JPH11102226A - Device for controlling pure water temperature with mixing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the temperature of pure water without contaminating it and to attain use in a corrosive atmosphere. SOLUTION: This device controls the temperature of pure water by mixing warm pure water and ordinary pure water through a three-way valve. In this case, the three-way valve is composed of an air operate valve (AV) 2 for adjusting the mixing ratio of warm pure water and ordinary pure water by operating while receiving the operation of air pressure. The AV 2 is provided with a casing 31, valve element 32 movably installed on the casing 31, and diaphragm 33 for driving the valve element 32 with air pressure. The casing 31 and valve element 32 are composed of resins, and the diaphragm 33 is composed of a rubber and arranged in no contact with pure water. Therefore, since the AV 2 is not a motor-driven type, the use in the corrosive atmosphere is allowed and no metal ion or particle is not included in pure water through the AV 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the temperature of pure water used for cleaning a wafer in a semiconductor manufacturing process, and more particularly, to controlling the temperature of pure water by mixing. To a control device.

[0002]

2. Description of the Related Art Conventionally, in the semiconductor manufacturing process, if particles (particles) such as dust adhere to a wafer, it becomes an obstacle in processing a circuit including a fine element such as a transistor. Therefore, the wafer and the like are cleaned with the cleaning water containing no particles.

On the other hand, since the acid used in wet etching performed after photographic exposure as a part of semiconductor circuit processing is a strong acid such as hydrofluoric acid, it is not preferable that the acid remains on the wafer. Therefore, after the etching, the wafer must be cleaned. These cleaning waters are required not only to contain no particles but also to contain no impurities such as metal ions. If such impurities adhere to the wafer even in a very small amount, the impurities have a great effect on the electrical characteristics and deteriorate the yield of semiconductor products.

In such a case, extremely high-purity water called pure water is used as the washing water. The semiconductor manufacturing equipment is provided with a dedicated pure water producing apparatus, and sends pure water to a cleaning apparatus and a wet etching apparatus. In this type of pure water production apparatus, contamination of impurities in the piping should be avoided.

Meanwhile, there is a need for temperature control of pure water used in semiconductor manufacturing equipment, and it may be necessary to control pure water to a predetermined temperature. Here, as a method of controlling the temperature of the cleaning water, mixing room temperature water and hot water,
There is a method of controlling the temperature of the washing water to a predetermined temperature by changing the ratio between the two. Generally, in a water heater or the like, mixing of hot water and normal temperature water is performed using a three-way valve having a built-in ball valve. This type of three-way valve may be of a motor-driven type.

[0006]

However, there are some problems when trying to control the temperature of pure water used in a semiconductor manufacturing process by using the above-mentioned conventional apparatus. That is, usually, since the pipe joint of the three-way valve is made of metal,
The metal ions may elute and contaminate the pure water. Alternatively, when the three-way valve is a motor-driven ball valve, particles are generated at the sliding portion of the ball,
Similarly, pure water may be contaminated.

On the other hand, in a motor-driven three-way valve, metal is used for a mechanism such as a gear. In particular, in a semiconductor manufacturing process, there is a problem that such a three-way valve may be placed in a corrosive atmosphere due to an acid, and a three-way valve including a metal mechanism cannot be used.

The present invention has been made in view of the above circumstances, and has as its object to control the temperature without contaminating pure water and make it possible to use the device in a corrosive atmosphere. An object of the present invention is to provide a device for controlling the temperature of pure water by mixing.

[0009]

In order to achieve the above object, an invention according to claim 1 controls the temperature of pure water by mixing hot pure water and normal temperature pure water by a three-way valve. In the pure water temperature control device, the three-way valve is configured by an air operated valve configured to adjust the mixing ratio between hot pure water and normal-temperature pure water by operating under the action of air pressure, and The operating valve includes a casing, a valve body movably provided in the casing, and a diaphragm for driving the valve body by air pressure, the casing and the valve body are made of resin, and the diaphragm is made of rubber. And being disposed in a non-contact manner with pure water.

According to the above configuration, the temperature of the pure water is controlled by mixing the hot pure water and the normal temperature pure water in the three-way valve. Here, since the three-way valve is formed of an air operated valve that operates by the action of air pressure and is not a motor-driven type including a metal mechanism such as a gear, use in a corrosive atmosphere due to acid is permitted. Furthermore, since the casing and valve body of the air operated valve are made of resin, and the diaphragm is made of rubber and arranged in non-contact with pure water, metal ions and particles enter pure water passing through the air operated valve. Nothing.

According to a second aspect of the present invention, in order to achieve the above object, in the configuration of the first aspect, the invention is electrically driven to proportionally adjust the air pressure acting on the air operated valve. An electropneumatic regulator, a temperature detecting means for detecting the temperature of the pure water mixed by the air operated valve, and an opening of the air operated valve so that the detected pure water temperature becomes a predetermined set temperature. The control means for controlling the electropneumatic regulator is provided as much as possible.

According to the above construction, in addition to the operation of the first aspect of the invention, the temperature of the pure water mixed by the air operated valve is detected by the temperature detecting means, and based on the detected temperature, the control means controls the electropneumatic operation. Control the regulator. That is, in order to determine the opening of the air operated valve so that the detected pure water temperature becomes a predetermined set temperature, the control means performs feedback control of the electropneumatic regulator, whereby the pure water temperature converges to the set temperature. Will be adjusted to

According to a third aspect of the present invention, in order to achieve the above object, the temperature detecting means comprises a platinum resistor coated with a resin. .

According to the above construction, in addition to the function of the second aspect of the present invention, the means for detecting the temperature of the mixed pure water is a platinum resistor coated with a resin (for example, "fluororesin"). Since it is configured, metal ions do not flow out into pure water.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a control device for controlling the temperature of pure water by mixing according to the present invention.

In this embodiment, a pure water temperature control device of the present invention is applied to a cleaning apparatus used for cleaning a wafer in a semiconductor manufacturing process.

FIG. 1 shows a conceptual configuration of a pure water temperature control device 1. The controller 1 controls the temperature of pure water by mixing hot pure water and normal-temperature pure water by an air operated valve (hereinafter, referred to as [AV]) 2 as a three-way valve. . This control device 1 has A
In addition to V2, an electropneumatic regulator 3, a platinum resistor 4 as temperature detecting means, and a temperature controller 5 as control means are provided.

The AV2 is operated under the action of air pressure to adjust the mixing ratio between hot pure water and normal-temperature pure water. The AV2 has a first introduction port 6 for introducing hot pure water, a second introduction port 7 for introducing normal-temperature pure water, and an outlet port 8 for introducing mixed pure water. The AV 2 further has a driving unit 9 driven by air pressure. The first introduction port 6 is supplied with hot pure water controlled by the AV 10 having a two-way valve. The temperature of the hot pure water is, for example, about “80 to 90 ° C.”. Normal-temperature pure water controlled by another AV 11 composed of a two-way valve is introduced into the second introduction port 7. The temperature of the ordinary temperature pure water is, for example, “2
0 to 25 ° C ”.

The electropneumatic regulator 3 has a drive unit 9 for the AV2.
Are electrically driven in order to proportionally adjust the air pressure acting on the air, that is, the operating pressure. FIG. 2 shows an air circuit configuration and an electric circuit configuration of the electropneumatic regulator 3. The regulator 3 includes an air supply proportional valve 21 for air supply, an exhaust proportional valve 22 for exhaust, a pressure sensor 23, and a PID circuit 24. Each of the proportional valves 21 and 22 is composed of an electromagnetic valve. An input port of the air supply proportional valve 21 is connected to a supply source (not shown) of an operation pressure for operating the AV2. Exhaust proportional valve 22
Are connected to an exhaust pipe (not shown).
The output port of the air supply proportional valve 21 and the input port of the exhaust proportional valve 22 are connected to the drive unit 9 of the AV 2 and the input port of the pressure sensor 23, respectively. The PID circuit 24 is connected to the temperature controller 5. The PID circuit 24 has AV2
A command signal of the temperature controller 5 is input in order to adjust the operation pressure on the drive unit 9 to a predetermined target value. Then, the PID circuit 24 adjusts the operating pressure acting on the drive unit 9 of the AV 2 to the target value by adjusting each proportional valve 2.
1 and 22 are controlled. At this time, the PID circuit 24 monitors the detection value of the pressure sensor 23 and controls the two proportional valves 21 and 22 so that the detection value becomes the target value. This PID
The circuit 24 executes the above control based on the command signal from the temperature controller 5 and controls each of the proportional valves 21 and 22 to adjust the opening of the AV2. For this purpose, the PID circuit 24 stores a predetermined control program in its memory.

The platinum resistor 4 is coated with a fluorine resin. The platinum resistor 4 is for detecting the temperature of the pure water mixed in the AV 2, and a part thereof is disposed in the pure water at the outlet port 8 of the AV 2. The temperature controller 5 is for controlling the electropneumatic regulator 3 to determine the opening of the AV 2 so that the pure water temperature detected by the platinum resistor 4 becomes a predetermined set temperature. An arbitrary set temperature is input to the controller 5 by a user. This controller 5
The detection value of the platinum resistor 4 is monitored, and the feedback control of the electropneumatic regulator 3 is executed so that the detection value becomes the set temperature. For this purpose, the controller 5 stores a predetermined control program in its memory in advance.

FIG. 3 is a sectional view showing the structure of AV2.
The AV 2 includes a casing 31, a valve 32 provided reciprocally inside the casing 31, and the driving unit 9 described above. The drive unit 9 includes a diaphragm 33 for driving the valve body 32 by air pressure. Casing 31
Has the above-described first and second introduction ports 6 and 7 and an outlet port 8. The casing 31 further has a valve hole 34 that allows the ports 6 to 8 to communicate with each other. The lead-out port 8 is provided with the platinum resistor 4 described above.

On the upper and lower sides of the valve hole 34, valve chambers 35 and 36 are provided.
Are respectively provided. The valve body 32 provided in the valve hole 34 has a rod 37 and upper and lower valve portions 38 and 39 provided at both upper and lower ends thereof. Each valve part 38, 39
Are arranged in the corresponding valve chambers 35 and 36, respectively. Each valve section 38, 39 partitions the corresponding valve chamber 35, 36 up and down.

In FIG. 3, the upper side of the upper valve section 38 constitutes the driving section 9 described above. In FIG.
A diaphragm receiver 40 is provided at the upper end of the diaphragm 33, and the above-described diaphragm 33 is fixed on the diaphragm receiver 40. The diaphragm 33 divides the inside of the drive unit 9 into an upper pressurizing chamber 41 and a lower atmospheric chamber 42. An operating pressure adjusted by the electropneumatic regulator 3 is introduced into the pressurizing chamber 41 through a pressurizing port 43.
Atmosphere is introduced into the atmosphere chamber 42 through an atmosphere port 44.

In FIG. 3, the lower side defined by the lower valve portion 39 constitutes a spring chamber 45. In the figure, a spring guide 46 is provided at the lower end of the lower valve portion 39, and a spring 47 disposed in a spring chamber 45 is engaged with the guide 46. This spring 47
Urges the valve body 32 upward in the drawing. Spring room 45
Is introduced through the atmosphere port 48.

In the upper valve chamber 35, the opening of the valve hole 34 forms an upper valve seat 49 corresponding to the upper valve section 38. In the lower valve chamber 36, the opening of the valve hole 34 is
The lower valve seat 51 corresponding to No. 9 is formed. Therefore, as shown in FIG. 3, when the valve body 32 moves upward, the lower valve portion 39
Comes into contact with the lower valve seat 51, and the upper valve portion 38 is separated from the upper valve seat 51. Conversely, when the valve element 32 moves downward, the upper valve portion 38 abuts on the upper valve seat 49 and the lower valve portion 39 moves to the lower valve seat 51.
Move away from Such an operation changes the opening degree of AV2. In this embodiment, the valve element 32 and the valve hole 34 basically correspond to each valve portion 3 corresponding to each valve seat 49, 51.
Only the rods 8 and 39 abut each other, and the rod 37 and the valve hole 34 do not slide with each other. in this way,
In the AV2, the contact portion between the members inside the AV2 is as small as possible.

In FIG. 3, the casing 31 is made of polypropylene as a resin, and has two valve portions 38, 39.
Is made of fluororesin. The diaphragm 33 is made of rubber and is arranged in non-contact with pure water.

Next, the operation of the pure water temperature controller 1 configured as described above will be described. According to the above configuration, the temperature of the pure water is controlled by mixing the hot pure water and the normal-temperature pure water by the three-way valve. Here, since the three-way valve is constituted by AV2 which operates by the action of air pressure and is not a motor-driven type including a metal mechanism such as a gear, use of the AV2 in a corrosive atmosphere due to acid is permitted. You. Therefore, AV2 can be used even in a corrosive atmosphere.

In this embodiment, the casing 31 and the valve body 32 of the AV 2 are made of resin. In particular, the casing 31 is made of polypropylene, and both valve portions 38 and 39 of the valve body 32 are made of fluororesin. Further, a diaphragm 33 for operating the valve body 32 is made of rubber, and is arranged in non-contact with pure water. Therefore, AV2
No metal ions or particles enter into pure water passing through. As a result, the temperature can be controlled without contaminating the pure water.

In addition, in this embodiment, the temperature of the pure water mixed by the AV 2 is detected by the platinum resistor 4, and the electropneumatic regulator 3 is controlled by the temperature controller 5 based on the detected temperature. That is, the temperature of the pure water mixed by the AV 2 is detected by the platinum resistor 4. The detected pure water temperature is monitored for the temperature controller 5 to control the electropneumatic regulator 3. That is, the temperature controller 5 performs feedback control of the electropneumatic regulator 3 so as to determine the opening of the AV 2 so that the detected pure water temperature becomes a predetermined set temperature. Here, the electropneumatic regulator 3 controls the magnitude of the operating pressure introduced into the pressurizing chamber 41 of the drive unit 9 of the AV 1. As a result, the valve element 32 moves up and down, and the upper valve seat 49 and the upper valve portion 38
And the ratio between the flow path area between the lower valve seat 51 and the flow path area between the lower valve portion 39 changes. As a result, the mixing ratio of warm pure water and normal-temperature pure water introduced into AV2 is changed. Thus, the temperature of the mixed pure water is adjusted so as to converge to the set temperature. As a result,
The temperature of pure water can be precisely and promptly controlled to the set temperature. That is, high accuracy and high responsiveness can be realized in controlling the pure water temperature.

In addition, in this embodiment, a platinum resistor 4 coated with a fluorine resin is used for temperature detection indispensable for feedback control of the pure water temperature. Therefore, even if a part of the platinum resistor 4 is arranged in the pure water mixed by the AV 2, the platinum resistor 4 does not directly contact the pure water, and the platinum resistor 4 enters the pure water from the platinum resistor 4. No metal ions flow out. In this sense, the pure water temperature can be feedback-controlled without contaminating the pure water.

It should be noted that the present invention is not limited to the above-described embodiment, and may be carried out by appropriately changing the configuration without departing from the spirit of the invention.

For example, in the above-described embodiment, the temperature of the hot pure water and the normal-temperature pure water used for mixing is set to “8”.
0 to 90 ° C ”and“ 20 to 25 ° C ”, but other temperatures may be used.

[0033]

According to the first aspect of the present invention,
The three-way valve is constituted by an air operated valve, the casing and the valve body of the air operated valve are constituted by resin, and the diaphragm is also constituted by rubber to be arranged in non-contact with pure water. Therefore, since the air operated valve is not of a motor driven type, it can be used in a corrosive atmosphere due to an acid, and metal ions and particles do not enter pure water passing through the air operated valve. Therefore, the temperature can be controlled without contaminating the pure water, and the water can be used even in a corrosive atmosphere.

According to the second aspect of the present invention, in the first aspect of the present invention, an electropneumatic regulator for adjusting the air pressure to the air operated valve and a temperature detection for detecting the temperature of the mixed pure water. Means and control means for controlling the electropneumatic regulator to determine the opening of the air operated valve so that the detected pure water temperature becomes the set temperature. Therefore, in addition to the functions and effects of the first aspect, the pure water temperature is adjusted so as to converge to the set temperature.
For this reason, there is an effect that high accuracy and high responsiveness can be realized in controlling the pure water temperature.

According to a third aspect of the present invention, in the second aspect of the present invention, the temperature detecting means is formed of a platinum resistor coated with a resin. Therefore, in addition to the function and effect of the invention of claim 2, there is no outflow of metal ions from the platinum resistor to pure water.
The effect is that the temperature can be controlled without contaminating the pure water.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram showing a pure water temperature control device according to an embodiment.

FIG. 2 is a circuit diagram showing an air circuit and an electric circuit of the electropneumatic regulator.

FIG. 3 is a sectional view showing the structure of an air operated valve (AV).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control device of pure water temperature 2 Air operated valve (AV) 3 Electropneumatic regulator 4 Platinum resistor (constituting temperature detecting means) 5 Temperature controller (constituting controlling means) 31 Casing 32 Valve element 33 Diaphragm

Claims (3)

[Claims] 1. A pure water temperature control device wherein the temperature of pure water is controlled by mixing hot pure water and normal temperature pure water by a three-way valve, wherein the three-way valve is operated by the action of air pressure. Thereby, it is constituted by an air operated valve adapted to adjust a mixing ratio of the hot pure water and the normal temperature pure water, and the air operated valve is provided in a casing and a valve body movably provided in the casing. And a diaphragm for driving the valve body by the pneumatic pressure; and the casing and the valve body are made of resin, and the diaphragm is made of rubber and is arranged in non-contact with the pure water. And a controller for controlling the temperature of pure water by mixing. 2. The pure water temperature control device according to claim 1, wherein an electropneumatic regulator electrically driven to proportionally adjust the air pressure acting on the air operated valve; and the air operated. Temperature detecting means for detecting the temperature of the pure water mixed by the valve, and the electro-pneumatic regulator to determine the opening degree of the air operated valve so that the detected pure water temperature becomes a predetermined set temperature. A control device for controlling the temperature of pure water by mixing, comprising: control means for controlling. 3. The pure water temperature control device according to claim 2, wherein said temperature detecting means comprises a platinum resistor coated with a resin.