JP5969586B2 - Ion beam equipment - Google Patents

Description

  The present invention relates to a gas field ion source for generating ions and a charged particle microscope for observing the surface and 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 using an ion beam microscope and an electron microscope.

  By irradiating the sample while scanning electrons and detecting secondary charged particles emitted from the sample, the structure of the sample surface can be observed. This is called a scanning electron microscope (hereinafter abbreviated as SEM). On the other hand, the structure of the sample surface can also be observed by irradiating the sample while scanning with an ion beam and detecting secondary charged particles emitted from the sample. This is called a scanning ion microscope (hereinafter abbreviated as SIM). In particular, if the sample is irradiated with a light ion species such as hydrogen or helium, the sputtering effect becomes relatively small, which is suitable for observing the sample.

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

  Moreover, if the sample is irradiated with an electron or ion beam and the electrons or ions transmitted through the sample are detected, information reflecting the structure inside the sample can be obtained. 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 or helium, the rate of transmission through the sample increases, which is suitable for observation.

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

  Non-Patent Document 2 discloses a scanning ion microscope equipped with a gas electrolytic ion source that emits 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 unit and the like. This document includes a heating means for degassing the atmosphere side of the vacuum vessel of the gas ionization ion source, and a cooling vessel for cooling the vacuum vessel outside the heating means, and the amount of liquid nitrogen used is reduced. 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 a forced discharge process between the outer wall of the ion source and the emitter tip, so-called conditioning. A gas 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 in which the sample is irradiated with an ion beam, and a process using an action in which particles constituting the sample are ejected from the sample by an ion sputtering action is used. The sample can be finely processed. At this time, it is preferable to use a focused ion beam device (hereinafter referred to as FIB) using a liquid metal ion source (hereinafter referred to as LMIS). In recent years, the combined FIB-SEM device of SEM and focused ion beam has come to be 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 location.

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

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

Published Patent Publication No. 58-85242 Published Patent Publication No. Sho 63-216249 Published Patent Publication No. 1-221847 Published Patent Publication 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

If an ion beam with a large current density is obtained on an ion microscope using a field ion source, 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 angle current density of the field ion source, the better. In order to increase the ion radiation angle current density, the ion material gas pressure 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. It is desirable that the pore diameter be large for vacuum roughing of the gas molecule ionization chamber. However, when the hole of the extraction electrode is large, when the ion material gas pressure is increased to 1 Pa or more, the degree of vacuum outside the gas molecule ionization chamber deteriorates and the ion beam collides with the neutral gas to neutralize it. Therefore, the ionic current is reduced. In addition, when the number of gas molecules outside the gas molecule ionization chamber increases, the gas molecule ionization chamber collides with the gas molecule ionization chamber because the gas molecules that collide with the radiation shield or the vacuum vessel wall at a higher temperature than the gas molecule ionization chamber. There was a problem that the ion current decreased due to an increase in temperature. In the gas field ion source, it is a first object of the present invention to achieve both increase in conductance during vacuum roughing and reduction in diameter of the extraction electrode hole from the viewpoint of increasing the ion current.

  In addition, when impurity molecules are adsorbed on the emitter tip in the gas field ion source, ions may be emitted from the emitter tip, leading to a problem that ion emission from the tip of the emitter tip becomes unstable. That is, the second object of the present invention is to reduce 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 ion current in the gas field ion source, it is important to increase the gas molecule density near the tip. The density of gas molecules per unit pressure is inversely proportional to the gas temperature, and it is important to cool the gas including the emitter tip. A gas field ion source generally applies a high voltage to the emitter tip and must be joined to a high temperature region with a good conductor or face a high temperature ion beam lens, so the emitter tip can be frozen to a very low temperature. It was difficult. The cryogenic temperature of the emitter tip is the third problem of the present invention.

  In addition, many of the means for cooling the gas field ion source include a factor that generates mechanical vibrations, which tends to cause emitter tip vibrations. Reduction of the mechanical vibration of the emitter tip is the fourth problem of the present invention.

  These issues are related to the provision of a highly stable gas field ionization ion source and a charged particle microscope equipped with such a gas current ionization ion source. It is an object of the present invention to provide a gas field ion source that solves these problems, and a charged particle microscope having a high resolution and a large depth of focus equipped with the ion source.

  Also, instead of an apparatus that forms a cross section by processing a sample with an ion beam and observes the cross section with an electron microscope, an apparatus and a cross section observation that form the cross section by processing with an ion beam and observe the cross section with an ion microscope It aims to provide a method.

  It is another object of the present invention to provide a device capable of observing samples with an ion microscope, observing samples with an electron microscope, and elemental analysis with a single device, an analyzing device for observing and analyzing defects and foreign matters, and an inspection device.

In a field ion source, the first problem of the present invention, which is to achieve both the increase in conductance during rough evacuation and the reduction in diameter of the extraction electrode hole from the viewpoint of increasing the current of ions, is a gas molecule gas molecule ionization chamber. This can be solved by providing a mechanism for changing the conductance for evacuating the gas. 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 from a bimetal alloy. Alternatively, in the charged particle microscope, a charged particle microscope comprising a mechanism for changing a conductance for 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. This can be solved.

  In the field ionization ion source, the second problem of the present invention, which is to increase the vacuum of the gas molecule ionization chamber in order to stabilize ion emission, can be solved by providing a temperature control 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 ion source, the third problem of the present invention, which is to reduce the temperature of the emitter tip, can be solved by providing a mechanism capable of switching between connection and disconnection of at least one of the electric wires of the resistance heater. Also, the anode emitter tip can be heated by installing a needle-like anode emitter tip on the filament and energizing the filament, and at least one of the filament energization wirings can be switched between connection and disconnection. Can be solved. In particular, a mechanism capable of switching between connection and disconnection of at least one can be solved by using a bimetal alloy. Alternatively, the problem can be solved by providing a mechanism that cools at least one electrode of the electrostatic lens that exists in the ion extraction direction from the gas molecule ionization chamber and faces the gas molecule ionization chamber.

  In a field ion source, the fourth problem of the present invention, which is to reduce the mechanical vibration of the emitter tip, is a refrigerant in which the coolant of the mechanism for cooling at least one electrode of the electrostatic lens is in a gaseous state at room temperature and atmospheric pressure. This can be solved by making the gas a solid coolant. Alternatively, the problem can be solved by making the emitter tip holding mechanism movable relative to the gas molecule ionization chamber and coupling the emitter tip holding mechanism to the cooling mechanism with a mechanically deformable member.

  According to the present invention, there is provided a gas ionization ion source capable of achieving both an increase in conductance during rough evacuation and a reduction in the diameter of the extraction electrode hole from the viewpoint of increasing the ion current, and obtaining a large current ion beam. Is done.

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

  In addition, a gas electrolysis ion source capable of realizing a cryogenic emitter tip and obtaining a large current ion beam is provided. In addition, a gas electrolysis ion source and an ion microscope capable of reducing mechanical vibration and enabling high-resolution observation are provided. In addition, a gas electrolysis 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. FIG. 3 is a schematic diagram around the emitter tip of the field ion source of Example 1. 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 (at the time of cutting) of the field ion source of Example 1. FIG. 1 is a schematic structural diagram of a field ion source of Example 1. FIG. FIG. 3 is a diagram illustrating a cooling mechanism of the present ion source according to the first embodiment. It is a figure explaining operation of the on-off valve (open state) of the gas molecule ionization chamber top plate of Example 1. FIG. It is a figure explaining operation of the on-off valve (closed state) of the gas molecule ionization chamber top plate of Example 1. FIG. 6 is a configuration diagram of a gas field ion source of Example 3. FIG. 4 is a schematic configuration diagram of a gas field ion source of Example 3. FIG. FIG. 6 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. 6 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. 6 is a configuration diagram of a combined apparatus of an ion beam microscope and an electron beam microscope of Example 4. FIG. 10 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. 10 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. 10 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. 6 is a configuration diagram of an ion beam microscope of Example 5.

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

  FIG. 1 shows a schematic configuration diagram of an ion beam microscope according to 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 pump 12 and a sample chamber vacuum pump 13 are attached. Needless to say, the inside of the ion beam irradiation system column 2 is also maintained in a vacuum.

  As a device (or a section) for controlling the microscope, a field ion source control device 91, a refrigerator control device 92, a lens control device 93, a beam limiting aperture control device 94, an ion beam scanning control device 95, a secondary device. An electronic detector control device 96, a sample stage control device 97, a vacuum 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 that displays an image generated based on the detection signal of the secondary particle detector 11, information input by the information input means, and the like.

  Here, the sample stage 10 rotates about a linear movement mechanism in two directions perpendicular to the sample mounting surface, a linear movement mechanism perpendicular to the sample mounting surface, a rotation mechanism in the sample mounting surface, and a tilt axis. Thus, a tilt function is provided that can vary the irradiation angle of the ion beam 14 onto the sample 9, and these controls are performed by the sample stage controller 97 in response to a command from the calculation processor 99.

First, emitter tip fabrication is described. The emitter tip is a tungsten wire with a diameter of about 100 to 400 μm and an axial orientation <111>, and the tip radius of curvature is sharply formed to several tens of nanometers. In yet another vacuum vessel, iridium is vacuum-deposited at the tip of the emitter tip. Then, when iridium atoms are moved to the tip of the emitter tip by high-temperature heating, a pyramid of nanometer order is formed by iridium atoms. This is called the nano pyramid. The tip of the nanopyramid is a single atom, but under this atom there is a layer of 3 or 6 atoms. Below that is a layer of 10 or more atoms.

  In this embodiment, tungsten fine wire and iridium are used, but molybdenum fine wire can also be used. In this embodiment, iridium is coated, but platinum, rhenium, osmium, palladium, rhodium, etc. can also be used. When helium is used as the ionization gas, it is important that the evaporation intensity of the metal is larger than the electric field intensity 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. It is possible to coat these metals by plating in a solution in addition to the vacuum deposition method. In addition, a nanometer-order pyramid at the tip of the emitter tip, that is, a nanopyramid, can also be applied by applying field evaporation in vacuum or ion beam irradiation, and can form tungsten or molybdenum nanopyramids. . For example, when a <111> tungsten wire is used, the tip is composed of three atoms.

  FIG. 2 is a schematic diagram around the emitter tip of the field ion source of the present embodiment. The periphery of the emitter tip of the present ionization ion source is constituted by 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 a support rod 26 of the filament mount.

  The extraction electrode 24 is disposed opposite to 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 opening / closing 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. The lid is made of a bimetal that deforms depending on the temperature, and the lid can be opened and closed by changing the temperature of the bimetal. Here, a room surrounded by the extraction electrode, the side wall, and the top plate is called a gas molecule ionization chamber. 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 the gas molecule ionization chamber. A gas supply pipe 25 is connected to the gas molecule ionization chamber. This gas supply pipe 2
5 supplies helium, which is an ionized gas. Here, as shown in FIG. 2, the gas molecule ionization chamber does not need to be configured independently of the extraction electrode, the side wall, and the top plate, 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 a 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 wiring of the field ion source of the present embodiment. An electric wire 33 is connected to the support rod 26 of the filament mount 23. The filament 22 can be energized by a power source 34, and the emitter tip 21 can be heated using heat conduction from the filament. Further, an ion high voltage power source 35 is connected to the electric 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 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. A bimetal that deforms depending on the temperature is used as a part of the material of the cutting mechanism 37, and the connection / cutting of the copper wire is switched by the temperature change of the bimetal.

  The wiring for energizing the resistance heater is connected to the copper thick wire 38 and the stainless steel thin wire 39 in the same manner as the filament wiring described above, and a cutting mechanism 40 is attached to the thick copper wire. Bimetal that deforms depending on temperature is used as a part of the material of this cutting mechanism function, and the connection / cutting 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 have the same potential as one end of the resistance heater. Can be applied. Further, even when the copper wire is cut, an extraction voltage can be applied to the extraction electrode 24 by the thin stainless steel wire 39.

Next, FIG. 4 shows a schematic structural diagram of the field ion source of the present embodiment. Emitter tip 21
Is suspended from the upper flange 51, and has a movable structure so that the emitter tip 21 can be adjusted in two horizontal and vertical directions, and the angle of the tip of the emitter tip. On the other hand, the extraction electrode 24 is fixed to the vacuum container. The filament mount 23 is insulated by a sapphire base 52. Needless to say, the ion source is a vacuum vessel, but there is a cooling transmission mechanism from the refrigerator in addition to the vacuum exhaust mechanism. The refrigerator 4 and the sapphire base 52 are connected by a copper cooling conduction rod 53 which is a good heat heat conductor. However, since the refrigerator is fixed to the vacuum vessel, the tip of the cooling conduction rod 53 and the sapphire base 52 are connected by a deformable copper mesh wire 54. As a result, the emitter tip 21 can be moved, and the copper mesh wire 54 can reduce the transmission of vibration at a high frequency of the refrigerator. In other words, there is an effect that an ion microscope capable of high resolution observation can be provided. From the viewpoint of reducing vibration transmission from the refrigerator, the extraction electrode 24 has a fixed structure with respect to the vacuum vessel, but the connection between the sapphire base 55 supporting the extraction electrode and the tip of the cooling conductor rod 53 of a good heat conductor is provided. Are also connected by a deformable copper mesh wire 56. As a result, an ion microscope capable of high-resolution observation can be provided.

  Next, the cooling mechanism of this ion source will be described with reference to 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. This produces an effect that 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. The second cooling stage is connected to the sapphire base 52 by the deformable copper mesh wire 54 via the copper cooling conduction rod 53 as described above, and finally cools the emitter tip 21. As described above, in the present 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 through a copper cooling conduction tube 57. The cooling conduction tube 57 is arranged 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 heat inflow due to thermal radiation into the gas molecule ionization chamber. Further, in FIG. 4, at least one electrode of the electrostatic lens 59 that exists 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, thereby reducing heat inflow due to thermal radiation to the gas molecule ionization chamber and the emitter tip. This realizes a cryogenic temperature of the emitter tip, provides a gas field ion source capable of obtaining a higher current ion beam, and thus provides an ion microscope capable of high-resolution observation.

  Next, the operation of this ion source is described. First, the operation of the opening / closing valve of the gas molecule ionization chamber top plate will be described with reference to FIGS. 6A and 6B. After the 21 prepared emitter tips are attached, the vacuum container 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 with respect to the vacuum exhaust system is larger than that when the gas molecule ionization chamber is closed. There is an effect that particularly rough exhaust of the chamber is possible in a short time.

  After evacuation, the extraction electrode 24, the side wall 28, the top plate 29, etc. are heated by a resistance heater 30 outside the side wall of the gas molecule ionization chamber to degas. At this time, the vacuum vessel 61 is simultaneously heated by another resistance heater arranged in the atmosphere, thereby improving the vacuum degree of the vacuum vessel and lowering the residual gas concentration. This operation has the effect of improving the temporal stability of the ion emission current. In this embodiment, the resistance heater 30 is disposed outside the gas molecule ionization chamber. As a result, the gas molecule ionization chamber can be evacuated to a higher vacuum because there is no degassing from the resistance heater itself as compared with the case where it is arranged inside. Further, although the resistance heater is used in this embodiment, a heating lamp may be disposed to degas the extraction electrode and the side wall. 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, and the power supply can be simplified. Alternatively, a high temperature inert gas may be supplied from the gas supply pipe to degas the extraction electrode and the side wall. According to this, since the gas heating mechanism can be arranged at the ground potential, the surrounding structure of the extraction electrode can be simplified, and there is no need to apply a high voltage to the wiring, and the power supply can be simplified.

  Next, heating of the gas molecule ionization chamber and the vacuum vessel is stopped, and after a sufficient time has passed, the refrigerator is operated to cool the emitter tip, extraction electrode, 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 conductance of the gas molecule ionization chamber is smaller than that of the vacuum exhaust system. For this reason, 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 to the emitter tip surface by a strong electric field and reaches the vicinity of the tip of the emitter tip with the strongest electric field. Therefore, helium is ionized and the ion beam can be extracted through a small hole in the extraction electrode. Here, when the electric field strength is adjusted, helium ions are generated near 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 region, the current emitted from the unit area and unit solid angle can be increased. This is an important characteristic for obtaining an ion beam with a fine diameter and a large current on a sample.

  In particular, when iridium or the like is deposited on tungsten, the nanopyramid structure in which one atom exists at the tip can 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, an ion source having an iridium nanopyramid structure in which helium gas is concentrated and supplied to one atom can increase the current emitted from the unit area and unit solid angle. In other words, if the emitter tip is formed by depositing iridium, platinum, rhenium, osmium, or the like on tungsten, an effect suitable for reducing the beam diameter on the sample of the ion microscope or increasing the current can be obtained.

  Next, the ion beam 14 that has passed through the lens passes through the scanning deflection electrode 301, and further passes through a small-diameter hole in the aperture plate 302 and collides with the movable shutter 303. Here, when secondary particles 304 such as secondary electrons generated by a movable shutter are detected by a secondary shutter while scanning with an ion beam to obtain a secondary particle image, an 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. 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 radiation 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 of the atoms are selected and passed through the aperture. You can also The same effect can be obtained 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. In particular, if a fine projection is provided on a movable shutter and the secondary particle image 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.

  In addition, as described above, since the degree of vacuum is high outside the gas molecule ionization chamber in this ion source, the ion beam collides with the gas in the vacuum and the neutralization rate is small. There is an effect that 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 extraction electrode can be lowered, and the sample can be irradiated with a large 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 this embodiment has the advantage that it can be automatically opened and closed without any other mechanical mechanism by cooling the ion source. In particular, there is a feature that the structure can be made simple so as to be suitable for applying a high voltage.

  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 automatically performed by ion source cooling because bimetal that deforms with temperature is used as a part of the material of the wiring cutting mechanism function. Each is given a potential by a stainless steel wiring. As a result, 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, there are the effects of improving the brightness of the ion source and increasing the current of the ion beam. As a result, a gas field ion source capable of obtaining a high-current ion beam is provided, and thus 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 processor 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. Thereby, 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 reduced to 1 nm or less. The fine ion beam is scanned by the ion beam scanning electrode 7 to be detected by the secondary particle detector 11 such as secondary electrons emitted from the sample, and the brightness of the secondary particle detector 11 is modulated to display an image on the computer 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 that it uses ions emitted from the vicinity of one atom at the tip of the nanopyramid. In other words, the ion emission region is narrow and the ion light source is as small as nanometers or less. For this reason, if the ion source is focused on the sample at the same magnification or the reduction ratio is increased to about one half, the characteristics of the ion source can be utilized to the maximum. 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 rate is reduced to 1/10 or less at most. In this case, the oscillation of the emitter tip of the ion source is reduced to 1/10 or less on the sample. For example, even if the emitter tip vibrates by 10 nm, it is less than 1 nm on the sample, and the influence on the beam diameter of 5 nm is negligible. 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 1/2, and becomes large with respect to the beam diameter. Therefore, the conventional apparatus does not fully consider this point, and the observation of the good sample surface has not necessarily been realized. In the present embodiment, since countermeasures against this vibration are sufficient, there is an effect that high-resolution observation of the sample surface that fully exhibits the performance of the ion source is realized.

  Although the extraction electrode of the field ion source is fixed to the vacuum vessel, the emitter tip is movable with respect to the extraction electrode by connecting the emitter tip mount with a copper mesh wire. This makes it possible to adjust the position of the emitter tip with respect to the small hole of the extraction electrode and to adjust the axis of the optical system, and it is needless to say that it is possible to form a finer beam.

  The pulse tube refrigerator may be either a GM type or a Stirling type. In this embodiment, a refrigerator having two cooling stages has been described. However, 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 the rough evacuation and the reduction in the diameter of the extraction electrode hole from the viewpoint of increasing the ion current, and the gas ionization ionization that can obtain a large current ion beam. An ion source is provided.

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

  In addition, a gas electrolysis ion source that realizes a very low temperature emitter and obtains a large current ion beam is provided. In addition, a gas electrolysis 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. However, in some cases, it is not always satisfactory to minimize the beam diameter of the ion beam. In the second embodiment, a refrigerator in which a GM type refrigerator and a helium gas spot are combined is used instead of the pulse tube refrigerator.

  This GM refrigerator has a first cooling stage that is cooled to about 50K and a second cooling stage that can be cooled to 4K. These cooling stages are covered by a sealed pot. And the pot is filled with helium gas. That is, the GM refrigerator cools the helium gas, and the helium gas cools the pot outer wall. 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 refrigerator vibrates, the 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 refrigerator. As described in the first embodiment, the helium gas spot is connected to the emitter tip mount by a copper mesh wire via a copper cooling conduction rod, and cools the emitter tip. As described in the first embodiment, the mechanical vibration is further reduced by connecting with a copper mesh wire. The gas field ion source using this cooling system has the feature that the mechanical vibration of the emitter tip can be further reduced.

  As described above, according to the present embodiment, a gas electrolysis ion source and an ion microscope capable of reducing mechanical vibration and performing high-resolution observation are provided.

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

  7 is a block diagram of the gas field ion source of the present embodiment. In this ion source, a 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 vessel, 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 inside of the solid nitrogen tank is evacuated from the vacuum exhaust port 83. As a result, liquid nitrogen solidifies into solid nitrogen 84. Solid nitrogen in the evacuated environment is sublimated by the heat inflow from the emitter tip, extraction electrode and 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 reducing mechanical vibration and enabling high-resolution observation are provided.

  Next, an example is described 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 ion source of the present embodiment. In this ion source, the emitter tip 21 is directly connected to the liquid helium tank 85 and cooled. The solid nitrogen 83 radiates and shields the emitter tip 21, 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 for producing solid nitrogen is the same as that described above. In this embodiment, solid nitrogen cools the radiation shield, but vibration due to foaming does not occur as well. Further, liquid helium is separately connected with a liquid helium dua and 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 reducing mechanical vibration and enabling high-resolution observation are provided.

In addition, 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 that requires high resolution. In this case, the solid nitrogen consumption can be reduced. 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, a gas electrolytic ionization ion source and an ion microscope capable of reducing mechanical vibration and enabling 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 a low temperature suitable for increasing the current of the helium ion beam can be realized.

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

  The configuration and operation of this ion beam microscope are substantially the same as those in the first embodiment. In this apparatus, a scanning electron microscope is attached to the vacuum sample chamber. This scanning electron microscope includes 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 disposed 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 tilt function, and the sample surface can be made perpendicular to the electron beam 102. In this device, helium or hydrogen ion beam and 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 onto the sample 9. At this time, the electron beam 102 is irradiated onto the sample cross section while 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 is converted to the luminance of the image. Once converted, 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. First, the ion microscope image is stored in the calculation processing device 99, and then the feature point in the stored ion microscope image is observed in the scanning electron microscope image while observing the scanning electron microscope image. The direct current 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 again with the ion microscope. Here, the scanning deflector is used to match the electron beam irradiation position with the ion beam irradiation position, but an adjustment deflector may be provided separately. In this case, since deflection control is performed to control only the direct current component of the deflector, there is an effect that it is easy to produce a power source having lower noise than the power source of the scanning deflector that controls alternating current.

  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. Both result in roughly equivalent surface information, but the secondary electron yield from ion beam excitation and the secondary electron yield from electron beam excitation are different, giving different information in detail, allowing more detailed analysis of the sample .

  10B, the ion beam irradiation axis 1003 of the ion microscope is substantially perpendicular to the installation plane of the apparatus, that is, the XY plane of FIG. 10A, and the electron beam irradiation axis 1004 is installed as the apparatus. It is arranged in an inclined direction with respect to the surface. This relates to the characteristics of the ion microscope already described. 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. In other words, the ion emission region is narrow and the ion light source is as small as nanometers or less. For this reason, if the ion source is focused on the sample at the same magnification or the reduction ratio is increased to about one half, the characteristics of the ion source can be utilized to the maximum.

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

  As a result of vibration simulation and experimental evaluation, it was found that high resolution observation was possible when the ion beam irradiation axis of the ion microscope was approximately perpendicular to the installation surface of the device and the sample was 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 light source diameter on the sample than the ion microscope, and the influence of the vibration of the electron gun is small. Was found to be smaller than the ion microscope. These are new issues to be investigated because this is an ion microscope that uses 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. Therefore, it is possible to realize a high-resolution observation of the sample surface that fully exhibits the performance of the ion source.

  Further, 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, in an ion microscope, when the acceleration voltage of ions is several tens of kV, X-rays are hardly emitted and elemental analysis is difficult. According to this apparatus, there is an effect that ultra-high resolution observation and elemental analysis by an ion beam can be performed simultaneously. 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 control device 99 at the same time, a more detailed sample can be obtained. Analysis becomes possible.

  Further, in this apparatus, when the vacuum sample chamber is divided into two in the electron beam irradiation system column mounting direction and the other direction with the electron beam irradiation system column mounting direction as the center, that is, by the center line 1001 of the sample chamber in FIG. In this case, the X-ray detector mounting position in the vacuum sample chamber is stored in the electron beam irradiation system column mounting direction, that is, on the right side of the center line 1001 in FIG. 10A. With such an arrangement, the X-ray analysis can be performed even when the sample stage is tilted in the direction of the electron beam column and the electron beam is irradiated perpendicularly to the sample for observation.

  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 almost the same position on the sample. If the beam irradiation axis and the electron beam irradiation axis are arranged at positions that do not substantially intersect on the sample, the objective lenses can be brought closer to the sample because there is no mechanical interference with each other, and the resolution of each microscope can be reduced. There is an effect that it can be improved.

Further, the feature of this apparatus is that a refrigerator is installed in a 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. 10A. The direction is different from the right side of the central axis 1001 on the axis 1002. That is, no refrigerator is arranged on the right side of the central axis 1001 on the central axis 1002 in FIG. 10A. As shown in FIG. 10A, it is most preferable to arrange on the left side which is the opposite direction. This is also a result obtained as a result of vibration simulation and experimental evaluation taking into account that the vibration of the refrigerator affects the resolution of the scanning electron microscope. The irradiation axis direction 1004 of the refrigerator is shown in FIG. 10A. This is because if the refrigerator is arranged on the right side of the central axis 1001 on the central axis 1002 projected on the XY plane, the observation resolution of the scanning electron microscope deteriorates due to the influence of vibration.

  As described above, according to the present embodiment, 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 apparatus analysis apparatus suitable for observing and analyzing defects and foreign matters, And an inspection device are provided.

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

  The configuration and operation of this ion beam microscope are substantially the same as those in the first embodiment. Note that the arrangement of the refrigerator 4 is characteristic, and as shown in FIG. 12B, the refrigerator 4 was installed in a horizontal 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 that emits 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 ion beam irradiation system column for processing. In the vacuum sample chamber, a first sample stage 10 on which a sample 9 is placed, a secondary particle detector. 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 a sample on the first sample stage using ion beam processing, a manipulator 209 for driving the probe, and a second sample on which a micro sample piece is placed. A 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 substantially the same position on the sample. Needless to say, the inside of the ion beam irradiation system column 206 is also maintained in a 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, the linear movement in the two orthogonal directions within the first sample mounting surface and the straight line in the direction perpendicular to the sample mounting surface are performed. The movement and the rotation within 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, the ion beam is focused near the center of the objective lens by the condenser lens 202. The ion beam passes through a stencil mask 205 having a rectangular hole. The objective lens 203 is controlled under conditions for projecting the stencil mask 205 onto the sample. In this way, a rectangular shaped ion beam is irradiated on the sample. When this shaped ion beam is continuously irradiated, a rectangular hole is formed in the sample.

  In this device, the observation function using an ion microscope is also used for observing the cross section of a sample defect or foreign material, or observing 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 a sample by an ion beam processing apparatus, fix it to the probe, and place it on the second stage using 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 an electron beam.

  In particular, the conventional electron beam scanning microscope has a problem that the trajectory of the gallium ion beam is separated into two because the magnetic field of the electron lens separates the gallium isotope by mass. As a result, the conventional FIB-SEM device has a problem that gallium processing cannot be performed with high accuracy, or a SIM image by a gallium ion beam is doubled. In the ion microscope of this embodiment, an electrostatic lens is used instead of a magnetic lens, so that such problems can be solved and high-precision processing and high-resolution image observation become possible.

  In the above embodiment, the ion microscope scans the ion beam to detect secondary electrons, but may detect ions that have passed through the thin film sample. Further, if secondary electrons generated on the back surface of the thin film are detected, the surface of the back surface of the sample can be observed.

  12B, 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, and the ion beam irradiation axis 1005 of the gallium focused ion beam. Is arranged in an inclined direction with respect to the installation surface of the apparatus. In order to take advantage of the high-resolution features of this ion microscope, vibrations of the sample, field ionization ion source, and ion beam irradiation system column of the ion microscope become issues. 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. In other words, the ion emission region is narrow and the ion light source is as small as nanometers or less. For this reason, if the ion source is focused on the sample at the same magnification or the reduction ratio is increased to about one half, the characteristics of the ion source can be utilized to the maximum.

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

  As a result of vibration simulation and experimental evaluation, it was found that high resolution observation was possible when the ion beam irradiation axis of the ion microscope was approximately perpendicular to the installation surface of the device and the sample was placed horizontally. In particular, the tilted gallium liquid metal ion source has been found to oscillate more than the field ionization ion source. However, as already mentioned, the gallium liquid metal ion source has a reduction rate for focusing the ion source diameter on the sample. It was found to be smaller than the ion microscope and less affected by the vibration of the gallium liquid metal ion source than the ion microscope. These are new issues to be investigated because this is an ion microscope that uses 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. Since the countermeasures are sufficient, there is an effect that high-resolution observation of the sample surface that fully exhibits the performance of the ion source is realized.

  In addition, the feature of this apparatus is that a refrigerator is installed in a direction perpendicular to the ion beam irradiation axis of the ion microscope, and the direction of the irradiation axis direction 1005 of the gallium focused ion beam is projected onto the XY plane of FIG. 12A. The center axis 1002 is in a different direction from the left side of the center axis 1001. That is, a refrigerator is not arranged on the left side of the central axis 1001 on the central axis 1002 in FIG. As shown in FIG. 12A, it is most preferable to arrange on the right side in the opposite direction. 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 device. This is because it has been found that if the refrigerator is arranged on the left side of the central axis 1001 on the central axis 1002 in which 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.

  In this embodiment, a gallium liquid metal ion source is used. However, an inert gas such as argon or xenon, or a plasma ion source that generates 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, in an ion beam processing apparatus that irradiates a silicon ion wafer with a gas ion beam while filling a hole formed after extracting a minute sample by irradiating a silicon wafer with a deposition gas. The surface of the hole can be flattened by measuring the three-dimensional shape of the surface formed by the ion microscope using an ion microscope and controlling the inert gas ion beam based on the measurement result. I understood. That is, there is an effect that even if the processed silicon wafer is returned to the process of the semiconductor device, the manufacturing is not adversely affected. In this case, it is not always necessary to use an ion beam of an ion microscope, and the same effect can be obtained even with an electron beam of an electron microscope. The method of measuring the three-dimensional shape can be measured by parallax between two images obtained by illuminating the sample by inclining the sample or by illuminating the ion beam or electron beam. Or you may utilize the difference in the focus by sample height. In the method of controlling the ion beam so as to flatten the obtained three-dimensional shape of the sample, the irradiation position and the irradiation time may be appropriately set for each place in the scanning control. For example, the ion beam may be irradiated for a longer time at a place lower than the flat surface. As described above, according to the present invention, an ion beam processing apparatus that can fill a hole processed by an ion beam flatly and return the processed wafer to the manufacturing process line is provided.

  It was also found that the sound of the compressor 1100 sending helium to the refrigerator 4 vibrates the field ion source and deteriorates its resolution. For this reason, as shown in FIG. 13, a device cover 1101 for spatially separating the compressor of the refrigerator and the field ion source is provided. This provides a gas electrolysis ion source and ion microscope that shields the compressor sound of the refrigerator, further reduces the influence of vibration, and enables high-resolution observation.

  In the above embodiment, a turbo molecular pump is used as a vacuum pump for evacuating the field ion source. However, if the non-evaporable getter pump and the ion pump are noble pumps, the influence of vibration is further reduced. It has been found that a gas electrolysis ion source and an ion microscope capable of observing the resolution are provided. Here, the non-evaporable getter pump is a vacuum pump configured by using an alloy that adsorbs gas when activated by heating. When helium is used as the ionization gas of the field ion source, helium is present in a relatively large amount in the vacuum vessel. However, since the non-evaporable getter pump does not exhaust most of the helium, the getter surface may be saturated with adsorbed gas molecules. There is an 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 ion emission current is stabilized by reducing the impurity gas in the vacuum vessel. However, the non-evaporable getter pump exhausts residual gases other than helium at a high exhaust speed, but this alone stops helium 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 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 exhaust speed, and the structure becomes complicated. This time, by combining non-evaporable getter pump and ion pump or noble pump, a compact and low-cost ion source was realized. Conventionally, due to insufficient consideration for mechanical vibration, the performance of an ion microscope could not be obtained sufficiently. However, the present invention provides a gas electrolysis ion source and an ion microscope capable of reducing mechanical vibration and enabling high-resolution observation. Is done.

  As described above, according to the present invention, it is possible to achieve both the increase in conductance during rough evacuation and the reduction in the diameter of the extraction electrode hole from the viewpoint of increasing the current of the ions, and the gas electrolysis ionized ion that provides a large current ion beam. A source is provided.

Further, when a non-evaporable getter pump is arranged in the middle of the helium gas supply pipe, an impurity gas is reduced in the supplied gas, thereby providing a gas electrolysis ion source and an ion microscope in which ion emission current is stabilized.
In addition, a high vacuum is achieved in the gas molecule ionization chamber, and a gas electrolytic ion source capable of highly stable ion emission is provided. In particular, it was found that if the non-evaporable getter material is built in the ionization chamber, the ionization chamber becomes a high vacuum 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 and heating the non-evaporable getter material and using the hydrogen released as the ionized gas.

  In addition, a gas electrolysis ion source that realizes a very low temperature emitter and obtains a large current ion beam is provided. In addition, a gas electrolysis ion source and an ion microscope capable of reducing mechanical vibration and enabling high-resolution observation are provided.

  In addition, an apparatus and a method for observing a cross section suitable for forming a cross section by processing with an ion beam and observing the cross section with an ion microscope at a 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 and elemental analysis with an ion microscope is provided.

  As described above, according to the present invention, a sample that can be observed by an ion microscope, a sample that can be observed by an electron microscope, and an elemental analysis can be measured by a single device, and a structural dimension on the sample is measured and observed and analyzed. An analysis apparatus, ion beam length measuring apparatus or inspection apparatus suitable for the above is provided.

  In addition, in an inspection device that measures the dimensions of a sample by irradiating the sample emitted from the gas ionization ion source to the sample in the semiconductor device manufacturing process to detect the particle emitted from the sample, It was found that when the energy is less than 1 kV, damage to the sample can be reduced, and the electrical characteristics of the device are not adversely affected even if the wafer after measurement is returned to the manufacturing process. In particular, when the ion acceleration voltage is applied to the sample such that the ion acceleration voltage is 2 kV positive and the sample applied voltage is 1.5 kV positive and the energy of the ion beam with respect to the sample is less than 1 kV, ion irradiation is performed. There is an effect that the current can be increased and the measurement can be performed with high accuracy. In addition, compared with the conventional measurement using an electron beam, the obtained image has a deep depth of focus, so that an accurate measurement can be performed. In particular, when a hydrogen ion beam is used, there is an effect that the sample surface is reduced and the measurement can be performed with high accuracy. As described above, according to the present invention, an ion beam length measuring device or an inspection device suitable for measuring a structural dimension on a sample is provided.

DESCRIPTION OF SYMBOLS 1 ... 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 ... Two 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 ... 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 steel thin wire 37 ... Cutting mechanism 38 ... Copper wire 39 ... Stainless steel 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 controller 93 ... Lens controller 94 ... Beam limiting aperture controller 95 ... Ion beam scanning controller 96 ... Secondary Electron detector controller 97 ... Sample stage controller 98 ... Vacuum pump controller 99 ... Calculation processor 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 Directional device 205 ... Stencil mask 206 ... Processing ion beam irradiation system column 207 ... Depo 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 (1)

A vacuum vessel, an extraction electrode that extracts an ion beam, a gas field ionization ion source that ionizes gas molecules in an electric field at the tip of the emitter tip,
A cooling mechanism for cooling the emitter tip;
A focusing lens system for focusing the ion beam extracted from the emitter tip;
A sample chamber in which the sample is placed;
A charged particle detector for detecting secondary charged particles emitted from the sample;
A heat transfer part connected to the emitter tip and transferring heat to the emitter tip;
The cooling mechanism has an exhaust part that solidifies the coolant by lowering the atmospheric pressure, and cools the emitter tip by cooling the heat transfer part through the solidified coolant. Ion beam device.

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