JP2007253121A - Ultrasonic cleaning equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic cleaning device capable of enhancing a cleaning effect. <P>SOLUTION: In this ultrasonic cleaning device, an opening is formed at a tip end, the opening is covered with a membrane having ultrasonic wave permeability, an ultrasonic vibrator is disposed at an upper part inside the device, and a cleaning head is composed by filling an ultrasonic propagation liquid inside. A cover is disposed to cover the tip end of the cleaning head, a slit is formed on the bottom wall of the cover, cleaning liquid is fed to a space demarcated by the cover and the tip end of the cleaning head, and the cleaning liquid is fed to the surface of a substrate through the slit while emitting the ultrasonic wave from the ultrasonic vibrator to the substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a cleaning device for cleaning an object to be cleaned such as a glass substrate of a liquid crystal display device, a glass substrate for a photomask, a substrate for an optical disk, a semiconductor wafer, and the like, particularly when the cleaning liquid is irradiated with ultrasonic waves by a vibrator. The present invention relates to an ultrasonic cleaning device using impact force.

  In the manufacturing process of liquid crystal display devices and semiconductors, an ultrasonic cleaning device is used to quickly and reliably remove contaminants such as particles adhering to the surface of a glass substrate or wafer (hereinafter referred to as a substrate). (For example, refer to Patent Document 1).

The ultrasonic cleaning device disclosed in Patent Document 1 injects acoustic transmission water into the casing from the acoustic transmission water injection hole, fills the casing with acoustic transmission water, and from the cleaning liquid injection hole to the inside of the horn member, The ultrasonic transducer is driven while injecting the cleaning liquid into the reflecting member from the cleaning liquid injection hole. The mechanical vibration is transmitted to the side wall of the casing by the ultrasonic vibrator, which acts as a diaphragm and is transmitted to the acoustic transmission water filled in the casing. The sound of the acoustic transmission water is transmitted to the cleaning liquid that passes through the radiation plate and flows in the horn member and on the reflecting member, and acceleration force, cavitation, and straight flow are generated in the cleaning liquid by the transmitted sound. Then, the object to be cleaned is cleaned by being positioned in a slit formed between the radiation plate and the reflecting member. Therefore, by using the ultrasonic cleaning apparatus, it is possible to obtain the cleaning effect by the cleaning liquid and the cleaning effect by the ultrasonic wave.
JP 2004-154771 A (see FIGS. 3, 4 and 7)

By the way, as the cleaning liquid supplied to the ultrasonic cleaning apparatus, pure, ammonia water (NH ₄ OH), hydrogen peroxide water (H ₂ O ₂ ), or the like is used. These washing waters are used at a high temperature of about 80 ° C.

  As described above, in the ultrasonic cleaning apparatus, a chemical liquid that is relatively easy to vaporize is used as the cleaning liquid and is used at a high temperature, so that bubbles are generated inside the cleaning liquid. Then, the generated bubbles float because the specific gravity is light with respect to the cleaning liquid, and remain in the vicinity of the radiation plate. Thus, when bubbles accumulate, the ultrasonic energy radiated from the acoustic transmission water is blocked by the bubbles and is not transmitted to the cleaning liquid, and the ultrasonic wave radiated from the acoustic transmission water is weakened to obtain a sufficient cleaning effect. I can't. Further, since it is necessary to fill the horn member with the cleaning water, the residence time of the cleaning water becomes long, and there is a possibility that the concentration of the microbubbles dissolved in the cleaning liquid is lowered.

  Then, an object of this invention is to provide the ultrasonic cleaning apparatus which can improve a cleaning effect in view of the said problem.

  The ultrasonic cleaning apparatus according to claim 1 is formed with an opening at the tip, covered with an ultrasonically permeable diaphragm, an ultrasonic transducer is disposed in the upper part of the ultrasonic cleaning device, and an ultrasonic propagation liquid is provided in the inner part. The cleaning head is filled to form a cover, and a cover is disposed so as to cover the tip of the cleaning head, a slit is formed in the bottom wall of the cover, and is defined by the cover and the tip of the cleaning head. The cleaning liquid is supplied to the space portion to be cleaned, and the cleaning liquid is supplied from the slit to the surface of the object to be cleaned while irradiating the ultrasonic wave from the ultrasonic vibrator.

  The ultrasonic cleaning apparatus according to claim 2 is characterized in that, in the invention according to claim 1, the tip of the cleaning head is formed in a tapered shape so that a cross section in the advancing direction of the cleaning object becomes narrower toward the tip. .

  The ultrasonic cleaning apparatus according to claim 3 is characterized in that, in the invention of claim 1 or 2, an ultrasonic transmission having an ultrasonic transmittance of 80% or more is used as the diaphragm.

  The ultrasonic cleaning apparatus according to a fourth aspect is the ultrasonic cleaning apparatus according to any one of the first to third aspects, wherein the cleaning head is disposed to face both surfaces of the object to be cleaned so as to simultaneously clean both surfaces of the object to be cleaned. It is characterized by that.

  According to the first aspect of the present invention, the cover is disposed at the tip of the cleaning head to form a small space, the cleaning liquid is supplied to the small space, and the cleaning liquid is directed to the object to be cleaned from the slit formed in the cover. Since the liquid is supplied, there is no possibility that bubbles of the cleaning liquid stay in the ultrasonic wave propagation path. Thereby, since an ultrasonic wave can be irradiated efficiently, cleaning efficiency improves.

  According to the invention of claim 2, since the small space defined by the cleaning head and the cover can be further reduced, the cleaning liquid can be reduced.

  According to the invention of claim 3, since the ultrasonic energy can be transmitted to the cleaning liquid without deteriorating the ultrasonic transmission performance, the cleaning effect can be further enhanced.

  According to invention of Claim 4, both surfaces of a to-be-cleaned object can be wash | cleaned simultaneously, and the working efficiency in double-sided washing can be improved.

  Hereinafter, an ultrasonic cleaning apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  1 is a cross-sectional perspective view conceptually showing an ultrasonic cleaning apparatus according to an embodiment, FIG. 2 is a schematic view showing the ultrasonic cleaning apparatus shown in FIG. 1, and FIGS. 3 and 4 are different in material. FIG. 5 is a graph showing ultrasonic transmission characteristics and the number of residual particles on the substrate (object to be cleaned).

  The ultrasonic cleaning apparatus 1 shown in FIG. 1 includes an ultrasonic generation unit 10, a cleaning liquid supply unit 20, a substrate transfer unit 30, and the like.

The ultrasonic generator 10 includes a cleaning head 11. The cleaning head 11 has a box shape having a width wider than the width of the substrate A, and a front end portion (lower portion in the embodiment) is tapered in a cross section in the traveling direction of the substrate A. At the tip of the cleaning head 11, an opening 11a extending in a direction parallel to the traveling direction surface of the substrate A and perpendicular to the traveling direction of the substrate A is formed. 12 is disposed. The material of the diaphragm 12 is not particularly limited as long as the material can withstand ultrasonic energy and has chemical resistance (for example, polyester, polyethylene, quartz, etc.). The ultrasonic permeability of the diaphragm 12 is calculated from the following formula 1 depending on the diaphragm density, diaphragm thickness, propagation liquid density, and ultrasonic frequency used. Therefore, the optimum thickness of the diaphragm 12 can be determined in accordance with the ultrasonic frequency to be used and the diaphragm material.

  3 and 4 show the ultrasonic transmission performance of the diaphragm (polyester and quartz) based on this number 1. As can be understood from this characteristic graph, the ultrasonic permeability varies depending on the material of the diaphragm, and among these, a thickness having a high transmittance may be appropriately selected.

  FIG. 5 shows the ultrasonic transmittance and the number of residual particles on the substrate. As can be understood from this graph, when a diaphragm having a transmittance of 80% or more is used, ultrasonic energy is transmitted to the cleaning liquid without deteriorating the ultrasonic transmission performance, so that the cleaning effect is further enhanced. I understand.

  In the cleaning head 11, the ultrasonic vibrator 14 is held on the ceiling by the SUS partition wall 13, and the ultrasonic vibrator 14 is connected to the power supply 15. An acoustic lens 16 is disposed on the lower surface of the ultrasonic transducer 14. The cleaning head 11 is filled with the ultrasonic wave propagation liquid B.

  Further, a cooling device 17 is attached to the cleaning head 11, and this cooling device 17 communicates with the cleaning head 11 through a pipe 17a, and the ultrasonic wave propagation liquid B is circulated and cooled.

  A cover 18 is formed at the tip of the cleaning head 11 so as to cover the tip. A slit 19 is formed in the bottom wall of the cover 18. The length of the slit 19 is longer than the width of the substrate A.

  The cleaning liquid supply unit 20 includes a cleaning liquid storage tank 21. The cleaning liquid storage tank 21 is connected to the cover 18 by a cleaning liquid supply pipe 22, and the cover 18 is connected to the cleaning liquid storage tank 21 by a cleaning liquid return pipe 23.

  The cleaning liquid storage tank 21 is connected to a cleaning liquid generator 24 through a pipe 24a. Further, a microbubble generator 25 is disposed in the cleaning liquid storage tank 21, and the microbubble generator 25 is connected to a gas supply source 26 through a pipe 25a.

  In the cleaning liquid supply unit 20, the cleaning liquid deaerated by the degassing membrane module in the cleaning liquid generator 24 is supplied to the cleaning liquid storage tank 21, and is also supplied from the gas supply source 26 in the cleaning liquid storage tank 21. The generated gas is generated in a microbubble state by the microbubble generator 25 and supplied into the cleaning liquid. Therefore, microbubbles are dissolved in the cleaning liquid supplied to the cleaning liquid supply pipe 22. Note that an air vent 27 is disposed in the cleaning liquid return pipe 23.

  The substrate transport unit 30 includes a transport unit 31 such as a belt conveyor, which is disposed along the cleaning liquid supply pipe below the cleaning liquid supply pipe 22. The substrate A is transported by the transport unit 31. It is conveyed so as to cross the lower part of the slit 19 of the cleaning head 11.

  In the ultrasonic cleaning device 1 configured as described above, the ultrasonic transducer 14 is vibrated in the ultrasonic generator 10 to generate ultrasonic waves. This ultrasonic wave is focused by the acoustic lens 16, transmitted to the diaphragm 12 via the ultrasonic wave propagation liquid B, passes through the diaphragm 12 and is irradiated into the cover 18.

  On the other hand, the cleaning liquid is supplied from the cleaning liquid storage tank 21 into the cover 18 via the cleaning liquid supply pipe 22 by a pump (not shown). A part of the cleaning liquid is supplied linearly from the slit 19 onto the substrate A.

  The cleaning liquid supplied onto the substrate A is irradiated with linear ultrasonic waves that have passed through the diaphragm 12, and contaminants on the substrate A are removed by the ultrasonic waves and the microbubbles in the cleaning liquid.

  In the above embodiment, the cleaning head 11 is disposed above the movement range of the substrate A and the cleaning liquid is supplied from above the substrate A. However, the cleaning head 11 is disposed below the substrate and the cleaning liquid is supplied to the substrate. The substrate can be supplied to the lower surface of the substrate for cleaning, and the substrate can be cleaned from both.

  It is also possible to carry the substrate obliquely or vertically and position the tip of the cleaning head 11 so as to face the surface of the substrate.

1 is a cross-sectional perspective view conceptually showing an ultrasonic cleaning apparatus according to an embodiment of the present invention. Schematic diagram showing the ultrasonic cleaning apparatus shown in FIG. Graph showing ultrasonic transmission characteristics of polyester membrane Graph showing the ultrasonic transmission characteristics of quartz diaphragm Graph showing the ultrasonic transmittance and the number of residual particles on the substrate

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic cleaning apparatus, 10 ... Ultrasonic generator, 11 ... Cleaning head, 11a ... Opening, 12 ... Diaphragm, 13 ... Septum, 14 ... Ultrasonic vibrator, 15 ... Power supply, 16 ... Acoustic lens, 17 ... Cooling Equipment: 17a ... Pipe, 18 ... Cover, 19 ... Slit, 20 ... Cleaning liquid supply section, 21 ... Cleaning liquid reservoir, 22 ... Cleaning liquid supply pipe, 23 ... Cleaning liquid return pipe, 24 ... Cleaning liquid generator, 24a ... Pipe, 25 ... Microbubble generator, 25a ... pipe, 26 ... gas supply source, 27 ... air vent, 30 ... substrate transport unit, 31 ... transport means, A ... substrate, B ... ultrasonic wave propagation liquid

Claims (4)

  An opening is formed at the tip, and the opening is covered with a diaphragm having ultrasonic permeability, an ultrasonic transducer is disposed in the upper part of the inside, and an ultrasonic wave propagating liquid is filled inside to constitute a cleaning head, A cover is disposed so as to cover the tip of the cleaning head, a slit is formed in the bottom wall of the cover, and a cleaning liquid is supplied to a space defined by the cover and the tip of the cleaning head, An ultrasonic cleaning apparatus, wherein the cleaning liquid is supplied to the surface of an object to be cleaned from the slit while irradiating ultrasonic waves from an ultrasonic vibrator.   The ultrasonic cleaning apparatus according to claim 1, wherein a tip of the cleaning head is formed in a tapered shape so that a cross section in the traveling direction of the cleaning object becomes narrower toward the tip.   The ultrasonic cleaning apparatus according to claim 1, wherein the diaphragm has an ultrasonic transmittance of 80% or more. The ultrasonic cleaning apparatus according to any one of claims 1 to 3, wherein the cleaning head is disposed to face both surfaces of the object to be cleaned so as to simultaneously clean both surfaces of the object to be cleaned.

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