JP6696019B2 - Ion beam device and method of operating the same - Google Patents

Description

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

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

  Since the secondary electron excitation region due to the penetration of hydrogen or helium ions into the sample surface is localized on the sample surface compared to electron irradiation, the SIM image is more sensitive to polar sample surface information than the SEM image. Is expected. Further, from the viewpoint of a microscope, since ions are heavier than electrons, the diffraction effect can be neglected in the beam focusing, and an image with a very deep depth of focus can be obtained.

  Further, by irradiating the sample with an electron or ion beam and detecting the electrons or ions that have passed through the sample, it is possible to obtain information that reflects the internal structure of the sample. These are called transmission electron microscopes or transmission ion microscopes. In particular, when the sample is irradiated with a light-mass ion species such as hydrogen or helium, the proportion of light that penetrates the sample increases, which is suitable for observation.

  The gas electrolytic ionization ion source is expected to have a fine beam because of its narrow ion energy width and small ion generation source size, and is a suitable ion source for the above scanning ion microscope and transmission ion microscope. Patent Document 1 discloses that the ion source characteristics are improved by using an emitter tip having a minute protrusion at the tip of the emitter tip of the gas electrolytic ionization ion source. Further, as an example of manufacturing a minute protruding portion at the tip of the emitter tip, Non-Patent Document 1 discloses that a second metal different from the emitter tip material is used for manufacturing.

  Further, 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 arranged so as to surround an ion generating part and the like. In this document, a heating means for performing degassing treatment on the atmosphere side of the vacuum container of the gas electrolytic ionization ion source, a cooling container for cooling the vacuum container on the outside of the heating device, 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 forced discharge treatment between the outer wall of the ion source and the emitter tip, so-called conditioning. A gas electrolytic ionization ion source is disclosed which can prevent a discharge between the emitter tip and the extraction electrode after treatment. In addition, there is an example in which a sample is irradiated with an ion beam and particles that compose the sample are ejected from the sample by a sputtering action of ions. The sample can also be finely processed. At this time, it is preferable to use a focused ion beam device (hereinafter, FIB) using a liquid metal ion source (hereinafter, LMIS). In recent years, the FIB-SEM device, which is a combination of SEM and focused ion beam, has also been used. In this FIB-SEM device, the cross section can be observed by SEM by irradiating the FIB and forming a square hole at a desired position.

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

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

Published Patent Publication No. S58-85242 Published Patent Publication No. Sho 63-216249 Published Patent Publication No. 1-2221847 Published Patent Publication No. 2002-150990 Published International Patent Publication WO99 / 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 with 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 emission 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. This introduced gas is differentially exhausted through the holes of the extraction electrode. For vacuum evacuation of this gas molecule ionization chamber, it is desirable that the hole diameter be large. However, when the extraction electrode has a large hole, when the ion material gas pressure is increased to ~ 1 Pa or more, the vacuum degree outside the gas molecule ionization chamber deteriorates and the ion beam collides with the neutral gas and is neutralized. Therefore, the ionic current is reduced. In addition, when the number of gas molecules outside the gas molecule ionization chamber increases, the gas molecules that collide with the radiation shield or the vacuum chamber wall, which have a higher temperature than the gas molecule ionization chamber, collide with the gas molecule ionization chamber, causing the gas molecule ionization chamber to collide. However, there is a problem that the temperature rises and the ion current decreases. In the gas field ionization ion source, it is a first object of the present invention to increase the conductance at the time of rough vacuuming and to reduce the diameter of the extraction electrode hole from the viewpoint of increasing the ion current.

  Further, in the gas field ionization ion source, when the impurity tip is adsorbed on the emitter tip, the ion may be released from that location, and the ion release from the tip of the emitter tip becomes unstable. That is, the second object of the present invention is to reduce impurities in the periphery of the emitter tip as much as possible, that is, to make the gas molecule ionization chamber highly vacuum.

  In addition, in order to obtain a large ion current in the gas field ionization ion source, it is important to increase the gas molecule density near the tip. The gas molecule density per unit pressure is inversely proportional to the temperature of the gas, and it is important to cool the gas including the emitter tip. Since a gas field ionization ion source generally applies a high voltage to the emitter tip, it is necessary to join it to a high temperature region with a good conductor or to face a high temperature ion beam lens, so it is possible to freeze the emitter tip to an extremely low temperature. It was difficult. The third issue of the present invention is to make the emitter tip extremely cold.

  In addition, many cooling means of the gas field ionization ion source include a factor that causes mechanical vibration, which is likely to cause a vibration of the emitter tip. Reducing the mechanical vibration of the emitter tip is the fourth object of the present invention.

  These issues are related to the 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 charged particle microscope with a high resolution and a large depth of focus equipped with the same.

  In addition, instead of an apparatus that processes a sample with an ion beam to form a cross section and observes the cross section with an electron microscope, an apparatus that processes the sample with the ion beam to form a cross section and then observes the cross section with an ion microscope and cross section observation The purpose is to provide a method.

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

  In the field ionization ion source, both the increase in conductance during vacuum roughing and the reduction in the diameter of the extraction electrode hole from the viewpoint of increasing the current of the ions are compatible with each other. The first object of the present invention is to provide a gas molecule gas molecule ionization chamber. This can be solved by providing a mechanism for varying the conductance of evacuating the. 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 constituting the mechanism with a bimetal alloy. Alternatively, in the charged particle microscope, a charged particle microscope characterized by including a mechanism for varying the conductance of evacuating the gas molecule ionization chamber when the ion beam is extracted from the gas molecule ionization chamber and when the ion beam is not extracted. It can be solved by doing.

  In the field ionization ion source, the second object of the present invention, which is a high vacuum of the gas molecule ionization chamber for stabilizing the ion emission, can be solved by providing a temperature adjusting mechanism capable of heating the gas molecule ionization chamber. In particular, this 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 extremely low temperature of the emitter tip, can be solved by providing a mechanism capable of connecting / disconnecting at least one of the electric wires of the resistance heater. In addition, a needle-shaped anode emitter tip is installed on the filament, and the anode emitter tip can be heated by energizing the filament, and at least one of the filament energizing wires can be connected / disconnected. Can be solved with. In particular, it can be solved by forming a mechanism capable of connecting / disconnecting at least one of them by using a bimetal alloy. Alternatively, it can be solved by providing a mechanism for cooling at least one electrode of the electrostatic lens existing in the ion extraction direction from the gas molecule ionization chamber and facing the gas molecule ionization chamber.

  A fourth object of the present invention, which is a mechanical vibration reduction of the emitter tip in the field ionization ion source, is that the coolant of the mechanism for cooling at least one electrode of the electrostatic lens is a gas state at room temperature and atmospheric pressure. The problem can be solved by using gas as a solid state coolant. Alternatively, it can be solved by making the emitter tip holding mechanism movable with respect to the gas molecule ionization chamber and connecting the emitter tip holding mechanism to the cooling mechanism by 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 rough vacuuming and a reduction in the diameter of an extraction electrode hole from the viewpoint of a large ion current, and a large current ion beam can be obtained. To be done.

  Further, a high vacuum of the gas molecule ionization chamber is realized, and a gas electrolytic ionization ion source capable of highly stable ion release is provided.

  In addition, a gas electrolytic ionization ion source that can realize a cryogenic emitter tip and obtain a high-current ion beam is provided. In addition, a gas electrolytic ionization ion source and ion microscope capable of reducing mechanical vibration and enabling high-resolution observation are provided. Further, 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.

1 is a schematic configuration diagram of an ion beam microscope of Example 1. FIG. 3 is a schematic diagram of the vicinity of an emitter tip of the field ionization ion source of Example 1. FIG. 3 is a schematic diagram of wiring (when connected) of the field ionization ion source of Example 1. FIG. 3 is a schematic diagram of wiring (when disconnected) of the field ionization ion source of Example 1. FIG. 2 is a schematic structural diagram of a field ionization ion source of Example 1. FIG. 3 is a diagram showing a cooling mechanism of the present ion source of Example 1. FIG. FIG. 6 is a diagram for explaining the operation of the on-off valve (open state) of the gas molecule ionization chamber top plate of the first embodiment. FIG. 5 is a diagram illustrating an operation of an opening / closing valve (closed state) of the top plate of the gas molecule ionization chamber of Example 1. 6 is a configuration diagram of a gas field ionization ion source of Example 3. FIG. 6 is a schematic configuration diagram of a gas field ionization ion source of Example 3. FIG. 7 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. 7 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. 7 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. It is a block diagram of the compound apparatus of the ion beam microscope of Example 5, and an ion beam processing apparatus. It is a block diagram of the compound apparatus of the ion beam microscope of Example 5, and an ion beam processing apparatus. It is a block diagram of the compound apparatus of the ion beam microscope of Example 5, and an ion beam processing apparatus. 9 is a configuration diagram of an ion beam microscope of Example 5. FIG.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration 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 a sample 9 is placed, a secondary particle detector 11 and the like are stored. Further, an ion source vacuum exhaust pump 12 and a sample chamber vacuum exhaust 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 a unit) for controlling this 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 controller An electronic detector control device 96, a sample stage control device 97, a vacuum exhaust pump control device 98, a calculation processing device 99 and the like are arranged. Here, the calculation processing device 99 includes an image display unit for displaying an image generated based on the detection signal of the secondary particle detector 11 and information input by the information input means.

  Here, the sample stage 10 has a linear movement mechanism in two orthogonal directions in the sample mounting surface, a linear movement mechanism in a direction perpendicular to the sample mounting surface, a sample mounting in-plane rotation mechanism, and a rotation around an inclination axis. The sample stage control device 97 is provided with a tilting function capable of varying the irradiation angle of the ion beam 14 onto the sample 9 by means of the instruction.

  First, the fabrication of the emitter tip will be described. The emitter tip is a tungsten wire with a diameter of about 100 to 400 μm and an axial orientation of <111>, and the tip radius of curvature is sharply formed to several tens nm. In another vacuum container, iridium is vacuum-deposited on the tip of the emitter tip. After that, when the iridium atom is moved to the tip of the emitter tip by heating at high temperature, a pyramid of nanometer order is formed by the iridium atom. This is called a nanopyramid. The tip of the nanopyramid is one atom, but below this atom is a layer of three or six atoms. Further below that is a layer of 10 or more atoms.

  Although the thin tungsten wire and iridium are used in this embodiment, a thin molybdenum wire may be used. In addition, although iridium is coated in this embodiment, platinum, rhenium, osmium, palladium, rhodium, or the like can be used instead. When helium is used as the ionized 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 suitable. In the case of hydrogen, platinum, rhenium, osmium, palladium, rhodium and iridium are suitable. In addition to the vacuum deposition method, plating with a solution may be used to coat these metals. The method of forming a nanometer-order pyramid, that is, a nanopyramid, at the tip of the emitter tip can also be applied by applying electric field evaporation in vacuum or ion beam irradiation, and a nanopyramid of tungsten or molybdenum can be formed. .. For example, when <111> tungsten wire is used, the tip is composed of three atoms.

  FIG. 2 shows a schematic diagram around the emitter tip of the field ionization ion source of this embodiment. The periphery of the emitter tip of this electrolytic ionization ion source is composed of an emitter tip 21, a filament 22, a filament mount 23, an extraction electrode 24, a gas supply pipe 25, and the like. The emitter tip 21 is fixed to the filament 22. Both ends of the filament 22 are fixed to support rods 26 of a filament mount.

  The extraction electrode 24 is arranged so as to face the emitter tip 21, and has a small hole 27 through which the ion beam 14 is extracted. A cylindrical side wall 28 and a top plate 29 are connected to the extraction electrode 24 and surround the emitter tip 21. Further, a cylindrical resistance heater 30 is attached around the cylindrical side wall.

  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 closing the opening. Bimetal, which deforms with temperature, is used as the material of this lid, and the lid can be opened and closed by changing the temperature of the bimetal. Here, the room surrounded by the extraction electrode, the side wall, and the top plate is called a gas molecule ionization room. Further, in the case of FIG. 2, the filament mount is embedded in the top plate, and the emitter tip attached to the filament mount exists inside this gas molecule ionization chamber. 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, the extraction electrode, the side wall, and the top plate do not have to be independently configured as shown in FIG. 2, and may be integrated. Further, the present invention is not limited to a cylindrical shape, and any shape that can introduce an ionized gas into the space surrounding the emitter tip and can apply an electric field to the emitter tip is included in the present application.

  FIG. 3A shows a schematic diagram of the wiring of the field ionization ion source of this example. An electric wire 33 is connected to the support rod 26 of the filament mount 23, and the filament 22 can be energized by a power source 34, and the temperature of the emitter tip 21 can be raised by utilizing heat conduction from the filament. Further, an ion high voltage power source 35 is connected to this electric wire, and it is possible to apply an acceleration voltage. 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 wiring for energizing the filament 22. Further, a cutting mechanism is attached to the thick copper wire. FIG. 3B shows a schematic diagram when the wiring is cut by the cutting mechanism 37. Bimetal, which is deformed by temperature, is used as a part of the material of the cutting mechanism 37, and connection / disconnection of the copper wire is switched depending on the temperature change of the bimetal.

  A thick wire 38 made of copper and a thin wire 39 made of stainless steel are connected to the wiring for energizing the resistance heater in the same manner as the above filament wiring, and a cutting mechanism 40 is attached to the thick wire of the copper wire. Bimetal, which deforms depending on temperature, is used as a part of the material for this disconnection mechanism function, and connection / disconnection of the copper wire can be switched depending on the temperature change of the bimetal. Note that the extraction electrode 24 and the emitter tip 21 are electrically insulated from each other and have the same potential as one end of the resistance heater. Therefore, the extraction voltage is applied to the extraction electrode by the ion extraction power source 41 with respect to the emitter tip 21. Can be applied. Further, even when the copper wire is cut, the extraction voltage can be applied to the extraction electrode 24 by the thin wire 39 made of stainless steel.

  Next, FIG. 4 shows a schematic structural diagram of the field ionization ion source of this embodiment. The emitter tip 21 is hung from the upper flange 51, and has a movable structure so that the emitter tip 21 can be adjusted in two horizontal right and left directions and the vertical direction, and the angle of the tip of the emitter tip 21 can be adjusted. On the other hand, the extraction electrode 24 is fixed to the vacuum container. The filament mount 23 is insulated by the sapphire base 52. Needless to say, this ion source is a vacuum container, but in addition to the vacuum exhaust mechanism, there is a cooling transmission mechanism from the refrigerator. The refrigerator 4 and the sapphire base 52 are connected by a copper cooling conductive rod 53 which is a good heat conductor. However, since the refrigerator is fixed to the vacuum container, the tip of the cooling conducting rod 53 and the sapphire base 52 are connected by a deformable copper mesh wire 54. As a result, the emitter tip 21 is made movable, and the vibration transmission of the refrigerator at a high frequency is reduced by the copper wire 54. That is, it is possible to provide an ion microscope capable of high-resolution observation. From the viewpoint of reducing the vibration transmission from the refrigerator, the extraction electrode 24 has a fixed structure with respect to the vacuum container, but the sapphire base 55 supporting the extraction electrode is connected to the tip of the cooling conductive rod 53 of a good heat conductor. Are also connected by a deformable copper wire 56. This has the effect of providing an ion microscope capable of high-resolution observation.

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

  The 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 the copper cooling conduction tube 57. The cooling conduction pipe 57 is arranged near 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 heat inflow to the gas molecule ionization chamber due to heat radiation. Further, in FIG. 4, at least one electrode of the electrostatic lens 59 existing in the ion beam extraction direction from the gas molecule ionization chamber and facing 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 refrigerating capacity of the first cooling stage is about 20 W and the refrigerating capacity of the second cooling stage is about 0.5 W. In the present embodiment, a radiation shield connected to the first cooling stage having a larger refrigerating capacity is provided to reduce heat inflow due to heat radiation to the gas molecule ionization chamber and the emitter tip. As a result, an extremely low temperature of the emitter tip is realized, a gas field ionization ion source capable of obtaining an ion beam with a larger current is provided, and further, an ion microscope capable of high resolution observation is provided.

  Next, the operation of this ion source will be described. First, the operation of the opening / closing valve of the top plate of the gas molecule ionization chamber will be described with reference to FIGS. 6A and 6B. After mounting the emitter tip 21 prepared in advance, the vacuum container is evacuated by the vacuum pump 12. At this time, as shown in FIG. 6A, the lid 32 of the top plate of the gas molecule ionization chamber is open, and the conductance of the gas molecule ionization chamber with respect to the vacuum exhaust system is larger than that when it is closed. The effect is that the chamber can be roughly evacuated in a short time.

  After evacuation, the extraction electrode 24, the side wall 28, and the top plate 29 are degassed by heating with a resistance heater 30 outside the side wall of the gas molecule ionization chamber. At this time, the vacuum container 61 is also simultaneously heated by another resistance heater arranged in the atmosphere to improve the vacuum degree of the vacuum container and reduce the residual gas concentration. This operation has the effect of improving the time stability of the ion emission current. In this embodiment, the resistance heater 30 is arranged outside the gas molecule ionization chamber. As a result, there is no degassing from the resistance heater itself, as compared with the case where the resistance heater itself is placed, and the gas molecule ionization chamber can be made to have a higher vacuum. Further, although the resistance heater is used in this embodiment, a heating lamp may be arranged to degas the extraction electrode, the side wall and the like. According to this, since the heating can be performed in a non-contact manner, the structure around the extraction electrode can be simplified, and it is not necessary to apply a high voltage to the wiring. Further, a 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, the gas heating mechanism can be arranged at the ground potential, so that 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 have a simple structure.

  Next, after the heating of the gas molecule ionization chamber and the vacuum container is stopped and a sufficient time has passed, the refrigerator is operated to cool the emitter tip, the extraction electrode, the radiation shield and the like. Then, helium, which is an ionized gas, is introduced into the gas molecule ionization chamber through 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 closed due to the deformation of the bimetal alloy, and the gas molecule ionization chamber has a small conductance with respect to 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. Most of the helium is pulled by the emitter tip surface by the strong electric field and reaches the vicinity of the tip of the emitter tip with the strongest electric field. Then, helium is ionized by electric field, and the ion beam can be extracted through the small hole of the extraction electrode. Here, when the electric field strength is adjusted, helium ions are generated in the vicinity of one atom at the apex of the nanopyramid existing at the tip of the emitter tip. That is, since ions are generated in a very limited area, the current emitted from a unit area or unit solid angle can be increased. This is an important characteristic for obtaining an ion beam with a small diameter and large current on the sample.

  Particularly, when iridium or the like is deposited on tungsten, the nanopyramid structure having one atom 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 the three atoms. Therefore, an ion source having an iridium nanopyramid structure, in which helium gas is concentrated and supplied to one atom, can generate a larger current from a unit area or unit solid angle. That is, an emitter tip in which iridium, platinum, rhenium, osmium, or the like is deposited on tungsten is suitable for reducing the beam diameter on the sample of the ion microscope and increasing the current.

  Next, the ion beam 14 that has passed through the lens passes through the scanning deflection electrode 301, further passes through a hole having a minute diameter of the aperture plate 302, and collides with the movable shutter 303. Here, when the secondary particle detector 305 detects the secondary particles 304 such as secondary electrons generated by the movable shutter while scanning the ion beam to obtain a secondary particle image, the ion emission pattern of the emitter tip is observed. it can. Therefore, the emitter tip position and angle are adjusted while observing the ion emission pattern. Further, the ion beam trajectory or the aperture position can be adjusted so that the ion beam from one atom passes through the aperture in the ion emission pattern. When the tip of the pyramid is composed of 3 or 6 atoms, the ion beam trajectory or aperture position is adjusted so that ions emitted from the vicinity of any one atom are selected and pass through the aperture. You can also do it. 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 fine projections are provided on the movable shutter and the secondary particle image of the projections is observed, the pattern can be observed more clearly. Needless to say, the shutter 303 is moved to pass the ion beam after the main adjustment.

  Further, in the present ion source, as described above, since the degree of vacuum is high outside the gas molecule ionization chamber, the ion beam collides with the gas in the vacuum and is less likely to be neutralized. The sample can be irradiated. In addition, 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 sample can be irradiated with a high-current ion beam.

  If the nanopyramid is damaged due to an unexpected discharge phenomenon, the nanopyramid can be easily regenerated by heating the emitter tip for about 30 minutes (about 1000 ° C).

  The on-off valve of the present embodiment has an advantage that it can be automatically opened and closed by cooling the ion source without any other mechanical mechanism. In particular, it has a feature that it can have a simple structure suitable for applying a high voltage.

  Further, when the ion beam is extracted, the copper wiring of the filament and the copper wiring of the resistance heater are cut as shown in FIG. 3B. This is done automatically by cooling the ion source because bimetal, which deforms with temperature, is used as part of the material for the wiring cutting mechanism function. Note that each is given a potential by stainless wiring. As a result, the heat inflow from the copper wiring is eliminated, and the cooling temperature of the emitter tip and the extraction electrode can be lowered. That is, the effects of improving the brightness of the ion source and increasing the current of the ion beam are achieved. As a result, a gas electric field ionization ion source capable of obtaining a high-current ion beam is provided, and further, an ion microscope capable of high-resolution observation is provided.

  Next, the operation of the ion beam irradiation system will be described with reference to FIG. The operation of the ion beam irradiation system is controlled by a command from the calculation processing device 99. First, the ion beam 14 emitted from the tip of 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. As a result, a minute point beam can be obtained on the sample. In this case, the current is as small as several pA, but the beam diameter can be made as small as 1 nm or less. The fine ion beam is scanned by the ion beam scanning electrode 7 to detect it by the secondary particle detector 11 such as secondary electrons emitted from the sample, and the brightness thereof is modulated to display an image on the calculation processing device 99. 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 this ion source is to use ions emitted from the vicinity of one atom at the tip of the nanopyramid. That is, the area from which ions are emitted is narrow, and the ion light source is as small as a nanometer or less. Therefore, if the ion source is focused on the sample at the same magnification or the reduction rate is increased to about 1/2, the characteristics of the ion source can be maximized. The size of the light source of a conventional gallium liquid metal ion source is estimated to be about 50 nm, and in order to achieve a beam diameter of 5 nm on the sample, the reduction rate should be reduced to less than 1/10 at most. In this case, the vibration of the emitter tip of the ion source is reduced to less than 1/10 on the sample. For example, even if the emitter tip oscillates 10 nm, it is less than 1 nm on the sample, and the effect on the beam diameter of 5 nm is slight. However, in the ion source according to the present embodiment, the vibration of 10 nm becomes a vibration of 5 nm on the sample at a reduction ratio of ½, which is larger than the beam diameter. Therefore, the conventional device did not pay sufficient attention to this point, and it was not always possible to achieve good observation of the sample surface. In this embodiment, since the countermeasure against this vibration is sufficient, there is an effect that high-resolution observation of the sample surface can be realized, which shows the performance of the ion source sufficiently.

  Although the extraction electrode of the present field ionization ion source is fixed to the vacuum container, the emitter tip is movable with respect to the extraction electrode by connecting the emitter tip mount with a copper mesh wire. As a result, it goes without saying that the position adjustment of the extraction electrode of the emitter tip with respect to the small hole and the axis adjustment with respect to the optical system can be performed, and a finer beam can be formed.

  The pulse tube refrigerator may be either a GM type or a Stirling type. Further, although the refrigerator having two cooling stages has been described in the present embodiment, 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 at the time of rough vacuuming and the reduction in the diameter of the extraction electrode hole from the viewpoint of increasing the current of ions, and to obtain a large current ion beam by gas electrolytic ionization. An ion source is provided.

  Further, a high vacuum of the gas molecule ionization chamber is realized, and a gas electrolytic ionization ion source capable of highly stable ion release is provided.

  In addition, a gas electrolytic ionization ion source that can achieve a cryogenic temperature of the emitter and obtain a high-current ion beam is provided. In addition, a gas electrolytic ionization ion source and ion microscope capable of reducing mechanical vibration and enabling high-resolution observation are provided.

  In Example 1, a pulse tube refrigerator with comparatively little vibration was used, but it may not always be satisfactory to minimize the beam diameter of the ion beam. In Example 2, instead of the pulse tube refrigerator, a refrigerator in which a GM type refrigerator and a helium gas spot were combined was used.

  This GM 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 a sealed pot. And 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. With this structure, the tip of the pot is cooled to about 6K, and the vicinity of the first cooling stage is cooled to about 70K. In this refrigeration system, even if the GM type refrigerator vibrates, mechanical vibration is attenuated and transmitted because helium gas exists in the middle. That is, the mechanical vibration of the helium gas spot is reduced as compared with the mechanical vibration of the GM type refrigerator. As described in the first embodiment, the helium gas spot is connected to the emitter tip mount by a copper mesh wire via the cooling conducting rod made of copper, and cools the emitter tip. As described in the first embodiment, the mechanical vibration is further reduced by connecting with the copper mesh wire. The gas field ionization ion source using this cooling system has a feature that the mechanical vibration of the emitter tip can be further reduced.

  As described above, according to this embodiment, a gas electrolytic ionization ion source and an ion microscope capable of reducing mechanical vibration and enabling high-resolution observation are provided.

  In Examples 1 and 2, a cooler was used. However, the cooler essentially generates mechanical vibration and is easily transmitted to the emitter tip. 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 (solidification temperature in vacuum is about 51 K) was used as the coolant.

  7 is a block diagram of the gas field ionization ion source of the present embodiment. In this ion source, the solid nitrogen chamber is arranged at the place where the refrigerator is arranged in the first embodiment. The solid nitrogen chamber 81 is a vacuum container, and a solid nitrogen tank 82 exists inside. A copper transmission rod 53 is connected to the solid nitrogen tank 82 as in the first embodiment. In this ion source, the radiation shield 57 described in the first embodiment is also connected to the solid nitrogen tank 82. Liquid nitrogen is first introduced into the solid nitrogen tank 82, and then the solid nitrogen tank is evacuated from the vacuum exhaust port 83. As a result, the liquid nitrogen is solidified into the solid nitrogen 84. The solid nitrogen in the vacuum exhaust environment is sublimated by the inflow of heat from the emitter tip, the extraction electrode and the radiation shield, and cools them. In this cooling method, vibration due to foaming when liquid nitrogen boils does not occur. That is, according to the ion source of the present embodiment, a gas electrolytic ionization ion source and an ion microscope capable of realizing mechanical vibration reduction and high resolution observation are provided.

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

  Further, 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 an observation time period requiring 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 due to the latent heat of solid nitrogen melting or vaporizing. That is, according to the ion source of the present embodiment, a gas electrolytic ionization ion source and an ion microscope capable of realizing mechanical vibration reduction and high resolution observation are provided. In this embodiment, nitrogen is used, but neon, oxygen, argon, methane, hydrogen, etc. can also be used. In particular, when solid neon is used, there is an effect that 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 shows a top view of the configuration of the combined apparatus of the ion beam microscope and the electron beam microscope according to this embodiment. A side view is also shown in FIG. 10B.

  The configuration and operation of this ion beam microscope are almost the same as in the first embodiment. In this device, a scanning electron microscope is attached to the vacuum sample chamber. The scanning electron microscope is composed of 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, an X-ray detector 106 is arranged in addition to the sample stage 10 on which the sample 9 is placed and the secondary particle detector 11. The sample stage has a tilting function, and the sample surface can be perpendicular to the electron beam 102. In this device, the helium or hydrogen ion beam and the electron beam can irradiate 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 on the sample 9. At this time, the sample cross section is irradiated with the electron beam 102 being scanned by the electron beam scanning deflector 104, secondary electrons emitted from the sample cross section are detected by the secondary particle detector 11, and the intensity thereof is used as the brightness of the image. After conversion, the sample can be observed. The electron beam irradiation position is adjusted in advance so as to be the same as the ion beam irradiation position. This is because the ion microscope image is first stored in the calculation processing device 99, and then the characteristic 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 characteristic 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 the scanning deflector to match the ion beam irradiation position, but a deflector for adjustment may be provided separately. In this case, since the deflection control is performed to control only the direct current component of the deflector, there is an effect that it is easy to manufacture a power source having lower noise than the power source of the scanning deflector that controls the alternating current.

  By doing so, 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. Both provide approximately equivalent surface information, but because the secondary electron yield due to ion beam excitation and the secondary electron yield due to electron beam excitation are different, they provide different information in detail, enabling more detailed analysis of the sample. ..

  10B, the ion beam irradiation axis 1003 of the ion microscope is substantially perpendicular to the installation surface of the apparatus, that is, the XY plane of FIG. 10A, and the electron beam irradiation axis 1004 is the installation of the apparatus. That is, it is arranged in the direction of inclination with respect to the plane. This relates to the features of the ion microscope described above. That is, the feature of this ion source is to use the ions emitted from the vicinity of one atom at the tip of the nanopyramid. That is, the area from which ions are emitted is narrow, and the ion light source is as small as a nanometer or less. Therefore, the characteristics of the ion source can be maximized by focusing the ion light source on the sample at the same magnification or by increasing the reduction rate to about half.

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

  As a result of vibration simulation and experimental evaluation, it was found that high-resolution observation is possible when the ion beam irradiation axis of the ion microscope is placed substantially perpendicular to the installation surface of the device and the sample is placed horizontally. In particular, it was found that the tilted electron gun vibrates more than the ion source, but the scanning electron microscope has a smaller reduction rate for focusing the electron source diameter on the sample than the ion microscope, and the influence of the vibration of the electron gun is large. Was smaller than the ion microscope. Since these are ion microscopes that use an ion beam emitted from one atom at the tip of the nanopyramid as in this device and can obtain a resolution of 1 nm or less, they are new research subjects, and this oscillation is caused in this example. Since the countermeasures against the above are sufficient, it is possible to realize high-resolution observation of the sample surface, which shows the performance of the ion source sufficiently.

  Further, if the 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, X-rays were hardly emitted when the accelerating voltage of ions was several tens of kV, and elemental analysis was difficult. With this device, it is possible to simultaneously perform ultra-high resolution observation by an ion beam and elemental analysis. In particular, if any two of the helium ion beam scanning secondary electron image, the electron beam scanning secondary electron image, and the X-ray analysis image are displayed side by side on the image display means of the controller 99 at the same time, a more detailed sample is displayed. Analysis is possible.

  Further, in the present apparatus, when the vacuum sample chamber is divided into two, with the electron beam irradiation system column mounting direction as the center and in the electron beam irradiation system column mounting direction and in the other direction, that is, in FIG. When divided, the feature is that the mounting position of the X-ray detector in the vacuum sample chamber is set within the mounting direction of the electron beam irradiation system column, that is, on the right side of the center line 1001 in FIG. 10A. With such an arrangement, there is an effect that X-ray analysis becomes possible even when the sample stage is tilted in the direction of the electron beam column and the sample is irradiated with the electron beam perpendicularly and observed.

  In this embodiment, the electron beam irradiation system column and the ion microscope irradiation system column are arranged so that the helium or hydrogen ion beam and the electron beam can irradiate the same position on the sample. If the beam irradiation axis and the electron beam irradiation axis are arranged at positions apart from each other without substantially intersecting with each other on the sample, the objective lenses can be brought close to the sample because mechanical interference with each other is eliminated, and the resolution of each microscope can be increased. There is an effect that it can be improved.

  Further, the feature of this device is that the refrigerator is installed in a horizontal direction perpendicular to the ion beam irradiation axis of the ion microscope, and the direction is the center of the irradiation axis direction 1004 of the electron microscope projected on the XY plane of FIG. 10A. It is characterized in that the direction on the axis 1002 is different from the right side of the central axis 1001. That is, no refrigerator is arranged on the central axis 1002 of FIG. 10A on the right side of the central axis 1001. Most preferably, it is located on the left side, which is the opposite direction, as shown in FIG. 10A. This is also the result obtained as a result of vibration simulation and experimental evaluation in consideration of the fact that the vibration of the refrigerator affects the resolution of the scanning electron microscope. This is because it has been found that when a refrigerator is placed on the right side of the central axis 1002 projected on the XY plane of the central axis 1002, the observation resolution of the scanning electron microscope deteriorates due to the influence of vibration.

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

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

  The configuration and operation of this ion beam microscope are almost the same as in the first embodiment. It should be noted that the refrigerator 4 is characterized by its arrangement. As shown in FIG. 12B, the refrigerator 4 was installed in a 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 is provided with 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 is composed of an ion beam irradiation system column 206 and the like. A vacuum sample chamber 3 is arranged below the ion microscope column and the processing ion beam irradiation system column. Inside the vacuum sample chamber, a first sample stage 10 for mounting a sample 9 and a secondary particle detector are provided. 11, a deposit gas source 207 and the like are stored. Further, 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. The stage 210 is provided. In this embodiment, the gallium ion beam irradiation system column and the 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 almost 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 arranged on the first sample stay 10, linear movement in two orthogonal directions within the first sample mounting surface and straight line in a direction perpendicular to the sample mounting surface are performed. The movement and the rotation on the sample mounting surface can be performed by moving and rotating the first sample stage 10.

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

  In this equipment, the observation function by the ion microscope is also used for observing the cross section of defects and foreign matters of the sample, and observing the cross section of the thin film sample for electron microscope to grasp the processing end point.

  In this device, it becomes possible to extract a minute sample from the sample by the ion beam processing device, fix it on the probe, and place it on the second stage by making full use of the manipulator. This can be observed with an ion microscope. That is, there is an effect that the structure inside the sample can be observed with higher resolution in the same apparatus as compared with the conventional observation using the electron beam.

  In particular, in the conventional electron beam scanning microscope, the magnetic field of the electron lens separates the isotopes of gallium by mass, so that there is a problem that the orbits of the gallium ion beam are separated into two. As a result, the conventional FIB-SEM system has a problem that gallium cannot be processed with high precision, or the SIM image by the gallium ion beam becomes double. Since the ion microscope of this embodiment uses the electrostatic type lens instead of the magnetic field lens, it has an effect of solving such a problem and enabling high-precision processing and high-resolution image observation.

  Although the ion microscope scans the ion beam to detect the secondary electrons in the above embodiments, the ions that have passed through the thin film sample may be detected. Also, by detecting the secondary electrons generated on the back surface of the thin film, the surface of the back surface of the sample can be observed.

  The apparatus is characterized in that the ion beam irradiation axis 1003 of the ion microscope is substantially perpendicular to the installation surface of the apparatus, that is, the XY plane of FIG. 12A, as shown in FIG. 12B, and the ion beam irradiation axis 1005 of the gallium focused ion beam is 1005. Is arranged in an inclined direction with respect to the installation surface of the device. In order to take advantage of the high resolution features of this ion microscope, vibration of the sample, field ionization ion source, and ion beam irradiation system column of the ion microscope pose problems. That is, the feature of this ion source is to use the ions emitted from the vicinity of one atom at the tip of the nanopyramid. That is, the area from which ions are emitted is narrow, and the ion light source is as small as a nanometer or less. Therefore, the characteristics of the ion source can be maximized by focusing the ion light source on the sample at the same magnification or by increasing the reduction rate to about half.

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

  As a result of vibration simulation and experimental evaluation, it was found that high-resolution observation is possible when the ion beam irradiation axis of the ion microscope is placed substantially perpendicular to the installation surface of the device and the sample is placed horizontally. In particular, it was found that the tilted gallium liquid metal ion source has a larger vibration than the field ionization ion source. As described above, the gallium liquid metal ion source has a reduction ratio for focusing the light source diameter of the ions on the sample. It was found that the effect of vibration of the gallium liquid metal ion source is smaller than that of the ion microscope and smaller than that of the ion microscope. Since these are ion microscopes that use an ion beam emitted from one atom at the tip of the nanopyramid as in the present device and can obtain a resolution of 1 nm or less, they are new research subjects. Since sufficient countermeasures are taken, there is an effect that high-resolution observation of the sample surface can be realized while exhibiting the performance of the ion source.

  The feature of this device is that the refrigerator is installed in a horizontal direction perpendicular to the ion beam irradiation axis of the ion microscope, and that 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 the direction is different from the left side of the central axis 1001 on the central axis 1002. That is, no refrigerator is arranged on the central axis 1002 of FIG. 12A on the left side of the central axis 1001. Most preferably, it is located on the right side, which is the opposite direction, as shown in FIG. 12A. This is also the result obtained by vibration simulation and experimental evaluation considering that the vibration of the refrigerator affects the resolution of the gallium focused ion beam processing equipment. This is because it was found that when a refrigerator is placed on the left side of the central axis 1001 on the central axis 1002 where 1005 is projected on the XY plane of FIG. 12A, the gallium focused ion beam processing accuracy performance deteriorates due to the influence of vibration.

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

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

  It was also found that the sound of the compressor 1100 that sends helium to the refrigerator 4 vibrates the field ionization ion source and deteriorates its resolution. Therefore, as shown in FIG. 13, a device cover 1101 for spatially separating the compressor of the refrigerator and the field ionization ion source is provided. As a result, the gas of the compressor of the refrigerator is shielded, the influence of vibration is further reduced, and a gas electrolytic ionization ion source and ion microscope capable of high-resolution observation are provided.

  In addition, although the turbo molecular pump is used as a vacuum pump for evacuating the field ionization ion source in the above-described embodiments, if a non-evaporable getter pump and an ion pump or a noble pump are used, the influence of vibration is further reduced and the It was 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 made of an alloy that adsorbs gas when activated by heating. When helium is used as the ionization gas of the field ionization ion source, helium is present in a relatively large amount in the vacuum container, but the non-evaporable getter pump hardly exhausts helium, so the getter surface may be saturated with adsorbed gas molecules. There is an effect that the operation time of the non-evaporable getter pump can be lengthened. This is an effect produced by combining a helium ion microscope and a non-evaporable getter pump. Further, the ion emission current is stabilized by reducing the impurity gas in the vacuum container. However, the non-evaporable getter pump exhausts residual gas other than helium at a high pumping speed, but with this alone, helium remains in the ion source, the degree of vacuum deteriorates, and the ion source does not operate. Therefore, the vacuum is maintained by combining an ion pump or a noble pump with a high exhaust rate of the inert gas. If only an ion pump or a noble pump is used, a large pump is required to increase the pumping speed, which complicates the structure. This time, we have realized a compact and low-cost ion source by combining a non-evaporable getter pump, an ion pump, and a noble pump. Conventionally, 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 ionization ion source and an ion microscope capable of reducing mechanical vibration and enabling high-resolution observation. To be done.

  As described above, according to the present invention, both the increase in conductance during rough vacuuming and the reduction in the diameter of the extraction electrode hole from the viewpoint of increasing the current of ions can be achieved at the same time, and a gas electrolytic ionized ion that can obtain a large current ion beam can be obtained. Source is provided.

  Further, when the non-evaporable getter pump is arranged in the middle of the helium gas supply pipe, the impurity gas is reduced in the gas to be supplied, so that a gas electrolytic ionization ion source and an ion microscope in which the ion emission current is stabilized are provided. Further, a high vacuum of the gas molecule ionization chamber is realized, and a gas electrolytic ionization ion source capable of highly stable ion release is provided. In particular, it was found that a structure in which the non-evaporable getter material is contained in the ionization chamber has a high vacuum in the ionization chamber and the ion beam current is stabilized. It was also found that a compact and safe device can be realized by adsorbing hydrogen to the non-evaporable getter material, heating the non-evaporable getter material, and using the released hydrogen as the ionized gas.

  In addition, a gas electrolytic ionization ion source that can achieve a cryogenic temperature of the emitter and obtain a high-current ion beam is provided. In addition, a gas electrolytic ionization ion source and ion microscope capable of reducing mechanical vibration and enabling high-resolution observation are provided.

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

  Further, if the sample chamber is equipped with a mass spectrometer, the elemental analysis of the sample is facilitated, and a device capable of observing the sample with an ion microscope and elemental analysis is provided by one device.

  As described above, according to the present invention, the sample observation by the ion microscope, the sample observation by the electron microscope, and the device capable of elemental analysis by one device, the defect and the foreign matter are observed and analyzed, and the structural dimension on the sample is measured. An analyzer, an ion beam length measuring device, or an inspection device suitable for the above are provided.

  Further, in an inspection apparatus for irradiating 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, It was found that when the energy is less than 1 kV, damage to the sample can be reduced, and even if the wafer after measurement is returned to the manufacturing process, the electrical characteristics of the device are not adversely affected. In particular, when measuring the ion beam energy below 1 kV by applying a positive bias voltage to the sample such that the accelerating voltage of the ion is positive 2 kV and the voltage applied to the sample is positive 1.5 kV, the ion irradiation is performed. This has an effect that the current can be increased and accurate measurement can be performed. Further, as compared with the conventional measurement using the electron beam, the depth of focus of the obtained image is deep, so that the measurement can be performed with high accuracy. In addition, the use of the hydrogen ion beam has an effect that the amount of scraping the sample surface is small and accurate measurement can be performed. As described above, according to the present invention, there is provided an ion beam length measuring apparatus or an inspection apparatus suitable for measuring a structural dimension on a sample.

DESCRIPTION OF SYMBOLS 1 ... Electric field ionization ion source 2 ... Ion beam irradiation system column 3 ... Vacuum sample chamber 4 ... Refrigerator 5 ... Condenser lens 6 ... Beam limiting aperture 7 ... Beam scanning electrode 8 ... Objective lens 9 ... Sample 10 ... Sample stage 11 ... Secondary particle detector 12 ... Ion source vacuum pump 13 ... Sample chamber vacuum pump 14 ... Ion beam 15 ... Gas molecule ionization chamber 21 ... Emitter tip 22 ... Filament 23 ... Filament mount 24 ... Extraction electrode 25 ... Gas supply pipe 26 ... Filament mount support rod 27 ... Small hole 28 ... Side wall 29 ... Top plate 30 ... Resistance heater 31 ... Opening 32 ... Lid 33 ... Electric wire 34 ... Power source 35 ... High voltage power source 36 ... Stainless wire 37 ... Cutting mechanism 38 ... Copper thick wire 39 ... Stainless thin wire 40 ... Cutting mechanism 51 ... Upper flange 52 ... Sapphire base 53 ... Cooling conductive rod 54 ... Copper mesh wire 55 ... Sapphire base 56 ... Copper mesh wire 60 ... Electrode 61 ... Vacuum container 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 electron detector control device 97 ... Sample stage control device 98 ... Evacuation pump control device 99 ... Calculation processing device 101 ... Electron gun 103 ... Electron 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 deflector 205 ... Stencil Mask 206 ... Ion beam irradiation system column 207 for processing Deposition gas source 208 ... Probe 209 ... Manipulator 210 ... Second sample stage 211 ... Gallium ion beam 301 ... Scan deflection electrode 302 ... Aperture plate 303 ... Movable shutter 304 ... Secondary particles 305 ... Secondary particle detector.

Claims (8)

A vacuum container, a vacuum exhaust mechanism for exhausting the vacuum container, a gas molecule ionization chamber installed in the vacuum container and including an emitter tip, and a cooling mechanism for the emitter tip, and the vicinity of the tip of the emitter tip. A gas field ionizing ion source for supplying a gas to, and ionizing the gas with an electric field at the tip of the emitter tip,
A lens system for focusing the ion beam extracted from the emitter tip,
A sample chamber containing a sample,
A secondary particle detector that detects secondary particles emitted from the sample by irradiation of the ion beam,
A gas supply pipe connected to the gas molecule ionization chamber,
The gas supply pipe is arranged non-evaporable getter pump in the middle pipe,
An ion beam device characterized in that The ion beam device according to claim 1,
An ion beam device, wherein the cooling mechanism uses solid nitrogen. The ion beam device according to claim 1,
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 arranged in an inclined direction on the installation surface of the ion beam apparatus. Ion beam device. A method of operating an ion beam device, comprising:
The ion beam device,
A vacuum container, a vacuum exhaust mechanism for exhausting the vacuum container, a gas molecule ionization chamber installed in the vacuum container and including an emitter tip, and a cooling mechanism for the emitter tip, near the tip of the emitter tip. A gas field ionizing ion source for supplying a gas to, and ionizing the gas with an electric field at the tip of the emitter tip,
A lens system for focusing the 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,
The gas supply pipe has a non-evaporable getter pump arranged in the middle of the pipe,
The method of operating an ion beam apparatus, wherein the vacuum exhaust mechanism includes at least a non-evaporable getter pump to exhaust the vacuum container. A method of operating an ion beam device according to claim 4, wherein
A method for operating an ion beam device, comprising applying a positive bias voltage to the sample. A method of operating an ion beam device according to claim 4, wherein
A method for operating an ion beam apparatus, which comprises measuring the sample size with the energy of the ion beam for the sample being less than 1 keV. A method of operating an ion beam device according to claim 4, wherein
A method for operating an ion beam device, wherein the ion beam is a hydrogen ion beam. A method of operating an ion beam device according to claim 4, wherein
A method for operating an ion beam device, which comprises observing a sample with a resolution of 1 nm or less.

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