JPH09134698A - Ion beam machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To previously prevent machining failure by detecting abnormality of neutralization. SOLUTION: A normal range of a neutralizing electric current is prestored in a memory 103. A control device 102 actuates a power source 19, and flows the neutralizing electric current to a filament 18. At this time, a sensor 21 detects a value of the neutralizing electric current flowing in the filament 18, and output it to the control device 102. A processor 104 of the control device 102 obtains a normal range of the neutralizing electric current from the memory 103. Whether or not an output value from the sensor 21 falls within this normal range is judged. When it is outside of the range, pullout of an ion beam (b) is stopped. Therefore, machining failure caused by neutralizing failure can be previously prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion beam processing apparatus capable of performing fine processing using an ion beam.

[0002]

2. Description of the Related Art An ion beam processing apparatus performs milling processing by irradiating a sample with an ion beam.

An ion source of an ion beam processing apparatus draws a predetermined gas into a plasma in a vacuum container, and accelerates / decelerates the ions in the plasma by two electrodes to which an electric field is applied, thereby extracting the ion beam as an ion beam. ing. The control of the ion beam is performed by setting the acceleration voltage and the acceleration current applied to the electrodes.

When the ion beam thus extracted is directly applied to the sample made of an insulator, the surface of the sample is charged by the charge of the ion beam b, and the ion beam does not hit the sample ( See FIG. 2). That is, the milling process cannot be performed.

Therefore, in general, the ion beam is neutralized before irradiating the sample. Neutralization is performed by emitting electrons from the neutralizer. In the case of a filament type neutralizer, a filament is arranged in a straight line or in a V shape so as to intersect with the ion beam extracted to the vacuum chamber (processing chamber) side, and a predetermined current (neutralizing current) is applied to this filament. ), Thermionic electrons are emitted (see FIG. 3). The neutralizing current is changed according to the acceleration current used for extracting the ion beam.

[0006]

In the above filament type neutralizer, if the filament is grounded due to some trouble, the neutralizing current that should flow through the filament also flows to the ground side. Then, the current flowing through the filament is reduced, and thermoelectrons cannot be sufficiently generated. In such a case, since the neutralization is not sufficiently performed, the surface of the sample is charged (charge-up) and the milling process cannot be performed. Such a situation (grounding of the neutralizer filament) often occurs, for example, when the filament 18 is in contact with the vacuum chamber 1 due to poor insulation at the terminal 20 as shown in FIG.

It is an object of the present invention to provide an ion beam processing apparatus capable of reliably performing milling processing by monitoring neutralization.

[0008]

The present invention has been made to achieve the above object. As a first aspect thereof, a vacuum chamber and an ion beam generating apparatus for generating an ion beam in the vacuum chamber are provided. Means, a neutralizing means for neutralizing the ion beam, and an operating state of the neutralizing means,
There is provided an ion beam processing apparatus comprising: a control unit that stops the generation of the ion beam by the ion beam generation unit when an abnormality is found in its operating state.

The neutralizing means includes a filament installed on the path of the ion beam, and a power supply circuit for supplying a current to the filament, and the control means is a sensor for detecting the value of the current flowing through the filament. And a storage means storing control information indicating a normal range of the current, the detection result of the sensor and the normal range are compared, and as a result of the comparison, when the current is out of the normal range, May include a stopping means for stopping the generation of the ion beam by the ion beam generating means.

Input means for receiving an input of the ion beam generation condition is further provided, and the ion beam generation means operates in accordance with the input generation condition, and the control information includes the generation condition of the generation condition. The normal range is defined according to the contents, and the stopping means compares the normal range defined corresponding to the contents of the occurrence condition set at that time with the detection result. Is preferably performed.

The generation condition may be an acceleration current of the ion beam.

When the control means finds an abnormality,
It is preferable to further include an informing means for informing the user of that fact.

The operation will be described.

The ion beam generating means generates an ion beam in the vacuum chamber. The neutralizing means neutralizes the ion beam.

At this time, the control means monitors the operating state of the neutralizing means, and if there is an abnormality, stops the generation of the ion beam. Further, the notification means notifies that effect. For example, when the neutralizing means is a filament type, the sensor detects the value of the current flowing through the filament. The stopping means determines whether the detected value is within a predetermined normal range. If it is out of the normal range, the generation of the ion beam is stopped. The value of the current flowing through the filament is preferably defined according to the ion beam generation conditions (for example, acceleration current). Naturally, the determination is performed on the normal range defined corresponding to the occurrence condition set at that time.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the ion beam processing apparatus of this embodiment includes a vacuum chamber 1, a sample holder 2 arranged in the vacuum chamber 1, an ion source, a neutralizer, and a controller 102. It consists of

The ion source includes a filament power source 6, an arc power source 8, an acceleration electrode 10, a deceleration electrode 11, an acceleration power source 12,
It is composed of a deceleration power supply 13. Each part constituting the ion source is attached to the wall surface of the vacuum chamber 1.

The filament 7 is made of W, Ta or the like. The filament power source 6 is for generating thermoelectrons by passing a current through the filament 7.
The thermoelectrons ionize the gas in the chamber 1,
A plasma is generated. The filament power supply 6 is configured to operate according to an instruction from the control device 102.

The arc power source 8 is for maintaining plasma by passing an arc current between the filament 7 and the anode 9. The arc power source 8 is a control device 102.
It is configured to operate according to the instructions from.

Acceleration electrode 10, deceleration electrode 11, acceleration power supply 1
2. The deceleration power supply 13 is for extracting the ions in the plasma as an ion beam. Acceleration power supply 12,
The deceleration power supply 13 is configured to operate according to an instruction from the control device 102.

The neutralizer comprises a filament 18,
The neutralizer power source 19, the neutralizer introduction terminal 20, and the current sensor 21. A current (neutralize current) is passed through the filament 18 by the neutralizer power supply 19 to generate thermoelectrons. The neutralizer power supply 19 is connected to the control device 102.
The energization state (for example, the magnitude of the neutralizing current, energization / non-energization, etc.) can be changed in accordance with an instruction from. The current sensor 21 is the filament 18
It is for detecting the current value actually flowing in the. The current sensor 21 outputs the detection result to the control device 102. The detection result is used by the control device 102 to determine whether or not the neutralizer is operating normally.

The filament 18 is installed in the vacuum chamber 1 by a neutralizer introduction terminal 20.

The controller 102 controls and controls the entire ion beam processing apparatus. The control device 102 of this embodiment includes a microprocessor 104 and a memory 10.
3 and various data and programs stored in the memory 103. Various functions of the control device 102 are realized by the microprocessor 104 executing this program. The controller 102 operates the ion source and the neutralizer described above under operating conditions (for example,
It has a function to instruct acceleration voltage, acceleration current, magnitude of nutrize current) and control its operation. Further, it has a function of judging whether or not the neutralization is normally performed (or whether or not the neutralization can be normally performed) based on the neutralizing current. The normal range of the neutralizing current required for the judgment is stored in the memory 103 in advance. The optimum value of the neutralization current differs depending on the acceleration current. Therefore, this normal range is also defined for each set value of the acceleration current. Generally, the larger the set value of the acceleration current, the larger the neutralization current.

In addition to this, the control device 102 sets various condition values (for example, acceleration current and acceleration voltage) to the input device 1.
It is configured to be accepted through 01 and held in the memory 103. Further, the status of the device is displayed on the display device 105 as needed.

Although not shown in FIG. 1, other devices (eg, vacuum gauge, vacuum pump) that are naturally provided as an ion beam processing apparatus are also provided.

The "ion beam generating means" referred to in the claims means the control device 10 in this embodiment.
2, a filament power supply 6, a filament 7, an arc power supply 8 and the like. The "neutralizing means" means the filament 18 and the neutralizer power source 1.
9 corresponds to the control device 102. The “control means” corresponds to the control device 102 and the current sensor 21. The “filament” corresponds to the filament 18. The “power supply circuit” corresponds to the neutralizer power supply 19. The “sensor” corresponds to the current sensor 21. "Input means"
Corresponds to the input device 101. What is "memory means"?
It corresponds to the memory 103. The "stop means" is realized by a microprocessor and a program executed by the microprocessor. The “notifying means” corresponds to the display unit 105.

Next, the procedure and operation of milling will be described.

The user operates the input device 101 to previously specify various conditions (for example, the flow rate of the processing gas, the current flowing through the acceleration electrode 10 and the deceleration electrode 11 and the voltage).
The designated value is held in the memory 103 of the control device 102.

After holding the sample s in the sample holder 2, the user starts the processing operation. Then, the control device 10
2 operates the vacuum pump to exhaust the air in the vacuum chamber 1 from the exhaust port 4.

When the inside of the vacuum chamber 1 reaches a predetermined degree of vacuum, the control device 102 operates the flow rate controller 15 to introduce the processing gas filled in the cylinder 16 into the vacuum chamber 1 through the gas inlet 14. . The flow rate of the processing gas in this case is a value specified in advance.

Subsequently, the control device 102 controls the power sources 6, 8,
Activate 12, 13, and 19. The setting (for example, current and voltage) of each power supply is a value designated by the user in advance.

First, the controller 102 operates the filament power supply 6 to supply a current (hereinafter referred to as "filament current") to the filament 7. Then, the filament 7 generates heat and starts emitting thermoelectrons. The thermoelectrons collide with the molecules of the processing gas introduced into the vacuum chamber 1 to ionize the processing gas (that is, generate plasma). Then, the control device 102 operates the arc power supply 8 to cause an arc current to flow between the filament 7 and the anode 9, thereby maintaining the generated plasma.

Next, the controller 102 operates the acceleration power supply 12 and the deceleration power supply 13 to apply electric fields to the acceleration electrode 10 and the deceleration electrode 11, respectively. As a result, the ions in the plasma are extracted as the ion beam b toward the sample s. In order to stably extract the ion beam b, it is necessary to keep the plasma density constant. Therefore, the control device 102 maintains the plasma density constant by controlling the filament current and the arc current.

While the ion beam b is being extracted, the control device 102 operates the neutralizer power supply 19 to cause the neutralizing current to flow through the filament 18. The value of the neutralizing current is separately determined according to the accelerating current applied to the accelerating electrode 10 and stored in the memory 103.

The controller 102 stores the normal range of the neutralizer current under the set conditions at that time in the memory 103.
Read from At that time, the value (actually measured value) of the neutralizing current that is actually flowing is acquired based on the output value of the current sensor 21. Then, the microprocessor 104 determines whether or not the measured value is within the normal range (in other words, normal or abnormal). When the detected value is below the lower limit of the normal range (abnormal), the thermoelectrons are less likely to be emitted from the filament 18, and the neutralization becomes insufficient. On the contrary, when the upper limit is exceeded (abnormal), the amount of emitted thermoelectrons is too large. Also, in this state,
The filament life will be shortened. As a result of the judgment,
If the detected value is within the normal range, the milling process is performed until the preset machining time. On the other hand, when the detected value is not within the normal range, the control device 102 immediately stops the operations of the power supplies 6, 8, 12, 1319 and the flow meter 15. Thereby, the extraction of the ion beam b is stopped and the milling process is interrupted. In addition, an alarm is output on the display unit 105 to inform the user of the situation.

According to the embodiment described above, since the abnormality of neutralization can be detected, it is possible to prevent the defective milling process.

[0038]

According to the ion beam processing apparatus of the present invention, it is possible to prevent milling processing defects due to abnormal neutralization.

[Brief description of the drawings]

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

FIG. 2 shows an ion beam that has not been neutralized,
It is a schematic diagram which shows a mode when a sample of an insulator is irradiated.

FIG. 3 is a schematic diagram showing a state in which a sample made of an insulator is irradiated with a neutralized ion beam.

FIG. 4 is a schematic diagram showing a state in which the neutralization current flowing through the filament is insufficient due to the filament being grounded, and the neutralization is insufficient.

[Explanation of symbols]

1 ... Vacuum chamber, 2 ... Sample holder, 6 ... Filament power supply, 7 ... Filament, 8 ... Arc power supply, 9 ... Anode, 10 ... Acceleration electrode, 11 ... Deceleration electrode, 12 ... Acceleration Power supply, 13 ... deceleration power supply, 18 ...
Neutralizer filament, 19 ... Neutralizer power supply, 20 ... Neutralizer introduction terminal, 101
..Input device 102..Control device 103..Memory 104..Microprocessor 105..Display unit b..ion beam s ..

Claims (5)

[Claims] 1. A vacuum chamber, an ion beam generating means for generating an ion beam in the vacuum chamber, a neutralizing means for neutralizing the ion beam, and an operation state of the neutralizing means is monitored and operated. An ion beam processing apparatus comprising: a control unit that stops generation of an ion beam by the ion beam generation unit when an abnormality is found in the state. 2. The neutralizing means includes a filament installed on the path of the ion beam, and a power supply circuit for supplying a current to the filament, and the control means detects the value of the current flowing through the filament. The sensor, the storage means storing the control information indicating the normal range of the current, the detection result of the sensor and the normal range are compared, and as a result of the comparison, the current is out of the normal range. The ion beam processing apparatus according to claim 1, further comprising: a stopping unit that stops the generation of the ion beam by the ion beam generating unit. 3. The apparatus further comprises an input means for receiving an input of the ion beam generation condition, wherein the ion beam generation means operates in accordance with the input generation condition, and the control information includes the generation information. The normal range is defined according to the content of the condition, and the stop means is between the normal range defined corresponding to the content of the occurrence condition set at that time and the detection result, The ion beam processing apparatus according to claim 2, wherein the comparison is performed. 4. The ion beam processing apparatus according to claim 3, wherein the generation condition is an acceleration current of the ion beam. 5. When the control means finds an abnormality,
The ion beam processing apparatus according to claim 1, further comprising an informing unit for informing the user of that fact.