JP7476090B2 - Ion source and ion beam device - Google Patents

Description

The present invention relates to an ion source and an ion beam device.

An inductively coupled plasma ion source is known as an ion source. As disclosed in Patent Document 1, an inductively coupled plasma ion source can be used as an ion source for a focused ion beam device.

The inductively coupled plasma ion source includes, for example, a vacuum vessel, a plasma generation coil arranged outside the vacuum vessel, and a high-frequency power supply. When a high-frequency voltage generated by the high-frequency power supply is applied to the plasma generation coil, plasma is generated in the plasma generation space inside the vacuum vessel. The plasma contains ions that are the ionized gas inside the vacuum vessel. The ions extracted from the plasma generation space by the extraction voltage are accelerated by the acceleration voltage and released from the ion source.

JP 2015-122325 A

An acceleration voltage is applied to the plasma generation space to accelerate the ions. Therefore, a high voltage is applied between the plasma generation space and the plasma generation coil. For example, when the acceleration voltage is 30 kV, a voltage of 30 kV is applied between the plasma generation space and the plasma generation coil. Therefore, in such an ion source, insulation is maintained by, for example, sandwiching an insulator with a thickness of several mm to several tens of mm between the plasma generation coil and the plasma generation space.

However, if an insulator is placed between the plasma generation space and the plasma generation coil, the distance between the plasma generation space and the plasma generation coil increases, weakening the magnetic coupling.

One aspect of the ion source according to the present invention is
a vacuum vessel into which a gas is introduced;
a plasma generating coil disposed outside the vacuum vessel and configured to generate plasma in a plasma generating space within the vacuum vessel;
a high frequency power source for supplying a high frequency voltage to the plasma generating coil via a coupling circuit;
an acceleration electrode for accelerating ions generated in the plasma generation space;
an accelerating voltage power supply for supplying an accelerating voltage to the accelerating electrode;
A matching circuit;
Including,
The acceleration voltage is supplied to the plasma generation coil via an impedance element ,
The high frequency power supply supplies a high frequency voltage to the plasma generation coil via the matching circuit,
The matching circuit includes:
A first variable capacitor connected in parallel with the plasma generating coil;
A second variable capacitor connected in series with the plasma generating coil;
a first resistor connected in parallel with the second variable capacitor;
including.
One aspect of the ion source according to the present invention is
a vacuum vessel into which a gas is introduced;
a plasma generating coil disposed outside the vacuum vessel and configured to generate plasma in a plasma generating space within the vacuum vessel;
a high frequency power source for supplying a high frequency voltage to the plasma generating coil via a coupling circuit;
an acceleration electrode for accelerating ions generated in the plasma generation space;
an accelerating voltage power supply for supplying an accelerating voltage to the accelerating electrode;
a voltage dividing circuit for supplying a voltage obtained by dividing the acceleration voltage to the plasma generating coil;
Including,
The acceleration voltage is supplied to the plasma generation coil via an impedance element.
One aspect of the ion source according to the present invention is
a vacuum vessel into which a gas is introduced;
a plasma generating coil disposed outside the vacuum vessel and configured to generate plasma in a plasma generating space within the vacuum vessel;
a high frequency power supply for supplying a high frequency voltage to the plasma generating coil via a coupling circuit;
an acceleration electrode for accelerating ions generated in the plasma generation space;
an accelerating voltage power supply for supplying an accelerating voltage to the accelerating electrode;
a Faraday shield disposed between the plasma generating coil and the vacuum vessel;
The acceleration voltage is supplied to the plasma generation coil via an impedance element,
The accelerating voltage is supplied to the Faraday shield.

In such an ion source, since an acceleration voltage is supplied to the plasma generating coil via an impedance element, the difference between the potential of the plasma generating space and the potential of the plasma generating coil can be reduced. This allows the distance between the plasma generating space and the plasma generating coil to be reduced. Therefore, in such an ion source, the magnetic coupling between the plasma generating space and the plasma generating coil can be strengthened.

One aspect of the ion beam apparatus according to the present invention is to
The ion source includes the above.

FIG. 2 is a diagram showing the configuration of an ion source according to the first embodiment. FIG. 13 is a diagram showing the configuration of an ion source according to a second embodiment. FIG. 13 is a diagram showing the configuration of an ion source according to a third embodiment. FIG. 13 is a diagram showing the configuration of an ion source according to a fourth embodiment. FIG. 13 is a diagram showing the configuration of an ion source according to a fifth embodiment. FIG. 13 is a diagram showing the configuration of an ion beam apparatus according to a sixth embodiment.

Below, preferred embodiments of the present invention are described in detail with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention described in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

1. First embodiment 1.1. Configuration of ion source First, an ion source according to the first embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing the configuration of an ion source 100 according to the first embodiment.

The ion source 100 is an inductively coupled plasma ion source. As shown in FIG. 1, the ion source 100 includes a vacuum vessel 2, a plasma generating coil 4, a Faraday shield 6, a radio frequency (RF) power supply 10, a matching circuit 20, a coupling circuit 30, an anode 40, an extraction electrode 42, a lens electrode 44, a cathode 46, an acceleration voltage power supply 50, an extraction voltage power supply 52, a lens voltage power supply 54, and a resistor 60.

The vacuum vessel 2 has a plasma generation space 3. A vacuum is maintained inside the vacuum vessel 2. Gas is introduced into the vacuum vessel 2 through a gas supply port (not shown). Plasma is generated in the plasma generation space 3 by applying a radio frequency (RF) voltage to the plasma generation coil 4.

The plasma generation coil 4 is disposed outside the vacuum vessel 2. The plasma generation coil 4 is wound around the vacuum vessel 2. In other words, the vacuum vessel 2 is disposed inside the plasma generation coil 4. The plasma generation coil 4 generates a high-frequency magnetic field in the plasma generation space 3 inside the vacuum vessel 2.

The Faraday shield 6 is disposed between the vacuum vessel 2 and the plasma generating coil 4. When the plasma generating coil 4 generates a high-frequency magnetic field, electrostatic vibrations occur along with the high-frequency magnetic field. These electrostatic vibrations affect the plasma generated in the plasma generating space 3. Therefore, in the ion source 100, the Faraday shield 6 reduces these electrostatic vibrations and reduces the effect of the electrostatic vibrations on the plasma. The high-frequency magnetic field generated by the plasma generating coil 4 passes through the Faraday shield 6. An acceleration voltage Vacc is supplied to the Faraday shield 6.

The high frequency power supply 10 supplies a high frequency voltage to the plasma generating coil 4.
As shown in FIG. 1, the RF power supply 10 supplies a high frequency voltage to the plasma generating coil 4 via a matching circuit 20 and a coupling circuit 30 .

The matching circuit 20 performs impedance matching between the high frequency power supply 10 and the plasma generation coil 4. The matching circuit 20 includes a first variable capacitor 22, a second variable capacitor 24, and a resistor 26. The first variable capacitor 22 is connected in parallel with the plasma generation coil 4. The second variable capacitor 24 is connected in series with the plasma generation coil 4. The first variable capacitor 22 and the second variable capacitor 24 are adjusted so that the reflected wave of the high frequency power is reduced.

The resistor 26 is connected in parallel with the second variable capacitor 24. The resistance value of the resistor 26 is large enough so as not to affect the transmission of high-frequency power.

The coupling circuit 30 blocks the DC component of the high frequency voltage and passes the AC component. The coupling circuit 30 includes a first coupling capacitor 32 and a second coupling capacitor 34. The first coupling capacitor 32 is connected to the first coil end C1 of the plasma generating coil 4, and the second coupling capacitor 34 is connected to the second coil end C2 of the plasma generating coil 4. The first coupling capacitor 32 is provided in a path connecting the high frequency power supply 10 and the first coil end C1. The second coupling capacitor 34 is provided in a path connecting the high frequency power supply 10 and the second coil end C2. The second coupling capacitor 34 and the second variable capacitor 24 are connected in series.

The anode 40 is an acceleration electrode for accelerating ions generated in the plasma generation space 3. An acceleration voltage Vacc is applied to the anode 40. The anode 40 applies the acceleration voltage Vacc to the plasma generation space 3.

The extraction electrode 42 is an electrode for extracting ions generated in the plasma generation space 3. An extraction voltage Vex is applied to the extraction electrode 42.

The lens electrode 44 generates an electric field for focusing the ion beam extracted by the extraction electrode 42. A lens voltage V _Lens is applied to the lens electrode 44.

The cathode 46 is an electrode for accelerating ions generated in the plasma generation space 3. An acceleration voltage Vacc is applied between the anode 40 and the cathode 46. The cathode 46 is connected to, for example, ground G.

The acceleration voltage power supply 50 generates an acceleration voltage Vacc. The acceleration voltage power supply 50 supplies the acceleration voltage Vacc to the anode 40. The extraction voltage power supply 52 supplies an extraction voltage Vex to the extraction electrode 42. The extraction voltage Vex is a voltage biased by the extraction voltage power supply 52 with the acceleration voltage Vacc as a reference voltage. The lens voltage power supply 54 supplies a lens voltage V _Lens to the lens electrode 44.

The resistor 60 is connected to the second coil end C2. The resistor 60 is electrically connected between the second coil end C2 and the output of the acceleration voltage power supply 50. The resistor 60 may also be connected to the first coil end C1.

The resistor 60 functions as an impedance element that has a high impedance at high frequencies. The resistor 60 limits the current that flows into the plasma generating coil 4 due to the acceleration voltage Vacc. A choke coil or the like may also be used as the impedance element. The acceleration voltage Vacc is supplied to the plasma generating coil 4 via the resistor 60.

1.2 Operation Next, a description will be given of the operation of the ion source 100. The following describes the case where the acceleration voltage Vacc is 30 kV.

The high-frequency voltage generated by the high-frequency power supply 10 is applied to one pole of the first coupling capacitor 32 and one pole of the second coupling capacitor 34 via a matching circuit 20 including a first variable capacitor 22 and a second variable capacitor 24.

Here, the other pole of the first coupling capacitor 32 is connected to the first coil end C1, and the other pole of the second coupling capacitor 34 is connected to the second coil end C2. In addition, an acceleration voltage Vacc is applied to the plasma generation coil 4 via a resistor 60. Therefore, the potential of the plasma generation coil 4 is close to that of the plasma generation space 3, that is, a potential of about 30 kV. Therefore, a DC voltage of 30 kV is applied between the output terminal of the high frequency power supply 10 and the plasma generation coil 4.

In the ion source 100, the second variable capacitor 24 and the second coupling capacitor 34 are connected in series. For example, if the resistor 26 does not exist, the DC voltage of 30 kV is divided by the second variable capacitor 24 and the second coupling capacitor 34. Therefore, a high voltage is applied to the second variable capacitor 24.

The ion source 100 includes a resistor 26 connected in parallel with the second variable capacitor 24. Therefore, the DC component applied to the second variable capacitor 24 is 0 V, and the high frequency component passes through the second variable capacitor 24. Therefore, the DC component of 30 kV is applied only to the second coupling capacitor 34, and the DC component applied to the second variable capacitor 24 is 0 V. In this way, the ion source 100 can prevent a high voltage from being applied to the second variable capacitor 24 by using the resistor 26. The resistance value of the resistor 26 is set to a value large enough not to affect the transmission of high frequency power. The resistor 26 is set to, for example, 10 MΩ.

As described above, the acceleration voltage Vacc is applied to the plasma generation coil 4 via the resistor 60. Therefore, a DC voltage of 30 kV is applied to the first coupling capacitor 32 and the second coupling capacitor 34. Therefore, the difference between the potential of the plasma generation space 3 and the potential of the plasma generation coil 4 is approximately 0 V. In other words, no high voltage is applied between the plasma generation space 3 and the plasma generation coil 4. As a result, there is no need to sandwich an insulator with a thickness of several mm to several tens of mm between the vacuum vessel 2 and the plasma generation coil 4, and the distance between the plasma generation space 3 and the plasma generation coil 4 can be reduced.

Similarly, an acceleration voltage Vacc is applied to the Faraday shield 6. Therefore, the difference between the potential of the plasma generation space 3 and the potential of the Faraday shield 6 is approximately 0 V. Also, the difference between the potential of the Faraday shield 6 and the potential of the plasma generation coil 4 is approximately 0 V. Therefore, the distance between the plasma generation space 3 and the Faraday shield 6, and the distance between the Faraday shield 6 and the plasma generation coil 4 can be reduced.

A high frequency voltage generated by the high frequency power supply 10 is applied to the plasma generation coil 4, and plasma is continuously generated in the plasma generation space 3 in the vacuum vessel 2. Gas introduced into the vacuum vessel 2 from a gas inlet (not shown) is ionized by the plasma. The generated ions are extracted by an extraction voltage Vex, and the extracted ions are accelerated by an acceleration voltage Vacc. The ion beam generated in this manner is focused by a lens (electrostatic field) created by the lens electrode 44 to which a lens voltage V _Lens is applied, and is emitted from the ion source 100.

1.3. Effects and Effects The ion source 100 includes a vacuum vessel 2 into which a gas is introduced, a plasma generation coil 4 that is disposed outside the vacuum vessel 2 and generates plasma in a plasma generation space 3 in the vacuum vessel 2, a high frequency power supply 10 that supplies a high frequency voltage to the plasma generation coil 4 via a coupling circuit 30, an anode 40 as an accelerating electrode for accelerating ions generated in the plasma generation space 3, and an acceleration voltage power supply 50 that supplies an acceleration voltage Vacc to the anode 40. The acceleration voltage Vacc is also supplied to the plasma generation coil 4 via a resistor 60.

In this way, in the ion source 100, the acceleration voltage Vacc is supplied to the plasma generating coil 4 via the resistor 60, so that the difference between the potential of the plasma generating space 3 and the potential of the plasma generating coil 4 can be reduced, and the distance between the plasma generating space 3 and the plasma generating coil 4 can be reduced. Therefore, the magnetic coupling between the plasma generating space 3 and the plasma generating coil 4 can be strengthened, and the energy transfer efficiency can be improved. As a result, the high frequency power supply 10 can be made smaller. In addition, in the ion source 100, the energy transfer efficiency can be improved, so that the leakage magnetic flux to areas other than the plasma generating space 3 can be reduced, and the heat generation of the device can be reduced.

In the ion source 100, the high-frequency power supply 10 supplies a high-frequency voltage to the plasma generation coil 4 via a matching circuit 20. The matching circuit 20 also includes a first variable capacitor 22 connected in parallel to the plasma generation coil 4, a second variable capacitor 24 connected in series to the plasma generation coil 4, and a resistor 26 connected in parallel to the second variable capacitor 24. In this way, in the ion source 100, since the resistor 26 is connected in parallel to the second variable capacitor 24, it is possible to prevent a high voltage from being applied to the second variable capacitor 24.

In the ion source 100, the Faraday shield 6 is disposed between the vacuum vessel 2 and the plasma generating coil 4, and an acceleration voltage Vacc is supplied to the Faraday shield 6. Therefore, in the ion source 100, the difference between the potential of the plasma generating space 3 and the potential of the Faraday shield 6 can be reduced, and the difference between the potential of the Faraday shield 6 and the potential of the plasma generating coil 4 can be reduced. Therefore, the distance between the plasma generating space 3 and the Faraday shield 6, and the distance between the Faraday shield 6 and the plasma generating coil 4 can be reduced. That is, in the ion source 100, the distance between the plasma generating space 3 and the plasma generating coil 4 can be reduced.

1, the matching circuit 20 includes the first variable capacitor 22, the second variable capacitor 24, and the resistor 26, but the configuration of the matching circuit 20 is not limited to this. Depending on the conditions of the high frequency power supply 10 and the plasma generating coil 4, the ion source 100 may not include the matching circuit 20.

2. Second embodiment 2.1. Configuration of ion source Next, an ion source according to a second embodiment will be described with reference to the drawings. Fig. 2 is a diagram showing the configuration of an ion source 200 according to the second embodiment. Hereinafter, in the ion source 200 according to the second embodiment, components having the same functions as those of the ion source 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the ion source 100 shown in Fig. 1 described above, the acceleration voltage Vacc is applied to the plasma generation coil 4 via the resistor 60. In contrast to this, the ion source 200 shown in Fig. 2 includes a voltage dividing circuit 210, and a voltage obtained by dividing the acceleration voltage Vacc by the voltage dividing circuit 210 is applied to the plasma generation coil 4. In this way, in the ion source 200, the potential of the plasma generation coil 4 can be set to a desired potential between the acceleration voltage Vacc and the ground G by the voltage dividing circuit 210.

Here, supplying the acceleration voltage Vacc to the plasma generating coil 4 includes a case where the acceleration voltage Vacc is applied directly to the plasma generating coil 4 as shown in FIG. 1, and a case where the acceleration voltage Vacc is applied to the plasma generating coil 4 via a voltage divider circuit 210 or the like as shown in FIG. 2.

The voltage divider circuit 210 includes a resistor 60 and a resistor 212. The resistor 212 is electrically connected between the second coil end C2 of the plasma generation coil 4 and the ground G.

The ion source 200 further includes a voltage divider circuit 220. A voltage obtained by dividing the acceleration voltage Vacc by the voltage divider circuit 220 is supplied to the Faraday shield 6.

The voltage divider circuit 220 includes a resistor 222 and a resistor 224. The resistor 222 is electrically connected between the Faraday shield 6 and the output of the acceleration voltage power supply 50. The resistor 224 is electrically connected between the Faraday shield 6 and ground G.

2.2 Operation Next, a description will be given of the operation of the ion source 200. Below, the operation of the ion source 200 will be described with respect to points that are different from the operation of the ion source 100, and a description of similar points will be omitted.

For example, resistor 60 is 200 MΩ, resistor 212 is 100 MΩ, resistor 222 is 100 MΩ, resistor 224 is 200 MΩ, and acceleration voltage Vacc is 30 kV. In this case, the acceleration voltage Vacc of 30 kV is divided by voltage divider circuit 210, and a voltage of 10 kV is applied to plasma generation coil 4. In addition, the acceleration voltage Vacc of 30 kV is divided by voltage divider circuit 220, and a voltage of 20 kV is applied to Faraday shield 6.

That is, the potential of the plasma generation space 3 is 30 kV, the potential of the Faraday shield 6 is 20 kV, and the potential of the plasma generation coil 4 is 10 kV. Therefore, the voltage applied to the first coupling capacitor 32 and the voltage applied to the second coupling capacitor 34 is 10 kV.

2.3. Effects The ion source 200 includes a voltage dividing circuit 210 that supplies a voltage obtained by dividing the acceleration voltage Vacc to the plasma generating coil 4. Therefore, in the ion source 200, the potential of the plasma generating coil 4 can be set to a desired potential between the acceleration voltage Vacc and the ground G. Therefore, in the ion source 200, the voltage applied to the first coupling capacitor 32 and the voltage applied to the second coupling capacitor 34 can be reduced. This allows the withstand voltage of the first coupling capacitor 32 and the second coupling capacitor 34 to be lowered, and components with low withstand voltage can be used as the first coupling capacitor 32 and the second coupling capacitor 34. Furthermore, in the ion source 200, the insulation voltage of the wiring can be changed, thereby increasing the degree of freedom in design.

The ion source 200 includes a voltage dividing circuit 220 that supplies a voltage obtained by dividing the acceleration voltage Vacc to the Faraday shield 6. Therefore, in the ion source 200, the potential of the Faraday shield 6 can be set to a desired potential between the acceleration voltage Vacc and the ground G. Therefore, in the ion source 200, the potential of the plasma generation coil 4 can be made lower than the potential of the Faraday shield 6, and the potential of the Faraday shield 6 can be made lower than the potential of the plasma generation space 3.

3. Third embodiment 3.1. Configuration of ion source Next, an ion source according to a third embodiment will be described with reference to the drawings. Fig. 3 is a diagram showing the configuration of an ion source 300 according to the third embodiment. Hereinafter, in the ion source 300 according to the third embodiment, components having the same functions as those of the ion source 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the ion source 100 shown in FIG. 1 described above, the matching circuit 20 had a second variable capacitor 24 connected to one end of the second coupling capacitor 34.

In contrast, in the ion source 300, as shown in FIG. 3, the matching circuit 20 includes, in addition to the second variable capacitor 24, a third variable capacitor 324 connected to one end of the first coupling capacitor 32.

The matching circuit 20 includes a first variable capacitor 22, a second variable capacitor 24, a resistor 26, a third variable capacitor 324, and a resistor 326.

The third variable capacitor 324 is connected in series to the plasma generation coil 4. The first variable capacitor 22, the second variable capacitor 24, and the third variable capacitor 324 are adjusted so that the reflected waves of the high-frequency power are reduced.

Resistor 326 is connected in parallel with third variable capacitor 324. The resistance value of resistor 326 is large enough not to affect the transmission of high frequency power.

3.2 Operation Next, a description will be given of the operation of the ion source 300. Below, the operation of the ion source 300 will be described with respect to points that are different from the operation of the ion source 100, and a description of similar points will be omitted.

As described above, when the high-frequency voltage generated by the high-frequency power supply 10 is applied to the plasma generating coil 4 and the plasma generating coil 4 generates a high-frequency magnetic field, electrostatic vibration occurs along with the high-frequency magnetic field. The center of this electrostatic vibration can be adjusted by adding the third variable capacitor 324 to the matching circuit 20. For example, by adjusting the second variable capacitor 24 and the third variable capacitor 324, the electrostatic vibration at the first coil end C1 of the plasma generating coil 4 and the electrostatic vibration at the second coil end C2 of the plasma generating coil 4 can be offset. This reduces the effect of the electrostatic vibration on the plasma generated in the vacuum vessel 2. Therefore, the ion source 300 does not need to use the Faraday shield 6.

4. Fourth embodiment 4.1. Configuration of ion source Next, an ion source according to a fourth embodiment will be described with reference to the drawings. Fig. 4 is a diagram showing the configuration of an ion source 400 according to the fourth embodiment. Hereinafter, in the ion source 400 according to the fourth embodiment, members having the same functions as those of the ion source 100 according to the first embodiment, the ion source 200 according to the second embodiment, and the ion source 300 according to the third embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 4, the ion source 400 includes a voltage divider circuit 410 that supplies a divided voltage of the acceleration voltage Vacc to the plasma generation coil 4.

The voltage divider circuit 410 includes resistor 26, resistor 326, resistor 402, resistor 404, and resistor 60. Resistor 402 is connected in parallel with the first coupling capacitor 32. Resistor 404 is connected in parallel with the second coupling capacitor 34.

4.2 Operation Next, a description will be given of the operation of the ion source 400. Below, the operation of the ion source 400 will be described with respect to differences from the operations of the ion source 100, the ion source 200, and the ion source 300, and a description of similarities will be omitted.

For example, resistor 26 is 200 MΩ, resistor 326 is 200 MΩ, resistor 402 is 200 MΩ, resistor 404 is 200 MΩ, resistor 60 is 100 MΩ, and the acceleration voltage Vacc is 30 kV.

In this case, the 30 kV acceleration voltage Vacc is divided by the voltage divider circuit 410, and a voltage of 20 kV is applied to the plasma generation coil 4. A voltage of 10 kV is applied to the first coupling capacitor 32, and a voltage of 10 kV is applied to the second coupling capacitor 34. A voltage of 10 kV is applied to the second variable capacitor 24, and a voltage of 10 kV is applied to the third variable capacitor 324.

In this way, in the ion source 400, like the above-mentioned ion source 200, the voltage applied to the first coupling capacitor 32 and the voltage applied to the second coupling capacitor 34 can be reduced. Therefore, the ion source 400 can achieve the same effects as the ion source 200.

5. Fifth embodiment 5.1. Configuration of ion source Next, an ion source according to a fifth embodiment will be described with reference to the drawings. Fig. 5 is a diagram showing the configuration of an ion source 500 according to the fifth embodiment. Hereinafter, in the ion source 500 according to the fifth embodiment, components having the same functions as those of the ion source 400 according to the fourth embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The ion source 400 shown in FIG. 4 described above has one stage of a coupling capacitor and a resistor connected in parallel with the coupling capacitor, but the ion source 500 has two stages of such a set, as shown in FIG. 5.

5, in the ion source 500, the coupling circuit 30 includes a first coupling capacitor 32, a second coupling capacitor 34, a third coupling capacitor 532, and a fourth coupling capacitor 534. Also, in the ion source 500, the voltage divider circuit 410 includes a resistor 26, a resistor 326, a resistor 402, a resistor 404, a resistor 502, a resistor 504, and a resistor 60.

The third coupling capacitor 532 is connected in series with the first coupling capacitor 32. The fourth coupling capacitor 534 is connected in series with the second coupling capacitor 34. The third coupling capacitor 532 is connected to the first coil end C1 of the plasma generation coil 4. The fourth coupling capacitor 534 is connected to the second coil end C2 of the plasma generation coil 4.

The resistor 502 is connected in parallel with the third coupling capacitor 532.
4 is connected in parallel with the fourth coupling capacitor 534 .

5.2 Operation Next, a description will be given of the operation of the ion source 500. Below, the operation of the ion source 500 will be described with respect to points that are different from the operation of the ion source 400, and a description of similar points will be omitted.

For example, resistor 26 is 200 MΩ, resistor 326 is 200 MΩ, resistor 402 is 200 MΩ, resistor 404 is 200 MΩ, resistor 502 is 200 MΩ, resistor 504 is 200 MΩ, resistor 60 is 100 MΩ, and the acceleration voltage Vacc is 30 kV.

In this case, the 30 kV acceleration voltage Vacc is divided by the voltage divider circuit 410, and a voltage of 22.5 kV is applied to the plasma generation coil 4. A voltage of 7.5 kV is applied to the third coupling capacitor 532, and a voltage of 7.5 kV is applied to the fourth coupling capacitor 534. A voltage of 7.5 kV is applied to the first coupling capacitor 32, and a voltage of 7.5 kV is applied to the second coupling capacitor 34. A voltage of 7.5 kV is applied to the second variable capacitor 24, and a voltage of 7.5 kV is applied to the third variable capacitor 324.

As a result, a voltage of 7.5 kV is applied to the wiring 501 between the matching circuit 20 and the first coupling capacitor 32 and the second coupling capacitor 34. In this way, the ion source 500 can reduce the voltage applied to the wiring 501.

In the example shown in FIG. 5, a case is described in which two sets of coupling capacitors and resistors connected in parallel with the coupling capacitors are provided, but the number of sets is not particularly limited and may be three or more. Increasing the number of sets of coupling capacitors and resistors in this way makes it possible to further reduce the voltage applied to each element.

6. Sixth Embodiment Next, an ion beam apparatus according to a sixth embodiment will be described. Fig. 6 is a diagram showing the configuration of an ion beam apparatus 600 according to the sixth embodiment.

The ion beam device 600 is, for example, a focused ion beam device that uses a focused ion beam to process and observe a sample. The ion beam device 600 includes an ion source according to the present invention. Here, a case will be described in which the ion beam device 600 includes an ion source 100.

As shown in FIG. 6, the ion beam device 600 includes an ion source 100, a focusing lens 602, a blanking electrode 604, an objective lens aperture 606, an objective lens 608, a deflection plate 610, a detector 612, and a gas supply device 614.

The ion beam emitted from the ion source 100 is focused by the focusing lens 602 and the objective lens 608. In addition, the objective lens aperture 606 cuts off unnecessary ion beams. This forms a focused ion beam, which is then irradiated onto the sample S.

The ion beam can be blocked by deflecting it with the blanking electrode 604. In addition, the focused ion beam can be scanned over the sample S by two-dimensionally deflecting it with the deflection plate 610. This allows the sample S to be processed. Furthermore, a scanning ion image (SIM image) can be obtained by detecting secondary electrons generated by irradiating the sample S with the focused ion beam with a detector 612.

In addition, selective film formation can be performed by supplying a compound gas to the surface of the sample S using the gas supply device 614 and reacting the ion beam with the compound gas.

The above-described embodiments and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments. Substantially the same configurations are, for example, configurations that have the same functions, methods, and results, or configurations that have the same purpose and effect. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that have the same effects as the configurations described in the embodiments, or that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

2...vacuum vessel, 3...plasma generation space, 4...plasma generation coil, 6...Faraday shield, 10...high frequency power supply, 20...matching circuit, 22...first variable capacitor, 24...second variable capacitor, 26...resistance, 30...coupling circuit, 32...first coupling capacitor, 34...second coupling capacitor, 40...anode, 42...extraction electrode, 44...lens electrode, 46...cathode, 50...acceleration voltage power supply, 52...extraction voltage power supply, 54...lens voltage power supply, 60...resistance, 100...ion source, 200...ion source, 210...voltage division circuit, 212 ...resistor, 220...voltage divider circuit, 222...resistor, 224...resistor, 300...ion source, 324...third variable capacitor, 326...resistor, 400...ion source, 402...resistor, 404...resistor, 410...voltage divider circuit, 500...ion source, 501...wiring, 502...resistor, 504...resistor, 532...third coupling capacitor, 534...fourth coupling capacitor, 600...ion beam device, 602...focusing lens, 604...blanking electrode, 606...objective lens aperture, 608...objective lens, 610...deflection plate, 612...detector, 614...gas supply device

Claims (10)

a vacuum vessel into which a gas is introduced;
a plasma generating coil disposed outside the vacuum vessel and configured to generate plasma in a plasma generating space within the vacuum vessel;
a high frequency power source for supplying a high frequency voltage to the plasma generating coil via a coupling circuit;
an acceleration electrode for accelerating ions generated in the plasma generation space;
an accelerating voltage power supply for supplying an accelerating voltage to the accelerating electrode;
A matching circuit;
Including,
The acceleration voltage is supplied to the plasma generation coil via an impedance element ,
The high frequency power supply supplies a high frequency voltage to the plasma generation coil via the matching circuit,
The matching circuit includes:
A first variable capacitor connected in parallel with the plasma generating coil;
A second variable capacitor connected in series with the plasma generating coil;
a first resistor connected in parallel with the second variable capacitor;
an ion source comprising : In claim 1 ,
The coupling circuit includes:
a first coupling capacitor connected to a first coil end of the plasma generation coil;
a second coupling capacitor connected to a second coil end of the plasma generation coil;
Including,
The matching circuit includes:
a third variable capacitor connected in series with the plasma generating coil;
a second resistor connected in parallel with the third variable capacitor;
Including,
the second variable capacitor is connected to one end of the second coupling capacitor;
The third variable capacitor is connected to one end of the first coupling capacitor. In claim 2 ,
a third resistor connected in parallel with the first coupling capacitor;
a fourth resistor connected in parallel with the second coupling capacitor;
an ion source comprising: In any one of claims 1 to 3 ,
an ion source including a voltage divider circuit for supplying a voltage obtained by dividing the acceleration voltage to the plasma generation coil; In any one of claims 1 to 4 ,
a Faraday shield disposed between the plasma generating coil and the vacuum vessel;
The accelerating voltage is supplied to the Faraday shield. a vacuum vessel into which a gas is introduced;
a plasma generating coil disposed outside the vacuum vessel and configured to generate plasma in a plasma generating space within the vacuum vessel;
a high frequency power source for supplying a high frequency voltage to the plasma generating coil via a coupling circuit;
an acceleration electrode for accelerating ions generated in the plasma generation space;
an accelerating voltage power supply for supplying an accelerating voltage to the accelerating electrode;
a voltage dividing circuit for supplying a voltage obtained by dividing the acceleration voltage to the plasma generating coil;
Including,
The accelerating voltage is supplied to the plasma generating coil via an impedance element. a vacuum vessel into which a gas is introduced;
a plasma generating coil disposed outside the vacuum vessel and configured to generate plasma in a plasma generating space within the vacuum vessel;
a high frequency power source for supplying a high frequency voltage to the plasma generating coil via a coupling circuit;
an acceleration electrode for accelerating ions generated in the plasma generation space;
an accelerating voltage power supply for supplying an accelerating voltage to the accelerating electrode;
a Faraday shield disposed between the plasma generating coil and the vacuum vessel;
The acceleration voltage is supplied to the plasma generation coil via an impedance element ,
The accelerating voltage is supplied to the Faraday shield . In claim 7,
an ion source including a voltage divider circuit for supplying a voltage obtained by dividing the acceleration voltage to the Faraday shield; In claim 7 or 8,
the potential of the plasma generation coil is lower than the potential of the Faraday shield;
An ion source, wherein the potential of the Faraday shield is lower than the potential of the plasma generation space. An ion beam device including an ion source according to any one of claims 1 to 9.

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