JP3355460B2 - Cleaning method and apparatus with solid argon - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing or cleaning deposits on the surface of an article with solid argon comprising fine particles.

[0002]

2. Description of the Related Art As a means for removing and cleaning dirt and the like adhering to the surface of an article, it is common to use a cleaning liquid. Has been proposed for injecting water onto the surface to be cleaned.

[0003] For example, the invention described in Japanese Patent Application Laid-Open No. 61-15749 involves removing dry matter from a surface to be cleaned by colliding dry ice particles as a cleaning agent with the surface to be cleaned. In addition, the invention described in Japanese Patent Application Laid-Open No. HEI 1-207182 discloses a method of cleaning a semiconductor wafer, in which ultrapure water is conventionally sprayed onto a surface to be cleaned, and the disadvantage of brushing is eliminated. A method has been proposed in which fine frozen particles are formed, and the particles are sprayed onto a surface to be cleaned to be cleaned.

[0004]

The method of using the above-mentioned dry ice particles as a cleaning agent and the method of using ultrapure water as fine frozen particles and using the same as a cleaning agent also require separate cooling to obtain cleaning particles. Liquid nitrogen is used as a source, and this liquid nitrogen is naturally vaporized and consumed. In both methods, carbon dioxide and ultrapure water, which are the raw materials for the particles,
It is consumed only for cleaning purposes without being collected after processing.

The present invention has been proposed in view of the above circumstances. For example, in the field of semiconductor industry,
Although a large amount of nitrogen gas and argon gas are used, it is based on the finding that an advantageous system can be obtained by organically combining the consumed gas and the cleaning step. That is, generally, high-purity nitrogen and argon are produced by an air separation device using a cryogenic separation method. In addition, since it is advantageous to carry this kind of gas in a liquid state, it is necessary to effectively use the cold of these liquefied gases for cost reduction.

Accordingly, the main object of the present invention is to provide nitrogen,
A method and apparatus for cleaning with solid argon that has an air separation device that produces argon in a liquid state, or that is consumed in a liquid state and consumes a large amount of the above gas, is conveyed and stored in a liquid state, and all of which are consumed in a gaseous state. Is to provide.

[0007]

The present invention SUMMARY OF] In order to achieve the above object, after the liquid argon was allowed supercooling by heat exchange with liquid nitrogen, vacuum, fine <br/> small by that allowed to ejection Generates solid argon particles and generates the fine solid particles
The argon particles by ejecting force those characterized that you clean the surface by blowing on the surface of the object to be cleaned.

Further, according to the present invention, a liquid argon storage tank and a liquid nitrogen storage tank are provided, respectively, and the stored liquid argon and the stored liquid nitrogen are respectively led to a heat exchanger to exchange heat and supercool the liquid argon. If, fine that is Rutotomoni generated to produce a fine solid argon particles supercooled liquid argon allowed vacuum ejected at a sputtering week
The heat with the solid argon particles characterized in that a means for cleaning spraying on the surface of the object to be cleaned by jetting force, further, to this, to supply the nitrogen gas to derive the said heat exchanger to the supply line Means for recovering liquid nitrogen derived from the exchanger in the liquid nitrogen storage tank, and recovering liquid argon derived from the sputtering box to the liquid argon storage tank, and also recovering most of the argon gas by reliquefaction with liquid nitrogen. And means for performing the operation.

[0009]

[For work invention, the I Ri liquids argon over如rather liquids nitrogen subcooled, which solidified under reduced pressure jetting
Since argon particles are used as a cleaning agent as they are, they are particularly suitable for the semiconductor field. Further, since most of the used gas is recovered, it can be implemented without waste.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. In FIG. 1, reference numeral 1 denotes a well-known air separation apparatus for separating air into oxygen, nitrogen, and argon by cryogenic separation to collect nitrogen and argon. The liquid nitrogen collected in the air separation device 1 is introduced and stored in a liquid nitrogen storage tank 3 from a pipe 2, most of the liquid nitrogen is carried out by a lorry, and a part is vaporized from a pipe 4 through an evaporator 5. The gas is supplied to the nitrogen gas supply line via the pipe 6 and consumed.

The liquid argon collected by the air separation device 1 is introduced and stored in a liquid argon storage tank 8 through a pipe 7, most of the liquid argon is carried out to a lorry similarly to the liquid nitrogen, and a part of the evaporator 10 is supplied through a pipe 9. And is supplied to an argon gas supply line via a pipe 11 and consumed. The nitrogen gas collected by the air separation device 1 is led out of the pipe 12 and compressed to a desired pressure, and then consumed through the nitrogen gas supply line 6.

Next, reference numeral 13 denotes a cleaning device, the details of which will be described later with reference to FIG. 2. Liquid nitrogen for subcooling liquid argon is taken out of the liquid nitrogen storage tank 3 via a pipe 14 and supplied. The nitrogen supplied to the cleaning device 13 and in a gas-liquid mixed state is taken out from the pipe 15, introduced into the flash bottle 16 and separated into gas and liquid, and the nitrogen gas is sent to the nitrogen gas supply line via the pipe 17. Can be On the other hand, the liquid nitrogen separated by the flash bottle 16 is taken out from the bottom thereof into a tube 18 and is collected in the liquid nitrogen storage tank 3 via a tube 19.

Liquid argon, which is a source of fine particles in the cleaning device 13, is supplied from the liquid argon storage tank 8 through a pipe 20, and the argon vaporized in the cleaning device 13 is filtered through a pipe 21 through a filter 22. To remove impurities. Next, the pre-cooler 2
After passing through 4 and being liquefied by liquid nitrogen in a reliquefaction unit 25, it is collected in the liquid argon storage tank 8 via a pipe 26. The reliquefier 25 is supplied with liquid nitrogen in the liquid nitrogen storage tank 3 via a pipe 27 to condense and liquefy the argon gas, and the vaporized nitrogen is introduced into the precooler 24 through a pipe 28 and After pre-cooling the gas, the gas is joined to the nitrogen gas supply line 6 through the pipe 29.

After the cleaning operation is completed in the cleaning device 13, the still liquid argon is led out to the pipe 30 and then introduced into the filter 31 to remove impurities. Next, the gas is introduced into the flash bottle 33 through the pipe 32 and separated into gas and liquid. Among them, the argon gas is combined with the argon gas supply line 11 through the pipe 34. On the other hand, the separated liquid argon is supplied from the bottom of the flash bottle 33 to the pipe 35.
And collected in the liquid argon storage tank 8.

Next, FIG. 2 shows an embodiment of the cleaning device 13, and the same parts as those in FIG. 1 are indicated by the same reference numerals. In FIG.
The liquid argon led to zero is supplied to each of the plurality of argon solidification heat exchangers 50 via the branch pipe 51. On the other hand, the liquid nitrogen drawn out from the liquid nitrogen storage tank 3 to the pipe 14 is supplied to the argon-solidifying heat exchangers 50 via the branch pipes 52, and heat exchange is performed in each of the heat exchangers 50. By this heat exchange, liquid argon is supercooled by liquid nitrogen having a lower boiling point,
The supplied liquid nitrogen is then collected by each branch pipe 53 for discharge, reaches the pipe 15 in a gas-liquid mixed state, and is consumed or recovered by the above-described process.

The liquid argon supercooled in each of the heat exchangers 50 then reaches a sputtering box 55 connected to the pipe 54 through a jet pipe 54, and is sprayed under reduced pressure to form fine solid particles. Argon is produced. In the sputtering box 55, for example, a conveyor 56 that moves from the entrance end to the exit end is provided.
The surface of the object to be cleaned 57 on the surface 6 is sprayed with a group of fine solid argon particles ejected by the ejection power from the ejection pipe 54 during the moving process or during the intermittent movement.

The dirt, impurities, and the like adhering to the surface of the object to be cleaned 57 are sprayed with the fine solid argon, and the impact and the surface tension when the solid argon liquefies after the spraying are applied. Washed.

Next, out of the fine solid argon which has completed the cleaning action, the vaporized component is taken out from the tube 21, and the liquefied argon is collected from the bottom of the sputtering box 55 by an appropriate means, and then collected in the tube 30. It is taken out and consumed or collected by the means described above.

In the above embodiment, the air separation device 1 and the cleaning device 13 are provided side by side, and the liquid argon and liquid nitrogen used in the cleaning device 13 are collected by the air separation device 1. The present invention can be implemented even when 1 is not provided. That is, liquid argon or liquid nitrogen produced in a separate air separation device is supplied to the liquid argon storage tank 8 and the liquid nitrogen storage tank 3 by a lorry, so that the same effect as in the above embodiment can be obtained.

Therefore, a user who consumes a large amount of nitrogen gas and argon gas usually transports and stores these gases in a liquid state and vaporizes and uses them as a transportation means. It can be easily implemented by providing the gas recovery means shown in the example.

[0021]

Since the present invention uses solid argon particles as a cleaning agent, the present invention is particularly suitable for cleaning articles that do not want to be activated, such as semiconductor substrates. Further, the cleaning effect is high not only due to the collision of the fine particles but also to the surface tension effect when the solid argon is liquefied.

Further, since the argon gas used for cleaning and the nitrogen gas as a cold source are collected together, there is no waste.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of the present invention.

FIG. 2 is a schematic view showing one embodiment of the cleaning apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air separation apparatus, 3 ... Liquid nitrogen storage tank, 5, 10 ... Evaporator, 8 ... Liquid argon storage tank, 13 ... Cleaning apparatus, 16, 3
3 ... Flash bottle, 22, 31 ... Filter, 24
... Pre-cooler, 25 ... Reliquefier, 50 ... Heat exchanger for solidifying argon, 54 ... Spouting tube, 55 ... Sputtering box, 56 ...
Conveyor, 57: object to be cleaned

Claims (3)

(57) [Claims] The method according to claim 1] Liquid Argon After allowed supercooling by heat exchange with liquid nitrogen, vacuum, depending on the allowed to ejection
Generate infinitesimal solid argon particles, generated fine solid
Cleaning method according to the solid argon which is characterized that you clean the surface by blowing on the surface of the object to be cleaned by jetting force argon particles. Wherein provided liquid argon reservoir and the liquid nitrogen storage tank, respectively, which stored liquid argon and stored liquid nitrogen
Means allowed to respectively be led to the heat exchanger by heat exchange supercooled liquid argon, fine that is Rutotomoni generated to produce a fine solid argon particles supercooled liquid argon allowed vacuum ejected at a sputtering week Solid argon particles
Cleaning apparatus according to the solid argon, characterized in that a means for cleaning spraying on the surface of the object to be cleaned by jetting force element group. 3. A nitrogen gas supplied from the heat exchanger is supplied.
The liquid nitrogen supplied to the line and led out of the heat exchanger
Means for recovering nitrogen in the liquid nitrogen storage tank;
Store the liquid argon from the ring box
Most of the argon gas is converted to liquid nitrogen while collecting in the tank.
And a means for reliquefaction and recovery.
The apparatus for cleaning with solid argon according to claim 2 .