JP2002248429A - Ultrasonic oscillation device and ultrasonic oscillation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic wave oscillation apparatus capable of efficiently washing an object without developing defects. SOLUTION: The ultrasonic wave oscillation apparatus comprises a plurality of PLL circuits 51A, 51B for outputting respectively different high frequency signals, a selective switch 49 for selecting one or a plurality of high frequency signals from a plurality of the high frequency signals and a high frequency oscillator 31 for vibrating a vibrator based on the selected high frequency signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic oscillation device and an ultrasonic oscillation method for causing a vibrator to vibrate at a high frequency.

[0002]

2. Description of the Related Art For example, in a process of manufacturing a liquid crystal display device or a semiconductor device, there is a process that requires cleaning an object to be cleaned such as a glass substrate or a semiconductor wafer with high cleanliness. As a method of cleaning the object to be cleaned, there are a dip method in which a plurality of objects to be cleaned are immersed in a cleaning liquid and a single-wafer method in which the cleaning liquid is sprayed toward the object to be cleaned to wash one by one. In addition to obtaining high cleanliness, a single-wafer method which is advantageous in terms of cost is often used.

As one of the single-wafer methods, a cleaning method has been put to practical use in which ultrasonic vibration is applied to a cleaning liquid sprayed on a cleaning object, and the vibration action effectively removes particles from the cleaning object. ing.

Conventionally, the vibration applied to the cleaning liquid is 20 to 4
Although a frequency of about 00 kHz was generally used, in the field of precision cleaning of glass substrates, semiconductor wafers, and the like, 600 to 30 kHz was used.
A frequency of about 00 kHz is used.

The ultrasonic cleaning device has a high-frequency oscillator for outputting a high-frequency signal for generating a sound wave of the above-described frequency, and the vibrator is driven by the high-frequency signal output from the high-frequency oscillator. ing. Then, the vibration of the vibrator is applied to the cleaning liquid, and the object to be cleaned is ultrasonically cleaned.

[0006]

By the way, in recent precision cleaning, a pattern formed on a substrate to be cleaned of a glass substrate or a semiconductor wafer has been subjected to ultrasonic waves applied to the cleaning liquid in accordance with the miniaturization of the pattern and the like. Have a problem of being damaged.

As a countermeasure for reducing damage to wirings and the like, it is conceivable to reduce the oscillation output. However, if the oscillation output is reduced, the cleaning effect is also reduced, which may not be practical.

An object of the present invention is to provide an ultrasonic oscillation device and an ultrasonic oscillation method capable of reducing damage to an object to be cleaned without lowering the cleaning effect.

[0009]

According to a first aspect of the present invention, there are provided a plurality of high frequency oscillating means for outputting different high frequency signals, and a selecting means for selecting one or a plurality of high frequency signals from the plurality of high frequency signals. An ultrasonic oscillator that includes a high-frequency oscillator that vibrates the vibrator according to the selected high-frequency signal.

The ultrasonic oscillator according to claim 1, wherein said plurality of high-frequency oscillators are a plurality of modulators for modulating a signal of a predetermined frequency into high-frequency signals of different frequencies. It is in.

According to a third aspect of the present invention, there is provided the control device according to the first or second aspect, further comprising control means for controlling a modulation speed when the plurality of high-frequency signals are selected by the selection means. In the sonic oscillator.

According to a fourth aspect of the present invention, the amplitude width of the high-frequency signals output from the plurality of high-frequency oscillators is within a range from a resonance frequency of the vibrator to an anti-resonance frequency. Alternatively, an ultrasonic oscillation device according to claim 2 is provided.

According to a fifth aspect of the present invention, there is provided the ultrasonic oscillation apparatus according to the third aspect, wherein a modulation width of the plurality of high-frequency signals is 10 kHz or more, and a modulation speed controlled by the control means is 5 kHz or more. In the device.

According to a sixth aspect of the present invention, there is provided an ultrasonic oscillation method for generating a high frequency signal for vibrating a vibrator, wherein the frequency of the high frequency signal and the rate of change of the frequency are modulated. There is a sound wave oscillation method.

According to the present invention, by selecting a plurality of high frequency signals modulated in advance to a predetermined frequency and changing the frequency of the ultrasonic vibration applied to the cleaning liquid, the cleaning target can be cleaned without deteriorating the cleaning effect. Damage to an object can be reduced, and the frequency of a high-frequency signal can be switched at a high speed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The ultrasonic oscillator of the present invention shown in FIGS. 1 and 2 has a high-frequency oscillator 31, and the high-frequency oscillator 31 is connected to the high-frequency cleaner 10 via a matching circuit 27.

As shown in FIG.
Has a body 11. The main body 11 has an upper member 13 having a concave portion 12 with an open upper surface formed along the longitudinal direction, and a lower member fixed to the lower surface of the upper member 13 in a liquid-tight manner via a first seal member 14. The member 15 forms an elongated prism.

A fitting hole 16 is formed in the center of the lower wall of the upper member 13 in the width direction along the longitudinal direction. The fitting hole 16 is formed in the center of the upper surface of the lower member 15 in the width direction. A convex portion 17 to be fitted is formed.

A space 18 having one end opened to the upper surface and the other end opened to the lower surface is formed along the longitudinal direction at the center of the lower member 15 in the width direction where the projection 17 is formed. . The cross-sectional shape of the space portion 18 is tapered such that the width decreases from one end (upper end) to the other end (lower end), and the lower end opening has a narrower nozzle opening than the upper end. 19 is formed. The cleaning liquid is supplied to the space 18 from a pair of supply paths 20 formed in the lower member 15.

The open upper end of the space 18 is closed in a liquid-tight manner by a vibrating plate 21 formed in a rectangular plate shape by using tantalum, titanium or their alloys, quartz, sapphire, or the like. That is, the diaphragm 21 is joined to the inner bottom surface of the concave portion 12 of the upper member 13 through the frame-shaped second seal member 22 having a predetermined thickness at the lower peripheral portion.

A frame-like holding plate 23 is joined to the upper surface of the vibration plate 21 and is fixed to the upper member 13 by screws 20a. Thereby, the upper end opening of the space 18 is liquid-tightly closed.

A central portion in the width direction of the upper surface of the diaphragm 21;
That is, the vibrator 24 is attached to a portion corresponding to the space 18 along the longitudinal direction of the diaphragm 21. One end of a core wire of a first coaxial cable 25a having an impedance of 50Ω is electrically connected to the vibrator 24, for example. A first socket 26a is provided at the other end of the first coaxial cable 25a, and the first socket 26a is provided at one end of the matching circuit unit 27.
Is removably connected to the port 27a. In addition, the covered wire of the first coaxial cable 25a is grounded.

The other end of the matching circuit section 27 has a second
A second socket 27b provided at one end of a second coaxial cable 25b is detachably connected to the second port 27b. The other end of the second coaxial cable 25b is connected to the high frequency oscillator 31. This high-frequency oscillator 31 has a frequency synthesizer 32 as shown in FIG. This frequency synthesizer 3
2 outputs a waveform of a predetermined frequency, and the frequency is converted and controlled by the CPU 33 as a control unit.

A waveform of a predetermined frequency output from the frequency synthesizer 32 is amplified by a high-frequency power amplifier 34, and a CM coupler (pass-through power meter) for monitoring the voltage and current of the second coaxial cable 25b. The output is monitored at 35) and output to the matching circuit 27.

FIG. 4 shows a detailed configuration of the high-frequency oscillator 31. That is, after the noise is removed by the filter 42 from the power supply 41, the AC 100 V is supplied through the fuse 43, the power switch 44 and the breaker 45.
Is input to a rectifier 46 for full-wave rectification.

The signal subjected to full-wave rectification by the rectifier 46 is input to an electrolytic capacitor 47. This electrolytic capacitor 47
Is provided with a first switch 48. The first switch 48 is automatically switched between the continuous side and the pulse side by the CPU 33.
When switching to the pulse side, the signal subjected to full-wave rectification passes through the electrolytic capacitor 47, so that it becomes a pulse waveform and is input to the power amplifier 34. When switching to the continuous side, the signal is converted into a continuous waveform by the electrolytic capacitor 47 and The signal is input to the amplifier 34.

The power amplifier 34 has a volume 34
a, which are connected to each other and generate high-frequency components. In this embodiment, the first PLL circuit 51A and the second
PLL circuit 51B is connected via a selection switch 49 that is switched and controlled by the CPU 33.

The first PLL circuit 51A is connected to a second switch 52a, and the second PLL circuit 51B is connected to a third switch 52b. The second and third switches 52a and 52b are for setting the oscillation frequency of the high-frequency signal output from the first and second PLL circuits 51A and 51B to the power amplifier 34. In this embodiment, The oscillation frequency output from the first PLL circuit 51A is 1600 kHz, and the second PLL circuit 51B
Is set to 1590 kHz.

The selection switch 49 is controlled to be switched by the CPU 33. The selection switch 49 is switched, and the signal thereof is input to the first PLL circuit 51A or the second PLL circuit 51B. And the first PLL circuit 51A or the second
1600 kHz or 159 kHz from the PLL circuit 51B of
A high-frequency signal of 0 kHz is immediately output to the power amplifier 34. Selection switch 49 at this time
Is the frequency switching speed, that is, the modulation speed. As confirmed in an experiment described later, as the modulation speed increases, the number of defects (cracks) generated in the object to be cleaned decreases.

The CPU 33 connected to each of the PLL circuits 51A and 51B is provided with a fourth switch 53 for controlling the oscillation time and oscillation interval (duty ratio) of the high-frequency signal output from the power amplifier 34. . The duty ratio of the high-frequency signal can be controlled by the fourth switch 53.

That is, when a continuous wave is output from the power amplifier 34, if the duty ratio set by the fourth switch 53 is 0, a continuous wave is obtained. If the duty ratio is set to a predetermined value, As shown in FIG. 5F, a burst wave obtained by dividing a continuous wave at a predetermined period can be obtained. Further, when a pulse wave is output from the power amplifier 34, if the duty ratio is changed by the fourth switch 53, the power level of the pulse wave can be adjusted.

The high frequency signal from the power amplifier 34 is output through a VSWR circuit 54, and the traveling wave and the reflected wave of the high frequency signal are detected by the VSWR detector 54. The detection signal from the VSWR detector 54 is processed by a calculation circuit 55 and fed back to the power amplifier 34 and the CPU 33. The power amplifier 34 corrects the intensity of the high-frequency signal oscillated from the power amplifier 34 based on the setting of the volume 34a by the signal from the arithmetic circuit 55.

Further, a low-frequency oscillation circuit 57 is connected to each of the PLL circuits 51A and 51B via fifth and sixth switches 56a and 56b, respectively. When either the fifth switch 56a or the sixth switch 56b is selectively turned on, a signal of a predetermined frequency generated by the low frequency oscillation circuit 57 by the potentiometer 58 is transmitted to the first or second PLL circuit. 51A and 51B,
The frequency is modulated to a high-frequency signal of 1600 kHz or 1590 kHz.

In this embodiment, the first PLL circuit 5
1a and the second PLL circuit 51b have a modulation width of 10
Although it is set to kHz, this modulation width is within the range of the resonance frequency and the anti-resonance frequency of the vibrator 24.

Thus, even if the impedance characteristic of the vibrator 24 is partially non-uniform, the sound pressure of the high-frequency vibration output from the vibrator 24 can be made uniform.

That is, since the vibrator 24 is usually manufactured by compression-molding and sintering a powdery ceramic raw material, it is difficult for the vibrator 24 to have a constant impedance characteristic in the entire region. Therefore, even when a high-frequency signal of a predetermined frequency is uniformly supplied to the entire area of the vibrator 24, the output may not be constant.

However, by frequency-modulating the high-frequency signal supplied to the vibrator 24 in a predetermined frequency range,
Even if the impedance characteristics in the entire region of the vibrator 24 are not constant, a high-frequency signal having a frequency corresponding to the impedance characteristic can be supplied to each region. Thereby, the intensity of the ultrasonic wave output from the transducer 24 can be made substantially uniform.

As shown in FIG.
Is provided with a timer 61 and a relay circuit 62.
The timer 61 measures the oscillation time, and is provided with a reset switch 63 for resetting the measurement time. The relay circuit 62 performs various displays using a plurality of lamps 64.

The first to sixth switches 48, 48
The operations of 52a, 52b, 53, 56a, and 56b can be automatically operated by the CPU 33.

A part of the signal from the power supply 41 is
Fan 65 and CP for cooling high-frequency oscillator 31
It is designed to be input to a converter 66 for converting an AC voltage to a DC voltage to drive U33.

Next, using the above ultrasonic oscillator, FIG.
A case in which a high-frequency signal having the waveforms shown in FIGS.

First, when outputting the high frequency signal of the first waveform 71 shown in FIG. 5A, the CPU 33 turns on the power switch 44 to turn on the power.
Is set so that the waveform 71 is output. Based on the setting of the CPU 33, the first switch 48 switches to the pulse side at the initial stage of the oscillation when the oscillation operation is started, and switches to the continuous side at the same time as the end of the pulse oscillation (one-pulse oscillation in this embodiment).

As a result, at the initial stage of oscillation when the first switch 48 is switched to the pulse side, the signal that has been full-wave rectified by the rectifier 46 passes through the electrolytic capacitor 47.
From the power amplifier 34, a high frequency signal of the frequency set by the second switch 52 is pulse-oscillated.

When the pulse oscillation of the high-frequency signal ends, the first switch 48 switches to the continuous side.
The signal subjected to full-wave rectification in 6 is smoothed by an electrolytic capacitor 47 and input to the power amplifier 34.

As a result, the signal from the electrolytic capacitor 47 continuously oscillates at a lower power level than the pulse oscillation. That is, the first waveform 71 is pulse oscillation at the beginning of oscillation, and is continuous oscillation thereafter.

When such a waveform of the first high-frequency signal is input to the vibrator 24, the object to be cleaned can be cleaned at first with high-power pulse oscillation, and thereafter cleaned with low-power continuous oscillation for a predetermined time. Can be.

For this reason, the first pulse oscillation makes it relatively hard to adhere to the object to be cleaned and hardly falls off, and particles having a large particle size can be removed.
Next, by continuously performing continuous oscillation for a predetermined time, it is possible to reliably remove particles that cannot be removed in a short time, such as particles that adhere to an object to be cleaned in a normal state and particles having a relatively small particle diameter. it can.

When outputting the high-frequency signal waveform of the second waveform 72 shown in FIG. 5B, the CPU 33 is set to a state where the second waveform is output. When the oscillating operation is started based on the setting of the CPU 33, first, the first switch 48 is switched to the continuous side until a predetermined time elapses after the oscillating operation starts.

As a result, the signal that has been full-wave rectified by the rectifier 46 continuously oscillates. When the continuous oscillation is performed for a predetermined time, the first switch 48 is switched to the pulse side, so that the signal rectified by the full-wave rectifier 46 passes through the electrolytic capacitor 47 and oscillates at a predetermined frequency.

Therefore, according to such an oscillation waveform, most particles adhering to the object to be cleaned are removed by continuous oscillation for a predetermined time, but particles not removed by continuous oscillation are removed by the last pulse oscillation. Therefore, in this case, as in the case of the first waveform, a sufficient cleaning effect can be obtained even if the state and size of the particles adhered to the object to be cleaned are not constant.

When outputting the high-frequency signal waveform of the third waveform 73 shown in FIG. 5C, the CPU 33 is set to output the third waveform 73. CPU33
When oscillation is started based on the setting of the first switch 4
8 is switched from the continuous side to the pulse side at predetermined time intervals by a control signal from the CPU 33.

Thus, the waveform 7 of the third high-frequency signal
In No. 3, since pulse oscillation and continuous oscillation are repeated, if a large amount of particles that are relatively difficult to remove adhere to the object to be cleaned, if this third waveform 73 is applied, only pulse oscillation will be performed. The cleaning effect can be enhanced without giving too much impact to the object to be cleaned, as compared with the case where the object to be cleaned is washed.

The fourth waveform 74 shown in FIG. 5D is a continuous wave, and when the CPU 33 is set to output this waveform, the first switch 48 is switched to the continuous side. As a result, the signal that has been full-wave rectified by the rectifier 46 is smoothed by the electrolytic capacitor 47 and
, Continuous oscillation is performed at a predetermined frequency.

When a continuous wave having the fourth waveform 74 is oscillated, the duty ratio is set to 0 by the fourth switch 53.
By setting to a predetermined value from, as shown in FIG.
A burst wave in which a continuous wave is divided at a predetermined period can be obtained. This cycle can be arbitrarily set by the duty ratio. The waveform in FIG. 5F is referred to as a sixth waveform 76.

The fifth waveform 75 shown in FIG. 5E is a pulse wave, and when the CPU 33 is set to output this waveform, the first switch 48 is switched to the pulse side. Thus, the signal that has been full-wave rectified by the rectifier 46 passes through the electrolytic capacitor 47 and is input to the power amplifier 34, so that pulse oscillation is performed at a predetermined frequency.

When a pulse wave having the fifth waveform 75 is oscillated, the output level of the pulse wave can be adjusted by setting the duty ratio to a predetermined value by the fourth switch 53. The object to be cleaned can be washed at an output level suitable for the state of contamination of the object.

As described above, since the switching of the first switch 48 is controlled by the CPU 33, an oscillation waveform combining a pulse wave and a continuous wave can be obtained.
By setting the oscillation waveform in accordance with the type and size of the particles attached to the object to be cleaned, the cleaning effect can be improved.

In addition, not only the first to third waveforms 71 to 73 in which the pulse wave and the continuous wave are combined, but also the fourth waveform 74 of the continuous wave and the fifth waveform 75 of the pulse wave alone are oscillated. Therefore, even when the first to third waveforms cannot cope, it is possible to cope with the case.

Further, when the duty ratio is set by the fourth switch 53, when a continuous wave is oscillated,
A burst wave can be obtained from a continuous wave, and when a pulse wave is oscillated, the output level of the pulse wave can be changed, so that an oscillation waveform corresponding to various cleaning conditions can be set. it can.

When oscillating a high-frequency signal with the first to sixth waveforms, the high-frequency signal oscillated and output from the power amplifier 34 can be modulated. That is, in the case of this embodiment, the fifth switch 56a and the sixth switch 56b are turned on by the CPU 33, and the selection switch 49 is switched at a predetermined speed.

The selection switch 49 is connected to the first PLL circuit 51
When switched to the A side, the first PLL circuit 51A
Is output from the VSWR detector 54 through the power amplifier 34,
When the selection switch 49 is switched to the second PLL circuit 51B, the 1590 kHz high-frequency signal generated by the second PLL circuit 51B is output from the VSWR detector 54 through the power amplifier 34.

That is, a high-frequency signal having a frequency of 1600 kHz and a high-frequency signal having a frequency of 1590 kHz, that is, two high-frequency signals having a modulation width of 10 kHz can be output at a modulation speed corresponding to the switching speed of the changeover switch 49. The changeover of the changeover switch 49 is performed by the CPU 3
3, it is possible to perform the switching at a high speed, and thereby the frequency can be switched continuously, so that the damage to the object to be cleaned can be reduced.

6 and 7, when the modulation width and the modulation speed given to the cleaning liquid are changed, defects such as cracks generated in the semiconductor wafer and PSL applied to the semiconductor wafer are changed.
The experimental result of this invention which measured the removal rate of (polystyrene type latex) is shown.

The experimental conditions were as follows: the semiconductor wafer diameter was fixed at 200 mm, and the MHz output was fixed at 60 W. The cleaning liquid is pure water.

FIG. 6 shows a case where the modulation speed is fixed at 10 kHz and the modulation width is gradually increased from 1590 kHz. As shown by a line A in FIG. 6, when the modulation width is 0, that is, 1590 kHz harmonics are obtained. When the semiconductor wafer was cleaned by applying it to the cleaning liquid without modulating the signal, 527 defects such as cracks were measured on the semiconductor wafer. If the modulation width is 1 kHz, the number of defects becomes 17 and 10
When the modulation width became equal to or more than kHz, the number of defects was reduced to 2 to 7.

In the figure, line B is the removal rate of PSL applied to the semiconductor wafer, and this removal rate was 99.4% or more without being largely affected by the modulation width.

As is clear from the experiment shown in FIG. 6, when the modulation speed of the high-frequency signal applied to the cleaning liquid is fixed at 10 kHz and the frequency is modulated, the number of defects generated in the semiconductor wafer can be greatly reduced. In particular, the modulation width is 1
It was confirmed that when the frequency was set to 0 kHz or more, the number of defects was significantly reduced. In addition, by fixing the MHz output at 60 W, the number of defects generated in the semiconductor wafer could be reduced without lowering the cleaning effect.

FIG. 7 shows a case where the modulation width is fixed at 10 kHz and the modulation speed is gradually increased from 0 kHz. When the modulation speed is 0 as shown by a line C in FIG. Defects occurred, but the number of defects was drastically reduced by gradually increasing the modulation speed.
Five and 52 kHz were measured at 2.5 kHz, and 0 or 2 at 5 kHz or more.

In the figure, the line D is the PSL removal rate.
This rejection was 99.4% or more with little effect on the modulation speed.

As is clear from the experiment shown in FIG. 7, by modulating the modulation speed while fixing the modulation width of the high-frequency signal applied to the cleaning liquid to 10 kHz, the number of defects generated in the semiconductor wafer can be significantly reduced. It was confirmed that when the modulation speed was set to 5 kHz or more, the number of defects was significantly reduced. In addition, by fixing the MHz output at 60 W, the number of defects generated in the semiconductor wafer could be reduced without lowering the cleaning effect.

As is clear from these experiments, while modulating the frequency of the high-frequency signal applied to the cleaning solution,
It has been confirmed that by modulating the rate of change of the frequency, a high cleaning effect can be obtained with almost no defects in the semiconductor wafer. In particular, it has been found that the effect becomes remarkable when the modulation width is 10 kHz or more and the modulation speed is 5 kHz or more.

The reason why such a cleaning effect can be obtained is that, when the frequency is modulated, the semiconductor wafer is cleaned by vibration of an indefinite period, so that the semiconductor wafer resonates with the frequency of the high-frequency signal and defects are generated. This can be prevented from occurring.

Further, the frequency modulation is performed by the first and second PLs.
Since the switching can be performed at a high speed by switching the L circuits 51A and 51B, the switching of the frequency becomes continuous. Therefore, it is considered that the impact given to the semiconductor wafer at the time of switching the frequency can be reduced and the occurrence of defects can be prevented.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above embodiment, the first and second PLL circuits convert a high-frequency signal to 15
The modulation was performed at 90 kHz and 1600 kHz, but by providing three or more PLL circuits, 1590 kHz and 160 kHz were obtained.
The signal may be modulated and output to a high-frequency signal other than 0 kHz.

In the above-described embodiment, the case where the present invention is applied to a single-wafer method in which objects to be cleaned such as semiconductor wafers are cleaned one by one has been described. The present invention can also be applied to a batch system in which cleaning is performed at the same time.

[0077]

As described above, according to the present invention, a plurality of high frequency signals modulated in advance to a predetermined frequency can be selected, and the frequency of the high frequency signal applied to the cleaning liquid can be changed.

Therefore, it is possible to reduce the damage to the object to be cleaned without deteriorating the cleaning effect, and it is possible to switch the frequency of the high-frequency signal at a high speed.

Further, when the frequency of the high-frequency signal is switched and the switching speed of the frequency is modulated, defects occurring in the object to be cleaned can be further reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an ultrasonic oscillator according to an embodiment of the present invention.

FIG. 2 is a sectional view of an ultrasonic cleaning machine.

FIG. 3 is a schematic diagram of a high-frequency oscillator.

FIG. 4 is a circuit diagram of a high-frequency oscillator.

FIG. 5 is an explanatory diagram of a waveform obtained by a high-frequency oscillator.

FIG. 6 is a graph in which the number of defects generated on a semiconductor wafer and the removal rate of dirt are measured when the modulation speed is kept constant and the modulation width is changed.

FIG. 7 is a graph in which the number of defects generated in a semiconductor wafer and the removal rate of dirt are measured when the modulation width is fixed and the modulation speed is changed.

[Explanation of symbols]

 31 high frequency oscillator 33 CPU (control unit) 48 first switch 49 selection switch 51A first PLL circuit 52B second PLL circuit 52a second switch 52b third switch 53 third Fourth switch 56a: Fifth switch 56b: Sixth switch

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Osamu Sato 1000-1, Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Shibaura Mechatronics Co., Ltd. Yokohama Office Inside the Toshiba Production Technology Center Co., Ltd. (72) Inventor Koichi Higuchi 33 Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 3B201 AA02 AA03 AB53 BB02 BB83 BB92 5D107 AA02 AA06 AA09 AA14 BB11 CC01 CD04 CD05

Claims (6)

[Claims] An oscillator comprising: a plurality of high-frequency oscillators each outputting a different high-frequency signal; and a selector for selecting one or a plurality of high-frequency signals from the plurality of high-frequency signals. An ultrasonic oscillator comprising a high-frequency oscillator that vibrates the ultrasonic wave. 2. The ultrasonic oscillator according to claim 1, wherein said plurality of high-frequency oscillators are a plurality of modulators for modulating a signal of a predetermined frequency into high-frequency signals of different frequencies. 3. The ultrasonic oscillator according to claim 1, further comprising control means for controlling a modulation speed when the plurality of high-frequency signals are selected by the selection means. 4. The apparatus according to claim 1, wherein an amplitude width of a high-frequency signal output from the plurality of high-frequency oscillators is within a range from a resonance frequency of the vibrator to an anti-resonance frequency.
Alternatively, the ultrasonic oscillator according to claim 2. 5. The modulation width of the plurality of high-frequency signals is 10k.
4. The ultrasonic oscillator according to claim 3, wherein the modulation speed controlled by the control means is 5 kHz or more at Hz or more. 6. An ultrasonic oscillation method for generating a high-frequency signal for vibrating a vibrator, wherein the frequency of the high-frequency signal and a rate of change of the frequency are modulated.