JPS59150584A - Ultrasonic washing method and apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to an ultrasonic cleaning method and apparatus.

As is well known, the ultrasonic cleaning method is used for machining parts.

It is used in various fields such as glass processing parts.

However, in conventional ultrasonic cleaning apparatuses, the mainstream method is to apply ultrasonic vibrations to a cleaning liquid in a cleaning tank, and to place the object to be cleaned into the ultrasonicly vibrated cleaning liquid.

However, as a result of studies conducted by the present inventors, it has been found that this method has the following drawbacks. That is, in the conventional method, foreign matter removed from the object to be cleaned by ultrasonic force is present in the cleaning liquid. For this reason, the removed foreign matter may re-act on the object to be cleaned, causing damage to the object if it collides violently, or causing contamination if the foreign matter in the removed cleaning liquid re-adheres to the object to be cleaned. Therefore, it is not suitable as a cleaning method that requires high cleanliness.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ultrasonic cleaning method and an apparatus therefor that can clean an object to a high degree of cleanliness without damaging the object.

The present invention will be explained below with reference to Examples.

The drawing is a principle sectional view showing the main parts of an ultrasonic cleaning apparatus for cleaning both sides of a semiconductor thin film (wafer) according to an embodiment of the present invention. A wafer 1, which is an object to be cleaned, is placed on a round belt 4 hooked around a drive pulley 2 and three driven pulleys 3, and is conveyed by the rotation of the drive pulley 2. The drive pulley 2 is rotated by a motor 5. Further, a cleaning section is provided in the round belt movement area. In this cleaning section, a cleaning A station 7 having a jet type cleaning liquid supply mechanism 6 and a cleaning B stage end 8 are arranged along the moving direction of the wafer 1. In the jet type cleaning liquid supply mechanism 6, a lifting element 9 and a lower vibrator 10 are disposed above and below the round belt 4. Further, these transducers 9 and 10 are configured to oscillate ultrasonic waves by an ultrasonic oscillation power supply section 11.

Further, both the vibrators 9 and 10 are configured such that clean cleaning liquid 14 is jetted out through a filter 13 from flow holes 12 provided in each part. When Ueno 1 is moved by the round belt 4, cleaning 91 is ejected from the flow hole 12 at the cleaning A station 7 and the cleaning B station 8.
4, both sides (upper and lower surfaces) and the surrounding surface are vigorously cleaned. At this time, the cleaning liquid 14 is ultrasonically vibrated at a constant frequency by the upper and lower vibrators 9 and 10 to enhance the cleaning effect. In addition, washing A station 7 and washing B
The stations 8 each vibrate ultrasonic waves at different frequencies. When the frequency is low, foreign particles with a large diameter can be cleaned and removed, and as the frequency becomes high, foreign particles with a small diameter can be cleaned and removed. Therefore, cleaning A station 7 vibrates at a low frequency, for example 28KH2, and cleaning B station 8 vibrates at a high frequency, for example 4KH2.
Vibrate at 00 to 800KHz.

On the other hand, the cleaning liquid involved in cleaning is collected by a funnel-shaped drain cover 15 of the discharge mechanism, and is discharged to the outside from a discharge port 16.

Next, the ultrasonic cleaning method will be explained. When a wafer 1, which is an object to be cleaned, is set on the round belt 4, the round belt 4 is rotated by the motor 5, and the wafer 1 is transported to and set at the cleaning A station 7.

When the wafer 1 is set in the cleaning A station 7, the cleaning liquid 14, which is cleaned by the filter 13 and vibrates ultrasonically as described above, is supplied to both sides of the wafer 1, and both sides of the wafer 1 are cleaned by the jet force and ultrasonic force. washed at the same time.

In the cleaning A stage 1-7, a low range of ultrasonic frequency is applied to remove large foreign matter adhering to both sides of the sea urchin.

When the cleaning at the cleaning A station 7 is completed, the wafer 1 is again conveyed by the round belt 4 to the cleaning B station 8 and set.

In the cleaning B stage controller 8, both surfaces of the wafer 1 are cleaned in the same manner as in the cleaning A stage controller 7 described above. In the cleaning B station 8, ultrasonic waves having a higher frequency than that in the cleaning A station 7 are applied to remove minute foreign matter that could not be removed in the cleaning A station 7.

As described above, according to the present invention, when cleaning a wafer using ultrasonic vibration, cleaning is performed in two cleaning stages with different vibration frequencies, so that even small to large foreign particles can be cleaned and removed. can do. Further, a clean cleaning liquid is always supplied in the form of a jet stream, and foreign matter detached from the wafer 1 is discharged without coming into contact with the wafer 1 again. As a result, the detached foreign matter does not violently collide with the wafer 1, so that the wafer surface is not damaged.

Furthermore, since re-adhesion of foreign matter can be prevented, cleaning can be performed with a high degree of cleanliness. Further, in the present invention, cleaning time is shortened because cleaning liquid is supplied by a jet flow and ultrasonic cleaning with different frequencies is used. Furthermore, since the device of the present invention has a simple mechanism, it is possible to downsize the device.

Note that the present invention is not limited to the above embodiments. That is,
The cleaning effect may be further increased by increasing the number of cleaning stations or by making the vibration directions intersect, such as laterally, even in the same cleaning station.

[Brief explanation of drawings]

The drawing is a schematic sectional view showing essential parts of an ultrasonic cleaning device according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Wafer, 4... Round belt, 6... Jet type cleaning liquid supply mechanism, 7... Cleaning A station, 8...
Cleaning B station, 9... Upper root driver, 10... Lower vibrator, 11... Ultrasonic oscillation power supply section, 13... Filter, 14... Cleaning liquid, 15... Drain cover , 16
···Vent.

Claims (1)

[Claims] 1. An ultrasonic cleaning method characterized by ultrasonically cleaning a moving object by supplying and acting on a cleaning liquid that has been ultrasonically vibrated from a plurality of directions on the object to be cleaned. . 2. The ultrasonic cleaning method according to claim 1, wherein the frequency of the ultrasonic vibration is different in each region along the moving direction of the object to be cleaned. 3. a transport mechanism for moving the object to be cleaned; at least one jet-type cleaning liquid supply mechanism for supplying clean cleaning liquid vibrated by an ultrasonic vibrator from a plurality of directions to the moving object; An ultrasonic cleaning device comprising: a discharge mechanism for discharging cleaning liquid involved in cleaning. 4. The ultrasonic cleaning apparatus according to claim 3, wherein a plurality of jet type cleaning liquid supply mechanisms are provided, and the ultrasonic vibrator of each cleaning liquid supply mechanism is different for each jet type cleaning liquid supply mechanism. .