JP2008152941A - Ion generating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion generating device of an ion beam processing device capable of carrying out superior processing to a testpiece and shortening warm-up time of the ion beam processing device regarding the ion generating device. <P>SOLUTION: In the ion generating device of the ion beam processing device, operation of injecting a gas into an ion source 1 in a flash state in a short time for a plurality of times. As a result, a stable ion can be output and superior processing to the testpiece can be carried out. Moreover, the warm-up time of the ion beam can be shortened. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ion generator, and more particularly, an ion generator capable of performing an ion generation operation of an ion generator used in a sample preparation apparatus (SEM-CP, TEM-CP) for an electron microscope in a short time. About.

  The ion beam processing apparatus is an apparatus for performing some processing such as irradiating a sample with ions generated from an ion source to scrape the surface of the sample. In this case, ions are generated from an ion source. The ion source is provided with an emitter, and a gas such as argon gas is blown onto the emitter to ionize the gas. Further, by extracting the ions with the extraction electrode, the ions can be taken out from the ion source. . The extracted ions are irradiated onto the sample through an optical system, and subjected to processing such as ion implantation and etching.

As a conventional device of this type, a technique is known in which an ion source is brought into a plasma state and a voltage is applied to an extraction electrode to extract ions out and generate an ion beam (for example, Patent Document 1). reference). Further, a technique is known in which a part of generated ions is detected as a current, and the gas supply amount into the ionization chamber is adjusted so that the detected current amount becomes a target current value (for example, Patent Document 2). reference).
Japanese Patent Laying-Open No. 2003-338251 (paragraphs 0006 to 0008, FIG. 1) Japanese Patent Laid-Open No. 7-105892 (paragraphs 0010 to 0017, FIGS. 1 to 3)

  In the conventional ion beam processing apparatus, the ion source and the vicinity thereof are exposed to the atmosphere each time the processed sample is exchanged. For this reason, after setting the sample, the gas was drawn into the ion source at a constant flow rate after being evacuated and stabilized. In this case, the machining operation was started after 10 to 30 minutes at a constant flow rate set in advance using a needle valve or a pressure / flow rate controller.

In an ion beam processing apparatus, argon gas is injected into an ion source, and the pressure is usually used at an order of 10 ⁻³ Pa. However, the amount of argon gas injection is very small. Once the sample exchange chamber is in the atmospheric state, it is evacuated again and then the gas is injected, and it takes time (10 to 30 minutes) until the gas concentration becomes constant. Was replaced. In this case, if the gas replacement is insufficient, not only does not function as a proper ion source, it will cause an abnormal discharge, not only can significantly reduce the polishing quality of the sample, can not achieve the purpose of processing, There is a risk of ruining the sample itself.

  The present invention has been made in view of such problems, and is capable of performing excellent processing on a sample and reducing the warm-up time of the ion beam processing apparatus. The object is to provide a generator.

(1) The invention described in claim 1 is characterized in that in the ion generator of the ion beam processing apparatus, the operation of injecting the gas into the ion source is performed a plurality of times in a flash manner in a short time.
(2) The invention described in claim 2 is characterized in that the operation of injecting the gas into the ion source in a flash form is performed by turning on / off a gas solenoid valve for feeding the gas into the ion source.
(3) The invention described in claim 3 is characterized in that the cycle of the on / off operation is that the electromagnetic valve opening / closing operation of about 1 second is performed two to three times.
(4) The invention according to claim 4 is characterized in that the gas is any one of argon gas, helium gas, and nitrogen gas.

(1) According to the first aspect of the present invention, since the concentration of the gas in the ion source can be quickly set to a predetermined concentration, stable ions can be output and good processing of the sample can be performed. In addition, the warm-up time of the ion beam processing apparatus can be shortened.
(2) According to the invention described in claim 2, by turning on / off the gas solenoid valve, it is possible to perform the flash injection of the gas into the ion source.
(3) According to the third aspect of the present invention, the concentration of the gas in the ion source can be quickly set to a predetermined concentration by performing the electromagnetic valve opening / closing operation for about 1 second 2 to 3 times.
(4) According to the invention described in claim 4, it is possible to generate a good ion beam by using any one of argon gas, helium gas, and nitrogen gas as the gas to be ionized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is an ion source that emits ions, 2 is a chamber in which the sample is irradiated with an ion beam, 3 is a chamber leak electromagnetic valve for returning the interior of the chamber 2 to atmospheric pressure, and 4 is an interior of the chamber 2. A main pump (TMP) for evacuation, 5 is a solenoid valve for exhausting the chamber, 6 is a rotary pump vent valve used as a leak valve for the rotary pump, and 7 is a rotary pump (RP) for evacuation.

  8 is a flow rate regulator for adjusting the flow rate of argon gas injected into the ion source 1, 9 is an argon gas solenoid valve for injecting argon gas into the ion source 1, and 10 is a vacuum exhaust controller. For example, a CPU is used as the evacuation controller 10. The evacuation controller 10 sends a control signal to the flow rate regulator 8 to adjust the flow rate of the argon gas, as well as the vacuum pump 4, the argon gas solenoid valve 9, the chamber leak solenoid valve 3, and the chamber exhaust solenoid valve. 5. The rotary pump vent valve 6 and the rotary pump 7 are controlled. The operation of the apparatus configured as described above will be described as follows.

  A gas supplied from a cylinder (not shown) as an argon gas path passes through an argon gas electromagnetic valve 9, is adjusted to an optimum flow rate by a gas flow rate regulator 8, and is injected into the ion source 1. Now, in order to load a new processed sample, the inside of the chamber 2 is brought to atmospheric pressure. In order to make the inside of the chamber 2 atmospheric pressure, the evacuation controller 10 opens the chamber leak electromagnetic valve 3. As a result, the inside of the chamber 2 is at atmospheric pressure. When the inside of the chamber 2 is brought to atmospheric pressure and a new processed sample is set on the sample stage (not shown), the chamber leak electromagnetic valve 3 is closed under the control of the vacuum exhaust controller 10.

  Further, the evacuation controller 10 operates the evacuation main pump 4 and the rotary pump 7 to open the chamber evacuation electromagnetic valve 5 for evacuation. At this time, the rotary pump vent valve 6 is closed. In this way, the chamber 2 is evacuated.

When the degree of vacuum in the chamber 2 reaches 10 ⁻⁴ Pa, the evacuation controller 10 opens the argon gas electromagnetic valve 9 and starts to flow a specified amount of gas while controlling the flow rate regulator 8. After a certain period of time until the gas replacement is completed, a predetermined high voltage is applied to the ion source 1 to start milling.

FIG. 2 is a diagram showing a configuration example of the ion source. In the figure, 20 is an anode for emitting ions, 21 is a grid for extracting generated ions, 22 is a cathode configured to surround the grid 21, and 2 is a chamber into which ions from the ion source 1 are incident. It is. Here, the ion source 1 is filled with argon gas. When the degree of vacuum in the chamber 2 reaches about 10 ⁻⁴ Pa with the argon gas sufficiently filled, for example, a voltage of about 8 kV is applied to the anode 20, and a voltage of about 7 kV is applied to the grid 21. The potential difference between the anode 20 and the grid 21 is set to about 1 kV. As a result, the anode 20 ionizes the argon gas in contact with the anode 20 by the action of voltage. Alternatively, the inside of the ion source 1 may be in a plasma state, and argon gas may be ionized and ions may be emitted from the anode 20. In this way, the argon gas is ionized and fills in the ion source 1. The filled ions are extracted by the grid 21, pass through the opening of the grid 21 and the opening of the cathode 22, and are emitted into the chamber 2.

  Since the conventional usage method is to replace the inside of the ion source 1 with gas over about 10 to 30 minutes, it takes 10 to 30 minutes. The present invention solves this. Specifically, the present invention is used in order to speed up the gas replacement described above. In the present invention, the evacuation controller 10 sets the flow rate regulator 8 to about 100 times the optimum flow rate, and performs an operation (flushing) for turning on / off the argon gas electromagnetic valve 9 for about 1 second a plurality of times. Specifically, about 2 or 3 times is preferable. As described above, the operation of instantaneously injecting a large amount of argon gas into the ion source 1 (ON operation) and the operation of completely stopping the injection of argon gas (OFF operation) are repeated a plurality of times. In this manner, ions are emitted from the ion source 1 and the sample placed in the chamber 2 can be processed.

  By performing such an operation, the ion source 1 can be filled with a large amount of argon gas, and the gas concentration in the ion source can be set to a predetermined concentration, so that a stable ion beam is output. And good processing of the sample can be performed. Also, the ion beam warm-up time can be shortened.

  In addition, by turning on / off the gas solenoid valve, flush injection of gas into the ion source 1 can be performed. Further, by performing the electromagnetic valve opening / closing operation for about 1 second a few times, the concentration of the gas in the ion source 1 can be quickly set to a predetermined concentration, and the ion beam can be emitted quickly. Is possible.

  In the above embodiment, the case where argon gas is used as the ionizing gas is taken as an example, but the present invention is not limited to this, and other gases such as helium gas or nitrogen gas can be used. A good ion beam can be generated.

It is a block diagram which shows one embodiment of this invention. It is a figure which shows the structural example of an ion source.

Explanation of symbols

1 Ion source 2 Chamber 3 Chamber leak solenoid valve 4 Vacuum pump main pump 5 Chamber exhaust solenoid valve 6 Rotary pump vent valve 7 Rotary pump 8 Flow rate regulator 10 Vacuum exhaust controller

Claims (4)

In an ion generator of an ion beam processing apparatus,
An ion generator characterized in that an operation of injecting a gas into an ion source is performed a plurality of times in a short time in a flash form.   2. The ion generating apparatus according to claim 1, wherein the operation of injecting the gas into the ion source in a flash shape is performed by turning on / off a gas electromagnetic valve for sending the gas to the ion source.   The ion generator according to claim 1 or 2, wherein the cycle of the on / off operation is to perform an electromagnetic valve opening / closing operation of about 1 second 2 to 3 times.   4. The ion generator according to claim 1, wherein the gas is any one of argon gas, helium gas, and nitrogen gas.

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