JP7513457B2 - Ultrasonic Cleaning Nozzle - Google Patents

Description

The present invention relates to an ultrasonic cleaning nozzle.

For example, Patent Documents 1 and 2 disclose an ultrasonic cleaning nozzle for cleaning an object to be cleaned. This ultrasonic cleaning nozzle sprays cleaning water that has ultrasonic vibrations propagated through it onto the object to be cleaned, and cleans the object by shaking up any dirt adhering to the surface of the object with the ultrasonic vibrations and separating the dirt from the surface. This improves cleaning efficiency.

JP 2013-257583 A JP 2015-202545 A

The object to be cleaned is, for example, a wafer that has been ground using a grinding wheel. Large and small grinding debris generated during grinding are mixed together and adhere to the ground surface of the wafer as dirt. Therefore, when cleaning water that transmits ultrasonic vibrations of one frequency is used, dirt may remain on the cleaned surface (ground surface) of the wafer.

As a countermeasure, it is desirable to clean the wafers using cleaning water that propagates ultrasonic vibrations of at least two different frequencies. For this purpose, it is conceivable to use at least two ultrasonic cleaning nozzles, each equipped with an ultrasonic vibration plate corresponding to at least two different frequencies.

However, in this case, at least two ultrasonic cleaning nozzles must be arranged in the cleaning device, which makes the cleaning device larger.

Therefore, the object of the present invention is to miniaturize a cleaning device that cleans an object by spraying cleaning water through which ultrasonic vibrations of at least two different frequencies are propagated.

The ultrasonic cleaning nozzle of the present invention (the present ultrasonic cleaning nozzle) is an ultrasonic cleaning nozzle that cleans an object by spraying cleaning water through which ultrasonic vibrations are propagated, and comprises a circular ultrasonic vibration plate, a spray port arranged opposite the ultrasonic vibration plate, a case that forms a chamber by supporting the outer peripheral edge of the ultrasonic vibration plate, and a supply port that is formed through the side wall of the case and supplies cleaning water into the chamber, and the ultrasonic vibration plate has at least a first region that ultrasonically vibrates the cleaning water at a first frequency, and a second region that ultrasonically vibrates the cleaning water at a second frequency that is higher than the first frequency, and the first region and the second region are sector-shaped regions whose apex of the central angle is located at the center of the ultrasonic vibration plate .
The first region and the second region may be sector-shaped regions having a central angle of 90 degrees, and the first region and the second region may be formed in pairs so as to be alternately arranged along the circumferential direction of the ultrasonic vibration plate.

In this ultrasonic cleaning nozzle, the ultrasonic vibration plate may be a concave spherical plate with a concave surface facing the nozzle.

The ultrasonic vibration plate may include an annular plate at its outer periphery, the annular plate being supported by the case for amplifying ultrasonic vibrations in the first region and the second region.

This ultrasonic cleaning nozzle propagates ultrasonic vibrations of at least two different frequencies to the cleaning water, and cleans the object to be cleaned with the ultrasonic cleaning water through which ultrasonic vibrations of at least two different frequencies have been propagated. This allows for appropriate removal of dust particles of different sizes adhering to the object to be cleaned. In addition, the ultrasonic vibration plate has a first region that ultrasonically vibrates the cleaning water at a first frequency, and a second region that ultrasonically vibrates the cleaning water at a second frequency higher than the first frequency. Therefore, ultrasonic cleaning water through which ultrasonic vibrations of at least two different frequencies have been propagated can be sprayed from this ultrasonic cleaning nozzle while preventing the ultrasonic cleaning nozzle from becoming too large.

FIG. 1 is a perspective view showing a configuration of an ultrasonic cleaning device. FIG. 1 is an explanatory diagram showing a configuration of an ultrasonic cleaning device. 4 is an explanatory diagram showing the configuration of a dome portion of an ultrasonic vibration plate. FIG. 11A and 11B are explanatory diagrams showing other configurations of the dome portion of the ultrasonic vibration plate. 13 is an explanatory diagram showing still another configuration of the dome portion of the ultrasonic vibration plate. FIG. 11A and 11B are explanatory diagrams showing other configurations of the ultrasonic vibration plate.

Figure 1 is a perspective view showing the configuration of an ultrasonic cleaning device 1 according to this embodiment. The ultrasonic cleaning device 1 cleans a wafer 100 as an object to be cleaned.

The wafer 100 is, for example, a circular, plate-shaped semiconductor wafer made of a silicon base material or the like, and has a substantially flat surface to be cleaned 102. The surface to be cleaned 102 is, for example, a surface that has been ground using a grinding wheel. Therefore, the surface to be cleaned 102 has debris (grinding debris) (not shown) of different sizes and adhesive strengths attached to it.

A surface 101 of the wafer 100 facing downward in FIG. 1 has, for example, a plurality of devices formed thereon and is protected by a protective tape (not shown).
The wafer 100 may be an as-sliced wafer that does not include devices and is cut or peeled from a silicon ingot.

As shown in FIG. 1, the ultrasonic cleaning device 1 includes a holding table 10 that holds the wafer 100, an ultrasonic cleaning nozzle 2, a moving means 4 that moves the ultrasonic cleaning nozzle 2 relative to the wafer 100, and a control unit 70 that controls the operation of the ultrasonic cleaning device 1.

The holding table 10 comprises a circular holding portion 11 and a frame 12 that supports the holding portion 11. The holding portion 11 is a plate made of a porous material, and has a holding surface 13 formed flush with the frame 12. The holding portion 11 is connected to a suction source (not shown), so that the suction force of the suction source is transmitted to the holding surface 13. This allows the holding portion 11 to suction-hold the wafer 100 by means of the holding surface 13.

For example, the wafer 100 may form a work set including a tape with a larger diameter than the wafer 100 attached to the surface 101, and an annular frame attached to the tape. In this case, the holding table 10 may be equipped with, for example, a pendulum-type fixed clamp or a mechanical clamp as a holding part. The holding table 10 may hold the wafer 100 via the annular frame by fixing the annular frame with a holding part that is a type of clamp.

The holding table 10 may be configured to be movable up and down by a lifting means (not shown) such as an air cylinder. The lifting means (not shown) raises the holding table 10 to position it at the height for loading and unloading the wafer 100. The lifting means also lowers the holding table 10 holding the wafer 100 to position it at the height for cleaning work within the casing 14.

The holding table 10 is housed in the internal space of a casing 14 shown in Fig. 1. The casing 14 includes an outer wall 120 surrounding the holding table 10, and a bottom plate 122. The bottom plate 122 is integrally connected to a lower portion of the outer wall 120, and has a through hole (not shown) in the center through which the spindle 41 is inserted.
In FIG. 1, a portion of an outer wall 120 of the casing 14 is cut away to show the inside of the casing 14 .

The casing 14 is supported by a number of legs 124. The upper ends of the legs 124 are fixed to the underside of the bottom plate 122. A drain port (not shown) is formed through the bottom plate 122 in the thickness direction. A member (such as a drain hose) is connected to this drain port for discharging used cleaning water to the outside of the casing 14.

The moving means 4 moves the ultrasonic cleaning nozzle 2 relatively parallel to the surface 102 to be cleaned of the wafer 100 held on the holding table 10. As shown in Figs. 1 and 2, the moving means 4 includes a rotating means 40 that rotates the wafer 100 held on the holding part 11, and a sliding means 44 that moves the ultrasonic cleaning nozzle 2 in the horizontal direction (parallel to the XY plane (surface 102 to be cleaned)).

The rotating means 40 is disposed below the holding table 10. The rotating means 40 rotates the wafer 100 held by the holding part 11 about a rotation axis passing through the center of the holding part 11. The rotating means 40 includes a spindle 41 and a rotation drive source 42 that rotates the spindle 41.

The upper end of the spindle 41 is fixed to the underside of the frame 12 of the holding table 10 and extends in the Z-axis direction. The rotation drive source 42 includes a motor and is connected to the lower end side of the spindle 41. When the rotation drive source 42 rotates the spindle 41, the holding table 10 is rotated, and the wafer 100 held on the holding table 10 is thereby rotated.

The sliding means 44 moves the ultrasonic cleaning nozzle 2 in a horizontal direction, which is a direction that intersects with the rotation direction of the wafer 100 and is parallel to the surface 102 to be cleaned of the wafer 100. In this embodiment, the sliding means 44 is configured to rotate the ultrasonic cleaning nozzle 2 in the horizontal direction.

Specifically, the slide means 44 includes a swivel arm 45 that is inverted L-shaped when viewed from the side, and a swivel motor 46 that is connected to the lower end of the swivel arm 45. The swivel arm 45 is erected on the bottom plate 122 of the casing 14 via a bearing or the like (not shown). The ultrasonic cleaning nozzle 2 is disposed on the tip side of the swivel arm 45. The swivel motor 46 moves the swivel arm 45 in a swivel manner.

The ultrasonic cleaning nozzle 2 cleans the wafer 100 by spraying cleaning water that has ultrasonic vibrations propagated therethrough. As shown in FIG. 2, the ultrasonic cleaning nozzle 2 includes a case 20 that temporarily stores cleaning water 500 supplied from a cleaning water supply source 60, a spray nozzle 241 formed on the underside of the case 20, and a circular ultrasonic vibration plate 3 disposed within the case 20 opposite the spray nozzle 241.

The case 20 is formed, for example, in a substantially cylindrical shape and includes a bottom plate 21, a top plate 22 that faces the bottom plate 21 in the Z-axis direction, and a substantially cylindrical side wall 23 that connects the bottom plate 21 and the top plate 22. A swivel arm 45 shown in FIG. 1 is fixed to the upper surface of the top plate 22.

The inside of the case 20 is divided by the ultrasonic vibration plate 3 into two chambers, an upper chamber 221 above the ultrasonic vibration plate 3, and a second chamber 222 below the ultrasonic vibration plate 3. A water supply port 231 is formed through the side wall 23 of the lower second chamber 222.

The water supply port 231 is used to supply cleaning water 500 to the second chamber 222 between the ultrasonic vibration plate 3 and the injection port 241 in the case 20. This water supply port 231 is connected to the cleaning water supply source 60 via a flexible resin tube or the like. The cleaning water supply source 60 is equipped with a pump or the like and is configured to supply cleaning water 500 such as pure water. The cleaning water 500 supplied from the cleaning water supply source 60 is temporarily stored in the second chamber 222 of the case 20.

The bottom plate 21 is formed with a nozzle portion 24 that protrudes in the -Z direction. The nozzle portion 24 is gradually tapered toward the tip. The nozzle portion 24 is provided with an outlet 241 at its tip, which injects the cleaning water 500 stored in the second chamber 222 of the case 20. The nozzle portion 24 may have a shape that does not taper toward the outlet 241.

In this embodiment, the ultrasonic vibration plate 3 is a circular dome-shaped plate when viewed from above, and is a concave spherical plate with a concave lower surface that faces the injection port 241. The injection port 241 is disposed opposite the ultrasonic vibration plate 3.

The ultrasonic vibration plate 3 is configured to receive high-frequency power and generate ultrasonic vibrations. The ultrasonic vibration plate 3 propagates ultrasonic vibrations 600 to the cleaning water 500 stored in the second chamber 222 of the case 20. The ultrasonic vibration plate 3 is disposed in a position facing the nozzle 241 within the case 20. The ultrasonic vibration plate 3 has an arc-shaped cross section, and the surface facing the nozzle 241 is concave. In other words, the nozzle 241 faces the concave surface of the ultrasonic vibration plate 3.

The ultrasonic vibration plate 3 comprises a dome portion 30 in the form of a concave spherical plate, a flange portion 31 that protrudes radially outward from the outer periphery of the dome portion 30, and an annular plate 32 that protrudes radially outward from the outer periphery of the flange portion 31.

The dome portion 30 is composed of, for example, a piezoelectric element, which is a type of ceramic, and its lower surface 261 forms a concave surface. As shown in FIG. 3, the dome portion 30 includes a second region 36 that is circular when viewed from above and located in the center, and a first region 35 that is thicker than the second region 36 and concentrically surrounds the second region 36. In other words, the ultrasonic vibration plate 3 (dome portion 30) has the first region 35 and the second region 36 that are formed in concentric circles centered on the center of the ultrasonic vibration plate 3 (dome portion 30).

A first central electrode 51 is attached to the first region 35 of the dome portion 30. On the other hand, a plurality of first peripheral electrodes 52 are attached at equal intervals in the circumferential direction to the upper surface side of the flange portion 31 of the ultrasonic vibration plate 3 (only one first peripheral electrode 52 is shown in FIG. 3). A first ultrasonic oscillator 91 is connected to the first central electrode 51 and the first peripheral electrode 52.

The first ultrasonic oscillator 91 includes a high-frequency power source and supplies high-frequency power (high-frequency energy) of a first frequency to the first region 35 of the dome portion 30 via the first central electrode 51 and the first peripheral electrode 52. As a result, the first region 35 of the dome portion 30 is ultrasonically vibrated in its entirety at the first frequency by the first ultrasonic oscillator 91.
In this embodiment, the first frequency is a relatively low frequency, for example, a frequency in the range of 200 kHz to 600 kHz.

On the other hand, a second central electrode 55 is attached to the center of the second region 36 of the dome portion 30. A plurality of second peripheral electrodes 56 are attached at equal intervals in the circumferential direction to the upper surface side of the flange portion 31 of the ultrasonic vibration plate 3 (only one second peripheral electrode 56 is shown in FIG. 3). A second ultrasonic oscillator 92 is connected to the second central electrode 55 and the second peripheral electrode 56.

The second ultrasonic oscillator 92 includes a high-frequency power source and supplies high-frequency power of a second frequency higher than the first frequency to the second region 36 of the dome portion 30 via the second central electrode 55 and the second peripheral electrode 56. As a result, the second region 36 of the dome portion 30 is ultrasonically vibrated in its entirety at the second frequency by the second ultrasonic oscillator 92.
In this embodiment, the second frequency is a relatively high frequency, for example, a frequency in the range of 1 MHz to 2 MHz.

The ultrasonic vibrations of the first region 35 or the second region 36 of the dome portion 30 are radiated as ultrasonic vibrations 600 from the concave lower surface 261 of the dome portion 30 toward the cleaning water 500 temporarily stored in the second chamber 222 of the case 20.

That is, in this embodiment, the underside 261 of the dome portion 30 is a radiation surface that radiates ultrasonic vibrations 600. Also, the first region 35 in the dome portion 30 is a region that ultrasonically vibrates the cleaning water 500 at a first frequency, and the second region 36 is a region that ultrasonically vibrates the cleaning water 500 at a second frequency that is higher (greater) than the first frequency.

The annular flange 31 of the ultrasonic vibration plate 3 protrudes radially outward from the outer periphery of the dome 30. The flange 31, like the dome 30, is made of a piezoelectric element, etc.

The annular plate 32 of the ultrasonic vibration plate 3 projects radially outward from the outer periphery of the flange portion 31. The end of the outer periphery of this annular plate 32 is supported by the side wall 23 of the case 20, and fixes the dome portion 30 in the hollow inside the case 20. The portion of the annular plate 32 that is not supported by the side wall 23 amplifies the ultrasonic vibrations 600.

In this way, the case 20 supports the annular plate 32 of the ultrasonic vibration plate 3, and the second chamber 222 functions as a water reservoir that stores water on the recessed surface side of the ultrasonic vibration plate 3. In addition, the case 20 forms the second chamber 222 as a chamber by supporting the annular plate 32, which is the outer periphery of the ultrasonic vibration plate 3.

The control unit 70 shown in FIG. 1 controls each component of the ultrasonic cleaning device 1 to perform a cleaning operation on the wafer 100 held on the holding table 10 .
The cleaning operation of the ultrasonic cleaning device 1 for cleaning the wafer 100 will be described below.

First, as shown in FIG. 2, the operator places the holding table 10 on the holding part 11 so that the center of the wafer 100 roughly coincides with the center of the holding part 11 of the holding table 10. The control unit 70 then activates a suction source (not shown) to transmit suction force to the holding part 11. As a result, the holding part 11 of the holding table 10 suction-holds the front surface 101 of the wafer 100.

Then, the control unit 70 controls the rotating means 40 to rotate the holding table 10 holding the wafer 100 in the direction of the arrow R2. The control unit 70 also controls the rotating motor 46 of the sliding means 44 to rotate the rotating arm 45 in the direction of the arrow R1. As a result, the ultrasonic cleaning nozzle 2 is moved from a retracted position outside the holding table 10 to above the wafer 100, and the nozzle 241 of the ultrasonic cleaning nozzle 2 faces the surface 102 to be cleaned of the wafer 100.

Then, the control unit 70 starts to send out the cleaning water 500 from the cleaning water supply source 60. The cleaning water 500 passes through the water supply port 231 and is temporarily stored in the second chamber 222 of the case 20 in the ultrasonic cleaning nozzle 2.

A predetermined amount of cleaning water 500 is stored in the second chamber 222 of the case 20, and when the pressure in the second chamber 222 rises, the cleaning water 500 is sprayed downward from the nozzle 241. Note that as the cleaning water 500 continues to be supplied from the cleaning water supply source 60, the amount of cleaning water 500 in the second chamber 222 is maintained at a predetermined amount.

At this time, the control unit 70 also controls the first ultrasonic oscillator 91 to supply high-frequency power of a first frequency to the first region 35 (see FIG. 3) of the dome portion 30 of the ultrasonic vibration plate 3. As a result, the first ultrasonic oscillator 91 repeatedly turns on and off the application of voltage at the first frequency, causing expansion and contraction motion in the up and down direction in the first region 35. This expansion and contraction motion then becomes mechanical ultrasonic vibration.

As a result, the first region 35 of the dome portion 30 ultrasonically vibrates the cleaning water 500 at the first frequency. That is, ultrasonic vibrations 600 of the first frequency are propagated from the underside 261 of the dome portion 30, which includes the first region 35, to the cleaning water 500 temporarily stored in the second chamber 222 of the case 20. In addition, the ultrasonic vibrations 600 propagated to the cleaning water 500 are concentrated toward the nozzle 241.

The ultrasonic vibrations 600 are focused on the surface 102 to be cleaned of the wafer 100, which is positioned at a predetermined position, for example within a range of several millimeters to several tens of millimeters, below the nozzle 241, and are concentrated at this position. In other words, a focal point of the ultrasonic vibrations 600 is formed on the surface 102 to be cleaned.

By the propagation of such ultrasonic vibrations, ultrasonic cleaning water (ultrasonic cleaning water vibrating at the first frequency) that has propagated ultrasonic vibrations 600 of the first frequency is sprayed from the nozzle 241 of the nozzle portion 24 toward the surface 102 to be cleaned of the wafer 100.

The control unit 70 also switches the frequency of the high-frequency power provided to the dome portion 30 after a predetermined time has elapsed since the first ultrasonic oscillator 91 supplied high-frequency power of the first frequency to the first region 35.

That is, the control unit 70 stops the supply of high-frequency power from the first ultrasonic oscillator 91 and controls the second ultrasonic oscillator 92 to supply high-frequency power of the second frequency to the second region 36 (see FIG. 3) of the dome portion 30. As a result, the second ultrasonic oscillator 92 repeatedly turns on and off the application of voltage at the second frequency, causing expansion and contraction motion in the vertical direction in the second region 36. This expansion and contraction motion becomes mechanical ultrasonic vibration.

As a result, the second region 36 of the dome portion 30 ultrasonically vibrates the cleaning water 500 at the second frequency. That is, ultrasonic vibrations 600 of the second frequency are propagated from the underside 261 of the dome portion 30, including the second region 36, to the cleaning water 500 temporarily stored in the second chamber 222 of the case 20. Furthermore, the ultrasonic vibrations 600 propagated to the cleaning water 500 are concentrated toward the nozzle 241. Then, as described above, a focal point of the ultrasonic vibrations 600 is formed on the surface 102 to be cleaned.

By the propagation of such ultrasonic vibrations, ultrasonic cleaning water (ultrasonic cleaning water vibrating at the second frequency) that has propagated ultrasonic vibrations 600 of the second frequency is sprayed from the nozzle 241 of the nozzle portion 24 toward the surface 102 to be cleaned of the wafer 100.

When ultrasonic cleaning water vibrating at the first or second frequency is being sprayed toward the surface 102 of the wafer 100 to be cleaned, the control unit 70 rotates the wafer 100 using the rotation means 40 and rotates the ultrasonic cleaning nozzle 2 using the slide means 44. That is, the control unit 70 moves the wafer 100 and the ultrasonic cleaning nozzle 2 relatively in a direction parallel to the surface 102 of the wafer 100 to be cleaned. As a result, the entire surface 102 of the wafer 100 to be cleaned is cleaned by being sprayed with ultrasonic cleaning water through which ultrasonic vibrations of two different frequencies are propagated.

That is, the dirt adhering to the surface 102 of the wafer 100 to be cleaned is vibrated by the ultrasonic cleaning water and separated from the surface 102 to be cleaned, and the ultrasonic cleaning water containing the dirt flows radially outward over the surface 102 to be cleaned in accordance with the rotation of the holding table 10, flows down into the casing 14, and is discharged to the outside.

As described above, in this embodiment, the ultrasonic cleaning nozzle 2 propagates ultrasonic vibrations of two different frequencies to the cleaning water, and the surface 102 to be cleaned of the wafer 100 is cleaned by the ultrasonic cleaning water to which the ultrasonic vibrations of the two different frequencies have been propagated. Therefore, dust particles of different sizes adhering to the surface 102 to be cleaned can be appropriately removed.

In addition, in this embodiment, the dome portion 30 of one ultrasonic vibration plate 3 is formed with a first region 35 that ultrasonically vibrates the cleaning water 500 at a first frequency, and a second region 36 that ultrasonically vibrates the cleaning water 500 at a second frequency higher than the first frequency. Therefore, ultrasonic cleaning water to which ultrasonic vibrations of two different frequencies are propagated can be sprayed from the ultrasonic cleaning nozzle 2 while preventing the ultrasonic cleaning nozzle 2 from becoming too large.

In this embodiment, the dome portion 30 that generates the ultrasonic vibration 600 is held on the side wall 23 of the case 20 via the flange portion 31 and the annular plate 32. Therefore, the dome portion 30 is likely to vibrate when high-frequency power is supplied to the ultrasonic vibration plate 3. This allows the ultrasonic vibration of large amplitude, amplified by the annular plate 32, to be effectively propagated to the cleaning water 500.
In addition, the distance between the ejection port 241 and the surface 102 to be cleaned of the wafer 100 held on the holding surface 13 may be changed between when cleaning with the first frequency and when cleaning with the second frequency.
For this reason, a lifting means for lifting and lowering the holding table 10 or a lifting means for lifting and lowering the ultrasonic cleaning nozzle 2 may be provided.

In this embodiment, the control unit 70 cleans the surface 102 of the wafer 100 to be cleaned while switching the frequency of the high-frequency power supplied to the dome unit 30. Alternatively, the control unit 70 may simultaneously supply high-frequency power of two different frequencies to the dome unit 30.

That is, the control unit 70 may supply high-frequency power of a first frequency to the first region 35 by the first ultrasonic oscillator 91, and supply high-frequency power of a second frequency to the second region 36 by the second ultrasonic oscillator 92. As a result, the control unit 70 propagates ultrasonic vibrations of the first frequency and ultrasonic vibrations of the second frequency from the underside 261 of the dome portion 30 to the cleaning water 500 in the second chamber 222.

As a result, ultrasonic cleaning water vibrating at the first frequency and the second frequency is sprayed from the spray nozzle 241 toward the surface 102 to be cleaned of the wafer 100. That is, ultrasonic cleaning water in which the ultrasonic vibrations of the first frequency and the ultrasonic vibrations of the second frequency are superimposed (mixed) and propagated is sprayed onto the surface 102 to be cleaned.
Even with this configuration, dust particles of different sizes adhering to the surface 102 to be cleaned can be appropriately removed by the ultrasonic cleaning water to which ultrasonic vibrations of two different frequencies are propagated.

In addition, in this embodiment, the dome portion 30 includes a second region 36 that is circular when viewed from above and is located in the center, and a first region 35 that concentrically surrounds the second region 36. In this regard, the shapes of the first region 35 and the second region 36 formed in the dome portion 30 are not limited to this.

For example, the ultrasonic vibration plate 3 (dome portion 30) may have at least two sector-shaped regions with the apex of the central angle located at the center of the ultrasonic vibration plate 3 (dome portion 30). The adjacent sector-shaped regions may be a first region 35 and a second region 36. The apex of the central angle of the sector is the intersection of two radii (straight lines) of the sector that form the central angle of the sector.

That is, the first region 35 and the second region 36 may be formed as sector-shaped regions when viewed from above.
4, the first region 35 and the second region 36 are formed as semicircular sector regions having a central angle of 180 degrees so as to bisect the dome portion 30. In this configuration as well, a first central electrode 51 and a second central electrode 55 are formed at the centers of the first region 35 and the second region 36, respectively.

In the same manner as in the configuration shown in FIG. 3, a first ultrasonic oscillator 91 is connected to the first central electrode 51 and the first peripheral electrode 52, and a second ultrasonic oscillator 92 is connected to the second central electrode 55 and the second peripheral electrode 56.

In the example shown in FIG. 5, the first region 35 and the second region 36 are formed as sector-shaped regions with a central angle of 90 degrees, dividing the dome portion 30 into four equal parts. That is, two each of the first region 35 and the second region 36, each of which is a sector with a central angle of 90 degrees, are formed in the dome portion 30. In this configuration, the first region 35 and the second region 36 are formed so as to be alternately arranged along the circumferential direction of the dome portion 30.

Each of the first regions 35 and each of the second regions 36 has a first central electrode 51 and a second central electrode 55 at its center, respectively. A first ultrasonic oscillator 91 is connected to each of the first central electrodes 51 and each of the first peripheral electrodes 52, and a second ultrasonic oscillator 92 is connected to each of the second central electrodes 55 and each of the second peripheral electrodes 56.

When using the dome portion 30 of the configuration shown in Figures 4 and 5, as in the case of using the dome portion 30 shown in Figure 3, the ultrasonic cleaning water to which ultrasonic vibrations of two different frequencies are propagated can properly remove dust particles of different sizes adhering to the surface 102 to be cleaned of the wafer 100.

In addition, in this embodiment, the ultrasonic vibration plate 3 is a concave spherical plate, and includes a dome portion 30 including a concave lower surface 261 as a member including the first region 35 and the second region 36. In this regard, the ultrasonic vibration plate 3, which is a circular plate, does not need to include a dome-shaped member such as the dome portion 30.

For example, as shown in FIG. 6, the ultrasonic vibration plate 3 may have a flat plate member 34 including a first region 35 and a second region 36 that are circular in top view, instead of the dome portion 30. The first region 35 and the second region 36 formed in the flat plate member 34 may be concentric regions as shown in FIG. 3, or may be sector-shaped regions as shown in FIGS. 4 and 5.

In addition, in this embodiment, the dome portion 30 of the ultrasonic vibration plate 3 is composed of a piezoelectric element. In this regard, the dome portion 30 may be equipped with a vibration body other than a piezoelectric element.

In addition, in this embodiment, the ultrasonic cleaning nozzle 2 has a first region 35 and a second region 36 on the ultrasonic vibration plate 3, and is configured to propagate ultrasonic waves of two different frequencies into the cleaning water. In this regard, the ultrasonic cleaning nozzle 2 may be configured to propagate ultrasonic waves of three or more different frequencies into the cleaning water. In this case, the ultrasonic cleaning nozzle 2 may have three or more regions on the ultrasonic vibration plate 3 for oscillating ultrasonic waves of three or more different frequencies.

,
1: ultrasonic cleaning device, 70: control unit,
14: casing, 120: outer wall, 122: bottom plate, 124: legs,
10: holding table, 11: holding portion, 12: frame, 13: holding surface,
4: moving means, 40: rotating means, 41: spindle, 42: rotation drive source,
44: slide means, 45: swivel arm, 46: swivel motor,
2: ultrasonic cleaning nozzle,
20: case, 21: bottom plate, 22: top plate, 23: side wall, 24: nozzle portion,
221: first chamber, 222: second chamber, 231: water supply port, 241: jet port,
3: ultrasonic vibration plate,
30: dome portion, 31: flange portion, 32: annular plate, 34: flat plate member, 261: lower surface,
35: first region, 36: second region,
51: first central electrode; 52: first peripheral electrode;
55: second central electrode; 56: second peripheral electrode;
60: cleaning water supply source, 91: first ultrasonic oscillator, 92: second ultrasonic oscillator,
100: wafer, 101: front surface, 102: surface to be cleaned,
500: cleaning water, 600: ultrasonic vibration

Claims (4)

An ultrasonic cleaning nozzle that sprays cleaning water through which ultrasonic vibrations are propagated onto an object to be cleaned,
A circular ultrasonic vibration plate;
a case including an injection port disposed opposite to the ultrasonic vibration plate and supporting an outer periphery of the ultrasonic vibration plate to form a chamber;
a supply port formed through a side wall of the case for supplying cleaning water into the chamber;
The ultrasonic vibration plate is
a first region for ultrasonically vibrating the cleaning water at a first frequency;
and a second region for ultrasonically vibrating the cleaning water at a second frequency higher than the first frequency,
The first region and the second region are sector-shaped regions whose central angle vertices are located at the center of the ultrasonic vibration plate.
Ultrasonic cleaning nozzle. the first region and the second region are sector-shaped regions having a central angle of 90 degrees,
The first regions and the second regions are formed in pairs so as to be alternately arranged along the circumferential direction of the ultrasonic vibration plate.
The ultrasonic cleaning nozzle according to claim 1. The ultrasonic vibration plate is a concave spherical plate having a concave surface facing the injection port.
The ultrasonic cleaning nozzle according to claim 1. the ultrasonic vibration plate has an annular plate at its outer periphery, the annular plate being supported by the case for amplifying ultrasonic vibrations in the first region and the second region;
The ultrasonic cleaning nozzle according to claim 1.