JP4206676B2 - Ozone mixing apparatus and ozone mixing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ozone mixing apparatus and an ozone mixing method for producing ozone water used for semiconductor cleaning or the like by mixing and dissolving ozone gas in ultrapure water.
[0002]
[Prior art]
Conventionally, an ejector is known as this type of gas-liquid mixing apparatus. As shown in FIG. 2, the ejector generally includes a nozzle 10, a suction chamber 11, and a diffuser 12, and jets a high-pressure liquid from the nozzle 10 to the suction chamber 11 to reduce the pressure in the suction chamber 11. Thus, the gas is sucked into the suction chamber 11 from the gas suction port 11a provided in the suction chamber 11, and the liquid and the gas are discharged from the diffuser 12 in a mixed state.
[0003]
In recent years, in the semiconductor manufacturing field, ozone water in which ozone gas is mixed and dissolved in ultrapure water has been used to clean semiconductor components. However, the ozone treatment effect such as cleaning has been improved and the processing time has been shortened. For example, the ozone concentration of ozone water is set to a high concentration of 20 ppm or more.
[0004]
In order to produce high-concentration ozone water as described above using an ejector, in order to increase the contact ratio of ozone gas, the ratio of the flow rate of ozone gas to the flow rate of ultrapure water ((ozone gas flow rate / ultra pure water flow rate) (Hereinafter referred to as “liquid / gas ratio”) and the pressure of ozone gas was increased to about 0.3 MPa in order to increase the amount of ozone gas sucked into the suction chamber.
[0005]
[Problems to be solved by the invention]
However, in the conventional ejector, when the ratio of the gas flow rate to the liquid flow rate is increased, the pressure loss in the diffuser increases, and a pressure pump is added to compensate for the pressure loss. When a pressure pump is added, when cleaning precision electronic components such as semiconductors, there is an increased possibility of particles (contaminants) entering the ultrapure water from the pump and contamination of ultrapure water with metal. There was a problem to do.
[0006]
Moreover, in order to increase the pressure of ozone gas, a pressure-resistant structure of the ozone gas generator is required, and when ozone is generated by an electrolytic method, a pinhole is generated in the electrolytic membrane and a large amount of ozone gas enters the hydrogen chamber. There was also a problem of drowning.
[0007]
Accordingly, the present invention provides an ozone mixing device and an ozone mixing method capable of dissolving ozone gas having a predetermined concentration in water even when the pressure loss is reduced, the liquid / gas ratio is increased, and the gas pressure is further reduced. Objective.
[0008]
[Means for Solving the Problems]
The object of the present invention includes a chamber having an inlet for pressurized water, a diffuser portion communicating with the chamber, and an ozone gas supply pipe inserted into the chamber and opening toward the inlet portion of the diffuser portion. The ozone gas supply pipe forms a throttle member that restricts the flow path leading to the inlet of the diffuser, the ozone gas supply pipe has a conical outer shape, and the chamber is located at the tip. This is achieved by an ozone mixing device characterized in that it has a suitable truncated cone-shaped tapered channel part, and the tip of the tapered channel part communicates with the inlet part of the diffuser part .
[0009]
It is preferable that the ozone gas supply pipe is provided so as to be able to adjust a distance between a tip end portion thereof and an inlet portion of the diffuser portion so that a throttle amount by the throttle member can be adjusted.
[0010]
It is preferable that the tapered channel portion has a taper equivalent to the tip portion of the ozone gas supply pipe.
[0011]
Preferably, water having a gauge pressure of about 0.1 to about 0.3 MPa is introduced into the inlet, and ozone gas having a gauge pressure of about 0.05 to about 0.2 MPa is supplied to the ozone gas supply pipe. .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of an ozone mixing apparatus according to the present invention will be described below with reference to the cross-sectional view shown in FIG.
[0013]
The ozone mixing device 1 includes a chamber 3 having a pressurized ultrapure water inlet 2, a diffuser part 4 communicating with the chamber 3, and an opening toward the inlet part 4 a of the diffuser part 4 inserted into the chamber 3. And an ozone gas supply pipe 5.
[0014]
The ozone gas supply pipe 5 is not intended to eject fluid at a high speed like a nozzle in a conventional ejector, but simply supplies ozone gas at a constant flow rate. Therefore, although the flow path of the ozone gas supply pipe 5 forms a nozzle that is gradually throttled in the illustrated example, it may be a through hole having the same flow path cross section without any restriction.
[0015]
The rear end portion of the ozone gas supply pipe 5 is connected to an ozone generator (not shown) and a tube (not shown), and ozone gas is sent in the direction of arrow X in the figure. Ozone gas is pressurized from an ozone generator, for example, to about 0.05 to about 0.2 MPa (gauge pressure) and sent at about 0.4 to about 40 L _N / min (L _N is liters in a standard state). It is done.
[0016]
In the illustrated example, the tip 5 a of the ozone gas supply pipe 5 has a conical outer shape, and the top is open toward the inlet 4 a of the diffuser 4. The chamber 3 has a truncated cone-shaped tapered flow path portion 3 a having a taper equivalent to that of the distal end portion 5 a, and the tapered flow path portion 3 a communicates with the inlet portion 4 a of the diffuser portion 4.
[0017]
The distal end portion 5 a of the ozone gas supply pipe 5 is inserted into the tapered flow path portion 3 a to form a throttle member that restricts the tapered flow path portion 3 a that communicates with the inlet portion 4 a of the diffuser portion 4. When the pressurized water (ultra pure water) flowing into the chamber 3 passes through the narrowed flow path, that is, the minute gap X, the flow rate is increased and the pressure is reduced, and the pressurized water is ejected to the diffuser part 4 and decelerated and pressurized in the diffuser part. Is done. It is preferable that the ultrapure water sent to the inflow port 2 is about 1 to about 100 L / min at about 0.1 to about 0.3 MPa (gauge pressure) by a water pump (not shown).
[0018]
In the illustrated example, the minute gap X formed between the tip 5a of the ozone gas supply pipe 5 and the tapered channel 3a gradually reduces the channel cross-sectional area and substantially constitutes a nozzle. ing. The minute gap X is preferably one that gradually reduces the cross-sectional area of the flow path as shown in the example in order to increase the speed of ultrapure water passing therethrough.
[0019]
The ozone gas supply pipe 5 is provided so that the distance between the tip portion 5a and the inlet portion 4a of the diffuser portion 4 can be adjusted so that the amount of restriction by the tip portion 5a, that is, the size of the minute gap X can be adjusted.
[0020]
In the illustrated example, a screw portion 5 b is formed on the outer peripheral portion of the ozone gas supply pipe 5, and this screw portion 5 b is screw-coupled to a support 6 that supports a part of the ozone gas supply pipe 5. Therefore, if the ozone gas supply pipe 5 is rotated around the axis, the tip 5a moves in the axial direction corresponding to the pitch of the screw 5b, and the size of the minute gap X can be adjusted. In the figure, reference numeral 7 denotes an O-ring.
[0021]
In the ozone mixing device 1 having the above-described configuration, ultrapure water pressurized by a pump or the like (not shown) enters the chamber 3 from the inlet 2 at a predetermined flow rate, passes through the minute gap X, and the diffuser section. 4 is injected. On the other hand, ozone gas is discharged from the ozone gas supply pipe 5 toward the inlet portion 4a of the diffuser portion 4 at a predetermined flow rate.
[0022]
The pressure of the ultrapure water that has passed through the minute gap X is reduced by the nozzle action of the minute gap. Therefore, by adjusting the minute gap X and reducing the pressure of ultrapure water near the outlet of the ozone gas supply pipe 5 to a pressure equal to or lower than the ozone gas pressure in the ozone gas supply pipe 5, the ozone gas from the ozone gas supply pipe 5 is reduced. Is likely to be discharged and mixed.
[0023]
In this way, ozone gas is entrained and mixed in the ultrapure water ejected to the diffuser section 4. The state of spraying ozone gas can be optimized by adjusting the minute gap X. That is, according to the flow rate and pressure of ultrapure water, the flow rate of ozone gas, etc., the size of the minute gap X is adjusted so as to increase the amount of atomized fine bubbles in the diffuser section 4 and the mixing of ozone gas is promoted. Let The chamber 3 constitutes a flow path of ultrapure water, but does not function as a suction chamber like a conventional ejector.
[0024]
【Example】
Example 1
Using the ozone mixing apparatus shown in FIG. 1, ozone water was produced under the following conditions.
[0025]
Diameter of diffuser throat: 2.2mmφ
Ozone gas supply pipe diameter: 1.5mm
Ozone gas concentration: 210 g / m ³ _N (m ³ _N is a standard cubic meter)
Ozone gas flow rate: 0.8 L _N / min Ozone gas pressure: 0.06 MPa
Flow rate of ultrapure water: 3L / min
Ultra pure water pressure: 0.2 MPa
Ozone concentration of ozone water: 25ppm
Ozone water pressure: 0.1 MPa
Pressure loss: 0.1 MPa
(Pressure loss = [pressure of ultrapure water]-[pressure of ozone water])
Example 2
Using the ozone mixing apparatus shown in FIG. 1, ozone water was produced under the following conditions. The second embodiment is an example in which the ozone gas flow rate is increased as compared with the first embodiment.
[0026]
Diameter of diffuser throat: 2.2mmφ
Ozone gas supply pipe diameter: 1.5mm
Ozone concentration of ozone gas: 210 g / m ³ _N
Ozone gas flow rate: 1.8 L _N / min Ozone gas pressure: 0.08 MPa
Flow rate of ultrapure water: 3L / min
Ultra pure water pressure: 0.25 MPa
Ozone concentration of ozone water: 33ppm
Ozone water pressure: 0.1 MPa
Pressure loss: 0.15 MPa
Comparative Example 1
Using the conventional ejector shown in FIG. 2, ozone gas was mixed with ultrapure water under the following conditions. The diffuser, nozzle, and suction chamber of the ejector were of the same dimensions as the corresponding parts of the ozone mixing device in FIG.
[0027]
Diffuser throat diameter: 2.2mmφ
Diameter of water injection nozzle: 1.5mm
Ozone concentration of ozone gas: 210 g / m ³ _N
Ozone gas flow rate: 1.7 L _N / min Ozone gas pressure: 0.06 MPa
Flow rate of ultrapure water: 3L / min
Ultra pure water pressure: 0.5 MPa
Ozone concentration of ozone water: 32ppm
Ozone water pressure: 0.1 MPa
Pressure loss: 0.4 MPa
Comparative Example 2
Using the same conventional ejector as Comparative Example 1, ozone water was produced under the following conditions.
[0028]
Diameter of diffuser throat: 2.2mmφ
Diameter of water injection nozzle: 1.5mm
Ozone concentration of ozone gas: 210 g / m ³ _N
Ozone gas flow rate: 0.2 L _N / min Ozone gas pressure: 0.06 MPa
Flow rate of ultrapure water: 1.5L / min
Ultra pure water pressure: 0.25 MPa
Ozone concentration of ozone water: 16ppm
Ozone water pressure: 0.1 MPa
Pressure loss: 0.15 MPa
Comparative Example 2 is an example in which the pressure of ultrapure water is reduced as compared with Comparative Example 1 (excluding the additional pressure pump).
[0029]
The flow rate of ultrapure water was 3 L / min in Comparative Example 1, but decreased to 1.5 L / min in Comparative Example 2, and the suction flow rate of ozone gas into the suction chamber was 1.7 L _N / min in Comparative Example 1. What was the minute was reduced to 0.2 L _N / min in Comparative Example 2. At this time, the ozone generation amount was reduced so as not to exceed the ozone gas pressure of 0.06 MPa.
[0030]
Referring to Example 1 and Example 2 above, it can be seen that the ozone water has an ozone concentration of 20 ppm or more and the pressure loss is 0.2 MPa or less.
[0031]
Further, in Examples 1 and 2, the pressure of ozone gas is 0.06 MPa and 0.08 MPa, and this level of pressure does not interfere with the ozone gas generator, and is special to the ozone gas generator. This is a level that does not require a withstand voltage structure.
[0032]
Moreover, increasing the flow rate of the ozone gas in Examples 1 and 2 to 0.8 L _N / min to 1.8L _N / min, the pressure loss in Example 2, was 0.15 MPa, equivalent ozone concentration Compared with the comparative example 1 obtained, it is sufficiently small, and it is in a range that does not require an additional pressurizing pump or the like in order to compensate for the pressure loss.
[0033]
On the other hand, referring to Comparative Example 1, if an attempt is made to obtain ozone water having the same ozone concentration as in Example 2, the pressure pump is increased to increase the pressure of ultrapure water to 0.5 MPa. Is required, and a pressure loss of 0.4 MPa occurs at this time.
[0034]
In Comparative Example 2, the pressure of ultrapure water is set to the same level as in the example without adding a pressure pump, and the pressure loss is reduced. However, the ozone concentration of ozone water is 16 ppm, and it is used for semiconductor cleaning. The required 20 ppm has not been reached.
[0035]
【The invention's effect】
As can be seen from the above examples, according to the ozone mixing device and the ozone mixing method according to the present invention, the pressure of ultrapure water is kept low compared to the case of producing ozone water using a conventional ejector. It is possible to produce high-concentration ozone water by eliminating the increase in pressure equipment, suppressing the ozone gas pressure to prevent the ozone generator from being damaged, and increasing the ratio of the ozone gas flow rate to the ultrapure water flow rate. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of an ozone mixing device according to the present invention.
FIG. 2 is a cross-sectional view showing a conventional ejector.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ozone mixing apparatus 2 Inlet 3 Chamber 4 Diffuser part 5 Ozone gas supply pipe

Claims (4)

An ozone mixing device for mixing ozone gas with water,
A chamber having an inlet for pressurized water;
A diffuser section communicating with the chamber;
An ozone gas supply pipe inserted into the chamber and opening toward the inlet of the diffuser part;
Forming a throttle member for restricting a flow path leading the ozone gas supply pipe to the inlet of the diffuser;
The tip of the ozone gas supply pipe has a conical outer shape,
The chamber has a frustoconical tapered channel portion adapted to the tip portion;
An ozone mixing device, wherein the tip of the tapered channel portion communicates with the inlet portion of the diffuser portion.  2. The ozone according to claim 1, wherein the ozone gas supply pipe is provided so that a distance between a front end portion thereof and an inlet portion of the diffuser portion can be adjusted so that a throttle amount by the throttle member can be adjusted. Mixing equipment. The ozone mixing device according to claim 1, wherein the tapered flow path portion has a taper equivalent to the tip portion of the ozone gas supply pipe. An ozone mixing method in which ozone is mixed with water using the ozone mixing device according to claim 1,
While allowing water with a gauge pressure of 0.1 to 0.3 MPa to flow into the inlet,
An ozone mixing method, wherein ozone gas having a gauge pressure of 0.05 to 0.2 MPa is supplied to the ozone gas supply pipe.

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