JPH04203869A - Cleaning device using fine frozen particles - Google Patents

Abstract

PURPOSE:To produce hollow fine frozen particles efficiently and reduce the using amount of refrigerant by a method wherein a mixing vessel, dissolving gas under frozen condition, and a high-pressure tank, pressurizing frozen liquid to a high pressure and cooling it, are provided. CONSTITUTION:Gas is dissolved into frozen liquid such as pure water and the like by the bubbling of the gas such as CO2, O2 and the like in a mixing vessel 9. The frozen liquid is pressurized to the degree of several thousands kg/cm<2> and is cooled by a high pressure tank 10. In this case, the cooling 4s effected to suppress the temperature rise of the frozen liquid which is generated by the pressurization. Next, frozen liquid is sprayed from a sprayer 3 into an ice making unit 1 as fine particles. In this case, molten gas in pulverized frozen liquid (fine liquid drops) is expanded by the fluctuation of a pressure from a high-pressure condition into a normal pressure condition and is cooled. The fine liquid drops are cooled effectively by the cooling due to the molten gas and the cooling due to refrigerant 2 such as liquid nitrogen and the like whereby fine frozen particles 5 of hollow structure can be obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a cleaning device using micro-frozen particles for removing contaminants adhering to a substrate by spraying micro-frozen particles toward the substrate. It is something.

[Prior Art] Fig. 2 shows a conventional cleaning device using micro-frozen particles. In the figure, an ice making section (1) that generates micro-frozen particles is supplied with a cooling medium (2) such as liquid nitrogen for cooling. and a spray nozzle (3) for finely spraying pure water. (4) is a pressurized tank for applying a constant pressure to pure water, and (5) is fine frozen particles. A spray gun (6) that sprays fine frozen particles toward the substrate and a substrate (7) that is an object to be cleaned such as a semiconductor wafer spray the fine frozen particles (5) toward the substrate (
7) is housed in a cleaning section (8) that performs cleaning.

With the above configuration, a cooling medium (2) such as liquid nitrogen is injected into the ice making section (1) covered with a heat insulating material to cool the inside of the ice making section (1) (approximately -150'c). Next, a liquid to be frozen, such as ultrapure water, is slightly sprayed from the spray nozzle (3). In this case, in order to keep the supply amount of pure water constant, pressurized tank (4)
A constant pressure (approximately 5 kg/cm') is applied to the pure water. The atomized fine droplets of the liquid to be frozen are cooled by a cooling medium (
By heat exchange with 2), it becomes fine frozen particles (5). The injection gun (6) injects the fine frozen particles (5) toward the substrate (7) using one type of ejector using a gas jet. The cleaning section (8) is evacuated, and the contaminants removed from the substrate (A) are discharged to the outside of the cleaning section (8).

[Problems to be Solved by the Invention: Conventional cleaning devices using fine frozen particles generate fine frozen particles only by heat exchange between fine droplets of the liquid to be frozen and a cooling medium.

This method has problems in that the production efficiency of finely frozen particles is very poor and a large amount of cooling medium is required.

Furthermore, the cleaning of the object to be cleaned is carried out by spraying fine frozen particles and colliding with the surface of the object to be cleaned, and depending on the material and shape of the surface, the impact force may cause damage. This is highly dependent on the hardness, mass, injection speed and injection angle of the finely frozen particles.

This invention was made to solve the above-mentioned problems, and it improves the production efficiency of finely frozen particles, reduces the amount of cooling medium used, and reduces damage to the objects to be cleaned during cleaning. The purpose of this invention is to obtain a cleaning device using fine frozen particles.

"Means for Solving the Problems" A cleaning device using finely frozen particles according to the present invention includes a mixer for dissolving scum in a liquid to be frozen such as pure water, and a high-pressure tank for pressurizing the liquid to be frozen to a high pressure and cooling it. , an ice-making section that converts the liquid to be frozen into fine droplets to produce hollow fine frozen particles, and a cleaning section that sprays the fine frozen particles onto the object to be cleaned.

[Function] In this invention, in order to generate finely frozen particles, particles are dissolved in a liquid to be frozen, and the liquid to be frozen is formed into fine droplets under high pressure to form hollow finely frozen particles. Therefore, the dissolved scum in the liquid to be frozen expands during the transition from high pressure to normal pressure, forming hollow fine droplets, and cooling the droplets.

[Embodiment] FIG. 1 shows an embodiment of the present invention, and in the figure, (9
) is a mixer for dissolving gas in the liquid to be frozen, (1
0) is a high-pressure tank that pressurizes the liquid to be frozen to high pressure and cools it.

Other than that, the same symbols as in Fig. 2 indicate the same parts.
The explanation will be omitted.

Next, the operation will be explained. The liquid to be frozen such as pure water is dissolved by bubbling of CO2, O, etc. in the mixer (9). Next, the liquid to be frozen is pressurized to approximately several thousand kg/cm'' by a high-pressure tank (10) and cooled.The purpose of cooling in this case is to suppress the rise in temperature of the liquid to be frozen caused by pressurization.

Next, the liquid to be frozen is sent to the ice making section (1) from the spray nozzle (3).
Finely sprayed inside. At this time, the dissolved gas in the micronized liquid to be frozen (fine droplets) expands and is cooled due to the change from a high pressure state to a normal pressure state. By cooling with this dissolved gas and cooling with a cooling medium (2) such as liquid nitrogen, the fine droplets are effectively cooled and become fine frozen particles (5) with a hollow structure. Hereinafter, the process of spraying the fine frozen particles (5) onto the substrate (7) to perform cleaning is the same as in the prior art, and therefore the description thereof will be omitted.

[Effects of the Invention] As described above, according to the present invention, a mixer for dissolving gas during freezing and a high-pressure tank for pressurizing and cooling the liquid to be frozen are provided. Frozen particles can be generated efficiently and the amount of refrigerant used can be reduced. In addition, because it becomes a micro-frozen particle or a hollow structure,
The mass is reduced, which has the effect of reducing the load on the object to be cleaned during cleaning.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of an embodiment of the present invention, and FIG. 2 is a front sectional view of a conventional cleaning device using fine frozen particles. (1)...Ice making section, (5)...Fine frozen particles, (7)...
・Substrate (object to be cleaned), (8) ・Cleaning section, (9)
...Mixer, (lO)...High pressure tank. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Masu Oiwa Male trap 2 diagram

Claims (1)

[Claims] A mixer that mixes gas into the liquid to be frozen, a high-pressure tank that pressurizes the liquid to be frozen and cools it, and an ice maker that converts the liquid to be frozen into fine droplets and freezes them to produce fine frozen particles. and a cleaning section that sprays the fine frozen particles towards the object to be cleaned and cleans the object to be cleaned.