JP2005222748A - A focused ion beam device with an exhaust pipe in the chamber. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focused ion beam apparatus with high processing accuracy, which prevents discharge by efficiently exhausting gas, makes it difficult for fluctuations in focus and irradiation position to occur.
SOLUTION: An exhaust pipe 9 for exhausting gas is provided in the vicinity of an end of a lens barrel 5 arranged at the center in a chamber 6 so that its tube port faces a sample. In this case, an exhaust pipe 9 is provided at a position facing the gas injector 8 around the ion beam axis of the ion beam column 5. Alternatively, the supply / exhaust pipe 16 is provided adjacent to the gas supply port 10 of the gas supply / exhaust pipe 16 so that the exhaust port 11 comes. The exhaust port 11 has a temperature adjusting function for heating and cooling.
[Selection] Figure 1

Description

  The present invention relates to a focused ion beam apparatus that processes a sample using a gas.

Conventionally, in a FIB apparatus provided with a deposition gas and an etching gas injector for processing a sample, the residual gas after the processing has been exhausted from an exhaust port of a chamber wall surface (see, for example, Non-Patent Document 1). FIG. 4 shows a conventional exhaust system in a focused ion beam apparatus provided with an ion beam column 57. In the chamber 52, gas is supplied to the sample on the processing sample mounting portion 53 and spreads in the chamber. The gas is exhausted from the wall exhaust port 55 through the exhaust pump 56.
Shinji Nagamachi, Masahiro Ueda, Junzo Ishikawa “Thin Film Formation with Low Energy Focused Ion Beams” Surface Science vol16, No12, p724-728, 1995 (Fig. 4).

  In the conventional focused ion beam apparatus, since the exhaust port is in the chamber wall surface, the residual gas is exhausted after diffusing to the chamber inner wall. In this case, since diffusion occurs in all directions, a part of the residual gas diffuses to the lens portion of the lens barrel that generates the ion beam. The electrostatic lens portion of the lens barrel uses an ion beam accelerated at a voltage of 20 to 30 kV, and when focusing, a high voltage of 20 to 35 kV is applied to the electrostatic lens portion. When the residual gas enters the lens barrel, there is a problem in that the dielectric breakdown voltage is deteriorated in the electrostatic lens portion and discharge is easily generated. When the electric discharge occurs, the electric field environment generated by the electrostatic lens changes, so that the focal point and the irradiation position change, resulting in a decrease in processing accuracy.

  It is an object of the present invention to provide a focused ion beam apparatus that solves the above problems and prevents the occurrence of the discharge, thereby making it difficult for the focal point and the irradiation position to fluctuate and improving the processing accuracy.

  In order to solve the above-described problems, in the FIB apparatus of the present invention, an exhaust pipe for gas exhaust is provided in the vicinity of the end of the lens barrel disposed in the center of the chamber so that the tube port faces the sample. In this case, an exhaust pipe is provided at a position facing the gas injector with the ion beam axis of the ion beam column as the center. Alternatively, an exhaust pipe is provided adjacent to the gas supply port of the gas injector so that the exhaust port comes. These exhaust pipes have a temperature adjusting function for heating and cooling the exhaust port.

  The present invention has the following effects.

1． Provide an exhaust pipe with the exhaust port facing the sample stage at the position facing the gas injector around the ion beam axis, or exhaust toward the sample stage and adjacent to the gas supply port of the gas injector By providing the exhaust pipe so that the mouth comes, a part of the residual gas can be removed before diffusing. As a result, the amount of residual gas reaching the lens barrel is reduced, and the amount of gas reaching the electrostatic lens inside the lens barrel is also reduced. Therefore, it is possible to reduce the residual gas being ionized and decomposed by the high voltage of the electrostatic lens and being discharged by the electrostatic lens. Since the discharge phenomenon is reduced, the ion beam axis is stabilized and the machining accuracy is improved.

2. By providing the exhaust pipe with a temperature adjustment function, gas is adsorbed to the exhaust pipe during cooling, and gas is desorbed from the exhaust pipe during heating. The desorbed gas is exhausted from the exhaust pipe. The gas can be efficiently exhausted by the function of trapping the gas and desorbing the trapped gas without processing.

Residual gas after focused ion beam processing is exhausted from the gas supplied from the gas supply port of the gas injector through the exhaust port of the exhaust pipe. The generation of discharge is reduced by exhausting a part of the residual gas causing the discharge before reaching the lens of the lens barrel from the chamber. Further, by removing a part of the residual gas before diffusing inside the chamber, gas adhesion contamination on the inner wall of the chamber can be reduced. In addition, a cooling and heating mechanism is provided as the one having an exhaust pipe temperature control function. By cooling the exhaust pipe, the residual gas can be efficiently adsorbed on the exhaust pipe, and by heating the exhaust pipe, the gas adsorbed on the exhaust pipe can be efficiently desorbed and exhausted.
Embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are schematic views of an FIB apparatus with an exhaust pipe according to the present invention. In FIG. 1, a gas supply pipe 8 and a gas exhaust pipe 9 are attached to a chamber 6 with its opening directed to a portion of the sample stage where the sample is placed. The gas exhaust pipe 9 is provided to face the gas supply pipe with respect to the ion beam axis. The gas exhaust pipe 9, the gas supply / exhaust pipe 16, the wall exhaust port 7, and the wall exhaust port 15 of FIGS. 1 and 2 are connected to an exhaust pump. At this time, if the gas exhaust pipe 9 in FIG. 1 is provided at a position symmetrical to the gas supply pipe 8 with respect to the ion beam axis, the exhaust can be performed more efficiently. In the chamber 6 of FIG. 1, there is a processing sample mounting portion 3 on a sample stage 4, and an ion beam is generated immediately above it, and a focused ion beam mirror that focuses and scans the ion beam on the sample. There is a tube 5. Gas is supplied into the chamber 6 from the gas supply port 1 in FIG. 1, and the gas spreads on the processing sample mounting portion 3. The chamber 6 has a wall surface exhaust port portion 7 for exhausting the residual gas. However, a part of the residual gas is exhausted from the gas exhaust port 2 provided in the chamber 6 before diffusing to the lens barrel 5 and the wall surface exhaust port 7. Inside the tip of the gas exhaust port 2 is a cooling mechanism for trapping the gas in a liquid or solid state, and a heating mechanism for re-gasifying and desorbing the liquid or solid gas component, that is, a temperature management mechanism Is equipped. As the gas heating mechanism cools the gas exhaust port 2 and continues to adsorb the gas, the adsorption capacity declines, so the gas exhaust port 2 is heated periodically to desorb the adsorbed gas, and the adsorption capacity It is for recovering. FIG. 3 shows the temperature adjustment mechanism for cooling and heating at the exhaust port. A cooling pipe 18 through which a liquid for cooling the exhaust pipe flows and a heating wire heater 19 for heating the exhaust pipe are provided inside the exhaust opening 2 and the exhaust opening 11 in FIGS. Thus, by reducing the residual gas diffusing into the electrostatic lens of the lens barrel 5 and the lens barrel 17 in FIGS. 1 and 2, the discharge in the lens barrel is reduced. Since the gas component becomes a molecular flow especially under high vacuum, if the gas supply port 1 and the gas exhaust port 2 are arranged facing each other as shown in Fig. 1, the supplied gas component takes a straight orbit and the sample Since it is reflected by the table and exhausted from the exhaust port 2, the gas exhaust effect is high.

  In FIG. 2, a gas supply / exhaust pipe 16 having a gas supply port 10 and a gas exhaust port 11 is attached to a chamber 12. The gas supply port portion 10 and the gas exhaust port portion 11 are provided side by side and integrated.

  Since the gas supply pipe and the gas exhaust pipe are integrated, the chamber 12 can be compactly accommodated. The chamber 12 has a processing sample mounting portion 13 on a sample stage 14, and a lens barrel 17 for generating an ion beam is provided immediately above the processing sample mounting portion 13. Gas is supplied into the chamber 12 from the gas supply port 10 in FIG. 2, and the gas spreads on the processing sample mounting portion 13. Since the gas exhaust port portion 11 is provided adjacent to the gas supply port portion 10, a part of the residual gas is exhausted from the exhaust port portion 11 before diffusing into the wall surface exhaust port 15 and the lens barrel 17. At this time, the gas exhaust port 11 is provided with the cooling mechanism for trapping the gas in a liquid and solid state and the heating mechanism for desorbing the liquid and the solid gas. In this way, a part of the residual gas is exhausted from the gas exhaust port 11 for exhausting before diffusing into the lens barrel 17, so that discharge in the lens barrel can be reduced.

It is a schematic diagram of the focused ion beam apparatus which attached the exhaust pipe by this invention. It is a schematic diagram of the focused ion beam apparatus which attached the exhaust pipe by this invention. It is a schematic diagram of the temperature control mechanism of cooling and heating in an exhaust port part. It is a figure which shows the conventional exhaust system in a focused ion beam apparatus.

Explanation of symbols

1 Gas supply port
2 Gas exhaust port
3 Sample mounting part for processing
4 Sample stage
5 Lens tube
6 chambers
7 Wall exhaust
8 Gas supply pipe
9 Gas exhaust pipe
10 Gas supply port
11 Gas exhaust port
12 chambers
13 Sample mounting part for processing
14 Sample table
15 Wall exhaust
16 Gas supply / exhaust pipe
17 Lens tube
18 Cooling pipe
19 Heating wire
20 Exhaust vent

Claims (4)

  In a focused ion beam device equipped with a gas injector that supplies a deposition gas and an etching gas for processing a sample to the surface of the sample, an ion exhaust pipe that collects and exhausts the residual gas from the processing inside the chamber A focused ion beam device provided at a position facing the gas injector with respect to an ion beam axis of the system.   In a focused ion beam apparatus provided with a gas injector for supplying a deposition gas and an etching gas for processing a sample to the surface of the sample, an exhaust port of an exhaust pipe for collecting and exhausting the processed residual gas inside the chamber A focused ion beam apparatus characterized in that a part is attached adjacent to the supply port of the gas injector.   3. The focused ion beam apparatus according to claim 1, further comprising a trap mechanism for trapping the residual gas in the vicinity of the exhaust port.   The focused ion beam apparatus according to claim 3, wherein the trap mechanism is a temperature adjusting mechanism that cools and heats the exhaust port.

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