DE2325994B2 - Object holding device for electron microscopes - Google Patents

Description

The invention relates to an object holding device for electron microscopes with a vacuum settable object table and an adjustment device for correcting the position of the object in which one Carrying device for the object table airtight into the inside of an object chamber from the outside atmosphere separating chamber wall is fitted through wall opening.

In known object holding devices of this type (DT-OS 15 39 718), the position of the object in the operating vacuum determined from the outside with the help of a slide. The slide comes with a special one Device for determining its axial position provided, this device is based on a rotating part on the evacuated chamber from which it is sealed. The structure is complicated and poses not sure that in the event of external shocks the sample will not vibrate with respect to the chamber-fixed Share executes.

The invention is based on the object of an object holding device to create the type mentioned, in which the object in constructive as possible is held in a simple manner secured against vibrations in the operating position.

This is achieved according to the invention in that the support device is designed in such a way that the object table in the operating state by the atmospheric pressure at a magnetic pole of the objective electron lens or a similar stationary part of the electron microscope is supported.

This ensures that the operational. State the external atmospheric pressure fixes the carrying equipment in its deployed position extremely easily, as soon as the interior of the object chamber for loading <; operating state is evacuated. In addition, at Changing an object of the object table can be made accessible without difficulty by turning the The interior of the specimen chamber is ventilated and then the carrying device with the specimen table out of the chamber

Furthermore, by pressing the object table or a part thereof under atmospheric pressure against a magnetic pole of the objective electron lens device or a correspondingly fixed part of the electron microscope prevents vibrations from occurring during operation The point of impact of the electron beam on the object remains there:; r unchanged even with external vibrations.

In a particularly preferred embodiment, the Carrying device a round rod-shaped, directly with the bottom center of a cylindrical object table connected inner shaft and a round rod-shaped outer shaft. the one in the wall opening is guided tightly and rotatably and that of the inner shaft coaxially and eccentrically in tight rotary bearing is penetrated. Such an arrangement with Innenurd Outer shaft is known per se from German patent application A 7 09 421 g 37/10. Since the inner shaft, which is directly connected to the lens table, is dense and in an eccentric arrangement is rotatably mounted coaxially in the outer shaft, which in turn is sealed and rotatable in the wall opening of the Object chamber is stored, the position of the object table or the position of the incident on an object Adjust or correct the electron beam in a simple manner by turning the two shafts. One Such a device for correcting the position of the object is particularly simple.

In a further preferred embodiment is on the outside At the end of the inner shaft an adjustment member is arranged with an adjustment zone which is approximately the size of the receiving opening of the cylindrical stage for the object, this adjustment zone is the position of the Associated display part reproducing the electron beam on the object.

In general, extremely complicated arrangements are required to display the position of an electron beam hitting an object, and / was while using the electron microscope. In the case of the object holding device according to the In contrast, the preferred embodiment described above is in the form of the setting part with the setting zone, for example Size of the recess provided in the object table for the object and coaxial alignment with this one especially simple display device created, even with fine adjustment of the position of the object reflects the change instantly and without gaps. In spite of the achievable accuracy the structure of such a device is extremely simple and stable.

The invention is explained in more detail below using an exemplary embodiment shown schematically in the drawing. It shows

F i g. 1 is a side sectional view of an embodiment of the object holding device according to the invention a scanning electron microscope,

F i g. FIG. 2 shows a view of the exemplary embodiment according to FIG

3 4

F i g. 1 in the direction of the arrows H-II. see electricity is converted to an enlarged image

As can be seen from the drawing, an outer part of the desired part of the object is represented by a (not

shaft 3 with a circular cross-section by means of an amplifier shown) towards a Braun tube

Project the m-ring 4 in a wall opening 2 in a sealing and rotating manner.

out stored bar, which is in a wall la a 5 In the case of the above structure having

Object chamber 1 is located. Object holding device for electron microscopes

An inner shaft 6 with a likewise circular transverse adjustment is a fine adjustment or correction of the position

cut, one end of which cannot be smacked with the center 11a, in which the electron beam 12 hits the object 11

strand of the bottom of a cylindrical object table 5 in hits, by rotating the outer shaft 3 and the

Connection is, is effected in an axially parallel, eccentric 10 inner shaft 6, which latter is relative to the

trically arranged bore is arranged eccentrically via an O-ring seal outer shaft, namely

device 7 tightly mounted rotatably in the outer shaft. by holding the upper end of the outer shaft 3

On the bottom circumference of the object table 5 is a flange and the adjustment part 9. The changed by this process

5a formed, which with a step part 2a of the wall dene the irradiation position of the electron beam on the

Opening 2 of the object chamber wall is in engagement, the 15 object is through the display part 13a of the display element

fixed at a magnetic pole 8 of an electron lens mems 13 displayed on the adjustment zone 9a,

is. If the interior of the object chamber 1 is under vacuum, despite such an adjustment of the position of the object

If the flange 5a is put under the atmosphere, the flange 5a of the object table 5 always remains

spherical external pressure always against the step part against the fixed at the magnetic pole 8 of the electron lens

2a pressed. 20 laid step part 2a pressed. Thereby the irradiation

An adjustment part 9 with approximately the size of the position of the electron beam on the object free of

Receiving opening of the stage 5 for the object held on external vibration influences, and the image

pointing adjustment zone 9a is not disturbed by a screw 10 of the Braun tube,

fixed at the outer end of the inner shaft 6. To replace the object 11, the evacuated

In the middle of the circular bottom of the specimen table is the ventilated interior of specimen chamber 1, d. H. again

while being coaxial with the center of the adjustment zone 9a. exposed to atmospheric pressure, the display element

Also provided is a display element 13 with meni 13 is pivoted upwards and the outer

a display part 13a which shows the respective position 11a of the shaft 3 together with the object table 5 and

Electron beam 12 drawn out of the wall opening on an on the object table with the inner shaft 6.

holding object 11 indicates and is close to said 30 gene. Then the object held on the object table 5

Check zone 9a is located. 11 changed.

The display element 13 is via a pivot axis. The object table 5 can easily be returned to

14 mounted on a support cylinder 15, which in turn can be arranged in the object chamber 1 by

is attached to the object chamber wall la. In this it together with the inner shaft 6 and the outer

Support cylinder 15, a spring 16 is arranged, the shaft 3 in the 35 located in the object chamber wall

The bearing of the display element 13 pushes in via a stamp wall opening 2. When generating a variable

15a push-button. Due to the external shape kuums inside the object chamber 1 are both

of the bearing, it is possible to separate the display element inwards in two of the inner and outer shafts.

To pivot stable positions, namely once in gene and thus seal the wall opening 2 hermetically

the working position in which the display part 13a of the input 40 from. The stage 5 is in its predetermined

Positioning zone 9a is assigned, and on the other hand held in one position, with the flange 5a of the object table

90 degrees pivoted position in which the removal 5 is pressed supported on the step part 2a. the

tion of the outer shaft 3 from the wall opening indicates the impact position of the electron beam

becomes possible. the display part 13a and correcting the position of the

In the drawing, reference numeral 17 denotes an object by rotating the inner shaft 6 and the collector network, 18 a scintillator, 19 a photo outer shaft 3 of the lens table are also electron-guiding part and 20 a photo-electric as described above.
nen multiplier specified. As has already been explained in detail, the invented object 11 has the advantages of an object holding device for electrons that is scanned with an electron beam 12, the microscope generated thereby from the surface of the ob- 5 °. that the construction in project outgoing secondary electrons is simplified to a great extent, the operation is simply captured by the collecting net 17 and directed to the scintillator and the maintenance of the incidence position of the 18, where they are converted into light, the electron beam on the object is improved,
then in the photoelectron multiplier 20 in electrical

1 sheet of drawings

Claims (3)

Patent claims: 1. Object holding device for electron microscopes with an object table that can be placed under vacuum and an adjustment device for correcting the position of the object, in the case of a support device for the object table airtight into the inside of an object chamber from the outside atmosphere separating chamber wall is fitted through wall opening, characterized in that that the support device (3, 6) is designed so that the object table (5) is in the operating state by the atmospheric pressure at a magnetic pole (8) of the objective electron lens or a similar stationary part of the electron microscope is supported. 2. Device according to claim 1, characterized dadurcii, that the support device (3, 6) has a round rod-shaped, directly with the bottom center the cylindrical object table (5) connected inner shaft (6) and a round rod-shaped Has outer shaft (3) which is guided tightly and rotatably in the wall opening (2) and which is penetrated by the inner shaft (6) axially parallel and eccentrically in a tight rotary bearing. 3. Apparatus according to claim 2, characterized in that at the outer end of the inner shaft (6) an adjusting member (9) with an adjusting zone (9a) approximately the size of a receiving opening of the cylindrical Object table (5) is provided for the object (11), which setting zone (9a) is the Display part reproducing the position of the electron beam (12) of the electron microscope in relation to the object (31) (13,13a) is assigned.