JP2007073615A - Cleaning nozzle and cleaning method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning nozzle and a cleaning method using the same, capable of removing a contaminant at a low cost with no damage on an object. <P>SOLUTION: A cleaning nozzle 10 comprises a nozzle body 18 equipped with a cross-sectionally circular divergent part 13 gradually enlarging in flow direction on the lower stream side of a throat 11, and a cleaning liquid supply pipe 21 that discharges a cleaning liquid 20 in the same direction as the flow of a compressed air 15 that is supplied to the nozzle body 18. The discharge opening 22 of the cleaning liquid supply pipe 21 is arranged near the throat 11 away from an inside wall surface 23 of the nozzle body 18, with the compressed air 15 advancing at sonic speed in the throat 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a cleaning nozzle that ejects fine ice particles and supercooled droplets at supersonic speed, and a cleaning method using the same.

Along with the recent miniaturization and multilayering of semiconductor devices and the increase in substrate diameter, there is a demand for a cleaning apparatus that has a low environmental impact and a high cleaning effect. For example, cleaning using ice blasting (ice spraying) As an apparatus, Patent Document 1 discloses that ice particles are generated by spraying water droplets in a container to which liquid nitrogen is supplied, and the ice particles are rapidly applied to the surface of an object to be cleaned (semiconductor wafer, glass substrate, etc.). A wafer cleaning apparatus is disclosed that removes contaminants by collision. Patent Document 2 discloses a cleaning material in which a mixture of water and an organic compound liquid (isopropyl alcohol or the like) having a lower freezing point is cooled below the freezing point of water to form a sherbet-like coexisting solid liquid containing ice particles. A cleaning device is disclosed in which contaminants are removed by jetting a target to be cleaned and causing it to collide. Further, Patent Document 3 discloses a supersonic nozzle including a Laval nozzle to which compressed air is supplied and a small-diameter water hole that is provided on the upstream side surface of the Laval nozzle and supplies cleaning liquid to the Laval nozzle.

JP-A-6-132273 JP 2003-151942 A Japanese Patent Laid-Open No. 10-223587

However, in the invention of Patent Document 1, the particle size of ice particles is relatively large, such as several tens of μm, and has a high cleaning effect, but damages the surface of the object to be cleaned. Since liquid nitrogen and its ancillary facilities are required, there is a problem that costs are increased. Further, in the invention of Patent Document 2, there is a problem that the cost increases because the mixed liquid obtained by mixing water and the organic compound liquid is cooled by a mechanical refrigerator. Further, in the invention of Patent Document 3, the cleaning liquid is accelerated and cooled by the supersonic and low-temperature compressed air passing through the Laval nozzle, and cooled to become ice particles. The ice particles are ejected from the supersonic nozzle, and the object to be cleaned Contaminants adhering to the surface of the nozzle can be removed, but since the water hole is provided on the side surface of the supersonic nozzle, the cleaning liquid is affected by the protruding part of the Laval nozzle and the inner wall surface, and the speed decreases. There was a problem that the cleaning liquid could not be cooled efficiently, the generation of ice particles was reduced, and the ejection range of the ice particles ejected from the supersonic nozzle ejection port was biased.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a cleaning nozzle that can remove contaminants at a low cost and that does not damage an object to be cleaned, and a cleaning method using the same.

A cleaning nozzle according to a first aspect of the present invention that meets the above-described object is a nozzle body that includes a divergent portion that expands in the flow direction on the downstream side of a throat portion having a circular cross-section, and is supplied to the nozzle body. A cleaning nozzle having a cleaning liquid supply pipe for discharging the cleaning liquid in the same direction as the flow of the compressed gas (hereinafter also referred to as compressed gas A),
The discharge port of the cleaning liquid supply pipe is disposed in the vicinity of the throat portion away from the inner wall surface of the nozzle body, and the compressed gas has a sound velocity at the throat portion.

As the compressed gas, air, nitrogen, or the like can be used. The compressed gas is compressed to about 2 to 10 atm so as to be sonic at the throat portion and supplied to the nozzle body. Further, pure water or the like can be used as the cleaning liquid. The compressed gas and the cleaning liquid use materials that do not damage (chemical reaction, etc.) the object to be cleaned. The compressed gas undergoes adiabatic expansion at the divergent portion that expands from the throat portion, further accelerates from the sound speed (about 330 m / sec) to supersonic speed (about 400 to 500 m / sec), and at a low temperature (−60 to -110 ° C).

The cleaning liquid supplied in the flow of the compressed gas is atomized by the collision of the liquid supplied in the high-speed (100 m / sec or more, up to supersonic speed) compressed gas. The atomized cleaning liquid (droplet) is rapidly cooled by a compressed gas cooled to about −60 to −110 ° C. in a divergent portion, and either one of fine ice particles and supercooled droplets or Become both. Here, the supercooled droplet is a droplet cooled to 0 ° C. or lower.

In the cleaning nozzle according to the first aspect of the present invention, it is preferable that the nozzle body has a convergent portion formed on the upstream side of the throat portion to form a convergent portion and a laval nozzle is formed. .
The Laval nozzle has a convergent portion upstream of the throat portion and a divergent portion downstream of the throat portion. Here, the Laval nozzle has a shape that allows the compressed gas to be appropriately adiabatically expanded by the characteristic curve method (HW Lipmann and A. Roshko: “Elements of Gasdynamics”, 1960) to atomize the cleaning liquid and cool it to a low temperature. Designed (analyzed). In the Laval nozzle designed by the characteristic curve method, the compressed gas supplied to the Laval nozzle is subsonic at the convergent part, becomes sonic at the throat part with a small cross-sectional area, and pressure at the divergent part with a large cross-sectional area. Falls and becomes supersonic.

In the cleaning nozzle according to the first aspect of the present invention, a gas supply pipe for supplying another compressed gas (hereinafter referred to as compressed gas B) mixed with the cleaning liquid may be disposed in the cleaning liquid supply pipe.
The component of another compressed gas B supplied from the gas supply pipe may be the same as that of the compressed gas A, and is preferably compressed at a higher pressure than the compressed gas A and discharged at a high speed. The cleaning liquid is mixed with another compressed gas B having a high speed to promote atomization.

In the cleaning nozzle according to the first aspect of the present invention, the discharge port of the cleaning liquid supply pipe is within a range of five times the diameter of the throat portion in the upstream direction and the downstream direction from the center of the throat portion, respectively. It is preferable to arrange.
Here, when the discharge port is arranged on the upstream side from the center of the throat portion with a length of 5 times or more the diameter of the throat portion, the cleaning liquid is discharged into the compressed gas having a low flow rate and a high temperature. For this reason, the particle size of the generated droplets increases, and the cooling efficiency also decreases. In addition, when the discharge port is arranged downstream from the center of the throat part at a length more than 5 times the diameter of the throat part, the distance to the nozzle body outlet (jet port) becomes short, and the droplets It cannot be cooled sufficiently.

In the cleaning nozzle according to the first aspect of the present invention, the nozzle body may include an accelerated cooling section that gradually expands in the flow direction on the downstream side of the divergent section.
In the cleaning nozzle according to the first aspect of the present invention, it is preferable that the temperature and humidity of the compressed gas are adjusted, and the temperature of the cleaning liquid is adjusted.
Here, for example, the compressed gas is adjusted to a temperature of 0 to 40 ° C., preferably 10 to 30 ° C. (about room temperature), and a humidity in terms of dew point temperature of −20 to 0 ° C., preferably −15 to −5 ° C. Is done. The temperature of the cleaning liquid is adjusted to -5 to 30 ° C, preferably 0 to 20 ° C.
In the cleaning nozzle according to the first aspect of the present invention, a rectifying plate that aligns the flow of the compressed gas may be provided upstream of the throat portion.

A cleaning method according to a second aspect of the present invention is directed to supplying a compressed gas from an upstream side of a nozzle body provided with a divergent portion that expands in the flow direction on the downstream side of a throat portion having a circular cross section. A first step of setting the compressed gas to sound velocity at a part;
A second step of discharging the cleaning liquid in the same direction as the flow of the compressed gas supplied to the nozzle body from the discharge port of the cleaning liquid supply pipe disposed in the vicinity of the throat portion away from the inner wall surface of the nozzle body;
The droplets generated by atomizing the cleaning liquid by the compressed gas flow in the divergent section are rapidly cooled to generate a cleaning material consisting of one or both of fine ice particles and supercooled droplets. A third step to perform,
A fourth step of injecting the supersonic cleaning material from the nozzle main body and causing the cleaning object to collide with the object to be cleaned to separate the contaminants on the object to be cleaned;
And a fifth step of sliding the cleaning material on the surface of the cleaning object to remove the peeled contaminants.

In the cleaning nozzle according to any one of claims 1 to 7, since the discharge port of the cleaning liquid supply pipe is disposed in the vicinity of the throat portion separated from the inner wall surface of the nozzle body, the discharged cleaning liquid is disposed on the inner wall surface of the nozzle body. It is difficult to be affected by the boundary layer area formed on the nozzle, and the speed of the cleaning liquid on the inner wall surface of the nozzle body, that is, the atomized liquid droplets, can be prevented and the atomized liquid droplets can be sufficiently accelerated. Can cool to low temperatures.
In particular, in the cleaning nozzle according to claim 2, since the upstream side of the throat portion is reduced in diameter in the flow direction to form a convergent portion and a Laval nozzle is formed, even if the speed of the convergent portion is subsonic, the throat portion Can accelerate to the speed of sound.

In the cleaning nozzle according to claim 3, since the gas supply pipe for supplying another compressed gas B to be mixed with the cleaning liquid is disposed in the cleaning liquid supply pipe, the droplets are atomized to a predetermined particle size. Can do.
In the cleaning nozzle according to claim 4, since the discharge port of the cleaning liquid supply pipe is disposed within a predetermined range, the cleaning liquid is accelerated by the flow of the compressed gas to form fine droplets, and the fine ice particles and A cleaning material comprising either or both of the supercooled droplets can be generated. In addition, the cleaning material is not easily affected by the boundary layer region formed on the inner wall surface of the nozzle body, and the speed reduction on the inner wall surface of the nozzle body can be prevented, and the cleaning material is sufficiently accelerated and cooled to a lower temperature. The

In the cleaning nozzle according to claim 5, since the nozzle main body has an acceleration cooling section that gradually expands in the flow direction on the downstream side of the divergent section, the boundary layer region with the inner wall surface of the nozzle main body In this case, it is possible to sufficiently reduce the speed drop and to sufficiently accelerate the atomized droplets and cool them.
In the cleaning nozzle according to the sixth aspect, since the temperature and humidity of the compressed gas and the temperature of the cleaning liquid are adjusted, the freezing ratio of the droplets can be changed.
In the cleaning nozzle according to claim 7, since the flow straightening plate for aligning the flow of the compressed gas is provided on the upstream side of the throat portion, the pressure loss is reduced, and the compressed gas is smoothly and efficiently supplied to the throat portion. The speed of the compressed gas at the throat portion can be made the speed of sound.

In the cleaning method according to claim 8, since the cleaning material consisting of one or both of fine ice particles and supercooled droplets is injected from the injection port of the nozzle body at supersonic speed and collides with the object to be cleaned. The ice particles melt to become water, the supercooled droplets are instantly released from supercooling to become ice, and the cleaning material that has collided with the object to be cleaned becomes a sherbet and has an excellent cleaning effect. Moreover, since the cleaning material has a sherbet shape, it is easy to slide on the surface of the cleaning object.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory diagram of the cleaning nozzle according to the first embodiment of the present invention, FIG. 2 is a graph showing the relationship between the speed and temperature of the compressed gas in the cleaning nozzle, and FIG. It is explanatory drawing of the washing nozzle which concerns on 2 embodiment.

A cleaning nozzle 10 according to a first embodiment of the present invention will be described with reference to FIG.
The nozzle body 18 of the cleaning nozzle 10 includes a throat portion (throat portion) 11 having a circular cross-section with a minimum tube inner diameter, a convergent portion 12 which is upstream of the throat portion 11 and has a diameter reduced in the flow direction, and a throat It has a Laval nozzle 14 formed by a divergent portion 13 which is downstream of the portion 11 and is expanded in the flow direction. The Laval nozzle 14 has a diameter of the throat portion 11 of, for example, 3 to 10 mm, and the compressed gas supplied to the convergent portion 12 and the divergent portion 13 is appropriately adiabatically expanded and cooled to a low temperature. The shape is designed (analyzed) by the characteristic curve method and processed into the required shape.

Compressed air 15 that is an example of compressed gas A pressurized to 2 to 10 atmospheres (for example, 5 atmospheres) from a compressed gas supply mechanism (not shown) is supplied to the nozzle body 18 upstream of the Laval nozzle 14. A gas supply unit 16 is provided. Further, an acceleration cooling section 17 that gradually increases in diameter in the flow direction is provided on the downstream side of the divergent section 13 of the Laval nozzle 14. Normally, the speed of the fluid supplied into the pipe decreases near the inner wall surface (boundary layer area) of the pipe, but in the case of a pipe of the same diameter, the boundary layer area where the speed decreases near the outlet of the pipe widens. The velocity of the fluid is reduced outside the center of the center. However, the accelerated cooling unit 17 gradually increases in diameter in the flow direction in consideration of the boundary layer region, and the velocity of the compressed air 15 in the boundary layer region formed by the compressed air 15 and the inner wall surface 23 of the nozzle body 18. Since the influence of the reduction is suppressed, a high-speed flow can be sufficiently secured in a wide range even near the outlet (jet 19) of the nozzle body 18.

Here, the nozzle body 18 includes a compressed gas supply unit 16, a Laval nozzle 14, and an acceleration cooling unit 17. Moreover, the compressed gas supply part 16, the Laval nozzle 14, and the acceleration cooling part 17 are each formed, for example with the Teflon (trademark) resin, and are integrated. The nozzle body 18 may be manufactured by being integrally formed. The distance from the center of the throat portion 11 to the injection port 19 at the downstream end of the nozzle body 18 is, for example, 100 to 300 mm, and the compressed air 15 can be sufficiently accelerated.

The compressed air 15 is sent to the compressed gas supply unit 16 after the pressure is adjusted by the compressed gas supply mechanism so that the throat unit 11 has a sound velocity. The compressed air 15 is supplied from the compressed gas supply unit 16 to the convergent unit 12 at a subsonic speed (for example, about 50 m / sec). The compressed air 15 is accelerated by the convergent portion 12, becomes a sound velocity (about 330 m / sec) by the throat portion 11, and further accelerated by the divergent portion 13, for example, about 400 to 500 m / sec (for example, 500 m / sec). It has become supersonic speed. The compressed air 15 is accelerated at the divergent portion 13 to become supersonic and has a temperature of about −60 to −110 ° C. (in the present embodiment, about −110 as shown in FIG. 2). ° C).

Further, the compressed gas supply mechanism is provided with a temperature and humidity adjusting unit (not shown), and the temperature of the compressed air 15 supplied to the compressed gas supply unit 16 is set to 0 to 40 ° C. (for example, normal temperature), for example. For example, it is adjusted to −20 to 0 ° C. (for example, −10 ° C.) in terms of dew point temperature. Further, a rectifying plate 19a is provided on the upstream side of the throat portion 11, the flow of the compressed air 15 is aligned, the pressure loss is reduced, and the compressed air 15 is smoothly supplied to the throat portion 11.

The cleaning nozzle 10 includes a cleaning liquid supply pipe 21 that discharges a cleaning liquid (for example, pure water) 20 in the same direction as the flow of the compressed air 15 supplied into the tubular nozzle body 18. Here, the temperature of the cleaning liquid 20 is adjusted to −5 to 30 ° C. (for example, 25 ° C.). The discharge port 22 of the cleaning liquid supply pipe 21 is located near the throat portion 11 and away from the inner wall surface 23 of the nozzle body 18, for example, the throat portion 11 from the center of the throat portion 11 in the upstream direction and the downstream direction, respectively. It is arranged in a discharge port arrangement position (shown by a two-dot chain line in the figure) 24 that is within a range of a length of 5 times the diameter (for example, 1 time).

Here, the cleaning nozzle 10 converts the compressed air 15 supplied to the compressed gas supply unit 16 into a supersonic and low-temperature flow via the convergent unit 12, the throat unit 11, and the divergent unit 13. The cleaning liquid 20 discharged therein is changed into droplets 30 by the high-speed flow of the compressed air 15, and the droplets 30 are further cooled to form fine ice particles 31 and supercooled droplets (droplets cooled to 0 ° C. or lower). A cleaning material 33 made of either one or both of the cleaning materials 33 is generated, and this cleaning material 33 is jetted from an injection port 19 of the nozzle body 18 onto a cleaning object (for example, a silicon wafer) 35 to collide with the cleaning object 33. 35 is used by being incorporated in a cleaning device (not shown) for removing the contaminant 36 on the surface.

Next, a cleaning method using the cleaning nozzle 10 will be described.
(First step)
First, compressed air 15 having a predetermined pressure (5 atm), temperature (normal temperature), and humidity (dew point temperature conversion −10 ° C.) is supplied from the compressed gas supply mechanism to the compressed gas supply unit 16 of the nozzle body 18. The compressed air 15 is accelerated by the convergent portion 12 whose diameter is reduced in the flow direction of the compressed air 15 to become a sound velocity (approximately 330 m / sec). The compressed air 15 passes through the throat portion 11 and is then accelerated to a supersonic speed (approximately 500 m / sec) by the divergent portion 13 that expands in diameter, and is cooled to approximately −110 ° C. .

(Second step)
Next, the cleaning liquid 20 is discharged in the same direction as the flow of the compressed air 15 from the discharge port 22 of the cleaning liquid supply pipe 21 disposed in the discharge port arrangement position 24.
(Third step)
In the divergent section 13, the cleaning liquid 20 collides with the compressed air 15 due to the high-speed flow of the compressed air 15, thereby generating droplets 30 that are atomized to, for example, about several μm, for example, an average particle diameter of about 7 μm. To do. The droplets 30 are rapidly cooled by the cooled −110 ° C. compressed air 15 in the divergent section 13, and the cleaning material 33 including one or both of the fine ice particles 31 and the supercooled droplets 32 is formed. Generate.

(4th process)
The supersonic cleaning material 33 is sprayed from the injection port 19 of the nozzle body 18 and collides with the cleaning object 35 to separate the contaminant 36 on the cleaning object 35. The cleaning material 33 that has collided with the object to be cleaned 35 is melted into ice particles 31 to become water, and the supercooled droplets 32 are instantly released from supercooling to become ice and become a sherbet. The sherbet-shaped cleaning material 33 has an excellent cleaning effect. Note that the object to be cleaned 35 is not damaged by the ice particles 31 formed from the droplets 30 having an average particle diameter of 7 μm.
(5th process)
Further, the sherbet-like cleaning material 33 slides on the surface of the cleaning object 35 and removes the polluted contaminants 36.

With reference to FIG. 3, the washing nozzle 40 which concerns on the 2nd Embodiment of this invention is demonstrated. The same components as those of the cleaning nozzle 10 are denoted by the same reference numerals, and detailed description thereof is omitted.
The cleaning nozzle 40 is a compressed gas that is an example of another compressed gas B mixed with the cleaning liquid 20 in the cleaning liquid supply pipe 41 that discharges the cleaning liquid 20 in the same direction as the flow of the compressed air 15 supplied into the nozzle body 18. The point from which the gas supply pipe | tube 43 which supplies the air 42 is arrange | positioned differs from the washing nozzle 10. FIG. Accordingly, the droplets 30 can be refined to a predetermined particle size, and by making the droplets 30 finer, the cooling rate is increased, and the cleaning material 33 having a larger proportion of ice particles 31 than the supercooled droplets 32. Can be generated, and the cleaning ability can be improved.

Next, examples carried out for confirming the effects of the present invention will be described. Here, FIG. 4 is a graph showing the average particle size of contaminants that can be removed by the cleaning nozzle.
Nozzle body provided with a Laval nozzle designed by the characteristic curve method with a throat portion of 5 mm, a compressed gas supply unit provided on the upstream side of the Laval nozzle, and an acceleration cooling unit provided on the downstream side of the Laval nozzle and gradually expanding in diameter Inside, a contaminant on the surface of the object to be cleaned was removed using a cleaning nozzle provided with a cleaning liquid supply pipe for discharging the cleaning liquid in the same direction as the flow of the compressed gas.

As a comparative example, the object to be cleaned was similarly cleaned using a supersonic nozzle described in Patent Document 3. As shown in FIG. 4, it was found that when the cleaning material injection speed is the same, finer contaminants can be removed by using the cleaning nozzle of the example. It is understood that this is because the cleaning material produced by the cleaning nozzle of the present invention is fine and is ejected from the cleaning nozzle injection port toward the surface of the object to be cleaned in a supersonic and uniform manner. .

The present invention is not limited to the above-described embodiment, and can be changed without changing the gist of the present invention. For example, some or all of the above-described embodiments and modifications are possible. The case where the cleaning nozzle and the cleaning method of the present invention are configured by combining the above is also included in the scope of the right of the present invention.
For example, in the cleaning nozzle and the cleaning method of the above-described embodiment, compressed air is used as the compressed gas A and another compressed gas B, and pure water is used as the cleaning liquid, but the contaminants are removed without deteriorating the object to be cleaned. For example, nitrogen may be used as the compressed gas, and alcohol may be used as the cleaning liquid. Moreover, although the nozzle body is formed of Teflon (registered trademark) resin, it may be formed of other synthetic resin or metal. Further, in the cleaning nozzle of the above-described embodiment, the nozzle body has a Laval nozzle, but the nozzle body only needs to have a divergent portion on the downstream side of the throat portion, and the convergent portion on the upstream side of the throat portion. May not be provided.

It is explanatory drawing of the washing nozzle which concerns on the 1st Embodiment of this invention. It is a graph which shows the relationship between the speed of compressed gas in the washing nozzle, and temperature. It is explanatory drawing of the washing nozzle which concerns on the 2nd Embodiment of this invention. It is a graph which shows the average particle diameter of the contaminant which can be removed with a washing nozzle.

Explanation of symbols

10: Cleaning nozzle, 11: Throat section, 12: Convergent section, 13: Divergent section, 14: Laval nozzle, 15: Compressed air, 16: Compressed gas supply section, 17: Acceleration cooling section, 18: Nozzle body, 19 : Injection port, 19a: current plate, 20: cleaning liquid, 21: cleaning liquid supply pipe, 22: discharge port, 23: inner wall surface, 24: discharge port arrangement position, 30: droplet, 31: ice particles, 32: supercooling Droplet, 33: Cleaning material, 35: Object to be cleaned, 36: Contaminant, 40: Cleaning nozzle, 41: Cleaning liquid supply pipe, 42: Compressed air, 43: Gas supply pipe

Claims (8)

A nozzle body having a divergent portion that expands in the flow direction on the downstream side of the throat portion having a circular cross section, and a cleaning liquid supply pipe that discharges the cleaning liquid in the same direction as the flow of the compressed gas supplied to the nozzle body A cleaning nozzle,
A cleaning nozzle, wherein a discharge port of the cleaning liquid supply pipe is disposed in the vicinity of the throat portion separated from an inner wall surface of the nozzle body, and the compressed gas has a sound velocity at the throat portion. The cleaning nozzle according to claim 1, wherein the nozzle body has a Laval nozzle formed as a convergent portion by reducing the diameter of the upstream side of the throat portion in the flow direction. 3. The cleaning nozzle according to claim 1, wherein a gas supply pipe for supplying another compressed gas to be mixed with the cleaning liquid is disposed in the cleaning liquid supply pipe. And cleaning nozzle. The cleaning nozzle according to any one of claims 1 to 3, wherein the discharge port of the cleaning liquid supply pipe is five times the diameter of the throat portion in the upstream direction and the downstream direction from the center of the throat portion, respectively. The cleaning nozzle is arranged within the range of the length of. The cleaning nozzle according to any one of claims 1 to 4, wherein the nozzle body has an accelerated cooling part that gradually expands in a flow direction on a downstream side of the divergent part. Cleaning nozzle to do. The cleaning nozzle according to any one of claims 1 to 5, wherein the temperature and humidity of the compressed gas are adjusted, and the temperature of the cleaning liquid is adjusted. The cleaning nozzle according to any one of claims 1 to 6, wherein a rectifying plate that aligns the flow of the compressed gas is provided upstream of the throat portion. A first step of supplying a compressed gas from an upstream side of a nozzle body provided with a divergent portion that expands in the flow direction on the downstream side of the throat portion having a circular cross section, and setting the compressed gas to a sound velocity at the throat portion;
A second step of discharging the cleaning liquid in the same direction as the flow of the compressed gas supplied to the nozzle body from the discharge port of the cleaning liquid supply pipe disposed in the vicinity of the throat portion away from the inner wall surface of the nozzle body;
The droplets generated by atomizing the cleaning liquid by the compressed gas flow in the divergent section are rapidly cooled to generate a cleaning material consisting of one or both of fine ice particles and supercooled droplets. A third step to perform,
A fourth step of injecting the supersonic cleaning material from the nozzle main body and causing the cleaning object to collide with the object to be cleaned to separate the contaminants on the object to be cleaned;
And a fifth step of sliding the cleaning material on the surface of the object to be cleaned to remove the peeled contaminants.

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