KR100933010B1 - An apparatus for controlling dose-rate of ion/electron beam using pulse interval modulation and the control method - Google Patents

Abstract

PURPOSE: An apparatus for controlling the amount of ion/electron beam using a pulse interval modulation and a control method are provided to radiate beam of a charge particle on an object sample by modulating a pulse beam according a period of a sinusoidal wave of the alternating-current electromagnet. CONSTITUTION: In a device, a beam generator(100) generates a pulse beam of a charged particle. An alternating-current electromagnet(200) is comprised of a pair of magnetic poles which is faced with each other and generates alternating current bipolar magnetic field. A power supply unit(300) supplies power to the alternating-current electromagnet. A timing signal generation unit(400) generates a timing signal and provides a beam generator. A current flowing in the alternating-current electromagnet is formed with a form of a sinusoidal wave. The beam generator is formed with an ion source or an electron gun.

Description

An apparatus for controlling dose-rate of ion / electron beam using pulse interval modulation and the control method

The present invention relates to a beam irradiation amount control device and a control method using a pulse repetition rate modulation, and more particularly, in the irradiation of charged particle beams such as ions or electrons to the target sample by using an alternating electromagnet, pulse beam generated per unit time The present invention relates to a beam irradiation amount control apparatus and method using pulse repetition rate modulation, in which a beam irradiated to a target sample is uniformly irradiated at all positions by modulating and irradiating the number of sine waves according to a sinusoidal current cycle of an alternating current electromagnet.

In general, an ion beam or an ion beam obtained from an ion source, an electron gun, or a particle accelerator is a flow of ions or electrons having positive or negative charges, and the production of radioisotopes including analysis of material structures such as atoms and molecules. It is widely used in the processing of integrated circuits and the like.

In irradiating a beam of charged particles such as ions or electrons to a target sample, the irradiated ion beam or electron beam is usually several mm in diameter. After being spread out, the sample is irradiated.

As described above, the AC dipole electric field or the AC dipole magnetic field used to straighten the beam of charged particles is divided by the following equation.

Force by magnetic field F = q (charge) x V (particle velocity) x B (magnetic field strength)

Force by electric field F = q (charge) x E (strength of electric field)

As shown in the above equation, the force exerted on the charged particles is proportional to the particle velocity, i.e., the energy level and the intensity of the magnetic field, in the case of the alternating dipolar magnetic field, and is proportional to the intensity of the electric field in the alternating bipolar electric field.

Accordingly, when the velocity of the particle is close to zero, the force applied to the charged particles is insignificant in the case of the alternating dipolar magnetic field even though the strength of the magnetic field is increased. Depending on the strength, sufficient force can be applied to the charged particles.

On the other hand, if the velocity of the particles is very high, the alternating bipolar magnetic field can apply sufficient force to the charged particles in proportion to the rapid velocity of the particles even when the strength of the magnetic field is weakly applied, making it easier to control the direction of the irradiated beam. Do.

Therefore, in controlling the irradiation direction of the charged particle beam, the alternating current bipolar electric field is usually advantageous at low energy specifications of several tens of keV or less, and the alternating current bipolar magnetic field is advantageous at high energy specifications.

As described above, in the case of alternating electric fields, it is advantageous in the case of low energy of several tens of keV or less, but in the case of particles having high energy or light such as electrons, a high voltage is not generally used.

On the other hand, the AC dipolar magnetic field can be used even in the case of high energy or electron, but due to the inductance inherent in the electromagnet, it is difficult to supply a current in the form of a sawtooth wave and is generally operated by a sinusoidal current.

However, when irradiating a target sample by adjusting the irradiation direction of the charged particle beam through an alternating electromagnet operated by a sine wave, the charged particle beam generally shows a constant pulse repetition rate, that is, the number of pulse beams generated per unit time is always constant. Therefore, there is a problem that the irradiation amount of the beam irradiated to the target sample appears unevenly due to the influence of the sine wave current added to the alternating electromagnet.

In other words, as shown in FIG. 1, when the beam having a constant pulse repetition rate generated from the beam generator 10 is irradiated to the target sample via the alternating current electromagnet 20 operated with a sinusoidal current, the beam irradiation direction Is adjusted according to the sine wave current of the alternating current electromagnet 20, and thus high irradiation dose is obtained at both side ends of the irradiation window 30 compared to the center portion.

Therefore, in order to irradiate the charged sample beam to the target sample with a uniform dose using the conventional beam irradiation apparatus as described above, only the beam in the center portion of the irradiation window 30 should be irradiated to the target sample. Since the beams at both end portions of 30) become unnecessary, the beams cannot be used efficiently.

In addition, in order to irradiate a beam of uniform irradiation amount to the target sample, the charged particle beam must be repeatedly moved while moving according to the position of the target sample, so that the overall irradiation uniformity is not good and economical by repeated beam irradiation. There is also a problem that causes a loss.

The present invention is to solve the above problems according to the prior art. That is, an object of the present invention by irradiating a beam of charged particles such as ions or electrons to the target sample by using an alternating current electromagnet, by modulating the number of pulse beams generated per unit time in accordance with the sine wave type current period of the alternating current electromagnet By irradiating, the beam irradiated to a target sample is irradiated uniformly at all positions.

The present invention as a technical idea for achieving the above object is an alternating current that is composed of a beam generating unit for generating a pulse beam of charged particles, a pair of magnetic poles opposed to each other in the horizontal direction is excited by a sinusoidal current to form an alternating current bipolar magnetic field A timing signal is generated to provide a timing signal to modulate the number of pulse beams generated per unit time in an electromagnet, a power supply unit supplying power to the AC electromagnet, and the beam generator in accordance with a sinusoidal current period of the AC electromagnet. It is configured to include a signal generator.

In the beam irradiation dose control apparatus and method using pulse repetition rate modulation according to the present invention, in irradiating a beam of charged particles such as ions or electrons to a target sample by using an alternating current electromagnet, the number of pulse beams generated per unit time is determined by alternating electromagnets. By modulating and irradiating a sinusoidal current cycle in the form of a sinusoidal wave, the beam of charged particles can be uniformly irradiated onto the target sample.

In addition, it is also possible to use all the beams of the irradiation area to prevent unnecessary loss of the beam, thereby improving the utilization rate of the beam irradiation apparatus to obtain an economic benefit.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating an apparatus for adjusting a beam dosage using pulse repetition rate modulation according to an embodiment of the present invention.

As shown in Figure 2, the beam irradiation amount control apparatus using pulse repetition rate modulation according to an embodiment of the present invention is a beam generator 100 for generating a charged particle beam, a pair of magnetic poles facing each other in the horizontal direction AC electromagnet 200, which is excited by a sinusoidal current to form an AC bipolar magnetic field, a power supply unit 300 for supplying power to the AC electromagnet 200, and generated per unit time of a beam generated by the beam generator 100 The timing signal generator 400 generates a timing signal and modulates the number of pulses according to the sine wave current period of the AC electromagnet 200.

The beam generator 100 is composed of an ion source, an electron gun, an accelerator, or the like to generate beams of charged particles such as ions or electrons, that is, ion beams, electron beams, and the like.

AC electromagnet 200 is composed of a pair of magnetic poles which are positioned to face each other in the horizontal direction, the pair of magnetic poles is composed of a plane in which the opposing surfaces are parallel to each other, the gap is kept constant.

The AC electromagnet 200 is excited and operated with a sinusoidal current, and the AC electromagnet 200 has a particle velocity of the beam such that the beam generated from the beam generator 100 can be irradiated to a target sample having a large area. That is, an alternating dipolar magnetic field is formed to adjust the irradiation direction of the beam in proportion to the energy level.

Accordingly, the beam is generated from the beam generating unit 100 is the irradiation direction is controlled through the AC two-pole magnetic field formed in the AC electromagnet 200.

The power supply unit 300 supplies power to the AC electromagnet 200 to supply an electric current such that an AC bipolar magnetic field is formed.

The timing signal generator 400 is connected to the beam generator 100 so that the pulse repetition rate of the beam generated by the beam generator 100, ie, the number of pulse beams generated per unit time, is formed in the sine wave form of the AC electromagnet 200. Generates a timing signal to be modulated according to a current period and inputs the timing signal to the beam generator 100.

Through such a configuration, as shown in FIG. 2, the particle beam having passed through the beam irradiation amount adjusting device according to the present invention may be irradiated constantly regardless of the position of both side end portions and the center portion of the object to be irradiated.

At this time, the pulse repetition rate of the charged particle beam according to the sine wave current period of the alternating current electromagnet 200 will be described in detail with reference to Figure 3 to adjust the dose.

3 is a view showing a method of modulating the repetition rate of the pulse 700 of the charged particle beam according to the period of the sinusoidal wave 600 of the AC electromagnet according to an embodiment of the present invention.

As shown in FIG. 3, the current flowing in the alternating electromagnet is in the form of a sine wave, that is, a sinusoidal wave 600.

In other words, the waveform in the vicinity of the maximum value and the minimum value has a convex shape as compared to the sawtooth waveform current suitable for uniformly adjusting the irradiation direction, and the irradiation direction is adjusted according to the waveform shape of the sinusoidal wave 600. The irradiation direction of the particle beam irradiated onto the sample is more biased toward the maximum and minimum value portions than the reference value portion of the sinusoidal wave 600 waveform, so that when the particle beam having the same pulse repetition rate is irradiated, both side ends are centered in the beam irradiation region. More radiation is obtained.

Accordingly, the apparatus for controlling the beam dosage using the pulse 700 repetition rate modulation according to the present invention is to adjust the pulse 700 repetition rate of the beam, that is, the number of pulses 700 beams generated per unit time to the period of the sine wave 600 of the AC electromagnet. By modulating accordingly, the beam is irradiated to the target sample with a uniform dose.

That is, in the maximum and minimum value portions of the sinusoidal wave 600 waveform, the interval between the pulse 700 and the pulse 700 is widened to reduce the number of pulse 700 beams generated per unit time, and the pulse 700 in the reference value portion of the waveform. By increasing the number of pulses (700) beams generated per unit time by narrowing the interval between the) to be uniformly controlled the irradiation amount of the beam irradiated to the target sample.

As such, the beam irradiation amount adjusting device and the adjusting method using pulse repetition rate modulation according to the present invention improve the uniformity of irradiation of the beam irradiated to the target sample by allowing the charged particle beam to be irradiated uniformly on the target sample regardless of the position. .

In addition, it is possible to use all the beams of the irradiation area to prevent unnecessary loss of the beam to improve the utilization rate of the beam irradiation apparatus to obtain an economic benefit.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be clear to those who have knowledge of God.

1 is a view showing a beam irradiation apparatus and a dose according to the prior art.

2 is a view showing an apparatus for adjusting the beam dosage using pulse repetition rate modulation according to an embodiment of the present invention.

3 is a diagram illustrating a method of modulating a pulse repetition rate of a charged particle beam according to a sinusoidal period of an alternating current electromagnet according to an embodiment of the present invention;

<Description of the symbols for the main parts of the drawings>

10, 100: beam generator 20, 200: AC electromagnet

30: irradiation window 300: power supply

400: timing signal generator 600: sine wave

700 pulse

Claims (3)

In the device for adjusting the irradiation direction of the particle beam irradiated to the target sample by using an alternating electromagnet, A beam generator for generating a pulse beam of charged particles; An alternating current electromagnet composed of a pair of magnetic poles opposed to each other in a horizontal direction and excited by a sine wave current to form an alternating current bipolar magnetic field; A power supply unit supplying power to the AC electromagnet; And A timing signal generator for generating a timing signal to modulate the number of pulse beams generated per unit time in the beam generator according to a sinusoidal current period of the AC electromagnet; Beam irradiation amount control apparatus using a pulse repetition rate modulation, characterized in that configured to include. In a method of irradiating a target sample with a particle beam generated using a beam generating unit for generating a pulse beam of charged particles and an alternating electromagnet excited with a sine wave current to form an alternating dipolar magnetic field, The particle beam irradiated to the target sample by modulating the number of pulse beams generated per unit time in the beam generator for generating the pulse beam of the charged particles through a timing signal modulated according to the waveform of the sinusoidal current exciting the AC electromagnet. Beam irradiation amount adjustment method using the pulse repetition rate modulation, characterized in that for adjusting the dose amount for each area of the. The method of claim 2, Modulation of the pulse beam through the timing signal, In the maximum and minimum values of the sine wave, the interval between pulses of the charged particle beam is widened to reduce the number of pulse beams generated per unit time, and in the reference value portion of the sine wave, the interval between pulses of the charged particle beam is narrowed per unit time. The method of controlling the beam irradiation amount using pulse repetition rate modulation, by increasing the number of pulse beams generated, thereby uniformly adjusting the amount of irradiation of the particle beam irradiated onto the target sample.

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