JP2000121713A - Low temperature specimen position control equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of position precision due to vibration, when a specimen is measured or observed at a low temperature by using a sensor like an SQUID. SOLUTION: This control equipment is provided with a specimen stand 29 holding a specimen, a sensor stand 61 which faces the specimen of the specimen stand 29 and hold a sensor, a cooling head 35 for a specimen which cools the specimen at a low temperature, a cooling head 59 for a sensor for cooling the sensor, a specimen side thermal shield cabinet 27 for thermally shielding the specimen stand 29 and the cooling head 35 for a specimen, a sensor side thermal shield cabinet 57 for thermally shielding the sensor stand 61 and the cooling head 59 for a sensor, and a position control means 19 for position- controlling the specimen stand 29 in the three-dimensional direction. The cooling head 35 for a specimen and the specimen stand 29 are separately arranged in the specimen side thermal shield cabinet 27. The cooling head 35 for a specimen is coupled with the specimen stand 29 by using thermal conduction part member 41 having flexibility.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample made of various elements and materials, such as various semiconductor elements and semiconductor materials, a superconducting material, a metal material and an inorganic material, at a cryogenic temperature of about several K, such as a SQUID. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the position of a sample with respect to a sensor in a three-dimensional direction with a minute precision of a micron unit when performing measurement and observation with a sensor.

[0002]

2. Description of the Related Art Recently, a high-sensitivity magnetometer called a SQUID (superconducting quantum interferometer) has been put into practical use, and measurement using SQUIDs for various elements and materials has been increasing. Since SQUID uses superconductivity, it needs to be cooled to a very low temperature of about liquid helium temperature (about several K), and the other party's sample needs to be kept at a very low temperature or a temperature close to it. Often. In addition to the SQUID, when a sample is observed with a tunnel microscope, the tunnel microscope may be kept at a very low temperature, and the counterpart sample may need to be kept at a very low temperature or a low temperature close thereto. .

With the spread of measurement and observation at extremely low temperatures using SQUIDs and the like, it is necessary to control the position of a sample such as a SQUID or a tunnel microscope by minutely moving the sample in a three-dimensional direction with high precision on the order of microns. In particular, when performing measurement or observation while scanning, high-precision position control is required.
However, conventionally, a device for controlling a micro-position in a three-dimensional direction with high accuracy in units of microns while cooling and holding a sensor or a sample at an extremely low temperature has not been put to practical use yet.

[0004]

SUMMARY OF THE INVENTION The present inventors diligently develop a device for controlling the position of a sample relative to a sensor in a three-dimensional direction with high precision on the order of microns while maintaining the sensor and the sample at a very low temperature. After conducting experiments and examinations,
In the process, the following problems were found.

That is, it is considered that this type of device basically needs to move and control the sample by the three-dimensional position control means while cooling the sensor and the sample with a cooling medium such as liquid helium. However, when a sample or sensor is cooled to an extremely low temperature by introducing a cooling medium such as liquid helium from the outside, the vibration caused by the introduction and discharge of the cooling medium, especially the vibration of the cooling medium introduction pipe and the cooling medium discharge pipe, is transmitted to the sample. In many cases, the positional accuracy of the sample is reduced, and accurate measurement and observation are difficult, resulting in a large measurement error. As a means for controlling the position in the three-dimensional direction with high accuracy, it is conceivable to use a piezoelectric element (piezo element). However, the piezoelectric element is vulnerable to mechanical stress, and the introduction and discharge of the cooling medium as described above. If vibration is applied to the piezoelectric element, the piezoelectric element may be broken. Of course, if the sample is firmly fixed by a rigid support member, it is possible to prevent the vibration caused by the introduction and discharge of the cooling medium from adversely affecting the sample. When a sample is firmly fixed with a member, the heat penetration from the support member into the sample usually becomes large, which lowers the cooling efficiency and makes it difficult to keep the sample at extremely low temperatures. Also, new problems such as a remarkable increase in the consumption of the cooling medium occur. In addition, there are various obstacles in realizing high-precision position control at extremely low temperatures as described above.

The present invention has been made in view of the above circumstances, and basically provides an apparatus capable of controlling the position of a sample with respect to a sensor with high precision on the order of microns while cooling the sample and the sensor to a low temperature. In that case, the vibration due to the introduction and discharge of the cooling medium is not affected on the sample without lowering the cooling efficiency, and the fine position control is also performed. Therefore, even when an element that is weak to mechanical stress such as a piezoelectric element is used, it is an object of the present invention to be able to effectively prevent the element from being broken by the mechanical stress due to the aforementioned vibration. .

[0007]

In order to solve the above-mentioned problems, a cryogenic sample position control apparatus according to the present invention basically comprises a cooling head for cooling a sample and a sample holding the sample. The table is structurally separated from the table, and the space between them is connected by a flexible heat conductive member, and the sample is kept at a very low temperature without affecting mechanical stress such as vibration from the cooling head on the sample side. I was able to do it.

Specifically, the low-temperature sample position control device according to the first aspect of the present invention includes a sample stage for holding a sample, a sensor stage for holding a sensor in opposition to the sample on the sample stage, and a low-temperature sample. A sample cooling head for cooling, a sensor cooling head for cooling the sensor, a sample side heat shield housing for thermally shielding the sample stage and the sample cooling head, the sensor stage and the sensor A sensor-side heat shield housing for heat shielding the cooling head for use, and position control means for controlling the position of the sample stage in a three-dimensional direction, wherein the sample cooling head and the sensor cooling head are respectively A cooling medium for inflow and outflow from the outside, and the sample cooling head and the sample stage are arranged separately from each other in a sample-side heat shield housing; and The cooling head and the sample stage are connected by a flexible heat conductive member, and the sample stage and the sample are configured to be cooled to a low temperature via the flexible heat conductive member. It is characterized by the following.

In the present invention, the term "sensor" means not only a sensor for measuring physical properties and characteristics of a sample, a magnetic flux generated from the sample and various radiations, but also a device for observing the surface condition of the sample, such as a tunnel microscope. Shall also be included.

According to a second aspect of the present invention, there is provided the low-temperature sample position control apparatus according to the first aspect, wherein the position control means performs position control in a three-dimensional direction with a relatively large moving amount. A position control mechanism; a movable table whose position is controlled by the first position control mechanism to move; and a movable table interposed between the movable table and the sample table with a relatively small amount of movement.
A second position control mechanism for performing position control in the dimensional direction, wherein the sample cooling head is attached to the movable table via a heat-insulating support member.

According to a third aspect of the present invention, there is provided a low-temperature sample position control apparatus according to the second aspect, wherein the second position control mechanism comprises a piezoelectric element, and is provided between the piezoelectric element and the sample stage. An intermediate connecting member having heat insulating property is interposed in the second member.

According to a fourth aspect of the present invention, there is provided the low-temperature sample position control apparatus according to the third aspect, wherein the sample-side heat shield housing is fixed to the support member, and the sample stage is connected to the sample side. It is arranged in the sample-side heat shield case so as not to be in contact with the heat shield case.

According to a fifth aspect of the present invention, there is provided a low-temperature sample position control apparatus according to the first aspect, wherein the magnetic shield surrounds at least the entirety of the sensor stage, the sensor cooling head, the sample stage, and the sample cooling head. Is provided.

Further, the low-temperature sample position control apparatus according to the invention of claim 6 is arranged such that three
A first position control mechanism for performing position control with a relatively large amount of movement in the dimensional direction, a movable table whose position is controlled by the first position control mechanism, and a support member having heat insulation properties on the movable table. A sample-side heat shield case mounted and mounted, and a sample fixed via a heat-insulating cooling head base in the sample-side heat shield case and configured so that a cooling medium is introduced and discharged from outside. Cooling head, a sample stage provided in the sample-side heat shield housing in a non-contact state with respect to the housing and separated from the sample cooling head, and attached to the movable stage. A second position control mechanism for controlling the position of the sample stage with a relatively small amount of movement in a three-dimensional direction; and a heat conducting member having flexibility connecting the sample cooling head and the sample stage. When,
A sensor base facing the sample base, a sensor cooling head for cooling the sensor base by introducing and discharging a cooling medium from the outside, and a sensor side heat source surrounding the sensor base and the sensor cooling head. A sensor-side heat shield housing provided separately from the shield housing, and a sensor-side support member for supporting the sensor base, the sensor cooling head, and the sensor-side heat shield housing to fix their positions. It is characterized by being provided.

According to a seventh aspect of the present invention, there is provided the low-temperature sample position control apparatus according to the sixth aspect, wherein the second position control mechanism comprises a piezoelectric element, and the second position control mechanism is provided between the piezoelectric element and the sample stage. An intermediate connecting member having heat insulating property is interposed between them.

According to an eighth aspect of the present invention, there is provided the low-temperature sample position control apparatus according to the sixth aspect, wherein at least the sensor stage, the sensor cooling head, the sample stage, and the sample cooling head in the chamber. A magnetic shield is provided in a portion surrounding the magnetic shield.

According to a ninth aspect of the present invention, there is provided the low-temperature sample position control apparatus according to the eighth aspect, for supplying a cooling medium to the sample cooling head and the sensor cooling head outside the chamber. A cooling medium supply device is provided, the cooling medium supply device has at least a double structure including an outer container and an inner container, and is configured to store the cooling medium in the inner container. The inner container and the outer container are configured to be able to maintain a vacuum, and the vacuum part and the space part of the chamber that is maintained in a vacuum are hermetically isolated. It is.

According to a tenth aspect of the present invention, there is provided the low-temperature sample position control apparatus according to the ninth aspect, wherein: from the inner container of the cooling medium supply device to the sample cooling head and the sensor cooling head in the chamber. Flow rate control means and temperature control means for controlling the flow rate and temperature of the supplied cooling medium are provided in the cooling medium supply device.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

[0020]

FIG. 1 shows an entire configuration of an example of a low-temperature sample position control apparatus according to the present invention. FIG. 2 shows an enlarged view of a main part of an example of the low-temperature sample position control apparatus.

In FIG. 1 and FIG. 2, the chamber 1 has a box shape or a cylindrical shape as a whole by vertically combining a chamber upper body 1A having an open lower surface and a chamber lower body 1B having an open upper surface. Was made as
The inside thereof is configured to be sucked and held in vacuum by a vacuum pump not disclosed. Optical windows 3 and 5 for visually observing the sample position from the outside are provided on the upper side surface and upper surface of the chamber 1, and a cooling medium supply / reflux is provided on the lower side surface side of the chamber 1. An opening 13 is formed to protrude. The opening 13 has two cooling medium supply pipes 9A and 9B for introducing liquid helium as a cooling medium from a cooling medium supply device 7 described later, and cooling heads 35 and 59 described later. Discharge pipes 11A and 11B for returning the vaporized helium gas to the cooling medium supply device 7 are inserted from the cooling medium supply device 7 side. Further, inside the chamber upper body 1A and the chamber lower body 1B of the chamber 1, magnetic shields 15A and 15B for inner surfaces made of a magnetic material having high magnetic permeability are arranged along inner wall surfaces thereof. On the other hand, the upper and lower partitioning magnetic shields 15 are arranged at the boundary positions between the upper chamber body 1A and the lower chamber body 1B in the chamber 1 so as to partition the space in the chamber 1 up and down.
C is provided horizontally.

A base plate 17 is fixed to the bottom of the chamber 1 (the bottom inside the inner surface magnetic shields 15A and 15B). And this base plate 1
7 has an X-axis direction driving device 19 such as a pulse motor.
A, Y-axis direction driving device 19B, Z-axis direction driving device 19C
Are provided in the first position control mechanism 19. The first position control mechanism 19 is for moving the upper movable table 21 in the three-dimensional direction to roughly control the position of the sample table 29 in the three-dimensional direction described later with a relatively large moving amount. It is.

On one side of the movable table 21, a columnar piezoelectric element is provided as a second position control mechanism for finely controlling the position of the sample table 29 in the three-dimensional direction with a relatively small movement amount. 23 are provided vertically. The piezoelectric element 2
At the upper end of 3, a rod-shaped intermediate connecting member 25 made of a material having a heat insulating effect such as FRP is provided vertically, and the upper end portion of the intermediate connecting member 25 is placed in a sample-side heat shield housing 27 described later. A sample table 29 made of a good heat conductive material such as copper is provided at the upper end of the intermediate connecting member 25 in the heat shield case 27, which is inserted through an opening 27A at the bottom of the heat shield case 27. . This sample table 29
Is configured to hold a sample such as various elements or materials to be measured or observed on the upper surface.

On the other side of the movable table 21, an FRP
A columnar support member 31 made of a material having a heat insulating effect, such as, is vertically provided. The sample-side heat shield case 27 is fixed to the upper end of the support member 31. The extension of the support member 31 in the sample-side heat shield case 27 has a heat insulating effect such as FRP. A cooling head base 33 made of a material having the same is provided. A sample cooling head 35 is provided on the cooling head base 33. The sample cooling head 35 is made of a good heat conductive material such as copper into a hollow tank shape, and liquid helium as a cooling medium is introduced from a lower part through a cooling medium introduction pipe 37, and The helium gas obtained by vaporizing the liquid helium is discharged through a discharge pipe 39. The sample cooling head 35 and the sample table 29 are connected by a heat conductive member 41 having flexibility, for example, a copper braid formed by braiding a copper wire. The flexible heat conductive member 41 has a sufficient length so as to always maintain a bent state, that is, not to be in a tension state.

Further, the sample table 29 and the intermediate connecting member 25 supporting the sample table are kept in a non-contact state with respect to the sample-side heat shield case 27. Therefore, in order to insert the intermediate connecting member 25, the sample-side heat shield housing 2
The opening 27 </ b> A formed on the bottom surface of 7 is determined so that its inner diameter is sufficiently larger than the outer diameter of the intermediate connecting member 25. On the upper surface of the sample-side heat shield case 27,
An opening 27B is formed at a position facing the upper surface of the sample table 29. Further, an opening 27C for confirming a sample position is formed on a side surface of the sample-side heat shield housing 27 closer to the sample stage 29 (a position corresponding to the optical window 3 on the side surface of the chamber 1). , This opening 27C
A radiation shield pipe 43 extends toward the optical window 3. The radiation shield pipe 43 has an inner surface blackened by applying a black paint or coloring so as to prevent heat reflection on the inner surface. A part of a discharge pipe 39 guided from the sample cooling head 35 is wound around the outer surface of the sample-side heat shield case 27 to cool the sample-side heat shield case 27 from the outer surface side. Cooling coil portion 45 is formed.

On the other hand, from the four corners of the peripheral portion of the base plate 17, four columns 47A and 47B (only two columns on the near side are shown in the figure) are erected vertically upward. A top plate 49 is provided horizontally on the upper end side of 47B. The top plate 49 is rotatably supported by the support shaft 51 at the upper end of two pillars 47A on one side so as to be able to jump upward, and is supported by two pillars 47B on the other side. On the other hand, it is easily detachably attached by a thumb screw 53. On the lower surface of the top plate 49, FR
A sensor-side heat shield case 57 is suspended via a support member 55 that creates a heat insulating effect such as P. The sensor-side heat shield housing 57 includes a sensor cooling head 5 therein.
9 is fixed, and a sensor base 61 made of a good heat conductive material such as copper is attached to the lower surface of the sensor-side cooling head 59. Here, the sensor base 61 has a sensor such as a SQUID or a tunnel microscope mounted thereon.
The sensor cooling head 59 is made of a good heat conductive material such as copper in the form of a hollow tank similarly to the sample cooling head 35 described above. The helium gas introduced through the introduction pipe 63 and vaporized from the upper portion is discharged through the discharge pipe 65. An opening 57A is formed at the bottom of the sensor-side heat shield case 57 corresponding to the lower surface of the sensor base 61. Is wound around the cooling coil 67
Are formed.

Next, the cooling medium supply device 7 will be described.

In FIG. 1, an inner container 73 is provided at an interval inside an outer container 71, and
The space between the inner container 73 and the inner container 73 is suctioned by a vacuum so as to be vacuum insulated. On the lower side surface of the outer container 71, a cooling medium supply / recirculation projection 7 inserted into the cooling medium supply / recirculation opening 13 in the chamber 1 described above.
1A to 71D are formed. The inner container 73 is for storing liquid helium as a cooling medium, and has a cooling medium supply pipe 9A, which extends downward from the lower bottom (the space between the inner container 73 and the outer container 71). 9
B has been led out and these cooling medium supply pipes 9
A sample-side supply control valve 75 and a sensor-side supply control valve 77 are provided at the upper ends of A and 9B as flow rate control means. An inflow port 75 into which liquid helium in the inner container 73 is taken is provided beside these supply control valves 75 and 77.
A, 77A, and these supply control valves 75,
From 77, operation shafts 75B, 77B extend upward.

The cooling medium supply pipes 9A and 9B are led into the chamber 1 through the cooling medium supply / return projections 71B and 71D. One pipe 9A is connected to the sample side via a flexible pipe 79. The other pipe 9 </ b> B is connected to a cooling medium introduction pipe 63 on the sensor side via a flexible pipe 81. And also the cooling medium supply pipe 9A,
9B, heaters 83A and 83A as temperature control means for controlling the temperature of the cooling medium sent to the chamber 1 side.
3B is provided. In addition, below the inner container 73,
Cooling medium supply pipes 9A, 9B, heaters 83A, 83B
In addition, discharge pipes 11A and 11B are provided, and one side of each discharge pipe 11A and 11B is guided into the chamber 1 through the cooling medium supply / return projections 71A and 71C. Cooling medium discharge pipe 39,
65 are connected through flexible pipes 87 and 89, and the other end of each of the cooling medium discharge pipes 11A and 11B is led to the outside of the outer container 71, and the helium gas is discharged into the outside air at the tip thereof. Discharge ports 91A and 91B are provided.

The function and operation of the low-temperature sample position control apparatus according to the embodiment of the present invention shown in FIGS. 1 and 2 will be described below.

A sample to be measured or observed, for example, various elements such as a semiconductor element and a sample made of various materials such as a superconducting material are held on a sample table 29, and a sensor table 61 such as an SQUID or a tunnel microscope is held on the sample table 29. The sensor is mounted. Here, the positions of the sensor and the sensor base 61 are fixed from the base plate 17 via columns 47A and 47B, a top plate 49, and the like. On the other hand, the positions of the sample and the sample table 29 are roughly determined by a first position control mechanism 19 including driving devices 19A, 19B, and 19C in the X-axis direction, the Y-axis direction, and the Z-axis direction. It is determined with high accuracy by the piezoelectric element 23 as a control mechanism. That is, by operating the driving devices 19A, 19B, and 19C in the X-axis direction, the Y-axis direction, and the Z-axis direction,
1 moves in a three-dimensional direction with a relatively large moving amount and moving speed, and a piezoelectric element 23 fixed to a movable base 21, an intermediate connecting member 25, a sample base 29, a support member 31, and a sample-side heat shield case. The body 27 and the sample cooling head 35 also move in the same direction. When the piezoelectric element 23 is driven, only the intermediate connecting member 25 and the sample table 29 move minutely in each of the three-dimensional directions. Here, the sample stage 29 is in a non-contact state with the sample-side heat shield housing 27, and the heat conducting member 41 between the sample stage 29 and the sample cooling head 35 has flexibility. 23 allows the sample table 29 to be moved with a minute precision.

On the other hand, liquid helium is stored as a cooling medium in the inner container 73 of the cooling medium supply device 7, and this liquid helium is supplied from the sample side supply control valve 75 and the sensor side supply control valve 77 to the cooling medium supply pipe 9A. , 9B, flexible pipes 79, 81, cooling medium introduction pipes 37, 6
The sample 3 is introduced into the sample cooling head 35 and the sensor cooling head 59 through 3. Here, the flow rate of the liquid helium guided to each of the cooling heads 35 and 59 is controlled by operating the operation shafts 75B and 77B of the supply control valves 75 and 77, respectively. The temperature of the liquid helium or vaporized helium gas guided to each of the cooling heads 35 and 59 is controlled by the heater 83.
A, 83B. For example, SQ
When the UID is used, the flow rate and the temperature of the liquid helium are controlled so that the temperature of the sensor cooling head 59 is about 4K, and the temperature of the sample cooling head 35 is set to, for example, 4K to 100K according to the type of the sample. Control within the range. The helium gas vaporized by the temperature rise in each of the cooling heads 35 and 59 is discharged to the discharge pipes 39 and 65.
Flexible pipes 87 and 89, discharge pipe 11A,
It is guided to discharge ports 91A and 91B via 11B and discharged to the atmosphere. Here, the discharge pipes 39, 6
5 is wound around the outer surfaces of the heat shield casings 27 and 57 as the cooling coil parts 45 and 67, so that the relatively low-temperature helium gas discharged from the cooling heads 35 and 59 is supplied to the respective heat shields. This contributes to cooling the housings 27 and 57.

In the sample-side heat shield housing 27,
Heat is transferred from the cooling head 35 to the sample stage 29 via the flexible heat conductive member 41, and the sample stage 29 and the sample held therein are cooled to a temperature within a range of, for example, 4K to 100K. Here, when liquid helium is introduced into the sample cooling head 35 from the cooling medium supply device 7 through each pipe, mechanical vibration is generated along with the movement of the liquid helium, and the cooling head 35 and the heat shield casing are generated. 27 also vibrate, but the heat conducting member 41 connecting the cooling head 35 and the sample table 29 has flexibility and is always bent, and the sample table 29 is a heat shield case. Since it is not in contact with the body 27, the transmission of vibration on the side of the cooling head 35 and the heat shield housing 27 to the sample table 29 is minimized. Therefore, the position of the sample can be controlled with high accuracy without being affected by the vibration of the cooling head 35 and the heat shield housing 27. Further, since the vibration of the sample table 29 is unlikely to occur, the application of mechanical stress due to the vibration to the piezoelectric element 23 is minimized, so that the piezoelectric element 23 having a low mechanical strength is Can be effectively prevented from being destroyed.

To supplement the cooling of the sample, the intermediate connecting member 25 between the sample stage 29 and the piezoelectric element 23 is made of FRP or the like having a heat insulating effect. Is prevented as much as possible. In addition, the sample side heat shield case 2
7 is cooled by the cooling coil part 45 as described above, and the heat shield housing 27 and the movable base 21 are cooled.
Is formed of a material having a heat insulating effect such as FRP, thereby preventing heat from entering the heat shield housing 27 from the movable table 21 side. Can be maintained at a low temperature. Further, since the cooling head 35 is supported by the cooling head base 33 made of a material having a heat insulating effect such as FRP in the sample-side heat shield housing 27,
Heat penetration into the cooling head 35 is also small. Therefore, together with these effects, the sample on the sample stage 29 can be efficiently cooled to a low temperature, and the consumption of liquid helium can be reduced.

The sensor-side heat shield case 57 is also cooled to a low temperature by the cooling coil portion 67 on its outer surface, and the support member 55 between the heat shield case 57 and the top plate 49 also has a heat insulating effect such as FRP. Is made of a material having the following, heat intrusion into the sensor-side heat shield case 57 can be prevented as much as possible, and the sensor-side heat shield case 57 can be kept at a low temperature. The sensor attached to it can be efficiently kept at a cryogenic temperature to reduce the liquid helium consumption. Since the sensor base 61 is rigidly fixed from the side of the top plate 49 as described above, the vibration of each pipe due to the introduction of the liquid helium into the cooling head 59 causes the sensor base 61 to vibrate.
Is less likely to vibrate.

As described above, while the sample and the sensor are efficiently cooled and kept at a low temperature, the sample and the sensor are not affected by the vibration from the sample cooling head 35 due to the introduction and discharge of the liquid helium or the like. High-precision position control on the order of microns can be performed.

When the SQUID is used as a sensor, it is necessary to suppress the influence of external magnetism. In the apparatus of the embodiment, the magnetic shields 15A and 15A are provided inside the chamber 1.
B, the intrusion of magnetic flux from the outside can be suppressed, and the lower part in the chamber where the first position control mechanism 19 including the driving devices 19A to 19C such as pulse motors is located inside the chamber 1 Magnetic shield between the sensor and the upper part of the chamber where the sensor and sample are located
Therefore, it is possible to effectively prevent the sensors and the sample from being affected by magnetic flux by the driving devices 19A to 19C such as pulse motors. Further, the heaters 83A and 83B for controlling the temperature of the cooling medium and the control valve 7 are provided.
5 and 77 are often sources of electromagnetic noise and magnetic noise. In the embodiment, these heaters 83A and 83B and control valves 75 and 77 are provided with a cooling medium outside the chamber 1 (and thus outside the magnetic shield 15A). Since the sample and the sensor are provided on the side of the supply device 7, the heaters 83A and 83A
B and the control valves 75 and 77 are not affected by electromagnetic noise or magnetic noise. Each heat shield case 27,
57 can be provided with not only a heat shield but also a function of a magnetic shield by forming them from a high magnetic permeability magnetic material, thereby further reducing the influence of external magnetism. can do.

Further, in the apparatus according to the embodiment, when exchanging the sample (attachment / removal) or exchanging the sensor,
When the upper chamber 1A of the chamber 1 is removed from the lower chamber 1B, the chamber 1 is opened, the thumb screw 53 is removed, and the top plate 49 is flipped up around the support shaft 51, so that the sample portion and the sensor portion are exposed. Therefore, these exchanges can be easily performed. Here, when the chamber 1 is opened, the vacuum in the chamber 1 is broken, but the cooling medium supply device 7 is isolated from the chamber 1 and the inner container 73 and the outer container of the cooling medium supply device 7 are separated. The vacuum state between the vacuum chamber 71 and the vacuum chamber 71 is not broken even when the chamber 1 is opened. Therefore, even when the chamber 1 is opened, the liquid helium as the cooling medium in the inner container 73 of the cooling medium supply device 7 can be stored as it is without evaporating.

In the case of the apparatus of the embodiment, the position of the sample can be visually checked through the optical window 3 of the chamber 1 and the opening 27C of the sample-side heat shield case 27. In such a configuration, radiant heat easily enters the sample from the outside through the optical window 3, but the radiation shield pipe 43 extends from the opening 27 </ b> C of the sample-side heat shield housing 27 toward the optical window 3. Therefore, there is little possibility that radiant heat from the optical window 3 reaches the sample.

[0040]

According to the device of the first aspect, basically,
A sample cooling head for cooling the sample and a sample stage for holding the sample are separated from each other in the sample-side heat shield case, and the space between the sample cooling head and the sample stage is allowed. It is connected by a heat conducting member having flexibility, and is configured to cool the sample stage and the sample by heat conduction of the flexible heat conducting member, so that a cooling medium flows into the sample cooling head, The mechanical vibration of the cooling head due to the discharge is prevented from being transmitted to the sample stage and the sample, so that the influence of the vibration may reduce the position accuracy of the sample or make accurate measurement difficult. In addition, since the vibration accompanying the introduction and discharge of the cooling medium into and from the sample cooling head is not transmitted to the sample table side, the supporting portion of the sample table is prevented to prevent the vibration. rigidity Extreme is not necessary to increase, because therefore it is possible to reduce the heat penetration into the sample table and the sample through the support portion from the outside, to enhance the cooling efficiency,
The sample can be cooled to a sufficiently low temperature and the consumption of the cooling medium can be reduced.

In the apparatus according to the second aspect of the present invention, the position control means comprises a first position control mechanism for performing rough position control and a second position control mechanism for performing fine position control. Therefore, the time for the position setting and the position control can be shortened to improve the work efficiency, and at the same time, the minute position control can be performed with extremely high accuracy.

In the apparatus according to the third aspect of the present invention, the piezoelectric element which is relatively weak against mechanical stress is used as the second position control mechanism. It is difficult for the vibration accompanying the vibration to be transmitted to the sample stage, and therefore, the mechanical stress is prevented from being applied to the piezoelectric element by the vibration of the sample stage. Therefore, the piezoelectric element is prevented from being destroyed by the mechanical stress. be able to.

Further, in the apparatus according to the fourth aspect of the present invention, since the sample stage is in non-contact with the sample side heat shield case, the vibration accompanying the introduction and discharge of the cooling medium to and from the cooling head. Accordingly, even when the sample-side heat shield case vibrates, it is possible to prevent the vibration of the heat shield case from being transmitted to the sample stage.

On the other hand, in the case of the apparatus according to the fifth aspect of the present invention, since the sample table and the sensor table are magnetically shielded from the outside, measurement such as measurement by SQUID which dislikes the influence of magnetic noise and electromagnetic noise is performed. Even in this case, highly accurate measurement can be performed with a small error without being affected by external magnetic noise or electromagnetic noise.

According to the sixth aspect of the present invention, there is provided the first aspect.
As in the case of the invention of claim 4 and the invention of claim 4, the vibration accompanying the introduction and discharge of the cooling medium to the cooling head is prevented from being transmitted to the sample stage and the sample, and therefore, the minute precision with high precision can be prevented. The position control becomes possible, the sample stage can be cooled efficiently, and the rough position control is performed by the first position control mechanism as in the case of the second aspect of the present invention.
Further, since minute position control can be performed by the second position control mechanism, time for position setting and position control can be shortened, and work efficiency can be improved.

According to the seventh aspect of the present invention, the piezoelectric element which is susceptible to mechanical stress is used for minute position control similarly to the third aspect of the present invention. There is little possibility that mechanical stress is applied, and therefore, it is possible to prevent the piezoelectric element from being broken.

Further, according to the invention of claim 8, according to claim 5,
Since the magnetic shield is provided in the same manner as in the first aspect of the invention, highly accurate measurement can be performed with a small error without being affected by external magnetic noise and electromagnetic noise.

In the apparatus according to the ninth aspect of the present invention, the vacuum space in the chamber and the vacuum space for heat insulation of the cooling medium supply device are isolated from each other. Even if the vacuum in the chamber is broken to perform the operation, the vacuum space for the heat insulation of the cooling medium supply device is kept as it is, and therefore, when performing the above-described replacement or the like in the chamber, the inside of the cooling medium supply device is not changed. Since the cooling medium can be held as it is without causing the cooling medium to evaporate due to the temperature rise, it is possible to effectively prevent the cooling medium from being unnecessarily consumed by the above-described replacement work or the like.

Further, in the apparatus according to the tenth aspect of the present invention, the means for controlling the flow rate and temperature of the cooling medium is provided on the side of the cooling medium supply device, while the sensors and samples on the chamber side are magnetically shielded. In addition, there is no possibility that magnetic noise or electromagnetic noise generated by the flow rate control means or the temperature control means will adversely affect the measurement of the device.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing an entire configuration of an embodiment of a low-temperature sample position control device according to the present invention.

FIG. 2 is a schematic longitudinal sectional view showing an enlarged main part of the apparatus of the embodiment shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 chamber 7 cooling medium supply device 15A, 15B inner surface magnetic shield 15C upper and lower section magnetic shield 19 first position control mechanism 21 movable base 23 piezoelectric element (second position control mechanism) 25 intermediate connection member 27 sample side heat shield Case 29 Sample stand 31 Support member 33 Cooling head base 35 Sample cooling head 37 Cooling medium introduction pipe 39 Cooling medium discharge pipe 41 Flexible heat conductive member 57 Sensor side heat shield case 59 Sensor cooling head 61 Sensor stand 63 Cooling medium introduction pipe 65 Cooling medium discharge pipe 71 Outer vessel 73 Inner vessel 75 Sample side supply control valve (flow rate control means) 77 Sensor side supply control valve (flow rate control means) 83A, 83B Heater (temperature control means)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G01N 1/28 K (72) Inventor Yasuharu Kamioka 2-4-11 Utsumotocho, Nishi-ku, Osaka-shi, Osaka Taiyo Toyo Oki Stock In-company (72) Inventor Odawara Shikei 1-8 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Instruments Inc. (72) Inventor Kazuo Kaine 1-8 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Instruments Inc. (72) Inventor Satoshi Nakayama 1-8 Nakase, Mihama-ku, Chiba-shi F-term in Seiko Instruments Inc. (reference) 2G017 AB05 AB06 AC01 AC03 AC04 AC05 AC06 AD32

Claims (10)

[Claims] 1. A sample stage for holding a sample, a sensor stage for holding a sensor facing the sample on the sample stage, a sample cooling head for cooling the sample to a low temperature, and for cooling the sensor. A sensor-side cooling head, a sample-side heat shield housing for thermally shielding the sample stage and the sample cooling head, and a sensor-side heat shield housing for thermally shielding the sensor stage and the sensor cooling head. Position control means for controlling the position of the sample stage in a three-dimensional direction, wherein the sample cooling head and the sensor cooling head are configured such that a cooling medium flows in and out from the outside, respectively, and The sample cooling head and the sample stage are arranged separately from each other in a sample-side heat shield case, and a heat conducting member having flexibility between the sample cooling head and the sample stage. Characterized in that the sample stage and the sample are cooled to a low temperature via the flexible heat conducting member. 2. A first position control mechanism in which the position control means performs position control in a three-dimensional direction with a relatively large movement amount, and a movable table which is moved by being position-controlled by the first position control mechanism. And a second position control mechanism interposed between the movable table and the sample table and performing position control in a three-dimensional direction with a relatively small amount of movement. The low-temperature sample position control device according to claim 1, wherein the low-temperature sample position control device is attached to the movable base via a support member having flexibility. 3. The low-temperature low-temperature apparatus according to claim 2, wherein the second position control mechanism is made of a piezoelectric element, and an intermediate connecting member having heat insulating property is interposed between the piezoelectric element and the sample table. Sample position control device. 4. The sample-side heat shield case is fixed to the support member, and the sample stage is arranged in the sample-side heat shield case so as not to be in contact with the sample-side heat shield case. The low-temperature sample position control device according to claim 3, wherein 5. The low-temperature sample position control device according to claim 1, further comprising a magnetic shield surrounding at least the whole of the sensor stage, the sensor cooling head, the sample stage, and the sample cooling head. 6. In a chamber capable of maintaining a vacuum inside;
A first position control mechanism that performs position control with a relatively large movement amount in a three-dimensional direction, a movable table whose position is controlled by the first position control mechanism, and a support member having heat insulation properties on the movable table. A sample-side heat shield case attached via the heat shield case and a cooling head base having thermal insulation inside the sample-side heat shield case, and a cooling medium is introduced and discharged from the outside. A sample cooling head, a sample table provided in the sample-side heat shield housing in a non-contact state with the housing and separated from the sample cooling head, and attached to the movable table. A second position control mechanism for controlling the position of the sample stage with a relatively small amount of movement in the three-dimensional direction, and a flexible heat transfer link between the sample cooling head and the sample stage. Components,
A sensor base facing the sample base, a sensor cooling head for cooling the sensor base by introducing and discharging a cooling medium from the outside, and a sensor side heat source surrounding the sensor base and the sensor cooling head. A sensor-side heat shield housing provided separately from the shield housing, and a sensor-side support member for supporting the sensor base, the sensor cooling head, and the sensor-side heat shield housing to fix their positions. A low-temperature sample position control device, which is provided. 7. The low-temperature low-temperature apparatus according to claim 6, wherein the second position control mechanism comprises a piezoelectric element, and an intermediate connecting member having thermal insulation is interposed between the piezoelectric element and the sample stage. Sample position control device. 8. The low-temperature sample position control according to claim 6, wherein a magnetic shield is provided at least in a portion surrounding the sensor stage, the sensor cooling head, the sample stage, and the sample cooling head in the chamber. apparatus. 9. A cooling medium supply device for supplying a cooling medium to the sample cooling head and the sensor cooling head is provided outside the chamber, and the cooling medium supply device includes an outer container and a cooling medium supply device. The inner container is configured to have at least a double structure, configured to store a cooling medium in the inner container, and configured to be able to maintain a vacuum between the inner container and the outer container, 9. The low-temperature sample position control device according to claim 8, wherein the vacuum part and a space part held in the chamber in a vacuum are hermetically isolated. 10. A flow rate control means and a temperature control means for controlling a flow rate and a temperature of a cooling medium supplied from an inner container of the cooling medium supply device to a sample cooling head and a sensor cooling head in the chamber. The low-temperature sample position control device according to claim 9, wherein the low-temperature sample position control device is provided in the cooling medium supply device.