JP2000114220A - Device and method for spin processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spin processing device, capable of surely measuring the intensity of ultrasonic vibrations applied to a processing liquid. SOLUTION: A spin-processing device for processing a semiconductor wafer U by a processing liquid, to which ultrasonic vibrations are applied has a rotary table 12 for holding and rotating the semiconductor wafer U; an ultrasonic nozzle 31 driven along the radial direction of the semiconductor wafer U held by the rotary table 12, and applying ultrasonic vibration to a processing liquid supplied thereinto and injecting it, and a sound pressure detecting device 55 arranged outside the peripheral end in the radial direction of the semiconductor wafer on a direct extension in the direction, in which the ultrasonic nozzle 31 is driven and for detecting the sound pressure of the ultrasonic waves applied to a processing liquid by the ultrasonic nozzle 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spin processing apparatus for processing an object to be processed with a processing liquid to which ultrasonic vibration has been applied.

[0002]

2. Description of the Related Art For example, in a liquid crystal manufacturing apparatus or a semiconductor manufacturing apparatus, there is a process required to clean an object to be processed such as a glass substrate for a liquid crystal or a semiconductor wafer with high cleanliness. 2. Description of the Related Art A spin processing apparatus that performs processing while rotating an object to be processed is used.

[0003] In a spin processing apparatus, when the object to be processed is cleaned with a high degree of cleanliness, ultrasonic vibration is applied to a processing liquid for cleaning the object to be processed. When the object to be processed is cleaned with the processing liquid to which the ultrasonic vibration is applied, fine particles and the like adhering to the object to be processed can be efficiently removed, so that the cleaning effect can be enhanced.

In order to apply ultrasonic vibration to a processing liquid,
An ultrasonic nozzle body having a vibration plate provided therein is used. That is, the ultrasonic nozzle body has a space portion to which the processing liquid is supplied, and in this space portion, the diaphragm is provided so as to expose the inner surface.

An ultrasonic vibrator is adhered to the outer surface of the vibrating plate. An ultrasonic oscillator is electrically connected to the ultrasonic vibrator, and the ultrasonic oscillator vibrates by being supplied with power from the ultrasonic oscillator. Accordingly, the vibration plate vibrates ultrasonically together with the ultrasonic vibrator, so that the vibration plate applies ultrasonic vibration to the processing liquid supplied to the space.

By the way, in such a processing apparatus,
One of the factors which influence the quality of the processing effect of the processing object is the intensity of the ultrasonic vibration applied to the processing liquid. The intensity of the ultrasonic vibration applied to the processing liquid varies depending on various causes.

For example, an ultrasonic vibrator is attached to a vibration plate of an ultrasonic nozzle body with an adhesive, but it is inevitable that the state of adhesion is deteriorated with use. As a result, the transmission efficiency of the vibration from the ultrasonic vibrator to the diaphragm is reduced, so that the intensity of the ultrasonic vibration applied to the processing liquid is also reduced, and the cleaning effect is also reduced. Therefore, the intensity of the ultrasonic vibration applied to the processing liquid by the ultrasonic nozzle body must be measured and managed so as to obtain a reliable cleaning effect.

[0008]

As described above, in a spin processing apparatus for processing an object to be processed with a processing liquid to which ultrasonic vibration has been applied, is the processing liquid subjected to ultrasonic vibration of a predetermined intensity? Although it is necessary to determine whether or not it is, such a thing has not been performed in the conventional spin processing apparatus.

It is an object of the present invention to provide a spin processing apparatus capable of efficiently detecting whether or not ultrasonic vibration of a predetermined intensity is applied to a processing liquid by an ultrasonic nozzle body.

[0010]

According to a first aspect of the present invention, there is provided a spin processing apparatus for processing an object to be processed with a processing liquid to which ultrasonic vibrations are applied. A table, an ultrasonic nozzle body that is driven along the radial direction of the object to be processed held by the rotary table, applies ultrasonic vibration to the processing liquid supplied therein, and jets the processing liquid; A sound pressure detecting means which is arranged at a standby position outside the radial periphery of the object to be processed on an extension of the body driving direction and detects the sound pressure of ultrasonic waves applied to the processing liquid by the ultrasonic nozzle body. And characterized in that:

According to a second aspect of the present invention, in the first aspect of the present invention, the ultrasonic nozzle body includes an arm body that is driven to swing in parallel with a processing surface of the processing object held on the rotary table. An axis is inclined at a predetermined angle with respect to the surface of the object to be processed.

According to a third aspect of the present invention, there is provided a spin processing method for processing an object to be processed by a processing liquid to which ultrasonic vibration is applied, wherein the step of holding and rotating the object to be processed, A step of driving an ultrasonic nozzle body that applies and ejects ultrasonic vibrations along a radial direction of the object to be processed, which is held on the rotary table and driven to rotate, and on an extension of a driving direction of the ultrasonic nozzle body. A step of detecting the sound pressure of the ultrasonic wave applied to the processing liquid by the ultrasonic nozzle at a standby position outside the radial periphery of the object to be processed.

According to the first and third aspects of the present invention, the intensity of the ultrasonic vibration applied to the processing liquid ejected from the ultrasonic nozzle body by the sound pressure detecting means can be measured.
Moreover, since the sound pressure detecting means is provided at the standby position on the extension of the moving direction of the ultrasonic nozzle body, the ultrasonic vibration is generated when the ultrasonic nozzle body is retracted in order to attach and detach the object to be processed to and from the rotary table. Can be measured.

According to the second aspect of the present invention, since the ultrasonic nozzle body is inclined with respect to the processing surface of the object to be processed, the reflected wave from the surface to be processed is different from the traveling wave from the ultrasonic nozzle body. It is possible to prevent the detection accuracy from being lowered due to interference.

[0015]

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

FIG. 1 shows a spin processing device, which has a cup body 1. The cup body 1 includes a lower cup 3 provided on an installation plate 2 and an upper cup 4 provided on the upper side of the lower cup 3 so as to be vertically movable by a vertical driving mechanism (not shown).

The center of the bottom wall of the lower cup 3 and the mounting plate 2
The upper cup 4 is formed with a through hole 5 penetrating therethrough, and the peripheral wall 3a of the lower cup 3 is slidably inserted into the double peripheral wall 4a of the upper cup 4 to form a labyrinth structure by these peripheral walls. ing.

The upper surface of the upper cup 4 is open, and when the upper cup 4 is driven in a downward direction, as an object to be processed which has been subjected to a process such as washing in the cup body 1 as described later. For example, it is possible to take out a semiconductor wafer U or supply an unprocessed semiconductor wafer U.

One end of a plurality of discharge pipes 6 is connected to the bottom wall of the lower cup 3 at predetermined intervals in the circumferential direction, and the other end is connected to a suction pump (not shown). Thereby, the processing liquid dropped onto the inner bottom of the cup body 1 by processing or drying the semiconductor wafer U can be discharged.

A base 7 is arranged on the lower surface side of the cup body 1. A mounting hole 8 is formed in the base 7 at a position corresponding to the through hole 5 of the cup body 1, and the mounting hole 8 has a stator 9a of a pulse control motor 9 constituting driving means. Is fitted and fixed.

The stator 9a has a cylindrical shape, and a cylindrical rotor 9b is rotatably fitted therein. A cylindrical connecting body 11 is provided on the upper end surface of the rotor 9b.
Are fixed integrally by joining the lower end surfaces. A flange 11a having a diameter larger than the inner diameter of the stator 9a is formed on the lower end surface of the connecting body 11. The flange 11a is slidably joined to the upper end surface of the stator 9a, thereby restricting the rotor 9b from falling off the stator 9a without preventing rotation of the rotor 9b. .

The connecting body 11 is provided with the through hole 5 of the cup body 1.
And a disk-shaped rotary table 12 is attached and fixed to the upper end surface thereof. This rotary table 12
A plurality of holding members 13 are rotatably provided at predetermined intervals in the circumferential direction at the peripheral portion of the upper surface of the holding member 13, in this embodiment, at 90 ° intervals. On the upper surface of the holding member 13, a conical support pin 14 is protruded at the center, and a reverse taper is provided at an eccentric position.
A lock pin 15 in the shape of a protrusion projects.

The semiconductor wafer U supplied into the cup body 1 by a robot (not shown) is supported on the support pins 14 on the lower surface of the peripheral portion. In this state, the holding member 13
Rotates and the lock pin 15 rotates eccentrically, thereby engaging with the outer peripheral surface of the semiconductor wafer U and holding the semiconductor wafer U.

An urging spring 16 is provided on the outer peripheral surface of the connecting body 11.
Is provided. The urging spring 16 urges a parent gear (not shown) rotatably provided on the lower surface of the rotary table 12 with respect to the rotary table 12 in a predetermined rotation direction. A plurality of child gears (not shown) are meshed with the parent gear, and each child gear is fitted to an end of the holding member 13 protruding from the lower surface of the rotary table 12. As a result, the holding pin 13 of the semiconductor wafer U
Are urged in the locking direction to be engaged with the outer peripheral surface of.

The semiconductor wafer U by the lock pin 15
Is released by the release mechanism 17.
The release mechanism 17 includes a release cylinder 18, an arm 19 driven by the release cylinder 18, and a release pin 21 provided at an upper end of the arm 19.

When the release cylinder 18 is actuated and the release pin 21 prevents the rotation of the master gear, the rotary table 12 is driven by the pulse control motor 9 to rotate the urging spring 1.
6, the holding member 13 is rotated, and the lock state of the semiconductor wafer U by the lock pin 15 is released.

A through hole 1 is provided at the center of the rotary table 12.
2a is formed. A hollow fixed shaft 22 is passed through the rotor 9b, and the upper end of the fixed shaft 22 projects into the through hole 12a of the rotary table 12. A nozzle head 23 is fitted on the upper end of the fixed shaft 22.
The nozzle head 23 has a plurality of lower cleaning nozzles 24 for injecting a processing liquid toward the lower surface of the semiconductor wafer U held on the rotary table 12 and a gas nozzle for injecting a drying gas such as nitrogen (FIG. (Not shown).

The lower end of the fixed shaft 22 has a pulse control mode.
It is fitted and fixed in a support hole 25 a of a support 25 arranged on the lower surface side of the table 9. The support 25 is provided with a brake xylider 26. A brake shaft 27 is provided on the drive shaft of the brake cylinder 26.
When the brake cylinder 26 operates, the kish 27 comes into pressure contact with a brake disk 28 provided on the lower end surface of the pulse control motor 9. Thereby, the rotor 9b of the pulse control motor 9 is prevented from rotating.

That is, the rotary table 12 is moved to the biasing spring 16
Is rotated a predetermined angle against the urging force of the lock pin 1
When the driving force of the pulse control motor 9 is lost due to a power failure or the like while the locked state of the semiconductor wafer U by the lock table 5 is released, the rotary table 12 can be biased by the biasing spring 16.
It prevents rotation by the restoring force. Thereby,
Even if a power outage occurs, the semiconductor wafer U
Can be reliably maintained.

The upper surface of the rotary table 12 is covered with a turbulence prevention cover 29. This turbulence prevention cover
An opening 29 for exposing the nozzle head 23 is provided at 29.
a and an opening 29b for exposing the holding member 13 are formed. The turbulence prevention cover 29 is spaced apart from the lower surface of the semiconductor wafer U supported by the support pins 14 at a predetermined interval. Is prevented.

The upper surface to be processed of the semiconductor wafer U held in the cup body 1 is subjected to a cleaning process using a processing liquid ejected from the ultrasonic nozzle body 31. The ultrasonic nozzle body 31 has a main body 33 in which a space 32 is formed as shown in FIG. The main body 33 has a supply port 3 on a side surface for supplying a processing liquid to the space 32.
A nozzle hole 35 for ejecting the processing liquid supplied to the space 32 is formed on the lower end surface.

Further, the main body 33 is provided with a vibration plate 36 in a liquid-tight manner with the lower surface facing the space 32.
An ultrasonic vibrator 37 is attached to the upper surface of the vibrating plate 36 by means such as bonding. This ultrasonic vibrator 37
Is electrically connected to an ultrasonic oscillator (not shown) and is supplied with power. Thereby, the ultrasonic vibrator 37 ultrasonically vibrates and the vibration plate 36 is interlocked with the ultrasonic vibrator 37, so that the ultrasonic vibration can be applied to the processing liquid supplied to the space 32 of the main body 33.

As shown in FIG. 1, the ultrasonic nozzle body 31 is formed at the tip of the horizontal part 43 of an arm 41 having a substantially inverted L-shape formed by a vertical part 42 and a horizontal part 43. The supply port 34 formed in the main body 33 at a portion which is inclined at a predetermined angle? It is installed in the position.

The supply port 34 of the main body 33 is connected to one end of a supply pipe 44 for supplying a processing liquid. The supply pipe 44 passes through the hollow vertical portion 42 and the horizontal portion 43 of the arm 41 and communicates with a processing liquid supply source (not shown).

An upper end of the main body 33 is connected to one end of a wiring tube 45 through which a lead wire (not shown) for supplying power to the ultrasonic vibrator 37 is passed. This wiring tube 45
As in the case of the supply pipe 44, is passed through the interior of the vertical portion 42 from the horizontal portion 43 and is connected to an ultrasonic oscillator (not shown).

Further, the main body 3 of the ultrasonic nozzle body 31
The outer peripheral surface of 3 is covered with a cover body 46. The cover body 46 surrounds the periphery of the nozzle hole 35 at the tip of the upper ultrasonic nozzle body 31. Thereby, the mist generated when the processing liquid ejected from the upper ultrasonic nozzle body 31 collides with the semiconductor wafer U collides with the inner peripheral surface of the cover body 46 and is prevented from scattering around. It has become.

The lower end of the cover body 46 is parallel to the upper surface of the semiconductor wafer U so that the upper ultrasonic nozzle 3
1 is formed on an inclined surface corresponding to the inclination angle θ. This prevents a gap between the upper surface of the semiconductor wafer U and the lower end surface of the cover body 46 from increasing.

The vertical portion 42 of the arm body 41 is
Through the insertion hole 47 formed in the arm 7 and the arm 4
1 is connected to a rotor (not shown) of a first drive source 48 composed of a hollow shaft motor which drives the rocker 1 within a predetermined angle range. The first drive source 48 is attached to a movable plate 49. The movable plate 49 is slidably provided in a vertical direction on a fixed plate 51 suspended from the base 7 by a linear guide (not shown).

The fixed plate 51 is provided with a second drive source 52. A ball screw (not shown) is connected to the drive shaft 52a of the second drive source 52, and the ball screw is screwed to a nut (not shown) provided on the movable plate 49. Therefore, when the second drive source 52 is operated to rotate the ball screw, the movable plate 49 is driven in the vertical direction indicated by the arrow.

That is, the ultrasonic nozzle body 31 is
Above the semiconductor wafer U held in the cup body 1 by the driving source 48, and is oscillated along the radial direction of the semiconductor wafer U, and is driven vertically by the second driving source 52, It is held at a predetermined height position.

As shown in FIGS. 3 and 4, the outer side of the cup body 1 is located outside the radial periphery of the semiconductor wafer U on the extension line in the swinging direction of the ultrasonic nozzle body 31. A sound pressure detector 55 for detecting the intensity of the ultrasonic vibration applied to the processing liquid by the ultrasonic nozzle body 31
Is provided. The sound pressure detector 55 is an ultrasonic nozzle 3
1 is disposed opposite to a position where the semiconductor wafer U stands by when the semiconductor wafer U is not subjected to the cleaning process.

The sound pressure detector 55 displays a probe 56 for converting the ultrasonic vibration into a voltage by spraying the processing liquid to which the ultrasonic vibration is applied, and a voltage value detected by the probe 56. A display section 57 for issuing an alarm such as a buzzer or a lamp when the value is equal to or less than a predetermined value.

Next, a case where the semiconductor wafer U is cleaned by the processing apparatus having the above configuration will be described. First, an uncleaned semiconductor wafer U is supplied into the cup body 1,
It is supported by the support pin 14 and the lock pin 15
Then, the processing liquid is supplied to the ultrasonic nozzle body 31, and the air in the space 32 of the main body 33 is vented.

The ultrasonic nozzle body 31 is inclined at a predetermined angle to the horizontal portion 43 of the arm body 41, and the supply port 34 to which the supply pipe 44 for supplying the processing liquid is connected is positioned on the upper side in the inclination direction. Installed. Therefore, when the processing liquid fills the space 32 of the ultrasonic nozzle body 31, the air remaining in the space 32 accumulates on the supply port 34 side, which is a high position in the space 32.

The air collected on the supply port 34 side of the space 32 is easily washed away by the processing liquid supplied from the supply port 34 to the space 32 and flows out of the nozzle hole 35 together with the processing liquid. Therefore, air can be removed from the space 32 in a relatively short time and reliably.

When the air bleeding of the space 32 of the ultrasonic nozzle body 31 is completed, the rotary table 12 is driven to rotate the semiconductor wafer U, and the arm body 41 is swung so that the ultrasonic nozzle body 31 is rotated. Is positioned at the radial center of the upper surface of the semiconductor wafer U, and is then swung radially outward. At the same time, power is supplied to the ultrasonic vibrator 37 to ultrasonically vibrate the diaphragm 36.

As a result, the processing liquid flowing through the space 32 of the ultrasonic nozzle body 31 is subjected to ultrasonic vibration and is ejected from the nozzle hole 35 toward the semiconductor wafer U. Ultrasonic cleaning.

When the processing liquid to which the ultrasonic vibration is applied collides with the upper surface of the semiconductor wafer U, a part of the processing liquid becomes a mist, and the mist tends to scatter around by the air flow accompanying the rotation of the rotary table 12. .

However, at the lower end of the main body 33 of the ultrasonic nozzle body 31, there is provided a cover body 46 for covering the outer peripheral surface thereof. Therefore, even if the processing liquid is ejected from the nozzle holes 35 of the upper ultrasonic nozzle body 31 and collides with the semiconductor wafer U, mist is generated. Most of the mist adheres to the inner peripheral surface of the cover body 46. However, since there is almost no mist scattered around, it is possible to prevent the mist from re-adhering to the washed semiconductor wafer U.

When the processing liquid to which the ultrasonic vibration is applied collides with the semiconductor wafer U, the ultrasonic vibration wave W is reflected on the surface of the semiconductor wafer U as shown by an arrow in FIG. However, since the upper ultrasonic nozzle body 31 is attached to the arm body 41 at a predetermined angle θ, the upper ultrasonic nozzle body 31 is positioned on the semiconductor wafer U in the emission direction of the traveling wave of the ultrasonic vibration wave W. Since the direction of the reflected wave to be reflected is different, the reflected wave of the ultrasonic vibration wave W is reflected by the nozzle hole 35 of the ultrasonic nozzle body 31.
From the inside.

If the ultrasonic vibration wave W reflected by the semiconductor wafer U is incident on the upper ultrasonic nozzle body 31, the reflected wave acts on the vibration plate 36 to attenuate the vibration of the vibration plate 36 or to reduce the resonance. Inducing the state, the diaphragm 36 and the ultrasonic vibrator 3
7, the reflected wave interferes with the traveling wave to reduce the intensity of the traveling wave, but the reflected wave reflected by the semiconductor wafer U is reflected in a direction different from the traveling wave. Therefore, occurrence of such inconvenience can be prevented.

The lower surface of the semiconductor wafer U can also be cleaned by jetting a processing liquid from the lower cleaning nozzle 24 toward the lower surface simultaneously with the upper surface, if necessary.

When the cleaning of the semiconductor wafer U is completed in this manner, a drying gas is supplied to the upper and lower surfaces of the semiconductor wafer U to perform a drying process, and the upper cup 4 of the cup body 1 is lowered. After that, the upper ultrasonic nozzle body 31 is retracted to the standby position facing the probe 56 of the sound pressure detector 55 outside the cup body 1. Next, when the locked state of the semiconductor wafer U by the lock pins 15 is released, the semiconductor wafer U is taken out and the uncleaned semiconductor wafer U is supplied.

During the standby time for taking out and supplying the semiconductor wafer U, the processing liquid to which the ultrasonic vibration is applied is jetted from the ultrasonic nozzle body 31 toward the probe 56, and the intensity of the ultrasonic vibration applied to the processing liquid is increased. Is measured. If the intensity is equal to or greater than a preset value, a new semiconductor wafer U is cleaned in that state, and if the intensity is equal to or less than the set value,
Since this is warned by the display unit 57, the inspection and repair of the ultrasonic nozzle body 31 are performed. This makes it possible to prevent the semiconductor wafer U from being cleaned by a processing liquid to which ultrasonic vibration having a predetermined intensity or less is applied and causing a cleaning defect.

Further, the measurement of the sound pressure intensity applied to the processing liquid can be performed on an extension of the oscillation direction of the ultrasonic nozzle body 31 and while the semiconductor wafer U is being attached to and detached from the rotary table, that is, at the time of standby. . Therefore, the measurement does not need to be performed as a separate step from the processing step of the semiconductor wafer U, and the measurement does not cause a decrease in productivity. Moreover, since the measurement can be performed before each semiconductor wafer U is subjected to the cleaning process, it is possible to reliably clean all the semiconductor wafers U with the processing liquid to which the ultrasonic vibration of the predetermined intensity is applied. .

Further, since the upper ultrasonic nozzle body 31 is attached to the arm body 41 at a predetermined angle .theta., The same as in the case of cleaning the semiconductor wafer U as shown in FIG. The direction of the reflected wave reflected by the probe 56 is different from the emission direction of the traveling wave of the ultrasonic vibration wave W as shown by a chain line in FIG.

Therefore, since the reflected wave from the probe 56 does not interfere with the traveling wave from the ultrasonic nozzle body 31 to reduce the intensity of the traveling wave, the intensity of the ultrasonic vibration wave W can be accurately determined. Can be measured.

In the above-described embodiment, a semiconductor wafer is described as an object to be processed. However, a glass substrate for liquid crystal may be used instead of the semiconductor wafer. What is necessary is just an object to be processed.

[0059]

According to the first and third aspects of the present invention, the sound pressure detector for measuring the intensity of the ultrasonic vibration applied to the processing liquid ejected from the ultrasonic nozzle body is provided by the ultrasonic nozzle body. At the standby position of the ultrasonic nozzle on the extension of the moving direction of the ultrasonic nozzle.

Therefore, the strength of the ultrasonic vibration applied to the processing liquid when the ultrasonic nozzle body is retracted to the standby position in order to attach and detach the object to be processed to and from the rotary table can be measured. It is not necessary to reduce productivity or to take extra time to perform the measurement.

According to the second aspect of the present invention, the ultrasonic nozzle body is provided so as to be inclined with respect to the processing surface of the workpiece.

Therefore, when measuring the intensity of the ultrasonic vibration, it is possible to prevent the traveling wave from the ultrasonic nozzle from interfering with the reflected wave from the sound pressure detector. Can be detected.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spin processing apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of the ultrasonic nozzle body.

FIG. 3 is a plan view showing an arrangement state of a spin processing device and a sound pressure detector.

[Explanation of symbols]

 12: rotary table 31: ultrasonic nozzle body 41: arm body 55: sound pressure detector (sound pressure detecting means) U: semiconductor wafer (workpiece)

Claims (3)

[Claims] 1. A spin processing apparatus for processing an object to be processed with a processing liquid to which ultrasonic vibration is applied, comprising: a rotary table that holds and rotates the object to be processed; and a rotating table that is held by the rotary table. An ultrasonic nozzle body that is driven along the radial direction of the processing object and applies ultrasonic vibration to the processing liquid supplied therein and ejects the processing liquid, and on an extension of the driving direction of the ultrasonic ultrasonic nozzle body, And a sound pressure detecting means for detecting a sound pressure of an ultrasonic wave applied to the processing liquid by the ultrasonic nozzle body, which is disposed at a standby position outside a radial periphery of the object to be processed. Spin processing device. 2. The ultrasonic nozzle body includes an arm body that is swingably driven in parallel with a processing surface of the processing object held on the rotary table, and has an axis line with respect to the processing surface of the processing object. 2. The spin processing device according to claim 1, wherein the spin processing device is provided at a predetermined angle. 3. A spin processing method for processing an object to be processed with a processing liquid to which ultrasonic vibration has been applied, wherein: a step of holding and rotating the object to be processed; and applying ultrasonic vibration to the processing liquid. Driving the ultrasonic nozzle body to be ejected along the radial direction of the workpiece to be held and rotated by the rotary table; and extending the ultrasonic nozzle body on the extension of the driving direction of the ultrasonic nozzle body. Detecting a sound pressure of an ultrasonic wave applied to the processing liquid by the ultrasonic nozzle body at a standby position outside a peripheral edge in a radial direction of the object.