JP2005131602A - Cleaner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaner capable of stably generating an ultrasonic standing wave when cleaning a glass substrate, a silicon substrate, or the like, used in a manufacturing process for a flat panel display and a semiconductor, and capable of reducing the amount of a cleaning liquid used. <P>SOLUTION: This cleaner is constituted of a transfer roller 2 as a transferring mechanism transferring a substrate 1 to be cleaned, a reflection plate 9 reflecting an ultrasonic wave which is positioned at the surface 1a to be cleaned side of the substrate 1 to be cleaned, a jet nozzle 3 spraying the cleaning liquid 5 between the surface 1a to be cleaned of the substrate 1 to be cleaned and the inner surface 9a of the reflection plate 9, and an ultrasonic nozzle 7 spraying a liquid 8 applied by an ultrasonic wave onto the back surface 1b of the surface 1a to be cleaned of the substrate 1 to be cleaned. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cleaning device used in, for example, a liquid crystal display element, a flat panel display such as a plasma display panel (PDP), and a semiconductor manufacturing process.

  For example, conventional cleaning methods used in the manufacturing process of flat panel displays such as liquid crystal display elements and PDPs (plasma display panels) and semiconductors include brush cleaning by rubbing a rotating brush on the surface of the substrate to be cleaned, and ultrasonic waves in the cleaning liquid. Suggested are cavitation cleaning using the impact force generated when the cavity is collapsed by irradiation, megasonic cleaning using high-frequency vibration acceleration, and high-speed flow cleaning using the shear force of the flow by jetting the cleaning liquid at high speed. Has been.

  Further, in these cleaning methods, a plurality of substrates to be cleaned are immersed in the cleaning liquid at a time for cleaning, or a dip method, or cleaning liquid is sprayed toward the substrate to be cleaned and cleaned one by one. A single wafer method is used. Recently, a single wafer method that can achieve a high cleanliness and is advantageous in terms of cost for cleaning a large substrate is often used.

  As one of the single wafer methods, there is a cleaning method in which, for example, ultrasonic vibration is added to the cleaning liquid sprayed onto the substrate to be cleaned, and the fine particles are removed from the substrate to be cleaned by acceleration and straight flow of the cleaning liquid by ultrasonic vibration. It has been put into practical use. For ultrasonic transducers used in ultrasonic cleaning devices that utilize ultrasonic waves, if the frequency is too low, the effect of applying ultrasonic waves to the cleaning liquid is difficult to develop, and if the frequency is too high, the substrate to be cleaned by cavitation is Since there is concern about damage, a frequency of about 1 MHz is used.

  Patent Document 1 discloses a cleaning device that includes a cleaning tank, an ultrasonic vibrator, and a reflector, and stores a cleaning liquid in the cleaning tank. In this cleaning apparatus, the ultrasonic wave oscillated from the ultrasonic vibrator is reflected by a reflecting plate to generate a standing wave, and the antinode of the standing wave is positioned on the surface of the substrate to be cleaned.

  Patent Document 2 discloses the following cleaning apparatus. The nozzle structure 150 as shown in FIG. 13 has an introduction passage 110 for introducing the cleaning liquid 105 and a discharge passage 112 for discharging the cleaning liquid 105 after the cleaning process out of the system of the cleaning process. A suction pump 113 is provided at the end of the discharge passage. The introduction passage 110 and the discharge passage 112 are connected to each other at an intersection 114, and an opening 106 that opens toward the substrate to be cleaned 101 is provided in the intersection 114. A vibrator 120 is provided at the intersection 114.

  The substrate 101 to be cleaned is transported in the direction of arrow F by the transport roller 102, and the oscillation of the ultrasonic vibrator 120 provided at the intersection 114 of the nozzle structure 150 is oscillated from the opening 106 via the cleaning liquid 105. 101, the particles on the substrate to be cleaned 101 are removed.

By controlling the suction pressure of the suction pump 113, the pressure of the cleaning liquid 105 in contact with the atmosphere of the opening 106 and the atmospheric pressure are balanced. That is supplied to the substrate to be cleaned 101 through the opening 106 by the relationship between the pressure _{P W} and the atmospheric pressure _{P a} of the cleaning liquid 105 in contact with the atmosphere of the opening 106 and the _{P W} ≒ _{P a,} The cleaning liquid 105 in contact with the substrate to be cleaned 101 is discharged from the discharge passage 112 without leaking outside. That is, the cleaning liquid 105 supplied from the introduction passage 110 to the substrate to be cleaned 101 is removed from the substrate to be cleaned 101 without contacting any portion other than the portion supplied with the cleaning liquid.
JP 2000-107710 A Japanese Patent Laid-Open No. 10-163153

  Flat panel displays such as liquid crystal display elements and PDPs (plasma display panels) will require larger substrates and higher definition in the future in order to improve productivity in multi-cavity processing. The following issues remain.

  In order to secure a production capacity equal to or greater than that of a conventional large substrate, the substrate transport speed is increased. Here, since the cleaning performance by ultrasonic vibration is proportional to the ultrasonic irradiation time for the substrate to be cleaned, the cleaning performance deteriorates if the conveying speed is increased and the ultrasonic irradiation time per unit area of the substrate is shortened.

  Since the cleaning apparatus described in Patent Document 1 stores the cleaning liquid in the cleaning tank, it is necessary to increase the size of the cleaning tank in order to cope with a large substrate, which increases the amount of the cleaning liquid used and the processing cost. There is. Moreover, since the frequency of the applied ultrasonic wave is 100 KHz or less, there is a problem that it is not possible to deal with minute particles of 1 μm or less.

  In the cleaning apparatus described in Patent Document 2, since the standing wave is formed by reflecting the ultrasonic wave on the back surface of the substrate to be cleaned, the position of the antinode where the amplitude of the standing wave is maximum is stabilized on the surface of the substrate to be cleaned. It becomes difficult.

Further, since the size of the substrate 101 to be cleaned is increased, the influence of the warp of the substrate 101 to be cleaned becomes large. To cope with the substrate 101 to be cleaned having a large warp, the lower surface of the intersection 114 and the transport roller 102 are used. It is necessary to increase the distance from the upper end surface of the. Keeping the pressure P _W and the atmospheric pressure P _a of the cleaning liquid 105 in contact with the atmosphere in that case the opening 106 substantially equal relationship becomes difficult.

  Accordingly, an object of the present invention is to provide an ultrasonic standing wave when cleaning a glass substrate, a silicon substrate or the like used in a flat panel display such as a liquid crystal display element or PDP (plasma display panel) or a semiconductor manufacturing process. It is an object of the present invention to provide a cleaning device that can stably generate water and can reduce the amount of cleaning liquid used.

  According to the cleaning apparatus of the present invention, the transport mechanism for transporting the substrate to be cleaned with its surface to be cleaned facing upward, the high-pressure nozzle for injecting the cleaning liquid onto the surface to be cleaned of the substrate to be cleaned, and the substrate to be cleaned An ultrasonic nozzle that ejects a liquid to which ultrasonic waves are applied, and a liquid film thickness stabilizing unit that stabilizes the liquid film thickness of the cleaning liquid above the ultrasonic nozzle.

  According to the cleaning device, since the liquid film thickness stabilizing means is provided, the liquid film thickness of the cleaning liquid sprayed from the high pressure nozzle is stabilized. As a result, it is easy to stably generate a standing wave, and vibration energy can be stably applied to particles adhering to the surface to be cleaned of the substrate to be cleaned. In addition, the ultrasonic wave is propagated to the substrate to be cleaned using the liquid sprayed on the lower surface of the substrate to be cleaned as a medium, and further, the ultrasonic wave is propagated and determined by this liquid and the cleaning liquid sprayed on the surface to be cleaned of the substrate to be cleaned. Since a standing wave is generated, a cleaning tank for storing a cleaning liquid as in a conventional cleaning device is not necessary. As a result, even when the substrate to be cleaned is enlarged, an increase in the amount of cleaning liquid used can be minimized.

  Preferably, in the cleaning device, when the wavelength of the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle is λ, the vibrator for applying the ultrasonic wave to the liquid ejected from the ultrasonic nozzle and the object to be cleaned The distance to the surface is a natural number multiple of approximately λ / 2. With this configuration, the position of the antinode of the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle on the surface to be cleaned can be made to substantially coincide with the surface to be cleaned of the substrate to be cleaned, and the particles on the surface to be cleaned of the substrate to be cleaned The vibration energy given to can be maximized, and the cleaning ability is improved.

  More preferably, in the cleaning apparatus, the liquid film thickness stabilizing means is constituted by a liquid film thickness stabilizing member having a plane facing the surface to be cleaned and maintaining a predetermined interval. According to this configuration, the liquid film thickness on the substrate to be cleaned can be stabilized by the plane of the liquid film thickness stabilizing means.

  More preferably, in the cleaning apparatus, the liquid film thickness stabilizing member is disposed between the liquid film thickness stabilizing member and the substrate to be cleaned on the plane facing the surface to be cleaned of the liquid film thickness stabilizing member. There is a cleaning liquid replenishing means for replenishing the cleaning liquid between them. According to this configuration, since the cleaning liquid replenishing means is provided, the cleaning liquid can be replenished even when the liquid film thickness of the cleaning liquid is insufficient, and the liquid film thickness can be further stabilized.

  More preferably, in the cleaning apparatus, the liquid film thickness stabilizing member is configured by a reflector that covers the upper side of the ultrasonic nozzle and reflects the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle, The gap between the surface to be cleaned and the reflecting plate is filled with the cleaning liquid. According to this configuration, since the liquid film thickness stabilizing member is configured by the reflecting plate that reflects the ultrasonic wave, the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle can be reflected by the reflecting plate. As a result, it is easy to stably generate a standing wave, and vibration energy can be stably applied to particles adhering to the surface to be cleaned of the substrate to be cleaned.

  More preferably, in the cleaning apparatus, the surface to be cleaned of the substrate to be cleaned is disposed at a position of an antinode of a standing wave generated between the vibrator and the reflection plate. According to this configuration, the vibration energy given to the particles on the surface to be cleaned can be maximized.

  In the cleaning apparatus, the ultrasonic wave component that is transmitted through the inner surface and reflected from the outer surface of the reflecting plate is more reflective than the ultrasonic component that reflects the reflecting plate at the inner surface of the reflecting plate, such as a glass plate. You may comprise so that it may increase. In this case, when the wavelength of the ultrasonic wave generated by the vibrator is λ, the distance between the outer surface of the reflector and the surface to be cleaned of the substrate to be cleaned is an odd multiple of approximately λ / 4. The anti-node of the standing wave can be positioned on the surface to be cleaned of the substrate to be cleaned.

  In the above cleaning apparatus, the reflecting plate reflects on the inner surface of the reflecting plate rather than the ultrasonic component that passes through the inner surface of the reflecting plate and reflects on the outer surface, such as a rubber plate or a plate having a cavity inside. You may comprise so that the component of the ultrasonic wave to increase may be increased. In this case, when the wavelength of the ultrasonic wave generated by the vibrator is λ, the distance between the inner surface of the reflector and the surface to be cleaned of the substrate to be cleaned is set to an odd multiple of approximately λ / 4. The anti-node of the standing wave can be positioned on the surface to be cleaned of the substrate to be cleaned.

  In the cleaning apparatus, the liquid film thickness stabilizing means may be constituted by a long member having a cylindrical surface whose central axis extends in a direction perpendicular to the transport direction of the substrate to be cleaned and which faces the surface to be cleaned. Good. According to this configuration, the liquid film thickness on the surface to be cleaned can be stabilized by the cylindrical surface.

  More preferably, in the cleaning apparatus, when the wavelength of the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle is λ, the liquid film thickness of the cleaning liquid above the ultrasonic nozzle is an odd number of approximately λ / 4. Is double. According to this configuration, it becomes easy to make the antinode of the standing wave by the ultrasonic wave reflected from the liquid film surface of the cleaning liquid coincide with the surface to be cleaned of the substrate to be cleaned.

  In the cleaning apparatus, more preferably, the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle includes a frequency component of 1 MHz or more. According to this configuration, the ability to remove minute particles is improved.

  According to the cleaning apparatus of the present invention, a standing wave can be generated stably, so that a stable and high cleaning performance can be obtained, and it is not necessary to store the cleaning liquid, so that the amount of the cleaning liquid used can be reduced. it can.

(Embodiment 1)
Hereinafter, the cleaning apparatus according to the present embodiment will be described with reference to the drawings. 1 is a side view showing the structure of the cleaning device in the present embodiment, FIG. 2 is a plan view showing the structure of the cleaning device, and FIGS. 3 and 4 are operations of the cleaning device. It is explanatory drawing explaining these.

  As shown in FIGS. 1 and 2, the cleaning apparatus according to the present embodiment is located on the side of the cleaning surface 1 a of the substrate 1 to be cleaned and the transport roller 2 as a transport mechanism for transporting the substrate 1 to be cleaned. A reflection plate 9 as a liquid film thickness stabilizing means for reflecting ultrasonic waves, a high-pressure nozzle 3 for injecting the cleaning liquid 5 between the surface to be cleaned 1 a of the substrate to be cleaned 1 and the inner surface 9 a of the reflection plate 9, The ultrasonic nozzle 7 which injects the liquid 8 which applied the ultrasonic wave to the back surface 1b of the to-be-cleaned surface 1a of the cleaning substrate 1 is provided.

  The substrate 1 to be cleaned is placed on the transport roller 2 and transported in the direction of the arrow indicated by A in FIGS. The high-pressure nozzle 3 disposed above the surface to be cleaned 1 a of the substrate to be cleaned 1 is disposed at an angle with respect to the surface to be cleaned 1 a of the substrate 1 to be cleaned. The cleaning liquid 5 is jetted at high speed from the slit-shaped jet nozzle 4 of the high-pressure nozzle 3 in the direction opposite to the transport direction of the substrate 1 to be cleaned. The direction is indicated by an arrow B in FIGS. As shown in FIG. 2, the high-pressure nozzle 3 is formed so as to extend over the entire width of the substrate 1 to be cleaned, and the cleaning liquid 5 can be sprayed over the entire width of the substrate 1 to be cleaned.

  An ultrasonic nozzle 7 is arranged on the back surface 1 b side of the substrate 1 to be cleaned, perpendicular to the lower surface of the substrate 1 to be cleaned. From the ultrasonic nozzle 7, the liquid 8 to which ultrasonic waves are applied is ejected upward, that is, in the normal direction of the back surface 1 b of the substrate 1 to be cleaned. As shown in FIG. 2, the ultrasonic nozzle 7 is formed so as to extend over the entire width of the substrate 1 to be cleaned, and can eject the liquid 8 over the entire width of the back surface 1 b of the substrate 1 to be cleaned. By jetting the liquid 8 in this manner, the back surface 1b of the substrate 1 to be cleaned is cleaned, and at the same time, the particles 6 attached to the surface 1a to be cleaned are vibrated by ultrasonic waves applied to the liquid 8, Can surface. The floating particles 6 are removed from the surface of the substrate 1 to be cleaned by the high-speed flow of the cleaning liquid 5 ejected from the high-pressure nozzle 3.

  A reflective plate 9 is arranged in parallel with the substrate to be cleaned 1 above the substrate to be cleaned 1 on the surface to be cleaned 1 a side of the substrate to be cleaned 1. Further, the reflecting plate 9 is for stabilizing the film thickness of the cleaning liquid 5 on the substrate 1 to be cleaned, and for reflecting the ultrasonic wave applied to the liquid 8 ejected from the ultrasonic nozzle 7. The liquid 8 is arranged so as to be orthogonal to the extension line of the liquid 8 ejected from the ultrasonic nozzle 7. The cleaning liquid 5 ejected from the high-pressure nozzle 3 flows between the substrate to be cleaned 1 and the reflection plate 9. At this time, the spraying speed and the spraying amount of the cleaning liquid 5 sprayed from the high-pressure nozzle 3 are adjusted so that the space between the substrate to be cleaned 1 and the reflection plate 9 is filled with the cleaning liquid 5.

  The positional relationship among the reflector 9, the substrate 1 to be cleaned, and the vibrator 10 that generates ultrasonic waves will be described with reference to FIG. The optimum arrangement of these three elements varies depending on the material of the reflecting plate 9, but first, the case where the reflecting plate 9 is a glass plate will be described.

  The ultrasonic wave oscillated from the vibrator 10 reaches the substrate 1 to be cleaned using the liquid 8 ejected from the ultrasonic nozzle 7 as a medium. At this time, since the acoustic impedances of the liquid 8 and the substrate 1 to be cleaned composed of a glass plate are approximately the same order, most of the ultrasonic waves pass through the substrate 1 to be cleaned. This ultrasonic wave propagates to the cleaning liquid 5 ejected from the high-pressure nozzle 3 and reaches the reflection plate 9. Since the acoustic impedances of the reflection plate 9 made of a glass plate and the cleaning liquid 5 that is a liquid are substantially the same, the ultrasonic wave passes through the inner surface 9 a of the reflection plate 9 and propagates into the reflection plate 9. Since the acoustic impedance of the atmosphere in contact with the solid reflector 9 and the outer surface 9b of the reflector 9 is greatly different in order, the ultrasonic waves are reflected by the outer surface 9b of the reflector 9.

  At this time, if the reflecting plate 9 is arranged at a node position where the amplitude of the ultrasonic wave is 0, the ultrasonic wave reflected by the outer surface 9b of the reflecting plate 9 is reflected by the reflecting plate 9, the cleaning liquid 5, and the substrate to be cleaned. 1 and a standing wave 11 that propagates in the order of the liquid 8 and returns to the vibrator 10 is generated. Here, the standing wave 11 has a maximum amplitude (antinode position) on the upper surface of the vibrator 10 and an amplitude of 0 (node position) on the bottom surface of the reflector 9.

  In order to most effectively apply ultrasonic vibration energy to the particles 6, the position of the antinode where the amplitude of the standing wave 11 becomes maximum coincides with the surface to be cleaned 1 a of the substrate to be cleaned 1. It ’s fine. For this purpose, the distance between the outer surface 9b of the reflecting plate 9 and the surface to be cleaned 1a of the substrate 1 to be cleaned may be an odd multiple of λ / 4 where λ is the wavelength of the ultrasonic wave. FIG. 3 shows a case of 1 times λ / 4. Further, the distance between the surface to be cleaned 1a of the substrate to be cleaned 1 and the upper surface of the vibrator 10 may be a natural number multiple of λ / 2. FIG. 3 shows a case of twice λ / 2.

  The reflection component 9 is transmitted through the inner surface 9a and reflected by the outer surface 9b of the reflection plate 9 rather than the ultrasonic component reflected by the inner surface 9a of the reflection plate 9 like the glass plate. In the case of many materials, by setting the positional relationship among the reflector 9, the substrate 1 to be cleaned, and the vibrator 10 as described above, the antinodes of the standing wave and the surface to be cleaned of the substrate 1 to be cleaned are set. The position of 1a can be matched, and the vibration energy of the ultrasonic wave given to the particles adhering to the surface to be cleaned 1a of the substrate to be cleaned 1 can be maximized.

  Next, the case where the reflecting plate 9 is made of a material that easily reflects ultrasonic waves on its surface will be described with reference to FIG. Here, soft rubber is used as such a material. Since the acoustic impedance of the soft rubber is as small as about 1/20 of the acoustic impedance of the cleaning liquid 5, the ultrasonic wave that has propagated through the cleaning liquid 5 is almost reflected by the inner surface 9 a of the reflector 9. In order to make the ultrasonic vibration energy most effectively act on the particles 6 adhering to the surface 1a to be cleaned, the position of the antinode of the standing wave 11 is the same as the surface 1a to be cleaned of the substrate 1 to be cleaned as described above. Just make sure they match. For this purpose, as shown in FIG. 4, the distance between the inner surface 9a of the reflecting plate 9 and the surface 1a to be cleaned of the substrate 1 to be cleaned may be an odd multiple of λ / 4. FIG. 4 shows a case of 1 times λ / 4.

  The distance between the surface to be cleaned 1a of the substrate to be cleaned 1 and the upper surface of the vibrator 10 may be a natural number multiple of λ / 2. FIG. 4 shows a case of twice λ / 2. When the reflector 9 has a cavity and is filled with a gas such as air, the acoustic impedance of the reflector 9 is even smaller than 1/20 of the acoustic impedance of the cleaning liquid 5. The energy of the ultrasonic wave reflected by the inner surface 9a further increases.

  Thus, the reflecting plate 9 is more reflective than the ultrasonic component that is transmitted through the inner surface 9a of the reflecting plate 9 and reflected by the outer surface 9b, such as a soft rubber or a plate having a cavity inside. In the case of a material in which the component of the ultrasonic wave reflected by the inner surface 9a of 9 is larger, the positional relationship among the reflector 9, the substrate 1 to be cleaned, and the vibrator 10 is set as described above. The antinodes of the standing wave and the position of the surface to be cleaned 1a of the substrate to be cleaned 1 can be made to coincide with each other, and the vibration energy of the ultrasonic wave applied to the particles adhering to the surface to be cleaned 1a of the substrate to be cleaned 1 is maximized. be able to.

  The inclination angle of the high pressure nozzle 3 with respect to the substrate to be cleaned 1 is closer to the horizontal with respect to the substrate to be cleaned 1 in order to reduce energy loss when the jet of the cleaning liquid 5 from the high pressure nozzle 3 collides with the substrate to be cleaned 1. Specifically, a range of 10 ° or more and 20 ° or less with respect to the substrate 1 to be cleaned is desirable. In general, the flow velocity component in the direction along the surface to be cleaned 1a of the substrate to be cleaned 1 becomes a cosine component of the ejection flow velocity, so that when the installation angle is 20 °, the attenuation of the flow velocity is 10% or less. On the other hand, when the installation angle is 20 ° or more, the attenuation of the flow velocity increases to 10% or more, and the cleaning power decreases. On the other hand, when the installation angle is less than 10 degrees, the cleaning liquid 5 from the substrate to be cleaned 1 and the high-pressure nozzle 3 is insufficiently brought into contact with the surface to be cleaned 1a of the substrate to be cleaned 1 and the cleaning power is reduced. In this respect, the inclination angle is preferably in the range of 10 ° to 20 °.

  The component of the cleaning liquid 5 from the high-pressure nozzle 3 and the component of the liquid 8 from the ultrasonic nozzle 7 may be the same or different depending on the purpose of cleaning. For example, when cleaning the substrate 1 to be cleaned immediately after purchase, since both surfaces of the substrate 1 to be cleaned are contaminated to substantially the same level, the cleaning liquid 5 from the high-pressure nozzle 3 and the liquid 8 from the ultrasonic nozzle 7 Use the same ingredients. Further, in the substrate 1 to be cleaned after a process such as a film forming process, the surface 1a to be cleaned is severely contaminated. Therefore, the cleaning liquid 5 from the high pressure nozzle 3 uses a chemical solution having a strong cleaning power, and the back surface is not much. Since the liquid 8 from the ultrasonic nozzle 7 is not contaminated, it can be considered to use ultrapure water. As a chemical solution having a strong detergency as described above, any of alkaline hydrogen water, ozone water, hydrogen peroxide water, sulfuric acid, hydrochloric acid, nitric acid, subcritical water, supercritical water, magnetized water, or a mixture thereof A liquid can be used.

  Since the particles to be removed in the present invention are targeted to fine particles of 1 μm or less, the ultrasonic waves applied to the liquid 8 are preferably megasonic ultrasonic waves having a frequency of 1 MHz or more. Since the megasonic ultrasonic wave has a large energy, it can vibrate fine particles of 1 μm or less, and such fine particles can be lifted from the surface to be cleaned 1 a of the substrate to be cleaned 1 during cleaning.

  In the present embodiment, the reflecting plate 9 as the liquid film thickness stabilizing means is disposed on the surface to be cleaned 1a side of the substrate to be cleaned 1, but the action of the cleaning apparatus of this embodiment is such a reflection. This will be described below in comparison with a comparative example using a cleaning apparatus without the plate 9.

  FIG. 5 shows the structure of the cleaning device of the comparative example. As shown in FIG. 5, the only difference from the cleaning apparatus of the present embodiment is the presence or absence of the reflector 9. In the cleaning apparatus of the comparative example, the cleaning liquid 5 is ejected from the slit-shaped jet nozzle 4 of the high-pressure nozzle 3 at a high speed in the conveyance direction (indicated by the arrow A) of the substrate 1 to be cleaned (indicated by the arrow B). The Further, the liquid 8 to which ultrasonic waves are applied from the ultrasonic nozzle 7 is jetted upward onto the surface to be cleaned 1a of the substrate to be cleaned 1 to clean the back surface 1b of the substrate to be cleaned 1 and at the same time, The particles 6 on the cleaning surface 1a are vibrated and floated, and are removed from the surface 1a to be cleaned of the substrate 1 to be cleaned.

  At this time, the cleaning liquid 5 flows in the direction opposite to the transport direction A along the surface to be cleaned 1a of the substrate 1 to be cleaned, but since there is no liquid film stabilizing means, the interface 12 of the cleaning liquid 5 is wavy, Further, the distance between the interface 12 and the substrate to be cleaned 1 varies with time. Since the acoustic impedances of the cleaning liquid 5 and the atmosphere are greatly different in order, most of the ultrasonic waves oscillated from the vibrator 10 are reflected by the interface 12.

  The standing wave is generated and the antinode is positioned on the surface of the substrate 1 to be cleaned only when the distance between the interface 12a and the substrate 1 to be cleaned is λ / 4, which is indicated by a solid line in FIG. When the distance between the interface 12b and the substrate to be cleaned 1 does not coincide with λ / 4, as shown by the broken line in FIG. For this reason, in the case of the comparative example, since the standing wave is not stable, it is difficult to obtain a stable cleaning performance. Further, since a part of the ultrasonic wave passes through the interface 12 and is released into the atmosphere, the vibration energy of the ultrasonic wave is lost and does not contribute to cleaning.

  On the other hand, in the cleaning apparatus of the present embodiment, since the reflection plate 9 is provided, the ultrasonic waves are always reflected at the same position, and a standing wave can be generated stably. As a result, a high cleaning ability can be secured stably. Further, since the ultrasonic wave is reflected by the reflecting plate 9, the loss can be minimized, the energy for vibrating the particles 6 is increased, and the cleaning power is improved.

  Further, in the cleaning apparatus described in Patent Document 1, since the cleaning liquid is stored in the cleaning tank, the cleaning tank is enlarged with an increase in the size of the substrate, and a large amount of cleaning liquid is required, resulting in a large environmental load. There is. On the other hand, in the cleaning apparatus and the cleaning method of the present embodiment, the cleaning liquid 5 and the liquid 8 are sprayed only from the high pressure nozzle 3 and the ultrasonic nozzle 7 to the necessary portions, respectively, and the cleaning tank for storing a large amount of cleaning liquid is Since it is not necessary, water-saving and environmentally friendly cleaning can be realized.

Further, since the cleaning liquid 5 having a high flow rate can be sprayed from the high-pressure nozzle 3 to the surface to be cleaned 1a of the substrate 1 to be cleaned, the cleaning liquid circulating in the cleaning tank as in the cleaning apparatus described in Patent Document 1 is used. The cleaning power is improved as compared with the case of cleaning.
(Embodiment 2)
The cleaning apparatus in Embodiment 2 is demonstrated based on drawing. FIG. 7 is a longitudinal sectional view showing the structure of the cleaning apparatus in the embodiment of the present invention. FIG. 8 is a plan view showing the structure of the cleaning apparatus. FIG. 9 is an explanatory diagram for explaining the operation of the cleaning apparatus.

  The cleaning apparatus according to the present embodiment removes adhered fine particles from a surface to be cleaned 1a that is a surface to be cleaned of the substrate 1 to be cleaned, which is conveyed in the conveyance direction indicated by arrow A, using jet flow and ultrasonic vibration. The device to be removed. This cleaning apparatus is provided at a distance from the surface to be cleaned 1 a of the substrate to be cleaned 1, and provided at a distance from the high pressure nozzle 3 for injecting the cleaning liquid 5 onto the surface to be cleaned 1 a and the back surface 1 b of the substrate to be cleaned 1. The ultrasonic nozzle 7 that ejects the liquid 8 to the back surface 1b and the vibrator 10 that adds vibrations by ultrasonic waves to the liquid 8 ejected from the ultrasonic nozzle 7 are provided.

  The substrate 1 to be cleaned is transported in the direction of arrow A in the figure by the transport means. The conveyance means includes a plurality of conveyance rollers 2, an electric motor 13, and a belt 14 that couples the plurality of conveyance rollers 2 to each other. The rotational driving force by the electric motor 13 is transmitted to each conveyance roller 2 via the belt 14, each conveyance roller 2 rotates around the axis, and the substrate 1 to be cleaned is conveyed in the direction of arrow A. The substrate 1 to be cleaned is cleaned when it passes through a region where the liquid 8 and the cleaning liquid 5 are ejected from the ultrasonic nozzle 7 and the high-pressure nozzle 3 in the course of being conveyed.

  The high-pressure nozzle 3 having the slit-shaped gap 17 is arranged at a certain angle with respect to the substrate 1 to be cleaned, and the cleaning liquid 5 pressurized by the pump is supplied in the direction of arrow C. The curtain-like cleaning liquid 5 is ejected from the gap 17 at a high speed in the direction opposite to the transport direction of the substrate 1 to be cleaned. The width of the water film of the sprayed curtain-like cleaning liquid 5, that is, the length in the direction perpendicular to the transport direction of the water film is longer than the length in the direction perpendicular to the transport direction of the substrate 1 to be cleaned. The inclination angle of the high-pressure nozzle 3 with respect to the substrate 1 to be cleaned is preferably in the range of 10 to 70 °. This inclination angle is a parameter that determines the impact force when the jet of the cleaning liquid 5 from the high-pressure nozzle 3 collides with the substrate to be cleaned 1 and the shear flow velocity after the collision.

  The ultrasonic nozzle 7 extends in a direction perpendicular to the conveyance direction of the substrate 1 to be cleaned, and the length of the nozzle opening in the direction perpendicular to the conveyance direction is longer than the length in the direction perpendicular to the conveyance direction of the substrate 1 to be cleaned. The vibrator 10 is included in the ultrasonic nozzle 7. If the frequency of the ultrasonic wave is too low, the effect of vibration does not appear, and if the frequency is too high, the substrate 1 to be cleaned may be damaged by cavitation. Therefore, 1 MHz ultrasonic wave is preferably used.

  The ultrasonic nozzle 7 cleans the back surface 1b of the substrate 1 to be cleaned by applying the ultrasonic wave generated by the vibrator 10 to the liquid 8 and ejecting the liquid 8 upward. At the same time, the ultrasonic wave applied to the liquid 8 also vibrates and floats the particles on the surface to be cleaned 1 a of the substrate to be cleaned 1, and the particles from the surface to be cleaned 1 a of the substrate to be cleaned 1 by the flow of the cleaning liquid 5 from the high-pressure nozzle 3. Remove.

  Then, a cover 20 is disposed above the ultrasonic nozzle 7 in parallel with the substrate 1 to be cleaned. On the surface of the cover 20 facing the substrate 1 to be cleaned, a plurality of injection holes 21 for ejecting the cleaning liquid are provided as cleaning liquid replenishing means. When the cleaning liquid 5 is supplied in the direction of arrow E, the cleaning liquid 5 is ejected from the injection hole 21 toward the substrate 1 to be cleaned.

  The high-pressure nozzle 3 blows out the cleaning liquid 5 from the gap 17 in a curtain shape to form a water film. The narrower the gap 17, the thinner the water film. The substrate 1 to be cleaned may be warped in the process before cleaning. When such a substrate 1 to be cleaned is cleaned, the distance D1 (see FIG. 9) between the lower surface of the cover 20 and the position where the back surface 1b of the substrate 1 to be cleaned contacts the warp of the substrate 1 to be cleaned. It is necessary to take it widely considering the amount. Further, the cleaning liquid 5 from the high pressure nozzle 3 is preferably thin.

  That is, in the case of cleaning a large substrate, the width of the high-pressure nozzle 3 is wider than that of the substrate 1 to be cleaned, and it is necessary to make the water film 5a thinner in order to reduce the flow rate of the cleaning liquid 5. This also contributes to reducing the burden on the pump for ejection from the high pressure nozzle 3.

  When the thickness of the water film 5a from the high-pressure nozzle 3 is thin and the distance between the lower surface of the cover 20 and the position where the back surface 1b of the substrate 1 to be cleaned contacts the roller 2 is large, the lower surface of the cover 20 and the substrate 1 to be cleaned In order to fill the space between the surface to be cleaned 1 a with the cleaning liquid 5, the cleaning liquid 5 is supplied from the ejection holes 21 to the substrate to be cleaned 1 side. Thus, the space between the lower surface of the cover 20 and the surface to be cleaned 1 a of the substrate to be cleaned 1 is filled with the cleaning liquid, and the ultrasonic wave oscillated by the vibrator 10 can propagate between the liquid 8, the substrate to be cleaned 1, the cleaning liquid 5 and the cover 20. It becomes.

  The positional relationship among the cover 20, the substrate 1 to be cleaned, and the vibrator 10 will be described with reference to FIG. The ultrasonic wave oscillated from the vibrator 10 reaches the substrate 1 to be cleaned using the liquid 8 ejected from the ultrasonic nozzle 7 as a medium. Since the acoustic impedances of the liquid and the solid are approximately the same order, most of the ultrasonic waves pass through the substrate 1 to be cleaned, propagate to the cleaning liquid 5 ejected from the high-pressure nozzle 3 (not shown), and reach the cover 20. Since the acoustic impedances of the cover 20 (solid) and the cleaning liquid 5 (liquid) are almost the same, the ultrasonic wave passes through the inner surface of the cover 20. However, since the acoustic impedances of the cover 20 (solid) and the atmosphere (gas) are greatly different, the ultrasonic waves are reflected on the outer surface of the cover 20.

  Here, when the outer surface of the cover 20 is arranged at a position where the amplitude of the ultrasonic wave becomes 0, the ultrasonic waves reflected by the outer surface of the cover 20 propagate in order to the cleaning liquid 5, the substrate 1 to be cleaned, and the liquid 8. Thus, a standing wave 11 returning to the vibrator 10 is generated. The standing wave 11 has a maximum amplitude (antinode position) on the upper surface of the vibrator 10 and an amplitude of 0 (node position) on the bottom surface of the cover 20.

  In order to make the vibration energy of the ultrasonic wave most effectively act on the particles on the surface to be cleaned 1a, the position of the antinode of the standing wave 11 may be set to be positioned on the surface to be cleaned 1a of the substrate 1 to be cleaned. For this purpose, the distance D2 between the outer surface of the cover 20 and the surface to be cleaned 1a of the substrate to be cleaned 1 should be an odd multiple of λ / 4 (λ is the wavelength of the standing wave). In FIG. 9, D2 is set to 3 times λ / 4. The distance D3 between the surface to be cleaned 1a of the substrate to be cleaned 1 and the upper surface of the vibrator 10 may be a natural number multiple of λ / 2. In FIG. 9, D3 is three times λ / 4.

  As described above, it is possible to perform ultrasonic cleaning that forms a standing wave that is stable, has little loss, and is efficient, and at the same time, a water-saving and environmentally friendly cleaning device can be realized.

In this embodiment, the explanation is made on the premise that pure water is used as the cleaning liquid 5 and the liquid 8, but chemical liquids such as alkaline hydrogen water, ozone water, hydrogen peroxide water, etc. having a strong cleaning power and their mixed liquids are used. May be used.
(Embodiment 3)
A cleaning apparatus according to Embodiment 3 will be described with reference to the drawings. FIG. 10 is a longitudinal sectional view showing the structure of the cleaning apparatus of the present embodiment. FIG. 11 is an explanatory diagram for explaining the operation of the cleaning apparatus. The only difference from the second embodiment is the cover portion, and components having functions equivalent to those in FIGS. 7 to 9 are denoted by the same reference numerals and description thereof will not be repeated.

  In the present embodiment, the gap 17 of the high-pressure nozzle 3 is made wider than that in the second embodiment, and the thickness of the water film of the cleaning liquid 5 blown out from the gap 17 in a curtain shape is set to be thick. Further, the cover 25 is provided such that the distance D between the lower surface of the cover 25 and the surface to be cleaned 1a of the substrate to be cleaned 1 is an odd multiple of λ / 4 (λ is the wavelength of the standing wave). In FIG. 11, D4 is set to be 1 times λ / 4.

  With this configuration, the flow rate of the relatively thick water film 5a formed by the cleaning liquid 5 ejected from the high-pressure nozzle 3 is limited by the cover 25, and the liquid film thickness of the cleaning liquid 5 above the ultrasonic nozzle 7 is reduced. Stabilize.

  The positional relationship among the cover 25, the substrate to be cleaned 1 and the vibrator 10 will be described with reference to FIG. The ultrasonic wave oscillated from the vibrator 10 reaches the substrate 1 to be cleaned from the ultrasonic nozzle 7 by using the liquid 8 as a medium. However, since the acoustic impedance of the liquid and the solid is almost the same order, most of the ultrasonic wave is to be cleaned. It passes through the substrate 1 and propagates to the cleaning liquid 5 sprayed from the high-pressure nozzle 3 (not shown), and reaches the interface between the cleaning liquid 5 and the atmosphere.

  Since the acoustic impedances of the cleaning liquid 5 (liquid) and the atmosphere (gas) are greatly different in order, the ultrasonic waves are reflected at the interface 5b between the cleaning liquid 5 (liquid) and the atmosphere. Here, when the interface 5b is disposed at a position where the amplitude of the ultrasonic wave becomes 0, the ultrasonic wave reflected by the interface 5b propagates to the cleaning liquid 5, the substrate 1 to be cleaned, and the liquid 8 to the vibrator 10. A returning standing wave 11 is generated. The standing wave 11 has the maximum amplitude (antinode position) on the upper surface of the vibrator 10, and the amplitude becomes 0 (node position) at the interface 5b.

  Here, it is the installation height of the cover 25 that determines the position of the interface 5b. The flat surface constituting the lower surface of the cover 25 is installed so as to have an optimum height with respect to the interface 5b.

  In order to make ultrasonic vibration energy most effectively act on the particles on the surface to be cleaned 1a, the position of the antinode of the standing wave 11 is set to coincide with the surface to be cleaned 1a of the substrate 1 to be cleaned. For this purpose, the distance D4 between the lower surface of the cover 25 and the surface to be cleaned 1a of the substrate to be cleaned 1 should be an odd multiple of λ / 4 (λ is the wavelength of the standing wave). In FIG. 11, it is set to 1 times λ / 4. The distance D3 between the surface to be cleaned 1a of the substrate to be cleaned 1 and the upper surface of the vibrator 10 may be a natural number multiple of λ / 2 (λ is the wavelength of the standing wave). In FIG. 11, it is set to twice λ / 2.

  Next, a modification of the third embodiment will be described with reference to the drawings. In addition, FIG. 12 is explanatory drawing explaining operation | movement of the washing | cleaning apparatus in the modification of Embodiment 3. FIG.

  The cover 25 having a rectangular cross section is replaced with a cylinder 30 having a circular cross section. The role of the cylinder 30 is the same as that of the cover 25 described above. With this cylinder 30, the liquid film thickness of the cleaning liquid 5 ejected from the high-pressure nozzle 3 can be made constant. Here, the liquid film thickness stabilizing means is constituted by the cylinder 30. In this case, the liquid film thickness of the cleaning liquid on the surface to be cleaned 1a is the maximum of the cylindrical surface of the cylinder 30 facing the surface to be cleaned 1a. This corresponds to the distance D4 between the lower position and the surface to be cleaned 1a. Therefore, in this modification, D4 is set to be an odd multiple of λ / 4. In FIG. 12, it is set to 1 times λ / 4.

  According to the cleaning apparatus of the present embodiment, the substrate to be cleaned 1 is moved by the transport roller 2, and the cleaning liquid 5 ejected by the high-pressure nozzle 3 installed above the substrate to be cleaned 1 and below the substrate to be cleaned 1. Substrate cleaning is performed by applying ultrasonic waves from the installed ultrasonic nozzle 7, and the cleaning liquid 5 from the high-pressure nozzle 3 flows on the surface to be cleaned 1 a and reaches the position above the ultrasonic nozzle 7. A cover 25 or a cylinder 30 is provided as a liquid film thickness stabilizing means for stabilizing the film thickness. Since the liquid film thickness on the substrate 1 to be cleaned can be made uniform by the liquid film thickness stabilizing means, the vibrator 10 can be easily set.

  Further, since the setting conditions of the vibrator 10 do not change during cleaning, it is possible to apply ultrasonic waves to the liquid 8 under the adjusted optimum conditions, and a stable standing wave whose surface to be cleaned 1a coincides with its antinodes. Can be generated.

  As described above, it is possible to perform ultrasonic cleaning that forms a standing wave that is stable, has little loss, and is efficient, and at the same time, a water-saving and environmentally friendly cleaning device can be realized.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become the basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the claims. Further, all modifications within the meaning and scope equivalent to the scope of the claims are included.

It is a side view which shows the structure of the washing | cleaning apparatus in Embodiment 1 based on this invention. It is a top view which shows the structure of the washing | cleaning apparatus in Embodiment 1 based on this invention. It is explanatory drawing explaining operation | movement of the washing | cleaning apparatus in Embodiment 1 based on this invention. It is explanatory drawing explaining operation | movement of the washing | cleaning apparatus in Embodiment 1 based on this invention. It is a side view which shows the structure of the washing | cleaning apparatus of a comparative example. It is explanatory drawing explaining operation | movement of the washing | cleaning apparatus of a comparative example. It is a longitudinal cross-sectional view which shows the structure of the washing | cleaning apparatus in Embodiment 2 based on this invention. It is a top view which shows the structure of the washing | cleaning apparatus in Embodiment 2 based on this invention. It is explanatory drawing explaining operation | movement of the washing | cleaning apparatus in Embodiment 2 based on this invention. It is a longitudinal cross-sectional view which shows the structure of the washing | cleaning apparatus in Embodiment 3 based on this invention. It is explanatory drawing explaining operation | movement of the washing | cleaning apparatus in Embodiment 3 based on this invention. It is explanatory drawing explaining operation | movement of the washing | cleaning apparatus in the modification of Embodiment 3 based on this invention. It is a longitudinal cross-sectional view which shows the structure of the conventional washing | cleaning apparatus.

Explanation of symbols

  1 Substrate to be cleaned, 1a Surface to be cleaned, 2 Transport roller, 3 High pressure nozzle, 5 Cleaning liquid, 7 Ultrasonic nozzle, 8 Liquid, 9 Reflector, 10 Vibrator, 11 Standing wave, 20 Cover (Liquid film stabilization Means), 21 injection holes (cleaning liquid replenishing means), 25 cover (liquid film thickness stabilizing means), 30 cylinder (liquid film thickness stabilizing means).

Claims (14)

A transport mechanism for transporting the substrate to be cleaned with the surface to be cleaned facing upward;
A high-pressure nozzle for injecting a cleaning liquid onto the surface to be cleaned of the substrate to be cleaned;
An ultrasonic nozzle that ejects a liquid to which ultrasonic waves are applied to the lower surface of the substrate to be cleaned;
A cleaning apparatus comprising: a liquid film thickness stabilizing unit that stabilizes the liquid film thickness of the cleaning liquid above the ultrasonic nozzle.   If the wavelength of the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle is λ, the distance between the vibrator for applying the ultrasonic wave to the liquid ejected from the ultrasonic nozzle and the surface to be cleaned is approximately λ. The cleaning apparatus according to claim 1, which is a natural number multiple of / 2.   The cleaning apparatus according to claim 1, wherein the liquid film thickness stabilizing unit includes a liquid film thickness stabilizing member having a flat surface facing the surface to be cleaned and maintaining a predetermined interval.   The liquid film thickness stabilizing member is for replenishing a cleaning liquid between the liquid film thickness stabilizing member and the substrate to be cleaned on the plane opposite to the surface to be cleaned of the liquid film thickness stabilizing member. The cleaning apparatus according to claim 3, further comprising a cleaning liquid replenishing unit.   The liquid film thickness stabilizing member is a reflecting plate that covers an upper portion of the ultrasonic nozzle and reflects ultrasonic waves applied to the liquid ejected from the ultrasonic nozzle, and includes the reflection plate and the surface to be cleaned. The cleaning apparatus according to claim 3 or 4, wherein a gap is filled with the cleaning liquid.   The cleaning apparatus according to claim 5, wherein a surface to be cleaned of the substrate to be cleaned is disposed at an antinode of a standing wave generated between the vibrator and the reflector. The reflecting plate is configured so that more ultrasonic components are transmitted through the inner surface and reflected from the outer surface of the reflecting plate than are ultrasonic components reflected from the inner surface of the reflecting plate;
When the wavelength of the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle is λ, the distance between the outer surface of the reflecting plate and the surface to be cleaned of the substrate to be cleaned is an odd multiple of approximately λ / 4. The cleaning apparatus according to claim 5 or 6.   The cleaning apparatus according to claim 7, wherein the reflection plate is a glass plate. The reflecting plate is configured such that the ultrasonic component reflected on the inner surface of the reflecting plate is greater than the ultrasonic component transmitted on the inner surface of the reflecting plate and reflected on the outer surface thereof,
When the wavelength of the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle is λ, the distance between the inner surface of the reflecting plate and the surface to be cleaned of the substrate to be cleaned is an odd multiple of approximately λ / 4. The cleaning apparatus according to claim 5 or 6.   The cleaning apparatus according to claim 9, wherein the reflecting plate is a rubber plate.   The cleaning apparatus according to claim 9 or 10, wherein the reflector has a cavity inside. 2. The liquid film stabilization means according to claim 1, comprising a long member having a cylindrical surface whose central axis extends in a direction orthogonal to a transport direction of the substrate to be cleaned and faces the surface to be cleaned. The cleaning device described.   The liquid film thickness of the cleaning liquid above the ultrasonic nozzle is an odd multiple of approximately λ / 4, where λ is the wavelength of the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle. The cleaning apparatus according to 3 or 12.   The cleaning apparatus according to any one of claims 1 to 13, wherein the ultrasonic wave applied to the liquid ejected from the ultrasonic nozzle includes a frequency component of 1 MHz or more.

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