Electron beam apparatus and method for controlling electron beam apparatus

The invention provides an electron beam apparatus that reduces a time required for an electron gun chamber to which a sputter ion pump and a non-evaporable getter pump are connected to reach an extreme high vacuum state. The electron beam apparatus includes an electron gun configured to emit an electron beam and the electron gun chamber to which the sputter ion pump and the non-evaporable getter pump are connected. The electron beam apparatus further includes a gas supply unit configured to supply at least one of hydrogen, oxygen, carbon monoxide, and carbon dioxide to the electron gun chamber.

TECHNICAL FIELD

The present invention relates to an electron beam apparatus represented by an electron microscope, and in particular, a technique for evacuating an electron gun chamber in which an electron gun is provided to an extreme high vacuum having a vacuum degree higher than that of an ultrahigh vacuum of 10−6Pa to 10−8Pa.

BACKGROUND ART

An electron microscope, which is an example of an electron beam apparatus, is used for observing various samples having a fine structure, and in particular, is used for dimensional measurement and defect inspection of a pattern formed on a semiconductor wafer in a manufacturing process of a semiconductor device. In the electron beam apparatus, in order to stabilize the amount of electrons of an electron beam emitted from an electron gun, it is required to improve a vacuum degree in an electron gun chamber in which the electron gun is provided.

PTL 1 discloses an extreme high vacuum evacuation device including a sputter ion pump (IP) and a non-evaporable getter (NEG) pump, in which an evacuation inducer that induces an evacuation of gas by the IP is supplied. In particular, PTL 1 discloses that, in an extreme high vacuum state, when the IP is temporarily stopped and then restarted, a vacuum vessel or the like is vibrated by an ultrasonic vibrator to release the gas adsorbed on a surface of a member and the gas is supplied as the evacuation inducer.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

However, in PTL 1, the gas released as the evacuation inducer may include hydrogen gas, which is a main component, and gas that is difficult to be evacuated by the IP or the NEG pump, and it may take a long time to reach the extreme high vacuum state after restarting the IP. If it takes a long time to reach the extreme high vacuum state after restarting the IP, a downtime of the electron beam apparatus becomes long when, for example, the electron gun is replaced, which hinders the manufacturing process of the semiconductor device.

An object of the invention is to provide an electron beam apparatus and a method for controlling the electron beam apparatus that reduce a time required for an electron gun chamber to reach an extreme high vacuum state. A sputter ion pump and a non-evaporable getter pump are connected to the electron gun chamber.

Solution to Problem

In order to achieve the above-described object, the invention provides an electron beam apparatus that includes an electron gun configured to emit an electron beam and an electron gun chamber to which a sputter ion pump and a non-evaporable getter pump are connected. The electron beam apparatus includes a gas supply unit configured to supply at least one of hydrogen, oxygen, carbon monoxide, and carbon dioxide to the electron gun chamber.

The invention provides a method for controlling an electron beam apparatus including an electron gun configured to emit an electron beam and an electron gun chamber to which a sputter ion pump and a non-evaporable getter pump are connected. The method includes a gas supply step of supplying at least one of hydrogen, oxygen, carbon monoxide, and carbon dioxide to the electron gun chamber.

Advantageous Effect

According to the invention, it is possible to provide the electron beam apparatus and a method for controlling the electron beam apparatus that reduce a time required for the electron gun chamber to reach an extreme high vacuum state. The sputter ion pump and the non-evaporable getter pump are connected to the electron gun chamber.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of an electron beam apparatus according to the invention will be described with reference to the accompanying drawings. The electron beam apparatus is an apparatus that allows a sample to be observed and processed by irradiating the sample with an electron beam, and includes various apparatuses such as a scanning electron microscope and a scanning transmission electron microscope. Hereinafter, as an example of the electron beam apparatus, the scanning electron microscope that allows the sample to be observed using the electron beam will be described.

First Embodiment

An overall configuration of a scanning electron microscope according to the present embodiment will be described with reference toFIG.1. The scanning electron microscope includes an electron gun chamber100, a focusing and deflecting chamber110, a sample chamber120, and a control unit130.

In the electron gun chamber100, an electron gun101that emits an electron beam is provided, and a sputter ion pump102and a non-evaporable getter pump103are connected. By connecting the sputter ion pump102and the non-evaporable getter pump103, the electron gun chamber100is evacuated to an extreme high vacuum having a vacuum degree higher than that of an ultrahigh vacuum of 10−6Pa to 10−8Pa. The sputter ion pump102is also called an IP, and the non-evaporable getter pump103is also called a NEG pump. The electron gun chamber100is also connected to a gas supply unit104that supplies at least one of hydrogen, oxygen, carbon monoxide, and carbon dioxide, and an auxiliary pump (not shown). The auxiliary pump is a pump that performs a vacuum evacuation from atmospheric pressure, for example, a dry pump or a turbomolecular pump. A detailed configuration of the electron gun chamber100will be described with reference toFIG.2.

The focusing and deflecting chamber110is evacuated by a first pump112and is evacuated differentially from the electron gun chamber100connected via a first opening111. For the first pump112, for example, a sputter ion pump is used. A focusing lens (not shown) and a deflector (not shown) are provided in the focusing and deflecting chamber110, and the electron beam emitted from the electron gun101is focused or deflected.

The sample chamber120is evacuated by a second pump122and evacuated differentially from the focusing and deflecting chamber110connected via a second opening121. As the second pump122, for example, a turbomolecular pump is used. A sample table124on which a sample123is placed is provided in the sample chamber120, and the sample123is irradiated with an electron beam focused and deflected in the focusing and deflecting chamber110. Secondary electrons and reflected electrons emitted from the sample123by irradiation with the electron beam are detected by a detector (not shown) provided in the focusing and deflecting chamber110.

The control unit130is a device that controls each part of the scanning electron microscope, and is, for example, a computer. The control unit130generates and displays an observation image based on a signal output by the detector.

The electron gun chamber100according to the present embodiment will be described with reference toFIG.2. The electron gun101provided in the electron gun chamber100is an electron source that emits the electron beam, and is, for example, a thermal electron source that emits thermal electrons by heating or a field emission electron source that field-emits electrons by applying a high voltage. The electron beam emitted from the electron gun101is accelerated by an acceleration voltage applied to an acceleration electrode (not shown).

The sputter ion pump102is a pump that evacuates a gas by a getter action of a clean vapor-deposited film formed by atoms of cathodes sputtered by ionized gas. The ionized gas is formed by ionizing gas molecules with electrons reciprocating between the cathodes while spiraling due to electric and magnetic fields. An IP power supply105is connected to the sputter ion pump102, and a high voltage for forming the electric field is applied. In the sputter ion pump102, the gas is also evacuated by capturing the ionized gas inside the cathodes. In the sputter ion pump102, an evacuation action is generated by the ionization of the gas, and thus the smaller residual gas, that is, the higher the vacuum degree, the lower the evacuation speed, and ultimate vacuum degree is an ultrahigh vacuum of 10−8Pa.

The non-evaporable getter pump103is a pump that evacuates a gas by capturing the gas approaching a surface by heat-cleaning a metal having a high chemical reactivity with the gas, such as titanium and zirconium in an ultrahigh vacuum. The non-evaporable getter pump103is provided with a NEG heating unit106for heating. A NEG power supply107is connected to the NEG heating unit106, and an electric power that allows the non-evaporable getter pump103to be heated is supplied. In a state in which the ultrahigh vacuum is reached by the sputter ion pump102performing a vacuum evacuation, the electric power is supplied from the NEG power supply107to operate the non-evaporable getter pump103, so that the electron gun chamber100reaches the extreme high vacuum.

Since the non-evaporable getter pump103can maintain the high evacuation speed even in the ultrahigh vacuum, the electron gun chamber100can reach an extreme high vacuum having a vacuum degree higher than that of the ultrahigh vacuum, but an operating time is limited since the capturing amount of the gas is limited by a size of a surface area. That is, the evacuation speed of the non-evaporable getter pump103decreases due to a long-term use or a use at a low vacuum degree. For example, when the electron gun101is replaced, the non-evaporable getter pump103continues operating from the time when the sputter ion pump102is paused to the time when the sputter ion pump102is restarted, and the evacuation speed decreases as the operating time increases. Therefore, it takes a long time to reach the extreme high vacuum. Even if a gas supplied to restart the sputter ion pump102contains a gas that is difficult for the sputter ion pump102or the non-evaporable getter pump103to evacuate, the time to reach the extreme high vacuum becomes long.

Therefore, in the present embodiment, by supplying a gas that is easily evacuated by the sputter ion pump102or the non-evaporable getter pump103to the electron gun chamber100and restarting the sputter ion pump102in a short time, the evacuation speed of the non-evaporable getter pump103is not reduced. If the evacuation speed of the non-evaporable getter pump103does not decrease, the time to reach the extreme high vacuum can be reduced.

The gas supply unit104supplies at least one of hydrogen, oxygen, carbon monoxide, and carbon dioxide, which is easily evacuated by the sputter ion pump102and the non-evaporable getter pump103, to the electron gun chamber100. The gas supply unit104according to the present embodiment includes a gas generation source201, a heating unit202, and a heating power source203. Each of the units will be described below.

The gas generation source201is a member that generates at least one of hydrogen, oxygen, carbon monoxide, and carbon dioxide, for example, an alloy, a hydride, an oxide, a carbon oxide, or a hydroxide that occludes the gas. It is desirable that a material of the gas generation source201is the same as that of the non-evaporable getter pump103so that the gas generated from the gas generation source201becomes the gas that can be easily evacuated by the non-evaporable getter pump103. Further, if both materials are the same, it is desirable that a surface area of the gas generation source201is smaller than that of the non-evaporable getter pump103so that the amount of a gas generated from the gas generation source201is less than an evacuation allowance of the non-evaporable getter pump103.

The heating unit202is a heater that heats the gas generation source201, and raises a temperature of the gas generation source201until a temperature at which the gas is generated is reached. The heating unit202heats the gas generation source201to generate the gas when the gas is not evacuated by the sputter ion pump102even though the high voltage is applied from the IP power supply105.

The heating power source203is a power source that supplies an electric power to the heating unit202. The electric power is supplied, so that the heating unit202heats the gas generation source201. The amount of electric power supplied to the heating unit202is adjusted based on a control executed by the control unit130and an operation performed by an operator.

According to the gas supply unit104in the present embodiment described above, the sputter ion pump102can be restarted in a short time, for example, when the electron gun101is replaced. That is, when the sputter ion pump102does not restart even though the IP power supply105applies the high voltage, the electric power is supplied from the heating power source203to the heating unit202to heat the gas generation source201. Then, the gas generated by heating the gas generation source201restarts the sputter ion pump102in the short time, and thus the evacuation speed of the non-evaporable getter pump103is maintained. Hydrogen, oxygen, carbon monoxide, and carbon dioxide that are generated from the gas generation source201are gases that are easily evacuated by the sputter ion pump102and the non-evaporable getter pump103, and thus along with maintaining the evacuation speed of the non-evaporable getter pump103, the time to reach the extreme high vacuum can be reduced.

Second Embodiment

In the first embodiment, it has been described that a gas for restarting the sputter ion pump102is generated by heating the gas generation source201. In the present embodiment, it will be described that the gas for restarting the sputter ion pump102is generated by irradiating the gas generation source201with a light. An overall configuration of a scanning electron microscope is the same as that according to the first embodiment, and thus a description thereof will be omitted.

The electron gun chamber100according to the present embodiment will be described with reference toFIG.3. In the electron gun chamber100, the electron gun101is provided, and the sputter ion pump102, the non-evaporable getter pump103, and the gas supply unit104are connected as in the first embodiment. The electron gun101, the sputter ion pump102, and the non-evaporable getter pump103are the same as those according to the first embodiment. The gas supply unit104according to the present embodiment includes the gas generation source201, a light source301, and a transmission window303. Since the gas generation source201is the same as that according to the first embodiment, the light source301and the transmission window303will be described.

The light source301is a device that emits a light302for generating the gas from the gas generation source201, and is, for example, a light emission diode (LED). The light302emitted from the light source301to the gas generation source201is preferably selected appropriately according to a material of the gas generation source201. For example, as shown inFIG.4, when the material of the gas generation source201is calcium carbonate or carboxylic acid, the light source301emits infrared rays. When calcium carbonate or carboxylic acid is irradiated with the infrared rays, a chemical change occurs due to heating and carbon dioxide is generated. The material that generates at least one of hydrogen, oxygen, carbon monoxide, and carbon dioxide by irradiation with ultraviolet rays may be used for the gas generation source201. The light source301irradiates the gas generation source201with the light302to generate the gas when the gas is not evacuated by the sputter ion pump102even though a high voltage is applied from the IP power supply105.

A lens that focuses the light302may be provided between the light source301and the gas generation source201. An area irradiated with the light302may be controlled by moving a position of the lens along an axial direction of the light302. A position irradiated with the light302may be controlled by changing a direction of the light source301. The amount of gas generated from the gas generation source201can be adjusted by controlling the area and the position irradiated with the light302. The amount of the generated gas may be adjusted by controlling an output of the light source301. The amount of the generated gas is adjusted based on a control executed by the control unit130and an operation performed by an operator.

The transmission window303is a member through which the light302is transmitted from the light source301and that seals the vacuum electron gun chamber100. It is preferable to use a material having a high transmittance of the light302for the transmission window303. When the light source301is provided in the electron gun chamber100, the transmission window303may be omitted.

According to the gas supply unit104in the present embodiment described above, the sputter ion pump102can be restarted in a short time as in the first embodiment when, for example, the electron gun101is replaced. That is, when the sputter ion pump102does not restart even though the IP power supply105applies the high voltage, the light source301emits the light302to generate the gas from the gas generation source201. Then, the gas generated from the gas generation source201restarts the sputter ion pump102in a short time, and thus an evacuation speed of the non-evaporable getter pump103is maintained. Hydrogen, oxygen, carbon monoxide, and carbon dioxide that are generated from the gas generation source201are gases that are easily evacuated by the sputter ion pump102and the non-evaporable getter pump103, and thus along with maintaining the evacuation speed of the non-evaporable getter pump103, a time to reach an extreme high vacuum can be reduced.

According to the present embodiment, since the gas is generated by irradiation with the light302, the amount of the generated gas for restarting the sputter ion pump102can be adjusted quickly.

Third Embodiment

It has been described that, a gas for restarting the sputter ion pump102is generated by heating the gas generation source201in the first embodiment, and by irradiating the gas generation source201with the light302in the second embodiment. In the present embodiment, it will be described that the gas for restarting the sputter ion pump102is generated by irradiating the gas generation source201with charged particles. An overall configuration of a scanning electron microscope is the same as that according to the first embodiment, and thus a description thereof will be omitted.

The electron gun chamber100according to the present embodiment will be described with reference toFIG.5. In the electron gun chamber100, the electron gun101is provided, and the sputter ion pump102, the non-evaporable getter pump103, and the gas supply unit104are connected as in the first embodiment. The electron gun101, the sputter ion pump102, and the non-evaporable getter pump103are the same as those according to the first embodiment. The gas supply unit104according to the present embodiment includes the gas generation source201, a charged particle source501, and an acceleration power source502. Since the gas generation source201is the same as that according to the first embodiment, the charged particle source501and the acceleration power source502will be described.

The charged particle source501is a device that emits the charged particles for generating the gas from the gas generation source201, and is an electron source such as an electron gun. The charged particle source501irradiates the gas generation source201with the charged particles, for example, electrons to generate the gas when the gas is not evacuated by the sputter ion pump102even though a high voltage is applied from the IP power supply105.

An electromagnetic lens that focuses the charged particles may be provided between the charged particle source501and the gas generation source201. A deflector that deflects the charged particles may be provided. The amount of the generated gas from the gas generation source201can be adjusted by controlling an area and a position irradiated with the charged particles. The amount of the generated gas may be adjusted by controlling an output of the charged particle source501.

The acceleration power source502is a circuit that applies a voltage between the charged particle source501and the gas generation source201. The voltage applied by the acceleration power source502accelerates the charged particles emitted from the charged particle source501. That is, the amount of the generated gas from the gas generation source201can also be adjusted by controlling the voltage applied by the acceleration power source502. The amount of the generated gas is adjusted based on a control executed by the control unit130and an operation performed by an operator.

Another example of the electron gun chamber100according to the present embodiment will be described with reference toFIG.6. InFIG.6, in order to use the electron gun101instead of the charged particle source501inFIG.5, a position of the gas generation source201is changed and a deflector601is provided. That is, an electron beam emitted from the electron gun101is deflected by the deflector601, and the gas generation source201arranged close to an optical axis602of the electron beam is irradiated with the electron beam. As the deflector, an electrostatic deflector or an electromagnetic deflector is used. The electron gun101and the deflector601operate when the gas is not evacuated by the sputter ion pump102even though the high voltage is applied from the IP power supply105, and irradiate the gas generation source201with the electron beam to generate the gas.

According to the gas supply unit104in the present embodiment described above, the sputter ion pump102can be restarted in a short time as in the first embodiment and the second embodiment when, for example, the electron gun101is replaced. That is, when the sputter ion pump102does not restart even though the IP power supply105applies the high voltage, the gas is generated from the gas generation source201by irradiating the gas generation source201with the charged particles from the charged particle source501or the electron beam from the electron gun101. Then, the gas generated from the gas generation source201restarts the sputter ion pump102in a short time, and thus the evacuation speed of the non-evaporable getter pump103is maintained. Hydrogen, oxygen, carbon monoxide, and carbon dioxide that are generated from the gas generation source201are gases that are easily evacuated by the sputter ion pump102and the non-evaporable getter pump103, and thus along with maintaining the evacuation speed of the non-evaporable getter pump103, a time to reach an extreme high vacuum can be reduced.

According to the present embodiment, since a higher energy can be given to the gas generation source201by irradiating the gas generation source201with the charged particles, an inexpensive material having a small occlusion of a gas can be used for the gas generation source201.

Fourth Embodiment

In the first embodiment to the third embodiment, it has been described that a gas for restarting the sputter ion pump102is generated from the gas generation source201and supplied to the electron gun chamber100. In the present embodiment, it will be described that the gas for restarting the sputter ion pump102is supplied from a gas cylinder. An overall configuration of a scanning electron microscope is the same as that according to the first embodiment, and thus a description thereof will be omitted.

The electron gun chamber100according to the present embodiment will be described with reference toFIG.7. In the electron gun chamber100, the electron gun101is provided, and the sputter ion pump102, the non-evaporable getter pump103, and the gas supply unit104are connected, as in the first embodiment. The electron gun101, the sputter ion pump102, and the non-evaporable getter pump103are the same as those according to the first embodiment. The gas supply unit104according to the present embodiment includes a gas cylinder701, a pipe702, and a valve703.

The gas cylinder701is a container that encloses any gas of hydrogen, oxygen, carbon monoxide, or carbon dioxide, and is connected to the electron gun chamber100via the pipe702and the valve703. The gas enclosed in the gas cylinder701is supplied to the electron gun chamber100through the pipe702when the valve703is opened. That is, the valve703is opened and the gas is supplied from the gas cylinder701to the electron gun chamber100when the gas is not evacuated by the sputter ion pump102even though a high voltage is applied from the IP power supply105. The amount of the gas supplied to the electron gun chamber100is adjusted by a degree of opening of the valve703. The degree of opening of the valve703is adjusted based on a control executed by the control unit130and an operation performed by an operator.

According to the gas supply unit104in the present embodiment described above, for example, when the electron gun101is replaced, the sputter ion pump102can be restarted in a short time as in the first embodiment to the third embodiment. That is, when the sputter ion pump102does not restart even though the IP power supply105applies the high voltage, the valve703is opened to supply the gas from the gas cylinder701to the electron gun chamber100. Then, since the sputter ion pump102is restarted in a short time by any of the supplied hydrogen, oxygen, carbon monoxide, or carbon dioxide gas, an evacuation speed of the non-evaporable getter pump103is maintained. The gas supplied from the gas cylinder701is a gas that is easily evacuated by the sputter ion pump102and the non-evaporable getter pump103, and thus along with maintaining the evacuation speed of the non-evaporable getter pump103, a time to reach an extreme high vacuum can be reduced.

The gas supply unit104including a set of the gas cylinder701, the pipe702, and the valve703may be a single set as shown inFIG.7, or a plurality of sets may be connected to the electron gun chamber100.

Fifth Embodiment

In the first embodiment to the fourth embodiment, it has been described that the gas supply unit104is connected to the electron gun chamber100. A gas supplied from the gas supply unit104is used for restarting the sputter ion pump102. In the present embodiment, it will be described that the gas supply unit104is provided in a vicinity of the sputter ion pump102. An overall configuration of a scanning electron microscope is the same as that according to the first embodiment, and thus a description thereof will be omitted.

The electron gun chamber100according to the present embodiment will be described with reference toFIG.8. In the electron gun chamber100, the electron gun101is provided, and the sputter ion pump102, the non-evaporable getter pump103, and the gas supply unit104are connected, as in the first embodiment to the fourth embodiment. The present embodiment differs from the first embodiment to the fourth embodiment in that the gas supply unit104is provided in a vicinity of the sputter ion pump102. More specifically, the gas supply unit104is provided at a position that is closer to the sputter ion pump102than is the non-evaporable getter pump103. With such an arrangement, the gas supplied from the gas supply unit104can reach the sputter ion pump102without being captured by the non-evaporable getter pump103provided at a position farther than the sputter ion pump102.

According to the present embodiment, for example, when the electron gun101is replaced, the sputter ion pump102can be restarted in a shorter time. That is, the gas is supplied from the gas supply unit104provided in the vicinity of the sputter ion pump102when the sputter ion pump102does not restart even though the IP power supply105applies a high voltage. Since the supplied gas reaches the sputter ion pump102without being captured by the non-evaporable getter pump103, the sputter ion pump102can be restarted in a shorter time. As a result, the gas supplied from the gas supply unit104is not captured by the non-evaporable getter pump103. Accordingly, an evacuation speed of the non-evaporable getter pump103is maintained. The gas supplied from the gas supply unit104is a gas that is easily evacuated by the sputter ion pump102and the non-evaporable getter pump103, and thus along with maintaining the evacuation speed of the non-evaporable getter pump103, a time to reach an extreme high vacuum can be reduced.

Sixth Embodiment

In the first embodiment to the fifth embodiment, it has been described that the gas supply unit104supplies a gas when the sputter ion pump102does not restart even though the IP power supply105applies a high voltage. In the present embodiment, it will be described that the amount of the gas supplied from the gas supply unit104is controlled based on an ionization current flowing through the sputter ion pump102. An overall configuration of a scanning electron microscope is the same as that according to the first embodiment, and thus a description thereof will be omitted.

The electron gun chamber100according to the present embodiment will be described with reference toFIG.9. In the electron gun chamber100, the electron gun101is provided, and the sputter ion pump102, the non-evaporable getter pump103, and the gas supply unit104are connected, as in the first embodiment to the fifth embodiment. Differences between the present embodiment and the first embodiment to the fifth embodiment are that, an ammeter901is provided on the sputter ion pump102, and the control unit130controls the gas supply unit104based on a measured value of the ammeter901.

The ammeter901measures the ionization current flowing through the sputter ion pump102to which the high voltage is applied by the IP power supply105. The ionization current is a current generated when a gas ionized by the sputter ion pump102spatters the cathode or is captured by the cathode, and serves as a guide for gas evacuation performed by the sputter ion pump102. That is, when the ionization current measured by the ammeter901exceeds a predetermined threshold value, it can be determined that the sputter ion pump102has restarted.

The control unit130controls the gas supply unit104based on the measured value of the ammeter901. Specifically, when the IP power supply105applies the high voltage to the sputter ion pump102, if the measured value of the ammeter901is less than the threshold value, the control unit130supplies the gas to the gas supply unit104, and if the measured value exceeds the threshold value, the gas supply is stopped. By such a control, the gas supplied from the gas supply unit104can be reduced to a minimum amount required for restarting the sputter ion pump102. By minimizing a gas supply amount of the gas supply unit104, it is not necessary to operate the non-evaporable getter pump103excessively.

An example of a flow of processing according to the present embodiment when the electron gun101is replaced in the configuration shown inFIG.9will be described with reference toFIG.10.

The control unit130stops an electron beam irradiation from the electron gun101based on an instruction from an operator.

The control unit130turns off the IP power supply105in order to pause the sputter ion pump102based on the instruction from the operator.

The operator replaces the electron gun101.

The control unit130turns on the IP power supply105in order to restart the sputter ion pump102based on the instruction from the operator.

The control unit130determines, based on the measured value of the ammeter901, whether the sputter ion pump102has restarted, that is, whether the evacuation has resumed by the sputter ion pump102. If the evacuation is not resumed by the sputter ion pump102, the processing proceeds to S1006, and if the evacuation is resumed, the processing proceeds to S1007.

The control unit130supplies the gas from the gas supply unit104to the electron gun chamber100. If the gas has already been supplied, the amount of the supplied gas may be increased.

The control unit130stops supply of the gas from the gas supply unit104to the electron gun chamber100. If no gas is supplied, the present step is skipped.

By the above flow of the processing, it is possible to reduce a time required for the electron gun chamber100to reach an extreme high vacuum when the electron gun101is replaced. That is, since the sputter ion pump102can be restarted while minimizing the amount of gas supplied from the gas supply unit104, it is not necessary to operate the non-evaporable getter pump103excessively. As a result, the evacuation speed of the non-evaporable getter pump103is maintained, and the supplied gas is a gas that is easily evacuated by the sputter ion pump102and the non-evaporable getter pump103. Accordingly, the time required to reach the extreme high vacuum is reduced.

As described above, a plurality of embodiments of the electron beam apparatus according to the invention has been described. The invention is not limited to the above embodiments, and can be embodied by modifying constituent elements without departing from a spirit of the invention. A plurality of constituent elements disclosed in the above embodiments may be combined as appropriate. Further, some constituent elements may be deleted from all the constituent elements shown in the above embodiments.

REFERENCE SIGN LIST