JP7603437B2 - Substrate processing apparatus and sound pressure sensor - Google Patents

Description

The present invention relates to a substrate processing apparatus that performs cleaning processing by immersing a substrate in a cleaning liquid, and a sound pressure sensor used therein.

Patent Document 1 discloses a substrate processing apparatus that cleans a substrate immersed in a cleaning liquid by applying ultrasonic vibrations to the cleaning liquid. The substrate processing apparatus has a vibrator that vibrates the cleaning liquid, and an oscillator that outputs an electrical signal to the vibrator to vibrate the vibrator.

JP 2011-183300 A

Incidentally, in the case of a substrate processing apparatus such as that described in Patent Document 1, one of the substrate cleaning conditions may include the frequency of ultrasonic vibration. Therefore, it is necessary to check the state of the oscillator and vibrator periodically with a high degree of reliability. To achieve such a reliable check, it is necessary to detect with high sensitivity the vibration of the cleaning liquid vibrated by the oscillator and vibrator in order to suppress the effects of noise, etc.

The present invention aims to detect the vibration of a cleaning liquid with high sensitivity in a cleaning processing apparatus that vibrates a cleaning liquid, such as a substrate processing apparatus that includes a vibrator that vibrates the cleaning liquid and an oscillator that outputs an electrical signal to the vibrator.

In order to solve the above-mentioned problems, according to one aspect of the present invention,
a cleaning tank for storing a cleaning liquid in which the substrate is immersed;
A vibrator that vibrates the cleaning solution;
an oscillator that outputs an electrical signal to the vibrator to vibrate the vibrator;
a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects vibration of the medium;
the sound pressure sensor includes a piezoelectric body that converts vibration of the medium into an electric signal;
a resonant frequency band of the vibrator and a resonant frequency band of the piezoelectric body include a common frequency band,
There is provided a substrate processing apparatus in which, when the sound pressure sensor detects vibration, the oscillator outputs to the vibrator an electric signal for vibrating the vibrator at a frequency included in the common frequency band.

According to another aspect of the present invention,
a cleaning tank for storing a cleaning liquid in which the substrate is immersed;
A vibrator that vibrates the cleaning solution;
an oscillator that outputs an electrical signal to the vibrator to vibrate the vibrator;
a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects vibration of the medium;
the sound pressure sensor includes a sensor housing immersed in the medium, and a piezoelectric body accommodated in the sensor housing and configured to convert vibrations of the sensor housing into an electric signal;
a resonant frequency band of the transducer and a resonant frequency band of the sensor housing include a common frequency band;
There is provided a substrate processing apparatus in which, when the sound pressure sensor detects vibration, the oscillator outputs to the vibrator an electric signal for vibrating the vibrator at a frequency included in the common frequency band.

Furthermore, according to yet another aspect of the present invention,
In a cleaning processing apparatus having a cleaning tank for storing a cleaning liquid, a vibrator for vibrating the cleaning liquid, and an oscillator for outputting an electric signal to the vibrator to vibrate the vibrator, there is provided a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects vibration of the medium,
a piezoelectric body that converts vibration of the medium into an electric signal;
There is provided a sound pressure sensor in which at least a part of a resonant frequency band of the piezoelectric body is common to at least a part of a resonant frequency band of the vibrator and includes a frequency at which the vibrator vibrates.

According to yet another aspect of the present invention,
In a cleaning processing apparatus having a cleaning tank for storing a cleaning liquid, a vibrator for vibrating the cleaning liquid, and an oscillator for outputting an electric signal to the vibrator to vibrate the vibrator, there is provided a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects vibration of the medium,
a sensor housing that is immersed in the medium;
a piezoelectric body that is accommodated in the sensor housing and converts vibrations of the sensor housing into an electrical signal;
There is provided a sound pressure sensor in which at least a part of a resonant frequency band of the sensor housing is common to at least a part of a resonant frequency band of the transducer and includes a frequency at which the transducer vibrates.

According to the present invention, in a cleaning processing apparatus that vibrates a cleaning liquid, such as a substrate processing apparatus that includes a vibrator that vibrates the cleaning liquid and an oscillator that outputs an electrical signal to the vibrator, it is possible to detect the vibration of the cleaning liquid with high sensitivity.

1 is a schematic diagram of a substrate processing apparatus according to a first embodiment of the present invention; FIG. FIG. 1 is a block diagram showing a control system in a substrate processing apparatus according to a first embodiment. FIG. 1 is a diagram showing the relationship between the resonant frequency bands of a transducer, a sensor housing, and a piezoelectric body of a sound pressure sensor in the first embodiment; FIG. 1A shows an example of a voltage waveform of a piezoelectric body of a sound pressure sensor when the vibrator vibrates at a frequency within a common frequency band, and FIG. 1B shows an example of a voltage waveform of a piezoelectric body of a sound pressure sensor when the vibrator vibrates at a frequency outside the common frequency band. FIG. 1 shows the substrate processing apparatus in a state where the substrate is not immersed in the cleaning liquid in the cleaning tank. FIG. 1 is a diagram showing a substrate processing apparatus according to an improved embodiment of the present invention; 1 is a schematic diagram of a substrate processing apparatus according to a second embodiment of the present invention; FIG. 13 is a diagram showing the relationship between the resonant frequency bands of the transducer, the sensor housing, and the piezoelectric body of the sound pressure sensor in the second embodiment. FIG. 13 is a diagram showing a substrate processing apparatus according to an improved embodiment of the present invention; 1 is a schematic diagram of a substrate processing apparatus according to another embodiment of the present invention; FIG. 13 is a schematic diagram of a substrate processing apparatus according to still another embodiment of the present invention.

A substrate processing apparatus according to one aspect of the present invention includes a cleaning tank that stores a cleaning liquid in which a substrate is immersed, a vibrator that vibrates the cleaning liquid, an oscillator that outputs an electrical signal to the vibrator to vibrate the vibrator, and a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects the vibration of the medium, the sound pressure sensor including a piezoelectric body that converts the vibration of the medium into an electrical signal, a common frequency band is included in the resonant frequency band of the vibrator and the resonant frequency band of the piezoelectric body, and when the sound pressure sensor detects the vibration, the oscillator outputs an electrical signal to the vibrator to vibrate the vibrator at a frequency included in the common frequency band.

According to this embodiment, in a cleaning processing apparatus that vibrates a cleaning liquid, such as a substrate processing apparatus that includes a vibrator that vibrates the cleaning liquid and an oscillator that outputs an electrical signal to the vibrator, the vibration of the cleaning liquid can be detected with high sensitivity. In this specification, the term "medium" refers to a substance that has fluidity and can transmit vibrations.

For example, the sound pressure sensor may include a sensor housing that is immersed in the medium, and the piezoelectric element may be housed within the sensor housing and convert vibrations of the sensor housing into an electrical signal.

For example, the common frequency band may be included in the resonant frequency band of the sensor housing.

A substrate processing apparatus according to another aspect of the present invention includes a cleaning tank that stores a cleaning liquid in which a substrate is immersed, a vibrator that vibrates the cleaning liquid, an oscillator that outputs an electrical signal to the vibrator to vibrate the vibrator, and a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects the vibration of the medium, and the sound pressure sensor includes a sensor housing that is immersed in the medium and a piezoelectric body that is housed in the sensor housing and converts the vibration of the sensor housing into an electrical signal, and a common frequency band is included in the resonant frequency band of the vibrator and the resonant frequency band of the sensor housing, and when the sound pressure sensor detects the vibration, the oscillator outputs an electrical signal to the vibrator to vibrate the vibrator at a frequency included in the common frequency band.

According to this aspect, in a cleaning processing apparatus that vibrates a cleaning liquid, such as a substrate processing apparatus that includes a vibrator that vibrates the cleaning liquid and an oscillator that outputs an electrical signal to the vibrator, the vibration of the cleaning liquid can be detected with high sensitivity.

For example, the sensor housing may be made of metal and covered with quartz.

For example, the vibrator may include a piezoelectric body having a resonant frequency band that includes the common frequency band.

For example, a cleaning frequency required for cleaning a substrate may be included in the common frequency band, and when the sound pressure sensor detects vibration, the vibrator may vibrate at the cleaning frequency.

A further aspect of the present invention relates to a sound pressure sensor in a cleaning processing apparatus having a cleaning tank for storing a cleaning liquid, a vibrator for vibrating the cleaning liquid, and an oscillator for outputting an electrical signal to the vibrator to vibrate the vibrator. The sound pressure sensor is immersed in a medium vibrated by the vibrator and detects the vibration of the medium, and includes a piezoelectric body that converts the vibration of the medium into an electrical signal, and at least a portion of the resonant frequency band of the piezoelectric body is common to at least a portion of the resonant frequency band of the vibrator and includes the frequency at which the vibrator vibrates.

According to this aspect, in a cleaning processing apparatus that vibrates a cleaning liquid, such as a substrate processing apparatus that includes a vibrator that vibrates the cleaning liquid and an oscillator that outputs an electrical signal to the vibrator, the vibration of the cleaning liquid can be detected with high sensitivity.

For example, the piezoelectric element may include multiple piezoelectric elements with different resonant frequency bands.

For example, the medium may be a cleaning liquid stored in the cleaning tank.

A sound pressure sensor according to yet another aspect of the present invention is a sound pressure sensor in a cleaning processing apparatus having a cleaning tank for storing a cleaning liquid, a vibrator for vibrating the cleaning liquid, and an oscillator for outputting an electrical signal to the vibrator to vibrate the vibrator, the sound pressure sensor being immersed in a medium vibrated by the vibrator and detecting the vibration of the medium, the sound pressure sensor having a sensor housing immersed in the medium, and a piezoelectric body contained within the sensor housing for converting the vibration of the sensor housing into an electrical signal, at least a portion of the resonant frequency band of the sensor housing is common to at least a portion of the resonant frequency band of the vibrator and includes the frequency at which the vibrator vibrates.

According to this aspect, in a cleaning processing apparatus that vibrates a cleaning liquid, such as a substrate processing apparatus that includes a vibrator that vibrates the cleaning liquid and an oscillator that outputs an electrical signal to the vibrator, the vibration of the cleaning liquid can be detected with high sensitivity.

The following describes an embodiment of the present invention with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram of a substrate processing apparatus according to a first embodiment of the present invention.

As shown in FIG. 1, the substrate processing apparatus 10 according to the first embodiment includes a cleaning tank 12 that stores a cleaning liquid CL, a vibrator 14 that vibrates the cleaning liquid CL, an oscillator 16 that outputs an electrical signal to the vibrator 14, and a control device 18 that controls the oscillator 16.

The cleaning tank 12 is a tank that stores the cleaning liquid CL, in which the workpiece to be cleaned, such as a substrate W, such as a semiconductor wafer, is immersed.

The transducer 14 is a member that ultrasonically vibrates the cleaning liquid CL in the cleaning tank 12. In the case of the first embodiment, the transducer 14 includes a transducer housing 20 made of a metal material such as SUS, a piezoelectric body 22 disposed therein that converts an electrical signal (voltage signal) into vibration, and electrodes and wiring (not shown) for applying a voltage to the piezoelectric body 22. The piezoelectric body 22 is made of, for example, lead zirconate titanate (PZT: Piezo Electric Titanate). When the piezoelectric body 22 vibrates due to an electrical signal S1 from the oscillator 16, the transducer 14 vibrates, and as a result, the cleaning liquid CL is vibrated.

In the case of the first embodiment, the vibrator 14 is provided in the propagation tank 24 and vibrates the cleaning liquid CL in the cleaning tank 12 via the propagation tank 24. Specifically, a vibration transmission medium ML such as water is stored in the propagation tank 24, and the cleaning tank 12 is placed in the vibration transmission medium ML. In other words, the vibrator 14 is not in direct contact with the cleaning liquid CL, but is indirectly in contact with the cleaning liquid CL via the cleaning tank 12, the vibration transmission medium ML, and the propagation tank 24.

The oscillator 16 is a device that outputs an electrical signal (voltage signal) S1 to the transducer 14 (its piezoelectric body 22) to cause the transducer 14 to ultrasonically vibrate. Further details of the oscillator 16 will be described later.

The control device 18 outputs an electric signal (control signal) S2 to the oscillator 16, which causes the oscillator 16 to output an electric signal S1 to the vibrator 14 for ultrasonically vibrating the vibrator 14. The control device 18 is composed of, for example, a CPU and a storage device such as a memory or a hard disk that stores programs that cause the CPU to perform various functions. The control device 18 outputs an electric signal S2 to the oscillator 16, and the oscillator 16 to which the electric signal S2 is input outputs a corresponding electric signal S1 to the vibrator 14, and the vibrator 14 to which the electric signal S1 is input vibrates ultrasonically, thereby ultrasonically vibrating the cleaning liquid CL. As a result, the substrate W in the cleaning liquid CL is ultrasonically cleaned.

Furthermore, in the case of this embodiment 1, the substrate processing apparatus 10 has a sound pressure sensor 30 that is immersed in the cleaning liquid CL in the cleaning tank 12 and detects the sound pressure (i.e., vibration) of the cleaning liquid CL.

In the case of this embodiment 1, the sound pressure sensor 30 includes a sensor housing 32 that is immersed in the cleaning liquid CL, a piezoelectric body 34 that is placed inside the sensor housing 32 and converts vibrations into an electrical signal S3 (voltage signal), and electrodes and wiring (not shown) for drawing out the voltage generated by the piezoelectric body 34.

The piezoelectric body 34 of the sound pressure sensor 30 is protected from the cleaning liquid CL by being housed in the sensor housing 32. Therefore, the piezoelectric body 34 receives the ultrasonic vibrations of the cleaning liquid CL via the sensor housing 32. That is, the piezoelectric body 34 receives the vibrations of the sensor housing 32 that are vibrated by the cleaning liquid CL. The piezoelectric body 34 converts the received ultrasonic vibrations into an electrical signal (voltage signal) S3 and outputs it. The electrical signal S3 of the piezoelectric body 34 is finally output to the control device 18 and the oscilloscope 36.

The sensor housing 32 of the sound pressure sensor 30 is made of a metal material that is not easily corroded by the cleaning liquid CL, such as SUS. In the case of this embodiment 1, the sensor housing 32 is fixed in the cleaning tank 12 so that it is immersed in the cleaning liquid CL and can vibrate. The position in the cleaning tank 12 where the sound pressure sensor 30 is located is preferably directly above the transducer 14. However, a position other than between the transducer 14 and the substrate W is preferable. This is because there is a possibility that part of the ultrasonic vibration from the transducer 14 will be blocked by the sound pressure sensor 30 and will not be transmitted sufficiently to the substrate W.

The oscilloscope 36 displays the waveform of the electrical signal S3 corresponding to the ultrasonic vibration waveform of the cleaning liquid CL, i.e., the voltage waveform generated by the piezoelectric body 34 due to the ultrasonic vibration of the cleaning liquid CL. This allows the operator of the substrate processing apparatus 10 to monitor the ultrasonic vibration waveform.

In the present embodiment 1, the control device 18 is configured to execute a state determination of the vibrator 14 and the oscillator 16 based on the electrical signal S3 of the piezoelectric body 34 of the sound pressure sensor 30. In other words, the control device 18 is configured to determine whether or not the piezoelectric body 34 of the sound pressure sensor 30 is outputting the corresponding electrical signal S3 when a predetermined electrical signal S2 is input from the control device 18 to the oscillator 16.

Figure 2 is a block diagram showing the control system in the substrate processing apparatus according to the first embodiment.

2, in order to execute state determination of the transducer 14 and the oscillator 16, the control device 18 has an oscillator control unit 40 that controls the oscillator 16, a vibration waveform acquisition unit 42 that acquires the waveform (vibration waveform) of the ultrasonic vibration detected by the sound pressure sensor 30, a transducer/oscillator state determination unit 44 that determines the state of the transducer 14 and the oscillator 16 based on the vibration waveform acquired by the vibration waveform acquisition unit 42, and a memory unit 46 that stores the acquired vibration waveform. When the control device 18 is composed of a CPU and a memory unit 46, the CPU operates according to a program stored in the memory unit 46, whereby the CPU functions as the oscillator control unit 40, the vibration waveform acquisition unit 42, and the transducer/oscillator state determination unit 44.

When the oscillator control unit 40 executes state determination of the vibrator 14 and the oscillator 16, it outputs a corresponding state stabilization electrical signal Sc to the oscillator 16 so that the vibrator 14 vibrates at the state determination frequency fc. This state determination frequency fc will be described later.

The oscillator control unit 40 may be a dedicated control unit that controls the oscillator only when performing state determination, or it may be a control unit that controls the oscillator when cleaning the substrate W.

The vibration waveform acquisition unit 42 acquires the vibration waveform detected by the sound pressure sensor 30 when the vibrator 14 is vibrating at the state determination frequency fc. The acquired vibration waveform may be presented to the worker via an output device 50 such as a display. The acquired vibration waveform is stored as data in the memory unit 46.

The vibrator/oscillator state determination unit 44 determines the state of the vibrator 14 and the oscillator 16 based on the vibration waveform acquired by the vibration waveform acquisition unit 42. Specifically, the vibrator/oscillator state determination unit 44 compares the most recently acquired past vibration waveform stored in the memory unit 46 with the newly acquired vibration waveform, and performs state determination based on the comparison result. For example, if the frequency deviation exceeds a predetermined deviation amount and/or if the change in amplitude exceeds a predetermined change amount, the vibrator/oscillator state determination unit 44 determines that an abnormality has occurred in at least one of the vibrator 14 and the oscillator 16. The occurrence of the abnormality is then notified to the operator via the output device 50.

In order for the transducer/oscillator state determination unit 44 to perform such state determination with a high degree of reliability, the sound pressure sensor 30 must detect the vibration of the cleaning liquid CL with high sensitivity under certain predetermined conditions. To achieve this, in the case of the first embodiment, first, a common frequency band is included in the resonant frequency band of the transducer 14 and the resonant frequency band of the piezoelectric body 34 of the sound pressure sensor 30.

Figure 3 shows the relationship between the resonant frequency bands of the transducer, the sensor housing, and the piezoelectric body of the sound pressure sensor in embodiment 1.

As shown in FIG. 3, in the case of the first embodiment, the resonant frequency band of the vibrator 14 and the resonant frequency band of the piezoelectric body 34 of the sound pressure sensor 30 include a common frequency band CB (cross-hatched area).

The "resonant frequency band" of the vibrator 14 here refers to the frequency band in which the vibrator 14 is displaced/deformed more than in other frequency bands when the electrical signal S1 to the vibrator 14 is changed. The resonant frequency band of the vibrator 14 varies depending on, for example, the material, shape, rigidity, etc. of the vibrator housing 20 of the vibrator 14 and the material, shape, rigidity, etc. of the piezoelectric body 22, and can be adjusted to the desired band by appropriately adjusting these.

The "resonant frequency band" of the piezoelectric body 34 of the sound pressure sensor 30 referred to here is the frequency band in which, when the frequency of the vibration received by the piezoelectric body 34 is changed, the sensitivity of the piezoelectric body 34 increases significantly compared to other frequency bands, for example, the amplitude of the output signal (voltage signal) increases significantly. The resonant frequency band of the piezoelectric body 34 varies depending on, for example, the material, shape, and rigidity of the piezoelectric body 34, and can be adjusted to the desired band by appropriately adjusting these.

The oscillator 16 outputs an electrical signal corresponding to a state determination frequency fc included in a predetermined common frequency band CB to the transducer 14. This causes the transducer 14 to vibrate at the state determination frequency fc, and ultrasonic vibrations of the state determination frequency fc with a large amplitude are transmitted from the transducer 14 to the piezoelectric body 34 of the sound pressure sensor 30 (compared to when the transducer 14 vibrates at a frequency outside the resonant frequency band). The piezoelectric body 34 that receives the ultrasonic vibrations also resonates and its sensitivity increases, i.e., it outputs a voltage signal with a large amplitude (compared to when the piezoelectric body 34 receives vibrations at a frequency outside the resonant frequency band). As a result, the sound pressure sensor 30 can output a vibration waveform with a high S/N ratio, in which the vibrations of the cleaning liquid CL are not buried in noise, as a detection result.

Therefore, the vibrator/oscillator state determination unit 44 can determine the state of the vibrator 14 and oscillator 16 with a high degree of reliability based on the vibration waveform detected by the sound pressure sensor 30 with high sensitivity under certain conditions (state determination frequency fc).

Figure 4 shows (a) an example of a voltage waveform of the piezoelectric body of the sound pressure sensor when the vibrator vibrates at a frequency within the common frequency band, and (b) an example of a voltage waveform of the piezoelectric body of the sound pressure sensor when the vibrator vibrates at a frequency outside the common frequency band. In the case of Figure 4(a), one scale on the vertical axis indicating voltage represents 50V, and in the case of Figure 4(b), one scale represents 1V.

As shown in FIG. 4, when the vibrator 14 vibrates at a frequency (state determination frequency fc) within the common frequency band CB (case (a)), the piezoelectric body 34 of the sound pressure sensor 30 outputs a voltage signal with a high S/N ratio and large amplitude compared to when it does not (case (b)). Based on such a voltage signal with a high S/N ratio and large amplitude, it becomes possible to determine the state of the vibrator 14 and the oscillator 16 with a high degree of reliability.

Furthermore, in the case of the present embodiment 1, as shown in FIG. 3, the resonant frequency band of the sensor housing 32 of the sound pressure sensor 30 includes the common frequency band CB.

The "resonant frequency band" of the sensor housing 32 here refers to the frequency band in which the sensor housing 32 is displaced/deformed more than in other frequency bands when the frequency of the vibration applied to the sensor housing 32 is changed. The resonant frequency band of the sensor housing 32 varies depending on, for example, the material, shape, and rigidity of the sensor housing 32, and can be adjusted to the desired band by appropriately adjusting these.

With such a sensor housing 32, the ultrasonic vibrations of the state determination frequency fc from the transducer 14 are transmitted to the piezoelectric body 34 while attenuation in the sensor housing 32 is suppressed. As a result, the sensitivity of the piezoelectric body 34 is further increased.

In addition, the state determination frequency ft for determining the state of the vibrator 14 and oscillator 16 is preferably the cleaning frequency.

Specifically, the cleaning conditions for the substrate W immersed in the cleaning liquid CL may include the frequency of ultrasonic vibration (the cleaning frequency required for the cleaning process). For example, depending on the type of substrate, a frequency in the 20-300 kHz band or a frequency of 700 kHz or higher may be determined as the cleaning frequency. In this case, it is preferable that the cleaning frequency is included in the common frequency band CB. By setting the state determination frequency fc to the cleaning frequency, it becomes possible to determine the state of the transducer 14 and oscillator 16 while the substrate W is being cleaned. Furthermore, this determination can ensure that the state of the transducer 14 and oscillator 16 is such that the substrate W can be cleaned.

The timing for determining the state of the vibrator 14 and the oscillator 16 is not limited to when the substrate W is immersed in the cleaning liquid CL in the cleaning tank 12.

Figure 5 shows the substrate not immersed in the cleaning solution in the cleaning tank.

As shown in FIG. 5, the state determination may be performed when the substrate W is not immersed in the cleaning liquid CL in the cleaning tank 12, for example, before the substrate W is loaded into the cleaning liquid CL, or after the substrate W after cleaning processing is loaded out of the cleaning liquid CL. This allows the sound pressure sensor 30 to detect ultrasonic vibrations under more constant conditions without being affected by the substrate W, for example, by a shift in the immersion position of the substrate W.

In addition, the medium for vibration detection by the sound pressure sensor 30 is not limited to the cleaning liquid CL in the cleaning tank 12.

Figure 6 shows a substrate processing apparatus according to an improved embodiment of the first embodiment.

As shown in FIG. 6, the sound pressure sensor 30 may be provided in the propagation tank 24 rather than in the cleaning tank 12 to detect the vibration of the vibration transmission medium ML. Even in this case, the state of the vibrator 14 and the oscillator 16 can be determined in the same way as when detecting the vibration of the cleaning liquid CL in the cleaning tank 12. Furthermore, in this case, it is possible to determine the state of the vibrator 14 and the oscillator 16 regardless of whether the substrate W is immersed in the cleaning liquid CL or not, i.e., under the same conditions.

According to the first embodiment described above, in a substrate processing apparatus including an oscillator that vibrates the cleaning liquid used to clean a substrate and an oscillator that outputs an electrical signal to the oscillator, the vibration of the cleaning liquid or the vibration transmission medium can be detected with high sensitivity.

(Embodiment 2)
The second embodiment differs from the first embodiment in the structure of the sound pressure sensor. Therefore, the second embodiment will be described focusing on the differences. Note that the same reference numerals are used to designate the components of the second embodiment that are substantially the same as those of the first embodiment.

Figure 7 is a schematic diagram of a substrate processing apparatus according to a second embodiment of the present invention. Also, Figure 8 is a diagram showing the relationship between the resonant frequency bands of the transducer, the sensor housing, and the piezoelectric body of the sound pressure sensor in the second embodiment.

As shown in FIG. 7, in the substrate processing apparatus 110 according to the second embodiment, the sound pressure sensor 130 includes a sensor housing 132 that is immersed in the cleaning liquid CL, a piezoelectric body 134 that is disposed inside the sensor housing 132 and converts vibrations into an electrical signal, and electrodes and wiring (not shown) for drawing out the voltage generated by the piezoelectric body 134.

In the case of the sound pressure sensor 130 of the second embodiment, the sensor housing 132 has a double structure, unlike the sensor housing 32 of the sound pressure sensor 30 of the first embodiment described above. Specifically, the sensor housing 132 is composed of a metal housing 132a that houses the piezoelectric body 134, and a quartz cover layer 132b formed on the outer surface of the housing 132a. The reason that the metal housing 132a is covered with the quartz cover layer 132b is that the substrate W to be cleaned is a substrate that is easily affected by metal.

Also, as shown in FIG. 8, the resonant frequency band of the quartz cover layer 132b of the sensor housing 132 is outside the common frequency band CB. If it overlaps with the common frequency band CB, there is a possibility that the quartz cover layer 132b may crack when subjected to vibrations of the state determination frequency ft included in the common frequency band CB.

The double structure of the sensor housing of the sound pressure sensor can be configured in a way other than a configuration consisting of a metal housing and a quartz cover layer formed on the outer surface of the housing.

Figure 9 shows a substrate processing apparatus according to an improved embodiment of the second embodiment.

As shown in FIG. 9, in the substrate processing apparatus 210 according to the improved embodiment of the second embodiment, the sensor housing 232 of the sound pressure sensor 230 is composed of a metal inner housing 232a that houses the piezoelectric body 234, and a cup-shaped outer housing 232b made of quartz that houses the inner housing 232a. The outer housing 232b is filled with a vibration transmission medium 236 such as water for transmitting vibrations from the outer housing 232b to the inner housing 232a.

As with the above-mentioned embodiment 1, the present embodiment 2 can detect the vibration of the cleaning liquid with high sensitivity in a substrate processing apparatus that includes a vibrator that vibrates the cleaning liquid used to clean the substrate and an oscillator that outputs an electrical signal to the vibrator.

In addition, in the second embodiment, the sound pressure sensors 130 and 230 may be provided in the propagation tank 24 to detect the vibration of the vibration transmission medium ML.

The present invention has been described above using the above-mentioned embodiments 1 and 2, but the embodiments of the present invention are not limited to the above-mentioned embodiments.

For example, in the case of the above-mentioned embodiment 1, as shown in FIG. 3, the vibrator 14 vibrates at a state determination frequency fc included in a common frequency band CB that is included in the resonant frequency band of the vibrator 14 and the resonant frequency band of the piezoelectric body 34 of the sound pressure sensor 30. However, the embodiment of the present invention is not limited to this.

The vibrator may vibrate at a frequency in a common frequency band that is included in the resonant frequency band of the vibrator and the resonant frequency band of the sensor housing of the sound pressure sensor, i.e., at a frequency outside the resonant frequency band of the piezoelectric body of the sound pressure sensor. Even in this case, it is possible to detect the vibration of the cleaning liquid with high sensitivity.

In the above-mentioned first and second embodiments, as shown in Figs. 1 and 7, the piezoelectric bodies 34, 134 of the sound pressure sensors 30, 130 are immersed in the cleaning liquid CL while being housed in the sensor housings 32, 132. However, the embodiment of the present invention is not limited to this. If the piezoelectric body of the sound pressure sensor is a waterproof piezoelectric body and does not affect the substrate, it may be immersed in the cleaning liquid without being housed in the sensor housing.

Furthermore, in the case of the above-mentioned embodiment 1, as shown in FIG. 1, the sound pressure sensor 30 is fixed to the cleaning tank 12. Alternatively, the sound pressure sensor may be detachable from the substrate processing apparatus. In this case, a single sound pressure sensor can be shared by multiple substrate processing apparatuses.

If the sound pressure sensor is detachable from the substrate processing apparatus, the sound pressure sensor may include multiple different piezoelectric elements.

Figure 10 is a schematic diagram of a substrate processing apparatus according to another embodiment of the present invention.

As shown in FIG. 10, in a substrate processing apparatus 310 according to another embodiment, a sound pressure sensor 330 that is detachable from the cleaning tank 12 includes three piezoelectric bodies 324A, 324B, and 324C in a sensor housing 332. Each of the three piezoelectric bodies 324A, 324B, and 324C has a different resonant frequency band. Therefore, the sound pressure sensor 330 can be used for a plurality of substrate processing apparatuses each having a different resonant frequency band of the vibrator. This improves the versatility of the sound pressure sensor.

Furthermore, in the case of the above-mentioned embodiment 1, as shown in FIG. 1, the vibrator 14 is provided in the propagation tank 24. That is, the cleaning liquid CL is vibrated by the vibrator 14 via the propagation tank 24, the vibration transmission medium ML, and the cleaning tank 12. However, the embodiment of the present invention is not limited to this.

Figure 11 is a schematic diagram of a substrate processing apparatus according to yet another embodiment of the present invention.

As shown in FIG. 11, a substrate processing apparatus 410 according to yet another embodiment does not include a propagation tank, unlike the first embodiment described above. Therefore, a vibrator 14 is provided in the cleaning tank 12. A sound pressure sensor 30 is also provided in the cleaning tank 12. With this type of substrate processing apparatus 410, the loss of vibration transmitted from the vibrator 14 to the cleaning liquid CL is reduced compared to when a propagation tank is provided.

In other words, a substrate processing apparatus according to one embodiment of the present invention is, in a broad sense, an apparatus that includes a cleaning tank that stores a cleaning liquid in which a substrate is immersed, a vibrator that vibrates the cleaning liquid, an oscillator that outputs an electrical signal to the vibrator to vibrate the vibrator, and a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects the vibration of the medium, the sound pressure sensor includes a piezoelectric body that converts the vibration of the medium into an electrical signal, a common frequency band is included in the resonant frequency band of the vibrator and the resonant frequency band of the piezoelectric body, and when the sound pressure sensor detects the vibration, the oscillator outputs an electrical signal to the vibrator to vibrate the vibrator at a frequency included in the common frequency band.

In addition, a substrate processing apparatus according to another embodiment of the present invention is, in a broad sense, an apparatus that includes a cleaning tank that stores a cleaning liquid in which a substrate is immersed, a vibrator that vibrates the cleaning liquid, an oscillator that outputs an electrical signal to the vibrator to vibrate the vibrator, and a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects the vibration of the medium, the sound pressure sensor including a sensor housing that is immersed in the medium and a piezoelectric body that is housed in the sensor housing and converts the vibration of the sensor housing into an electrical signal, the resonant frequency band of the vibrator and the resonant frequency band of the sensor housing include a common frequency band, and when the sound pressure sensor detects the vibration, the oscillator outputs an electrical signal to the vibrator to vibrate the vibrator at a frequency included in the common frequency band.

As mentioned above, the above-mentioned embodiment has been described as an example of the technology of the present invention. For that purpose, drawings and detailed description are provided. Therefore, among the components described in the drawings and detailed description, not only are there components essential for solving the problem, but there may also be components that are not essential for solving the problem in order to illustrate the above-mentioned technology. Therefore, just because those non-essential components are described in the drawings or detailed description, it should not be immediately determined that those non-essential components are essential.

In addition, the above-described embodiment is intended to illustrate the technology of the present invention, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

The present invention is applicable to cleaning processing apparatuses such as substrate processing apparatuses that include a vibrator and an oscillator that outputs an electrical signal to the vibrator to cause it to vibrate.

REFERENCE SIGNS LIST 10 Substrate processing apparatus 12 Cleaning tank 14 Transducer 16 Oscillator 30 Sound pressure sensor 34 Piezoelectric body CL Cleaning liquid W Substrate

Claims (9)

a cleaning tank for storing a cleaning liquid in which the substrate is immersed;
A vibrator that vibrates the cleaning solution;
an oscillator that outputs an electrical signal to the vibrator to vibrate the vibrator;
a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects vibration of the medium;
the sound pressure sensor includes a sensor housing immersed in the medium, and a piezoelectric body accommodated in the sensor housing and configured to convert vibrations of the sensor housing into an electric signal;
a resonant frequency band of the transducer and a resonant frequency band of the sensor housing include a common frequency band;
When the sound pressure sensor detects vibration, the oscillator outputs an electric signal to the vibrator for vibrating the vibrator at a frequency included in the common frequency band.
The substrate processing apparatus according to claim 1 , wherein the common frequency band is included in a resonant frequency band of the piezoelectric body.
The substrate processing apparatus according to claim 1 , wherein the sensor housing is made of metal and covered with quartz.
The substrate processing apparatus according to claim 1 , wherein the vibrator includes a piezoelectric body having a resonant frequency band including the common frequency band.
A cleaning frequency required for the cleaning process of the substrate is included in the common frequency band,
The substrate processing apparatus according to claim 1 , wherein the vibrator vibrates at the cleaning frequency when the sound pressure sensor detects vibration.
The substrate processing apparatus according to claim 1 , wherein the medium is a cleaning liquid stored in the cleaning tank.
In a cleaning processing apparatus having a cleaning tank for storing a cleaning liquid, a vibrator for vibrating the cleaning liquid, and an oscillator for outputting an electric signal to the vibrator to vibrate the vibrator, there is provided a sound pressure sensor that is immersed in a medium vibrated by the vibrator and detects vibration of the medium,
a sensor housing that is immersed in the medium;
a piezoelectric body that is accommodated in the sensor housing and converts vibrations of the sensor housing into an electrical signal;
A sound pressure sensor, wherein at least a portion of a resonant frequency band of the sensor housing is common to at least a portion of a resonant frequency band of the transducer and includes a frequency at which the transducer vibrates.
The sound pressure sensor according to claim 7 , wherein a frequency band commonly included in the resonant frequency band of the sensor housing and the resonant frequency band of the vibrator is included in a resonant frequency band of the piezoelectric body of the sound pressure sensor.
9. The sound pressure sensor according to claim 7, wherein the piezoelectric element of the sound pressure sensor includes a plurality of piezoelectric elements having different resonant frequency bands.

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