction electrode 19 and each power source 14, 15, 20, based on the set film forming program.
Sequence control of film formation such as output control of 22 is performed. 25
Is a film formation time setting unit connected to the arithmetic processing unit 24,
The film formation time is set freely in the film formation timer 26 of the power supply unit 9, and the arc power supply 15 is turned on and off via the film formation timer 26.

Each power source 14, 15, 20, 22 is a so-called variable output power source, and its output becomes 0V when it is turned off.

Further, for example, a plurality of substrates 4 shown in FIG. 5 are mounted on a holder (not shown), and each substrate 4 is sequentially moved to a film forming position (position shown in the same figure) by rotation of the holder based on automatic control. When the film is formed by the film formation, the ion beam irradiation time for each substrate 4, that is, the standard operation time Ta of the ion source 7 once and the stop time Tb from the end of the operation to the start of the next operation are set in the film formation timer 26. It

When the operation of the apparatus is started, the power supplies 14, 15, 20, 22 are turned on by the control unit 10 to generate the outputs of the respective regulated voltages. At this time, the filament 13 is supplied from the filament power supply 14. The thermoelectrons emitted from the filament 13 are accelerated by the application of the arc voltage of the arc power supply 15, and the thermoelectrons are introduced into the housing 11 from the gas introduction port 12 To generate plasma 27.

Further, the acceleration voltage of the acceleration power supply 20 is applied to the acceleration electrode 16, the deceleration voltage of the deceleration power supply 17 is applied to the deceleration electrode 17, and the ion beam 5 is extracted from the plasma 27 by the action of the extraction electrode 19. The size (amount) of the ion beam 15 is adjusted by the current (filament current) of the filament power supply 14, for example.

On the other hand, the film formation timer 26 measures the operation time, and unless the operation time is corrected by discharge or the like, the arc is generated every time the set standard operation time Ta elapses and the film formation on the substrate 4 is completed. Turn off the power supply 15 and set its output to 0V,
The operation of the ion source 7 is stopped.

In this state, when the stop time Tb elapses and the next film formation on the substrate 4 is started, the film formation timer 26
Turns on the arc power supply 15 to operate the ion source 7 again. After that, by repeating the same operation, when there is no discharge or the like in a normal state, the ion beam 5, that is, the ion current is changed to T as shown in FIG.
It turns on and off in a constant cycle of a and Tb.

Next, when discharge occurs between the electrodes of the extraction electrode 9 during film formation due to electrode contamination or the like due to long-term operation, the discharge detector 23 immediately generates a contact signal for discharge detection, and this contact Upon the input of the signal, the arithmetic processing unit 24 temporarily turns off the acceleration power supply 20 and the deceleration power supply 22 to stop the extraction of the ion beam 5 and protect the power supply unit 9 from discharge.

Then, when the off time of power supply to the electrodes, for example, 1 second or less has elapsed from the occurrence of the discharge, the arithmetic processing unit 24 causes the acceleration power supply 20, if the discharge is not generated.
The deceleration power supply 22 is turned on, and when this is turned on, the ion beam 5
Are extracted again, and the film formation on the substrate 4 is restarted.

At this time, if the operation time of the film formation timer 26 remains the standard operation time Ta, when the standard operation time Ta elapses from the film formation start without considering the off time of the ion beam 5 due to the discharge. Further, the arc power supply 15 is turned off, the operation of the ion source 7 is stopped, the off time is shorter than when the film formation time of the substrate 4 is normal, and the film thickness of the substrate 4 becomes smaller than a predetermined film thickness.

In order to prevent this variation in film thickness,
When the occurrence of discharge is detected, the output of the filament power supply 14 is increased to increase the current amount of the ion beam 5 (beam current amount), and the film formation speed is substantially increased to obtain the same film thickness as in the normal case. It is possible to do it.

Instead of varying the output of the filament power supply 14, it is possible to increase the voltage of the acceleration power supply 20 (acceleration voltage) to increase the beam energy and increase the film formation speed.

However, if the output of the filament power source 14 or the acceleration power source 20 is varied by detecting the occurrence of discharge to control the film thickness, a complicated control circuit or the like is required for that purpose.

Therefore, in the device according to the first embodiment, the temporary OFF time of the power supply to the electrodes is set every time the discharge is detected, and the number of times the discharge is generated is determined from the number of times the contact signal for the discharge detection is generated. Therefore, the extension time Tδ of the film formation on the substrate 4 is
(= Off time × number of discharge occurrences) is determined, and the ion source 7
The operating time from the standard operating time Ta to the extension time T during film formation
Correct the extension by δ.

That is, as shown in FIG. 4, for example, discharge occurs between electrodes of the extraction electrode 9 at t _x during film formation, and power supply to the acceleration electrode 16 and the deceleration electrode 17 is stopped from t _x for the off time Tx. Then, when the extraction of the ion beam 5 stops, t _x
The discharge control contact signal causes the arithmetic control unit 24 to instruct the film formation time setting unit 25 to extend the film formation time, and the film formation time setting unit 25 sets the operation time of the film formation timer 26 at the present time each time the command is issued. The extension time is corrected to a time obtained by extending the off time Tx from the set time.

Due to this correction, in the case of FIG. 4, the number of discharge occurrences is one, so that the film formation time of the substrate 4 is increased from the standard operating time Ta to Ta '(= Ta + Tx), and at this time, substantially. Film formation time becomes standard operating time Ta,
The substrate 4 is formed under the same conditions as when there is no discharge, and the film thickness becomes a predetermined film thickness.

The operation time of the film formation timer 26 is reset to the standard operation time Ta every time the film formation of one substrate 4 is started. Therefore, the operating time of the ion source 7 in which the arc power supply 15 is turned on for each film formation of the substrate 4 is extended by the off time Tx according to the number of discharges between the extraction electrodes 9 and is corrected by a simple method. It is possible to form a film having a uniform film thickness set on each substrate 4 regardless of the occurrence of discharge.

(Second Mode) Next, the second mode will be described. In the apparatus of this embodiment, the amount of ion current corresponding to the amount of the ion beam 5 is measured during film formation, and the operation of the ion source 7 is continued until the time integrated value of the measured amount reaches the set total irradiation amount.

That is, the amount of ion current is set as the amount of current flowing through the accelerating power source 20, an ammeter 28 is provided on the cathode side of the accelerating power source 20 as shown in FIG. 2, and calculation is performed based on the measurement signal of the ammeter 28. The processing unit 24 monitors the amount of ion current.

On the other hand, the film formation time setting unit 25 and the film formation timer 26 shown in FIG. 2 are omitted, and a timer function is added to the arithmetic processing unit 24 so that the arithmetic processing unit 24 starts the film formation of each one substrate 4. The arc power supply 15 is turned on.

Then, the arithmetic processing unit 24 indirectly adds the time integrated value of the irradiation amount of the ion beam 5 by integrating and adding the measurement signals of the ammeter 28 during the film formation regardless of the presence or absence of a contact signal for discharge detection. Then, when the time integral value becomes equal to the preset total irradiation amount of the ion beam 5 during the normal operation time Ta in the normal state, the arc power supply 15 is turned off.

Then, in the case of automatic control operation, when the arc power supply 15 is turned off, for example, when the stop time Tb of the first embodiment has elapsed, the arc power supply 15 is turned on again to form the next film on the substrate 4. Move on to.

Therefore, in this case, the film formation on the substrate 4 is always performed with a constant total irradiation amount of the ion beam 5 regardless of whether the extraction electrode 9 is discharged or not, and as a result, the same as in the case of the first embodiment. The uniform film thickness set on each substrate 4 can be achieved. Needless to say, the ion current may be monitored by a method different from that shown in FIG.

[0043]

The present invention has the following effects. First, in the ion beam sputtering apparatus according to claim 1, discharge of the extraction electrode 19 of the ion beam 5 occurs once or a plurality of times during film formation by continuous operation for a long time, and temporary extraction of the ion beam 5 is performed. Even if the stop occurs, the operating time of the ion source 7 is extended by the stop time (off time) and the film formation of the substrate 4 is extended. At this time, the film thickness of the substrate 4 is regulated without discharge. The film forming time is the same as when the ion beam is irradiated, and it is possible to form a film having a predetermined film thickness on the substrate 4 regardless of whether the extraction electrode 19 of the ion source 7 is discharged. In this case, it is possible to make the film thickness of the formed film uniform and improve the product yield.

Further, in the ion beam sputtering apparatus according to the second aspect, even if the extraction of the ion beam 5 is temporarily stopped during film formation due to the discharge of the extraction electrode 19 of the ion beam 5, The operation of the ion source 7 is continued until the total irradiation amount of No. 5 reaches the set amount, and in this case also, the film formation of a predetermined film thickness can be performed regardless of the discharge of the extraction electrode 19. The same effect as in the case of such a device can be obtained.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a main part of an embodiment of the invention.

FIG. 2 is a detailed connection diagram of each part of FIG.

FIG. 3 is a waveform diagram for explaining film formation when there is no discharge.

FIG. 4 is a waveform diagram for explaining film formation when discharge is generated.

FIG. 5 is an explanatory diagram of a schematic configuration of a general ion beam sputtering apparatus.

[Explanation of symbols]

 3 Target 4 Substrate 5 Ion Beam 7 Ion Source 19 Extraction Electrode

Claims (2)

[Claims] 1. A film is formed on a substrate by irradiating a target with an ion beam extracted from an ion source, and detecting the discharge of an extraction electrode of the ion beam provided in the ion source during film formation. In an ion beam sputtering apparatus for temporarily turning off the power supply to the electrode of the ion source to stop the extraction of the ion beam, setting the off time of the power supply to the electrode for each detection of the discharge and the number of times the discharge is detected. The ion beam sputtering apparatus is characterized in that the extension time of the film formation is determined by and the operation time of the ion source is extended and corrected by the extension time from the set film formation time. 2. The film is formed during film formation by irradiating a target with an ion beam extracted from an ion source to form a film on a substrate, and detecting discharge of an extraction electrode of the ion beam provided in the ion source. In an ion beam sputtering apparatus that temporarily turns off the electrode power supply of the ion source to stop the extraction of the ion beam, measures the amount of ion current corresponding to the amount of the ion beam during film formation, and integrates the measured amount over time. The ion beam sputtering apparatus, wherein the operation of the ion source is continued until the value reaches a set total irradiation amount.