JPH0550647U - Marking device for scanning electron microscope - Google Patents

Abstract

(57) [Summary] [Construction] In order to inject a hydrocarbon gas to the sample 4 which is statically placed in the vacuum chamber 1 of the scanning electron microscope which obtains an image by scanning the surface of the sample with the electron beam 11, Is provided with a nozzle 6 connected to the hydrocarbon gas cylinder 5. [Effect] By injecting a small amount of hydrocarbon gas onto the sample 4 in the vacuum chamber 1 and scanning the electron beam 11, the hydrocarbon gas is adsorbed on the sample surface. Since carbon has a smaller amount of secondary electron generation than metal, the position scanned by the electron beam 11 is used as a marking by making it appear darker than the unirradiated part, and the accuracy of the electron beam irradiation system 10 of the scanning electron microscope is improved. Highly accurate marking is possible in proportion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a highly accurate marking device applied to a sample surface of a scanning electron microscope.

[0002]

[Prior Art]

 Conventionally, a sample of a scanning electron microscope has been marked for confirming an observation position and for use as a scale. For example, the method was to scratch the sample surface with a needle or a blade or to apply a very small amount of paint to the sample surface before placing the sample on a scanning electron microscope. However, since these methods are carried out manually, the accuracy was about several tens of μm.

[0003]

[Problems to be solved by the device]

 However, since the resolution of the scanning electron microscope is several nm, a marking method with higher accuracy than the conventional marking method was necessary for observing details under high magnification.

In view of this, the present invention proposes that the adsorbed layer in which contaminants such as oil vapor of an oil diffusion pump suspended in the vacuum chamber of a scanning electron microscope are decomposed by an electron beam, carbonized and adsorbed on the sample surface, is displayed. The purpose is to use for marking what appears darker than the unilluminated area above. That is, an object of the present invention is to provide a marking device for a scanning electron microscope with an accuracy of several tens nm or less by adjusting the degree of vacuum in the sample chamber and the components of floating gas and irradiating with an electron beam.

[0005]

[Means for Solving the Problems]

 The marking device for a scanning electron microscope of the present invention is a marking device for a scanning electron microscope, which performs marking on the surface of a sample, which is placed in a vacuum chamber of a scanning electron microscope which scans a focused electron beam on the surface of the sample to obtain an image. It is characterized in that a nozzle that is connected to a hydrocarbon gas cylinder and injects gas is provided in the chamber.

[0006]

[Action]

 The scanning path of the electron beam to be irradiated is set at the spot to be marked on the sample surface. Next, the valve of the gas cylinder is opened, and the hydrocarbon gas flow is sprayed onto the surface of the sample that is left stationary in the vacuum chamber of the scanning electron microscope. Then, an electron beam is scanned and the sample surface is irradiated with the electron beam. After the irradiation is completed, all the gas in the vacuum chamber is exhausted, and then normal observation is resumed. The part of the sample surface that is irradiated with the electron beam appears darker on the display than the part that is not irradiated. Therefore, it is possible to perform marking with high accuracy equivalent to the scanning accuracy of the electron beam.

[0007]

【Example】

An embodiment of the marking device for a scanning electron microscope of the present invention is shown in FIG. A stage 2 is provided in a vacuum chamber 1 of a scanning electron microscope, and a sample 4 having gold or gold-palladium, gold-platinum, or the like vacuum-deposited or sputter-coated on the surface of a sample table 3 is left stationary. Has been done. A nozzle 6 connected to a gas cylinder 5 in which a C _{10 to} C ₂₀ aliphatic hydrocarbon is enclosed is provided near the sample 4. Further, the vacuum chamber 1 is equipped with an exhaust system 9 such as an oil diffusion pump 7 and an oil rotary pump 8 because it is necessary to maintain the inside of the vacuum chamber in a high vacuum state of 10 ⁻⁵ Torr or less. In order to prevent contamination and vibration of the vacuum chamber 1 due to the exhaust system 9, a vibration isolation device, a trap, a baffle, etc. are often installed. The vacuum chamber 1 is located below the electronic scanning system 10, an electron beam 11 emitted from an electron gun (not shown) is accelerated, a scanning path is adjusted by a scanning coil 12, and the objective lens 13 is adjusted. The sample 4 is focused and irradiated by the objective diaphragm lens 14. The operation of the marking device for a scanning electron microscope according to the present invention will be described. First, the sample is set on the sample table in the vacuum chamber, and the atmosphere in the vacuum chamber 1 is exhausted to maintain a high vacuum state. Then, a normal observation is performed to determine the position where the mark indicating the observation point or the mark used as a scale is to be formed, and the scanning route of the irradiation electron beam is set for each shape. Next, the valve 15 connected to the gas cylinder 5 in which the aliphatic hydrocarbon is sealed is opened, the gas is ejected from the nozzle 6 introduced into the vacuum chamber 1, and diffuses into the vacuum chamber. Irradiate the electron beam 11. Then, on the surface of the sample irradiated with the electron beam 11, an adsorption layer of carbon, which is carbonized by the decomposition of the aliphatic hydrocarbon gas, is formed. A metal is vapor-deposited on the surface of the sample in advance, and since the amount of secondary electrons generated by the metal is larger than that of carbon, the sample surface spot scanned by the electron beam 11 appears darker than the non-irradiated spot. After the marking is completed, the pump of the exhaust system 9 is operated to exhaust the aliphatic hydrocarbon gas in the vacuum chamber 1, and then the observation is performed by a normal scanning electron microscope. The gas enclosed in the gas cylinder used in the marking device for a scanning electron microscope of the present invention is not only C _{10 to} C ₂₀ aliphatic hydrocarbons, but also diffuses in a high vacuum state and is adsorbed on the sample surface. There is no particular limitation as long as it is a hydrocarbon that is easy and not corrosive.

[0008]

[Effect of the device]

 According to the marking device for a scanning electron microscope of the present invention, a small amount of hydrocarbon gas is injected onto the sample in the vacuum chamber and the electron beam is scanned, so that the hydrocarbon gas is adsorbed on the sample surface. Since carbon has a smaller amount of secondary electron generation than metal, marking is performed by utilizing the fact that the spot where the electron beam scans appears darker than the unexposed spot, which is proportional to the accuracy of the electron beam irradiation system of the scanning electron microscope. Therefore, highly accurate marking is possible.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a marking device for a scanning electron microscope according to the present invention.

[Explanation of symbols]

 1 ... Vacuum chamber 4 ... Sample 5 ... Gas cylinder 6 ... Nozzle

Claims (1)

[Scope of utility model registration request] 1. A marking device for a scanning electron microscope for marking a sample surface, which is placed in a vacuum chamber of a scanning electron microscope which scans a sample surface with a focused electron beam to obtain an image. A marking device for a scanning electron microscope, comprising a nozzle that is connected to a gas cylinder and that ejects gas.