JP2004048484A - Sound pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound pressure sensor capable of highly precisely detecting ultrasonic vibration. <P>SOLUTION: This sound pressure sensor for detecting the sound pressure of ultrasonic vibration is provided with a waveguide 2 whose top end part is formed on an incident face 4 of ultrasonic vibration, a piezoelectric element 6 arranged at the rear edge of this waveguide for converting the sound pressure of ultrasonic vibration made incident from the incident face to the waveguide, and propagated to the rear edge into an electric signal, and an overcoat body 3 from which the incident face of the top end part of the waveguide is exposed wherein the outer peripheral face is liquid-tightly covered through an air layer 9. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic sensor for measuring the intensity of ultrasonic vibration when performing cleaning using ultrasonic vibration.
[0002]
[Prior art]
In semiconductor manufacturing processes and liquid crystal panel manufacturing processes, ultrasonic waves are used to clean and remove submicron-order particles attached to substrates such as semiconductor wafers and glass substrates before and after microfabrication to form circuit patterns. Washing is performed. This cleaning step is a very important step in improving the production yield of the substrate.
[0003]
As an apparatus for performing such cleaning, an ultrasonic cleaning apparatus is known. In an ultrasonic cleaning apparatus, it is important to know the sound pressure distribution state of ultrasonic vibration at a surface portion of a substrate or at various portions in a cleaning tank in order to make the cleaning accuracy of a substrate uniform.
[0004]
In other words, whether the ultrasonic oscillator for ultrasonically oscillating the ultrasonic vibrator is operating normally and whether the ultrasonic vibration generated by the ultrasonic vibrator is efficiently applied to the cleaning liquid, A sound pressure sensor is used to detect whether or not the distribution of the intensity of the ultrasonic vibration in the cleaning tank is uneven.
[0005]
In general, a sound pressure sensor has a waveguide made of a material such as resin or glass and having a distal end formed on an incident surface on which ultrasonic vibration is incident. A piezoelectric element for converting vibration into an electric signal is provided on the end face. A display unit is electrically connected to the piezoelectric element via an amplifier.
[0006]
Thereby, the ultrasonic vibration incident on the vibration receiving portion at the distal end of the waveguide propagates through the waveguide and is converted into an electric signal by the piezoelectric element provided at the enlarged diameter portion at the base end. It has become.
[0007]
[Problems to be solved by the invention]
In the sound pressure sensor having the above configuration, when measuring the distribution state of the ultrasonic vibrations in the cleaning tank, the waveguide is immersed in the cleaning liquid contained in the cleaning tank, and the measurement target portion in the cleaning tank is measured. Is measured.
[0008]
In this case, the incident surface at the tip of the waveguide is directed to the oscillation source of the ultrasonic vibration. Thereby, the ultrasonic vibration from the oscillation source can be surely made to enter the waveguide from the incident surface.
[0009]
However, since the ultrasonic vibration oscillated from the oscillation source is reflected on the inner surface of the cleaning tank and the object to be cleaned, the ultrasonic vibration does not always proceed in a fixed direction in the cleaning tank. Therefore, even if the incident surface at the tip of the waveguide is directed to the oscillation source, the ultrasonic vibration may enter the waveguide not only from the incident surface but also from the outer peripheral surface. Then, since the ultrasonic vibration incident from the outer peripheral surface of the waveguide becomes a disturbance factor, the intensity of the ultrasonic vibration at a desired portion may not be accurately measured.
[0010]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a sound pressure sensor that prevents ultrasonic vibration from being incident from the outer peripheral surface of a waveguide.
[0011]
[Means for Solving the Problems]
The invention according to claim 1 is a sound pressure sensor for detecting a sound pressure of ultrasonic vibration,
A waveguide whose tip is formed on the incident surface of the ultrasonic vibration,
A piezoelectric element that is provided at the rear end of the waveguide and converts the sound pressure of the ultrasonic vibration that has entered the waveguide from the incident surface and propagated to the rear end into an electric signal;
An outer jacket that exposes the incident surface of the distal end of the waveguide and liquid-tightly covers the outer peripheral surface via an air layer,
A sound pressure sensor comprising:
[0012]
The invention according to claim 2 is characterized in that the mantle is
A tubular member in which the waveguide is housed and an opening for exposing the incident surface of the waveguide is formed at the tip and a rear end face is opened,
A pressing portion that is detachably provided at the rear end of the tubular member, closes the rear end opening, and presses the rear end surface of the waveguide against the inner surface to hold the waveguide inside the tubular member. 2. The sound pressure sensor according to claim 1, further comprising: a cover member provided with a cover member.
[0013]
According to the present invention, since the outer peripheral surface of the waveguide is covered with the mantle via the air layer, the ultrasonic vibration is reflected on the boundary surface between the air layer and the mantle and enters the waveguide. Nothing.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 shows a sound pressure sensor 1 according to an embodiment of the present invention. The sound pressure sensor 1 is composed of a waveguide 2 and a jacket 3. The waveguide 2 is formed in a hollow shape by using a material such as resin or quartz, the front end surface is formed on an incident surface 4 on which ultrasonic vibration is incident as described later, and the rear end portion is a base end portion 5. ing.
[0016]
The ultrasonic vibration incident on the waveguide 2 from the incident surface 4 propagates in the waveguide 2 and the sound pressure is reduced by the piezoelectric element 6 provided on the end face of the base end 5 of the waveguide 2. It is converted to a signal.
[0017]
The mantle 3 has a cylindrical member 8 formed of a material such as resin or quartz, similarly to the waveguide 2. The tubular member 8 has a larger diameter than the waveguide 2 and houses the waveguide 2 therein. Thereby, a space, that is, an air layer 9 is formed between the waveguide 2 and the cylindrical member 8.
[0018]
An opening 11 having a diameter smaller than that of the waveguide 2 and exposing the incident surface 4 of the waveguide 2 is formed in a distal end surface of the tubular member 8. An O-ring 12 is provided between the inner surface of the distal end of the cylindrical member 8 and the incident surface 4 of the waveguide 2, and the opening 11 is closed by the O-ring 12 in a liquid-tight manner.
[0019]
The rear end surface of the tubular member 8 is open, and this opening is closed by a lid member 13 which is detachably screwed to the tubular member 8. On the inner surface of the lid member 13, a cylindrical pressing portion 14 having a smaller diameter than the base end portion 5 of the waveguide 2 protrudes.
[0020]
When the lid member 13 is screwed to the rear end of the tubular member 8, the pressing portion 14 presses the rear end surface of the base end 5. As a result, the O-ring 12 provided between the incident surface 4 of the waveguide 2 and the inner surface of the cylindrical member 8 is elastically compressed. It will be liquid-tightly closed by the entrance surface 4.
[0021]
A lead wire 15 is connected to the piezoelectric element 6. The lead wire 15 is connected to an amplifier 17 via a cable retainer 16 provided on the lid member 13. The electric signal converted by the piezoelectric element 6 is amplified by the amplifier 17, and its waveform is displayed on a display 18.
[0022]
The sound pressure sensor 1 having the above configuration is used as shown in FIG. FIG. 2 shows a cleaning tank 21 for cleaning an object to be cleaned such as a semiconductor wafer or a glass substrate. The cleaning liquid L is contained in the cleaning tank 21.
[0023]
An opening 22 is formed at the bottom of the cleaning tank 21, and the opening 22 is liquid-tightly closed by a diaphragm 24 via a packing 23. An ultrasonic vibrator 25 is provided on the lower surface of the vibration plate 24. The ultrasonic oscillator 25 is supplied with high-frequency power from an ultrasonic oscillator 26. As a result, the ultrasonic vibrator 25 ultrasonically vibrates, and the vibration plate 24 vibrates together with the ultrasonic vibrator 25. Therefore, the ultrasonic vibration of the vibration plate 24 is transmitted to the cleaning liquid in the cleaning tank 21. Has become.
[0024]
When measuring the intensity of the ultrasonic vibration transmitted to the cleaning liquid, the sound pressure sensor 1 is immersed and positioned in the cleaning liquid L as shown in FIG. 2, and the vibration plate 24 is ultrasonically vibrated. In this case, the end face of the sound pressure sensor 1, that is, the opening 11 where the incident surface 4 of the waveguide 2 is exposed is directed toward the diaphragm 24 as an oscillation source.
[0025]
As a result, the ultrasonic vibration propagated through the cleaning liquid L is incident on the incident surface 4 of the waveguide 2 from the opening 11 of the sound pressure sensor 1, propagates through the waveguide 2, and is converted into an electric signal by the piezoelectric element 6. Therefore, the intensity of the ultrasonic vibration at a predetermined position can be measured.
[0026]
In such a measurement, the ultrasonic vibration that has propagated the cleaning liquid is incident not only on the incident surface 4 of the sound pressure sensor 1 but also on the outer peripheral surface of the mantle 3. However, an air layer 9 is formed between the mantle 3 and the waveguide 2. Since the impedance of the acoustic wave differs between the mantle 3 and the air layer 9, the ultrasonic vibrations incident on the mantle 3 are totally reflected at the boundary between the mantle 3 and the air layer 9, and pass through the waveguide 2. It does not propagate.
[0027]
Therefore, the ultrasonic vibration is incident on the waveguide 2 only from the incident surface 4 at the tip, and does not enter from the other than the incident surface 4. Does not become a disturbance factor and the intensity of ultrasonic vibration at a desired portion cannot be measured accurately.
[0028]
The mantle body 3 containing the waveguide 2 is composed of a tubular member 8 and a lid member 13 which is detachably screwed to the tubular member 8. The waveguide 2 is attached to the tubular member 8. After being accommodated, the waveguide 2 can be held and fixed inside by attaching the lid member 13. Therefore, since the waveguide 2 can be easily attached to and detached from the mantle 2, maintenance and inspection of the waveguide 2 can be easily performed.
[0029]
【The invention's effect】
As described above, according to the present invention, the outer peripheral surface of the waveguide is covered by the mantle via the air layer.
[0030]
Therefore, since the ultrasonic vibration is reflected at the boundary between the air layer and the mantle, and does not enter the waveguide, the intensity of the ultrasonic vibration at a desired portion can be accurately measured.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a configuration of a sound pressure sensor according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram for measuring a sound pressure in a cleaning tank by a sound pressure sensor.
[Explanation of symbols]
2. Waveguide 3 ... Mantle 4 ... Incident surface 6 ... Piezoelectric element 8 ... Cylindrical member 9 ... Air layer 13 ... Lid member

Claims (2)

In a sound pressure sensor for detecting the sound pressure of ultrasonic vibration,
A waveguide whose tip is formed on the incident surface of the ultrasonic vibration,
A piezoelectric element that is provided at the rear end of the waveguide and converts the sound pressure of the ultrasonic vibration that has entered the waveguide from the incident surface and propagated to the rear end into an electric signal;
An outer jacket that exposes the incident surface of the distal end of the waveguide and liquid-tightly covers the outer peripheral surface via an air layer,
A sound pressure sensor comprising: The mantle is
A tubular member in which the waveguide is housed and an opening for exposing the incident surface of the waveguide is formed at the tip and a rear end face is opened,
A pressing portion that is detachably provided at the rear end of the tubular member, closes the rear end opening, and presses the rear end surface of the waveguide against the inner surface to hold the waveguide inside the tubular member. The sound pressure sensor according to claim 1, further comprising: a lid member provided with a cover member.

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