JPS59143249A - Scanning type electron microscope - Google Patents

Abstract

PURPOSE:To obtain a scanning type electron microscope which can realize plasma etching of a sample within a sample chamber by providing a reaction gas introducing tube from which a reaction gas plasma is sprayed to the sample on a sample board and an exhaust tube which is coupled to an exhaustion pump and from which the reaction gas is exhausted outside the sample chamber. CONSTITUTION:A reaction gas in the reaction gas bombe B is an oxygen gas or a mixture of oxygen gas and carbon tetrafluoride gas. When this gas passes between electrode pair e, e of plasma generating part P, a high frequency voltage is applied and thereby the gas changes into plasma. The reaction gas plasma passes a reaction gas introducing tube 2 and is then sprayed to a sample 5 on a sample board 4 from the aperture thereof. The atoms and molecules at the surface of sample 5 are blown off for etching. The reaction gas sprayed from the reaction gas introducing tube 2 and atoms, molecules blown off by this reaction gas are fetched from the aperture of reaction gas exhausting tube 3 and then exhausted outside the sample chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scanning electron microscope, and more particularly to a scanning electron microscope capable of plasma etching a sample within a sample chamber.

In recent years, it has become common to observe biological samples and the like using a scanning electron microscope. This is because observation with a scanning electron microscope is an observation of the surface of a sample, and the sample can be left as a bulk, making it easier to correlate the observed image with an optical microscope. Additionally, the image capture depth is deep, making it suitable for observing three-dimensional samples.

When preparing a living body sample and observing its interior, it is necessary to expose the part of the sample to be observed. For this reason, there is a method of cutting the sample with a razor, etc., but when the cut surface is observed under a microscope, it is found that the sample has been crushed or scratched by the cutter, which is not appropriate.

Therefore, the surface of the sample is etched using a plasma etching method, the interior of the sample is exposed to the surface, and this surface is observed. In this method, plasma-formed reactive gas is caused to collide with the surface of the sample, thereby repelling atoms and molecules on the surface of the sample, thereby gradually scraping away the surface of the sample and exposing the interior.

However, since this plasma etching device is generally a separate device from the scanning electron microscope, in order to etch the sample to the desired degree, the sample must be etched little by little, and the degree of etching must be adjusted. They observed it with a scanning electron microscope, and repeated etching and observation until the etching was adequate. In this method, the sample is repositioned on the sample stage of the scanning electron microscope each time it is etched, so there is an error in the placement, making it extremely difficult to observe the same field of view. In addition, with this method, it takes time to actually observe the sample after etching, so the surface of the sample may change during that time, or the surface may be damaged due to shock during movement. There was a problem in that the fine structure was destroyed, making it difficult to observe the exact state of the sample.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a scanning electron microscope capable of plasma etching a sample within a sample chamber.

In order to achieve the above object, the present invention has a plasma generator installed in a sample chamber of a scanning electron microscope, and a sample stage that is connected to the plasma generator and has a reactive gas turned into plasma by the plasma generator. The main feature is that the reactor gas inlet pipe is provided with a reactant gas inlet pipe that sprays the reactant gas toward the upper sample, and a reactant gas exhaust pipe that is connected to an exhaust pump and discharges the reactant gas to the outside of the sample chamber. Optimally for feeding the reaction gas, the reaction gas inlet pipe and the discharge pipe should open facing each other with the sample in between. Then, the reaction scum hits the sample from the reaction gas introduction tube and is sucked into the discharge tube, so that the sample chamber is hardly filled.

In addition to the above configuration, the sample chamber also includes a barrier gluo t, 1
．． 0 skin yah, -0, yo. 0, oh.

It is possible to block the scattering of gas particles and protect the objective lens, etc.

The present invention will be described in detail below based on the drawings.

FIG. 1 shows an embodiment of the first invention of the present application. In this embodiment, a plasma generator 1 is attached to a sample chamber S of a scanning electron microscope. This plasma generation device consists of a high frequency power source H, a matching network M, and a plasma generation section P. The plasma generating part P is formed of a cylinder made of quartz glass, and a pair of electrodes is provided on the outer periphery of the cylinder.A high-frequency voltage from a high-frequency power supply H and a matching network M is applied to the electrode pairs e and e. is added. A reaction gas pump B is connected to the plasma generation section P via a pulp 9. A reaction gas introduction pipe 2 made of a material with high anti-glare properties such as stoneware glass is connected to the side opposite to the side connected to the reaction gas cylinder B of this plasma generation part P, and this reaction gas introduction tube 2 is connected to the side opposite to the side connected to the reaction gas cylinder B. The tube 2 is provided protrudingly into the sample chamber S of the scanning electron microscope. The connection between the sample chamber S and the reaction gas introduction tube 2 is sealed with an O-ring or the like to prevent the vacuum in the sample chamber S from being broken. The tip of the reaction gas introduction tube 2 on the sample chamber S side is open toward the sample 5 near the sample 5 on the sample stage 4 installed in the sample chamber S.
The tip is constricted into a substantially conical shape to form a nozzle structure, and sample 5
The reactant gas is efficiently blown onto the reactor. The reaction gas discharge pipe 3 is disposed opposite to the opening of the reaction gas introduction pipe 2 with the sample 5 interposed therebetween, and is open. This reactive gas exhaust pipe 3 is made of quartz glass like the reactive gas inlet pipe 2, and extends from the vicinity of the sample 5 in the sample chamber S to the outside of the sample chamber S. In this case as well, the connection to the sample chamber S is sealed with a QIJ ring, similar to the reaction gas introduction tube. An exhaust bonder E is connected to the end of the reaction gas exhaust pipe 3 outside the sample chamber S. As the exhaust pump E, an oil rotary pump or the like that can perform high vacuum suction is used.

The reactant gas in the reactant gas cylinder B is oxygen gas or a mixture of oxygen gas and carbon tetra7tide gas, etc. between the electrode pair of the plasma generating part P! When passing through t, a high frequency voltage is applied to it and it enters a plasma state. This reactive gas in a plasma state passes through the reactive gas introduction tube 2 and is blown onto the sample 5 on the sample stage 4 from its opening.

The sample 5 is, for example, a biological braid, but when a reactive gas turned into plasma is blown onto the surface of the sample 5, atoms and molecules on the surface of the sample 5 are repelled and etched. Then, as time passes, the surface of the sample is gradually scraped away to expose the inside. While this reaction gas introduction pipe 2 is blowing out the reaction gas, the discharge pump E connected to the reaction gas discharge pipe 3 is operated, and the reaction gas blown out from the reaction gas introduction pipe 2 and this reaction gas are The atoms and molecules blown away are taken in from the mouth of the reaction gas discharge pipe 3υ1] and are discharged to the outside of the sample chamber.

FIG. 2 shows an embodiment of the second invention of the present application. In this embodiment, a plasma generator 1, a reactive gas inlet pipe 2, a reactive gas exhaust pipe 3, and a barrier pull leak pulp 6 are installed in a sample chamber S of a scanning electron microscope.

The configurations of the plasma generator 1, the reactive gas inlet pipe 2, and the reactive gas exhaust pipe 3 are similar to the respective members in the first invention described above. In the present invention, a barrier pull leak pulp 6 is provided on the wall surface of the sample chamber S of the scanning electron microscope, so that outside air or an inert gas can be introduced into the sample chamber S.

The introduction of outside air or an inert gas is carried out when performing plasma etching. At this time, the gas pressure in each part is P2, the gas pressure in the reaction gas introduction pipe 2 is P2, and the reaction gas discharge pipe 3 is P2.
When the gas pressure inside the sample chamber S is PS and the gas pressure inside the sample chamber S is Ps, outside air or an inert gas is introduced into the sample chamber S using the barrier pull leak pulp 6 so that the relationship PS>P2>PS is established. In this way, as shown in FIG. 3, the reaction gas blown out from the reaction gas introduction pipe 2 is replaced by the outside air or inert gas introduced into the sample chamber when it is blown into the reaction gas discharge pipe 3. Since the reaction gas is discharged in such a way that it is enveloped in the sample chamber, the reaction gas is not scattered in the sample chamber, and is all sucked into the reaction gas exhaust pipe 3.

FIG. 4 shows an embodiment of the third invention of the present application. In this embodiment, a movable shaft 1 is provided in the sample chamber of the scanning electron microscope between a plasma generator 1, a reactive gas inlet tube 2, a reactive gas exhaust tube 3, a sample stage 4, and an objective lens 10. It is. In the present invention, the sample table 4 and the objective lens 1o of the sample chamber S of the scanning microscope are made of a corrosion-resistant material such as stainless steel, or the sample table 1 is made of a corrosion-resistant material, for example, or made of stainless steel by a screw operation. During the etching step 5, the objective lens 10 of the scanning electron microscope is moved to a position that shields the objective lens 10 of the scanning electron microscope from the reaction gas blown out from the reaction gas introduction tube 2.
It can be moved to a position that does not affect the path of the electron beam incident on the sample 5.

Since these inventions have the above-described configuration, plasma etching can be performed without corroding parts other than the sample when etching the sample in the sample chamber of the scanning electron g-micrometer. Etching and observation can be repeated on the same sample stage, making it easy to observe the sample while checking the degree of etching in the same field of view. This has the effect that the sample can be observed accurately because the fine structure is not destroyed by shock or the like.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a scanning electron microscope according to an embodiment of the first invention, FIG. 2 is a sectional view showing a scanning electron microscope according to an embodiment of the second invention, and FIG. FIG. 4 is an explanatory diagram showing the flow of gas near the sample stage of the scanning electron microscope shown in FIG. 1... Plasma generator 2... Reaction gas introduction pipe 3
... Reaction gas discharge pipe 4 ... Sample stage patent applicant
Akashi Seisakusho Co., Ltd. Procedural Amendments Showa R5 Last March 29th Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of the case 1982 Patent Application No. 17490 2, Title of the invention Scanning electron microscope 3, Person making the amendment Related Patent Applicant Name: Akashi Seisakusho Co., Ltd. 4, Agent Address: 105 Telephone: 580-8931-6,
Number of inventions increased by the amendment 7. Contents of the amendment in the "Detailed Description of the Invention" column of the specification subject to the amendment 1) The description of "infused" in the additional line on page 9 of the specification cylinder was changed to "
It gets sucked in,” he corrected.

Claims (1)

[Scope of Claims] 1) A plasma generator is attached to the sample chamber of a scanning electron microscope, and the sample chamber is connected to the plasma generator to direct a reaction gas turned into plasma by the plasma generator toward the sample on the sample stage. It is characterized by being completely equipped with a reaction gas inlet pipe for spraying the reaction gas and a reaction gas exhaust pipe connected to an exhaust pump and discharging the reaction gas to the outside of the sample chamber, so that the entire plasma etching process can be performed on the sample inside the sample chamber. scanning electron microscope. 2) A plasma generator is installed in the sample chamber of the scanning electron microscope, and a reactive gas inlet tube is connected to the plasma device in the sample chamber and blows the reactive gas turned into plasma by the plasma generator toward the sample on the sample stage. and a barrier leak pulp that is connected to an exhaust pump and discharges and introduces the reaction gas outside the sample chamber, thereby making it possible to perform plasma etching on a sample within the sample chamber. 3) A plasma generator is attached to the sample chamber of the scanning electron microscope, and a reactive gas is introduced into the sample chamber, which is connected to the plasma generator and sprays the reactive gas turned into plasma by the plasma generator toward the sample on the sample stage. A reaction gas exhaust pipe connected to an exhaust pump and discharging the reaction gas outside the sample chamber, and a movable shutter installed between the sample stage and the objective lens, are equipped with a movable shutter installed between the sample stage and the objective lens. A scanning electron microscope characterized by being able to perform etching processing.