JPH1167133A - Environment control type scanning electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constant humidity environment inside a sample chamber for a long time by providing a circulating water pipeline for maintaining the inside of a sample chamber at a constant temperature, and dividing the water in the circulating water pipeline, and controlling the water so as to be supplied in a minute quantity into the sample chamber. SOLUTION: A circulating water pipeline 7, of which one end is arranged in a circulating pump 9 and of which the other end is arranged in a constant temperature over 10, supplied the water adjusted at the constant temperature. A bypass tube 2 divides the water flowing in the circulating water pipeline 7, and a needle valve 3 throttles the quantity of the water flowing in from the bypass tube 2, so as to adjust the quantity of the water to be supplied to a capillary tube 4 and obtain a predetermined low vacuum atmosphere inside a sample chamber 8. This flow adjustment may be manual or automatic. As the capillary tube 4, a capillary tube of stainless steel having flexibility is used so as to follow up the movement of a sample base 6, and a dedicated moving mechanism is not especially provided. With this structure, water-supplying speed is controlled at 0.1-10 μl per second over a long time, and supplying of water is unnecessary, and the structure of a device is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro-injection apparatus used for an environmentally controlled scanning electron microscope (hereinafter, referred to as ESEM).

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for observing various substances under various environmental controls. In particular, there is a demand that a constant amount of water be supplied to a sample for a long time and that the reaction be observed over several hours. In contrast,
Conventionally, an apparatus for supplying a small amount of liquid to a sample as shown in FIG. 3 has been used.

FIG. 3 is a top view showing the configuration of a conventional micro water injection device for ESEM. The micro-water injection device main body 21 is attached to the sample chamber, and can supply a liquid such as water to the sample and determine the injection position thereof by an external operation. The liquid stored in the syringe 22 is pushed into the cylinder, and the sample 26 on the sample table 27 is passed through the introduction pipe 24 and the injection needle 25.
Supplied to Since the tip of the injection needle 25 is not in contact with the sample, the liquid is supplied by dropping the droplet.

[0004] The injection needle 25 can be moved in a three-dimensional direction by a moving mechanism 23 provided on the micro-injection device main body 21.
The tip of the injection needle 25 can be positioned.
The introduction pipe 24 and the injection needle 25 are in the form of a cantilever fixed to the moving mechanism 23 through the wall of the sample chamber on the liquid inlet side of the introduction pipe 24.

[0005]

In the above-mentioned prior art, it was possible to supply the liquid to an arbitrary place on the sample, but a certain amount of liquid was applied to the entire observation surface of the sample for a long time. It was extremely difficult to supply. This is because the liquid supplied from the tip of the injection needle 25 becomes a large droplet due to surface tension and is dropped on the sample at one time.

Since the amount of liquid in the syringe 22 is naturally limited, in order to continue supplying the liquid for a long time, the liquid must be replenished into the syringe 22 from time to time. It was a cumbersome operation for the operator. Also,
In the micro water injection device shown in FIG. 3, the moving mechanism 23 must be provided, and the device itself has a complicated structure.
With the movement of the sample 26 or the sample table 27, it was necessary to position the injection needle 25.

An object of the present invention is to provide an ESEM which can supply a small amount of water to a sample while controlling it with high precision and can keep the sample chamber in a constant atmosphere for a long time.

[0008]

In order to solve the above-mentioned problems, an ESEM of the present invention comprises a circulating water pipe for maintaining the inside of a sample chamber at a constant temperature, and a method for branching the water in the circulating water pipe so as to sample the sample. A micro-injection device for supplying a small amount into the chamber and maintaining the sample chamber in a low vacuum atmosphere.

[0009]

According to the ESEM of the present invention, a constant amount of water can be stably supplied to a sample for a long time. The supplied water is water in a circulating water pipe for maintaining a constant temperature in the sample chamber. Since the micro-injection device can be mounted on the wall or the door of the sample chamber, the mounting location can be selected so as to be suitable for the shape and size of the detector and other structures inside the sample chamber.

Hereinafter, an ESEM according to the present invention will be described with reference to FIGS. FIG. 1 shows an ES according to the present invention.
It is a top view for showing the composition of the micro water injection device of EM.
The micro-injection apparatus 1 includes a bypass pipe 2 for branching and flowing water flowing in a circulating water pipe 7, a needle valve 3 connected to the bypass pipe 2 for controlling water output, and a sample table 6 connected to the needle valve 3. And a thin tube 4 for supplying controlled water. That is, the water in the circulating water pipe 7 is supplied to the sample table 6 via the bypass pipe 2, the needle valve 3, and the thin tube 4 in order, and finally, the sample 5 held on the sample table 6 is lowered to a predetermined low level. Keep in a vacuum atmosphere.

One end of the circulating water pipe 7 has a circulating pump 9.
The other end of the circulating water pipe 7 is supplied with water adjusted to a constant temperature at the outlet side of the circulating water pipe 7. The circulating water pipe 7 is mounted inside the sample chamber 8 in FIG. 1, but is not limited to this, and a stage (not shown) on which the sample table 6 is mounted may be mounted outside the sample chamber. It may be attached to. The stage includes a heat-retention stage for preventing a decrease in the sample temperature due to adiabatic expansion that occurs when water is introduced into a low-vacuum sample chamber, and an XY for changing the observation position of the sample.
There are stages and the like, and circulating water piping attached to these stages is also an object of the present invention.

Since the bypass pipe 2 branches a small amount of water flowing through the circulating water pipe 7, it is preferable that the inner diameter of the bypass pipe 2 is smaller than the inner diameter of the circulating water pipe 7. Further, the branch of the water may be at any place of the circulating water pipe 7, but it is more preferable to be near the circulating pump 9 where the water temperature is kept constant. The needle valve 3 regulates the amount of water supplied to the thin tube 4 by narrowing the amount of water entering from the bypass tube 2. That is, the inside of the sample chamber 8 is adjusted to a predetermined low vacuum atmosphere in consideration of the fluctuation of the water pressure on the inlet side of the needle valve 3. This water amount adjustment may be manual or automatic.
In the case of auto, a motor (not shown) connected to the needle valve 3 and a parameter input device (not shown) for controlling the driving of the motor are used.

The thin tube 4 finally guides the water whose amount has been adjusted to the sample stage 6. The thin tube 4 has flexibility so as to follow the movement of the sample stage 6. For example, outer diameter 0.3mm, inner diameter 0.1
5 mm stainless steel is used. Therefore, there is no need to provide a moving mechanism. By controlling the needle valve 3 manually or automatically using the micro water injection device having the above configuration, the water supply rate could be controlled at 0.1 to 10 μl per second.

FIG. 2 is a sectional view showing the structure of a sample table attached to the ESEM of the present invention. The sample table 6 is a container in which the sleeve 11 and the hygroscopic material 12 are contained,
Is supplied to supply water to the hygroscopic material 12. The water supplied from the thin tube 4 is absorbed by the hygroscopic material 12. Any material may be used as the hygroscopic material 12 as long as it can easily absorb liquid, and for example, a filter paper, a woven or nonwoven fabric made of ultrafine polymer fibers is used.

The sleeve 11 is, for example, stainless steel having an outer diameter of 4 mm, an inner diameter of 3 mm, and a length of 5 mm. A sample 5 to be observed is packed in the sleeve 11, an upper surface thereof is irradiated with an electron beam, and a lower surface thereof is in contact with a hygroscopic material 12. The water once absorbed by the hygroscopic material 12 is diffused into the sample stage 7 by evaporation. In the case where the sample 13 is powdery, fibrous, or porous, water diffuses inside the sample stage 6 and also passes through the inside of the sample due to capillary action and reaches the observation surface (top surface) of the sample. In the case of a sample in which water cannot pass through the inside, the water may rise through a gap between the sample 13 and the sleeve 11 by capillary action and reach the observation surface of the sample.

In any case, it is important that the amount of liquid lost from the moisture absorbent 12 due to evaporation or capillary action and the amount of liquid supplied to the moisture absorbent 12 are balanced so that a constant humidity atmosphere is always maintained.

[0017]

As described above, according to the ESEM of the present invention, the circulating water pipe is branched out by the micro-injection device, and a small amount of water is taken out. Can supply. Water is removed from the circulating water piping and does not need to be replenished. Further, since there is no need to provide a moving mechanism in the micro water injection device, the structure of the device can be simplified.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a micro water injection device of an ESEM according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure of a sample stage of the ESEM according to the embodiment of the present invention.

FIG. 3 is a plan view showing the configuration of a conventional ESEM micro-injection apparatus.

[Explanation of symbols]

 1 ············································································································ ... Sample 6 ... Sample table 7 ... Circulating water piping 8 ... Sample chamber 9 ... Circulating pump 10 ······························································································ 23 ····· Moving mechanism

Claims (1)

[Claims] 1. A vacuum chamber forming a passage for an electron beam emitted from an electron beam source, connected to the vacuum chamber via a pressure limiting opening, and maintained at a constant temperature and supplied with water to provide a low vacuum. A sample chamber held in an atmosphere, an electron optical system for focusing and scanning the electron beam on the sample through the pressure limiting opening, and a secondary electron detector for detecting gas-amplified secondary electrons generated from the sample A circulating water pipe for maintaining the inside of the sample chamber at a constant temperature, and branching the water in the circulating water pipe and supplying a small amount of water into the sample chamber. An environment-controlled scanning microscope, comprising: a small amount water injection device for maintaining a room in a low vacuum atmosphere.