JPWO2013069410A1 - Cooling device, ion microscope, observation device, or inspection device - Google Patents

Abstract

An object of the present invention relates to providing a cooling device that suppresses transmission of vibration to an object to be cooled, an ion microscope, an observation device, or an inspection device using the same.
A cooling heat conductor (53, 406) thermally coupled to the object to be cooled stored in the vacuum vessel, at least a part of which is cooled to a temperature lower than room temperature; A heat exchanger (405, 414) thermally coupled to the cooling heat conductor and mechanically coupled directly or indirectly to the vacuum vessel; and at least the object to be cooled to the heat exchanger A reciprocating pipe (403, 407, 413, 415) for supplying a refrigerant having a temperature lower than room temperature for cooling the refrigerant and recovering the refrigerant from the heat exchanger, and a refrigerator (401) for cooling the refrigerant. A refrigerant holding circuit mechanism (500, which is provided in the reciprocating pipe between the refrigerant circulation circuit in the path and the heat exchanger and the refrigerator in the refrigerant circulation circuit and is flexible in a two-dimensional direction or a three-dimensional direction. 508) and Cooling device, ion microscope, observation device using the same, or inspection apparatus is provided.

Description

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

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

  In addition, if an electron or ion beam is irradiated on a sample and 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 a 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 because it has a narrow ion energy width and a small ion generation source size, so that a fine beam is expected. 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 ion source. Non-Patent Document 1 discloses that a minute protrusion at the tip of an emitter tip is manufactured using a second metal different from the emitter tip material. A high-brightness ion source is realized by creating a nano-pyramid structure of atoms at the tip of the emitter tip.

  Non-Patent Document 2 discloses a scanning ion microscope equipped with a gas electrolytic ion source that emits helium ions.

  Patent Document 2 discloses a mechanism in which a bellows is disposed in an ionization chamber in a gas electrolytic ionization ion source. However, the ionization chamber is in contact with the room temperature via the vacuum sample chamber wall, and the problem that the gas supplied to the ionization chamber collides with the high-temperature vacuum sample chamber wall is not mentioned. In addition, there is no description relating to the inclination of the emitter tip.

  Patent Document 3 discloses a direction adjusting mechanism that makes the axial direction of an ion source variable in a gas electrolytic ion source. However, the ionization chamber is in contact with the room temperature via the vacuum sample chamber wall, and the problem that the gas supplied to the ionization chamber collides with the high-temperature vacuum sample chamber wall is not mentioned. Further, the extraction electrode is inclined as the ion source changes in the axial direction.

  Patent Document 4 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 a capacitor. A gas ionization ion source is disclosed that can prevent discharge between the emitter tip and the extraction electrode after the shunting process.

  Patent Document 5 discloses a structure in which a vibration isolator is provided between a base plate on which a charged particle device main body is mounted and a device mount in a charged beam device. However, there is no related description about the cooling mechanism of the charged particle source.

  Further, the sample can be finely processed by irradiating the sample with an ion beam. This processing applies the action of particles constituting the sample being released from the sample by the sputtering action of ions. For this processing, a liquid metal ion source (hereinafter LMIS) was used. It is preferable to use a focused ion beam apparatus (hereinafter referred to as FIB). In recent years, a FIB-SEM apparatus that combines a SEM and a focused ion beam has come to be used. In this FIB-SEM apparatus, FIB is irradiated to form a square hole at a desired location, and the cross section can be observed by SEM.

  For example, Patent Document 6 proposes an apparatus for observing and analyzing defects and foreign matters 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. ing.

  Patent Document 7 discloses a technique for extracting a micro sample for observation with a transmission electron microscope from a bulk sample using an FIB and a probe.

  Patent Document 8 discloses a cooling technique in which a body to be cooled of a superconducting magnet and a refrigerator are separated and both are thermally connected by a detachable vacuum heat insulating pipe. There is no disclosure of a structure for preventing vibrations of the refrigerator when the both are mounted for cooling operation.

  Patent Document 9 discloses a structure in which a high-frequency receiving coil for NMR is an object to be cooled, and this daily cooling body is thermally connected in a vacuum space to a cooling stage cooled by a refrigerant. Yes. However, there is no disclosure of a structure that hermetically isolates both the vacuum space with the cooled object and the vacuum space with the cooling stage with a partition wall.

JP 58-85242 A Japanese Patent Publication No. 3-74454 JP 62-114226 A JP-A-1-221847 JP-A-8-203461 JP 2002-150990 A International Publication No. 99/05506 JP-A-9-312210 JP-A-4-230880

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.

  The inventor of the present application diligently studied to increase the flow rate and to stabilize the ion microscope using a gas field ion source, and as a result, the following knowledge was obtained.

  That is, when cooling the emitter tip that is the object to be cooled using the cooling device, the vibration on the cooling device side travels through a pipe that exchanges refrigerant between the cooling device and the gas field ionization ion source periphery, The inventors of the present application have found a problem that the gas field ion source is vibrated. This problem is neither described nor suggested in the above prior art documents.

  An object of the present invention relates to providing a cooling device that suppresses transmission of vibration to an object to be cooled, an ion microscope, an observation device, or an inspection device using the same.

  According to one aspect of the present invention, the cooling heat that is housed in the vacuum vessel and that is thermally coupled to the object to be cooled, at least a portion of which is cooled to a temperature lower than room temperature. A conductor, a heat exchanger thermally coupled to the cooling heat conductor and mechanically coupled directly or indirectly to the vacuum vessel, and at least the object to be cooled to the heat exchanger. A refrigerant circulation circuit having a reciprocating pipe for supplying a refrigerant having a temperature lower than room temperature to be cooled and collecting the refrigerant from the heat exchanger, and a refrigerator for cooling the refrigerant in its path; A cooling device provided in the reciprocating pipe between the heat exchanger and the refrigerator, and having a bending holding structure mechanism that is flexible in a two-dimensional direction or a three-dimensional direction, an ion microscope using the same, and an observation device Or an inspection device is provided

  ADVANTAGE OF THE INVENTION According to this invention, the cooling device which suppressed transmitting a vibration to a to-be-cooled object, an ion microscope using this, an observation apparatus, or an inspection apparatus can be provided.

It is a figure which shows the schematic block diagram of the ion microscope which has a cooling device as 1st embodiment. It is a figure which shows the control apparatus which controls the ion microscope as 1st embodiment. It is a figure which shows the schematic structure figure of the gas field ionization ion source in the ion microscope as 1st embodiment. It is a figure which shows the schematic structure figure of the gas field ionization ion source containing the freezing mechanism which cools the emitter tip etc. of the gas field ionization ion source as 1st embodiment. It is a figure which shows the schematic block diagram of the bending possession structure mechanism used with the ion microscope as 2nd embodiment. It is a figure which shows the schematic block diagram of the cooling mechanism periphery of the ion microscope as 3rd embodiment.

  FIG. 1 is a diagram showing a schematic configuration diagram of an ion microscope having a cooling device as a first embodiment. The present ion microscope is generally composed of a gas field ionization ion source 1, an ion beam irradiation system column 2, a vacuum sample chamber 3, and the like. The gas field ionization ion source 1 is connected to an end portion 420 of a transfer tube 404 that is one of the components of the cooling mechanism 100 as a cooling device.

  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. Inside 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. The gas field ionization ion source 1 is provided with an ion source evacuation pump 12 and the vacuum sample chamber 3 is provided with a sample chamber evacuation pump 13. The inside of the ion beam irradiation system column 2 is also maintained in a vacuum.

  For example, a helium compressor (compressor) 16 using helium gas as a working gas is installed on the floor 20. The helium compressor 16 supplies high-pressure helium gas to the Gifford-McMahon type (GM type) refrigerator 401 through the pipes 101 and 102, for example. Further, the high-pressure helium gas periodically expands inside the GM refrigerator 401 to generate cold, and the low-pressure helium gas that has been expanded to a low pressure is recovered by the helium compressor 16 through the pipe 101. Is done.

  Helium gas, which is a working gas serving as a working refrigerant, is cooled using the GM refrigerator 401, the heat exchanger 402, the heat exchanger 409, the heat exchanger 410, and the heat exchanger 412. The compressor unit 399 circulates the working gas.

  The helium gas, which is pressurized by the compressor unit 399 and is a working gas at a normal temperature of 0.9 MPa (temperature 300 K), for example, flows into the heat exchanger 402 through the pipe 400 and returns to the later-described low-temperature helium gas and heat. It is exchanged and cooled to a temperature of about 60K. The helium gas cooled to 60 K passes through the refrigerant circulation pipe 403 and flows into the bending holding structure mechanism 500. In the bending holding structure mechanism 500, here, a copper pipe is connected to a coiled pipe 501 having a vertical winding axis in the paper surface and a copper pipe in the horizontal direction of the paper surface. It is comprised by the coiled piping 502 which has an axis | shaft. The bending holding structure mechanism 500 is configured as a biaxial bending holding structure mechanism in an upward vertical direction (hereinafter also referred to as Y direction) and a horizontal direction (hereinafter also referred to as X direction) in the plane of the paper. The coiled pipe 501 and the coiled pipe 502 are subjected to a conditioning treatment heated at a high temperature after bending, and have a structure that is very soft and has a flexure that can absorb a minute displacement. After passing through the coiled pipe 501, the pipe 403 through which helium gas circulates through the coiled pipe 502 is guided into the heat-insulated transfer tube 404.

  A fixed support body 504 integrated with the inside of the inlet flange 503 of the transfer tube 404 is provided. The pipe 403 is configured to pass through a through portion provided in the fixed support body 504 and be integrated and fixed to the fixed support body 504 at the through portion. The inlet flange 503 is configured to be connected to a vacuum heat insulating container 416 as a vacuum container through a bellows pipe 505 in a vacuum airtight state. The vacuum heat insulating container 416 is configured to accommodate at least a part of the reciprocating pipe and the refrigerator.

  Here, the inlet flange 503 is configured to be firmly fixed and supported by a fixed support body 419 fixed to a support body 418 fixed to and supported by the base plate 18.

  The helium gas is transported through the pipe 403 and flows into the heat exchanger 405 disposed in the vicinity of the gas field ion source 1 in the transfer tube 404. Here, the cooling heat conductor 406 thermally integrated with the heat exchanger 405 is cooled to a temperature of about 65K, and the radiation shield 58 and the like are cooled.

  The heated helium gas flows out of the heat exchanger 405, flows through the pipe 407, and flows into the holding structure mechanism 500 side. The pipe 407 is an inlet flange 503 portion, passes through a through portion provided in the fixed support body 504, and is integrated and fixed to the fixed support body 504 at the through portion. After that, it flows again into the bending holding structure mechanism 500, and in the bending holding structure mechanism 500, a copper coiled pipe 506 having an axis of a winding direction in the vertical direction upward in the plane of the paper, and connected to the horizontal, the horizontal plane of the drawing. It flows into a copper coiled pipe 507 having a winding axis in the direction. This structure is an in-plane X-Y biaxial deflection holding structure mechanism. The coiled piping 506 and the coiled piping 507 are subjected to a conditioning treatment heated at a high temperature after bending, and have a structure that is very soft and has a flexure that can absorb a minute displacement.

  After passing through the coiled pipe 506, the helium gas passing through the coiled pipe 507 flows into the pipe 407 where it circulates.

  After that, it flows into the heat exchanger 409 thermally integrated with the first cooling stage 408 of the GM refrigerator 401 through the pipe 407, is cooled to a temperature of about 50K, and flows into the heat exchanger 410.

  Here, heat is exchanged with a return low-temperature helium gas, which will be described later, and the temperature is cooled to about 15 K, and then flows into the heat exchanger 412 that is thermally integrated with the second cooling stage 411 of the GM refrigerator 401. Then, the temperature is cooled to about 9 K and flows into the pipe 413.

  The refrigerant circulation helium gas cooled to about 9K passes through the pipe 413 and flows into the bending holding structure mechanism 508. The flexure holding structure mechanism 508 has a coiled pipe 509 having a vertical winding axis in the plane of the paper as a pipe, and a winding axis in the horizontal direction of the plane. A coiled pipe 510 is used. The bending holding structure mechanism 508 is configured as an in-plane XY biaxial bending holding structure mechanism on the paper surface.

  The coiled pipe 509 and the coiled pipe 510 are subjected to a conditioning treatment heated at a high temperature after bending, and have a structure that is very soft and has a bending that can absorb a minute displacement. After passing through the coiled pipe 509, the pipe 413 through which helium gas circulates through the coiled pipe 510 is guided into the heat-insulated transfer tube 404. The pipe 413 is configured to penetrate through the through-hole of the fixed support body 504 and to be integrated and fixed to the fixed support body 504 at the through-hole.

  The helium gas cooled to about 9K is transported through the pipe 413 in the transfer tube 404 and flows into the heat exchanger 414 disposed in the transfer tube 404 near the gas field ion source 1.

  Here, the cooling heat conductor 53 as a cooling conductor rod of the good heat conductor thermally connected to the heat exchanger 414 is cooled to a temperature of about 10K. The cooling heat conductor 53 is connected to the emitter tip 21 as an object to be cooled through the copper mesh wire 54 and the sapphire base. That is, the cooling heat conductor 53 is the emitter tip 21 housed in the vacuum vessel, and is thermally connected to the emitter tip 21 at least a part of which is cooled to a temperature lower than room temperature. It is configured.

  The heated helium gas flows out of the heat exchanger 414, bends through the pipe 415, and returns to the side of the holding mechanism 508. The pipe 415 is an inlet flange 503 part, passes through a through part provided in the fixed support body 504, and is integrated and fixed to the fixed support body 504 at the through part.

  After that, it flows into the bending holding structure mechanism 508 again, and in the bending holding structure mechanism 508, a copper coiled pipe 511 having a winding axis in the vertical direction upward in the plane of the paper, and the horizontal direction in the drawing. It flows into a copper coiled pipe 512 having a winding axis.

  This structure is an in-plane X-Y biaxial deflection holding structure mechanism. The coiled pipe 511 and the coiled pipe 512 are subjected to a conditioning treatment heated at a high temperature after bending, and have a structure that is very soft and has a flexure that can absorb minute displacement. After passing through the coiled pipe 511, the helium gas that has passed through the coiled pipe 512 flows into the heat exchanger 410 and the heat exchanger 402 sequentially through the circulating pipe 415 and exchanges heat with the above-described helium gas to almost normal temperature. At a temperature of about 275 K, and is recovered by the compressor unit 399 through the pipe 415.

  The first cooling stage 408, the second cooling stage 411, the heat exchanger 402, the heat exchanger 409, the heat exchanger 410, the heat exchanger 412, the pipe 403, the pipe 407, the pipe 413, the pipe 415, and the bending holding described above. Low temperature parts such as the structure mechanism 500 and the bending holding structure mechanism 508 are accommodated in a vacuum heat insulating container 416 and are thermally connected to the transfer tube 404 via an inlet flange 503. Although not shown in the drawing, the heat insulating part such as a radiation shield plate or a laminated heat insulating material is provided in the vacuum heat insulating container 416, and the heat intrusion by the radiant heat from the room temperature part to the low temperature part is performed by the heat insulating part. It is comprised so that can be suppressed.

  Further, in the vicinity of the gas field ion source 1, the transfer tube 404 is configured to be supported and fixed to a support body 418 fixedly supported by the base plate 18 via a fixed support body 419.

  Preferably, the fixed support 419 is a heat insulator having a low thermal conductivity, such as a glass fiber epoxy resin (CFRP) material, and is made of a rigid body having a high hardness. The transfer tube 404 can be supported.

  Although not shown, a heat insulating material with low thermal conductivity is a plastic heat insulating material containing glass fiber and a laminated heat insulating material 30 for preventing radiant heat are laid in the transfer tube 404, and the heat insulating material and a laminated material for preventing radiant heat are laminated. The pipe 403, the pipe 407, the pipe 413, and the pipe 415 are configured to be fixedly supported by the heat insulating material 30.

  That is, the pipe 403, the pipe 407, the pipe 413, and the pipe 415 are configured to be fixedly supported by the support body 418 through the heat insulator, the laminated heat insulating material 30 for preventing radiant heat, the transfer tube 404, and the fixed support body 419. ing.

  The flange 421 of the end 420 on the gas field ion source 1 side of the transfer tube 404 is fixedly supported by a support 422 that is fixedly supported on the vacuum vessel wall of the gas field ion source 1. With this support structure, the pipe 403, the pipe 407, the pipe 413, and the pipe 415 fixedly supported inside the transfer tube 404 are fixed and supported on the vacuum vessel wall of the gas field ion source 1, and the pipe group Can be synchronized with the vibration of the gas field ion source 1.

  The cooling mechanism 100 includes a cold generating means for expanding the first high-pressure gas generated by the helium compressor 16 to generate cold, and cooling by the cold generated by the cold generating means, and is circulated by the compressor unit 399. The cooling mechanism which cools a to-be-cooled body with helium gas which is 2 moving refrigerant | coolants. The cooling heat conductor 53 is connected to the emitter tip 21 via the copper mesh wire 54 and the sapphire base.

  In addition, the pipe 403, the pipe 407, the pipe 413, and the pipe 415 are configured as reciprocating pipes, respectively, and supply a refrigerant having a temperature lower than room temperature for cooling the object to be cooled to the heat exchanger 405 and the heat exchanger 414, respectively. The refrigerant is recovered from the heat exchanger 405 and the heat exchanger 414. The heat exchanger 405 and the heat exchanger 414 are configured to be thermally coupled to the cooling heat conductor 53. Further, the heat exchanger 405 and the heat exchanger 414 are mechanically coupled directly or indirectly to the emitter tip 21 and configured to cool at least a part of the emitter tip 21 directly or indirectly. .

  Further, the GM refrigerator 401 is configured as a refrigerator that cools the refrigerant. Moreover, the piping 403, the piping 407, the piping 413, the piping 415, etc. are comprised as a refrigerant | coolant circulation circuit which has a reciprocating piping and a refrigerator in the path | route.

  Further, the transfer tube 404 is configured as a vacuum pipe in which a vacuum container and one end are connected, another vacuum container and the other end are connected, and at least a part of the reciprocating pipe is accommodated.

  Further, the bending holding structure mechanism is provided in a reciprocating pipe between the heat exchanger of the refrigerant circulation circuit in the vacuum vessel and the refrigerator, and is configured to be flexible in a two-dimensional direction or a three-dimensional direction. Further, the bending holding structure mechanism is provided in a reciprocating pipe between the heat exchanger 405 and the heat exchanger 414 of the refrigerant circulation circuit and the refrigerator, and is configured to be flexible in a two-dimensional direction or a three-dimensional direction.

  Further, the bending holding structure mechanism is provided in a reciprocating pipe between the heat exchanger 405, the heat exchanger 414, and the refrigerator, and is configured to be flexible in a two-dimensional direction or a three-dimensional direction.

  This realizes vibration isolation and cooling of the emitter tip 21. Gas field ionization ion source 1 is vibrated by sound waves generated from the operating sound of helium compressor 16 or compressor unit 399 as a compressor for sending helium to GM refrigerator 401, and the resolution of gas field ionization ion source 1 is improved. May deteriorate. Therefore, a device cover 423 that spatially separates the helium compressor 16 or the compressor unit 399 as a compressor and the field ion source 1 is preferably provided so as to cover the gas field ion source 1. This makes it possible to shield sound waves generated from the operating sound of the helium compressor 16 or the compressor unit 399 as a compressor, further reduce the influence of vibration, and enable a high resolution observation. And an ion microscope can be provided. In addition, in the embodiment using an apparatus that generates sound waves accompanying operating sound such as a compressor of the present specification, the same effect can be obtained if the apparatus cover 423 is provided so as to cover the gas field ion source 1 in the same manner. Can be obtained.

  In the case of the present embodiment, the second helium gas is circulated using the compressor unit 399. However, the flow rate adjusting valves are respectively provided from the pipe 101 and the pipe 102 of the helium compressor 16 without providing the compressor unit 399. The pipe 407 and the pipe 415 are connected to each other, and a circulating helium gas is supplied into the pipe 407 by using a part of the helium gas of the helium compressor 16 as a second helium gas. The pipe 415 supplies the gas to the helium compressor 16. Even if recovered, the same effect is produced. Even in this case, the cooling mechanism 100 is configured.

  FIG. 2 is a diagram illustrating a control device (or a control unit) that controls the ion microscope according to the first embodiment. This control device includes a gas field ion source control device 91 that controls the gas field ion source 1, a cooling mechanism control device 92 that controls the cooling mechanism 100, a lens control device 93 that controls the objective lens 8 and the like, a beam limiting aperture. 6, a beam limiting aperture control device 94 that controls the beam scanning electrode 7, an ion beam scanning control device 95 that controls the beam scanning electrode 7, a secondary electron detector control device 96 that controls the secondary particle detector 11, and a sample stage 10. A vacuum pump control device 98 for controlling vacuum pumps such as a sample stage control device 97, an ion source vacuum pump 12 and a sample chamber vacuum pump 13 and a calculation processing device 99 are configured. 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 unit, and the like.

  Here, the sample stage 10 includes a linear movement mechanism in two directions perpendicular to the sample placement surface, a linear movement mechanism in a direction perpendicular to the sample placement surface, a sample placement surface rotation mechanism, and a tilt axis. And a tilt function capable of changing the irradiation angle of the ion beam 14 onto the sample 9 by rotating the sample beam 14 to each other. These controls are performed by the sample stage control device 97 in response to a command from the calculation processing device 99.

  FIG. 3 is a diagram showing a schematic structural diagram of a gas field ion source in the ion microscope as the first embodiment. FIG. 4 is a schematic structural view of a gas field ion source including a refrigeration mechanism for cooling the emitter tip and the like of the gas field ion source as the first embodiment. In addition, this gas field ionization ion source 1 is comprised as a vacuum vessel. The emitter tip 21 is suspended from the upper flange 51. The emitter tip 21 can be adjusted in two horizontal right angles and in the vertical direction, and the movable tip can be adjusted in angle at the tip of the emitter tip 21. It has become. 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.

  In the present embodiment, preferably, the emitter tip 21 is made movable by a deformable mechanism component such as a highly flexible copper mesh wire 54 and is connected by a rigid mechanism component. Compared to the above, vibration transmission at high frequency is reduced. That is, the gas field ion source 1 using this cooling mechanism has a feature that the mechanical vibration of the emitter tip 21 can be further reduced. Further, from the viewpoint of reducing the vibration transmission from the refrigerator, the extraction electrode 24 has a fixed structure with respect to the vacuum vessel. Preferably, however, the sapphire base 55 that supports the extraction electrode 24 and the good heat conductor are cooled. The connection with the tip of the heat conductor 53 is preferably connected by a deformable copper mesh wire 56. Thereby, an ion microscope capable of high-resolution observation can be realized.

  Although not shown, the radiation shield is connected to the radiation shield 58 of FIG. 3 via a copper cooling heat conductor 406. The cooling heat conductor 406 is disposed up to the vicinity of the emitter tip 21 so as to cover the cooling heat conductor 53. The radiation shield 58 surrounds the gas molecule ionization chamber including the emitter tip 21 to reduce heat inflow due to thermal radiation into the gas molecule ionization chamber. Furthermore, the radiation shield 58 exists in the direction in which the ion beam 14 is drawn from the gas molecule ionization chamber, and is connected to at least one electrode of the electrostatic lens 59 facing the gas molecule ionization chamber. In the figure, the electrostatic lens 59 is composed of three electrodes, and the electrode 60 closest to the gas molecule ionization chamber is connected to the radiation shield 58 and cooled.

  FIG. 4 is a schematic diagram showing the vicinity of the emitter tip of the gas field ion source according to the first embodiment. The periphery of the emitter tip 21 of the gas field ion source 1 is constituted by an emitter tip 21, a filament 22, a filament mount 23, an extraction electrode 24, a gas supply pipe 25, a deformable bellows B62, and the like. The emitter tip 21 is fixed to the filament 22. The both ends of the filament 22 are fixed to the support rod 26 of the filament mount 23.

  The extraction electrode 24 is disposed 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 are configured to surround the emitter tip 21. A cylindrical radiant heat preventing laminated heat insulating material 30 is attached around the cylindrical side wall 28.

  Here, the gas molecule ionization chamber 15 is formed by the room surrounded by the extraction electrode 24, the side wall 28, and the top plate 29. A gas supply pipe 25 is connected to the gas molecule ionization chamber 15. Through this gas supply pipe 25, helium gas or hydrogen gas, which is an ionization gas, is supplied to the gas molecule ionization chamber 15. The ionized gas is controlled to a predetermined flow rate by the flow rate adjusting device 40 shown in FIG. The gas supply pipe 25 is brought into thermal contact with the cooling heat conductor 406 shown in FIG. 3, then brought into thermal contact with the cooling heat conductor 53, cooled to the temperature of the cooling heat conductor 53, and then gas molecule ionization chamber 15. Led in.

  The filament mount 23 is fixed to an emitter base mount 64, and the emitter base mount 64 is fixed to a vacuum vessel 61 via a bellows A61A that can be deformed.

Next, the operation of the gas field ion source 1 will be described.
In FIG. 4, after evacuation, the extraction electrode 24, the side wall 28, the top plate 29, and the like are heated to, for example, a temperature of 300 ° C. by the laminated heat insulating material 30 for preventing radiation heat provided outside the side wall 28 of the gas molecule ionization chamber 15. Bake and degas. At this time, the vacuum vessel 61 is also heated by another resistance heater disposed in the atmosphere at the same time, thereby baking and degassing, improving the degree of vacuum in the vacuum vessel 61 and lowering the residual gas concentration. By this operation, the time stability of the ion emission current can be improved.

  Here, in this embodiment, as shown in FIG. 1, the end 420 of the transfer tube 404 is hermetically isolated by a heat-resistant support rod 426 made of, for example, stainless steel, and a space in contact with both surfaces of the support rod 426 is formed. Isolated. The space on the gas field ion source 1 side during baking is the atmosphere, and is maintained at a baking temperature of 300 ° C. In this state, the temperature of the heat exchanger 405 and the heat exchanger 414 on the end 420 side rises via the cooling heat conductor 53 and the cooling heat conductor 406 facing the gas molecule ionization chamber 15. Since the components inside the transfer tube 404 are assembled by a coupling means such as welding or silver solder, they are not affected by baking. However, since the laminated heat insulating material 30 for preventing radiant heat disposed around these components is made of a material obtained by vapor-depositing aluminum on a thin polyester film, it is thermally decomposed at the baking temperature to maintain the heat insulating performance. I can't do it. For this reason, at the time of baking, the cooling mechanism 100 is operated under the control of the cooling mechanism control device 92, the cooling operation is performed, the temperature rise of the heat exchanger 405 and the heat exchanger 414 is suppressed, and the radiant heat prevention laminate The temperature of the heat insulating material 30 is cooled to 120 ° C. or lower. Thereby, the quality change of the laminated heat insulating material 30 for preventing radiant heat can be suppressed. Further, also in the cooling operation after baking, the gas molecule ionization chamber 15 can be quickly cooled to a predetermined low temperature.

  Thereafter, the heating of the gas molecule ionization chamber 15 and the vacuum vessel 61 is stopped, and after a sufficient time has elapsed, the cooling mechanism 100 is operated under the control of the cooling mechanism control device 92, and the emitter tip 21, the extraction electrode 24, and the radiation Cool the shield 58 and the like. Then, helium or hydrogen, which is an ionization gas, is introduced into the gas molecule ionization chamber 15 through the gas supply pipe 25. Here, preferably, when the small hole 27 of the extraction electrode 24 has a diameter of 0.2 mm or less, the gas pressure in the gas molecule ionization chamber 15 is at least 1 less than the degree of vacuum of the vacuum vessel 61 outside the gas molecule ionization chamber 15. It becomes possible to make it larger by an order of magnitude. Thereby, the rate at which the ion beam 14 collides with the gas in the vacuum and becomes neutral is reduced, and the ion beam 14 with a large current can be irradiated to the sample 9. Further, the number of high-temperature helium gas molecules colliding with the extraction electrode 24 is reduced, the cooling temperature of the emitter tip 21 and the extraction electrode 24 can be lowered, and the sample 9 can be irradiated with a large current ion beam 14.

  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 21. A lot of helium is pulled to the surface of the emitter tip 21 by the strong electric field and reaches the vicinity of the tip of the emitter tip 21 having the strongest electric field. Therefore, helium is ionized and the ion beam 14 is extracted through the small hole 27 of the extraction electrode 24. When the electric field intensity is adjusted here, helium ions are generated in the vicinity of one atom at the apex of the nanopyramid existing at the tip of the emitter tip 21. Is generated. That is, since ions are generated in a very limited region, the current emitted from the unit area and the 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 the sample 9.

  Next, in FIG. 3, the ion beam 14 that has passed through the lens passes through the scanning deflection electrode 301, 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 the movable shutter 303 while scanning the ion beam 14 are detected by the secondary particle detector 305 to obtain a secondary particle image, the ion emission of the emitter tip 21 is obtained. A pattern can be observed. Therefore, the position and angle of the emitter tip 21 are adjusted while observing the ion radiation pattern. Further, the trajectory of the ion beam 14 or the position of the aperture plate 302 can be adjusted so that the ion beam 14 from one atom passes through the aperture plate 302 from the ion radiation pattern. When the tip of the pyramid is composed of 3 or 6 atoms, the trajectory of the ion beam 14 is selected so that ions emitted from the vicinity of any one of the atoms are selected and passed through the aperture plate 302. Alternatively, the position of the aperture plate 302 can be adjusted. The same effect can be obtained even if secondary particles such as secondary electrons emitted from the aperture plate 302 are detected by the secondary particle detector 305 to obtain secondary particle images. In particular, if a fine protrusion is provided on the movable shutter 303 and this secondary particle image is observed, the pattern can be observed more clearly. Then, after this adjustment, the shutter 303 is moved to pass the ion beam 14.

  In the gas field ionization ion source 1, since the gas molecule ionization chamber 15 is highly airtight and the degree of vacuum is high outside the gas molecule ionization chamber 15, the ion beam 14 collides with gas in the vacuum and becomes neutralized. The sample 9 can be irradiated with a large current ion beam 14. Further, the number of high-temperature helium gas molecules colliding with the extraction electrode 24 is reduced, the cooling temperature of the emitter tip 21 and the extraction electrode 24 can be lowered, and the sample 9 can be irradiated with a large current ion beam 14.

  When the nanopyramid is damaged due to an unexpected discharge phenomenon or the like, the nanopyramid can be easily regenerated by heating the emitter tip 21 for about 30 minutes (about 1000 ° C.). If the damage cannot be repaired, replace the emitter tip 21 with a normal one.

  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 21 of the gas field ion source 1 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 dot beam can be obtained on the sample 9. 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 14 is scanned by the ion beam scanning electrode 7 so that it is detected by the secondary particle detector 11 such as secondary electrons emitted from the sample 9, and this is subjected to luminance modulation to thereby calculate the calculation processor 99. A scanning ion microscope image can be obtained on the image display means. That is, high-resolution observation of the surface of the sample 9 is realized.

  Here, in the gas field ion source 1 in this embodiment, it is preferable to use ions emitted from the vicinity of one atom at the tip of the nanopyramid. That is, the area | region where ion is discharge | released is narrow, and an ion light source is small below nanometer. For this reason, when the ion light source is focused on the sample 9 at the same magnification or the reduction ratio is increased to about one half, the characteristics of the gas field ion source 1 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 or less on the sample 9, it is necessary to reduce the reduction ratio to 1/10 or less. . In this case, the oscillation of the emitter tip of the ion source is reduced to 1/10 or less on the sample 9. For example, even if the emitter tip 21 vibrates by 10 nm, it is 1 nm or less on the sample 9 and the influence 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 9 at a reduction ratio of 1/2, and becomes large with respect to the beam diameter. Therefore, the conventional apparatus is not sufficiently considered in this respect, and good sample surface observation has not always been realized. In the present embodiment, since measures against this vibration are sufficient, the performance of the ion source can be sufficiently exerted, and high-resolution observation of the sample surface can be realized.

  The distance between the tip of the objective lens 8 and the surface of the sample 9 is referred to as a work distance. Preferably, if this is shortened to less than 2 mm, an ultrahigh resolution of less than 0.5 nm can be realized. Conventionally, since ions such as gallium were used, there was a concern that sputtered particles from the sample contaminated the objective lens and hindered normal operation. Resolution can be realized.

  Although the extraction electrode 24 of the gas field ion source 1 in this embodiment is fixed to the vacuum vessel, the emitter tip 21 is connected to the vacuum tip by connecting the emitter tip mount 64 with a copper mesh wire. 24 is movable. This makes it possible to adjust the position of the emitter tip 21 with respect to the small hole 27 of the extraction electrode 24 and the axis of the optical system, thereby forming a finer beam.

Further, when the vacuum sample chamber and the pump for evacuating the sample chamber can be heated to about 200 ° C. and the vacuum degree of the sample chamber can be reduced to 10 ⁻⁷ Pa or less at the maximum, the sample was irradiated with an ion beam. Sometimes the contamination does not occur so much and the sample surface can be observed well. Compared with a conventional SEM, the growth of contamination deposition by irradiation with a helium or hydrogen ion beam is fast, and it is sometimes difficult to observe the sample surface. Therefore, if the vacuum sample chamber and the sample chamber evacuation pump are heat-treated in a vacuum state, the residual hydrocarbon gas in the sample chamber vacuum can be reduced, and the outermost surface of the sample can be observed with high resolution. it can.

Here, a turbo molecular pump, a sublimation pump, a non-evaporable getter pump, an ion pump, a noble pump, or the like can be used as the sample chamber vacuum pump. In particular, when any one of a sublimation pump, a non-evaporable getter pump, an ion pump, a noble pump or an Excel pump is used as a main vacuum pump, an ultrahigh vacuum of 10 ⁻⁷ Pa or less can be obtained relatively easily. The outermost surface of the sample can be observed with high resolution with little influence of vibration. Even if the turbo molecular pump is operating at this time, the same effect can be obtained if the main vacuum pump is a sublimation pump, a non-evaporable getter pump, an ion pump, a noble pump or an Excel pump.

  In addition, as shown in FIG. 1, the same effect can be obtained even if the leg of the device base 17 that supports the base plate 18 is provided with a vibration isolation mechanism 19.

  As described above, according to the present embodiment, at least one of the following effects is achieved.

  1) Due to the bending holding structure of the bending holding structure mechanism 500, in the coiled piping 501 having the Y axis in the drawing in the vertical direction upward in the plane of the drawing, the copper piping is subjected to conditioning treatment and is very It is soft and has a bending that absorbs vibration in the Y-axis direction of the piping 403 of the refrigerant circuit. Also, in the coiled pipe 502 having the X axis in the drawing in the horizontal direction in the drawing, the copper pipe is similarly softened and absorbs the vibration of the pipe 403 in the X axis direction. It has the bending to do. Therefore, the vibration in the XY-axis direction in the vacuum heat insulating container 416 of the pipe 403 that is fixedly supported by the fixed support 418 indirectly by the fixed support 504 is sufficiently absorbed in the pipe 403 and passes through the fixed support 504. The vibration to the pipe 403 in the transfer tube 404 hardly propagates. Therefore, it is possible to provide a cooling device that suppresses transmission of vibration to an object to be cooled, an ion microscope, an observation device, or an inspection device using the cooling device.

  2) By the bending holding structure mechanism 500 and the bending holding structure mechanism 508, vibrations in the XY axial directions of the refrigerant circulation circuit pipes 407, 413, and 415 in the vacuum heat insulating container 416 are also caused by the coiled pipe 506 and the coiled pipe 507. The vibration to the pipe 407, the pipe 413, and the pipe 415 in the transfer tube 404 after being absorbed by the coiled pipe 509, the coiled pipe 510, the coiled pipe 511, and the coiled pipe 512 and penetrating the fixed support 504 is Hardly propagates. Therefore, it is possible to provide a cooling device that suppresses transmission of vibration to an object to be cooled, an ion microscope, an observation device, or an inspection device using the cooling device.

  3) The vibration of the helium compressor 16 or the compressor unit 399 as a compressor or the GM refrigerator 401 causes the pipe 400, the pipe 403, the pipe 407, the pipe 413, and the pipe 415 of the refrigerant circulation circuit to vibrate. By providing at least one of the bending holding structure mechanism 500 and the bending holding structure mechanism 508, this vibration can be absorbed. Therefore, it is possible to provide a cooling device that suppresses transmission of vibration to an object to be cooled, an ion microscope, an observation device, or an inspection device using the cooling device.

  4) The gas field ion source 1, the ion beam irradiation system column 2, the vacuum sample chamber 3 and the like as the objects to be cooled are isolated from the helium compressor 16 or the compressor unit 399 as the compressor and the GM refrigerator 401. Further, the pipe 403, pipe 407, pipe 413, and pipe 415 in the transfer tube 404 connected to the heat exchanger 405 and the heat exchanger 414 installed in the vicinity of the gas field ion source 1 hardly vibrate. Since the base plate 18 is firmly fixed and supported, vibration is suppressed, and transmission of mechanical vibration is extremely small. Therefore, it is possible to provide a cooling device that suppresses transmission of vibration to an object to be cooled, an ion microscope, an observation device, or an inspection device using the cooling device.

  5) The bending holding structure mechanism in the refrigerant circuit is configured by winding a straight pipe into a coil shape, and is not configured by connecting straight pipes with a bellows. Therefore, when a high-pressure fluid flows in the pipe, the bellows pipe is extended by the internal pressure, and a support member that restrains the bellows pipe is necessary at both ends of the bellows pipe, and vibration is propagated between the both ends of the bellows pipe through this support member. However, since the pipe is constituted by a straight pipe, the pipe hardly extends even when a high-pressure fluid flows in the pipe, and a support member is not required. Therefore, vibrations in the refrigerant circuit can be sufficiently reduced even when high-pressure fluid flows. Therefore, it is possible to provide a cooling device that suppresses transmission of vibration to an object to be cooled, an ion microscope, an observation device, or an inspection device using the cooling device.

  6) A base plate 18 is disposed on the apparatus base 17, and the gas field ion source 1, ion beam irradiation system column 2, vacuum sample chamber 3, etc. are fixed to the base plate 18. A vibration isolation mechanism 19 is disposed between the apparatus base 17 and the base plate 18, and high-frequency vibration of the floor is transmitted to the gas field ion source 1, the ion beam irradiation system column 2, the vacuum sample chamber 3, and the like. Can be difficult.

  7) It is possible to provide a gas field ion source and an ion microscope capable of reducing mechanical vibration and enabling high-resolution observation.

8) In an ion microscope using a field ion source, if a large current density ion beam is 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 angle current density of the field ion source, the better. In order to increase the ion radiation angle current density, the emitter tip is cooled to a very low temperature, and the ion material gas pressure around the emitter tip is increased to about 10 ⁻² to 10 Pa. However, when the ion material gas pressure is increased to 1 Pa or more, the ion beam collides with the neutral gas and is neutralized, so that the ion current decreases.

  In addition, when the number of gas molecules in the field ion source increases, the temperature of the emitter tip increases as the gas molecules collided with the vacuum vessel wall, which is hotter than the emitter tip, collide with the emitter tip. This raises the problem that the ion current decreases.

  Therefore, it is conceivable to provide a structure that mechanically surrounds the periphery of the emitter tip, that is, a gas ionization chamber having an ion extraction electrode or the like as a wall so that cryogenic gas molecules are supplied only to the periphery of the emitter tip. In this case, the gas ionization chamber and the emitter tip are fixed.

  However, in an emitter tip having a nanopyramid structure provided with a minute protrusion at the tip, the spread of the angle at which the ion beam is emitted is only about 1 degree. Therefore, it is necessary to direct the ion beam toward the sample. At this time, when the emitter tip is tilted by mechanically adjusting the direction of the emitter tip, the direction of the extraction electrode is also tilted because the gas ionization chamber is a fixed structure. This slight inclination of the extraction electrode affects the focusing performance of the ion beam. That is, the resolution of sample observation deteriorates. Moreover, in an ion microscope equipped with a gas field ion source, many emitter tip cooling means include a factor that generates mechanical vibration such as a mechanical refrigerator, which tends to cause emitter tip vibration. When the emitter tip vibrates, there arises a problem that the ion beam is shaken and the resolution of sample observation is deteriorated. However, according to the present embodiment, it is possible to provide an ion microscope that reduces the mechanical vibration of the emitter tip and enables high-resolution sample observation.

  9) When it is necessary to direct the ion beam in the direction of the sample, the direction of the emitter tip is mechanically adjusted to tilt the emitter tip. However, when the gas ionization chamber has a movable structure, the cooling mechanism is a gas ionization chamber. When the cooling mechanism is heavy, it is difficult to mechanically adjust the direction of the emitter tip, and the resolution of sample observation deteriorates. According to the present embodiment, the direction of the emitter tip can be easily adjusted, and both the improvement of the ion source luminance by low vibration cooling of the emitter tip and the improvement of the ion beam focusing performance by the adjustment of the direction of the emitter tip are achieved. Can be provided.

  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 gas molecule density per unit pressure is inversely proportional to the gas temperature, and it is important to cool the gas including the emitter tip. However, when cooling the gas molecule ionization chamber containing gas molecules from the cold head of the refrigerator where the temperature falls most by the heat conduction through the good thermal conductor that is a cold finger, the temperature drop occurs when the cold finger becomes longer. The gas molecule ionization chamber and the emitter tip built in the gas molecule ionization chamber cannot be cooled to a cryogenic temperature. According to this embodiment, the cryogenic temperature of the gas molecule ionization chamber and the emitter tip can be realized.

  10) If the operation is continued in the gas field ion source, impurity molecules in the apparatus accumulate at the tip of the emitter tip, and a large amount of ion current cannot be obtained. Therefore, in order to periodically replace with a new emitter tip, the inside of the apparatus is heated to room temperature and then released to atmospheric pressure. At this time, since impurities in the atmosphere enter the apparatus, it is necessary to bake the apparatus including the emitter tip and a part of the cooling mechanism for cooling the emitter tip at a high temperature of about 300 ° C. However, the cooling mechanism often uses a member with poor heat resistance, such as a mylar in a radiant heat reflecting sheet for heat insulation, which changes its heat during baking, deteriorates the heat insulation performance, and lowers the cooling performance. As a result, the cryogenic temperature of the emitter tip cannot be achieved. According to this embodiment, deterioration of the heat resistance of the cooling mechanism during baking can be suppressed.

  11) The time required to freeze the emitter tip to a cryogenic temperature often increases as the mass of the cooling mechanism and the member that must be cooled increases. In addition, as a refrigerator that constitutes a part of the cooling mechanism, a small-sized and low-output refrigerator is often selected in order to reduce operating vibration. Therefore, it takes a long time to cool the apparatus, the start-up time of the apparatus becomes long, and the operation rate of the apparatus decreases. According to the present embodiment, the emitter tip cooling time can be shortened.

  12) To provide a gas electroionization ion source that realizes reduction of mechanical vibration and improves both ion source brightness and ion beam focusing performance, and an ion microscope, observation apparatus, or inspection apparatus capable of high-resolution observation. be able to.

  13) It is possible to provide a gas electrolytic ion source capable of achieving a cryogenic temperature of the emitter tip and obtaining a high-current ion beam, and an ion microscope, an observation device, or an inspection device capable of high-resolution observation.

  14) A cross-section is formed by processing a sample with an ion beam as a combined device of an ion microscope and an ion beam processing apparatus capable of high-resolution observation, and this cross-section is observed with an ion microscope, or resolution observation is possible A combined device of ion microscope and electron microscope, cross-section observation method using these devices can be provided, and sample observation with ion microscope, sample observation with electron microscope and elemental analysis can be performed with one device In addition, it is possible to provide an analysis apparatus and an inspection apparatus for observing and analyzing defects and foreign matters.

  In the present embodiment, the bending holding structure mechanism that mainly absorbs vibrations in the biaxial directions of the XY axes has been described, but further, a coil shape having a winding direction in a direction perpendicular to the drawing sheet (not shown). If a pipe is additionally provided, it is possible to provide a bending holding structure mechanism that can mainly absorb vibrations in the three axial directions of the XYZ axes.

  Here, it is preferable that the support rod 426 has a honeycomb structure with a long heat transfer distance in order to prevent intrusion heat from room temperature.

  In the present embodiment, the GM type refrigerator 401 is used for the cooling mechanism 100. However, a pulse tube refrigerator, a Stirling refrigerator, an electronic refrigerator, and an expansion turbine refrigerator are used as the refrigerator. Even if used, the same effect is produced.

  FIG. 5 is a diagram showing a schematic configuration diagram of a bending holding structure mechanism 512A used in the ion microscope as the second embodiment. In the present embodiment, unlike the bending holding structure mechanism 500 of FIG. 1, instead of the pipe-shaped pipe 501 having an axis of the winding direction in the vertical direction upward in the plane of the paper, the piping is serpentine meandered as a bending holding structure. It is the point comprised by the meandering pipe line 513 which formed the U-shaped curve like a body shape continuously, and others are the same. This copper pipe is subjected to conditioning treatment heated at a high temperature after bending, and is very soft. By forming the pipe in a meandering body in this way, the bending can mainly absorb minute displacements in the Y direction in the figure. It is the structure which has. Similarly, the meandering pipe 514 has a structure capable of absorbing a small displacement mainly in the X direction in the figure. With this structure, it is possible to absorb vibrations in the XY axis directions of the piping 403 of the refrigerant circuit. Similarly, the meandering pipes 515 and 516 of the flexure holding structure mechanism 512A can absorb vibrations in the XY-axis direction of the pipe 407 of the refrigerant circulation circuit, thereby preventing the vibration of the gas field ion source 1 to be clear. There is an effect that can obtain a clear image. Similarly, the bending holding structure mechanism 508 can have the same form. In addition, although the bending holding structure mechanism that mainly absorbs the vibration in the biaxial directions of the XY axes has been described, a coiled pipe having a winding direction in the vertical direction (Z axis direction not shown) is additionally provided. By doing so, it is possible to provide a bending holding structure mechanism that can mainly absorb vibrations in the three axial directions of the XYZ axes.

  FIG. 6 is a diagram showing a schematic configuration around the cooling mechanism of the ion microscope as the third embodiment.

  The connection portion between the inlet flange 503 of the transfer tube 404 used in the ion microscope as the third embodiment and the vacuum heat insulating container 416 is constituted by a magnetic fluid seal ring 518 integrated with the upper flange 517 of the vacuum heat insulating container 416. Between the inlet flange 503 and the magnetic fluid seal ring 518, a doughnut-shaped magnetic fluid 520 held by the magnetic force of the magnet 519 in the magnetic fluid seal ring 518 maintains a vacuum airtightness. Since the magnetic fluid 520 is liquid, it is possible to prevent vibration such as mechanical vibration of the refrigerator on the vacuum container side from propagating to the inlet flange 503 side. The inlet flange 503 receives pressure on the vacuum vessel side at atmospheric pressure, but is fixedly supported by a fixed support 419.

  According to this embodiment, compared with the bellows tube 505 of FIG. 1, the bellows tube has a small effect of preventing the propagation of vibrations in the radial direction of the bellows tube 505, but the magnetic fluid 520 is in a liquid state. Since the vibration of the transfer tube 404 is clearly reduced, the vibration of the gas field ion source 1 can be prevented, and a clearer image can be obtained.

DESCRIPTION OF SYMBOLS 1 Gas field ionization ion source 2 Ion beam irradiation system column 3 Vacuum sample chamber 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 exhaust pump 14 Ion beam 15 Gas molecule ionization chamber 16 Helium compressor 17 Device base 18 Base plate 19 Vibration isolation mechanism 21 Emitter tip 22 Filament 23 Filament mount 24 Extraction electrode 25 Gas supply pipe 26 Support rod 27 Small hole 28 Side wall 29 Top plate 30 Laminated heat insulating material 51 for preventing radiation heat Upper flanges 52, 55 Sapphire bases 53, 406 Cooling heat conductors 54, 56 Copper wire 60 Electrode 61 Vacuum vessel 92 Cooling mechanism controller 93 Lens controller 94 Beam limiting aperture controller Device 95 Ion beam scanning control device 96 Secondary electron detector control device 97 Sample stage control device 98 Vacuum pump control device 99 Calculation processing device 399 Compressor unit 401 GM type refrigerators 402, 405, 410 Heat exchanger 403, 407, 413, 415 Piping 404 Transfer tube 419, 504 Fixed support body 426 Support rod 500, 508 Deflection holding structure mechanism 501, 502, 506, 507, 509, 510, 511, 512 Coiled piping 503 Inlet flange 505 Bellow pipe 518 Magnetic fluid seal ring 519 Magnet 520 Magnetic fluid

Claims (8)

A cooling heat conductor thermally coupled to an object to be cooled stored in the first vacuum vessel, at least a part of which is cooled to a temperature lower than room temperature;
A heat exchanger thermally coupled to the cooling heat conductor;
A reciprocating pipe for supplying a refrigerant having a temperature lower than room temperature for cooling the object to be cooled to the heat exchanger and collecting the refrigerant from the heat exchanger, and a refrigerator for cooling the refrigerant. A refrigerant circulation circuit,
A second vacuum container for storing at least a part of the reciprocating pipe and the refrigerator;
The first vacuum vessel and one end are connected, the second vacuum vessel and the other end are connected, and a vacuum pipe that houses at least a part of the reciprocating pipe;
A bending holding structure mechanism provided in the reciprocating pipe between the heat exchanger of the refrigerant circulation circuit in the second vacuum vessel and the refrigerator, and flexible in a two-dimensional direction or a three-dimensional direction. Cooling system. A cooling heat conductor that is housed in a vacuum vessel and that is thermally connected to the object to be cooled, at least a part of which is cooled to a temperature lower than room temperature, and the cooling heat conductor A heat exchanger that is thermally coupled to and directly or indirectly mechanically coupled to the vacuum vessel;
A refrigerant having a temperature lower than room temperature for cooling at least the object to be cooled is supplied to the heat exchanger, and a reciprocating pipe for collecting the refrigerant from the heat exchanger and a refrigerator for cooling the refrigerant are used as paths. A refrigerant circulation circuit having,
A cooling apparatus comprising: a bending holding structure mechanism provided in the reciprocating pipe between the heat exchanger and the refrigerator of the refrigerant circulation circuit and flexible in a two-dimensional direction or a three-dimensional direction. A heat exchanger that is directly or indirectly mechanically connected to the object to be cooled and cools at least a part of the object to be cooled directly or indirectly;
A reciprocating pipe for supplying and recovering refrigerant to the heat exchanger;
A refrigerator for cooling the refrigerant;
A cooling apparatus comprising: a bending holding structure mechanism provided in the reciprocating pipe between the heat exchanger and the refrigerator, and flexible in a two-dimensional direction or a three-dimensional direction.   The cooling device according to any one of claims 1 to 3, wherein the bending holding structure mechanism is configured by two or more coiled pipes.   The said bending holding | maintenance structure mechanism is comprised by the pipe line which formed the U-shaped curve continuously in the meandering form in the two-dimensional direction or the three-dimensional direction, respectively. Low vibration cooling device. The vacuum vessel and one end of the vacuum pipe are:
The cooling device according to claim 1, wherein the cooling device is connected by a magnetic fluid seal ring.   An ion microscope comprising the cooling device according to any one of claims 1 to 3, wherein the object to be cooled is composed of at least an emitter tip.   An observation device or an inspection device comprising the cooling device according to any one of claims 1 to 3.

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