ELECTRON BEAM DEVICE AND METHOD FOR CONTROLLING AN ELECTRON BEAM DEVICE

Abstract

Electron beam apparatus, including: an electron gun (101) designed to emit an electron beam, an electron gun chamber (100) and a gas supply unit (104) designed to supply at least one of the substances hydrogen, oxygen, carbon monoxide and carbon dioxide to the electron gun chamber (100), characterized by the fact that a sputter ion pump (102) and a NEG pump (103) are connected to the electron gun chamber (100), the gas supply unit (104) contains a gas generation source (201) designed to generate the gas, and the gas generation source (201) is an alloy designed to enclose the gas.

Description

Technical field

[0001] The present invention relates to an electron beam device, represented by an electron microscope, and in particular to a technique for evacuating an electron gun chamber, in which an electron gun is provided, to an extreme high vacuum with a degree higher than that of an ultra-high vacuum of 10 -6 Pa up to 10 -8 Pa. Technical background

[0002] An electron microscope, which is an example of an electron beam instrument, is used to observe various samples with a fine structure and is particularly useful for dimensional measurement and defect inspection of a structure formed on a semiconductor wafer during the fabrication of a semiconductor device. To stabilize the number of electrons in an electron beam emitted by an electron gun, it is necessary to improve the vacuum level in the electron gun chamber where the electron gun is housed.

[0003] PTL 1 discloses an evacuation device for an extreme high vacuum, comprising a sputter ion pump (IP) and a non-evaporable getter (NEG) pump, in which an evacuation inducer is provided that induces the evacuation of gas through the IP. In particular, PTL 1 discloses that when the IP is temporarily stopped and then restarted in an extreme high vacuum state, a vacuum vessel or the like is vibrated by an ultrasonic vibrator to release the gas adsorbed on a surface of an element, and the gas is supplied as an evacuation inducer. Citation list for patent literature

[0004] PTL 1: Japanese Patent No. JP 3 926 206 B2 US 2011 / 0 101 238 A1 discloses an electron beam device with the features in the preamble of claims 1 and 12. Further, more conventional electron beam devices are described in DE 11 2016 007 160 B4, US 2015 / 0 054 398 A1 and in the technical article by F. Charbonnier “Developing and using the field emitter as a high intensity electron source”, Applied Surface Science 94 (1996), pages 26 - 43. Overview of the invention Technical problem

[0005] In PTL 1, however, the gas released as an evacuation inducer can contain hydrogen gas, which is a major component, and gas that is difficult to evacuate via the IP or the NEG pump. Furthermore, it can take a long time to reach the extreme high vacuum state after restarting the IP. If this takes a long time after restarting the IP, downtime of the electron beam equipment, for example, when the electron gun is being replaced, will be prolonged, hindering the semiconductor device manufacturing process.

[0006] One objective of the invention is to provide an electron beam device and a method for controlling the electron beam device that reduce the time required for an electron gun chamber to reach an extremely high vacuum state. A sputtering ion pump and a pump with a non-vaporizable getter are connected to the electron gun chamber. Solution to the problem

[0007] To achieve the above-described objective, the invention provides an electron beam device with the features of claim 1.

[0008] The invention further provides a method for controlling an electron beam device with the features of claim 12. Beneficial effect

[0009] According to the invention, it is possible to provide the electron beam device and a method for controlling the electron beam device, which reduces the time required for the electron gun chamber to reach a state of extreme high vacuum. The sputter ion pump and the pump with non-vaporizable getter are connected to the electron gun chamber. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is an overall configuration diagram of an electron beam device. [ Fig. 2] Fig. Figure 2 is a diagram showing an example of an electron gun chamber according to a first embodiment. [ Fig. 3] Fig. Figure 3 is a diagram showing an example of an electron gun chamber according to a second embodiment. [ Fig. 4] Fig. Figure 4 is a diagram showing an example of a material for a gas generation source according to the second embodiment. [ Fig. 5] Fig. Figure 5 is a diagram showing an example of an electron gun chamber according to a third embodiment. [ Fig. 6] Fig. Figure 6 is a diagram showing another example of the electron gun chamber according to the third embodiment. [ Fig. 7] Fig. Figure 7 is a diagram showing an example of an electron gun chamber according to a fourth embodiment, which, however, does not fall within the scope of protection of the present claims. [ Fig. 8] Fig. Figure 8 is a diagram showing an example of an electron gun according to a fifth embodiment. [ Fig. 9] Fig. Figure 9 is a diagram showing an example of an electron gun chamber according to a sixth embodiment. [ Fig. 10] Fig. Figure 10 is a diagram showing an example of a process flow according to the sixth embodiment. Description of the embodiments

[0010] The following describes embodiments of an electron beam device according to the invention with reference to the accompanying drawings. The electron beam device is a device that makes it possible to observe and process a sample by irradiating the sample with an electron beam, and it includes various devices such as a scanning electron microscope and a scanning transmission electron microscope. The scanning electron microscope, with which the sample can be observed using the electron beam, is described below as an example of the electron beam device. [First embodiment]

[0011] A complete configuration of a scanning electron microscope according to the present embodiment is described with reference to Fig. 1 described. The scanning electron microscope contains an electron gun chamber 100, a focusing and deflection chamber 110, a sample chamber 120 and a control unit 130.

[0012] Electron gun chamber 100 contains an electron gun 101, which emits an electron beam, and is connected to a sputter ion pump 102 and a pump 103 with a non-evaporable getter. Connecting the sputter ion pump 102 and the pump 103 with the non-evaporable getter evacuates the electron gun chamber 100 to an extreme high vacuum, the degree of which is higher than that of an ultra-high vacuum of 10 -6 Pa up to 10 -8Pa. The sputter ion pump 102 is also referred to as IP, and the pump 103 with non-vaporizable getter is also referred to as NEG pump. The electron gun chamber 100 is also connected to a gas supply unit 104, which supplies at least one of the substances hydrogen, oxygen, carbon monoxide, and carbon dioxide, as well as to 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 chamber 100 is given with reference to Fig. 2 described.

[0013] The focusing and deflection chamber 110 is evacuated by a first pump 112 and is evacuated separately from the electron gun chamber 100, which is connected via a first opening 111. A sputter ion pump, for example, is used for the first pump 112. A focusing lens (not shown) and a deflector (not shown) are provided in the focusing and deflection chamber 110, and the electron beam emitted by the electron gun 101 is focused or deflected.

[0014] Sample chamber 120 is evacuated by a second pump 122 and separately from the focusing and deflection chamber 110, which is connected via a second opening 121. A turbomolecular pump, for example, is used as the second pump 122. Sample chamber 120 contains a sample stage 124 on which a sample 123 is placed. The sample 123 is irradiated with an electron beam that is focused and deflected in the focusing and deflection chamber 110. Secondary electrons and reflected electrons emitted by the sample 123 upon irradiation with the electron beam are detected by a detector (not shown) located in the focusing and deflection chamber 110.

[0015] The control unit 130 is a device that controls every part of the scanning electron microscope and is, for example, a computer. The control unit 130 generates and displays an observation image based on a signal output by the detector.

[0016] The electron gun chamber 100 according to the present embodiment is described with reference to Fig. 2 described. The electron gun 101 provided in the electron gun chamber 100 is 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 emits electrons by applying a high voltage. The electron beam emitted by the electron gun 101 is accelerated by an accelerating voltage applied to an accelerating electrode (not shown).

[0017] The sputter ion pump 102 is a pump that evacuates a gas by means of a getter action of a clean, evaporated film formed by atoms of cathodes that are sputtered by ionized gas. The ionized gas is formed by ionizing gas molecules with electrons that move back and forth between the cathodes due to electric and magnetic fields as they travel in a spiral. An IP power supply 105 is connected to the sputter ion pump 102, and a high voltage is applied to generate the electric field. In the sputter ion pump 102, the gas is also evacuated by trapping the ionized gas within the cathodes. In the sputter ion pump 102, the ionization of the gas creates an evacuation effect, and therefore the evacuation rate decreases as the amount of residual gas decreases.the higher the vacuum level, and the final vacuum level is an ultra-high vacuum of 10. -8 Pa.

[0018] The pump 103 with non-vaporizable getter is a pump that evacuates a gas by trapping the gas approaching a surface through thermal purification of a metal with high chemical reactivity with the gas, such as titanium and zirconium, in an ultra-high vacuum. The pump 103 with non-vaporizable getter is equipped with a NEG heating unit 106 for heating. A NEG power supply 107 is connected to the NEG heating unit 106, and electrical power is supplied to enable the pump 103 with non-vaporizable getter to be heated. In a state where the ultra-high vacuum is reached by the sputtering ion pump 102, which performs a vacuum evacuation, the electrical power is supplied by the NEG power supply 107 to operate the pump 103 with non-evaporable getter, so that the electron gun chamber 100 reaches the extreme high vacuum.

[0019] Since the pump 103 with non-vaporizable getter can maintain its high evacuation rate even in ultra-high vacuum, the electron gun chamber 100 can achieve an extreme high vacuum with a vacuum level higher than that of ultra-high vacuum. However, its operating time is limited because the amount of gas captured is restricted by the surface area. This means that the evacuation rate of the pump 103 with non-vaporizable getter decreases with prolonged use or operation at a low vacuum level. For example, if the electron gun 101 is replaced, the pump 103 with non-vaporizable getter continues to operate from the time the sputter ion pump 102 is stopped until it is restarted, and the evacuation rate 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 pump 102 contains a gas that is difficult to evacuate for the sputter ion pump 102 or the pump 103 with non-vaporizable getter, the time to reach the extreme high vacuum will be long.

[0020] Therefore, in the present embodiment, the evacuation rate of pump 103 with non-vaporizable getter is not reduced by supplying a gas, which is easily evacuated by the sputter ion pump 102 or pump 103 with non-vaporizable getter, into the electron gun chamber 100 and restarting the sputter ion pump 102 in a short time. If the evacuation rate of pump 103 with non-vaporizable getter is not reduced, the time required to reach the extreme high vacuum can be shortened.

[0021] The gas supply unit 104 supplies the electron gun chamber 100 with at least one of the substances hydrogen, oxygen, carbon monoxide, and carbon dioxide, which are readily evacuated by the sputter ion pump 102 and the pump 103 with non-vaporizable getter. According to the present embodiment, the gas supply unit 104 comprises a gas generation source 201, a heating unit 202, and a heating power source 203. Each of these units is described below.

[0022] The gas generation source 201 is an element that produces at least one of the substances hydrogen, oxygen, carbon monoxide, and carbon dioxide, for example, an alloy, a hydride, an oxide, a carbon oxide, or a hydroxide that encapsulates the gas. It is desirable that the material of the gas generation source 201 be the same as that of the pump 103 with non-vaporizable getter, so that the gas produced by the gas generation source 201 becomes the gas that can be easily evacuated by the pump 103 with non-vaporizable getter. If both materials are the same, it is also desirable that the surface area of ​​the gas generation source 201 be smaller than that of the pump 103 with non-vaporizable getter, so that the amount of gas produced by the gas generation source 201 is less than the evacuation capacity of the pump 103 with non-vaporizable getter.

[0023] The heating unit 202 is a heater that warms the gas generation source 201 and raises its temperature until a temperature sufficient for gas generation is reached. The heating unit 202 heats the gas generation source 201 to generate the gas when the gas is not evacuated by the sputter ion pump 102, even though high voltage is applied by the IP power supply 105.

[0024] The heating power source 203 is a power source that supplies electrical power to the heating unit 202. The electrical power is supplied in such a way that the heating unit 202 heats the gas generation source 201. The amount of electrical power supplied to the heating unit 202 is set based on control performed by the control unit 130 and operation carried out by an operator.

[0025] According to the gas supply unit 104 in the present embodiment described above, the sputtering ion pump 102 can be restarted within a short time, for example, when the electron gun 101 is replaced. That is, if the sputtering ion pump 102 does not restart even though the IP power supply 105 applies the high voltage, the electrical power from the heating power source 203 is supplied to the heating unit 202 to heat the gas generation source 201. The gas produced by heating the gas generation source 201 then restarts the sputtering ion pump 102 within a short time, and therefore the evacuation rate of the pump 103 with non-vaporizable getter is maintained.Hydrogen, oxygen, carbon monoxide and carbon dioxide produced by the gas generation source 201 are gases that can be easily evacuated by the sputter ion pump 102 and the pump 103 with non-vaporizable getter, and therefore the time to reach the extreme high vacuum can be reduced while maintaining the evacuation rate of the pump 103 with non-vaporizable getter. [Second embodiment]

[0026] In the first embodiment, it was described that a gas for restarting the sputtering ion pump 102 is generated by heating the gas generation source 201. In the present embodiment, it is described that the gas for restarting the sputtering ion pump 102 is generated by irradiating the gas generation source 201 with light. The overall configuration of a scanning electron microscope is the same as that according to the first embodiment, and therefore a description of it is omitted.

[0027] The electron gun chamber 100 according to the present embodiment is described with reference to Fig. 3. The electron gun 101 is provided in the electron gun chamber 100, and the sputter ion pump 102, the pump 103 with non-vaporizable getter, and the gas supply unit 104 are connected as in the first embodiment. The electron gun 101, the sputter ion pump 102, and the pump 103 with non-vaporizable getter are the same as those according to the first embodiment. The gas supply unit 104 according to the present embodiment includes the gas generation source 201, a light source 301, and a transmission window 303. Since the gas generation source 201 is the same as that according to the first embodiment, the light source 301 and the transmission window 303 are described.

[0028] The light source 301 is a device that emits light 302 for generating the gas from the gas generation source 201 and is, for example, a light-emitting diode (LED). The light 302 emitted by the light source 301 to the gas generation source 201 is preferably selected to suit the material of the gas generation source 201. For example, as in Fig. As shown in Figure 4, the material of the gas generation source 201 is calcium carbonate or carboxylic acid. The light source 301 emits 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 produced. A material that produces at least one of the substances hydrogen, oxygen, carbon monoxide, and carbon dioxide when irradiated with ultraviolet rays can be used for the gas generation source 201. The light source 301 irradiates the gas generation source 201 with the light 302 to produce the gas when the gas is not evacuated by the sputter ion pump 102, even though a high voltage is applied from the IP power supply 105.

[0029] A lens that focuses the light 302 can be provided between the light source 301 and the gas generation source 201. The area illuminated by the light 302 can be controlled by moving the lens along the axial direction of the light 302. The position illuminated by the light 302 can be controlled by changing the direction of the light source 301. The amount of gas produced by the gas generation source 201 can be adjusted by controlling the area and position illuminated by the light 302. The amount of gas produced can be adjusted by controlling the output of the light source 301. The amount of gas produced is set based on control performed by the control unit 130 and operation by an operator.

[0030] The transmission window 303 is an element through which the light 302 from the light source 301 is transmitted and which seals the vacuum electron gun chamber 100. It is preferable to use a material with high transmittance for the light 302 for the transmission window 303. If the light source 301 is located inside the electron gun chamber 100, the transmission window 303 can be omitted.

[0031] According to the gas supply unit 104 in the present embodiment described above, the sputtering ion pump 102 can be restarted in a short time, as in the first embodiment, for example, if the electron gun 101 is replaced. That is, if the sputtering ion pump 102 does not restart even though the IP power supply 105 applies the high voltage, the light source 301 emits light 302 to generate the gas from the gas generation source 201. The gas generated by the gas generation source 201 restarts the sputtering ion pump 102 in a short time, and therefore an evacuation rate of the pump 103 with non-vaporizable getter is maintained.Hydrogen, oxygen, carbon monoxide and carbon dioxide produced by the gas generation source 201 are gases that are easily evacuated by the sputter ion pump 102 and the pump 103 with non-vaporizable getter, and therefore the time to reach an extreme high vacuum can be reduced while maintaining the evacuation rate of the pump 103 with non-vaporizable getter.

[0032] Since the gas is generated by irradiation with the light 302, the amount of gas generated for restarting the sputter ion pump 102 can be quickly adjusted according to the present embodiment. [Third embodiment]

[0033] It has been described that, in the first embodiment, a gas for restarting the sputtering ion pump 102 is generated by heating the gas generation source 201, and in the second embodiment by irradiating the gas generation source 201 with light 302. In the present embodiment, it is described that the gas for restarting the sputtering ion pump 102 is generated by irradiating the gas generation source 201 with charged particles. The overall configuration of a scanning electron microscope is the same as that according to the first embodiment, and therefore a description of it is omitted.

[0034] The electron gun chamber 100 according to the present embodiment is described with reference to Fig. 5. The electron gun 101 is provided in the electron gun chamber 100, and the sputter ion pump 102, the pump 103 with non-vaporizable getter, and the gas supply unit 104 are connected as in the first embodiment. The electron gun 101, the sputter ion pump 102, and the pump 103 with non-vaporizable getter are the same as those according to the first embodiment. The gas supply unit 104 according to the present embodiment includes the gas generation source 201, a charge particle source 501, and an acceleration power source 502. Since the gas generation source 201 is the same as that according to the first embodiment, the charge particle source 501 and the acceleration power source 502 are described.

[0035] The charge particle source 501 is a device that emits the charged particles used to generate the gas from the gas generation source 201 and is an electron source, such as an electron gun. The charge particle source 501 bombards the gas generation source 201 with the charged particles, for example, electrons, to generate the gas when the gas is not evacuated by the sputter ion pump 102, even though a high voltage is applied by the IP power supply 105.

[0036] An electromagnetic lens, which focuses the charged particles, can be provided between the charge particle source 501 and the gas generation source 201. A deflector, which deflects the charged particles, can also be provided. The amount of gas produced by the gas generation source 201 can be adjusted by controlling the area and position irradiated with the charged particles. The amount of gas produced can also be adjusted by controlling the output of the charge particle source 501.

[0037] The acceleration power source 502 is a circuit that applies a voltage between the charge particle source 501 and the gas generation source 201. The voltage applied by the acceleration power source 502 accelerates the charged particles emitted by the charge particle source 501. That is, the amount of gas produced by the gas generation source 201 can also be adjusted by controlling the voltage applied by the acceleration power source 502. The amount of gas produced is adjusted based on control performed by the control unit 130 and operation by an operator.

[0038] Another example of the electron gun chamber 100 according to the present embodiment is given with reference to Fig. 6 described. Fig. 6 is to replace the charge particle source 501 with electron gun 101. Fig. To use the gas generation source 201, the position of the gas generation source 201 was changed and a deflector 601 was provided. That is, an electron beam emitted by the electron gun 101 is deflected by the deflector 601, and the gas generation source 201, located near an optical axis 602 of the electron beam, is irradiated with the electron beam. An electrostatic deflector or an electromagnetic deflector is used. The electron gun 101 and the deflector 601 operate when the gas is not evacuated by the sputter ion pump 102, even though the high voltage is applied by the IP power supply 105, and irradiate the gas generation source 201 with the electron beam to generate the gas.

[0039] According to the gas supply unit 104 in the present embodiment described above, the sputtering ion pump 102 can be restarted in a short time, as in the first and second embodiments, for example, if the electron gun 101 is replaced. That is, if the sputtering ion pump 102 does not restart even though the IP power supply 105 applies the high voltage, the gas is generated from the gas generation source 201 by irradiating the gas generation source 201 with the charged particles from the charge particle source 501 or the electron beam from the electron gun 101. The gas generated by the gas generation source 201 then restarts the sputtering ion pump 102 in a short time, and therefore the evacuation rate of the pump 103 with non-vaporizable getter is maintained.Hydrogen, oxygen, carbon monoxide and carbon dioxide produced by the gas generation source 201 are gases that are easily evacuated by the sputter ion pump 102 and the pump 103 with non-vaporizable getter, and therefore the time to reach an extreme high vacuum can be reduced while maintaining the evacuation rate of the pump 103 with non-vaporizable getter.

[0040] According to the present embodiment, since a higher energy can be supplied to the gas generation source 201 by irradiating the gas generation source 201 with the charged particles, a cost-effective material with a low gas inclusion can be used for the gas generation source 201. [Fourth embodiment]

[0041] In the first through third embodiments, it was described that a gas for restarting the sputtering ion pump 102 was generated from the gas generation source 201 and supplied to the electron gun chamber 100. In the present embodiment, it is described that the gas for restarting the sputtering ion pump 102 is supplied from a gas cylinder. The overall configuration of a scanning electron microscope is the same as that according to the first embodiment, and therefore a description of it is omitted.

[0042] The electron gun chamber 100 according to the present embodiment is described with reference to Fig. 7. The electron gun 101 is provided in the electron gun chamber 100, and the sputter ion pump 102, the pump 103 with non-vaporizable getter, and the gas supply unit 104 are connected as in the first embodiment. The electron gun 101, the sputter ion pump 102, and the pump 103 with non-vaporizable getter are the same as those according to the first embodiment. The gas supply unit 104 according to the present embodiment comprises a gas cylinder 701, a line 702, and a valve 703.

[0043] The gas cylinder 701 is a container that encloses any gas consisting of hydrogen, oxygen, carbon monoxide, or carbon dioxide and is connected to the electron gun chamber 100 via line 702 and valve 703. The gas enclosed in the gas cylinder 701 is supplied to the electron gun chamber 100 through line 702 when valve 703 is open. That is, valve 703 opens and gas is supplied to the electron gun chamber 100 from cylinder 701 unless the gas is evacuated by the sputter ion pump 102, even when a high voltage is applied from the IP power supply 105. The amount of gas supplied to the electron gun chamber 100 is adjusted by the degree of opening of valve 703. The opening degree of the valve 703 is set based on control performed by the control unit 130 and actuation carried out by an operator.

[0044] According to the gas supply unit 104 in the embodiment described above, the sputtering ion pump 102 can be restarted within a short time, for example, when the electron gun 101 is replaced, as in the first through third embodiments. That is, if the sputtering ion pump 102 does not restart even though the IP power supply 105 applies the high voltage, the valve 703 opens to supply the gas from the cylinder 701 to the electron gun chamber 100. Since the sputtering ion pump 102 is restarted within a short time by any supplied hydrogen, oxygen, carbon monoxide, or carbon dioxide gas, an evacuation rate of the pump 103 with non-vaporizable getter is maintained.The gas supplied from cylinder 701 is a gas that is easily evacuated by the sputter ion pump 102 and the pump 103 with non-vaporizable getters, and therefore the time to reach an extreme high vacuum can be reduced while maintaining the evacuation rate of the pump 103 with non-vaporizable getters.

[0045] The gas supply unit 104, which contains a set of gas cylinder 701, pipe 702 and valve 703, can be a single set, as shown in Fig. 7 shown, or several sets can be connected to the electron gun chamber 100. [Fifth embodiment]

[0046] In the first through fourth embodiments, it was described that the gas supply unit 104 is connected to the electron gun chamber 100. Gas supplied by the gas supply unit 104 is used to restart the sputtering ion pump 102. In the present embodiment, it is described that the gas supply unit 104 is located near the sputtering ion pump 102. The overall configuration of a scanning electron microscope is the same as that of the first embodiment, and therefore a description of it is omitted.

[0047] The electron gun chamber 100 according to the present embodiment is described with reference to Fig. 8. The electron gun 101 is provided in the electron gun chamber 100, and the sputtering ion pump 102, the pump 103 with non-vaporizable getter, and the gas supply unit 104 are connected as in the first embodiment through the fourth embodiment. The present embodiment differs from the first embodiment through the fourth embodiment in that the gas supply unit 104 is located near the sputtering ion pump 102. More precisely, the gas supply unit 104 is located closer to the sputtering ion pump 102 than the pump 103 with non-vaporizable getter. With such an arrangement, the gas supplied by the gas supply unit 104 can reach the sputtering ion pump 102 without being trapped by the pump 103 with non-vaporizable getter, which is located further away than the sputtering ion pump 102.

[0048] According to the present embodiment, the sputtering ion pump 102 can be restarted more quickly, for example, when the electron gun 101 is replaced. That is, gas is supplied by the gas supply unit 104, located near the sputtering ion pump 102, if the sputtering ion pump 102 does not restart despite the IP power supply 105 applying a high voltage. Since the supplied gas reaches the sputtering ion pump 102 without being captured by the pump 103 with non-vaporizable getter, the sputtering ion pump 102 can be restarted more quickly. Consequently, the gas supplied by the gas supply unit 104 is not captured by the pump 103 with non-vaporizable getter. Therefore, the evacuation rate of the pump 103 with non-vaporizable getter is maintained.The gas supplied by the gas supply unit 104 is a gas that is easily evacuated by the sputter ion pump 102 and the pump 103 with non-vaporizable getter, and therefore the time to reach an extreme high vacuum can be reduced while maintaining the evacuation rate of the pump 103 with non-vaporizable getter. [Sixth embodiment]

[0049] In the first through fifth embodiments, it was described that the gas supply unit 104 supplies gas if the sputtering ion pump 102 does not restart, even though the IP power supply 105 applies a high voltage. In the present embodiment, it is described that the amount of gas supplied by the gas supply unit 104 is controlled based on an ionization current flowing through the sputtering ion pump 102. The overall configuration of a scanning electron microscope is the same as that described in the first embodiment, and therefore a description of it is omitted.

[0050] The electron gun chamber 100 according to the present embodiment is described with reference to Fig. 9. The electron gun 101 is provided in the electron gun chamber 100, and the sputter ion pump 102, the pump 103 with non-vaporizable getter, and the gas supply unit 104 are connected as in the first embodiment through the fifth embodiment. Differences between the present embodiment and the first through fifth embodiments are that an ammeter 901 is provided on the sputter ion pump 102, and the control unit 130 controls the gas supply unit 104 based on a reading from the ammeter 901.

[0051] The current meter 901 measures the ionization current flowing through the sputtering ion pump 102, to which the high voltage is applied by the IP power supply 105. The ionization current is a current generated when gas ionized by the sputtering ion pump 102 is atomized or captured by the cathode and serves as a guideline for the gas evacuation performed by the sputtering ion pump 102. That is, if the ionization current measured by the current meter 901 exceeds a predetermined threshold, it can be determined that the sputtering ion pump 102 has been restarted.

[0052] The control unit 130 controls the gas supply unit 104 based on the reading of the current meter 901. Specifically, when the IP power supply 105 applies high voltage to the sputtering ion pump 102, the control unit 130 supplies gas to the gas supply unit 104 if the reading of the current meter 901 is below the threshold value, and if the reading exceeds the threshold value, the gas supply is stopped. This control allows the gas supplied by the gas supply unit 104 to be reduced to the minimum amount required to restart the sputtering ion pump 102. By minimizing the gas supply to the gas supply unit 104, it is not necessary to over-operate the pump 103 with non-vaporizable getter.

[0053] An example of a processing sequence according to the present embodiment, when the electron gun 101 is used in the Fig. The configuration shown in 9 is replaced, with reference to Fig. 10 described. (S1001)

[0054] The control unit 130 stops an electron beam irradiation from the electron gun 101 based on an instruction from an operator. (S1002)

[0055] The control unit 130 switches off the IP power supply 105 to pause the sputter ion pump 102 based on the operator's instruction. (S1003)

[0056] The operator replaces electron gun 101. (S1004)

[0057] The control unit 130 switches on the IP power supply 105 to restart the sputter ion pump 102 based on the instruction from the operator. (S1005)

[0058] The control unit 130 determines, based on the reading from the current meter 901, whether the sputtering ion pump 102 has restarted, i.e., whether evacuation by the sputtering ion pump 102 has resumed. If evacuation by the sputtering ion pump 102 has not resumed, processing continues with S1006; if evacuation has resumed, processing continues with S1007. (S1006)

[0059] The control unit 130 supplies the gas from the gas supply unit 104 to the electron gun chamber 100. If the gas has already been supplied, the amount of gas supplied can be increased. (S1007)

[0060] The control unit 130 stops the supply of gas from the gas supply unit 104 to the electron gun chamber 100. If no gas is supplied, the present step is skipped.

[0061] The processing sequence described above makes it possible to reduce the time required by electron gun chamber 100 to reach an extreme high vacuum when electron gun 101 is replaced. Specifically, since sputter ion pump 102 can be restarted while minimizing the amount of gas supplied by gas supply unit 104, there is no need to over-operate pump 103 with non-vaporizable getter. Consequently, the evacuation rate of pump 103 with non-vaporizable getter is maintained, and the supplied gas is easily evacuated by both sputter ion pump 102 and pump 103 with non-vaporizable getter. Therefore, the time required to reach the extreme high vacuum is reduced.

[0062] As described above, several embodiments of the electron beam devices according to the invention have been described. The invention is not limited to the embodiments described above and can be embodied by modifying components without departing from any aspect of the invention. Several components disclosed in the embodiments described above can be combined appropriately, and some components can be removed, without leaving the scope of protection defined in the claims. Reference symbol list 100 electron gun chamber 101 Electron gun 102 Sputter ion pump 103 Pump with non-evaporable getter 104 Gas supply unit 105 IP power supply 106 NEG heating unit 107 NEG benefit provision 110 Focusing and deflection chamber 111 first opening 112 first pump 120 sample chamber 121 second opening 122 second pump 123 Sample 124 Sample table 130 control unit 201 Gas generation source 202 Heating unit 203 Heating power source 301 Light source 302 light 303 transmission windows 501 Charge particle source 502 Acceleration power source 601 Deflector 602 optical axis 701 Gas cylinders 702 Line 703 Valve 901 Current meter

Claims

[1] Electron beam apparatus, comprising: an electron gun (101) designed to emit an electron beam, an electron gun chamber (100) and a gas supply unit (104) designed to supply at least one of the substances hydrogen, oxygen, carbon monoxide and carbon dioxide to the electron gun chamber (100), characterized by , that a sputter ion pump (102) and a NEG pump (103) are connected to the electron gun chamber (100), the gas supply unit (104) contains a gas generation source (201) designed to generate the gas, and the gas generation source (201) is an alloy designed to enclose the gas. [2] Electron beam device according to claim 1, wherein the alloy is the same material as the NEG pump (103), and a surface area of ​​the alloy is smaller than a surface area of ​​the NEG pump (103). [3] Electron beam apparatus according to claim 1 or 2, wherein the gas generation source (201) is one of the following substances: a hydride, an oxide, a carbon oxide and a hydroxide. [4] Electron beam device according to one of the preceding claims, wherein the gas supply unit (104) further includes a heating source (202) configured to heat the gas generation source (201). [5] Electron beam device according to one of the preceding claims, wherein the gas supply unit (104) further includes a light source (301) configured to irradiate the gas generation source (201) with light. [6] Electron beam device according to claim 5, wherein the gas production source (201) is calcium carbonate or carboxylic acid, and the light source (301) is designed to emit infrared rays. [7] Electron beam device according to one of the preceding claims, wherein the gas supply unit (104) further includes a charge particle source (501) configured to irradiate the gas generation source (201) with charged particles. [8] Electron beam device according to one of the preceding claims, wherein the gas supply unit (104) is provided in a position which is closer to the sputter ion pump (102) than to the NEG pump (103). [9] Electron beam apparatus according to one of the preceding claims, wherein the sputter ion pump (102) includes a current meter (901) designed to measure an ionization current, and the gas supply unit (104) is controlled based on a measurement from the electricity meter (901). [10] Electron beam apparatus according to claim 9, wherein the gas supply unit (104) the gas is supplied based on the reading of the current meter (901) when it is determined that the gas is not being evacuated by the sputter ion pump (102), and The gas supply stops when it is detected that the gas is being evacuated by the sputter ion pump (102). [11] Electron beam device according to claim 10, wherein the gas supply unit (104) increases a supply quantity of the gas until it is determined that the gas is evacuated by the sputter ion pump (102). [12] Method for controlling an electron beam device comprising an electron gun (101) designed to emit an electron beam and an electron gun chamber (100), wherein the method includes a gas supply step in which at least one of the substances hydrogen, oxygen, carbon monoxide and carbon dioxide is supplied to the electron gun chamber (100) from a gas supply unit (104), characterized by , that a sputter ion pump (102) and a NEG pump (103) are connected to the electron gun chamber (100), the gas supply unit (104) contains a gas generation source (201) designed to generate the gas, and the gas generation source (201) is an alloy designed to enclose the gas.

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