JP2987225B2 - Ultra-fine frozen particle manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing ultra-fine frozen particles for producing extremely fine frozen particles used for cleaning semiconductor substrates and the like.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional apparatus for producing fine frozen particles, which includes a supply source (1) for supplying a liquid to be frozen and a fine frozen particle by cooling fine droplets of the liquid to be frozen. And a spray nozzle (3) connected to the heat insulating container (2).

[0003] A heat insulating container (2) is a spray nozzle (4) for making the liquid to be frozen sent from the liquid to be frozen supply source (1) into fine droplets.
It has. Also spray nozzle (4) and spray nozzle (3)
Is connected to a high-pressure gas cylinder (5).

[0004] With the above configuration, the liquid to be frozen is sent from the supply source of the liquid to be frozen (1) to the spray nozzle (4). Then, the liquid to be frozen is finely atomized by the pressure supplied to the spray nozzle (4) and is sprayed into the heat insulating container (2). At this time, since the heat insulating container (2) is cooled by a refrigerant such as liquid nitrogen,
The atomized liquid droplets of the liquid to be frozen are frozen in the state of a mist, and become fine ice (6) having a diameter of several tens to several hundreds μm. The frozen fine-grained ice (6) is jetted from the high-pressure gas cylinder (5) to the semiconductor substrate (7) via the jet nozzle (3) into which the high-pressure gas is fed.

[0005]

Since the conventional apparatus for producing fine frozen particles is configured as described above, the particle size sprayed from the spray nozzle can be generated only at most 30 μm. Also, when the liquid to be frozen and the gas are introduced into the spray nozzle, particles of about 10 μm can be obtained, but the gas must be introduced about 1000 times the liquid to be frozen. Further, the speed of the fine droplets sprayed from the tip portion of the spray nozzle becomes close to the speed of sound, which is disadvantageous for heat exchange with the refrigerant.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to easily generate ultra-fine droplets of 10 μm or less, and to reduce the generated ultra-fine droplets at a low speed. It is an object of the present invention to obtain an apparatus for producing ultrafine frozen particles that can be introduced into an insulated container.

[0007]

An apparatus for producing ultrafine frozen particles according to the first invention of the present invention comprises spraying fine particles atomized from a two-fluid nozzle together with a dry gas into a closed container. The invention produces ultrafine frozen particles by cooling the suspended ultrafine droplets.

The apparatus for producing ultrafine frozen particles according to the second invention supplies a liquid to be frozen onto a rotating disk at a high speed, and uses the centrifugal force of the rotating disk to produce ultrafine particles at the end of the disk. Ultrafine frozen particles are produced by generating droplets and cooling the ultrafine droplets.

Further, the apparatus for manufacturing ultra-fine frozen particles according to the third invention supplies the liquid to be atomized to the atomizing section vibrated by the ultrasonic vibration and applies ultrasonic vibration to the liquid to be frozen to thereby form the liquid to be frozen. The frozen liquid is made ultrafine, and the ultrafine droplets are cooled to produce ultrafine frozen particles.

[0010]

According to the first aspect of the present invention, ultrafine droplets are generated and floated by spraying fine particles atomized from a two-fluid nozzle into a closed container. As a result, an ultrafine and uniform particle size is taken out at a low speed and introduced into an insulated container.

In the second aspect of the invention, the liquid to be frozen supplied on the disk rotating at a high speed is made ultra-fine at the end of the disk, and the ultra-fine liquid droplet is produced at a low speed. It is taken out, introduced into an insulated container, and cooled.

Further, in the third invention, since the liquid to be frozen is made ultra-fine by the ultrasonic vibration, the ultra-fine liquid droplet is sprayed by diffusion after being ultra-fine on the vibration surface. . Therefore, the spray speed is very low.

[0013]

FIG. 1 shows an embodiment of the first invention, in which (11) is a closed container, (12) is a two-fluid nozzle, and (13) is a two-fluid nozzle (12). Introduce the frozen liquid tank,
(14) is a frozen liquid introduction pipe, (15) is a dry gas introduction pipe, (16)
Is an ultra-fine droplet introduction tube heater, (17) is an ultra-fine droplet introduction tube for introducing ultra-fine droplets from the closed container (11) to the heat insulating container (18),
(19) is an ultrafine frozen particle, (3) is an injection nozzle, (7) is an object to be injected, and (20) is a drainage nozzle.

The above-mentioned two-fluid nozzle (12) is composed of a dry gas ejected at a supersonic speed from one direction, for example, pressurized air containing droplets atomized by a shearing action on the way, while the other is at the same pressure. This nozzle has a function of repeating the mutual shearing by colliding with the air flow at a certain angle and generating ultrasonic waves to further atomize the droplets.

Next, the operation will be described. The liquid to be frozen introduced from the tank to be frozen (13) through the liquid to be frozen introduction pipe (14) is mixed with the dry gas introduced from the dry gas introduction pipe (15), and then mixed with the two-fluid nozzle (12). Spray the liquid to be frozen into (11). At that time, the amount of the liquid to be frozen is adjusted by the valve for adjusting the amount of liquid to be frozen (21).

Of the fine droplets introduced into the closed container (11), the ultra-fine droplets float in the closed container (11) because of their light weight. At this time, the diameter of the droplet sprayed from the two-fluid nozzle (12) is 1 to 20 μm depending on the combination of the dry gas pressure, the dry gas flow rate and the amount of the liquid to be frozen, the viscosity, and the surface tension.
Adjust to the extent.

Further, the amount of the ultrafine droplets can be increased by increasing the number of the two-fluid nozzle (12) in the closed vessel (11).

The uniform ultrafine droplets generated as described above are introduced into the heat insulating container (18) through the ultrafine droplet introduction pipe (17) by the dry gas injected from the two-fluid nozzle (12). Is done. Here, by introducing a high-pressure gas into the closed vessel (11), the ultrafine droplets can be introduced into the heat-insulated vessel (18). When high-pressure gas is supplied to the injection nozzle (3), the inside of the heat insulating container (18) becomes negative pressure due to the ejector effect. Utilizing this negative pressure, ultrafine droplets can be introduced into the heat insulating container (18). The ultrafine droplets introduced from the ultrafine droplet introduction pipe (17) are cooled and frozen by the refrigerant supplied in the heat insulating container (18), and ultrafine frozen particles (19) are generated.

After passing through the heat insulating container (18), the ultrafine frozen particles (19) are sucked by the injection nozzle (3) and injected toward the object (7) such as a substrate. On the other hand, when the ultrafine droplet is introduced into the heat insulating container (18), the ultrafine droplet may freeze in the ultrafine droplet introduction pipe (17). This is prevented by the ultrafine droplet introduction tube heater (16). In addition, droplets attached to the inner wall surface in the closed container (11) are drained from the drain nozzle (20).

FIG. 2 shows an embodiment of the second invention, in which a horizontal disk (22) rotating in a closed container (11) and a motor (23) for rotating this disk are provided. Have been. In addition, the same reference numerals as those in FIG. 1 denote the same parts, and a description thereof will be omitted.

Next, the operation will be described. Closed container (11)
The disk (22) attached to the is rotated by a motor (23) at a speed of several tens to tens of thousands of rpm. The liquid to be frozen is introduced into the rotating disk (22) from above the liquid to be frozen tank (13). At this time, the amount of the liquid to be frozen introduced into the disk (22) is adjusted by the valve for adjusting the amount of liquid to be frozen (21). Thus, the rotating disk (2
When the liquid is supplied to 2), the liquid jumps out at the end of the disc by centrifugal force, and is further cut off by air resistance, and fills the closed container (11) as ultra-fine droplets. At this time, to control the droplet diameter, the rotation speed of the disk (22), the disk diameter, the disk structure, the amount of the liquid to be frozen, the viscosity and surface tension of the liquid to be frozen, and the air inside the closed container (11) It is necessary to appropriately combine the viscosity and density, but by performing the optimal combination, 1-10 μm
Ultra-fine droplets of a uniform degree are obtained.

The uniform ultrafine droplets generated as described above are introduced into the heat insulating container (18) from the ultrafine droplet introduction pipe (17) by the high-pressure gas introduced into the closed container (11). In addition, when high-pressure gas is supplied to the injection nozzle (3), the inside of the heat insulating container (18) becomes negative pressure due to the ejector action, and ultra-fine droplets are introduced into the heat insulating container (18) using this negative pressure. You can also. Here, the high-pressure gas introduced into the closed vessel (11) is
Such as N ₂ gas or the compressed air.

The ultra-fine droplets introduced from the ultra-fine droplet introduction pipe (17) are cooled and frozen by the refrigerant supplied into the heat insulating container (18) to become ultra-fine frozen particles (19). After the ultra-fine frozen particles (19) pass through the heat insulating container (18), the injection nozzle
It is sucked by (3) and injected toward the object (7).

FIG. 3 shows an embodiment of the third invention, in which (24) is an ultrasonic vibration device for generating ultrasonic vibration by piezoelectric ceramic, and (25) is an ultrasonic vibration device (24). This is an atomizing section for concentrating the vibration, and the liquid to be frozen from the liquid to be frozen tank (13) is supplied to this portion. (26) is a curling prevention gas introduction hole. The same reference numerals as those in FIG. 1 denote the same parts, and a description thereof will be omitted.

Next, the operation will be described. Insulated container (18)
The ultrasonic vibration device (24) mounted on the upper part vibrates by the piezoelectric ceramic, and this vibration is transmitted to the atomizing unit (25). Here, when the liquid to be frozen is supplied to the atomizing section (25) from the liquid to be frozen supply tank (13), the liquid to be frozen becomes ultrafine by vibration, and a uniform mist of 10 to several tens μm is generated. This fog
Since it is obtained by vibration, it sinks or diffuses slowly by the force of gravity or the like. The droplet diameter changes depending on the vibration frequency, the viscosity of the liquid to be frozen, the flow rate, and the like. The ultrafine droplets generated in this way are cooled and frozen by the refrigerant supplied in the heat insulating container (18), and become ultrafine frozen particles (19),
It is sucked by the injection nozzle (3) and injected to the object (7).

Further, since the refrigerant is supplied into the heat insulating container (18), the air flow in the heat insulating container (18) is turbulent. Droplets adhere to the top plate of the heat insulating container (18), the ultrasonic vibrator (24), etc.
May freeze. Therefore, a high-pressure gas is introduced from the outer peripheral portion of the ultrasonic vibration device (24) from the introducing portion (26), so that the ultra-fine droplets are not wound up by the air flow.

[0027]

As described above, according to the first aspect of the present invention, the liquid to be frozen is sprayed and floated in the closed vessel by the two-fluid nozzle, so that the droplet diameter can be made ultra-fine. It can be generated uniformly. Further, since the droplets are ultrafine and uniform, the heat exchange rate with the refrigerant is extremely high. In addition, since the heat can be introduced into the heat insulating container in the low pressure state, the heat exchange time is increased, and thus there is an effect that the running cost can be reduced and the device can be reduced in size. Further, according to the second aspect of the present invention, since the generation of the droplets is made by the rotating disk, the diameter of the droplets is made ultra-fine and a uniform one can be obtained. In addition, the droplet is under no pressure (atmospheric pressure)
Since the droplets can be generated in a state, the speed at which the droplets pass through the heat insulating container can be extremely reduced. Therefore, the heat exchange time with the refrigerant increases, the device becomes smaller,
In addition, since the droplet diameter is small and uniform, the droplet can be frozen even if the temperature difference with the refrigerant is small, and there is an effect that the running cost can be reduced. Further, according to the third aspect, the generation of the droplets is performed by ultrasonic vibration, so that the spray speed is reduced, and the heat exchange time between the droplets and the refrigerant is increased. Since the freezing can be performed even if the temperature difference is small, there is an effect that the running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an elevational sectional view showing an embodiment of the first invention of the present invention.

FIG. 2 is an elevational sectional view of one embodiment of the second invention.

FIG. 3 is an elevational sectional view of an embodiment of the third invention.

FIG. 4 is a vertical sectional view of a conventional apparatus for producing fine frozen particles.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Closed container 12 Two-fluid nozzle 13 Freezing liquid tank 15 Dry gas introduction pipe 17 Ultrafine droplet introduction pipe 18 Insulated vessel 19 Ultrafine frozen particles 22 Disk 24 Ultrasonic vibration device 25 Atomization part

Continuation of the front page (56) References JP-A-4-110577 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/304

Claims (3)

(57) [Claims] 1. A closed container, a two-fluid nozzle for spraying a liquid to be frozen together with a dry gas into the closed container, and an ultrafine droplet of the liquid to be frozen floating generated in the closed container is introduced by a refrigerant. An apparatus for producing ultrafine frozen particles, comprising: a heat insulating container that generates ultrafine frozen particles. 2. An airtight container, a disk provided in the airtight container and rotated at a high speed, and ultrafine droplets of a liquid to be frozen which are dropped and atomized and float on the disk are introduced into the airtight container and cooled by a refrigerant. An apparatus for producing ultrafine frozen particles, comprising: a heat insulating container that generates fine frozen particles. 3. An insulated container, an atomizing part installed in the heat insulating container, into which a liquid to be frozen is introduced, and an ultrasonic vibrating device for driving the atomizing part, wherein an ultrafine liquid is generated by ultrasonic vibration. An apparatus for producing ultrafine frozen particles, wherein the liquid to be frozen as droplets is cooled by a refrigerant to produce ultrafine frozen particles.