JPH08111200A - Scanning electron microscope - Google Patents

Abstract

(57) [Summary] [Structure] A hole 4 for pre-evacuation is provided on the surface separating the sample chamber 1 and the sample exchange chamber 2, and the sample chamber 1 is pre-evacuated in the sample exchange chamber 2.
In addition to the preliminary evacuation hole 4, the sample exchange hole 3 and the air leak hole 5 can be opened and closed by a series of operations of one handle. [Effect] The rotary pump for pre-evacuation, the exhaust pipe, the vacuum gauge, the solenoid valve, etc. required for the pre-evacuation sequence, which were required for the conventional sample exchange, are no longer required, and the cost can be significantly reduced. In addition, the sample exchange can be performed in a shorter time with a simple operation and configuration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning electron microscope, and more particularly to a scanning electron microscope in which a hole for pre-evacuation is provided on a surface separating a sample chamber and a sample exchange chamber, and vacuum of the sample chamber is used for pre-evacuation. Regarding the microscope.

[0002]

2. Description of the Related Art A conventional scanning electron microscope generally uses a dedicated rotary pump for preliminary evacuation of a sample exchange chamber, or a scanning electron microscope capable of low-vacuum observation also serves as a rotary pump for exhausting the sample chamber. I was there. Such a scanning electron microscope is the one shown in FIG. 3, which is functionally sufficient, but is high in cost and complicated in structure and operation.

[0003]

FIG. 3 schematically shows the structure of a sample chamber portion of a conventional general scanning electron microscope capable of low-vacuum observation. The sample exchange chamber 2 allows the sample exchange without changing the pressure of the sample chamber 1 and the electron gun section 18 to atmospheric pressure. Therefore, the sample exchange time can be shortened and the life of the electron gun filament 18 can be extended. To do.

The procedure for sample exchange when the sample chamber is in a high vacuum is as follows. First, in order to take out the sample 16 after observation, the exchange valve 26 in the sample exchange chamber is closed, the preliminary exhaust valve 25 is opened, and the sample is exchanged by the rotary pump 23. Pre-evacuate the room. At this time, the low vacuum valve 30 and the needle valve 29 remain closed and are not used when the sample chamber has a high vacuum. After confirming the vacuum with the vacuum gauge 19, the preliminary exhaust valve is closed, the exchange valve is opened, the exchange rod 12 is inserted into the sample chamber and connected to the sample stand, the sample is pulled back into the sample exchange chamber, and then the exchange valve is closed. The air leak valve 24 is opened to make the exchange chamber atmospheric, and the exchange port 14 is removed to exchange the sample. After the sample exchange, the sample exchange chamber is pre-evacuated again, and after confirming the vacuum, the exchange valve is opened and the sample is inserted to the observation position in the sample chamber. As described above, there is a problem that the sample exchange requires complicated procedures such as opening and closing of each valve and confirmation of the degree of vacuum, and the configuration becomes complicated. Particularly when the sample chamber has a low vacuum, in order to prevent the vacuum level of the exchange chamber from lowering than the vacuum level of the sample chamber, the vacuum level of the sample chamber by the vacuum gauge 28 and the vacuum level of the sample exchange chamber by the vacuum gauge 19 are preliminarily exhausted. It is necessary to adjust the degree of vacuum in the sample exchange chamber with the needle valve 22 so that the degree is the same. To automatically perform this, a motor 20 for moving the needle valve 22, a comparison circuit 21 for comparing the degree of vacuum, and the like are also required. Therefore, both operation and configuration become complicated and costly. Furthermore, due to the conductance of the exhaust pipe and valve from the rotary pump to the exchange chamber, it takes time to pre-evacuate the sample exchange chamber. It will be long.

An object of the present invention is to reduce the cost by simplifying the operation and the structure of the sample exchange chamber using the sample exchange chamber in the low vacuum state of the sample chamber, and also for exchanging a large sample in a short time. It is to provide a scanning electron microscope.

[0006]

In order to achieve the above object, in the present invention, a hole for pre-evacuation is provided on the surface separating the sample chamber and the exchange chamber, and the degree of vacuum of the sample chamber is used for pre-evacuation of the exchange chamber. Configured to do so. At the same time, the pre-exhaust hole, sample exchange hole, and air leak hole in the exchange chamber can be opened and closed by a series of operations using a single handle.

[0007]

By using the vacuum of the sample chamber for the preliminary exhaust of the exchange chamber, the rotary pump for the preliminary exhaust or the exhaust pipe from the rotary pump becomes unnecessary. Further, when the sample chamber is in a low vacuum state, a vacuum gauge for measuring and adjusting the degree of vacuum in the exchange chamber, a needle valve, an adjusting circuit, etc. are not necessary. In addition, by constructing a valve that can perform pre-evacuation and air leak conditions in the exchange chamber with a series of operations using a single handle, the air leak valve and the like are no longer required, and the functionality does not deteriorate compared to conventional devices, and the cost is reduced. An advantageous scanning electron microscope can be provided.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A longitudinal section of a sample exchange chamber in an embodiment of a scanning electron microscope constructed according to the present invention is shown in FIG. 1, and an AA section of FIG. 1 is shown in FIG. An exchange base 6 having an exchange hole 3 for connecting the sample chamber and the sample exchange chamber 3 and a preliminary exhaust hole 4 between the sample chamber and the sample exchange chamber 2 and an air leak hole 5 for connecting the sample exchange chamber and the atmosphere. And a rotary valve 8 rotatable around the rotary shaft 7 with an O-ring 17 interposed around each hole. By rotating this rotary valve with the rotary handle 13, the exchange window 9 on the rotary valve can pass through the preliminary exhaust position 10 and rotate to the air leak position 11. In addition, the diameter of the pre-evacuation hole affects the change in the degree of vacuum in the sample chamber during pre-evacuation depending on the volume ratio of the sample chamber and the sample exchange chamber, etc. The diameter should be Alternatively, when the degree of vacuum in the sample chamber is high or low, the diameter can be exchanged or changed according to the diameter.

The sample replacement method is as follows:
6 is pulled back to the exchange chamber with the exchange rod 12, the rotary handle is turned clockwise, and when the exchange window is at the air leak position, the exchange chamber is leaked, and the exchange port 14 is removed to perform sample exchange. A new sample is set in the exchange chamber, the rotary handle is rotated counterclockwise to the pre-evacuation position, waits for several seconds to 10 seconds, and then rotated to the exchange position to insert the sample into the sample chamber.

As described above, the sample exchange using the sample exchange chamber can be performed in a short time with a simple operation, and the rotary pump dedicated to the preliminary exhaust or the exhaust pipe 31 and the valve 25 for switching the rotary pump, Since the vacuum gauge 19, the air leak valve 24, the needle valve 22 and the like are unnecessary, it is very effective in terms of cost. In addition, it is possible to realize large samples at a low cost by enlarging the exchange chamber.

In this embodiment, the rotary valve is used for explanation, but the vacuum of the sample chamber can be used for preliminary evacuation even with other valve systems such as a gate valve. Further, in the scanning electron microscope capable of observing both the high vacuum state and the low vacuum state, even during the high vacuum observation, the sample chamber is temporarily switched to the low vacuum state by the signal of the microswitch 15 or the like during the sample exchange, and after the sample exchange, By configuring to return to the high vacuum state again, it is possible to exchange samples for both high vacuum and low vacuum.

[0012]

Since the present invention is constructed as described above, it has the following effects.

By providing a hole for pre-evacuation between the sample chamber and the exchange chamber and using the vacuum of the sample chamber for pre-evacuation of the exchange chamber, the rotary pump for the pre-evacuation required for the conventional sample exchange becomes unnecessary. Moreover, a solenoid valve, a vacuum gauge, etc., which accompany the sequence of preliminary evacuation, are not required. Therefore, the cost can be significantly reduced. In particular, it is possible to replace the sample using the replacement chamber when the sample chamber is in a low vacuum state, which requires much cost in the conventional method, with a simple operation and a very short time. Therefore, many samples can be rapidly observed within a short period of time, and the electron gun section is always kept in a high vacuum state, so that a long life of the filament can be expected.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a block diagram showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sample chamber, 2 ... Sample exchange chamber, 3 ... Exchange hole, 4 ... Pre-evacuation hole, 5 ... Air leak hole, 6 ... Exchange base, 7 ...
Rotary shaft, 8 ... rotary valve, 9 ... exchange window, 12 ... exchange rod,
14 ... Exchange port, 16 ... Sample, 17 ... O-ring.

Claims (3)

[Claims] 1. A scanning electron microscope equipped with an orifice below an electron lens so that only the sample chamber can be observed in a low vacuum state, and the sample in a sample exchange chamber provided adjacent to the sample chamber. A scanning electron microscope, wherein a hole for pre-evacuation is provided on a surface separating the chamber and the sample exchange chamber, and the vacuum of the sample chamber is used for pre-evacuation of the sample exchange chamber. 2. The preliminary exhaust hole according to claim 1,
A scanning electron microscope in which a hole for sample exchange and a hole for leaking air in the exchange chamber can be opened and closed by a series of operations of a single handle. 3. The scanning electron microscope according to claim 1, wherein when the sample chamber is in a high vacuum state, the sample chamber is automatically switched to a low vacuum by a micro switch linked with the operation of the sample exchange chamber.