JP-7854883-B2 - Washing tank, washing system, and washing method

JP7854883B2JP 7854883 B2JP7854883 B2JP 7854883B2JP-7854883-B2

Inventors

松下昌嗣
斉藤正広
星子貴広
中谷典靖
谷藤保

Assignees

株式会社ダルトン

Dates

Publication Date: 20260507
Application Date: 20220714

Claims (7)

An inner tank having sides and a bottom, A support for at least one object to be cleaned, disposed within the inner tank, A flow nozzle is provided on the side of the inner tank, positioned below the support, and is configured to supply cleaning liquid for cleaning the object to be cleaned into the inner tank, and to generate a swirling flow of cleaning liquid that flows circumferentially in the area inside the inner tank where the object to be cleaned is immersed , within the plane visible when the inner tank is viewed from above . A discharge port is provided in the vicinity of the side portion of the bottom of the inner tank, or in the portion of the side portion adjacent to the bottom, and is configured to discharge the cleaning liquid. An ultrasonic oscillator provided at the bottom of the inner tank, A washing tank having
The washing tank according to claim 1, wherein the multiple flow nozzles are arranged at the same height with respect to the height of the inner tank.
The cleaning tank according to claim 1 or 2, further comprising an outer tank for containing cleaning fluid that overflows from the inner tank.
A method for cleaning at least one object to be cleaned, which is supported by a support located in an inner tank having sides and a bottom, From a flow nozzle provided on the side of the inner tank and positioned below the support, a cleaning liquid for cleaning the object to be cleaned is supplied into the inner tank, and a swirling flow of the cleaning liquid is generated in the area inside the inner tank where the object to be cleaned is immersed , flowing circumferentially within the plane visible when the inner tank is viewed from above . The cleaning liquid is discharged from a discharge port provided in the vicinity of the side portion of the bottom of the inner tank, or in the portion of the side portion adjacent to the bottom. At least one of the following states: when the cleaning fluid is being supplied from the flow nozzle and when the cleaning fluid is being discharged from the discharge port, an ultrasonic oscillator provided at the bottom of the inner tank emits ultrasonic waves. A cleaning method that includes [details omitted].
The cleaning method according to claim 4, wherein the series of processes of emitting ultrasonic waves from the ultrasonic oscillator, stopping the ultrasonic waves, and discharging the cleaning solution from the discharge port are repeated at least once.
A washing tank according to claim 1 or 2, A cyclone-type filter fluidly connected to the flow nozzle of the inner tank, A cleaning system having the following features.
The cleaning system according to claim 6, comprising a pump configured to extract cleaning fluid from the cleaning tank, pass the extracted cleaning fluid through the cyclone filter, and return it to the inner tank.

Description

This invention relates to a cleaning tank for cleaning workpieces such as semiconductor wafers and glass substrates, a cleaning system including the cleaning tank, and a cleaning method using the cleaning system. Generally, in the manufacturing process of semiconductor wafers and glass substrates, cleaning is performed to remove abrasive materials and fragments (hereinafter also referred to as foreign matter) adhering to the wafer. This cleaning is often carried out by immersing the object to be cleaned in a tank containing a cleaning solution. To improve the efficiency of this cleaning, techniques such as generating a vortex in the cleaning solution within the tank or utilizing ultrasound are known. For example, Patent Document 1 describes a technique for generating a swirling flow by supplying a cleaning solution containing microvalves from nozzles placed inside a cleaning tank. Patent Document 2 describes a technique for generating a vortex in the processing solution by using a storage tank with a spiral-shaped wall. Furthermore, Patent Document 3 describes a technique for adjusting the size of the vortex generated inside a processing tank by providing multiple nozzles in the tank. On the other hand, there is also a known technique for improving cleaning efficiency by irradiating substrates and other materials immersed in a cleaning solution with ultrasound (see, for example, Patent Documents 4-5). Japanese Patent Publication No. 2019-201069Japanese Patent Publication No. 2003-282512Japanese Patent Publication No. 2009-239061Japanese Patent Publication No. 2020-098843Japanese Patent Publication No. 2016-115373 This is a schematic diagram of the cleaning system according to the embodiment.Figure 1 is a schematic front view of the cleaning tank included in the cleaning system.Figure 2 is a schematic side view of the washing tank.Figure 2 is a schematic top view of the washing tank. Figure 1 is a schematic diagram of a cleaning system according to a preferred embodiment. The cleaning system 10 includes a cleaning tank 12, a storage tank 14 for temporarily storing cleaning fluid from the cleaning tank 12, a cyclone filter 16, a pump 18, and a drain tank 20. The storage tank 14 has a filter 22, such as a metal mesh, for filtering the cleaning fluid discharged from the cleaning tank 12. The pump 18 is configured to extract the cleaning fluid from the storage tank 14, supply it to the cyclone filter 16, and then return the filtered cleaning fluid to the cleaning tank 12 and the storage tank 14. The storage tank 14 has a roughly cylindrical body 26 and a roughly conical bottom 28, and is configured to form a vortex inside due to the cleaning liquid from the cyclone filter 16. This causes the cleaning liquid that has passed through the filter 22 to be discharged towards the pump 18. The drain tank 20 is configured to collect sludge 24 and other materials separated from the cleaning liquid by the cyclone filter 16 and discharge them as drain. Figures 2-4 are front, side, and top views, respectively, showing the schematic configuration of the cleaning tank 12. The cleaning tank 12 comprises a roughly rectangular inner tank 30, an outer tank 32 for receiving cleaning fluid overflowing from the inner tank 30, and an ultrasonic oscillator 36 provided at the bottom 34 of the inner tank 30. While the inner tank 30 and outer tank 32 in the illustrated example are both roughly rectangular, this disclosure is not limited to this; for example, they may be cylindrical. However, given the configuration in which the overflow from the inner tank 30 is received by the outer tank 32, it is preferable, as shown in Figure 4, that both the inner tank 30 and outer tank 32 are roughly rectangular in top view, and that one side of each is adjacent to the other. At least one flow nozzle 40 is provided on the side (side wall) 38 of the inner tank 30, configured to supply cleaning fluid from the cyclone filter 16, etc. A discharge port 44 is provided on the bottom 34 of the inner tank 30, configured to discharge the cleaning fluid. As shown in Figure 4, the discharge port 44 is located either near the side portion 38 of the bottom portion 34 of the inner tank 30, or in a portion of the side portion 38 adjacent to the bottom portion 34. Here, "near the side portion" means, for example, that the distance from the center (or center of gravity) of the bottom portion 34 to the discharge port 44 is 1/2, 2/3, 3/4, or 4/5 of the distance from the center (or center of gravity) of the bottom portion 34 through the discharge port 44 to the side portion 38. A support 46 is placed inside the inner tank 30, and at least one (usually more) objects to be cleaned (workpieces) 48 are supported by the support 46. The workpieces 48 are, for example, disc-shaped semiconductor wafers with a diameter of 100 mm to 200 mm (4 inches to 8 inches), and are heavily soiled, such as Azcut wafers obtained by cutting single-crystal ingots with an internal cutting machine