JP5780890B2 - Ultrasonic cleaning method and apparatus - Google Patents

Description

  The present invention relates to an apparatus and method for cleaning a semiconductor wafer or glass substrate, and more particularly to an ultrasonic cleaning method and apparatus suitable for cleaning a semiconductor wafer or glass substrate while applying ultrasonic vibration.

  Cleaning methods in the manufacturing process of a semiconductor integrated device are roughly classified into batch cleaning and single wafer cleaning. Batch cleaning is a cleaning method in which a plurality of objects to be cleaned are simultaneously immersed in a processing tank in which a cleaning liquid is stored. On the other hand, single-wafer cleaning is a cleaning method in which a cleaning liquid is applied to an object to be cleaned and processed one by one. In any of the methods, irradiation of ultrasonic vibration to the cleaning liquid is used in combination to reduce the amount of water and chemicals used as the cleaning liquid.

  As a conventional ultrasonic cleaning apparatus, for example, in Japanese Patent Application Laid-Open No. 2003-320328 (Patent Document 1), a frequency of 500 KHz or more is set in a state where an object to be cleaned is immersed in a cleaning liquid filled in a cleaning tank. Ultrasonic cleaning device that performs uniform and stable cleaning by oscillating the cleaning tank by applying amplitude modulation or frequency modulation at a low frequency including the liquid, and moving the stagnant area generated in a part of the cleaning tank Is described.

  JP 2008-227300 A (Patent Document 2) has a cleaning tank having a double structure of an inner tank and an outer tank, and the bottom of the inner tank is attached in a state of being inclined with respect to the bottom of the outer tank, Washing with uniform sound pressure in the entire region of the washing tank by applying ultrasonic vibrations with different modulation widths from the two frequency modulators with a single frequency as the center frequency while supplying the washing liquid to each tank The structure to be described is described.

  Furthermore, in Japanese Patent Application Laid-Open No. 2007-268448 (Patent Document 3), an ultrasonic vibrator of an ultrasonic cleaning device is formed with a composite element arrangement structure in which a plurality of ultrasonic vibrators are arranged and bonded on a diaphragm, The document describes that uniform precision cleaning can always be performed on an object to be cleaned by suppressing a difference in thickness of each vibration part of the diaphragm.

JP 2003-320328 A JP 2008-227300 A JP 2007-268448 A

  As described in Patent Documents 1 to 3, the conventional general batch type ultrasonic cleaning apparatus cleans the ultrasonic vibration generated by the ultrasonic vibration generating unit in a state where the cleaning treatment tank is filled with the cleaning liquid. The object to be processed immersed in the cleaning liquid is cleaned in the cleaning tank by being transmitted to the cleaning liquid inside the processing tank.

  At this time, by transmitting ultrasonic vibration to the cleaning liquid inside the cleaning treatment tank, a cavity (cavity) in a decompressed state is locally generated in the cleaning liquid. Further, the cavity part immediately takes in the dissolved gas in the cleaning liquid around the cavity part into the cavity part to form minute bubbles (cavitation bubbles). The cavitation bubbles perform complicated movements such as translation, expansion / contraction and collapse due to a pressure difference generated in the cleaning liquid irradiated with vibration. When these movements occur near the surface of the object to be cleaned immersed in the cleaning liquid inside the cleaning tank, particulate dust or film adhered to the surface of the object to be cleaned due to the strong liquid flow of the cleaning liquid that accompanies the movement. The dust is peeled off.

  At this time, if the ultrasonic vibration transmitted to the cleaning liquid inside the cleaning treatment tank is biased and the ultrasonic vibration is concentrated in part, or the generated ultrasonic vibration matches the resonance frequency of the object to be processed. It is assumed that damage (breakage) occurs in the workpiece.

  On the other hand, Patent Documents 1 to 3 all describe that cleaning is performed with uniform and stable ultrasonic vibration in the entire area of the cleaning tank, but the drive frequency is set to the resonance frequency of the object to be processed. There is no description about homogenization in the tank so as not to coincide with.

  Accordingly, the present invention provides an ultrasonic cleaning method and apparatus for solving the above-described problems of the prior art, suppressing damage occurring in a local portion of the surface of the object to be cleaned, and obtaining stable cleaning performance. Objective.

In order to solve the above-mentioned problems, in the present invention, a processing tank for storing a cleaning liquid, a holding means for holding an object to be cleaned immersed in the cleaning liquid inside the processing tank for storing the cleaning liquid, and ultrasonic vibration An ultrasonic vibration generating unit to be generated, an oscillator for generating ultrasonic vibrations by applying high frequency power within a certain range in the ultrasonic vibration generating unit, and an ultrasonic vibration generated by the ultrasonic vibration generating unit Vibration transmitted to the cleaning liquid contained in the cleaning liquid, and vibration generated in the object to be cleaned that is held in the holding means and immersed in the cleaning liquid inside the treatment tank by the ultrasonic vibration transmitted to the cleaning liquid by the vibration transmitting section In the ultrasonic cleaning apparatus including the vibration detection unit that detects the vibration and the control unit that receives the signal detected by the vibration detection unit and controls the oscillator, the control unit has high-frequency power applied to the ultrasonic vibration generation unit Model In a band of frequencies, and arranged to control said oscillator to reduce the high-frequency power of a frequency band corresponding to the resonance frequency band of the object to be cleaned with respect to the high frequency power of the other frequency bands.

In order to achieve the above object, the present invention, the object to be cleaned inside of the processing tank containing a washing liquid and held immersed in the cleaning liquid, by changing the frequency range of the ultrasonic vibration Oscillator The generated high-frequency power is applied to the ultrasonic vibration generating unit to generate ultrasonic vibration, and the generated ultrasonic vibration is propagated to the cleaning liquid in which the object to be cleaned is immersed in the processing tank. the in ultrasonic cleaning method of ultrasonic cleaning, it corresponds to the resonance frequency band of the object to be cleaned out of the high-frequency power which is generated by changing the frequency range to be applied from the ultrasonic vibration Oscillator ultrasonic vibration generating unit The high frequency power of the frequency band to be applied is reduced with respect to the high frequency power of other frequency bands and applied to the ultrasonic vibration generating unit.

  According to the present invention, it is possible to suppress a phenomenon in which a high sound pressure is instantaneously applied to a local portion of the surface of the object to be cleaned due to strong vibration of the object to be cleaned. Thereby, it is possible to provide an ultrasonic cleaning apparatus capable of suppressing damage (breakage) in the local portion and obtaining stable cleaning performance. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a block diagram illustrating a configuration of an ultrasonic cleaning device in Embodiment 1. FIG. FIG. 3 is a block diagram illustrating a configuration of an ultrasonic vibration generation unit according to the first embodiment. FIG. 3 is a front cross-sectional view illustrating a configuration of a vibration transmission unit according to the first embodiment. 2 is a front cross-sectional view illustrating a configuration of a cleaning processing unit in Embodiment 1. FIG. FIG. 3 is a block diagram illustrating a configuration of a vibration detection unit and a transport mechanism in Embodiment 1. FIG. 3 is a block diagram illustrating a configuration of a control unit according to the first embodiment. 3 is a flowchart illustrating processing of a control unit according to the first embodiment. It is a voltage waveform figure of the high frequency electric power in Example 1, and is a graph which shows a state with an initial voltage amplitude constant. 2 is an example of a graph showing a frequency waveform of high-frequency power in Example 1. 3 is a graph showing a change with time of vibration intensity in an object to be cleaned in Example 1. It is an example of the data which a calculating part calculates in Example 1, and is a graph which shows the relationship between the frequency and voltage amplitude before adjusting the voltage amplitude in a resonant frequency band. It is an example of the data which a calculating part calculates in Example 1, and is a graph which shows the relationship between the frequency and voltage amplitude after adjusting the voltage amplitude in a resonant frequency band. It is a voltage waveform figure of the high frequency electric power in Example 1, and is a graph which shows the state which adjusted the voltage amplitude in a resonant frequency band. FIG. 6 is an applied voltage waveform diagram showing a state in which a voltage application duty ratio D (T ₀ / T) is D _{0 in} a resonance frequency band. FIG. 6 is an applied voltage waveform diagram showing a state in which a voltage application duty ratio D (T ₁ / T) is D _{1 in} a resonance frequency band. FIG. 6 is an applied voltage waveform diagram showing a state in which a voltage application duty ratio D (T ₂ / T) is D _{2 in} a resonance frequency band. FIG. 5 is a block diagram illustrating a configuration of an ultrasonic cleaning device in Embodiment 2. It is a block diagram which shows the structure of the vibration detection part in Example 2. FIG. 6 is a graph showing changes over time in vibration intensity in an object to be cleaned in Example 2. FIG. 6 is a block diagram illustrating a configuration of an ultrasonic cleaning device in Embodiment 3. FIG. 6 is a front cross-sectional view illustrating a configuration of an ultrasonic vibration generating unit according to a third embodiment. FIG. 6 is a front cross-sectional view illustrating a configuration of a cleaning processing unit in Example 3. FIG. 9 is a block diagram illustrating a configuration of a vibration detection unit and a transport mechanism in Embodiment 3. FIG. 10 is a block diagram illustrating a configuration of an ultrasonic cleaning device according to a fourth embodiment. It is a block diagram which shows the structure of the ultrasonic vibration generation part in Example 4, and a vibration detection part. FIG. 10 is a block diagram illustrating a configuration of an ultrasonic cleaning device according to a fifth embodiment. FIG. 10 is a block diagram illustrating a configuration of a vibration detection unit according to a fifth embodiment.

  Embodiments will be described below with reference to the drawings.

  In this embodiment, an example of a batch type ultrasonic cleaning apparatus using a method of directly detecting vibration of an object to be cleaned using a piezoelectric element will be described.

  FIG. 1 is an example of a configuration diagram of an ultrasonic cleaning apparatus 100 according to the first embodiment. The ultrasonic cleaning apparatus 100 includes an oscillator 110, an ultrasonic vibration generation unit 120, a vibration transmission unit 130, a cleaning processing unit 140, a vibration detection unit 150, and a control unit 160.

  The oscillator 110 applies an electrical signal (high frequency power) having a frequency of 20 kHz or more and a predetermined amplitude to the ultrasonic vibration generating unit 120. In the case where a delicate structure such as a wiring pattern is formed on the surface of the object to be cleaned W, the frequency is preferably 500 kHz or more in order to suppress the destruction of the fine structure.

  FIG. 2 is an example of a configuration diagram of the ultrasonic vibration generator 120. The ultrasonic vibration generator 120 includes a piezoelectric vibrator 121, a diaphragm 122, a vibrator case 123, and power supply cables 124a and 124b.

  The piezoelectric vibrator 121 is a plate-like sintered body of zircon lead titanate (PZT), and its main surface (surface facing the vibration plate 122) is rectangular. The piezoelectric vibrators 121 are arranged in an array, the main surface side is bonded to the back surface of the diaphragm 122, and the opposite side of the main surface is shielded from the outside by the vibrator case 123. A ground electrode layer 121a is formed on the main surface side of the piezoelectric vibrator 121, and a high-frequency applying electrode layer 121b is formed on the surface opposite to the main surface. The power supply cable 124a has one end connected to the oscillator 110 and the other end connected to the ground electrode layer 121a. The power supply cable 124b has one end connected to the oscillator 110 and the other end connected to the high-frequency applying electrode layer 121b.

  When high frequency power is applied from the oscillator 110 via the power supply cables 124a and 124b, the ground electrode layer 121a, and the high frequency application electrode layer 121b, the piezoelectric vibrator 121 expands and contracts in the thickness direction due to the inverse piezoelectric effect. The vibration propagates to the diaphragm 122 and is emitted as ultrasonic vibration from the main surface of the diaphragm 122 toward the vibration transmission unit 130.

  FIG. 3 is an example of a configuration diagram of the vibration transmission unit 130. The vibration transmission unit 130 includes deaerated water 131 and an indirect tank 132 that stores the deaerated water 131. 133 a is a supply port for supplying the deaerated water 131 to the indirect tank 132, and 133 b is an outlet for discharging the deaerated water 131 from the indirect tank 132. An opening 132a is provided at the bottom of the indirect tank 132, and the diaphragm 122 is attached to the opening 132a. The ultrasonic vibration radiated from the surface of the diaphragm 122 propagates to the cleaning processing unit 140 via the deaerated water 131. Therefore, it is desirable that the inside of the indirect tank 132 does not include an obstacle, gas, or the like that hinders propagation of ultrasonic vibration as in the present embodiment.

  FIG. 4 is an example of a configuration diagram of the cleaning processing unit 140. The cleaning processing unit 140 includes a processing tank 141 and a transport mechanism 142, and any material is quartz.

  The processing tank 141 is a tank having a square section when viewed from the bottom, and includes a supply pipe 141a for the cleaning liquid L near the bottom, and an outer tank 141b on the upper outer wall surface of the processing tank 141. An opening is locally provided at the bottom of the outer tank 141b, and a waste liquid pipe 141c is attached to the opening. The cleaning liquid L is supplied through the liquid supply pipe 141 a and stored in the processing tank 141. The cleaning liquid L overflowing from the processing tank 141 is temporarily stored in the outer tank 141b and discharged out of the system through the waste liquid pipe 141c. Note that the cleaning liquid L is preferably a solution having a dissolved gas concentration adjusted. The ultrasonic vibration radiated through the vibration transmitting unit 130 is propagated to the cleaning liquid L through the bottom of the treatment tank 141, so that a cleaning effect on the object to be cleaned W appears.

  FIG. 5 is an example of a configuration diagram of the vibration detection unit 150 and an example of a configuration diagram of the transport mechanism 142. The vibration detection unit 150 includes a piezoelectric element 151, an amplifier 152, and a waveform measuring instrument 153. The transport mechanism 142 includes a lifter 142a and a holding unit 142b, and is integrated with the piezoelectric element 151.

  The lifter 142 a adjusts the position of the object to be cleaned W together with the holding part 142 b inside the processing tank 141. A plurality of holding grooves 142c are carved in the holding part 142b, and the piezoelectric element 151 is installed on the surface of at least one holding groove 142c. The object to be cleaned W comes into contact with the main surface of the piezoelectric element 151 when the holding groove sandwiches a part of the outer peripheral portion of the object to be cleaned W. The cable 151a connected to the piezoelectric element 151 at one end is embedded in the lifter 142a and the holding portion 142b so as not to be exposed inside the processing bath 141. The other end of the cable 151 a is connected to an amplifier 152 installed outside the cleaning processing unit 140.

  When detecting the vibration (Lamb wave) of the cleaning object W, the piezoelectric element 151 converts it into a voltage signal by the piezo effect. The amplifier 152 amplifies the voltage signal, and the waveform measuring instrument 153 measures the amplified voltage signal and displays the measured signal waveform on the display screen 154.

  FIG. 6 is an example of a configuration diagram of the control unit 160. The control unit 160 includes an external communication unit 161, an oscillator monitor 162, a vibration detection unit monitor 163, a recording unit 164, and a calculation unit 165.

  FIG. 7 is a flowchart for explaining a series of operations performed by the ultrasonic cleaning apparatus 100. First, as an initial stage process, the external communication unit 161 receives an input of a cleaning process start from the outside of the ultrasonic cleaning apparatus 100 (S701), starts generation of high frequency power to the oscillator 110 (S702), and vibrates. The detection unit 150 is caused to start vibration detection (S703). The oscillator 110 receives an input from the external communication unit 161, and generates high-frequency power having a constant voltage amplitude, a constant frequency modulation range, and a constant frequency modulation period (start of a cleaning process). The oscillator monitor 162 receives the elapsed time from the start of the cleaning process and the frequency of the high-frequency power as inputs, and stores them in the recording unit 164 as changes in the frequency with time (S704). The vibration detection unit monitor 163 receives the elapsed time from the start of the cleaning process and the vibration intensity quantified by the waveform measuring instrument 153 as inputs, and stores them in the recording unit 164 as changes in vibration intensity over time (S705).

FIG. 8 shows an example of a voltage waveform 801 of high frequency power generated by the oscillator 110 in the initial stage. The horizontal axis 811 in the figure is the elapsed time t from the start of the cleaning process, and the vertical axis 812 in the figure is the voltage V. Although the voltage amplitude V ₀ is constant, the time until the phase returns to the original value (the reciprocal of the frequency f) varies with the elapsed time. The voltage V is given by equation (1).

FIG. 9 is an example of a frequency waveform 901 of high-frequency power generated by the oscillator 110 in the initial stage, and is data received by the oscillator monitor 162 as input and stored in the recording unit 164. The horizontal axis 911 in the figure is the elapsed time t from the start of the cleaning process, and the vertical axis 912 in the figure is the frequency f. The frequency modulation range f ₀ −Δf to f ₀ + Δf and the frequency modulation period τ are both constant. The frequency f is given by equation (2).

  FIG. 10 is an example of the change over time of the vibration intensity 1001 of the cleaning object W in the initial stage, and is data received by the vibration detection unit monitor 163 as input and stored in the recording unit 164. The horizontal axis 1011 in the figure is the elapsed time t from the start of the cleaning process, and the vertical axis 1012 in the figure is the voltage signal v obtained by vibration intensity conversion and amplification. A state where the amplitude | v | of the voltage signal v having the vibration intensity 1001 is large, that is, a state where the vibration of the cleaning target W is strong appears periodically.

Returning to the flowchart of FIG. 7, processing after the initial stage has elapsed in the control unit 160 will be described. The recording unit 164 inputs the temporal change data 901 of the frequency f (FIG. 9) and the temporal change data 1001 (FIG. 10) of the vibration intensity voltage signal v to the arithmetic unit 165 (S706). The calculation unit 165 receives the input from the recording unit 164, calculates the amplitude | v | for each frequency f (S707), and the amplitude | v | is the reference range in any frequency modulation range f−Δf to f + Δf. It is diagnosed whether or not v _{min to} v _max are entered (S708).

When the amplitude | v | falls within the reference range, the arithmetic unit 165 instructs the external communication unit 110 to continue the initial stage processing (S704, S705). On the other hand, if the amplitude | v | does not fall within the reference range, the external communication unit 110 is commanded to change the voltage amplitude V ₀ at the frequency f at that time (S709). The content of the instruction is to increase V ₀ if | v | <v _min and decrease V ₀ if | v |> v _max .

The external communication unit 161 receives the input from the calculation unit 165 and resets the voltage amplitude V ₀ of the high frequency power at each frequency f to the oscillator 110. In any frequency modulation range f−Δf to f + Δf, the calculation unit 165 repeatedly resets the voltage amplitude V ₀ until the amplitude | v | falls within the reference range. The oscillator monitor 162, the vibration detection unit monitor 163, and the recording unit 164 continue the respective processes regardless of whether or not the amplitude | v | falls within the reference range.

FIG. 11A is an example of data calculated by the calculation unit 165. The horizontal axis 1111 in the figure is the frequency f, and the vertical axis 1112 in the figure is the amplitude | v | of the vibration intensity voltage signal v1101. In the case of this figure, when the initial voltage amplitude V ₀ is constant, the amplitudes | v |> v _max at the frequencies f _{0a to} f _0b , the frequencies f _{1a to} f _1b, and the frequencies f _{2a to} f _2b . The frequency range is defined as a resonance frequency band.

In this case, the arithmetic unit 165 resets the voltage amplitude in each resonance frequency band to V ₀₀ , V ₀₁ and V ₀₂ (in FIG. 12, the voltage amplitude in the range of frequencies f _{1a to} f _1b is set to V ₀₁ . As shown in FIG. 11B as a waveform 1102, the amplitude | v |, that is, the object to be cleaned is obtained at the frequencies f _{0a to} f _0b , the frequencies f _{1a to} f _1b, and the frequencies f _{2a to} f _2b . The vibration of the object W is reduced. As a result, a phenomenon in which a high sound pressure is instantaneously applied to a local portion on the surface of the object to be cleaned W is prevented, and damage (breakage) is suppressed. In each resonance frequency band, instead of resetting the voltage amplitude V ₀ , the voltage application duty ratio D (T _i / T) is D ₀ as shown in FIG. 13A and D ₁ as shown in FIG. 13B. and the same effect can be obtained by resetting the D ₂ as shown in FIG. 13C.

  Returning to the flowchart of FIG. 7, in the final stage processing in the control unit 160, the external communication unit 161 checks whether or not there is an input to stop the cleaning process from the outside of the ultrasonic cleaning apparatus 100 (S710). . As a result, when there is no stop input (in the case of NO), the process returns to the steps of S704 and S705 to continue the series of processes. On the other hand, if there is a stop input (in the case of YES), generation of high-frequency power is stopped for the oscillator 110 (S711), and vibration detection is stopped for the vibration detection unit 150 (S712). The oscillator monitor 162 stops in response to the stop of high-frequency power generation in the oscillator 110 (S713), and the vibration detector monitor 163 stops in response to the vibration detection stop in the vibration detector 150 (S714). The recording unit 164 stops when at least one of the oscillator monitor 162 and the vibration detection unit monitor 163 stops (S715). The calculation unit 165 stops in response to the stop of the recording unit 164 (S716). As a result, the series of operations is completed.

  In this embodiment, an example of a batch type ultrasonic cleaning apparatus using a method of indirectly detecting vibration of an object to be cleaned using an optical displacement sensor will be described.

  FIG. 14 is an example of a configuration diagram of the ultrasonic cleaning apparatus 200 according to the second embodiment. The ultrasonic cleaning apparatus 200 includes an oscillator 110, an ultrasonic vibration generation unit 120, a vibration transmission unit 130, a cleaning processing unit 140, a vibration detection unit 250, and a control unit 160.

  In the ultrasonic cleaning apparatus 100 of FIG. 1 described in the first embodiment, the vibration detection unit 150 is changed to the vibration detection unit 250. The other configurations have the same functions as the configurations denoted by the same reference numerals shown in FIGS. 1 to 4 and FIG. 6 described above, and thus description thereof is omitted.

  FIG. 15 is an example of a configuration diagram of the vibration detection unit 250. The vibration detection unit 250 includes a drive circuit 251, a light source 252, a light projection lens 253, a light reception lens 254, an optical position detection element 255, an amplifier 256, and a waveform measuring instrument 257. Note that none of the components of the vibration detection unit 250 is integrated with the transport mechanism 142 and is completely independent.

  The drive circuit 251 supplies power to the light source 252. The light source 252 is a light-emitting diode that has high responsiveness of light emission timing and light emission intensity with respect to the type of input power (DC or AC), frequency, and voltage amplitude. The light projecting lens 253 is disposed outside the surface of the processing tank 141 on the side where one end of the object to be cleaned W faces, condenses the light emitted from the light source 252, and enters the processing tank 141. . The light receiving lens 254 is disposed outside the surface of the processing tank 141 that faces the surface on which the light projection lens 253 is disposed. The light receiving lens 254 collects light that has passed through the processing tank 141 and detects the optical position. Incident on element 255. The optical position detection element 255 converts the intensity of the detected light into a voltage signal at a predetermined coordinate in the element. The amplifier 256 amplifies the voltage signal, and the waveform measuring instrument 257 measures the amplified voltage signal.

  FIG. 16 is an example of the change over time of the vibration intensity 1501 in the object W to be cleaned, and is the change over time in the detected light intensity at coordinates corresponding to the vicinity of the surface of the object W to be cleaned in the optical position detection element 255. The horizontal axis 1511 in the figure is the elapsed time t from the start of the cleaning process, and the vertical axis 1512 in the figure is the voltage signal v obtained by conversion and amplification of the detected light intensity. When the vibration of the object to be cleaned W is strong, the refractive index with respect to the light greatly varies with the density of the cleaning liquid L in the vicinity of the surface of the object to be cleaned W. Therefore, the amplitude | v of the voltage signal v varies. | Increases.

  Even in the case of the present embodiment, the data shown in FIGS. 11A and 11B can be calculated. Therefore, by executing the processing based on the flowchart shown in FIG. 7, a phenomenon in which a high sound pressure is instantaneously applied to a local portion of the surface of the object to be cleaned W is prevented, and damage (breakage) is suppressed. The

  In the present embodiment, an example of a single wafer ultrasonic cleaning apparatus using a method of directly detecting vibration of an object to be cleaned using a piezoelectric element will be described.

  FIG. 17 is an example of a configuration diagram of an ultrasonic cleaning apparatus 300 according to the third embodiment. The ultrasonic cleaning apparatus 300 includes an oscillator 110, an ultrasonic vibration generation unit 320, a cleaning processing unit 340, a vibration detection unit 350, and a control unit 160.

  In the ultrasonic cleaning apparatus 100 of FIG. 1 described in the first embodiment, the ultrasonic vibration generating unit 120 is changed to the ultrasonic vibration generating unit 320, the vibration transmitting unit 130 is omitted, and the cleaning processing unit 140 is replaced with the cleaning processing unit 340. The vibration detection unit 150 is changed to the vibration detection unit 350. The other configuration has the same function as the configuration denoted by the same reference numeral shown in FIG.

  FIG. 18 is a configuration diagram of the ultrasonic vibration generator 320. The ultrasonic vibration generator 320 includes a piezoelectric vibrator 321, a diaphragm 322, a vibrator case 323, and a power supply cable 324, and has a cylindrical appearance as a whole. The ultrasonic vibration generating unit 320 is installed at a distance of 1 mm to 3 mm from the main surface with respect to the object to be cleaned W installed so that the main surface faces upward.

  The piezoelectric vibrator 321 is a plate-like sintered body of zircon lead titanate (PZT), and its main surface is circular and is bonded to the back surface of the vibration plate 322. An electrode layer 321a is formed on the main surface of the piezoelectric vibrator 321 and the opposite surface. The diaphragm 322 is plate-like quartz, and the diameter of the main surface thereof is the same as that of the main surface of the piezoelectric vibrator 321. The vibrator case 323 is a cylindrical fluororesin and includes the piezoelectric vibrator 321, the diaphragm 322, and the power supply cable 324. A circular opening 323 a is provided at the bottom of the vibrator case 323, and the diameter of the opening 323 a is smaller than the diameter of the diaphragm 322. The piezoelectric vibrator 321 and the diaphragm 322 are attached in the vicinity of the opening 323a, and a part of the inside of the main surface of the diaphragm 322 is exposed to the opening 323a. The power supply cable 324 has one end connected to the oscillator 110 and the other end connected to the electrode layer 321a.

  When high frequency power is applied from the oscillator 110 via the power supply cable 324 and the electrode layer 321a, the piezoelectric vibrator 321 expands and contracts in the thickness direction due to the inverse piezo effect, and this vibration propagates to the diaphragm 322. Radiated as ultrasonic vibrations from the main surface of the diaphragm 322.

  FIG. 19 is an example of a configuration diagram of the cleaning processing unit 340. The cleaning processing unit 340 includes liquid supply pipes 341a and 341b, a transport mechanism 342, and a swing arm 343.

  The liquid supply pipes 341a and 341b are circular tubular fluororesins. The liquid supply pipe 341a is arranged in parallel above the main surface of the article W to be cleaned and in the vicinity of the ultrasonic vibration generator 320. The tip of the liquid supply pipe 341a faces the main surface of the object to be cleaned W. The liquid supply pipe 341b is installed below the back surface of the article W to be cleaned. The tip of the liquid supply pipe 341b faces the back surface of the article to be cleaned W. The swing arm 343 simultaneously holds the ultrasonic vibration generating unit 320 and the liquid supply pipe 341a, and swings around the turning shaft 344 as a rotation center in a direction parallel to the main surface of the workpiece W. The cleaning liquid L is discharged from the liquid supply pipe 341a toward the main surface of the object to be cleaned W, and is also discharged from the liquid supply pipe 341b to the back surface of the object to be cleaned W. A liquid film of the cleaning liquid L is formed on the main surface and the back surface of the object to be cleaned W, and the ultrasonic vibration radiated from the main surface of the vibration plate 322 propagates to the cleaning liquid L. And the cleaning effect with respect to the back surface is expressed.

  FIG. 20 is a configuration diagram of the vibration detection unit 350 and a configuration diagram of the transport mechanism 342. The vibration detection unit 350 includes a piezoelectric element 351, an amplifier 352, and a waveform measuring device 353, and the transport mechanism 342 includes a spin base 342a, a holding unit 342b, a rotating shaft 342c, and a motor 342d, and is piezoelectric. It is integrated with the element 351.

  The spin base 342a is located below the back surface of the object to be cleaned W and supports the object to be cleaned W together with the holding portion 342b. At least three holding parts 342b are arranged along the peripheral edge of the upper surface of the spin base 342a, and the piezoelectric elements 351 are installed on the surface of at least one holding part 342b. A part of the outer peripheral portion of the article to be cleaned W is held by the holding portion 342b and simultaneously contacts the main surface of the piezoelectric element 351. The rotating shaft 342c is fixed at one end to the center of the back surface of the spin base 342a and connected to the motor 342d at the other end. When the motor 342d is driven, the rotating shaft 342c rotates and the spin base 342a, the holding portion 342b, and the article W to be cleaned integrally rotate horizontally. The cable 351a connected to the piezoelectric element 351 at one end is embedded in the spin base 342a, the holding portion 342b, and the rotating shaft 342c so as not to be exposed to the cleaning liquid L. The other end of the cable 351a is connected to an amplifier 352 installed outside the cleaning processing unit 340.

  The piezoelectric element 351, the amplifier 352, and the waveform measuring instrument 353 have the same functions as the piezoelectric element 151, the amplifier 152, and the waveform measuring instrument 153 shown in FIG.

  Also in the case of the present embodiment, the data shown in FIGS. 8 to 11B can be calculated. Therefore, by executing the processing based on the flowchart shown in FIG. 7, a phenomenon in which a high sound pressure is instantaneously applied to a local portion of the surface of the object to be cleaned W is prevented, and damage (breakage) is suppressed. The

  In the present embodiment, an example of a single wafer ultrasonic cleaning apparatus in which an ultrasonic vibration generating unit and a vibration detecting unit are integrated will be described.

  FIG. 21 is a configuration diagram of an ultrasonic cleaning apparatus 400 based on the fourth embodiment. The ultrasonic cleaning apparatus 400 includes an oscillator 110, an ultrasonic vibration generation unit 420, a cleaning processing unit 340, a vibration detection unit 450, and a control unit 160.

  In the ultrasonic cleaning apparatus 300 of FIG. 17 described in the third embodiment, the ultrasonic vibration generator 320 is changed to the ultrasonic vibration generator 420 and the vibration detector 350 is changed to the vibration detector 450. Other configurations have the same functions as the configurations denoted by the same reference numerals shown in FIG. 1, FIG. 17 and FIG.

  FIG. 22 is a configuration diagram of the ultrasonic vibration generation unit 420 and a configuration diagram of the vibration detection unit 450. The ultrasonic vibration generator 420 includes a piezoelectric vibrator 321, a diaphragm 322, a vibrator case 323, and a power supply cable 424, and has a cylindrical appearance as a whole. The vibration detection unit 450 includes an amplifier 452 and a waveform measuring instrument 453.

  In the ultrasonic vibration generating unit 320 shown in FIG. 18, the power supply cable 324 is changed to the power supply cable 424, and in the vibration detection unit 350 shown in FIG. 20, the piezoelectric element 351 is omitted.

  The power supply cable 424 includes main cables 424a and 424b, branch cables 424c and 424d, and a relay unit 424e. The main cables 424a and 424b are connected to the oscillator 110 at one end and to the electrode layer 321a of the piezoelectric vibrator 321 at the other end. The branch cables 424c and 424d are connected to the amplifier 452 at one end and are connected to the main cables 424a and 424b in the relay unit 424e at the other end, respectively. The branch cable 424c is used for voltage measurement, and the branch cable 424d is used for current measurement.

The waveform measuring instrument 453 measures changes over time in the voltage and current of the high-frequency power applied by the oscillator 110 to the ultrasonic vibration generating unit 320. When the object to be cleaned W vibrates strongly, the ultrasonic vibration is strongly transmitted to the back surface of the object to be cleaned W, and the irregular reflection phenomenon in the cleaning liquid L becomes remarkable. At this time, the reflected wave component directly incident on the vibration plate 322 from the main surface of the workpiece W is weakened, and the piezoelectric vibrator 321 vibrates strongly with the load reduced. Therefore, the voltage and current measured by the waveform measuring instrument 453 increase. By using the above principle, the waveform measuring device 453 can observe the vibration state of the cleaning object W.

  Also in the case of the present embodiment, the data shown in FIGS. 8 to 11B can be calculated. Therefore, by executing the processing based on the flowchart shown in FIG. 7, a phenomenon in which a high sound pressure is instantaneously applied to a local portion of the surface of the object to be cleaned W is prevented, and damage (breakage) is suppressed. The

  In the present embodiment, an example of a batch type ultrasonic cleaning apparatus using a method of indirectly detecting vibration of an object to be cleaned using a hydrophone probe (sound pressure gauge) will be described.

  FIG. 23 is an example of a configuration diagram of an ultrasonic cleaning apparatus 500 according to the fifth embodiment. The ultrasonic cleaning apparatus 500 includes an oscillator 110, an ultrasonic vibration generation unit 120, a vibration transmission unit 130, a cleaning processing unit 140, a vibration detection unit 550, and a control unit 160.

  In the ultrasonic cleaning apparatus 100 of FIG. 1 described in the first embodiment, the vibration detection unit 150 is changed to the vibration detection unit 550. The other configurations have the same functions as the configurations denoted by the same reference numerals shown in FIGS. 1 to 4 and FIG. 6 described above, and thus description thereof is omitted.

  FIG. 24 is an example of a configuration diagram of the vibration detection unit 550. The vibration detection unit 550 includes a hydrophone probe 551, an amplifier 552, and a waveform measuring device 553.

  The hydrophone probe 551 has a high directivity in the measurement range, and is usually disposed so that the tip 551a faces the ultrasonic vibration generator 120 for the purpose of measuring sound pressure. The hydrophone probe 551 in the present embodiment is disposed in the processing tank 141 so that the tip 551a faces the main surface of the article W to be cleaned. Therefore, a pressure wave radiated from the main surface of the cleaning object W to the cleaning liquid L with the vibration of the cleaning object W is detected with high sensitivity. The hydrophone probe 551 converts a pressure wave into a voltage signal by a piezo effect. The amplifier 552 amplifies the voltage signal, and the waveform measuring device 553 measures the amplified voltage signal and outputs it as a vector quantity having a magnitude and a propagation direction.

  Also in the case of the present embodiment, the data shown in FIGS. 8 to 11B can be calculated. Therefore, by executing the processing based on the flowchart shown in FIG. 7, a phenomenon in which a high sound pressure is instantaneously applied to a local portion of the surface of the object to be cleaned W is prevented, and damage (breakage) is suppressed. The

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be stored in a recording device such as a memory, a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

  Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

  100, 200, 300, 400, 500, 600 ... Ultrasonic cleaning device 110, 610 ... Oscillator 120, 320, 420, 620 ... Ultrasonic vibration generating unit 121, 321 ... Piezoelectric vibrator 130 ... Vibration transmitting unit 132 ... Indirect tank 140, 340, 640 ... cleaning processing unit 141 ... processing tank 141b outer tank 142 ... transport mechanism 150, 250, 350, 450, 550 ... vibration detection unit 151, 351 ... piezoelectric element 152, 352, 552 ... amplifier 153, 353 453, 553 ... Waveform measuring device 160 ... Control unit 161 ... External communication unit 162 ... Oscillator monitor 163 ... Vibration detection unit monitor 164 ... Recording unit 165 ... Calculation unit 251 ... Drive circuit 252 ... Light source 253 ... Projection lens 254 ... Light receiving lens 255: Optical position detection Output element 256 ... Amplifier 257 ... Waveform measuring instrument 551 ... Hydrophone probe.

Claims (8)

A treatment tank containing a cleaning liquid;
Holding means for holding the object to be cleaned immersed in the cleaning liquid inside the treatment tank containing the cleaning liquid;
An ultrasonic vibration generator for generating ultrasonic vibrations;
An oscillator that generates ultrasonic vibrations by applying high-frequency power in a range of frequencies to the ultrasonic vibration generating unit;
A vibration transmission unit configured to transmit the ultrasonic vibration generated by the ultrasonic vibration generation unit to the cleaning liquid stored in the processing tank;
A vibration detection unit that detects vibration generated in the object to be cleaned that is held in the holding unit and immersed in the cleaning liquid inside the processing tank by ultrasonic vibration transmitted to the cleaning liquid by the vibration transmission unit;
An ultrasonic cleaning apparatus comprising a control unit that receives the signal detected by the vibration detection unit and controls the oscillator,
The control unit converts high-frequency power in a frequency band corresponding to a resonance frequency band of the object to be cleaned into high-frequency power in another frequency band in the certain frequency band of the high-frequency power applied to the ultrasonic vibration generating unit. The ultrasonic cleaning apparatus is characterized in that the oscillator is controlled so as to decrease the frequency. An ultrasonic cleaning device according to claim 1, wherein the control unit, a resonance frequency band of the cleaning object from the relationship between the vibration intensity of the vibration detection unit and the frequency at which the Oscillator oscillates detects An ultrasonic cleaning apparatus, wherein the high frequency power applied to the ultrasonic vibration generating unit is reduced with respect to the oscillator in the derived resonance frequency band of the object to be cleaned. 3. The ultrasonic cleaning apparatus according to claim 1, wherein the control unit sets a voltage amplitude of a high frequency power in a frequency band corresponding to a resonance frequency band of the object to be cleaned to a voltage of a high frequency power other than the frequency band. An ultrasonic cleaning apparatus, wherein the oscillator is controlled to decrease with respect to amplitude. 3. The ultrasonic cleaning apparatus according to claim 1, wherein the vibration detection unit includes a piezoelectric element or a projector and a light receiver arranged so as to be in contact with the object to be cleaned. An ultrasonic cleaning apparatus comprising: an optical vibration detecting unit that detects vibration of the object to be cleaned from a signal detected by the light receiver with respect to light irradiated near the surface of the object to be cleaned; or a sound pressure meter . The object to be cleaned is immersed and held in the cleaning liquid inside the treatment tank containing the cleaning liquid,
Internal ultrasonic vibration Oscillator by some the processing bath to ultrasonic vibration frequency power which is generated by varying the frequency applied to the ultrasonic vibration generating unit to generate ultrasonic vibrations were the generated range An ultrasonic cleaning method for ultrasonically cleaning the object to be cleaned by propagating to the cleaning liquid in which the object to be cleaned is immersed,
A high frequency power of a frequency band corresponding to the resonance frequency band of the object to be cleaned out of the high-frequency power which is generated by varying the frequency at the certain range is applied to the ultrasonic vibration generating unit from the ultrasonic vibration Oscillator A method for ultrasonic cleaning, comprising reducing the high frequency power in another frequency band and applying the power to the ultrasonic vibration generator. An ultrasonic cleaning method according to claim 5, the frequency range of the resonance frequency band, the certain the said high-frequency power applied to the ultrasonic vibration generating unit from the ultrasonic vibration Oscillator of the object to be cleaned An ultrasonic cleaning method characterized in that the ultrasonic cleaning method is obtained based on information obtained by detecting a vibration state of the object to be cleaned when the amount is reduced . The ultrasonic cleaning method according to claim 5 or 6, wherein the high frequency power in a frequency band corresponding to a resonance frequency band of the object to be cleaned is changed and applied to the ultrasonic vibration generating unit. An ultrasonic wave characterized in that a voltage amplitude of a high frequency power in a frequency band corresponding to a resonance frequency band of the cleaning object is reduced with respect to a voltage amplitude of a high frequency power other than the frequency band and applied to the ultrasonic vibration generating unit. Cleaning method. The ultrasonic cleaning method according to claim 6, wherein detecting a vibration state of the object to be cleaned is detected by a piezoelectric element arranged so as to be in contact with the object to be cleaned, or a projector and a light receiver And detecting the vibration of the object to be cleaned from the signal detected by the light receiver with the light irradiated to the vicinity of the surface of the object to be cleaned by the projector, or using the sound pressure meter to vibrate the object to be cleaned. An ultrasonic cleaning method characterized by performing any one of detecting pressure waves generated from a cleaning object.

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