JPH01305391A - Neutral particle injecting apparatus - Google Patents

Abstract

PURPOSE:To improve accuracy in measurement of beam quantity by operating the quantity of a neutral particle beam based on the beam current and the vacuum degree which are measured with a beam-current measuring device and a vacuum gage and a neutralizing coefficient of an ion beam in a neutralizing chamber which is stored beforehand. CONSTITUTION:A beam current I<+> of an ion beam 4c which is deflected with a deflector 14 is measured with a beam-current measuring device 20. A vacuum degree P in a neutralizing chamber 8 is measured with a vacuum gage 22. The measured values are sent into an operating device 24. An alpha lead-out part 26 is provided in the device 24. Several kinds of vacuum degree vs. ion beam curves which are obtained beforehand are stored. The coefficient alpha at any time is led out. An In operating part 28 is provided in the device 24. Operation is performed by using a specified expression based on the coefficient alpha from the lead-out part 26 and the vacuum degree P from the measuring device 20. Thus, the quantity In of a neutral beam 16 which is inputted into a target 18 is operated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The second invention relates to a neutral particle injection device that injects neutral particles by making a neutral particle beam incident on a target, and particularly relates to a neutral particle injection device that injects neutral particles by injecting a neutral particle beam into a target. Concerning means for determining quantities.

[Conventional technology]

FIG. 3 is a schematic diagram showing an example of a conventional neutral particle injection device.

This device consists of an ion beam 4 extracted from an ion source 2.
A is mass-analyzed by an analysis electromagnet 6 to selectively derive an ion beam 4b consisting of ions of a desired mass, which is led to a neutralization chamber 8 and neutralized there.

That is, a gas 12 such as argon is introduced into the neutralization chamber 8 through a flow rate regulator 11, and when the ion beam 4b collides with the molecules of this gas, charge conversion is performed and a portion of the gas is neutralized. That is, a neutral particle beam 16 is created. Note that the upstream and downstream sides of this neutralization chamber 8 are partitioned by slits 9 and 10 that reduce conductance so as not to impair the degree of vacuum around the chamber.

A deflector 14 such as a deflection electrode or a deflection magnet is provided on the downstream side of the neutralization chamber 8 to deflect the ion beam 4c that has not been neutralized and separate it from the neutral particle beam 16. The neutral particle beam 16 that has passed through the vessel 16 is made incident on the target and injected into it. 19 in the figure is a vacuum container.

[Problem to be solved by the invention]

However, in such a neutral particle injection device, there has been no specific means for accurately measuring the amount of neutral particles injected into the target 18.

Therefore, the reproducibility of the injection amount was also poor.

This is because, in the case of ion implantation, the ion beam current flowing through the target can be measured and the implantation amount can be calculated accurately based on that, whereas the neutral particle beam 16 is injected into the target 18. This is because no current flows there, so the beam amount of the neutral particle beam 16 that is incident on the target 18 cannot be measured as a current.

If the amount of the neutral particle beam 16 that is incident on the target 18 is known, the amount of neutral particles to be implanted into the target 18 can be accurately calculated in the same manner as in the case of ion implantation.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a neutral particle injection device that can determine the amount of a neutral particle beam incident on a target.

[Means to solve the problem]

The neutral particle implantation device of the present invention includes a beam current measuring device that measures the beam current of the ion beam deflected by the deflector, a vacuum gauge that measures the degree of vacuum in the neutralization chamber, and a vacuum gauge that measures the degree of vacuum in the neutralization chamber. an arithmetic device that calculates the amount of the neutral particle beam guided to the target based on the beam current and degree of vacuum and a pre-stored coefficient related to neutralization of the ion beam in the neutralization chamber; It is characterized by

〔Example〕

FIG. 1 is a schematic diagram showing a neutral particle injection device according to an embodiment of the present invention. The same reference numerals are given to the same or corresponding parts as in the example of FIG. 3, and the differences from the conventional example will be mainly explained below.

The ion beam remaining without being neutralized in the neutralization chamber 8 as described above, that is, the ion beam 4c deflected by the deflector 14
The beam current ■゛ is 1" = ToexpC-αP)
). Here, Io is the current of the ion beam 4b before entering the neutralization chamber 8, P is the degree of vacuum in the neutralization chamber 8, and α is a coefficient related to neutralization of the ion beam 4b at 8° in the neutralization chamber. It represents the charge conversion cross-sectional area, etc. in the device.

Therefore, the target 1 leaves the neutralization chamber 8 and enters the injection chamber 30.
The beam amount In of the neutral particle beam 16 guided by
).

Therefore, in this embodiment, a beam current measuring device 20 such as a Faraday system is provided in the branch part 32 of the vacuum vessel 19.
The beam current I' of the ion beam 4c deflected by the deflector 14 is measured, and a vacuum gauge 22 is attached to the neutralization chamber 8 to measure the degree of vacuum P in the neutralization chamber 8, and these values are is taken into the arithmetic unit 24.

On the other hand, the coefficient α is unique to the device and changes depending on the degree of vacuum P of the neutralization chamber 8 and the type and energy of the ion beam 4b.

However, if only the necessary types of curves as shown in Fig. 2 representing the above equation (1) are obtained in advance through experiments, then the degree of vacuum P and the type and energy of the ion beam 4b can be adjusted based on it. Therefore, in this embodiment, an α derivation unit 26 is provided in the arithmetic unit 24, and several types of curves such as those described above are stored therein, and the coefficient α can be obtained from the vacuum gauge 22. The coefficient α at each time is derived based on the degree of vacuum P set there or the type and energy of the ion beam 4b given from a higher-level control device.

Furthermore, an In calculation section 28 is provided in the calculation device 24,
Coefficient α given from the α derivation section 26, beam current ■3 given from the beam current measuring device 20, and vacuum gauge 2
The beam amount In of the neutral particle beam 16 that is incident on the target 18 is calculated by calculating the above equation (2) based on the degree of vacuum P given by 2.

Incidentally, such arithmetic device 24 can be easily configured using, for example, a microcomputer.

Therefore, according to the above configuration, the beam amount In of the neutral particle beam 16 incident on the target 18 can be determined automatically, continuously, and accurately. As a result, it becomes possible to accurately calculate the amount of neutral particles to be injected into the target 18, which in turn leads to improved reproducibility of the amount to be injected.

〔Effect of the invention〕

As described above, according to the present invention, the beam amount of the neutral particle beam incident on the target can be accurately determined.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a neutral particle injection device according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of the relationship between the degree of vacuum in the neutralization chamber and the amount of ion beam remaining without being neutralized therein. FIG. 3 is a schematic diagram showing an example of a conventional neutral particle injection device. 4a-4C...Ion beam, 8...Neutralization chamber, 1
4... Deflector, 16... Neutral particle beam, 18...
・Target, 20... Beam current measuring device, 22...
・Vacuum gauge, 24...Arithmetic device.

Claims (1)

[Claims] (1) Equipped with a neutralization chamber that neutralizes the ion beam, and a deflector located downstream of the neutralization chamber that deflects the ion beam that has not been neutralized and separates it from the neutral particle beam. In a neutral particle implanter configured to make a neutral particle beam that has passed through a neutral particle beam enter a target, a beam current measuring device that measures the beam current of the ion beam deflected by the deflector, and a vacuum in the neutralization chamber are provided. neutral particles guided to the target based on the beam current and vacuum degree measured by the vacuum gauge and a pre-stored coefficient related to neutralization of the ion beam in the neutralization chamber; A neutral particle injection device comprising: a calculation device for calculating a beam amount of a beam.