Substrate processing apparatus and sound pressure sensor

Abstract

To detect vibration of a cleaning liquid of a substrate processing device with high sensitivity.SOLUTION: A substrate processing device 10 includes a cleaning tank 12 that stores a cleaning liquid CL in which a substrate W is immersed, a vibrator 14 that vibrates the cleaning liquid CL, an oscillator 16 that outputs an electric signal to the vibrator 14 to vibrate the vibrator 14, and a sound pressure sensor 30 that is immersed in the cleaning liquid CL to detect vibration. The sound pressure sensor 30 includes a piezoelectric body 34 that converts vibration into an electric signal. A frequency band common to the resonance frequency band of the vibrator 14 and the resonance frequency band of the piezoelectric body 34 is included. When the sound pressure sensor 30 detects vibration, the oscillator 16 outputs, to the vibrator 14, an electric signal for vibrating the vibrator 14 at a frequency included in a common frequency band.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a substrate processing apparatus that performs a cleaning process by immersing a substrate in a cleaning liquid, and a sound pressure sensor used therein. [Background technology]

[0002] Patent Document 1 discloses a substrate processing apparatus that cleans a substrate immersed in a cleaning liquid by applying ultrasonic vibration to the cleaning liquid. The substrate processing apparatus has a vibrator that vibrates the cleaning liquid and an oscillator that outputs an electric signal to the vibrator to vibrate the vibrator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-183300 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the case of a substrate processing apparatus as described in Patent Document 1, one of the substrate cleaning conditions may include the frequency of ultrasonic vibration. Therefore, it is necessary to periodically check the state of the oscillator and vibrator with high reliability. In order to realize such a highly reliable check, it is necessary to detect the vibration of the cleaning liquid vibrated by the oscillator and vibrator with high sensitivity in order to suppress the influence of noise, etc.

[0005] Therefore, an object of the present invention is 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. [Means for solving the problem]

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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. Effect of the Invention

[0010] 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, the vibration of the cleaning liquid can be detected with high sensitivity. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a substrate processing apparatus according to a first embodiment of the present invention; FIG. [Diagram 2] FIG. 1 is a block diagram showing a control system in a substrate processing apparatus according to a first embodiment. [Diagram 3] 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. [Figure 4]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. [Diagram 5] FIG. 1 shows the substrate processing apparatus in a state where the substrate is not immersed in the cleaning liquid in the cleaning tank. [Figure 6] FIG. 1 is a diagram showing a substrate processing apparatus according to an improved embodiment of the first embodiment; [Figure 7] 1 is a schematic diagram of a substrate processing apparatus according to a second embodiment of the present invention; [Figure 8] 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. [Figure 9] FIG. 13 is a diagram showing a substrate processing apparatus according to an improved embodiment of the second embodiment. [Figure 10] 1 is a schematic diagram of a substrate processing apparatus according to another embodiment of the present invention; [Figure 11] FIG. 13 is a schematic diagram of a substrate processing apparatus according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A substrate processing apparatus according to one embodiment of the present invention has a cleaning tank for storing a cleaning liquid in which a substrate is immersed, a vibrator for vibrating the cleaning liquid, an oscillator for outputting an electrical signal to the vibrator to vibrate the vibrator, and a sound pressure sensor for being immersed in a medium vibrated by the vibrator and detecting the vibration of the medium, wherein the sound pressure sensor includes a piezoelectric body for converting 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 for vibrating the vibrator at a frequency included in the common frequency band.

[0013] 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 electric signal to the vibrator, it is possible to detect the vibration of the cleaning liquid with high sensitivity. Note that in this specification, the term "medium" refers to a substance that has fluidity and can transmit vibrations.

[0014] For example, the sound pressure sensor may include a sensor housing that is immersed in the medium, and the piezoelectric element may be accommodated within the sensor housing to convert vibrations of the sensor housing into an electrical signal.

[0015] For example, the common frequency band may be included in a resonant frequency band of the sensor housing.

[0016] A substrate processing apparatus according to another aspect of the present invention has a cleaning tank for storing a cleaning liquid in which a substrate is immersed, a vibrator for vibrating the cleaning liquid, an oscillator for outputting an electrical signal to the vibrator to vibrate the vibrator, and a sound pressure sensor immersed in a medium vibrated by the vibrator and detecting the vibration of the medium, wherein the sound pressure sensor includes 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, wherein 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 vibration, the oscillator outputs an electrical signal to the vibrator for vibrating the vibrator at a frequency included in the common frequency band.

[0017] 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.

[0018] For example, the sensor housing may be metallic and covered with quartz.

[0019] For example, the vibrator may include a piezoelectric body having a resonant frequency band that includes the common frequency band.

[0020] For example, a cleaning frequency required for a substrate cleaning process may be included in the common frequency band, and when the sound pressure sensor detects vibration, the oscillator may vibrate at the cleaning frequency.

[0021] According to yet another aspect of the present invention, a sound pressure sensor is provided 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 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 a frequency at which the vibrator vibrates.

[0022] 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.

[0023] For example, the piezoelectric element may include a plurality of piezoelectric elements having different resonant frequency bands.

[0024] For example, the medium may be a cleaning liquid stored in the cleaning tank.

[0025] According to yet another aspect of the present invention, a sound pressure sensor is provided 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 vibrations of the medium, and has a sensor housing immersed in the medium, and a piezoelectric body contained within the sensor housing for converting the vibrations of the sensor housing into an electrical signal, and 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 a frequency at which the vibrator vibrates.

[0026] 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.

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0028] (Embodiment 1) FIG. 1 is a schematic diagram of a substrate processing apparatus according to a first embodiment of the present invention.

[0029] As shown in FIG. 1, a substrate processing apparatus 10 according to the first embodiment includes a cleaning tank 12 for storing a cleaning liquid CL, an oscillator 14 for vibrating the cleaning liquid CL, an oscillator 16 for outputting an electrical signal to the oscillator 14, and a control device 18 for controlling the oscillator 16.

[0030] The cleaning tank 12 is a tank that stores a cleaning liquid CL, and a substrate W, such as a semiconductor wafer, which is a workpiece to be cleaned, is immersed in the cleaning liquid CL.

[0031] 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 for converting an electric 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 electric signal S1 from the oscillator 16, the transducer 14 vibrates, and as a result, the cleaning liquid CL is vibrated.

[0032] In the case of the first embodiment, the vibrator 14 is provided in the transmission tank 24, and vibrates the cleaning liquid CL in the cleaning tank 12 via the transmission tank 24. Specifically, a vibration transmission medium ML such as water is stored in the transmission tank 24, and the cleaning tank 12 is placed in the vibration transmission medium ML. That is, 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 transmission tank 24.

[0033] The oscillator 16 is a device that outputs an electric signal (voltage signal) S1 to the transducer 14 (the piezoelectric body 22 thereof) to ultrasonically vibrate the transducer 14. The oscillator 16 will be described in further detail later.

[0034] The control device 18 is a device that outputs an electric signal (control signal) S2 to the oscillator 16, thereby causing 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 the electric signal S2 to the oscillator 16, 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.

[0035] Furthermore, in the case of the first embodiment, the substrate processing apparatus 10 includes a sound pressure sensor 30 that is immersed in the cleaning liquid CL in the cleaning tank 12 and detects the sound pressure (ie, vibration) of the cleaning liquid CL.

[0036] In this embodiment 1, the sound pressure sensor 30 includes a sensor housing 32 that is immersed in 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.

[0037] 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 vibration of the cleaning liquid CL via the sensor housing 32. That is, the piezoelectric body 34 receives the vibration of the sensor housing 32 which is vibrated by the cleaning liquid CL. The piezoelectric body 34 converts the received ultrasonic vibration into an electric signal (voltage signal) S3 and outputs it. The electric signal S3 of the piezoelectric body 34 is finally output to the control device 18 and an oscilloscope 36.

[0038] The sensor housing 32 of the sound pressure sensor 30 is made of a metal material, such as SUS, that is not easily corroded by the cleaning liquid CL. In the case of the first embodiment, the sensor housing 32 is fixed in the cleaning tank 12 so as to be immersed in the cleaning liquid CL and in a vibrating state. The position in the cleaning tank 12 where the sound pressure sensor 30 is disposed 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 is blocked by the sound pressure sensor 30 and cannot be sufficiently transmitted to the substrate W.

[0039] The oscilloscope 36 displays the waveform of the electric 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, thereby allowing an operator of the substrate processing apparatus 10 to monitor the ultrasonic vibration waveform.

[0040] In the case of the present embodiment 1, the control device 18 is configured to execute 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 outputs the corresponding electrical signal S3 when a predetermined electrical signal S2 is input from the control device 18 to the oscillator 16.

[0041] FIG. 2 is a block diagram showing a control system in the substrate processing apparatus according to the first embodiment.

[0042] 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 storage unit 46 that stores the acquired vibration waveform. When the control device 18 is configured with a CPU and the storage unit 46, the CPU operates according to a program stored in the storage unit 46, so that the CPU functions as the oscillator control unit 40, the vibration waveform acquisition unit 42, and the transducer / oscillator state determination unit 44.

[0043] When executing state determination of the vibrator 14 and the oscillator 16, the oscillator control unit 40 outputs a corresponding state stabilization electric signal Sc to the oscillator 16 so that the vibrator 14 oscillates at a state determination frequency fc. This state determination frequency fc will be described later.

[0044] The oscillator control section 40 may be a dedicated control section that controls the oscillator only when the state determination is performed, or may be a control section that controls the oscillator when the substrate W is cleaned.

[0045] 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 in the storage unit 46 as data.

[0046] The vibrator / oscillator state determination unit 44 determines the states 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 storage unit 46 with the newly acquired vibration waveform, and performs state determination based on the comparison result. For example, when the frequency deviation exceeds a predetermined deviation amount and / or the amplitude change amount 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. Then, the occurrence of the abnormality is notified to the operator via the output device 50.

[0047] In order for the transducer / oscillator state determination unit 44 to perform state determination with a high degree of reliability, the sound pressure sensor 30 needs to detect the vibration of the cleaning liquid CL with high sensitivity under predetermined conditions. To this end, in the case of the first embodiment, firstly, the resonant frequency band of the transducer 14 and the resonant frequency band of the piezoelectric body 34 of the sound pressure sensor 30 include a common frequency band.

[0048] FIG. 3 is a diagram showing the relationship between the resonant frequency bands of the vibrator, the sensor housing, and the piezoelectric body of the sound pressure sensor in the first embodiment.

[0049] 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).

[0050] The "resonant frequency band" of the vibrator 14 referred to here is a frequency band in which the vibrator 14 is displaced / deformed more than in other frequency bands when the electric signal S1 to the vibrator 14 is changed. The resonant frequency band of the vibrator 14 differs 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 a desired band by appropriately adjusting these.

[0051] Moreover, the "resonant frequency band" of the piezoelectric body 34 of the sound pressure sensor 30 referred to here means a frequency band in which the sensitivity of the piezoelectric body 34 increases significantly compared to other frequency bands when the frequency of the vibration received by the piezoelectric body 34 is changed, for example, the amplitude of the output signal (voltage signal) increases significantly. The resonant frequency band of the piezoelectric body 34 differs depending on, for example, the material, shape, rigidity, etc. of the piezoelectric body 34, and can be adjusted to a desired band by appropriately adjusting these.

[0052] The oscillator 16 outputs an electric 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 the case where the transducer 14 vibrates at a frequency outside the resonant frequency band). The piezoelectric body 34 that receives the ultrasonic vibrations also resonates and increases its sensitivity, i.e., outputs a voltage signal with a large amplitude (compared to the case where the piezoelectric body 34 receives vibrations of 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.

[0053] Therefore, the vibrator / oscillator state determination unit 44 can determine the states of the vibrator 14 and the 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).

[0054] Figure 4 shows (a) an example of a voltage waveform of a piezoelectric body of a sound pressure sensor when the vibrator vibrates at a frequency within the common frequency band, and (b) 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. In the case of Figure 4(a), one scale on the vertical axis showing voltage represents 50V, and in the case of Figure 4(b), one scale represents 1V.

[0055] 4, when the vibrator 14 vibrates at a frequency (state determination frequency fc) within the common frequency band CB (case (a)), the piezoelectric element 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 vibrate (case (b)). Based on such a voltage signal with a high S / N ratio and large amplitude, it becomes possible to determine the states of the vibrator 14 and the oscillator 16 with high reliability.

[0056] Furthermore, in the case of the first embodiment, the resonant frequency bands of the sensor housings 32 of the sound pressure sensors 30 include the common frequency band CB, as shown in FIG.

[0057] The "resonant frequency band" of the sensor housing 32 referred to here refers to a 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 differs depending on, for example, the material, shape, rigidity, etc. of the sensor housing 32, and can be adjusted to a desired band by appropriately adjusting these.

[0058] According to such a sensor housing 32, the ultrasonic vibration of the state determination frequency fc from the transducer 14 is 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.

[0059] In addition, the state determination frequency ft for determining the state of the vibrator 14 and the oscillator 16 is preferably a frequency during cleaning.

[0060] Specifically, the frequency of ultrasonic vibration (cleaning frequency required for cleaning process) may be included in the cleaning conditions for the substrate W immersed in the cleaning liquid CL. For example, depending on the type of substrate, a frequency in the band of 20 to 300 kHz, or a frequency of 700 kHz or more 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. Since the state determination frequency fc is the cleaning frequency, it becomes possible to determine the state of the transducer 14 and the oscillator 16 while the substrate W is being cleaned. Furthermore, by this determination, it is possible to guarantee that the state of the transducer 14 and the oscillator 16 is in a state in which the substrate W can be cleaned.

[0061] The timing for determining the states of the transducer 14 and the oscillator 16 is not limited to the timing when the substrate W is immersed in the cleaning liquid CL in the cleaning tank 12.

[0062] FIG. 5 shows the substrate not immersed in the cleaning solution in the cleaning tank.

[0063] 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, without being affected by a shift in the immersion position of the substrate W.

[0064] Furthermore, the medium for vibration detection by the sound pressure sensor 30 is not limited to the cleaning liquid CL in the cleaning tank 12.

[0065] FIG. 6 shows a substrate processing apparatus according to an improved embodiment of the first embodiment.

[0066] 6, the sound pressure sensor 30 may be provided in the propagation tank 24 instead of in the cleaning tank 12 to detect the vibration of the vibration transmission medium ML. Even in this case, the states of the vibrator 14 and the oscillator 16 can be determined in the same way as in the case of detecting the vibration of the cleaning liquid CL in the cleaning tank 12. In this case, the states of the vibrator 14 and the oscillator 16 can be determined regardless of whether the substrate W is immersed in the cleaning liquid CL or not, that is, under the same conditions.

[0067] According to the first embodiment as described above, in a substrate processing apparatus including an oscillator that vibrates a cleaning liquid used to clean a substrate and an oscillator that outputs an electrical signal to the oscillator, it is possible to detect vibrations of the cleaning liquid or the vibration transmission medium with high sensitivity.

[0068] (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.

[0069] Fig. 7 is a schematic diagram of a substrate processing apparatus according to a second embodiment of the present invention, and Fig. 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.

[0070] 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 immersed in the cleaning liquid CL, a piezoelectric body 134 disposed therein for converting vibrations into an electrical signal, and electrodes and wiring (not shown) for drawing out the voltage generated by the piezoelectric body 134.

[0071] 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. 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 why 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.

[0072] 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, the quartz cover layer 132b may crack when subjected to vibrations of the state determination frequency ft included in the common frequency band CB.

[0073] The double structure of the sensor housing of the sound pressure sensor may be configured in a manner other than that consisting of a metal housing and a quartz cover layer formed on the outer surface of the housing.

[0074] FIG. 9 shows a substrate processing apparatus according to an improved embodiment of the second embodiment.

[0075] 9, in a substrate processing apparatus 210 according to an improved version of the second embodiment, a sensor housing 232 of a sound pressure sensor 230 is composed of a metal inner housing 232a that houses a piezoelectric body 234, and a cup-shaped quartz outer housing 232b 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.

[0076] As in the above-mentioned embodiment 1, the present embodiment 2 as well can detect the vibration of the cleaning liquid with high sensitivity in a substrate processing apparatus including a vibrator that vibrates the cleaning liquid used to clean the substrate and an oscillator that outputs an electrical signal to the vibrator.

[0077] Also 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 propagation medium ML.

[0078] Although the present invention has been described above with reference to the above-mentioned first and second embodiments, the embodiments of the present invention are not limited to the above-mentioned embodiments.

[0079] 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.

[0080] 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.

[0081] In the above-mentioned first and second embodiments, 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, as shown in Fig. 1 and Fig. 7. However, the embodiments of the present invention are 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.

[0082] Furthermore, in the case of the above-mentioned first embodiment, 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, one sound pressure sensor can be shared by a plurality of substrate processing apparatuses.

[0083] When the sound pressure sensor is detachable from the substrate processing apparatus, the sound pressure sensor may include a plurality of different piezoelectric elements.

[0084] FIG. 10 is a schematic view of a substrate processing apparatus according to another embodiment of the present invention.

[0085] 10, in a substrate processing apparatus 310 according to another embodiment, a sound pressure sensor 330 detachably attached to the cleaning tank 12 includes three piezoelectric bodies 324A, 324B, and 324C in a sensor housing 332. The three piezoelectric bodies 324A, 324B, and 324C each have 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 transducer. This improves the versatility of the sound pressure sensor.

[0086] Furthermore, in the case of the above-mentioned embodiment 1, as shown in Fig. 1, the oscillator 14 is provided in the propagation tank 24. That is, the cleaning liquid CL is vibrated by the oscillator 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.

[0087] FIG. 11 is a schematic view of a substrate processing apparatus according to still another embodiment of the present invention.

[0088] 11, a substrate processing apparatus 410 according to yet another embodiment does not include a propagation tank, unlike the first embodiment. Therefore, the vibrator 14 is provided in the cleaning tank 12. The sound pressure sensor 30 is also provided in the cleaning tank 12. According to such a substrate processing apparatus 410, the loss of vibration transmitted from the vibrator 14 to the cleaning liquid CL is reduced compared to the case where a propagation tank is provided.

[0089] That is, a substrate processing apparatus according to one embodiment of the present invention, in a broad sense, is an apparatus having a cleaning tank for storing a cleaning liquid in which a substrate is immersed, a vibrator for vibrating the cleaning liquid, an oscillator for outputting an electrical signal to the vibrator to vibrate the vibrator, and a sound pressure sensor for being immersed in a medium vibrated by the vibrator and detecting the vibration of the medium, wherein the sound pressure sensor includes a piezoelectric body for converting 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 for vibrating the vibrator at a frequency included in the common frequency band.

[0090] In addition, a substrate processing apparatus according to another embodiment of the present invention is, in a broad sense, an apparatus having 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, wherein the sound pressure sensor includes a sensor housing that is immersed in the medium, and a piezoelectric body that is contained within the sensor housing and converts the vibration of the sensor housing into an electrical signal, wherein 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.

[0091] As described above, the above-mentioned embodiment has been described as an example of the technology of the present invention. For this purpose, the drawings and detailed description are provided. Therefore, among the components described in the drawings and detailed description, not only components essential for solving the problem but also components that are not essential for solving the problem in order to exemplify the above-mentioned technology may be included. Therefore, the fact that these non-essential components are described in the drawings or detailed description should not be used to immediately determine that these non-essential components are essential.

[0092] Furthermore, since the above-described embodiment is intended to illustrate the technology of the present invention, various modifications, substitutions, additions, omissions, and the like can be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0093] The present invention can be applied to a cleaning processing apparatus such as a substrate processing apparatus that includes a vibrator and an oscillator that outputs an electric signal to the vibrator to vibrate it. [Explanation of symbols]

[0094] 10 Substrate processing equipment 12 Cleaning tank 14 Transducer 16 Oscillators 30 Sound pressure sensor 34 Piezoelectric CL cleaning solution W substrate

Claims

1. 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.

2. A substrate processing apparatus as described in claim 1, wherein the common frequency band is included in the resonant frequency band of the piezoelectric body.

3. The substrate processing apparatus according to claim 1 , wherein the sensor housing is made of metal and covered with quartz.

4. 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.

5. 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.

6. The substrate processing apparatus according to claim 1 , wherein the medium is a cleaning liquid stored in the cleaning tank.

7. 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.

8. A sound pressure sensor as described in claim 7, wherein a frequency band that is common to the resonant frequency band of the sensor housing and the resonant frequency band of the vibrator is included in the resonant frequency band of the piezoelectric body of the sound pressure sensor.

9. A sound pressure sensor as described in claim 7 or 8, wherein the piezoelectric elements of the sound pressure sensor include a plurality of piezoelectric elements having different resonant frequency bands.

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