JP2005175183A - Liquid-pressurizing mechanism, and apparatus and method for controlling liquid using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid-pressurizing mechanism which can pressurize a liquid to a predetermined pressure and add minute flow volume by flow volume with high precision, wherein the gas for pressurizing the liquid will not come into contact with the liquid so that various problems occurring when the pressurizing gas is in direct contact with the liquid are solved. <P>SOLUTION: An entrance 3a connected to the supply line 32 of a chemical etc. and a holding chamber 12 are provided to one side of a cylindrical pressurizing body 2, and a pressurizing chamber 13 for pressurizing by a gas, such as compressed air is provided on the other side of the pressurizing body 2; and a partition 6 is provided so that the gas in the pressurizing chamber 13 and the liquid in the holding chamber 12 do not come into contact with each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid pressurizing mechanism, a liquid control apparatus using the same, and a liquid control method. In particular, the liquid pressurization mechanism is used in a semiconductor or liquid crystal substrate manufacturing process and the like, and is stably supplied while controlling the pressure of a liquid composed of a chemical liquid. The present invention relates to a liquid pressurizing mechanism that performs the above, a liquid control device that uses this to dilute a liquid into ultrapure water, which is another liquid, and a liquid control method.

  In recent years, for example, in a wafer cleaning process in a semiconductor manufacturing apparatus, a method change from batch cleaning to single wafer cleaning has been promoted. This is because an optimum cleaning process can be performed for each wafer to be processed. In connection with this, development of a chemical solution dilution supply device capable of in-line mixing capable of supplying diluted chemical solutions adjusted to different concentrations for each wafer is required. The present invention makes it possible to meet such demands.

When manufacturing a diluted chemical solution, it is necessary to stably supply the chemical solution (or gas) to the ultrapure water at a minute flow rate and stably, and usually a chemical solution for adding the chemical solution or gas to the ultrapure water. A feeding device is used. In the wafer cleaning process, the material constituting the chemical solution supply device is limited to PTFE or PFA, which is a fluororesin, in order to dislike the adhesion of metal ions to the wafer and the like, and further along with the operation of the chemical solution supply device. Therefore, it is required that fine dust called oils and particles is not generated.
However, the current situation is that there are no flow meters, control valves, and pumps that can cover such a very small flow rate range in the market.

  For this reason, for example, the electrical conductivity of ultrapure water after addition of acid or alkali is measured based on the electrical conductivity, and the amount of acid or alkali added is controlled / adjusted based on this measured value. (For example, refer to Patent Document 1).

In addition, there is a chemical solution supply device using a nitrogen gas pressurization tube, and there is one that enables supply of a chemical solution in an ultrafine flow rate range. This chemical solution supply device is configured to obtain a diluted chemical solution having a predetermined concentration by adding a chemical solution under pressure to pure water. Usually, a chemical solution in a pressure tube is used by using nitrogen gas as a compressed gas. Is directly pressurized.
JP 2000-208471 A

  However, the electronic material cleaning water preparation apparatus of Patent Document 1 can perform concentration control, but concentration hunting may occur when flow rate fluctuations occur in ultrapure water during actual use. . This preparation device is intended to store a diluted stock solution in a device tank for the above reason that a flow meter made of PTFE or PFE cannot be manufactured, and add this to ultrapure water as a chemical solution. Yes, high concentration stock solution cannot be added as it is. For this reason, it is necessary to install a diluting device for the high-concentration stock solution, which increases the size and price of the device.

On the other hand, there is the following problem when the chemical solution in the pressure tube is directly pressurized using compressed gas and added to pure water.
That is, since the chemical solution and the compressed gas are pressurized by direct contact, the compressed gas is dissolved in the chemical solution, and there is a possibility that bubbles such as microbubbles may be generated when the pressure is reduced at the place of use. In addition, since the atmosphere of the chemical solution may diffuse into the compressed gas source and be contaminated by this chemical solution, it is necessary to take measures against reverse diffusion such as purging from the compressed gas pressurization line. The driving cost was also extra. In particular, this compressed gas is usually nitrogen gas. However, nitrogen gas is harmful to the human body and is not desirable for use. For example, the compressed gas is expensive when compared with air.

  In addition, this chemical solution supply device has a problem in that the piping structure in the device is complicated, so that the air in the device is difficult to escape when the air in the piping is replaced with the chemical solution. When trying to do so, it may be difficult to remove the residual air inside the apparatus, so it is necessary to add a purge line.

  Furthermore, this chemical supply device generally uses a controller called a liquid level controller that controls the liquid level by measuring the liquid level position in the pipe storing the chemical liquid with a liquid level sensor. However, if this liquid level controller breaks down or malfunctions, a large amount of chemical liquid may accidentally flow out from the exhaust line side. It is necessary to devise a sequence program for valve control or to prevent the outflow of the chemical liquid to the exhaust line by making the structure of the line that makes it difficult for the chemical liquid to flow out to the discharge side. There was also.

  The present invention has been developed in view of the conventional problems, and an object of the present invention is a liquid pressurizing mechanism capable of pressurizing a liquid to a predetermined pressure and adding a minute flow rate with high accuracy. An object of the present invention is to provide a liquid pressurizing mechanism capable of solving various problems in the case where the gas for pressurizing the liquid does not contact the liquid and the gas to be pressurized contacts the liquid directly.

  In order to achieve the above object, the invention according to claim 1 is provided with an inlet / outlet connected to a supply line for a chemical solution and the like on one side of a cylindrical pressurizing body and compressed on the other side of the pressurizing body. While providing a pressurizing chamber which pressurizes with gas, such as air, the gas of a pressurizing chamber is the liquid pressurization mechanism which has arrange | positioned the partition which is non-contact with the liquid in a storage chamber.

  The invention according to claim 2 is a liquid pressurizing mechanism in which the partition wall is a bellows, and the invention according to claim 3 is that the component of the pressurizing body including the partition wall is a fluororesin such as PFA or PTFE. Or a liquid pressurizing mechanism which is another chemical resistant material.

  According to a fourth aspect of the invention, the liquid stored in the storage chamber is hydrofluoric acid, or a chemical solution such as hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, ammonia, potassium hydroxide, sodium hydroxide, or an organic acid. A liquid pressurizing mechanism.

  According to a fifth aspect of the present invention, there is provided a liquid control apparatus using the liquid pressurizing mechanism according to any one of the first to fourth aspects, wherein a process unit for adding a chemical solution to pure water step by step and diluting to a predetermined concentration; The liquid control device includes a control unit that controls the operation of the process unit.

  The invention according to claim 6 is the liquid control apparatus in which an orifice member capable of supplying the chemical solution added from the liquid pressurizing mechanism at a constant pressure is provided inside the process unit.

  The invention according to claim 7 is the liquid control device in which the orifice member has a structure in which the pressure loss is proportional to the flow rate.

  The invention according to claim 8 is a liquid control method in which a minute amount is added to another liquid that flows continuously to dilute the liquid, and the liquid is added to the other liquid by a minute flow rate at a predetermined concentration. In the process unit for diluting the liquid, a liquid pressurizing mechanism for pressurizing the liquid and adding a minute amount, a line having an orifice member in which the pressure loss of the liquid is proportional to the flow rate, and a line through which another liquid flows are provided, respectively. Is a liquid control method in which the dilution concentration is controlled to be constant by controlling the flow rate of the liquid in each line from the differential pressure between the liquid and the other liquid.

According to the first aspect of the invention, the liquid can be pressurized to a predetermined pressure and added with a minute flow rate with high accuracy, and bubbles such as microvalves can be generated in the liquid because no compressed gas is used. Absent. Moreover, cost can be suppressed. Furthermore, it is a liquid pressurizing mechanism that can be used safely and does not leave residual air in the apparatus even when the liquid is added at a very small flow rate.
Also, when trying to incorporate into other equipment, it is possible to prevent the equipment from becoming complicated and suppress the enlargement of the equipment, so that it can be incorporated in-line, for example, when incorporated into a wafer cleaning device. The space efficiency of the clean room can be increased. Furthermore, in this case, in addition to being able to easily set the concentration of the diluting solution, this concentration can be set finely, so that the liquid pressurizing mechanism can be incorporated into various cleaning apparatuses.

  According to the second and third aspects of the invention, the liquid and the gas are blocked and the liquid and the gas can be reliably prevented from coming into contact with each other. To prevent contamination.

  According to the invention which concerns on Claim 4, various chemical | medical solutions can be added and it is a liquid pressurization mechanism which can obtain various dilution chemical | medical solutions according to a use.

  According to the fifth aspect of the present invention, the liquid control device can be easily miniaturized by incorporating the liquid pressurizing mechanism, and the cost can be kept low. In addition to making it cheaper, it can be made cheaper. Also, in this case, by providing a concentration generation signal device in the cleaning device, the concentration of the diluent can be easily changed according to the signal from the concentration generation signal device. It is possible to

  According to the sixth aspect of the present invention, there is no possibility of suddenly adding a chemical solution, and the liquid control device can make a liquid such as a diluted chemical solution having a stable concentration in accordance with a change in flow rate. According to the invention which concerns, it is a liquid control apparatus which can measure correctly the differential pressure | voltage of the chemical | medical solution which flows through the inside.

According to the eighth aspect of the present invention, it is possible to finely adjust the flow rate of a liquid such as a chemical solution and the flow rate of another liquid such as pure water. Thus, it is possible to control the supply states of the liquid and the other liquid, and therefore, it is a liquid control method capable of obtaining a diluted chemical solution having a desired concentration. In addition, compared with the case of RCA cleaning, the temperature of the cleaning process can be reduced and the cost can be greatly reduced, and a high cleaning effect can be obtained.
Furthermore, it is a liquid control method capable of constantly obtaining a high-quality diluted chemical solution with high accuracy without gas being mixed into the liquid.

An embodiment of a liquid pressurizing mechanism according to the present invention will be described with reference to the drawings. In FIG. 2, reference numeral 1 denotes a liquid pressurizing mechanism main body. In the liquid pressurizing mechanism main body 1, the pressurizing main body 2 is formed by cutting a cap 3 with a PFA material and forming a cylindrical body 4 with a PFA tube. These are welded. The cylindrical body 4 may be manufactured by cutting a round bar-shaped material. Thus, the pressurizing body 2 can be made of a fluororesin such as PFA or PTFE. The pressurizing body 2 can set a discharge volume of one stroke when the pressurizing body 2 is a cylinder by adjusting the diameter, length, and the like. Reference numeral 3a denotes an inlet / outlet connected to a chemical liquid supply line 32 for a chemical liquid or the like provided on one side of the welded pressurizing body 2, and the chemical liquid can be stored in the storage chamber 12 through the inlet / outlet 3a. Further, on the other side of the pressurizing body 2, a pressurizing chamber 13 that pressurizes with a gas such as compressed air is provided, and from the bellows so that the gas in the pressurizing chamber 13 is not in contact with the liquid in the storage chamber 12. A partition wall 6 is provided. The other side is a stainless steel end flange 5 and flange lid 7, which are fixed by a bolt 15 with the flange portion 2 a of the pressurizing body 2 and the flange portion 6 a of the partition wall sandwiched between the pressurizing body 2 and the end. The flange 5 and the flange lid 7 are integrated.
In addition to the fluororesin such as PFA and PTFE, other chemical resistant materials may be used for the components of the pressurizing body 2 including the bellows 6.

  The gaskets 8 and 9 are formed of a fluororesin such as soft PTFE, and are provided with mounting holes 8a and 9a on the center side. The bellows 6 is made of a fluororesin such as PTFE, with the gasket 8 and 9 interposed between the bellows 6 and the pressurizing body 2 and between the bellows 6 and the flange lid 7 so that the fixing side of the bellows 6 is sandwiched. As described above, the bolts 15 are fixed. Since the pressurizing chamber 13 is a space inside the bellows 6, the gas in the pressurizing chamber 13 and the liquid in the storage chamber 12 are not in contact with each other. The pressurizing chamber 13 is pressurized from a gas port 7 a provided through the flange lid 7.

  Reference numeral 10 denotes a magnetic body made of a magnetic material such as iron provided on the front end side of the pressurizing chamber 13 inside the bellows 6, and 11 is a magnetic sensor capable of sensing magnetism, and the magnetic body 10 is in proximity. This makes it perceivable. The magnetic sensor 11 includes an extension-side magnetic sensor 11a and a contraction-side magnetic sensor 11b. The extension-side magnetic sensor 11a can sense the magnetic body 10 in a state where pressure is applied to the pressurizing chamber 13 and the bellows 6 is extended. On the other hand, the contraction-side magnetic sensor 11b senses the magnetic body 10 when the bellows 6 is contracted, so that the state of the pressurizing chamber 13 can be sensed. In addition, since the magnetic body 10 is provided in the pressurization chamber 13, it does not contact the liquid in the storage chamber 12, and it cannot be overemphasized that generation | occurrence | production of a metal ion can be prevented.

  The storage chamber 12 has a volume that complementarily changes in accordance with the amount of pressurization of the pressurization chamber 13, and can accommodate the amount of liquid corresponding to the pressurization amount. When the pressure chamber 13 is depressurized, the bellows 6 contracts due to the pressure of the liquid, so that the liquid is sucked into the storage chamber 12 from the entrance / exit 3a. This liquid is once filled in the storage chamber 12, and then when the pressurizing chamber 13 is pressurized, the bellows 6 expands, and the liquid is pressurized to a predetermined pressure and discharged from the inlet / outlet 3a by a predetermined amount. For a liquid having no pressure, it is also possible to pressurize the pressurizing chamber 13 with a gas after the inside of the pressurizing chamber 13 is once evacuated to introduce the liquid into the storage chamber 12.

  Moreover, since the compressed air used when pressurizing a chemical | medical solution is made into non-contact with a chemical | medical solution, it can pressurize in the state which isolate | separated the chemical | medical solution and compressed air completely, and a microbubble does not generate | occur | produce. Furthermore, there is no need for a facility for exhausting compressed air, so there is no cost, and this compressed air is less expensive than nitrogen and does not adversely affect the human body.

  In addition, when a liquid control device to be described later for adding a chemical solution to pure water is provided using the liquid pressurizing mechanism main body 1, the piping structure can be simplified and a purge line for internal residual air or the like is also provided. There is no need. In this case, since the chemical solution is once filled in the storage chamber 12, there is no need to measure the surface position of the chemical solution, and there is no possibility that the chemical solution is discharged in large quantities from the exhaust line side. Furthermore, there is no fear that the chemical vapor will reversely diffuse, and therefore the apparatus is not complicated to take these measures.

Next, a liquid control apparatus using the liquid pressurizing mechanism will be described. FIG. 1 is a schematic diagram showing a liquid control device, FIG. 4 is a schematic explanatory diagram of the liquid control device, and the liquid control device main body 20 includes a process unit 30 including a liquid pressurizing mechanism main body 1 and a control unit 50. Is done.
In the process unit 30 in FIGS. 3 and 4, the liquid pressurizing mechanism main body 1 for pressurizing the chemical solution supplied from the chemical solution supply device 25 is provided in the chemical solution supply line 32 that is a flow path for flowing the chemical solution. . In the present embodiment, two liquid pressurizing mechanism main bodies 1 are provided in parallel to the chemical liquid supply line 32, and the other side is added while the chemical liquid is being added from one of the liquid pressurizing mechanism main bodies 1. The liquid pressurizing mechanism main body 1 is replenished with liquid, and the liquid pressurizing mechanism main body 1 is always allowed to add a chemical solution by waiting in a pressurized state. Two or more liquid pressurizing mechanism bodies 1 may be provided in parallel. Further, if the liquid pressurizing mechanism body 1 is connected in series, the number of automatic valves provided in the liquid control device can be reduced. In the present embodiment, a flow meter is not used for the flow control of the liquid, but the flow rate of the chemical solution supplied using the flow meter may be feedback controlled. In this case, examples of the flow meter include an ultrasonic micro flow meter.
31a, 31b, 31c and 31d are automatic valves which are provided before and after the liquid pressurizing mechanism body 1 to open and close the chemical liquid supply line 32. The automatic valves 31a, 31b, 31c and 31d are pressurized by controlling the opening and closing thereof, respectively. A chemical solution is supplied to the mechanism body 1. 31a and 31c are automatic valves provided on the inlet side of the pressurizing mechanism bodies 1 and 1, and 31b and 31d are automatic valves provided on the outlet side.
Reference numerals 39a and 39b denote automatic valves for opening and closing a gas supply line 38 for supplying and exhausting compressed air to and from the pressurizing mechanism main body 1. The automatic valves 39a and 39b are controlled to open and close to the pressurizing mechanism main body 1. The pressure of the chemical solution added from the pressurizing mechanism body 1 can be controlled by controlling the pressurization by the compressed air. The control of the automatic valves 31a, 31b, 31c, 31d, the automatic valves 39a, 39b, other automatic valves, the gas-liquid separation pipe 33 and the like is a PLC (programmable logic controller) provided as a sequencer provided in the control unit 50. ) 51.

  The gas-liquid separation tube 33 is provided to remove bubbles that may be mixed into the chemical solution stock supplied to the chemical solution supply line 32, and the liquid level is lowered by the accumulation of bubbles in the gas-liquid separation tube 33. When the liquid level sensor 33a that senses the liquid level detects this liquid level drop, the automatic valve 34b is opened to purge the gas in the gas phase, and when the liquid level recovers to a predetermined amount of the liquid level sensor 33a, the automatic valve 34b. Close. This operation is automatically performed under the control of the sequencer 51 so that the liquid in which bubbles are mixed is not supplied to the chemical liquid supply line 32. Reference numeral 35 denotes an orifice unit. The gas discharged to the orifice unit 35 is allowed to pass therethrough to reduce the gas purge speed so that the amount of waste liquid of the gas discharged together is reduced. Reference numeral 34a denotes an automatic valve provided on the inlet side of the chemical liquid supply line 32, and the automatic supply of the chemical liquid can be stopped by opening and closing the automatic valve 34a.

The orifice member 36 shown in FIG. 5 is designed in a special structure in which the pressure loss of the chemical solution supplied from the liquid pressurizing mechanism body 1 is proportional to the flow rate, and the flow rate is proportional to the differential pressure before and after the chemical solution passes. It is possible to flow. The orifice member 36 makes it possible to change the pressure on the liquid inlet side by controlling the operating air pressure of the pressure regulating valve 37 with the electropneumatic converter (E / P) 52 of the control unit 50.
Reference numeral 36a denotes a narrow tube constituting the orifice member 36, and the flow coefficient can be changed by setting the narrow tube 36a to an appropriate inner diameter, length and number. The thin tube 36a is formed of a fluororesin such as PFA, and the distal end side of the thin tube 36a is welded and sealed as shown in the figure to close the flow path, leaving the necessary number of thin tubes 36a as a liquid flow path. it can. Reference numeral 36b denotes a sleeve for bundling the thin tubes 36a. The sleeve 36a is formed of a fluororesin such as PFA in the same manner as the thin tubes 36a. When the thin tube 36a is fixed, the sleeve 36b is welded and sealed to a length L with molten PFA (fluororesin). Yes.

  Here, there is no particular limitation on the number of thin tubes 36a that are connected in parallel, but there may be practically about 1-1000. The diameter of the narrow tube 36a may be, for example, about 10 to 1000 μm in inner diameter, and a thin tube having a hollow fiber structure is desirable.

In FIGS. 1 and 3, reference numeral 40 denotes a pure water supply line through which pure water for diluting the chemical solution flows, and the pressure automatic adjustment valve 41 is a junction 42 of the flow path with the chemical solution stock solution even when the flow rate of the pure water fluctuates. Is used to maintain a constant pressure (for example, 0.05 MPa), and the flow rate of pure water flowing through the pure water supply line 40 can be adjusted. In the present embodiment, the pressure of the pure water supply line 40 is adjusted using the automatic pressure regulating valve 41. If the pressure of pure water in the pure water supply line 40 is sufficiently stable, this pressure is adjusted. The automatic adjustment valve 41 can be omitted.
Reference numeral 43 denotes an orifice unit that reduces the speed of the diluted chemical solution after the chemical solution is added by the orifice unit 43 so that the diluted chemical solution can be supplied to the cleaning valve 45 in a stable state. The cleaning valve 45 can supply a diluted chemical solution to the outside, and this diluted chemical solution is used, for example, for cleaning a wafer. A flow meter 44 measures the flow rate of pure water whose pressure is adjusted by the automatic pressure adjustment valve 41.
In this way, the process unit 30 adds the chemical solution to the pure water at a minute flow rate and is diluted to a predetermined concentration while being controlled by the control unit 50.

Next, a liquid control method in the liquid control apparatus using the liquid pressurizing mechanism will be described.
This control method is to obtain a liquid that is a diluted chemical liquid that is diluted by adding a liquid consisting of a chemical liquid to pure water that is another liquid that continuously flows, and as a control of the liquid control device, By accurately controlling the differential pressure of the chemical solution before and after the orifice member 36, the proportion of the chemical solution to the pure water is controlled to be constant by controlling the proportion of the chemical solution injected in proportion to the flow rate of pure water. .
As the chemical solution, for example, a 50% by weight hydrofluoric acid stock solution is used, and this chemical solution is diluted with pure water, and diluted with a flow rate of 0.5 to 1.5 l / min and a concentration of 0.25 to 1.00% by weight. The acid can be produced. Other conditions for diluting hydrofluoric acid include, for example, pure water pressure of 0.10 to 0.40 MPa, hydrofluoric acid stock solution pressure of 0.10 to 0.40 MPa, and diluted hydrofluoric acid pressure of 0.05 to 0.10 MPa. desirable.
In addition, this chemical solution may be other than hydrofluoric acid. For example, a chemical solution such as hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, ammonia, potassium hydroxide, sodium hydroxide can be used. Acids can also be used as chemicals.

  As shown in FIG. 4, the liquid control device main body 20 is incorporated in a cleaning device 16 for cleaning a wafer, and can clean the wafer with a diluted chemical supplied from the liquid control device main body 20, as shown in FIG. Yes. Accordingly, the dilution concentration setting value of the chemical solution is determined by an electric signal such as 4 to 20 mA given from the cleaning device 16, and the dilution concentration can be changed according to the cleaning condition of the wafer to be cleaned.

When the cleaning valve 45 is opened in the cleaning device 16, the flow rate of the diluted chemical solution changes depending on the number of the cleaning valves 45 and the opening degree of each cleaning valve 45, and the upstream of the orifice unit 43 according to the change in the flow rate of the diluted chemical solution. The pressure on the side changes. That is, the pressure decreases as the flow rate from the cleaning valve 45 increases, and the pressure increases as the flow rate decreases.
Here, the change in the pressure of the diluted chemical liquid means that the amounts of the chemical liquid and pure water change, and the pressure on the upstream side of the orifice unit 43 corresponds to the change in the flow rate of the chemical liquid from the orifice member 36 and the pure water. Since it is related to the change in the flow rate of water, by changing the supply amount of this chemical solution and pure water according to the change in pressure of the diluted chemical solution, even if the flow rate of the diluted chemical solution changes, a predetermined concentration is obtained. Shall.
The pressure on the chemical liquid side is controlled to a predetermined pressure by the pressure adjustment valve 37, and the pressure control by the pressure control valve 37 is performed by applying a constant pressure to the operating air pressure. On the other hand, a change in the flow rate of pure water from the pure water supply line 40 is measured by the flow meter 44 and input to the sequencer 51.

In the sequencer 51, the relationship between the flow rate through the orifice member 36 and the differential pressure (the pressure of the chemical solution on the inlet side of the orifice member 36 -the pressure of pure water on the inlet side of the junction 42) is programmed in advance. Further, the sequencer 51 changes the pure water from the flow rate of pure water on the inlet side of the junction 42 and the set value of the dilution concentration of the chemical solution set in the range of 0.25 to 1.00% by weight in advance. The necessary amount of the chemical solution is programmed so as to be calculated with respect to the flow rate. First, the sequencer 51 calculates the necessary amount of the chemical solution corresponding to the changed pure water flow rate.
Next, the differential pressure of the orifice member 36 is calculated from the calculated required amount of the chemical solution. Since this differential pressure is the pressure of the chemical solution−the pressure of pure water as described above, the calculated differential pressure of the chemical solution is calculated. The required chemical pressure is obtained from the pure water pressure flowing through the automatic pressure control valve 41.
Therefore, by adjusting the signal of the electropneumatic converter 52 so that the pressure of the chemical solution becomes the same, it is possible to adjust the pressure of the pressure regulating valve 37 to adjust the amount of the chemical solution added and keep the dilution concentration constant. It becomes. The control by the electropneumatic converter 52 is performed by feedforward control in a region where the control error is large. On the other hand, when the control error is small, it is possible to realize faster control by controlling by feedback control. .

  According to this liquid control method, the upstream side pressure of the orifice member 36 can be controlled by the control unit 50 so that the flow rate of the chemical solution can immediately follow the change in the flow rate of pure water, thereby improving the accuracy of the dilution concentration. It becomes possible. In addition, even when there is some pulsation in the chemical liquid supplied from the chemical liquid supply device 25, the liquid pressure is repressurized by the liquid pressurizing mechanism body 1 in the process unit 30 to supply the chemical liquid. It is not affected by this pulsation. Moreover, since the liquid pressurization mechanism main body 1 partitions the chemical | medical solution storage part from air with the bellows 6 provided in the inside, and uses compressed air as gas for chemical | medical solution pressurization, the liquid control apparatus main body 20 is used. Various problems in using nitrogen gas can be solved.

In addition, since the liquid control device main body 20 can be an in-line type cleaning device when incorporated in the cleaning device 16, it has the following merits compared to the batch type chemical solution diluting device.
That is, since tanks such as a measuring tank, a mixing tank, and a storage tank are not necessary, the entire cleaning device can be reduced in size, thereby reducing costs. Further, since it can be incorporated into a single wafer cleaning device, it is not necessary to install an independent unit as in the case of a batch type, and further miniaturization is possible.
Furthermore, in the case of the batch type, it is difficult to change the concentration because it is necessary to discharge the liquid or the stored liquid during batch mixing, readjust the lightweight tank, etc., but in the case of an inline type cleaning device, the control unit Since the concentration can be controlled by 50, the concentration can be easily changed, and the concentration of the chemical solution can be changed in a short time even in the middle of the wafer cleaning process.
As described above, for example, when the liquid control device main body 20 is incorporated in a cassette type wafer cleaning device, the liquid cleaning solution is changed each time so as to correspond to the liquid chemical concentration for each cassette. Therefore, a single wafer cleaning apparatus capable of efficient liquid control can be provided.

  The present invention is particularly suitable for a liquid pressurizing mechanism in a liquid controller for pure water and chemicals used in semiconductor, liquid crystal substrate manufacturing processes, etc. In addition, since a liquid with an extremely small flow rate can be added, the present invention can be widely applied to processes other than semiconductor and liquid crystal substrate manufacturing processes.

It is a schematic diagram which shows a liquid control apparatus. It is a longitudinal cross-sectional view of the liquid pressurization mechanism in this invention. It is a schematic diagram which shows a process unit. It is a schematic explanatory drawing of a liquid control apparatus. It is a front view which shows an orifice member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid pressurization mechanism main body 2 Pressurization main body 3a Entrance / exit 6 Bellows (partition wall)
DESCRIPTION OF SYMBOLS 12 Storage chamber 13 Pressurization chamber 20 Liquid control apparatus main body 30 Process unit 32 Chemical solution supply line 36 Orifice member 40 Pure water supply line 50 Control unit

Claims (8)

An inlet / outlet connected to a supply line for a chemical solution or the like and a storage chamber are provided on one side of the cylindrical pressurizing body, and a pressurizing chamber for pressurizing with a gas such as compressed air is provided on the other side of the pressurizing body. The liquid pressurizing mechanism is characterized in that a partition that is in non-contact with the liquid in the storage chamber is disposed for the gas in the pressure chamber. The liquid pressurizing mechanism according to claim 1, wherein the partition is a bellows. The liquid pressurizing mechanism according to claim 1 or 2, wherein a component of the pressurizing body including the partition walls is a fluororesin such as PFA or PTFE or other chemical resistant material. The liquid stored in the storage chamber is hydrofluoric acid, or a chemical solution such as hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, ammonia, potassium hydroxide, sodium hydroxide, or an organic acid. The liquid pressurizing mechanism according to claim 1. A liquid control apparatus using the liquid pressurizing mechanism according to any one of claims 1 to 4, wherein a process unit for adding a chemical solution to pure water at a minute flow rate to dilute to a predetermined concentration and operation of the process unit are controlled. A liquid control apparatus comprising: a control unit that performs the control. The liquid control apparatus according to claim 5, wherein an orifice member capable of supplying a chemical solution added from the liquid pressurizing mechanism while maintaining a constant pressure is provided inside the process unit. The liquid control apparatus according to claim 6, wherein the orifice member has a structure in which pressure loss is proportional to a flow rate. A liquid control method for diluting a liquid by adding a small amount to another liquid that flows continuously, and adding the liquid to a liquid at a minute flow rate to dilute the liquid to a predetermined concentration. A liquid pressurizing mechanism that pressurizes liquid and adds a minute amount and a line having an orifice member in which the pressure loss of the liquid is proportional to the flow rate and a line through which another liquid flows are provided, and the differential pressure between the liquid and the other liquid A liquid control method characterized in that the dilution concentration is controlled to be constant by controlling the flow rate of the liquid in each line.

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