JPH04314333A - Cleaning device - Google Patents

Abstract

PURPOSE:To obtain an ice-jet cleaner which is small in size and efficient and facilitates control of the particle diameters of ice. CONSTITUTION:Spray of fine particles of water is formed by a double-fluid nozzle 1 and liquefied nitrogen spray is formed by liquefied nitrogen spouting nozzle 2 adjacent to the nozzle 1. The water spray and the liquefied nitrogen spray are mixed in a freezing tower 3 to produce fine particles of ice and the particles are spouted against an object 30 to be washed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus, and more particularly to an apparatus for cleaning an object by applying microscopic ice to the object.

0002

2. Description of the Related Art As semiconductors become more highly integrated, demands on cleaning techniques are also becoming more severe. Along with this, various cleaning methods have been proposed and put into practical use. Among them, a new cleaning device has recently been proposed, which cleans by applying microscopic ice to the wafer, etc. It is used for cleaning filtered membranes, etc.

[0003] Figure 2 is from the literature (Mitsubishi Electric Technical Report, VOL63).
, No. 11, 1989, P984-987). In the figure, 10 is a high-pressure spray nozzle, 2 is a liquid nitrogen nozzle, 3 is a hopper,
4 is an ice transport pipe, 5 is an ejector, 6 is an ice injection nozzle, 7 is a water nozzle, 23 is a water spray, and 30 is an object to be cleaned, such as a silicon wafer. Further, A, B, and C indicate materials to be supplied to this apparatus, where A is pure water, B is liquid nitrogen, and C is gaseous nitrogen.

The conventional ice cleaning apparatus is constructed as described above, in which pure water is atomized in the hopper by the high-pressure spray nozzle 10 attached to the upper part of the hopper 3, and the droplets are sent from the liquid nitrogen nozzle 2 to the hopper. Microscopic ice is created by cooling and freezing with liquid nitrogen supplied inside. The ice and vaporized nitrogen are sucked by the ejector 5 and sprayed from the ice injection nozzle 6 toward the object 30 to be cleaned, thereby cleaning the object. During cleaning, pure water is flowed from the water nozzle 7 onto the surface of the object to be cleaned, thereby increasing the cleaning effect.

[0005]

The ice cleaning apparatus described above has various features compared to conventional cleaning methods. For example, it has a high cleaning effect and uses only materials (water and nitrogen) that have no impact on the environment. However, there are some problems with the equipment, especially the ice maker, and improvements are desired.These problems are as follows.

(1) Conventional ice cleaning equipment uses high-pressure spray nozzles to atomize water, so the particle size of the ice produced is usually limited to a few tens of microns, and ice smaller than this cannot be produced. Can not. This limits cleaning of narrow gaps and cleaning of objects with low hardness, and it is desired to make ice with smaller ice particles. (2) The only thing that can be controlled with a high-pressure spray nozzle is the supply water pressure, and it is difficult to independently control the spray amount and droplet diameter, and there is no flexibility in operating conditions. (3) When creating water particles of several tens of microns with a high-pressure spray nozzle, the spray angle becomes large. Therefore, it becomes necessary to increase the diameter of the hopper, which in turn increases the floor space occupied by the apparatus. (4) The heat exchange efficiency between the atomized droplets sprayed by the high-pressure spray nozzle and liquid nitrogen is low, which also causes the hopper to be large. There is also a possibility that liquid nitrogen will not be used effectively for freezing water. This invention was made to solve these problems, and it is possible to change the particle size of ice, make smaller ice particles, have a small cross-sectional area of the ice making section, and produce ice with high freezing efficiency. The purpose is to provide a cleaning device.

[0007]

[Means for Solving the Problems] A cleaning device according to the present invention atomizes water using a two-fluid nozzle, cools the water droplets to form ice particles, and applies the particles to an object to be cleaned. It is something. Further, by mixing the spray from the two-fluid nozzle with the liquid nitrogen spray from a liquid nitrogen injection nozzle installed adjacent to the two-fluid nozzle, water droplets are frozen to obtain minute ice particles. It is.

[0008]

[Operation] By using a two-fluid nozzle to atomize water as described above, it is possible to change the ice particle size, and smaller ice particles can be made. Furthermore, the spray generated from the two-fluid nozzle is considerably thinner than the spray from the high-pressure spray nozzle, so the cross-sectional area of the ice-making section can be reduced. Moreover, by spray-mixing the two-fluid nozzle spray and the liquid nitrogen spray, heat exchange can be promoted and freezing efficiency can be increased.

[0009]

[Embodiment] Fig. 1 is a configuration diagram showing an embodiment of the present invention, in which 1 is a two-fluid nozzle, 2 is a liquid nitrogen spray nozzle, and 3 is a liquid nitrogen spray nozzle.
is a freezing tower, and the others are the same as in a conventional ice cleaning device. The operation of the ice cleaning device configured as described above will be explained. Pure water A and gaseous nitrogen C are supplied to the two-fluid nozzle 1, and water is atomized by shear force in the gaseous nitrogen jet to form a jet 21 containing water droplets. Here, other gas such as air may be used instead of gas nitrogen. The size of water droplets that can be created with a two-fluid nozzle ranges widely from about a few microns to several hundred microns, and the particle size depends on the amount of water supplied.
The supply gas pressure (corresponding to the supply gas flow rate) can be controlled by control means (not shown).

A plurality of liquid nitrogen injection nozzles 2 are attached to the upper part of the freezing tower 3 so as to surround the two-fluid nozzle 1, from which liquid nitrogen B is injected. The injected liquid nitrogen causes instantaneous evaporation (flashing), and as a result, the liquid nitrogen itself becomes atomized to form a mixed spray 22 of liquid nitrogen and gaseous nitrogen, similar to the spray from a two-fluid nozzle. The jets have a property of attracting each other, so that the spray 21 from the two-fluid nozzle and the spray 22 from the liquid nitrogen injection nozzle quickly mix and exchange heat. The heat exchange causes the water droplets to freeze and become ice particles. The ice particles pass through the ice transport pipe 4 and are ejected from the ice injection nozzle 6 toward the object to be cleaned 30 by the driving force of the ejector 5. In the above explanation, the case where liquid nitrogen is used as the refrigerant has been explained, but the freezing of water droplets may be done by other methods, and the injection of ice can be performed without using an ejector, for example, by setting the internal pressure of the cooling tower to a high level, It may also be used to inject.

[0011]

[Effects of the Invention] Since the present invention is constructed as described above, it produces the following effects. Since a two-fluid nozzle is used to atomize water, small droplets can be produced relatively easily, and the particle size can also be easily controlled. Furthermore, since the spray from the two-fluid nozzle is thinner than that from the high-pressure spray nozzle used in conventional ice cleaning equipment, the cross-sectional area of the frozen part can be reduced, which helps miniaturize the equipment. Furthermore, if a liquid nitrogen nozzle is installed adjacent to a two-fluid nozzle to perform spray mixing, rapid heat exchange can be achieved, so that the amount of liquid nitrogen used can be reduced and the freezing tower can be downsized.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an ice cleaning device showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional ice cleaning device.

[Explanation of symbols]

1 Two-fluid nozzle 2 Liquid nitrogen inlet or liquid nitrogen spray nozzle 3
Hopper or freezing tower 4 Ice transport pipe 5 Ejector 6 Ice injection nozzle 7 Water nozzle 10 High-pressure spray nozzle 21 Two-fluid nozzle spray 22 Liquid nitrogen spray 23 High-pressure spray nozzle spray 30 Item to be cleaned A Pure water B Liquid nitrogen C Gas nitrogen

Claims (2)

[Claims] 1. A cleaning device comprising: means for freezing water particles formed by a two-fluid nozzle; and means for spraying ice particles produced by the means. 2. A liquid nitrogen injection nozzle is provided adjacent to the two-fluid nozzle, and two-fluid spray from the two-fluid nozzle;
The cleaning device according to claim 1, wherein the liquid nitrogen spray is mixed.