JPH09237700A - High frequency accelerator-decelerator, and usage thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify constitution, and enlarge acceptance to incident energy. SOLUTION: A high frequency accelerator-decelerator 27 is provided with a cylindrical tank 1 having a hollow 2 inside. A first and a second electrodes 3, 4 are disposed in an ion beam passage inside the hollow 2. Three gaps 2a, 2b, 2c are thus formed on the ion beam incident side and outgouing side between an inner wall of the tank 1 and each electrode 3, 4. Each electrode 3, 4 is connected by a first coil 5 or a second coil 6 to a bottom surface 1b of the tank 1. A power input part 8 applies high frequency waves through a power plate 9 disposed close to the second coil 6 to excite both electrodes 3, 4 at similar phases or opposite phases to each other. Since the high frequency accelerator- decelerator 27 has two resonance modes, two synchronized energies can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency accelerating / decelerating device for accelerating / decelerating charged particles such as ion particles, which is provided in, for example, an ion implantation apparatus and a method of using the same.

[0002]

2. Description of the Related Art Currently, integrated circuits using semiconductors are widely used in various fields including electronic devices. In the semiconductor process for manufacturing these integrated circuits, the ion implantation apparatus has become an important apparatus because impurities that determine the characteristics of the device can be implanted at an arbitrary amount and depth with good controllability.

The above-mentioned ion implantation apparatus ionizes the impure gas to be diffused, extracts it at a predetermined acceleration voltage, and selectively extracts it by mass spectrometry using a magnetic field to form an ion beam. Further, the accelerating / decelerating device accelerates or decelerates and irradiates the ion irradiation target object at a desired speed. This makes it possible to implant ions into the object to be ion-irradiated with good controllability.

Examples of the accelerating / decelerating device include an electrostatic accelerating / decelerating device that accelerates / decelerates ions by an electrostatic field formed by applying a DC potential to the electrodes. However, in the electrostatic accelerating / decelerating device, it is necessary to increase the potential of the electrode in order to increase the energy applied to the ion beam, which makes it difficult to use the DC acceleration potential. For example, deep ion implantation into a semiconductor material requires energy up to 2 million electron volts. Therefore, when accelerating using only the electrostatic acceleration / deceleration device, 100
It is necessary to apply a DC voltage exceeding KV. As a result, problems may occur with respect to the size of the accelerating / decelerating device, the amount of beam current, handling, operating performance, and the like.

In such a case, a high frequency acceleration / deceleration device for applying a high frequency to the electrodes is often used. As shown in FIG. 9, the high frequency acceleration / deceleration device 50 includes, for example, a tank 51 in which a conductor such as a metal is formed in a substantially cylindrical shape, and a tank 5.
In the cavity 52 inside 1, there is provided an electrode 53 arranged on the path of the ion beam. As a result, the first gap 52a is formed between the inner wall on the incident side of the ion beam and the electrode 53, and the second gap 52b is formed between the electrode 53 and the inner wall on the emitting side. Further, the electrode 53 is connected to the bottom surface 51b of the tank 51 via the coil 55.
It is connected to the. Therefore, the resonance circuit 50a is formed by the inductance of the coil 55 and the capacitance between the first gap 52a and the second gap 52b. Electric power is supplied to the resonance circuit 50a from an electric power input portion 58 provided outside the tank 51 via an electric power plate 59 in the cavity 52. The power input section 5
The frequency of the RF wave supplied by 8 is set to the resonance frequency of the resonance circuit 50a. Also, the coil 55
When the wavelength of the RF wave is assumed to be λ, the length L when L is extended is set to L≈λ / 4 (1) as shown in the following equation (1).

When ion particles having a positive charge are present in the first gap 52a, the ion particles are accelerated in the traveling direction when the potential of the electrode 53 is lower than the inner wall of the tank 51 on the incident side. Further, when in the second gap 52b, it is accelerated when the potential of the electrode 53 is higher than the inner wall of the tank 51 on the emission side. Therefore, when the ionic particles are in the first gap 52a, the potential of the electrode 53 is lowered, and when the ionic particles progress to the second gap 52b, the potential of the electrode 53 becomes high, Electrode 5
By exciting 3, ion particles can be accelerated.

Therefore, the center of the first gap 52a and the second gap 52b are arranged along the traveling direction of the ion beam.
Assuming that the distance from the center of is dg, as shown below, dg = (1/2) .beta..lamda. In the above equation (2), β is represented by β = v / c, where v is the velocity of ion particles and c is the velocity of light. Further, λ indicates the wavelength of the RF wave.

Further, the synchronous energy E of a certain ion is expressed by E = (1/2) .m.β ² c ² ... (3) as follows.

[0009]

However, in the high frequency accelerating / decelerating device 50 having the above-mentioned configuration, since there is one resonance mode, the resonance frequency, that is, the wavelength λ is limited. Therefore, there is a problem that the synchronous energy E of the ions becomes unitary and the acceptance of the high frequency accelerating / decelerating device 50 with respect to the incident energy is limited.

Therefore, conventionally, when accelerating ion beams having different incident energies, the high frequency acceleration / deceleration device 50 itself is replaced or the gap distance dg is mechanically changed. High frequency accelerator 50
When exchanging itself, it is necessary to prepare a plurality of high-frequency accelerating / decelerating devices 50 ... According to the incident energy of the ion beam. On the other hand, when the gap distance dg is mechanically adjusted, the structure of the high frequency acceleration / deceleration device 50 may be complicated, and the high frequency acceleration / deceleration device 50 may be large. Furthermore, the operation at the time of adjustment becomes complicated.

The present invention has been made in view of the above problems, and an object thereof is to provide a high frequency accelerating / decelerating device having a simple structure and a wide acceptance with respect to incident energy.

[0012]

In order to solve the above-mentioned problems, a high-frequency accelerating / decelerating device according to a first aspect of the present invention includes a resonance circuit including a conductor container having a cavity formed therein, and the resonance circuit. A high-frequency accelerating / decelerating device having a driving means for supplying electric power to is characterized by taking the following means.

That is, the resonance circuit is provided in the cavity and is provided with a plurality of drive electrodes that are excited by the electric power from the drive means. The drive circuit is provided on the path of the charged particles in the cavity. The electrodes for use form three or more gaps.

In the above structure, the driving electrode can be excited by the electric power from the driving means in the same phase or in the opposite phase with the adjacent driving electrode. As a result, the resonance circuit is provided with a plurality of resonance modes.

In a certain resonance mode, when the drive means excites the resonance circuit, a gap between the drive electrodes, which are excited in opposite phases, is used to accelerate or decelerate charged particles such as ions. An electric field is created and the charged particles in the gap are accelerated and decelerated. In addition, each drive electrode is
Since it is excited, the electric field formed between the gaps changes periodically, and the direction thereof is reversed every half cycle. An electric field for acceleration / deceleration is not formed in the gap between the driving electrodes that are excited in the same phase.
Therefore, the charged particles in the gap pass at the original velocity.

When charged particles enter the gap where the acceleration / deceleration electric field is formed, the charged particles pass through the gap while being accelerated / decelerated. If the incident energy of the charged particles is the same as the synchronous energy of the high frequency accelerator,
The timing at which the charged particles pass through the gap is synchronized with the drive cycle of the drive electrode. Therefore, when passing through the gaps, the direction of the electric field formed in the gaps is always constant. As a result, the high frequency acceleration / deceleration device can accelerate / decelerate charged particles having the same incident energy as the synchronization energy with high efficiency.

If the incident energy of the charged particles and the synchronization energy of the high frequency acceleration / deceleration device do not match, the directions of the electric fields formed when passing through the gaps are not uniform, so the high frequency acceleration / deceleration is performed. The container cannot efficiently accelerate or decelerate the charged particles.

Further, each driving electrode is excited, and the strength and direction of the electric field formed in each gap are changed. Therefore, the force applied to the charged particles changes according to the timing at which the charged particles enter the high frequency accelerator.
For example, during a period in which the electric field formed in the gap becomes stronger with time, the charged particles that are incident later on the gap are more strongly accelerated and decelerated than the charged particles that are incident later. As a result, the ejection speed of the charged particles changes according to the timing at which the charged particles enter the high frequency accelerator.
Therefore, the charged particle flow incident on the high frequency accelerator is
It is bunched when it passes through a predetermined space (drift space).

In the above high-frequency accelerating / decelerating device, a plurality of driving electrodes are arranged on the path of the charged particles to form three or more gaps, and a plurality of gaps are formed without mechanically displacing the structure. It can be operated in the resonance mode of. Therefore, a plurality of synchronous energies of the high frequency acceleration / deceleration device are provided corresponding to the resonance modes. As a result, even a plurality of charged particles having different incident energies can be accelerated or decelerated or bunched, and the acceptance of the high frequency accelerating / decelerating device with respect to the incident energy can be widened as compared with the conventional case.

Further, the ratio of the number of gaps to the number of containers can be increased as compared with the conventional high frequency accelerating / decelerating device. Therefore, when the same number of gaps are provided, the number of containers, driving means for driving the containers, support members for supporting the containers, and the like can be reduced, and the configuration can be simplified.

In addition, if the number of gaps is the same, the number of container walls provided between the driving electrodes can be reduced. Therefore, the ratio of the acceleration / deceleration voltage to the electric power input to the high frequency acceleration / deceleration device can be made higher than in the conventional case, and the efficiency of the high frequency acceleration / deceleration device can be further improved.

According to a second aspect of the present invention, in the high-frequency acceleration / deceleration device according to the first aspect of the invention, the driving means has a fundamental frequency of each resonance mode of the resonance circuit.
It is characterized in that the resonance circuit is driven.

Therefore, the resonance circuit can resonate at a low resonance frequency that is advantageous for ion acceleration / deceleration. As a result, in the high-frequency accelerating / decelerating device, more synchronous energy, which is advantageous for accelerating / decelerating the ions, can be provided than in the conventional case.

On the other hand, in the method of using the high frequency acceleration / deceleration device according to the invention of claim 3, a plurality of high frequency acceleration / deceleration devices according to claim 1 are arranged in series, and the first stage is operated as a bunching part for bunching charged particles. The second and subsequent stages are characterized by operating as an acceleration / deceleration unit that accelerates / decelerates the charged particles.

In the above structure, the high frequency acceleration / deceleration device having the same structure can be used to accelerate and decelerate after bunching the charged particles. Therefore, the bunching part and the acceleration / deceleration part have the same structure, and the same member can be used. As a result, it becomes easier to manufacture and manage the device including the bunching part, as compared with the case where the bunching means having another structure is provided.

Further, even when the synchronous energy of the high frequency acceleration / deceleration device is adjusted, that is, when the resonance mode of the acceleration / deceleration unit is changed, the same operation as that of the acceleration / deceleration unit is performed.
The resonance frequency of the bunching part can be matched with the resonance frequency of the acceleration / deceleration part. As a result, the operability of the high frequency acceleration / deceleration device at the time of adjusting the synchronous energy is improved.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention.
7 is as follows. The high frequency acceleration / deceleration device according to the present embodiment is used for a high energy ion implantation device such as a semiconductor manufacturing device or a surface modification irradiation device, and is used for bunching and accelerating ions.

As shown in FIG. 2, the ion implanter 2
Reference numeral 1 denotes an ion source 22 for ionizing an ion source substance, an analyzing electromagnet 23 for mass-analyzing ions having a predetermined energy extracted from the ion source 22, and the analyzing electromagnet 2
Electrostatic accelerator 2 for accelerating the ion beam formed in 3.
4 and a focusing system 25 for focusing the ion beam after acceleration,
A buncher (bunching portion) 26 for bunching the focused ion beam. further,
A high-frequency acceleration / deceleration device (acceleration / deceleration unit) 27 that is connected in series with each other and further accelerates the bunched ion beam;
There is provided an end station 28 for processing a stored ion irradiation target object such as a silicon wafer by an incident ion beam. Further, during the operation of the ion implantation device 21, the passage of the ion beam is kept in a high vacuum by a vacuum pump or the like not shown. In addition, in this embodiment, the buncher 26 and the high frequency acceleration / deceleration device 27 have the same configuration, and both correspond to the high frequency acceleration / deceleration device described in the claims.

The ion source 22 is, for example, a high frequency discharge type or electron collision type ion source, and is, for example, BF ₃
Ionic species gas such or PH ₃ or, vaporizing ion source material of a solid, such as P or As in an oven, are introduced into the ion source 22. After that, the ion species gas inside can be turned into plasma, extracted with a predetermined energy by the ion extraction electrode system, and given to the analysis electromagnet 23 as ions such as B ⁺ and P ⁺ .

The analyzing electromagnet 23 is, for example, 60 °.
Type and 90 ° type fan magnets are used, and an ion beam composed of desired ions can be formed by mass analysis.

Further, the electrostatic accelerator 24 arranged in the latter stage of the analyzing electromagnet 23 is, for example, a Cockloft type electrostatic accelerator, and the analyzing electromagnet 23 side which is upstream of the ion beam and the focusing system 25 which is downstream thereof. The incident ion beam is accelerated by the electrostatic field generated by the potential difference from the side. Therefore, during operation of the ion implanter 21, the analysis electromagnet 2
3 and the ion source 22 are kept at a much higher potential than other circuits such as the focusing system 25. Further, in order to protect the user and other circuits, the analyzing electromagnet 23 and the ion source 22 are housed in a high voltage cabinet 29 that is electrically insulated from other circuits.

The ion implanter 21 according to this embodiment is
A high frequency acceleration / deceleration device 27 is provided after the electrostatic accelerator 24. Therefore, the energy of the ion beam emitted by the electrostatic accelerator 24 is set lower than the energy of the ion beam required at the end station 28. As a result, the potential of the high voltage cabinet 29, that is, the acceleration voltage of the electrostatic accelerator 24 is set to be lower than that in the case where the electrostatic accelerator 24 alone accelerates.

A buncher 26 disposed after the electrostatic accelerator 24 via a focusing system 25 adjusts the acceleration applied to each ion particle according to the incident time of the ion particle to bunching the ion particle. Let Specifically, for every predetermined period, the ion particles that are late entering are accelerated more largely than the ion particles that are early entering, based on a certain time point. As a result, ionic particles can be bunched in a predetermined space (drift space) from the exit side of the buncher 26. The buncher 26 according to the present embodiment has the same configuration as a high frequency acceleration / deceleration device 27 described later. Therefore, the description of the configuration of the buncher 26 is omitted.

In the high-frequency accelerating / decelerating device 27 in the latter stage of the buncher 26, the ion particles emitted from the buncher 26 are
It is arranged at a bunching position in an entrance hole 1c (described later) of the high-frequency acceleration / deceleration device 27. Further, the drive frequency of the buncher 26 and the drive frequency of the high frequency accelerating / decelerating device 27 are set to be the same. Further, the phase difference between the two is that the bunched ion particle group is the incident hole 1c of the high frequency accelerator 27.
It is set so that an electric field for acceleration is formed when the vehicle enters.

As shown in FIG. 3, the high frequency acceleration / deceleration device 27 is provided with a substantially cylindrical tank (container) 1. For convenience of explanation, a wall surface parallel to the axial direction of the tank 1 is a side surface 1a, and one wall surface orthogonal to the side surface 1a is a bottom surface 1b.
Called. The path of the ion beam is set so as to be orthogonal to the axis of the tank 1, and the side surface 1 of the tank 1 is
In a, an entrance hole 1c and an exit hole 1d, which have a circular cross section, are provided along the path of the ion beam so as to communicate with the inner cavity 2. In the tank 1, the inner wall in the vicinity of both holes 1c and 1d is provided so as to protrude from the inner wall of the other portion, and is formed in a cylindrical shape with the path of the ion beam as an axis. The tips of the respective convex portions are respectively connected to the entrance side inner wall 1e and the exit side inner wall 1e.
Called f.

Further, a first electrode 3 and a second electrode 4 which are excited by a high frequency and which correspond to the driving electrodes described in the claims are arranged on the ion beam passage of the cavity 2 in the tank 1. ing. Therefore, as shown in FIG. 1, the first gap 2a between the incident-side inner wall 1e and the first electrode 3,
Second gap 2b between both electrodes 3 and 4, and second electrode 4
And a third gap 2c between the incident side inner wall 1f and the incident side inner wall 1f. As a result, the resonance circuit 27a is formed by the capacitance between the gaps 2a, 2b and 2c and the inductance of the first coil 5 and the second coil 6 which will be described later. As a result, since the two electrodes 3 and 4 are excited at a high frequency, the resonance circuit 27a excites both electrodes 3 and 4 in the same phase without mechanically displacing the constituent elements. "
It can resonate in two mutually different resonance modes, that is, a "0" mode and a "π" mode that is excited in an opposite phase.

In the following, when measured along the path of the ion beam, the center of the first gap 2a and the second gap 2b are measured.
, Dg1, the distance between the center of the second gap 2b and the center of the third gap 2c, and dg0 the distance between the center of the first gap 2a and the center of the third gap 2c. Distance between each gap dg0 ・ dg1 ・ dg
2 is determined by a combination of energy of incident particles, discharge limit, resonance frequency, etc., wavelength in "π" mode is λπ, synchronization βs is βsπ, wavelength in "0" mode is λ0, synchronization βs is βs0. At this time, the distances dg0, dg1, and dg2 between the gaps are expressed by the following equations (4) and (5): dg0 = (1/2) .beta.s0.lambda.0 (4) dg1 = dg2 = (1 / 2) · βsπ · λπ (5) The electrodes 3 and 4 are arranged such that the gap distances dg0, dg1, and dg2 have desired values.

Each of the electrodes 3 and 4 called a drift tube is formed in a substantially disc shape, and its center is
Through holes 3a and 4 having a circular cross section that serves as a passage for the ion beam
a are formed respectively. Also, both electrodes 3 and 4
Are respectively connected to the first coil 5 or the second coil 6 projecting from the bottom surface 1b of the tank 1. Holes for circulating a cooling liquid such as water are formed in the conductors of the coils 5 and 6, and during operation of the high frequency acceleration / deceleration device 27, a large current flows and each coil tends to become particularly high in temperature. 5
The vicinity of the bottom surface 1b of 6 can also be cooled.

Further, the coils 5 and 6 are provided in the tank 1
The electrode side is supported by the support bodies 7 and 7 protruding from the side surface 1a. Each support 7 is, for example, B
It is formed in a thin plate shape with a material such as N and ceramic having high electric resistance and low dielectric loss. Further, for example, as shown in FIG. 4, a hole 7a having an inner diameter substantially the same as the outer diameter of the first or second coil 5 or 6 is formed at the tip of the support body 7, and each of the holes shown in FIG. The coils 5 and 6 are inserted into the hole 7a. As a result, the vibrations of the coils 5 and 6 can be suppressed, and the electrodes 3 and 4 can be held at predetermined positions. As a result, the gap distances dg0, dg1, and dg2 can be maintained at desired values.

Here, the dimensions of the high frequency acceleration / deceleration device 27 according to this embodiment will be briefly described. That is, the tank 1 has an inner diameter of 14 cm and an axial inner dimension of 45 cm. The outer diameter of both electrodes 3 and 4 is 2.5 cm.
Is set to When the electrodes 3 and 4 are arranged at predetermined positions, the distance between the entrance-side inner wall 1e of the tank 1 and the first electrode 3, the distance between the electrodes 3 and 4, and the second electrode 4 and The distance between the emission side inner walls 1f is 1c, respectively.
m. Therefore, the gap distance dg
0 is 2 cm, the distance between both gaps dg1 and dg2 is 1
Each is kept in cm. Also, both coils 5 and 6
Is a copper wire having an outer diameter of 1 mm and a length of 3 m, which is wound to have an outer diameter of 3 cm.

In the case of the cold model having the above dimensions, the resonance frequency of the "π" mode is 25 MHz and "0".
The resonance frequency of the mode is 31 MHz. Therefore, the wavelength λπ · λ0 of each mode is, as shown below,
Respectively, the λπ = 1.2 × 10 ³ (cm) ··· (6) λ0 = 9.7 × 10 2 [cm] (7).

From the above equations (4) and (5), the ratio dg0 / dg1 of the gap distance dg0 in the "0" mode to the gap distance dg1 in the "π" mode is 2. From this ratio and the above equation (2), the ratio of the synchronization βs between the modes is βs0 / βsπ = 2 · λπ / λ0 (8) as shown in the following equation (8), Further, by substituting the values of (6) and (7) above, βs0 / βsπ = 2.47 (9).

Similarly, from the above equation (3), the ratio of the synchronous Es in each mode is Es0 / Esπ = (βs0 / βsπ) ² (10) Es0 / Esπ = 6.1. (11) Therefore, for example, when Esπ = 50 KeV, Es0≈300 KeV.

On the other hand, outside the tank 1, a power input section (driving means) 8 for supplying power for exciting the resonance circuit 27a is provided. The power input unit 8 is
High-frequency power can be supplied to the power plate 9 inside the tank 1 through the power field through 1g provided on the side surface 1a of the tank 1. The high frequency accelerating / decelerating device 27 according to the present embodiment has two resonance frequencies in a frequency band suitable for ion acceleration. Therefore, the power input unit 8 can select and output the RF wave of each resonance frequency such as 31 MHz and 25 MHz. As a result, the resonance circuit 27a can be excited at each resonance frequency.

The power plate 9 faces the electrode side end of the second coil 6 and is arranged at intervals of several centimeters. The power plate 9 can be moved by a control motor (not shown) or the like to adjust the distance from the second coil 6. With the movement of the power plate 9, the coupling capacitance between the second coil 6 and the power plate 9 changes. As a result, the input impedance of the resonance circuit 27a is maintained at a desired value such as 50Ω,
The impedance matching between the resonance circuit 27a and the power input unit 8 can be maintained.

Further, the high frequency accelerating / decelerating device 27 is constituted by the resonance circuit 2
A frequency tuner 10 provided outside the tank 1 and a tuner plate 11 provided in the cavity 2 in the tank 1 are provided for finely adjusting the resonance frequency of the tank 7a.
The tuner plate 11 has a bottom surface 1b of the second coil 6.
It is provided opposite to the side end. Frequency tuner 10
Displaces the tuner plate 11 between the second coil 6 and the side surface 1a via the tuner field through 1h. As a result, the floating capacitance with respect to the ground potential can be adjusted to finely adjust the resonance frequency of the resonance circuit 27a. As a result, the resonance frequency can be precisely adjusted, or the resonance frequency can be maintained when, for example, the first coil 5 or the second coil 6 is heated and the dimensions thereof are changed.

Further, the end station 2 shown in FIG.
An ion irradiation target, such as a silicon wafer, is placed in the path 8 of the ion beam emitted from the high-frequency accelerating / decelerating device 27. As a result, it is possible to irradiate the ion irradiation target with ions to implant impurities and modify the surface.

In the above structure, the operation of each part of the buncher 26 in the "π" mode will be described with reference to FIGS.
The following is a description based on.

When the buncher 26 is operated in the "π" mode, the power input section 8 shown in FIG.
The resonance circuit 26a of the buncher 26 is driven at a resonance frequency of "π" mode such as MHz. In this state, the electric power plate 9 is adjusted in distance from the second coil 6 by a control motor (not shown). Thereby, the impedance matching between the power input unit 8 and the resonance circuit 26a is maintained. In addition, the frequency tuner 10
Controls the position of the tuner plate 11 to maintain the resonance frequency of the resonance circuit 26a at a predetermined value.

As a result, as shown in FIG. 5, the first electrode 3
And the second electrode 4 is excited in different phases. Therefore, for example, the potential of the first electrode 3 is −,
The electric field inside the buncher 26 when the potential of the electrode 4 is + is the same as the traveling direction of the ion beam (forward direction) in the first gap 2a and the third gap 2c as shown by the solid line in the figure. In the second gap 2b, the direction is opposite to the traveling direction of the ion beam (hereinafter, simply referred to as the opposite direction). On the other hand, when the electric potential of the first electrode 3 is + and the electric potential of the second electrode 4 is −, the electric field is in the opposite direction in the first gap 2a and the third gap 2c as shown by the broken line in the figure. , In the second gap 2b in the forward direction.

Further, at a point A on the path of the ion beam in the first gap 2a, the time change of the electric field intensity E in the traveling direction of the ion beam becomes a sine wave of the resonance frequency as shown in FIG. ing. Therefore, assuming that the time point rising with time changes is t0, the electric field strength E0 at time t0 is stronger than the electric field strength E1 at time t1 immediately before time t0, and is higher than the electric field strength E2 at time t2 immediately after time t0. Also becomes weaker. As a result, when the ion particle at point A at time t0 is used as a reference, point A at time t2
Ionic particles in
It is much more accelerated than the faster ionic particles. Therefore, the ion particles emitted from the buncher 26 are
Bunching is performed at a place separated from a certain space, that is, at the entrance of the high frequency acceleration / deceleration device 27. The buncher 26
Since it is driven at a predetermined resonance frequency, a sparse portion and a dense portion alternately appear in the ion beam incident on the high frequency accelerating / decelerating device 27 in synchronization with this resonance frequency.

In the high-frequency accelerating / decelerating device 27, as in the buncher 26, the power input unit 8 causes the resonance circuit 27 to operate at the resonance frequency in the "π" mode such as 25 MHz.
a is being driven. Further, the phase difference between the buncher 26 and the high-frequency accelerator / decelerator 27 in the preceding stage is set so that the applied electric field is in the forward direction while the bunched ion particles pass through the first gap 2a. .

Therefore, until the bunched ion particle group enters the first gap 2a through the entrance hole 1c and reaches the first electrode 3, the electric field in the first gap 2a is in the forward direction ( The state of the solid line shown in FIG. 5). As a result, the ion particle group is further accelerated and reaches the first electrode 3. In addition, the time during which the ion particles are flying in the first gap 1a and the time when the polarity of the first electrode 3 is reversed are substantially the same, that is, the incident energy of the ion particles and the synchronous energy Esπ are the same. Thus, the resonance frequency of the resonance circuit 27a is determined. As a result, the above-mentioned ionic particle group passes through the through hole 3a shown in FIG.
The electric field in the first gap 1a is in the reverse direction and the electric field in the second gap 2b is in the forward direction until it reaches the second electrode 4 after entering the second gap 2b (state shown by broken line in FIG. 5). ). Therefore, the ion particle group is further accelerated and reaches the second electrode 4. Similarly, the ion particle group is accelerated even in the third gap 2c. As a result, the high frequency accelerating / decelerating device 27 is configured so that each gap 2a
Accelerate the ion particle group that entered at 3 gap of 2c,
It can be emitted from the emission hole 1d.

Next, the operation of the high frequency acceleration / deceleration device 27 in the "0" mode will be described with reference to FIG. The operation of the buncher 26 in the "0" mode has the same electric field distribution as that of the high-frequency accelerating / decelerating device 27, and the operation of the charged particles in each gap is substantially the same as the operation in the "π" mode. , Description is omitted.

Similar to the above "π" mode, the power input section 8 shown in FIG. 1 drives the resonance circuit 27a at the resonance frequency in the "0" mode such as 31 MHz. In this mode, unlike the above "π" mode, both electrodes 3
No. 4 is exciting in the same phase. Therefore, both electrodes 3
When both 4 are at a negative potential, a forward electric field is formed in the first gap 2a and a reverse electric field is formed in the third gap 2c, as indicated by the solid line in FIG. ing. When both electrodes 3 and 4 are both at the positive potential, electric fields in the reverse direction and the forward direction are formed in the first gap 2a and the third gap 2c, respectively, as indicated by the broken line in the figure. ing. In either case, both electrodes 3 and 4
Since the electric potentials of are the same, no acceleration electric field is formed in the second gap 2b.

When a forward electric field is formed in the first gap 2a, the synchronization energy E of the high frequency acceleration / deceleration device 27 is generated.
When an ion particle group having the same incident energy as s0 is incident, the ion particle group reaches the first electrode 3 while being accelerated, and reaches the second electrode 4 while maintaining the same speed. Further, the ionic particle group has a third gap 2c.
At the time of entering, the electric potentials of both electrodes 3 and 4 are inverted, and a forward electric field is formed in the third gap 2c. Therefore, this ion particle group is further accelerated and emitted from the emission hole 1d. As a result, the high frequency acceleration / deceleration device 27
Can accelerate incident ion particles in the two gaps, the first gap 2a and the third gap 2c, and eject them from the emission hole 1d.

In the above, only the case of accelerating in each mode has been described, but when the ion particle group is incident on the high frequency accelerator / decelerator 27, an electric field in the opposite direction is formed in the first gap 2a. The ion particle group can be decelerated by adjusting the phase difference between the buncher 26 and the high frequency acceleration / deceleration device 27. Moreover, even when the charge of the accelerating / decelerating ion particles is negative, the ion particle group can be similarly accelerated / decelerated.

Further, in any of the modes of operation, when the synchronous energy Es of the high-frequency accelerating / decelerating device 27 and the incident energy of the ion particle group are different, the ions between the gaps 2a, 2b and 2c are separated. The flying time of the particle group and the inverting time of both electrodes 3 and 4 are different. Therefore, while the ion particle group is flying in the gap, the electric field formed in the gap is reversed, or the ion particle group passes through the gap in which the forward electric field is formed and the reverse electric field is formed. The ion particle group cannot be normally accelerated by rushing into another gap that has been created.

As described above, the high frequency acceleration / deceleration device 27 according to this embodiment has the tank 1 having a high conductivity in the cavity 2 in the tank 1 along the path of the ion beam via the first coil 5. The first electrode 3 connected to the tank 1 and the second electrode 4 connected to the tank 1 via the second coil 6 are arranged.
Between the inner wall of the electrode and both electrodes 3 and 4, three gaps 2a,
2b and 2c are formed, and a power input section 8 for exciting both electrodes 3 and 4 at a high frequency is provided.

Therefore, the tank 1, both electrodes 3 and 4,
And a resonance circuit 27 composed of both coils 5 and 6
A can resonate in two resonance modes, a "π" mode in which both electrodes 3 and 4 are excited in opposite phases and a "0" mode in which they are excited in the same phase.

For example, the power input unit 8 is the resonance circuit 27a.
When operating in "π" mode, each gap 2a
An electric field having a direction different from that of the adjacent gap is formed in 2b and 2c. Therefore, the high frequency acceleration / deceleration device 27
Can efficiently accelerate or decelerate an ion beam having the same incident energy as the synchronous energy Esπ in the three gaps. When the resonance circuit 27a is operated in the "0" mode, electric fields having different directions are formed in the gaps 2a and 2c at both ends, and the second gap 2b in the middle is for acceleration / deceleration. Electric field is not formed. Therefore, the high frequency acceleration / deceleration device 27 can efficiently accelerate / decelerate the ion beam having the same incident energy as the synchronous energy Es0 in the two gaps at both ends.

On the other hand, in any mode, the strength and direction of the formed electric field periodically change. Therefore, the buncher 26 having the same structure as the high frequency accelerator 27
Can change the force applied to the ionic particles according to the incident timing of the ionic particles to change the speed at the time of emission. As a result, the buncher 26 places the incident ion beam in the drift space while leaving the drift space.
Bunching can be performed at the driving frequency of.

In any mode, the high-frequency accelerating / decelerating device 27 efficiently accelerates / decelerates the ion beam when an ion beam having an incident energy different from the synchronous energy Es during operation is incident. Can't bunching. Therefore, it is necessary to set the synchronous energy Es of the high-frequency accelerating / decelerating device 27, that is, the resonance frequency of the resonance circuit 27a according to the incident energy of the ion beam.

In the conventional high-frequency acceleration / deceleration device, since only one resonance mode of the resonance circuit is provided, the settable resonance frequency is limited. Therefore, in order to flexibly change the synchronous energy Es within a range suitable for accelerating and decelerating the ion beam, a plurality of high-frequency accelerating / decelerating devices having different synchronous energies Es are prepared and exchanged in accordance with the ion beam. The position of a member forming the high frequency acceleration / deceleration device is mechanically displaced to adjust the resonance frequency of the resonance circuit.

However, in the high frequency acceleration / deceleration device 27 according to the present embodiment, the resonance frequency is changed by changing the resonance mode of the resonance circuit 27a without mechanically changing the components of the high frequency acceleration / deceleration device 27. Mainly adjustable. Since the high-frequency acceleration / deceleration device 27 can be provided with two points of the synchronization energy Es, the synchronization energy Es can be flexibly changed as compared with the conventional case.

As a result, acceleration / deceleration or bunching effect can be obtained even with ion particle groups having different velocities. The beam energy emitted from the electrostatic accelerator 24 shown in FIG. 2 is proportional to the number of charges, and for example, a hexavalent ion particle has six times the energy of a monovalent ion particle. Even in such a case, the acceleration / deceleration or the bunching action can be obtained by using the high-frequency acceleration / deceleration device 27 having the same structure. Therefore, it is possible to realize the high frequency accelerating / decelerating device 27 having a wider acceptance for incident energy than the conventional one.

Further, the high frequency acceleration / deceleration device 2 according to the present embodiment.
In No. 7, no mechanical adjustment is required when the resonance frequency is mainly adjusted. Therefore, the structure of the high-frequency accelerating / decelerating device 27 can be simplified and the time and effort required for the main adjustment can be greatly reduced.

Further, the high-frequency acceleration / deceleration device 27 is different from the conventional two-gap type high-frequency acceleration / deceleration device in the tank 1.
The ratio of the number of gaps to the number of can be increased. Therefore, when the same number of gaps are provided, the number of the tank 1, the power input unit 8, or a support member (not shown) that supports the tank 1 can be reduced, and the configuration of the ion implantation device 21 can be simplified.

In addition, the number of walls with respect to the number of gaps can be reduced as compared with the two-gap method. For example, as in the high frequency acceleration / deceleration device 27 according to the present embodiment, 3
If two gaps are to be provided, conventionally, two high frequency accelerating / decelerating devices are required, and the wall of the tank is interposed between the second gap and the third gap, counting from the incident side. However, in the present embodiment, this wall is unnecessary, and the distance between the gaps can be shortened. As a result, the ratio of the input power to the acceleration voltage can be increased, and the efficiency of the high frequency acceleration / deceleration device 27 can be improved.

In addition, the power input section 8 includes the resonance circuit 27.
It is desired to drive the resonance circuit 27a at the fundamental frequency of each resonance mode provided in a. This allows
The resonance circuit 27a can resonate at a low resonance frequency that is advantageous for acceleration / deceleration of ions. Therefore, the high frequency acceleration / deceleration device 27
Can be provided with more synchronous energy Es, which is advantageous for ion acceleration / deceleration, than in the conventional case. As a result, the high frequency acceleration / deceleration device 27 particularly suitable for accelerating / decelerating or bunching the ion beam.
Can be provided.

In this embodiment, the buncher 26 has the same structure as the high frequency accelerating / decelerating device 27, but the buncher 26 is not limited to this. For example, R described later
A bunching device having another configuration such as FQ may be used.

However, by making the buncher 26 and the high-frequency accelerating / decelerating device 27 have the same structure as in the present embodiment, manufacturing and management are easier than when a bunching device having a different structure is provided. . For example, since both have the same configuration, the same member can be used, and a member prepared for a defect or the like can be used.

Further, even when the synchronous energy Es of the high frequency acceleration / deceleration device 27 is adjusted according to the energy of the incident ion beam, that is, when the resonance frequency is changed, the buncher 26 is similar to the high frequency acceleration / deceleration device 27. To
The resonance frequency can be adjusted by changing the resonance mode. As a result, both frequencies can be easily set to the same, and the operability when adjusting the synchronization energy Es is improved.

Further, in the present embodiment, the buncher 26 and the high frequency accelerating / decelerating device 27 are arranged downstream of the electrostatic accelerator 24 and are used as an energy booster. Thereby, energy higher than the energy of the ion beam emitted by the electrostatic accelerator 24 can be supplied to the end station 28. By the way, in the case of accelerating the ion beam by the electrostatic accelerator 24 alone, a high acceleration voltage is required to obtain high energy, and therefore the potential inside the high voltage cabinet 29 needs to be kept high. Along with this, the size of the high-voltage cabinet 29 and the high-voltage power supply (not shown) that supplies power to the high-voltage cabinet 29 are increased. However, by using the high frequency acceleration / deceleration device 27 as an energy booster of the electrostatic accelerator 24, the electrostatic accelerator 24 is stable and has less aberration.
Ion implantation with high energy, and
A compact ion implanter 21 can be realized. Also,
In the high energy ion implanter, the electrostatic accelerator 2 is used.
Since the accelerating voltage of No. 4 can be suppressed low, the device cost can be reduced, and the beam current amount, handling, operating performance, etc. can be improved.

In this embodiment, the gap distances dg1 and dg2 are set to be the same, but the present invention is not limited to this. Ion particles have gaps 2a, 2b, 2
Strictly speaking, if the gap distances dg1 and dg2 are set to be the same, the time required to pass the preceding gap and the time required to pass the subsequent gap differ. In this embodiment, since there is no hindrance to the acceleration / deceleration of the ion beam, the distances dg1 and dg2 between the two gaps are set to be the same from the viewpoint of labor in designing and manufacturing. However, when the time required for the gap in the front stage and the time required for the gap in the rear stage are significantly different and there is a hindrance to the acceleration / deceleration of the ion beam, the gap distances dg1
By setting dg2 separately and suppressing the difference in the required time of both gaps, the ion beam can be accelerated and decelerated without any trouble.

Further, the high frequency acceleration / deceleration device 2 according to the present embodiment.
7 includes two electrodes 3 and 4 and forms three gaps 2a, 2b and 2c in the cavity 2, but the number of electrodes is not limited to this. Multiple electrodes are provided,
If three or more gaps are formed, the same effect as this embodiment can be obtained.

For example, the number of electrodes may be set to three and four gaps may be provided. In this case, the high frequency acceleration / deceleration device has an f2 mode in which all three electrodes are excited in the same phase,
F0 mode in which the electrodes on both ends are excited in the same phase and the intermediate electrodes are excited in the opposite phase, f1 in which the first two electrodes are excited in the same phase and the last electrode is excited in the opposite phase when viewed from the path direction of the ion beam Equipped with three modes, synchronous energy E
s can be provided at three points. As a result, as compared with the case where two electrodes are provided, the acceptance of the high frequency acceleration / deceleration device with respect to the incident energy is further improved, and the ratio of the acceleration voltage to the input power can be further increased.

Next, a case where the high frequency accelerating / decelerating device 27 is applied to an ion implanter having another structure will be described with reference to FIG. Members having the same functions as those shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

The ion implanter 21a according to this embodiment.
2 is equipped with an RFQ 30 which can remove the electrostatic accelerator 24 of the ion implantation apparatus 21 shown in FIG. 2 and replace the buncher 26 with bunching, focusing and acceleration of an incident ion beam.

The RFQ 30 has four transmission lines arranged so as to surround the path of the ion beam. Two pairs of Q electrodes that oppose each other on a diagonal line form a resonator that is coupled by the capacitance between the electrodes and the inductance of the post that supports the electrodes. These resonators resonate in the "π" mode, so that a large-current DC beam can be efficiently transmitted. Good and compact bunching, focusing and acceleration.

In the above-mentioned structure, like the high frequency acceleration / deceleration device 27 shown in FIG. 2, the high frequency acceleration / deceleration device 27 is arranged at a position where the ion particles emitted from the RFQ 30 are bunched.
By adjusting the phase difference between the high frequency acceleration / deceleration device 30 and the high frequency acceleration / deceleration device 27, the high frequency acceleration / deceleration device 27 can accelerate the ion beam from the RFQ 30.

Unlike the ion implanter 21 shown in FIG. 2, the ion implanter 21a according to this embodiment uses an RFQ 30 instead of the electrostatic accelerator 24. Therefore, compared with other members such as the high-frequency accelerating / decelerating device 27, the ion source 22 and the analyzing electromagnet 23 can be accelerated by bunching the ion beam without particularly maintaining a high potential. As a result, a high-voltage power supply (not shown) for supplying the acceleration potential to the electrostatic accelerator 24 becomes unnecessary. Further, like the ion implanter 21, the ion source 22 and the analyzing electromagnet 2 are
Since it is not necessary to store 3 in the high voltage cabinet 29, the configuration of the ion implantation device 21a can be further simplified. Further, in the present embodiment, the ion source 22 and the analyzing electromagnet 23 do not have a high potential, so that the ion source 22 and the analyzing electromagnet 23 are easily handled. As a result,
It is possible to realize a compact ion implanter 21a capable of implanting ions with high energy.

In each of the above-mentioned embodiments, for example, two high frequency acceleration / deceleration devices 27 are provided in series to sequentially accelerate the ion beam, but the number of high frequency acceleration / deceleration devices 27 is not limited to this. Absent. It may be used alone, or three or more may be provided in series. The number of the high frequency accelerating / decelerating devices 27 can be arbitrarily set according to the energy of the ion beam required at the end station 28.

The high-frequency accelerating / decelerating device 27 is not limited to the ion implanting device 21 (21a) having the configuration shown in each of the above-described embodiments, but can be applied to the ion implanting devices having other configurations. Also,
In each of the above-described embodiments, the high-frequency accelerating / decelerating device 27 is used for accelerating / decelerating ions or bunching, but the invention is not limited to this. For example, it can be used for acceleration / deceleration or bunching of other charged particles such as electrons. However, ions have various incident energies because they are rich in electric charge and mass. As a result, as shown in each of the above embodiments, the high frequency accelerating / decelerating device 27 having a wide acceptance with respect to the incident energy is particularly suitable for the treatment of ions.

[0085]

As described above, in the high frequency accelerating / decelerating device according to the first aspect of the present invention, the resonance circuit is arranged in the cavity formed inside the conductor container and is excited by the electric power from the driving means. Drive electrodes are provided, and three or more gaps are formed by the drive electrodes on the passage of the charged particles in the cavity.

Therefore, a plurality of synchronous energies of the high frequency acceleration / deceleration device are provided corresponding to each resonance mode without mechanically displacing the structure of the high frequency acceleration / deceleration device. As a result, it is possible to widen the acceptance of the high frequency acceleration / deceleration device with respect to the incident energy, as compared with the conventional case.

If the number of gaps is the same, the number of container walls provided between the drive electrodes can be reduced. Therefore, the ratio of the acceleration / deceleration voltage to the electric power input to the high frequency acceleration / deceleration device can be made higher than in the conventional case, and the efficiency of the high frequency acceleration / deceleration device can be further improved.

The high frequency acceleration / deceleration device according to the invention of claim 2 is
As described above, in the configuration according to the first aspect of the present invention, the driving means drives the resonant circuit at the fundamental frequency of each resonant mode of the resonant circuit.

Therefore, in the high frequency accelerating / decelerating device, more synchronous energy, which is advantageous for accelerating / decelerating the ions, can be provided than in the conventional case. As a result, it is possible to realize a high-frequency accelerating / decelerating device that is particularly suitable for accelerating / decelerating or bunching the ion beam.

In the method of using the high frequency acceleration / deceleration device according to the invention of claim 3, as described above, a plurality of high frequency acceleration / deceleration devices according to claim 1 are arranged in series, and the first stage is a bunching part for bunching charged particles. The second and subsequent stages are configured to operate as an acceleration / deceleration unit that accelerates / decelerates the charged particles.

In the above structure, since the bunching part and the acceleration / deceleration part can be realized by the high-frequency acceleration / deceleration device having the same structure,
As compared with the case where the bunching portion having another configuration is provided, the effect of facilitating the manufacturing and management of the device including the bunching portion is exerted. Further, since the both configurations are the same, there is an effect that the operability of the high frequency acceleration / deceleration device at the time of adjusting the synchronous energy can be improved.

[Brief description of drawings]

FIG. 1 illustrates an embodiment of the present invention and is a configuration diagram illustrating a main part of a high-frequency acceleration / deceleration device.

FIG. 2 is a configuration diagram showing an ion implantation apparatus provided with the above-described high-frequency accelerator / decelerator.

FIG. 3 is a perspective view showing the vicinity of a container of the high frequency acceleration / deceleration device.

FIG. 4 is a plan view showing a coil supporting member provided in the high-frequency acceleration / deceleration device.

FIG. 5 is an explanatory diagram showing an electric field between electrodes in the “π” mode in the high frequency acceleration / deceleration device.

FIG. 6 is a graph showing a temporal change of electric field strength at a certain point in a container in the high frequency acceleration / deceleration device.

FIG. 7 is an explanatory diagram showing an electric field between electrodes in a “0” mode in the high frequency acceleration / deceleration device.

FIG. 8 shows another embodiment and is a configuration diagram showing an ion implantation apparatus including the high-frequency accelerating / decelerating device.

FIG. 9 illustrates a conventional example and is a configuration diagram illustrating a main part of a high-frequency acceleration / deceleration device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank (container) 2 Cavity 2a 1st gap 2b 2nd gap 2c 3rd gap 3 1st electrode (driving electrode) 4 2nd electrode (driving electrode) 8 Power input part (driving means) 26 Buncher (high frequency application) Decelerator: bunching part) 27 High-frequency acceleration / deceleration device (high-frequency acceleration / deceleration device: acceleration / deceleration part) 27a Resonance circuit

Claims (3)

[Claims] 1. A high frequency acceleration / deceleration device having a resonance circuit including a conductor container having a cavity formed therein, and a drive means for supplying electric power to the resonance circuit, wherein the resonance circuit is provided in the cavity. A plurality of driving electrodes arranged to be excited by electric power from the driving means are provided, and three or more gaps are formed by the driving electrodes on the passage of the charged particles in the cavity. A high-frequency acceleration / deceleration device characterized in that 2. The high frequency acceleration / deceleration device according to claim 1, wherein the driving means drives the resonance circuit at a fundamental frequency of each resonance mode of the resonance circuit. 3. A plurality of high-frequency acceleration / deceleration devices according to claim 1 are arranged in series, the first stage is operated as a bunching unit for bunching charged particles, and the subsequent stages are as acceleration / deceleration units for accelerating / decelerating charged particles. The method of using the high frequency acceleration / deceleration device according to claim 1, wherein the high frequency acceleration / deceleration device is operated.