JP2019075390A - Ion beam device and operation method of the same - Google Patents

Abstract

To make compatible both of increase of conductance under rough vacuum evacuation and reduction of a diameter of an extraction electrode hole from a viewpoint of increase of current of ions in a gas field ionization ion source.SOLUTION: A field ionization ion source 1 has a mechanism for making conductance for vacuum-evacuating a gas molecule ionization chamber 15 variable. That is, the conductance for vacuum-evacuating the gas molecule ionization chamber 15 is variable in both cases when an ion beam is extracted from the gas molecule ionization chamber 15 and when no ion beam is extracted. A lid 32 serving as a part of a member constituting the mechanism for making the conductance variable is formed of bimetallic alloy, whereby the conductance is variable with respect to temperature of the gas molecule ionization chamber 15 such that the conductance is relatively small at relatively low temperature, and relatively large at relatively high temperature.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a gas field ionization ion source for generating ions, and a charged particle microscope for observing the surface or the inside of a sample such as a semiconductor device or a new material. The present invention also relates to a combined apparatus of an ion beam processing apparatus and a charged particle microscope, and a combined apparatus of an ion beam microscope and an electron microscope. The present invention also relates to an analysis / inspection apparatus to which an ion beam microscope and an electron microscope are applied.

  The structure of the sample surface can be observed by irradiating the sample while scanning the electrons and detecting secondary charged particles emitted from the sample. This is called a scanning electron microscope (hereinafter referred to as SEM). On the other hand, it is possible to observe the structure of the surface of the sample by irradiating the sample while scanning the ion beam and detecting secondary charged particles emitted from the sample. This is called a scanning ion microscope (hereinafter referred to as SIM). In particular, when the sample is irradiated with a light ion species having a mass such as hydrogen, helium, etc., the sputtering action becomes relatively small, which is suitable for observing the sample.

  Here, since the excitation region of secondary electrons due to hydrogen or helium ions entering the sample surface is localized to the sample surface as compared to electron irradiation, the SIM image is more sensitive to polar sample surface information than the SEM image. Is expected. Furthermore, from the viewpoint of a microscope, ions are heavier than electrons, so that the diffraction effect can be neglected in the beam focusing, and an extremely deep image of the focal depth can be obtained.

  In addition, by irradiating the sample with an electron or ion beam and detecting electrons or ions transmitted through the sample, it is possible to obtain information reflecting the internal structure of the sample. These are called transmission electron microscopes or transmission ion microscopes. In particular, if the sample is irradiated with a light ion species such as hydrogen, helium, etc., the rate of permeation through the sample becomes large, which is suitable for observation.

  The gas electrolytic ionization ion source is expected to be a fine beam due to the narrow energy width of the ions and the small size of the ion source, and is a suitable ion source for the above scanning ion microscope and transmission ion microscope. Patent Document 1 discloses that the ion source characteristic is improved by using an emitter tip having a minute projection at the tip of the emitter tip of the gas electrolytic ionization ion source. Further, as an example of preparation of the minute projection of the tip of the emitter tip, it is disclosed in Non-Patent Document 1 that the second tip different from the emitter tip material is used.

  In addition, Non-Patent Document 2 discloses a scanning ion microscope equipped with a gas electrolytic ionization ion source that releases helium ions.

  Further, Patent Document 2 discloses a gas electrolytic ionization ion source in which a cylindrical liquid nitrogen container is disposed so as to surround an ion generation part and the like. This document is provided with heating means for degassing the atmosphere side of the vacuum vessel of the gas electrolytic ionization ion source, a cooling vessel for cooling the vacuum vessel outside the heating means, etc. A reduced gas electrolytic ionization ion source is disclosed.

  Further, Patent Document 3 discloses a changeover switch in which a high voltage lead-in wire for an extraction electrode is connected to a high voltage lead-in wire for an emitter tip, and so-called conditioning forcible discharge treatment between an ion source outer wall and an emitter tip. A gas electrolytic ionization ion source is disclosed that can prevent discharge between the emitter tip and the extraction electrode after processing. In addition, there is an example using processing that applies the action of emitting particles from a sample by irradiating the sample with an ion beam and the sputtering action of the ions. The sample can also be finely processed. At this time, it is preferable to use a focused ion beam apparatus (hereinafter referred to as FIB) using a liquid metal ion source (hereinafter referred to as LMIS). Also, in recent years, a combined machine FIB-SEM apparatus of SEM and focused ion beam has come to be used. In this FIB-SEM apparatus, the cross section can be SEM-observed by irradiating the FIB to form a square hole at a desired location.

  For example, Patent Document 4 proposes an apparatus for observing and analyzing defects and foreign matter by forming a square hole in the vicinity of an abnormal part of a sample by FIB and observing the cross section of the square hole with a SEM device. There is.

  Further, Patent Document 5 proposes a technique for extracting a minute sample for transmission electron microscope observation from a bulk sample using an FIB and a probe.

Japanese Patent Application Publication No. 58-85242 Japanese Patent Laid-Open Publication No. 63-216249 Japanese Patent Laid-Open Publication No. 1-221847 Patent Publication 2002-150990 International Patent Publication WO 99/05506

H.-S. Kuo, I.-S. Hwang, T.-Y. Fu, J.-Y. Wu, C.-C. Chang, and T. T. Tsong, Nano Letters 4 (2004) 2379. J. Morgan, J. Notte, R. Hill, and B. Ward, Microscopy Today, July 14 (2006) 24

In an ion microscope using a field ionization ion source, if an ion beam with a large current density can be obtained on the sample, the sample can be observed at a high signal / noise ratio. In order to obtain a larger current density on the sample, the larger the ion emission angular current density of the field ionization ion source, the better. In order to increase the ion radiation angular current density, the pressure of the ion material gas introduced into the emitter tip chamber is increased to about 10 ^-2 to 10 Pa. The introduced gas is differentially exhausted through the hole of the extraction electrode. In order to vacuum rough the gas molecule ionization chamber, it is desirable that the hole diameter be large. However, when the pressure of the ion source gas is increased to 1 Pa or more when the hole of the extraction electrode is large, the degree of vacuum outside the gas molecule ionization chamber is degraded, and the ion beam collides with the neutral gas and is neutralized Therefore, the ion current is reduced. In addition, when the number of gas molecules outside the gas molecule ionization chamber increases, gas molecules that collide with the radiation shield or vacuum vessel wall at a higher temperature than the gas molecule ionization chamber collide with the gas molecule ionization chamber, thereby causing the gas molecule ionization chamber The problem is that the ion current is reduced due to the temperature rise of the In the gas field ionization ion source, the coexistence of the increase in the conductance at the time of rough vacuum and the reduction in diameter of the lead-out electrode hole from the viewpoint of increasing the current of ions is the first subject of the present invention.

  In addition, when impurity molecules are adsorbed on the emitter tip in the gas field ionization ion source, ions may be emitted from that point, and there is also a problem that the ion emission from the tip of the emitter tip is destabilized. That is, the second object of the present invention is to reduce the amount of impurities around the emitter tip as much as possible, that is, to increase the vacuum of the gas molecule ionization chamber.

  In order to obtain a large amount of ion current in the gas field ionization ion source, it is important to increase the density of gas molecules near the tip. The density of gas molecules per unit pressure is inversely proportional to the temperature of the gas, and it is important to cool the gas with the emitter tip. Since the gas field ion source generally needs to be joined with a high temperature region and a good conductor in order to apply a high voltage to the emitter tip, or to face the high temperature ion beam lens, the emitter tip may be frozen to a very low temperature. It was difficult. The cryogenic temperature of the emitter tip is the third object of the present invention.

  In addition, many of the cooling means of the gas field ionization ion source include a factor that generates mechanical vibration, which tends to be a factor of vibration of the emitter tip. The mechanical vibration reduction of the emitter tip is the fourth object of the present invention.

  These problems are problems related to the very provision of a highly stable gas field ionization ion source that can obtain a large current and a charged particle microscope equipped with the same. An object of the present invention is to provide a gas field ionization ion source that solves these problems, and a high resolution and large focal depth charged particle microscope equipped with the same.

  Also, the sample is processed by an ion beam to form a cross section, and instead of an apparatus for observing the cross section with an electron microscope, the sample is processed by an ion beam to form a cross section, and the cross section is observed with an ion microscope Intended to provide a method.

  Another object of the present invention is to provide an apparatus capable of performing sample observation with an ion microscope, sample observation with an electron microscope and elemental analysis with a single apparatus, an analysis apparatus for observing and analyzing defects and foreign substances, and an inspection apparatus.

  In the field ionization ion source, the first object of the present invention, which is both the increase in conductance during rough vacuuming and the reduction in diameter of the extraction electrode hole from the viewpoint of increasing the current of ions, is the gas molecule gas molecule ionization chamber This can be solved by providing a mechanism for varying the conductance for evacuating the vacuum chamber. In particular, the mechanism that makes the conductance variable is a mechanism that makes the conductance variable with respect to the temperature of the gas molecule ionization chamber, and this can be solved by forming a part of the members that make up the mechanism from a bimetallic alloy. Alternatively, in a charged particle microscope, there is provided a charged particle microscope characterized in that it has a mechanism for varying the conductance for evacuating the gas molecule ionization chamber when and without extracting an ion beam from the gas molecule ionization chamber. It can be solved by doing.

  In the field ionization ion source, the second object of the present invention, which is to increase the vacuum of the gas molecule ionization chamber for stabilization of ion emission, can be solved by providing a temperature control mechanism capable of heating the gas molecule ionization chamber. In particular, the problem can be solved by using a resistance heater attached to the outer wall of the gas molecule ionization chamber.

  In the field ionization ion source, the third problem of the present invention, which is the cryogenic temperature reduction of the emitter tip, can be solved by making at least one of the electrical wiring of the resistance heater switchable / switchable. In addition, a needle-like anode emitter tip can be placed on the filament and the anode emitter tip can be heated by energizing the filament, and at least one of the wires for filament energization can be connected and disconnected. It can be solved by In particular, a mechanism capable of connecting and disconnecting at least one can be solved by forming it using a bimetallic alloy. Alternatively, the problem can be solved by providing a mechanism for cooling at least one electrode of the electrostatic lens that is present in the ion extraction direction from the gas molecule ionization chamber and faces the gas molecule ionization chamber.

  In the field ionization ion source, the fourth object of the present invention, which is the mechanical vibration reduction of the emitter tip, is the refrigerant in which the coolant of the mechanism for cooling at least one electrode of the electrostatic lens is in a gas state at normal temperature and atmospheric pressure. The problem can be solved by using a gas as a solid coolant. Alternatively, the emitter tip holding mechanism can be moved relative to the gas molecule ionization chamber, and the emitter tip holding mechanism can be solved by coupling it to the cooling mechanism with a mechanically deformable member.

  According to the present invention, there is provided a gas electrolytic ionization ion source capable of achieving both an increase in conductance at the time of vacuum roughing and a reduction in diameter of the extraction electrode hole from the viewpoint of increasing the current of ions, and a large current ion beam can be obtained. Be done.

  In addition, a high vacuum of the gas molecule ionization chamber is realized, and a highly stable ion emission gas ionization ion source is provided.

  In addition, the present invention provides a gas electrolytic ionization ion source which realizes the cryogenic temperature of the emitter tip and can obtain a high current ion beam. In addition, a gas electrolytic ionizing ion source and an ion microscope capable of reducing mechanical vibration and enabling high resolution observation are provided. In addition, a gas electrolytic ionization ion source suitable for an apparatus for processing a sample with an ion beam to form a cross section and observing the cross section with an ion microscope is provided.

FIG. 1 is a schematic configuration view of an ion beam microscope of Example 1. FIG. 2 is a schematic view of the periphery of an emitter tip of the field ionization ion source of Example 1; FIG. 5 is a schematic view of wiring (at connection) of the field ionization ion source of Example 1; FIG. 2 is a schematic view of wiring (during disconnection) of the field ionization ion source of Example 1; FIG. 1 is a schematic structural view of a field ionization ion source of Example 1; FIG. 2 is a view showing a cooling mechanism of the present ion source of Example 1; FIG. 7 is a view for explaining the operation of the on-off valve (opened state) of the top plate of the gas molecule ionization chamber of the first embodiment. FIG. 7 is a view for explaining the operation of the on-off valve (closed state) of the top plate of the gas molecule ionization chamber of the first embodiment. FIG. 7 is a configuration diagram of a gas field ionization ion source of Example 3. FIG. 7 is a schematic configuration view of a gas field ionization ion source of Example 3. FIG. 16 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. 16 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. 16 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. 18 is a configuration diagram of a combined apparatus of an ion beam microscope and an ion beam processing apparatus according to a fifth embodiment. FIG. 18 is a configuration diagram of a combined apparatus of an ion beam microscope and an ion beam processing apparatus according to a fifth embodiment. FIG. 18 is a configuration diagram of a combined apparatus of an ion beam microscope and an ion beam processing apparatus according to a fifth embodiment. FIG. 18 is a configuration diagram of an ion beam microscope of Example 5.

  Hereinafter, the best mode for carrying out the present invention will be described using the drawings.

  FIG. 1 shows a schematic block diagram of the ion beam microscope of the first embodiment. This apparatus comprises a field ionization ion source 1, an ion beam irradiation system column 2, a vacuum sample chamber 3 and the like. A refrigerator 4 is connected to the field ionization ion source 1. The ion beam irradiation system column 2 stores an electrostatic condenser lens 5, a beam limiting aperture 6, a beam scanning electrode 7, an electrostatic objective lens 8 and the like. In the vacuum sample chamber 3, a sample stage 10 on which the sample 9 is placed, a secondary particle detector 11 and the like are stored. Further, an ion source evacuation pump 12 and a sample chamber evacuation pump 13 are attached. Needless to say, the inside of the ion beam irradiation system column 2 is also maintained in vacuum.

  As a device (or unit called) for controlling the present microscope, a field ionization ion source controller 91, a refrigerator controller 92, a lens controller 93, a beam limiting aperture controller 94, an ion beam scanning controller 95, a secondary An electronic detector control unit 96, a sample stage control unit 97, an evacuation pump control unit 98, a calculation processing unit 99, and the like are arranged. Here, the calculation processing device 99 includes an image display unit that displays an image generated based on a detection signal of the secondary particle detector 11 and information input by the information input unit.

  Here, the sample stage 10 has a linear movement mechanism in two orthogonal directions in the sample mounting surface, a linear movement mechanism in the direction perpendicular to the sample mounting surface, a rotation mechanism in the sample mounting surface, and rotation about the tilt axis. The tilt function is provided so that the irradiation angle of the ion beam 14 to the sample 9 can be varied by performing the control.

  First, we will discuss emitter tip fabrication. The emitter tip is a tungsten wire with a diameter of about 100 to 400 μm and an axis orientation <111>, and the tip radius of curvature is sharply formed to several tens of nm. In yet another vacuum vessel, iridium is vacuum deposited on the tip of the emitter tip. After that, when iridium atoms are moved to the tip of the emitter tip by high temperature heating, pyramids of nanometer order by iridium atoms are formed. This is called a nanopyramid. The nanopyramid tip is a single atom, but below this atom there is a layer of 3 or 6 atoms. Further below that there is a layer of ten or more atoms.

  In this embodiment, a thin wire of tungsten and iridium are used, but a thin wire of molybdenum can also be used. Although iridium is coated in this embodiment, platinum, rhenium, osmium, palladium, rhodium and the like can also be used. When helium is used as the ionization gas, it is important that the evaporation strength of the metal is larger than the electric field strength at which helium is ionized, and platinum, rhenium, osmium and iridium are preferable. In the case of hydrogen, platinum, rhenium, osmium, palladium, rhodium and iridium are preferable. In addition to the vacuum deposition method, it is possible to coat these metals by plating in a solution. In addition, the method of forming nanometer-order pyramids or nano-pyramids at the tip of the emitter tip can also be applied to other application such as electric field evaporation in vacuum or ion beam irradiation, and tungsten or molybdenum nano-pyramids can be formed . For example, in the case of using a <111> tungsten wire, it is characterized that the tip is composed of three atoms.

  FIG. 2 is a schematic view of the periphery of the emitter tip of the field ionization ion source of the present embodiment. The periphery of the emitter tip of the present electrolytic ionization ion source is constituted of an emitter tip 21, a filament 22, a filament mount 23, an extraction electrode 24, a gas supply pipe 25, and the like. Emitter tip 21 is fixed to filament 22. The filaments 22 are fixed at their ends to the support rods 26 of the filament mount.

  The extraction electrode 24 is disposed opposite to the emitter tip 21 and has a small hole 27 for extracting the ion beam 14. A cylindrical side wall 28 and a top plate 29 are connected to the extraction electrode 24 and surround the emitter tip 21. Furthermore, a cylindrical resistance heater 30 is attached around the cylindrical side wall.

  Further, an open / close valve is attached to the top plate 29. That is, the top plate has an opening 31 and a lid 32 for sealing the opening is provided. A bimetal which is deformed by temperature is used as the material of the lid, and the lid can be opened and closed by the temperature change of the bimetal. Here, the chamber surrounded by the extraction electrode, the side wall, and the top plate is called a gas molecule ionization chamber. Also, in the case of FIG. 2, the filament mount is embedded in the top plate, and the emitter tip attached to the filament mount is present in this gas molecule ionization chamber. In addition, a gas supply pipe 25 is connected to the gas molecule ionization chamber. The gas supply pipe 25 supplies helium, which is an ionized gas. Here, in the gas molecule ionization chamber, as shown in FIG. 2, the extraction electrode, the side wall, and the top plate do not have to be configured independently, but may be integrated. The present invention is not limited to a cylindrical shape, and any shape capable of introducing an ionizing gas into a space surrounding the emitter tip and applying an electric field to the emitter tip is included in the present application.

  The schematic diagram of wiring of the field ionization ion source of a present Example is shown to FIG. 3A. A wire 33 is connected to the support rod 26 of the filament mount 23, and the filament 22 can be energized by the power supply 34, and the temperature of the emitter tip 21 can be raised utilizing heat conduction from the filament. Further, a high voltage power supply 35 of ions is connected to this wire, and an acceleration voltage can be applied. As shown in FIG. 3A, a thick wire 33 made of copper and a thin wire 36 made of stainless steel are connected to the wire for energizing the filament 22. Furthermore, a cutting mechanism is attached to the thick copper wire. The schematic diagram when wiring is cut | disconnected by FIG. 3B by the cutting mechanism 37 is shown. A bimetal which is deformed by temperature is used as a part of the material of the cutting mechanism 37, and the connection / disconnection of the copper wire is switched by the temperature change of the bimetal.

  Similarly to the filament wiring described above, the thick wire 38 made of copper and the thin wire 39 made of stainless steel are connected to the wire for energizing the resistance heater, and the cutting mechanism 40 is attached to the thick wire of the copper wire. As a part of the material of this cutting mechanism function, a bimetal which is deformed by temperature is used, and the connection / disconnection of the copper wire is switched by the temperature change of the bimetal. Note that the extraction electrode 24 and the emitter tip 21 are electrically insulated, and further, since they have the same potential as one end of the resistance heater, the extraction voltage of the extraction electrode 21 with respect to the emitter tip 21 by the ion extraction power supply 41 is Can be applied. Further, even when the copper wire is cut, a drawing voltage can be applied to the drawing electrode 24 by the thin wire 39 made of stainless steel.

  Next, FIG. 4 shows a schematic structural view of the field ionization ion source of this embodiment. The emitter tip 21 is structured to be suspended from the upper flange 51. The emitter tip 21 has a movable structure so that the angle of the emitter tip 21 can be adjusted in two directions perpendicular to the horizontal and vertical directions, and the tip of the emitter tip. On the other hand, the extraction electrode 24 is fixed to the vacuum vessel. Also, the filament mount 23 is insulated by a sapphire base 52. It goes without saying that the present ion source is a vacuum vessel, but in addition to the vacuum evacuation mechanism, there is a cooling transfer mechanism from a refrigerator. The refrigerator 4 and the sapphire base 52 are connected by a cooling conductive rod 53 made of copper which is a good thermal conductor. However, since the refrigerator is fixed to the vacuum vessel, the tip of the cooling conductive rod 53 and the sapphire base 52 are connected by the deformable copper mesh wire 54. As a result, the emitter tip 21 is made movable, and the copper mesh wire 54 has the effect of reducing high frequency vibration transmission of the refrigerator. That is, an effect of providing an ion microscope capable of high resolution observation can be provided. The extraction electrode 24 has a fixed structure with respect to the vacuum vessel from the viewpoint of reducing the vibration transmission from the refrigerator, but the connection between the sapphire base 55 that supports the extraction electrode and the tip of the cooling conductor 53 of a good thermal conductor Also connected with deformable copper mesh wire 56. This produces an effect of providing an ion microscope capable of high resolution observation.

  Next, the cooling mechanism of the present ion source will be described using FIG. The feature of this device is that the refrigerator is installed in the direction perpendicular to the ion beam irradiation axis of the ion microscope. As a result, the movable mechanism of the emitter tip can be easily constructed. In the present embodiment, the pulse tube refrigerator 71 is used in the cooling mechanism. The pulse tube refrigerator is a refrigerator with relatively little vibration, and has the feature of minimizing mechanical vibration of the emitter tip. The present pulse tube refrigerator has a first cooling stage 72 which is cooled to about 70K and a second cooling stage 73 which can be cooled to 5K. The second cooling stage is covered by a radiation shield 74 connected to the first cooling stage 72. The second cooling stage is connected to the sapphire base 52 by the deformable copper mesh wire 54 through the copper cooling conductive bar 53 as described above, and finally cools the emitter tip 21. As described above, in the present ion source, mechanical vibration is reduced by connecting with the copper mesh wire 54.

  A radiation shield 74 connected to the first cooling stage of the pulse tube refrigerator is connected to the radiation shield 58 of FIG. 4 via a copper cooling conduction tube 57. The cooling conduction tube 57 is disposed up to the vicinity of the emitter tip so as to cover the cooling conduction rod 53. The radiation shield 58 surrounds the gas molecule ionization chamber including the emitter tip and reduces the heat inflow due to the heat radiation to the gas molecule ionization chamber. Further, in FIG. 4, at least one electrode of the electrostatic lens 59 which is present in the ion beam extraction direction from the gas molecule ionization chamber and faces the gas molecule ionization chamber is connected to the radiation shield. In the case of FIG. 4, the electrostatic lens is composed of three electrodes, and the electrode 60 closest to the gas molecule ionization chamber is connected to the radiation shield 58 to cool it. In the refrigerator of this embodiment, the refrigeration capacity of the first cooling stage is about 20 W, and the refrigeration capacity of the second cooling stage is about 0.5 W. In this embodiment, a radiation shield connected to the first cooling stage having a larger refrigeration capacity is provided to reduce the heat influx due to the heat radiation to the gas molecule ionization chamber and the emitter tip. This achieves the cryogenic temperature of the emitter tip and provides a gas field ionization ion source capable of obtaining an ion beam with a larger current, which in turn provides an ion microscope capable of high resolution observation.

  Next, the operation of this ion source will be described. First, the operation of the on-off valve of the top plate of the gas molecule ionization chamber will be described with reference to FIGS. 6A and 6B. After attaching the previously prepared emitter tip 21, the vacuum vessel is evacuated by the vacuum pump 12. At this time, as shown in FIG. 6A, the lid 32 of the gas molecule ionization chamber top plate is open, and the conductance of the gas molecule ionization chamber to the vacuum evacuation system is larger than that in the closed case. The effect of enabling particularly rough evacuation of the chamber in a short time is achieved.

  After evacuation, the gas electrode is outgassed by heating the lead-out electrode 24, the side wall 28, the top plate 29 and the like by the resistance heater 30 outside the side wall of the gas molecule ionization chamber. At this time, the vacuum vessel 61 is also heated by another resistance heater disposed simultaneously in the atmosphere, thereby improving the degree of vacuum of the vacuum vessel and reducing the residual gas concentration. This operation produces an effect of improving the time stability of the ion emission current. In the present embodiment, the resistance heater 30 is disposed outside the gas molecule ionization chamber. As compared with the case of being disposed inside by this, there is no degassing from the resistance heater itself, so that the gas molecule ionization chamber can be made to have a higher vacuum. Moreover, although the resistance heater was used in the present Example, you may arrange | position the lamp | ramp for heating, and you may degas the extraction electrode, a side wall, etc. FIG. According to this, since the heating can be performed without contact, the peripheral structure of the lead electrode can be simplified, and there is no need to apply a high voltage to the wiring, so that the power supply can be simplified. In addition, high temperature inert gas may be supplied from the gas supply pipe to degas the extraction electrode, the side wall, and the like. According to this, since the gas heating mechanism can be disposed at the ground potential, the structure around the extraction electrode can be simplified, and there is no need to apply a high voltage to the wiring, so that the power supply can be simplified.

  Next, the heating of the gas molecule ionization chamber and the vacuum vessel is stopped and after a sufficient time, the refrigerator is operated to cool the emitter tip, the extraction electrode, the radiation shield and the like. Then, helium, which is an ionization gas, is introduced into the gas molecule ionization chamber by the gas supply pipe 25. At this time, as shown in FIG. 6B, the lid 32 of the top plate of the gas molecule ionization chamber is in a closed state in which the bimetal alloy is deformed, and the gas molecule ionization chamber has a smaller conductance than the vacuum exhaust system. Therefore, even if a large amount of helium gas is introduced into the gas molecule ionization chamber, the degree of vacuum can be improved outside the gas molecule ionization chamber.

  Next, when a voltage is applied between the emitter tip 21 and the extraction electrode 24, a strong electric field is formed at the tip of the emitter tip. Much of the helium is pulled to the emitter tip surface with a strong electric field and reaches near the tip of the emitter tip with the strongest electric field. The helium can then be field ionized and the ion beam can be extracted through the small holes of the extraction electrode. Here, when the electric field strength is adjusted, helium ions are generated in the vicinity of one atom of the nanopyramid apex existing at the tip of the emitter tip. That is, since ions are generated in a very limited area, the current emitted from the unit area / unit solid angle can be increased. This is an important characteristic for obtaining an ion beam of fine diameter and large current on a sample.

  In particular, when iridium or the like is vapor-deposited on tungsten, the nanopyramid structure in which one atom is present at the tip can also stably generate ions. In the case of three atoms at the tip of tungsten <111>, the supplied helium gas is dispersed into three atoms. Therefore, the current emitted from the unit area / unit solid angle can be larger in the case of an ion source having a nanopyramid structure of iridium in which helium gas is concentratedly supplied to one atom. That is, the emitter tip in which iridium, platinum, rhenium, osmium or the like is deposited on tungsten produces an effect suitable for reducing the beam diameter on the sample of the ion microscope or increasing the current.

  Next, the ion beam 14 which has passed through the lens passes through the scanning deflection electrode 301 and further passes through the fine diameter hole of the aperture plate 302 to collide with the movable shutter 303. Here, when the secondary particle detector 305 detects secondary particles 304 such as secondary electrons generated by the movable shutter while scanning the ion beam and obtains a secondary particle image, the ion radiation pattern of the emitter tip is observed it can. Therefore, the emitter tip position and angle are adjusted while observing the ion radiation pattern. Also, the ion beam trajectory or aperture position can be adjusted so that an ion beam from one atom in the ion radiation pattern passes through the aperture. If the top of the pyramid consists of 3 or 6 atoms, adjust the ion beam trajectory or the aperture position so that ions emitted from the vicinity of any one atom are selected to pass through the aperture You can also Even if secondary particles such as secondary electrons emitted from the aperture plate 302 are detected by a secondary particle detector to obtain a secondary particle image, the same effect can be obtained. In particular, if a minute projection is provided on the movable shutter and the secondary particle image of this is observed, the pattern can be observed more clearly. Needless to say, after the adjustment, the shutter 303 is moved to pass the ion beam.

  Further, in the present ion source, as described above, since the degree of vacuum is high outside the gas molecule ionization chamber, the rate at which the ion beam collides with the gas in vacuum and is neutralized is small. It has the effect of being able to irradiate the sample. Further, the number of high temperature helium gas molecules colliding with the extraction electrode is reduced, the cooling temperature of the emitter tip and the extraction electrode can be lowered, and the ion beam of large current can be irradiated to the sample.

  If the nanopyramid is damaged due to an unexpected discharge phenomenon or the like, it is possible to easily regenerate the nanopyramid by heating the emitter tip for about 30 minutes (about 1000 ° C.).

  The on-off valve of this embodiment has an advantage that it can be automatically opened and closed by the cooling of the ion source cooling even if there is no other mechanical mechanism. In particular, it has a feature of being able to have a simple structure suitable for applying a high voltage.

  Also, at the time of ion beam extraction, as shown in FIG. 3B, the copper wiring of the filament and the copper wiring of the resistance heater are cut. This is performed automatically by ion source cooling, since a bimetal which is deformed by temperature is used as a part of the material of the wire cutting mechanism function. Each is given a potential by a stainless steel wire. As a result, the heat inflow from the copper wiring is eliminated, and the cooling temperature of the emitter tip and the lead-out electrode can be lowered. That is, the effects of improving the luminance of the ion source and increasing the current of the ion beam are exhibited. This has the effect of providing a gas field ionization ion source capable of obtaining a high current ion beam, and thus providing an ion microscope capable of high resolution observation.

  Next, the operation of the ion beam irradiation system will be described using FIG. The operation of the ion beam irradiation system is controlled by a command from the calculation processing unit 99. First, the ion beam 14 emitted from the emitter tip of the ion source is focused on the sample 9 on the sample stage 10 by the objective lens 8 through the condenser lens 5 and the beam limiting aperture 6. Thereby, a minute point-like beam can be obtained on the sample. In this case, the beam diameter can be reduced to 1 nm or less although the current is as small as several pA. This minute ion beam is scanned by the ion beam scanning electrode 7 and detected by the secondary particle detector 11 such as secondary electrons emitted from the sample, and the image display of the calculation processing unit 99 is carried out by intensity-modulating this. A scanning ion microscope image can be obtained on the means. That is, high resolution observation of the sample surface is realized.

  Here, the feature of the present ion source is to use ions emitted from the vicinity of one atom at the tip of the nanopyramid. That is, the region from which ions are released is narrow and the ion light source is as small as a nanometer or less. For this reason, if the ion light source is focused on the sample at the same magnification or the reduction ratio is increased to about half, it is possible to make the most of the characteristics of the ion source. The size of the light source of the conventional gallium liquid metal ion source is estimated to be about 50 nm, and in order to realize a beam diameter of 5 nm on the sample, the reduction ratio is reduced to at most 1/10. In this case, the oscillation of the emitter tip of the ion source is reduced by a factor of 10 or less on the sample. For example, even if the emitter tip vibrates by 10 nm, it is 1 nm or less on the sample, and the influence on the beam diameter of 5 nm is minor. However, in the case of the ion source according to the present embodiment, the vibration of 10 nm becomes 5 nm on the sample at a reduction ratio of 1/2, which is larger than the beam diameter. Therefore, in the conventional apparatus, consideration in this respect is not sufficient, and good observation of the sample surface has not always been realized. In the present embodiment, since measures against the vibration are sufficient, it is possible to realize high resolution observation of the sample surface which sufficiently exhibits the performance of the ion source.

  Although the lead-out electrode of the present field ionization ion source is fixed to the vacuum vessel, the emitter tip can be moved relative to the lead-out electrode by connecting the emitter tip mount with a copper mesh wire. This makes it possible to adjust the position of the lead-out electrode of the emitter tip with respect to the small hole and to adjust the axis of the optical system, and it goes without saying that it is possible to form a finer beam.

  The pulse tube refrigerator may be of either the GM type or the Stirling type. Also, in the present embodiment, a refrigerator having two cooling stages has been described, but a refrigerator having a single cooling stage may be used, and the present invention is not limited by the number of cooling stages.

  As described above, according to the present embodiment, it is possible to achieve both the increase in conductance during rough roughing vacuum and the reduction in diameter of the lead-out electrode hole from the viewpoint of increasing the current of ions, and gas electrolytic ionization can be obtained An ion source is provided.

  In addition, a high vacuum of the gas molecule ionization chamber is realized, and a highly stable ion emission gas ionization ion source is provided.

  In addition, the present invention provides a gas electrolytic ionization ion source which realizes the cryogenic temperature of the emitter and can obtain a high current ion beam. In addition, a gas electrolytic ionizing ion source and an ion microscope capable of reducing mechanical vibration and enabling high resolution observation are provided.

  In the first embodiment, a pulse tube refrigerator with relatively little vibration is used, but in order to minimize the ion beam diameter, it may not always be satisfactory. In the second embodiment, instead of the pulse tube refrigerator, a refrigerator in which a GM type refrigerator and a helium gas spot are combined is used.

  This GM type refrigerator has a first cooling stage cooled to about 50K and a second cooling stage capable of cooling to 4K. These cooling stages are covered by sealed pots. And the inside of the pot is filled with helium gas. That is, the GM type refrigerator cools the helium gas, and the helium gas cools the outer wall of the pot. By this structure, the tip of the pot is cooled to about 6 K, and the vicinity of the first cooling stage is cooled to about 70 K. In this refrigeration system, even if the GM type refrigerator vibrates, the mechanical vibration is attenuated and transmitted because helium gas is present in the middle. That is, the mechanical vibration of the helium gas spot is reduced as compared to the mechanical vibration of the GM type refrigerator. The helium gas spot is connected to the emitter tip mount via a copper wire through a copper cooling conductor as described in the first embodiment to cool the emitter tip. As described in the first embodiment, mechanical vibration is further reduced by connecting with copper mesh wire. The gas field ionization ion source using the present cooling system is characterized in that the mechanical vibration of the emitter tip can be further reduced.

  As described above, according to the present embodiment, there are provided a gas electrolytic ionization ion source and an ion microscope capable of achieving reduction of mechanical vibration and high resolution observation.

  A cooler was used in Examples 1 and 2. However, the chiller inherently generates mechanical vibration and is easy to transmit to the emitter tip. The vibration of the emitter tip also vibrates the sample irradiation point of the beam in the charged particle microscope, degrading the microscope resolution. In Example 3, solid nitrogen (the solidification temperature in vacuum is about 51 K) was used as a coolant.

  7 shows a configuration diagram of a gas field ionization ion source of the present embodiment. In the present ion source, the solid nitrogen chamber is disposed at the position where the refrigerator is disposed in Example 1. The solid nitrogen chamber 81 is a vacuum vessel, and a solid nitrogen tank 82 exists inside. The solid nitrogen tank 82 is connected with a copper transmission rod 53 as in the first embodiment. In the present ion source, the radiation shield 57 described in the first embodiment is also connected to the solid nitrogen tank 82. First, liquid nitrogen is introduced into the solid nitrogen tank 82, and then the inside of the solid nitrogen tank is evacuated from the vacuum exhaust port 83. As a result, liquid nitrogen solidifies to solid nitrogen 84. Solid nitrogen in the evacuated environment is sublimated by heat influx from the emitter tip, extraction electrode and radiation shield to cool them. In this cooling method, no vibration due to bubbling occurs when liquid nitrogen boils. That is, according to the ion source of the present embodiment, there are provided a gas electrolytic ionizing ion source and an ion microscope capable of achieving reduction of mechanical vibration and high resolution observation.

  Next, an example using solid nitrogen as the coolant for the radiation shield and liquid helium as the coolant for the emitter tip is described. FIG. 8 shows a schematic diagram of the gas field ionization ion source of this embodiment. In the present ion source, the emitter tip 21 is directly connected to the liquid helium tank 85 for cooling. The solid nitrogen 83 radiation shields around the emitter tip 21 and the gas molecule ionization chamber and the liquid helium tank 85. A copper transmission rod 57 is connected to the solid nitrogen tank 83 as described above. The method of producing solid nitrogen is the same as the method described above. In the present embodiment, solid nitrogen cools the radiation shield, but similarly vibration due to foaming does not occur. In addition, the liquid helium is separately connected by a liquid helium dure and a transfer tube (not shown), and its vibration is minimized. That is, according to the ion source of the present embodiment, there are provided a gas electrolytic ionizing ion source and an ion microscope capable of achieving reduction of mechanical vibration and high resolution observation.

  Alternatively, a refrigerator may be placed in the solid nitrogen tank to cool the solid nitrogen, and the operation of the refrigerator may be stopped only during the observation time that requires high resolution. In this case, it is possible to reduce the consumption of solid nitrogen. In addition, even if the operation of the refrigerator is stopped, the tip temperature can be kept low by the latent heat accompanying melting or evaporation of solid nitrogen. That is, according to the ion source of the present embodiment, there are provided a gas electrolytic ionizing ion source and an ion microscope capable of achieving reduction of mechanical vibration and high resolution observation. Although nitrogen is used in this embodiment, neon, oxygen, argon, methane, hydrogen and the like can also be used. In particular, when solid neon is used, it is possible to realize a low temperature suitable for increasing the current of the helium ion beam.

  FIG. 9 shows the configuration of the combined apparatus of the ion beam microscope and the electron beam microscope according to the fourth embodiment. Further, FIG. 10A is a top view of the configuration of the combined apparatus of the ion beam microscope and the electron beam microscope according to the present embodiment. FIG. 10B also shows a side view.

  The configuration and operation of the present ion beam microscope are almost the same as in the first embodiment. In this apparatus, a scanning electron microscope is attached to a vacuum sample chamber. The scanning electron microscope comprises an electron gun 101, an electron lens 103, an electron beam scanning deflector 104, an electron beam column 105 for storing them, and the like.

  In the vacuum sample chamber 3, in addition to the sample stage 10 on which the sample 9 is placed and the secondary particle detector 11, an X-ray detector 106 is disposed. The sample stage may be provided with a tilting function to make the sample surface perpendicular to the electron beam 102. In this apparatus, the helium or hydrogen ion beam and the electron beam can be irradiated at almost the same position on the sample.

  Next, the operation procedure of the scanning electron microscope will be described. The electron beam 102 emitted from the electron gun 101 is focused by the electron lens 103 and irradiated to the sample 9. At this time, the electron beam 102 is scanned by the electron beam scanning deflector 104 to irradiate the cross section of the sample, and secondary electrons emitted from the cross section of the sample are detected by the secondary particle detector 11, and the intensity is used as the brightness of the image. If converted, the sample can be observed. The electron beam irradiation position is previously adjusted to be the same as the ion beam irradiation position. First, the ion microscope image is stored in the calculation processing unit 99, and then the feature points in the stored ion microscope image are observed in the scanning electron microscope image while observing the scanning electron microscope image. The DC bias current for controlling the electron beam scanning deflector 104 may be adjusted so that the feature points are displayed at the same position. Alternatively, the DC control voltage of the scanning deflection electrode 7 of the ion microscope may be adjusted while observing the sample with the ion microscope again. Here, the electron beam irradiation position uses a scanning deflector to match the ion beam irradiation position, but a deflector for adjustment may be provided separately. In this case, since deflection control is performed to control only the DC component of the deflector, there is an effect that it is easy to manufacture a power supply having noise lower than that of the scan deflector which controls AC.

  In this way, a helium ion beam scanning secondary electron image and an electron beam scanning secondary electron image of the sample can be obtained without moving the sample stage 10. Both are displayed side by side on the image display means of the control device 99. Although both provide roughly equivalent surface information, the secondary electron yield by ion beam excitation and the secondary electron yield by electron beam excitation are different, so that different information is provided in detail, enabling more detailed analysis of the sample. .

  The characteristic of this device is that the ion beam irradiation axis 1003 of the ion microscope is approximately perpendicular to the installation plane of the device, ie, the XY plane of FIG. 10A, and the electron beam irradiation axis 1004 is the installation of the device, as shown in FIG. It was placed in the direction of inclination with respect to the surface. This relates to the features of the ion microscope described above. That is, the feature of this ion source is to use ions emitted from the vicinity of one atom at the tip of the nanopyramid. That is, the region from which ions are released is narrow and the ion light source is as small as a nanometer or less. For this reason, if the ion light source is focused on the sample at the same magnification or the reduction ratio is increased to about half, it is possible to make the most of the characteristics of the ion source.

  In order to take advantage of the high resolution observation capability of this ion microscope, the vibration of the sample, the field ionization ion source, and the vibration of the column of the ion microscope become issues.

  As a result of vibrational simulation and experimental evaluation, it was found that high resolution observation can be achieved when the ion beam irradiation axis of the ion microscope is approximately perpendicular to the installation surface of the apparatus and the sample is horizontally mounted. In particular, it was found that the tilted electron gun vibrates more than the ion source, but in the scanning electron microscope, the reduction ratio for focusing the diameter of the light source of the electron on the sample is smaller than that of the ion microscope, and the influence of the vibration of the electron gun Was found to be smaller than the ion microscope. These are new examination problems because they are ion microscopes that can obtain a resolution of 1 nm or less using an ion beam emitted from one atom at the tip of the nanopyramid as in this device, and this vibration is this problem in this example This is effective in achieving high resolution observation of the surface of the sample which sufficiently exhibits the performance of the ion source.

  In addition, if X-rays emitted from the sample are detected by the X-ray detector 106, elemental analysis of the sample surface is possible. In particular, with an ion microscope, when the accelerating voltage of ions is several tens of kV, X-rays are hardly emitted and elemental analysis is difficult. According to the present apparatus, it is possible to simultaneously perform ultra-high resolution observation with an ion beam and elemental analysis. In particular, if any two of a helium ion beam scanning secondary electron image, an electron beam scanning secondary electron image and an X-ray analysis image are displayed almost simultaneously on the image display means of the control device 99, more detailed of the sample Analysis is possible.

  Further, in this apparatus, when the vacuum sample chamber is divided into two directions, ie, the electron beam irradiation system column mounting direction and the non electron beam irradiation system column mounting direction centering on the electron beam irradiation system column mounting direction, that is, When divided, the mounting position of the X-ray detector in the vacuum sample chamber is characterized in that it is housed in the electron beam irradiation system column mounting direction, that is, on the right side of the center line 1001 in FIG. 10A. With this arrangement, the sample stage can be tilted in the direction of the electron beam column, and the electron beam can be irradiated perpendicularly to the sample for observation, enabling X-ray analysis to be possible.

  In the present embodiment, the electron beam irradiation system column and the irradiation system column of the ion microscope are arranged so that the helium or hydrogen ion beam and the electron beam can irradiate approximately the same position on the sample. If the beam irradiation axis and the electron beam irradiation axis are arranged on the sample at different positions without substantially crossing each other, each objective lens can be close to the sample because there is no mechanical interference with each other, and the resolution of each microscope The effect is that it can be improved.

  In addition, the feature of this device is that the refrigerator is installed in the horizontal direction perpendicular to the ion beam irradiation axis of the ion microscope, and the direction is the center of projection of the irradiation axis direction 1004 of the electron microscope on the XY plane of FIG. It is characterized in that it is a direction different from the right side with respect to the central axis 1001 on the axis 1002. That is, the refrigerator is not disposed on the right side of the central axis 1001 on the central axis 1002 in FIG. 10A. It is most preferable to arrange on the left side in the opposite direction as shown in FIG. 10A. This is also the result of vibration simulation and experimental evaluation taking into consideration that the vibration of the refrigerator affects the resolution of the scanning electron microscope, but the refrigerator has an irradiation axis direction 1004 of the scanning electron microscope shown in FIG. 10A. It has been found that when the refrigerator is disposed on the central axis 1002 projected on the XY plane and to the right of the central axis 1001, the observation resolution of the scanning electron microscope is degraded due to the influence of the vibration.

  As described above, according to the present embodiment, an apparatus capable of sample observation with an ion microscope, sample observation with an electron microscope and elemental analysis with one apparatus, an apparatus analyzer suitable for observing and analyzing defects and foreign substances, And an inspection device is provided.

  FIG. 11 shows the configuration of a combined apparatus of an ion beam microscope and an ion beam processing apparatus according to the fifth embodiment. FIG. 12A is a top view of the configuration of the combined apparatus of the ion beam microscope and the ion beam processing apparatus according to the present embodiment. FIG. 10B also shows a side view.

  The configuration and operation of the present ion beam microscope are almost the same as in the first embodiment. The arrangement of the refrigerator 4 is characterized, and as shown in FIG. 12B, the refrigerator 4 was installed in a lateral direction perpendicular to the ion beam irradiation axis 1003 of the ion microscope. Next, an ion beam processing apparatus combined with an ion beam microscope includes a liquid metal ion source 201 for emitting gallium, a condenser lens 202, an objective lens 203, an ion beam scanning deflector 204, a stencil mask 205, and a processing for storing them. It comprises an ion beam irradiation system column 206 and the like. A vacuum sample chamber 3 is disposed below the ion microscope column and the processing ion beam irradiation system column, and a first sample stage 10 for placing a sample 9 in the vacuum sample chamber, a secondary particle detector 11, a depot gas source 207 and the like are stored. In this apparatus, a probe 208 for transporting a sample piece extracted from the sample on the first sample stage using ion beam processing, a manipulator 209 for driving the probe, and a second sample on which a minute sample piece is placed A stage 210 is provided. In this embodiment, a gallium ion beam irradiation system column and a helium or hydrogen ion beam irradiation system column are arranged so that the helium or hydrogen ion beam and the gallium ion beam can irradiate approximately the same position on the sample. Needless to say, the inside of the ion beam irradiation system column 206 is also maintained in vacuum.

  Here, the second sample stage 210 has a tilt function capable of changing the irradiation angle of the ion beam to the sample piece by rotating around the tilt axis. Further, since the second sample stage 210 is disposed on the first sample stay 10, linear movement in two orthogonal directions in the first sample mounting surface, a straight line in the direction perpendicular to the sample mounting surface The movement and the in-plane rotation of the sample mounting surface are made possible by moving and rotating the first sample stage 10.

  Next, the operation of this device will be described. First, a gallium ion beam 211 is extracted from the liquid metal ion source 201. Then, this ion beam is focused by the condenser lens 202 in the vicinity of the center of the objective lens. The ion beam then passes through a stencil mask 205 having rectangular holes. The objective lens 203 is controlled under the condition that the stencil mask 205 is projected onto the sample. In this way, a rectangular shaped ion beam is irradiated onto the sample. When the shaped ion beam continues to be irradiated, a rectangular hole is formed in the sample.

  In this device, the observation function with an ion microscope is also used to observe the cross section of a sample defect or foreign substance, or to observe the cross section of a thin film sample for an electron microscope to grasp the processing end point.

  In this apparatus, it is possible to extract a minute sample from the sample by an ion beam processing apparatus, fix it to a probe, and place it on the second stage by using a manipulator. This can be observed by an ion microscope. That is, it is possible to observe the structure inside the sample in the same apparatus with high resolution as compared with the conventional observation with the electron beam.

  In particular, in the conventional electron beam scanning microscope, there is a problem that the trajectory of the gallium ion beam is separated into two because the magnetic field of the electron lens mass separates the isotope of gallium. As a result, in the conventional FIB-SEM apparatus, processing of gallium can not be performed with high accuracy, or there is a problem that SIM images by gallium ion beams become double. In the ion microscope of the present embodiment, an electrostatic lens is used instead of a magnetic field lens, and such a problem is solved, and it is possible to achieve high-precision processing and high-resolution image observation.

  In the above embodiments, the ion microscope scans the ion beam to detect secondary electrons. However, ions transmitted through the thin film sample may be detected. In addition, if secondary electrons generated on the back of the thin film are detected, the surface of the back of the sample can be observed.

  The feature of this device is that the ion beam irradiation axis 1003 of the ion microscope is substantially perpendicular to the installation plane of the device, ie, the XY plane of FIG. 12A as shown in FIG. Are arranged in the inclined direction with respect to the installation surface of the device. In order to make use of the high resolution features of the present ion microscope, this is the problem of the vibration of the sample, the field ion source, and the vibration of the ion beam irradiation system column of the ion microscope. That is, the feature of this ion source is to use ions emitted from the vicinity of one atom at the tip of the nanopyramid. That is, the region from which ions are released is narrow and the ion light source is as small as a nanometer or less. For this reason, if the ion light source is focused on the sample at the same magnification or the reduction ratio is increased to about half, it is possible to make the most of the characteristics of the ion source.

  In order to take advantage of the high resolution observation capability of this ion microscope, the vibration of the sample, the field ionization ion source, and the vibration of the column of the ion microscope become issues.

  As a result of vibrational simulation and experimental evaluation, it was found that high resolution observation can be achieved when the ion beam irradiation axis of the ion microscope is approximately perpendicular to the installation surface of the apparatus and the sample is horizontally mounted. In particular, it was found that the tilted gallium liquid metal ion source vibrates more than the field ionization ion source, but as described above, in the gallium liquid metal ion source, the reduction ratio for focusing the light source diameter of the ions on the sample is It is found that it is smaller than the ion microscope and the influence of the vibration of the gallium liquid metal ion source is smaller than that of the ion microscope. These are new problems to be considered because they are ion microscopes that can achieve resolution of 1 nm or less using an ion beam emitted from one atom at the tip of the nanopyramid as in the present apparatus. Since the measures are sufficient, it is possible to realize high resolution observation of the surface of the sample which fully demonstrates the performance of the ion source.

  Also, the feature of this device is that the refrigerator is installed in the horizontal direction perpendicular to the ion beam irradiation axis of the ion microscope, and the direction projects the irradiation axis direction 1005 of the gallium focused ion beam onto the XY plane of FIG. 12A. It is characterized in that it is a direction different from the left side of the central axis 1001 on the central axis 1002. That is, the refrigerator is not disposed on the left side of the central axis 1001 on the central axis 1002 in FIG. 12A. It is most preferable to arrange on the right side which is the opposite direction as shown in FIG. 12A. This is also the result of vibration simulation and experimental evaluation taking into consideration that the vibration of the refrigerator affects the resolution of the gallium focused ion beam processing apparatus, but the refrigerator has a gallium focused ion beam irradiation direction When the refrigerator is disposed on the central axis 1002 projected 1005 on the XY plane of FIG. 12A on the left side of the central axis 1001, it is found that the gallium focused ion beam processing accuracy performance is deteriorated due to the influence of the vibration.

  Although a gallium liquid metal ion source is used in this embodiment, it may be a plasma ion source for generating an inert gas such as argon or xenon or a gas ion such as oxygen or nitrogen. In this case, there is an effect that the sample is not contaminated with gallium.

  In addition, in an ion beam processing apparatus in which holes are formed by irradiating a gas ion beam to a silicon wafer and extracting a small sample, the gas ion beam is irradiated to fill holes while introducing a deposition gas; It is possible to flatten the hole surface by measuring the three-dimensional shape of the surface formed by using the ion beam of the ion microscope and controlling the inert gas ion beam based on the measurement result I understand. That is, even if the processed silicon wafer is returned to the process of the semiconductor device, there is an effect that the manufacturing is not adversely affected. In this case, the ion beam is not necessarily the ion beam of the ion microscope, and the same effect can be obtained with the electron beam of the electron microscope. The method of measuring the three-dimensional shape can be measured by the parallax of two images obtained by tilting the sample or tilting the ion beam or the electron beam and irradiating the sample. Alternatively, the difference in focus depending on the sample height may be used. A method of controlling the ion beam so as to flatten the obtained three-dimensional shape of the sample may be set appropriately for the irradiation position and the irradiation time for each place in scan control. For example, the ion beam may be irradiated for a longer time to a place lower than flat. As described above, according to the present invention, there is provided an ion beam processing apparatus which can fill holes processed by ion beam flat and is suitable for returning a processed wafer to a manufacturing process line.

  In addition, it has been found that the sound of the compressor 1100 which sends helium to the refrigerator 4 vibrates the field ionization ion source and degrades its resolution. For this reason, as shown in FIG. 13, an apparatus cover 1101 is provided which spatially separates the compressor of the refrigerator and the field ionization ion source. As a result, the sound of the compressor of the refrigerator is shielded to further reduce the influence of vibration, and a gas electrolytic ionization ion source and an ion microscope capable of high resolution observation are provided.

  Although the turbo molecular pump is used as a vacuum pump for evacuating the field ionization ion source in the above embodiments, if the non-evaporable getter pump and the ion pump are made of a noble pump, the influence of vibration is further reduced and high It has been found that a gas electrolytic ionization ion source and an ion microscope capable of resolution observation are provided. Here, the non-evaporable getter pump is a vacuum pump configured using an alloy that adsorbs gas when activated by heating. When helium is used as the ionization gas of the field ionization ion source, although a relatively large amount of helium is present in the vacuum vessel, the non-evaporable getter pump hardly exhausts helium so that the getter surface may be saturated with adsorbed gas molecules This has the effect that the operating time of the non-evaporable getter pump can be extended. This is an effect produced by combining a helium ion microscope and a non-evaporable getter pump. In addition, the impurity gas in the vacuum chamber is reduced, so that the ion emission current is stabilized. However, although the non-evaporable getter pump exhausts residual gas other than helium at a high exhaust rate, helium alone remains in the ion source and the degree of vacuum deteriorates, so that the ion source does not operate. Therefore, a vacuum is maintained by combining an ion pump or a noble pump having a high exhaust gas exhaust rate. If only the ion pump or the noble pump is used, a large pump is required to increase the pumping speed, and the structure becomes complicated. This time, a compact and low cost ion source could be realized by combining the non-evaporable getter pump and the ion pump or the noble pump. In the past, the consideration of mechanical vibration was insufficient and the performance of the ion microscope was not sufficiently obtained, but the present invention provides a gas electrolytic ionizing ion source and an ion microscope capable of achieving reduction of mechanical vibration and high resolution observation. Be done.

  As described above, according to the present invention, it is possible to achieve both of the increase in conductance during rough roughing vacuum and the reduction in diameter of the lead-out electrode hole from the viewpoint of increasing the current of ions, and a gas electrolytic ionized ion can be obtained Source is provided.

  Further, when the non-evaporable getter pump is disposed in the middle of the helium gas supply pipe, the impurity gas is reduced in the supplied gas, thereby providing a gas electrolytic ionization ion source and an ion microscope in which the ion emission current is stabilized. In addition, a high vacuum of the gas molecule ionization chamber is realized, and a highly stable ion emission gas ionization ion source is provided. In particular, it was found that when the non-evaporable getter material is built in the ionization chamber, the ionization chamber becomes high vacuum and the ion beam current is stabilized. In addition, it was found that the compact and safe device could be realized by adsorbing hydrogen to the non-evaporable getter material and using the released hydrogen as the ionized gas by heating the non-evaporable getter material.

  In addition, the present invention provides a gas electrolytic ionization ion source which realizes the cryogenic temperature of the emitter and can obtain a high current ion beam. In addition, a gas electrolytic ionizing ion source and an ion microscope capable of reducing mechanical vibration and enabling high resolution observation are provided.

  Further, an apparatus and a cross-sectional observation method suitable for forming a cross section by processing with an ion beam and observing the cross section with an ion microscope at high resolution are provided.

  In addition, if a mass spectrometer is provided in the sample chamber, elemental analysis of the sample is facilitated, and an apparatus capable of sample observation with an ion microscope and elemental analysis with a single device is provided.

  As described above, according to the present invention, an apparatus capable of sample observation with an ion microscope, sample observation with an electron microscope, and elemental analysis with a single device, observation and analysis of defects and foreign matter, etc., and measurement of structural dimensions on the sample An analysis device, an ion beam length measuring device or an inspection device suitable for the present invention is provided.

  Also, in an inspection apparatus that irradiates a sample in a semiconductor device manufacturing process with ions emitted from a gas electrolytic ionization ion source to detect particles emitted from the sample and measure dimensions on the sample, the ion beam is applied to the sample It was found that when the energy is less than 1 kV, damage to the sample can be reduced, and returning the measured wafer to the manufacturing process will not adversely affect the electrical characteristics of the device. In particular, when applying a positive bias voltage to the sample such that the acceleration voltage of the ion is 2 kV positive and the applied voltage to the sample is 1.5 kV positive, measurement is performed with the energy of the ion beam to the sample less than 1 kV. It is possible to increase the current and to perform accurate measurement. Further, as compared with the conventional measurement using an electron beam, the depth of focus of the obtained image is deep, so that it is possible to perform the measurement with high accuracy. In addition, particularly when a hydrogen ion beam is used, there is an effect that the amount of scraping the surface of the sample is small and accurate measurement can be performed. As described above, according to the present invention, an ion beam length measuring device or inspection device suitable for measuring a structural dimension on a sample is provided.

DESCRIPTION OF SYMBOLS 1 ... field ionizing ion source 2 ... ion beam irradiation system column 3 ... vacuum sample room 4 ... refrigerator 5 ... condenser lens 6 ... beam limiting aperture 7 ... beam scanning electrode 8 ... objective lens 9 ... sample 10 ... sample stage 11 ... 2 Next particle detector 12 ... ion source evacuation pump 13 ... sample chamber evacuation pump 14 ... ion beam 15 ... gas molecule ionization chamber 21 ... emitter tip 22 ... filament 23 ... filament mount 24 ... extraction electrode 25 ... gas supply piping 26: Support rod 27 for filament mount: Small hole 28: Side wall 29: Top plate 30: Resistance heater 31: Opening 32: Lid 33: Electric wire 34: Power supply 35: High voltage power supply 36: Stainless steel thin wire 37: Cutting mechanism 38: Copper thick wire 39: Stainless steel thin wire 40: Cutting mechanism 51: Upper flange 52: Sapphire base 5 ... Cooling conduction rod 54 ... Copper mesh wire 55 ... Sapphire base 56 ... Copper mesh wire 60 ... Electrode 61 ... Vacuum vessel 71 ... Pulse tube refrigerator 72 ... First cooling stage 73 ... Second cooling stage 74 ... Radiation shield 81 ... Solid Nitrogen chamber 82: solid nitrogen tank 83: vacuum exhaust port 84: solid nitrogen 85: liquid helium tank 92: refrigerator control device 93: lens control device 94: beam limiting aperture control device 95: ion beam scanning control device 96: secondary Electronic detector control device 97 Sample stage control device 98 Pump control device for vacuum exhaust 99 Calculation processing device 101 Electron gun 103 Electronic lens 104 Electron beam scanning deflector 105 Electron beam irradiation system column 106 X-ray Detector 201 Liquid metal ion source 202 Condenser lens 203 Objective lens 204 Ion beam scanning Aimator 205 ... stencil mask 206 ... ion beam irradiation system column for processing 207 ... deposition gas source 208 ... probe 209 ... manipulator 210 ... second sample stage 211 ... gallium ion beam 301 ... scanning deflection electrode 302 ... aperture plate 303 ... movable shutter 304 secondary particle 305 secondary particle detector.

Claims (10)

The vacuum vessel, a vacuum evacuation mechanism having a non-evaporable getter pump for evacuating the vacuum vessel, a gas molecule ionization chamber installed in the vacuum vessel and containing an emitter tip, and a cooling mechanism for the emitter tip A gas field ionization ion source which supplies gas near the tip of the emitter tip and ionizes the gas by an electric field at the tip of the emitter tip;
A lens system for focusing an ion beam extracted from the emitter tip;
A sample chamber containing a sample;
And a secondary particle detector for detecting secondary particles emitted from the sample by the irradiation of the ion beam.
An extraction electrode for achieving differential pumping between the gas molecule ionization chamber and the vacuum vessel
An ion beam device characterized by A vacuum vessel, an evacuation mechanism for evacuating the vacuum vessel, a gas molecule ionization chamber installed in the vacuum vessel and including an emitter tip, and a cooling mechanism for the emitter tip, the vicinity of the tip of the emitter tip A gas electric field ionizing ion source for supplying a gas to the electrode and ionizing the gas with an electric field at the tip of the emitter tip;
A lens system for focusing an ion beam extracted from the emitter tip;
A sample chamber containing a sample;
A secondary particle detector for detecting secondary particles emitted from the sample by irradiation of the ion beam;
A gas supply pipe connected to the gas molecule ionization chamber;
In the gas supply pipe, a non-evaporable getter pump is disposed in the middle of the pipe,
An extraction electrode for achieving differential pumping between the gas molecule ionization chamber and the vacuum vessel
An ion beam device characterized by A vacuum vessel, an evacuation mechanism for evacuating the vacuum vessel, a gas molecule ionization chamber installed in the vacuum vessel and including an emitter tip, and a cooling mechanism for the emitter tip, the vicinity of the tip of the emitter tip A gas electric field ionizing ion source for supplying a gas to the electrode and ionizing the gas with an electric field at the tip of the emitter tip;
A lens system for focusing an ion beam extracted from the emitter tip;
A sample chamber containing a sample;
And a secondary particle detector for detecting secondary particles emitted from the sample by the irradiation of the ion beam.
Forming the gas molecule ionization chamber into a structure including a non-evaporable getter material;
An extraction electrode for achieving differential pumping between the gas molecule ionization chamber and the vacuum vessel
An ion beam device characterized by Method of operating an ion beam device, comprising
The ion beam device
A vacuum vessel, an evacuation mechanism for evacuating the vacuum vessel, a gas molecule ionization chamber installed in the vacuum vessel and including an emitter tip, and a cooling mechanism for the emitter tip, the vicinity of the tip of the emitter tip A gas electric field ionizing ion source for supplying a gas to the electrode and ionizing the gas with an electric field at the tip of the emitter tip;
A lens system for focusing an ion beam extracted from the emitter tip;
A sample chamber containing a sample;
And a secondary particle detector for detecting secondary particles emitted from the sample by the irradiation of the ion beam.
Differential evacuation is realized via an extraction electrode placed between the gas molecule ionization chamber and the vacuum vessel,
The method of operating an ion beam apparatus, wherein the vacuum evacuation mechanism exhausts the vacuum vessel at least including a non-evaporable getter pump. The ion beam apparatus according to claim 1, wherein
An ion beam apparatus characterized in that the cooling mechanism uses solid nitrogen. The ion beam apparatus according to claim 1, wherein
An electron beam microscope is combined, and the irradiation axis of the ion beam is substantially perpendicular to the installation surface of the ion beam apparatus, and the electron beam irradiation axis is disposed in the inclination direction on the installation surface of the ion beam apparatus. Ion beam device. A method of operating an ion beam device according to claim 4,
A method of operating an ion beam apparatus comprising applying a positive bias voltage to the sample. A method of operating an ion beam device according to claim 4,
A method of operating an ion beam apparatus, comprising measuring the sample size while setting the energy of the ion beam to the sample to less than 1 keV. A method of operating an ion beam device according to claim 4,
The method of operating an ion beam apparatus, wherein the ion beam is a hydrogen ion beam. A method of operating an ion beam device according to claim 4,
An operation method of an ion beam apparatus, which observes a sample with a resolution of 1 nm or less.

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