JPS5855616B2 - Sample equipment such as scanning electron microscopes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for analyzing a frozen sample in a charged particle beam device.
The present invention relates to an observation device, and particularly to a sample device suitable for use in a scanning electron microscope.

Observation of frozen samples is considered to be very important, especially in the field of biological sample observation using scanning electron microscopy, since it is thought that the observation can be made in the same state as when alive.

However, the frozen sample observation equipment requires a cooling device to keep the sample in a frozen state, a means to prevent frost from adhering to the sample while handling the frozen sample, and a means to cut the surface even if frost forms. It is necessary to expose a fresh surface of the sample.

For this reason, in the conventional technology, a preliminary chamber is provided which is connected to the sample chamber of the scanning electron microscope and can be vacuum isolated from the sample chamber by an air lock device. A method has been proposed in which a cutting means such as a knife is provided to process the sample.

However, the cooling device is fixed in the preliminary chamber and is separate from the cooling device in the sample chamber.

Therefore, in the conventional technology, in order to maintain the frozen state of the sample,
It requires a cooling device in each of the sample chamber and the preliminary chamber, making it extremely complicated and difficult to operate as an apparatus for cryoscopic observation, and has drawbacks such as high cost and high refrigerant consumption. There is.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a sample device for observing a frozen sample that is easy to operate and has a simple configuration.

FIG. 1 is an embodiment of the present invention, and is a schematic longitudinal cross-sectional view showing the basic configuration.

In the figure, a sample processing chamber 2 provided in communication with a sample chamber 1 of a scanning electron microscope or the like is appropriately vacuum-blocked by an air lock valve 3.

A cooling device 4 is attached to this sample processing chamber 2. The cooling device basically consists of a cooling tank 5 covered with a heat insulating material such as styrofoam, and one end of which is connected to a cooling medium such as liquid nitrogen.
A cooling body 7 immersed therein, a cooling tank support 8 surrounding the cooling body and sliding between the sample chamber 1 and the sample processing chamber 2 and having a vine shape, and located outside the cooling tank support, The cooling device is composed of a cooling device moving table 9 that can be moved vertically and horizontally at the same time when the entire cooling device is installed in a sample processing chamber, and a sample temperature control device 10 for controlling the sample temperature.

The sample temperature control device 10 controls the sample holder 1 of the cooling body 7.
A heater 12 provided at one end of the side on which the sample holder 1 is placed, its lead wire 13, and a thermocouple 14 provided near the sample holder 11.
, an introduction terminal 15 such as a hermetic seal for connecting these lead wires to the outside of the vacuum, a heater power source 16 and a thermocouple meter 11 connected to this outside of the vacuum.

The sample 18 is usually immersed in liquid nitrogen or the like in the atmosphere and frozen, and then mounted on the cooling body 1 (C) together with the sample holder 11 via any means to prevent frost from adhering.

The attachment may be carried out within the sample processing chamber, or a separate sample exchange device (
(not shown).

Sample 18 and sample holder 11 mounted on cooling body 7
If you want to perform treatments such as cutting the sample surface or applying conductive treatment, move the entire cooling device between the cooling tank support 8 and the vacuum sealing O-ring 19 while sliding it on the sample processing chamber side.
・Pull out.

Also, when observing a frozen sample, push it out to the sample chamber side.

At this time, fine movement of the sample relative to the irradiation electron beam 20 is performed by operating the fine movement knob 21 of the cooling device moving table 9.

For this reason, a vacuum-sealing metal O-ring 22 that is easy to slide is provided between the cooling device moving table 9 and the side surface of the sample processing chamber facing thereto.

Further, fine movements in the front and rear directions (in the left-right direction in the drawing) are performed by a moving ring 23.

On the other hand, when the cooling tank 5 is rotated, the cooling tank support and the cooling body 1 are also rotated at the same time.
Slope with respect to 0.

Full angle tilting is also possible, and therefore a cap 24 is attached to the cooling tank 5 to prevent the refrigerant 6 from spilling out even when observed at a high tilt angle.

Although the sample temperature control device 10 is attached to the cooling device 4, it is not necessary to stick to this, and it may be provided separately through a part of the sample chamber and brought into contact with the cooling device as necessary. good.

Further, although the cooling body 1 is shown as an integral body in this embodiment, in order to reduce direct vibration from the refrigerant, the cooling body 1 may be relayed with a braided wire such as a thin copper wire in the middle of the cooling body. .

FIG. 2 is a schematic cross-sectional view of another embodiment.

In this example, a sample exchange chamber 25 is provided in the sample processing chamber 2.

An air lock valve 26, a gas leak valve 21, and a sample exchange rod 28 are attached to the sample exchange chamber 25, and after introducing dry gas into this sample exchange chamber during sample exchange, the exchange chamber is operated by an oil rotary pump (not shown). etc., and is exhausted.

Then, the cooling device 4 is pulled out to the sample processing chamber 2 as shown in the figure, and the sample is exchanged without exposing the sample processing chamber to the atmosphere.

Therefore, it is possible to prevent frost from adhering not only to the sample but also to the cooling device, which has the advantage of allowing smooth evacuation after replacement.

FIG. 3 is a schematic configuration diagram showing still another embodiment of the present invention.

In this example, the sample processing chamber 2 is equipped with various sample processing functions to enable accurate observation of the surface morphology of frozen samples.

One is a cooling knife 29 for cutting away the frosted surface of a frozen sample to reveal a fresh sample surface.

The cooling knife is vacuum-sealed by, for example, an O-ring 30, moves up and down, contacts the cooling body 7, and is cooled in advance.

After that, the sample is set at the cutting height and rotated so that the sample is cut along the desired plane.

The sample is cut while looking into the sample chamber through the observation window 31.

Furthermore, the cut end of the sample after cutting can be observed in detail using an optical microscope or a magnifying glass (not shown).

Similar to the cooling knife, a sample manipulator 32 for picking up or gouging the sample is also provided in a part of the sample processing chamber, and is used for sample processing after being brought into contact with the cooling body 1 and cooled.

One of the other functions is an ion sputtering device 36 consisting of an ion sputtering electrode 34 and its power source 35 attached to the sample processing chamber via an insulator 33.

This ion sputtering power source 35 includes both AC and DC power, so that both ion etching by ion sputtering and conductive processing can be used as necessary.

One of the other functions is a heater source 38 and its power source 39 consisting of a filament, such as a tungsten wire, provided through an insulator 37.

There are two types of heater sources: one for sublimating frost on the surface of a frozen sample by radiant heat, and the other for vacuum-depositing gold, platinum, etc. on the surface of the sample, and a plurality of heater sources may be provided as necessary.

These functions can be installed in any part of the sample processing chamber because the cooling device 4 itself, which holds the sample 18 and its holder 11, can be tilted forward, backward, left, right, up, down, and at all angles. This is one of the great advantages of the present invention.

FIG. 4 is a schematic diagram showing still another embodiment of the present invention.

In this example, the sample processing chamber 2' is provided in the sample chamber 1 facing the cooling device 4, and a sample exchange chamber 25 is further added to the sample processing chamber, and an air lock valve 26, a gas leak valve 27' and a sample exchange chamber 25 are provided. A replacement rod 28 etc. are attached.

In this example, vacuum sealing between the sample chamber 1 and the sample processing chamber 2 can be achieved by sliding the surface of the O-ring 40 provided at the interface between the sample chamber 1 and the sample processing chamber 2 on the cooling tank support 8. This has the advantage of simplifying the airlock function.

Further, as shown in the figure, the sample tensioning device 41 has the convenience of being able to utilize space very effectively.

Furthermore, it can also be used as a similar device, such as a frozen sample destruction device (not shown).

According to the present invention, the sample device has the advantage of being simpler in structure and easier to operate than ever before.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical cross-sectional view showing one embodiment of the present invention, Fig. 2 is a schematic plan cross-sectional view showing another embodiment, and Fig. 3 is a longitudinal cross-sectional view showing another embodiment of the sample processing chamber portion. FIG. 4 is a schematic plan view showing another embodiment. 1... Sample chamber, 2, 2... Sample processing chamber, 3.26
゜26'...Air lock valve, 4...Cooling device, 5
...Cooling tank, 6...Refrigerant, 1...Cooling body, 8...
・Cooling device moving table, 10...Sample temperature control device, 11
...sample support, 12...heater, 14...
・Thermocouple, 18...sample, 21...fine movement knob, 2
5, 25... Sample exchange room, 29... Cooling knife, 31... Observation window, 32... Sample manipulator,
36... Ion sputtering device, 38... Heater source, 39... Heater power source, 41... Sample tensioning device.

Claims (1)

[Scope of Claims] 1. An apparatus for introducing a frozen sample into a holding chamber for observation, comprising a cooling means for cooling the sample, a sample temperature control device for controlling the sample temperature, and the cooling means. The sample holder is provided with a sample holder for holding a sample provided in the sample chamber, and a sample processing chamber that communicates with the sample chamber through an air lock means. . A sample apparatus such as a scanning electron microscope, characterized in that the position is variable as the cooling means moves. 2. A device for introducing a frozen sample into a sample chamber for observation, including a cooling means for cooling the sample, a sample temperature control device for controlling the sample temperature, and a sample holding device installed in the cooling means. σ) A sample holder and a sample processing chamber communicated with the sample chamber via an air lock means, and the sample holder moves between the sample chamber and the sample processing chamber by the movement of the cooling means. A sample apparatus such as a scanning electron microscope, characterized in that the sample exchange chamber is attached to the processing chamber via an air lock means, and the sample exchange chamber is provided through an air lock means.