KR20070078699A - Liquid chemical supply system - Google Patents

Abstract

A chemical supply system is provided to detect securely the flow of gas into a pump chamber of a chemical pump and to perform properly a chemical spraying process of the chemical pump. A chemical supply system includes a chemical pump, an operating unit, an operating amount detecting unit, a displacement manipulating unit and a determination unit. The chemical pump(10) includes a pump chamber for filling chemicals and a volume variable member(12) capable of varying the volume of the pump chamber. The chemical pump is capable of absorbing or spraying the chemicals on the basis of the variation of volume of the pump chamber. The operating unit is used for operating the volume variable member. The operating amount detecting unit is used for detecting an operating amount of the volume variable member. The displacement manipulating unit is used for changing the position of the volume variable member in a closed state of a chemical port. The determination unit is used for determining the existence of gas in the pump chamber on the basis of the results of the operating amount detecting unit.

Description

Chemical liquid supply system {LIQUID CHEMICAL SUPPLY SYSTEM}

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the outline of the chemical liquid supply system of embodiment of this invention.

2 is a view showing an outline of the discharge flow rate of the controller.

3 is a diagram showing pump discharge characteristics.

4 is a diagram illustrating a state of piston displacement when gas is mixed.

5 is a diagram showing a relationship between the piston displacement amount and the air volume in the cylinder.

6 is a timing chart for explaining the suction / discharge operation by the chemical liquid pump and the air mixing determination.

7 shows a schematic configuration of a system having two chemical liquid pumps.

8 is a timing chart for explaining the chemical liquid discharge operation.

FIG. 9 is a diagram for explaining an outline of air mixing determination in the second embodiment. FIG.

It is a figure which shows the relationship between the fluctuation amount of bellows length, and the air volume in a pump chamber.

This invention claims the priority based on Japanese Patent Application No. 2006-018504 for which it applied on January 27, 2006, and all the content of the application is integrated by reference in this specification.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a chemical liquid supply system for sucking and ejecting chemical liquids using a chemical liquid pump, and is very suitable for use in chemical liquid use processes of semiconductor manufacturing apparatuses, such as chemical liquid application processes. A chemical liquid supply system.

In the chemical liquid use step of the semiconductor manufacturing apparatus, a chemical liquid pump is used to apply the chemical liquid to the semiconductor wafer by a predetermined amount. As the chemical liquid pump, the pump chamber filled with the chemical liquid and the pressure working chamber into which the compressed air is introduced are divided into partition members such as bellows or diaphram, and the partition is made by variably adjusting the air pressure in the pressure working chamber. The position of the member may be changed and suction and discharge of the chemical liquid may be performed.

In the system using the chemical liquid pump as described above, a chemical liquid supply pipe through a chemical liquid tank or the like is provided, and the chemical liquid is sequentially supplied to the chemical liquid pump through the chemical liquid supply pipe. Therefore, the chemical liquid is sucked into the pump chamber of the chemical liquid pump in accordance with the change of the position of the partition member, and then discharged into the chemical liquid discharge piping.

In the above system, for example, when the residual amount of the chemical liquid in the chemical liquid tank serving as the chemical liquid supply is reduced, air (gas) is mixed with the chemical liquid flowing through the chemical liquid supply pipe, and the air flows into the pump chamber of the chemical liquid pump. In this case, the operation of replenishing the chemical liquid to the chemical liquid tank is performed, and the air removal operation in the pump chamber is executed. In connection with this, a technique has been proposed in which a liquid level detection sensor is provided in a chemical liquid tank, and a notification of the reduction of the residual chemical liquid in accordance with the liquid level level detected by the liquid level detection sensor has been proposed (for example, Japanese Patent Laid-Open No. 2000-A). See 223393).

In the case where air is mixed in the pump chamber of the chemical liquid pump, such as when the chemical liquid in the chemical liquid tank disappears, for example, suction and discharge of the chemical liquid pump are repeatedly performed to remove the air in the pump chamber. However, if it is not confirmed whether the air removal has been completely performed, there is a concern that the chemical liquid cannot be discharged as desired when the chemical liquid pump is used with air remaining in the pump chamber. In particular, in the case where the quantitative discharge of the chemical liquid is to be performed, a disadvantage may occur in that the accuracy of the discharge amount is lowered. In addition to the case where the chemical liquid in the chemical liquid tank disappears, it is also assumed that air is mixed in the pump chamber, and a technique for determining the presence or absence of air mixing in the pump chamber is preferable.

It is a main object of the present invention to provide a chemical liquid supply system which can reliably detect gas incorporation in a pump chamber of a chemical liquid pump, and furthermore, can discharge the chemical liquid by a chemical liquid pump very suitably.

A 1st chemical liquid supply system which is one aspect of this invention includes the following. That is, a chemical liquid pump having a pump chamber for filling the chemical liquid, a volume variable member for changing the volume of the pump chamber, and sucking or discharging the chemical liquid based on the volume change in the pump chamber by the volume variable member, and the volume variable member. Actuation means for actuating the member, and actuation amount detecting means for detecting an actuation amount of the variable volume member.

Therefore, the displacement operation means which performs a displacement operation so as to change the position of a volume variable member by the said operation means in the state which closed the chemical liquid entrance and exit to the pump chamber, and the operation | movement by the said operation amount detection means in the said displacement operation. And determining means for determining the presence or absence of gas in the pump chamber based on the amount detection progress.

According to the first chemical liquid supplying system, the displacement operation is executed so as to change the position of the variable volume member by the operation means in a state where the chemical liquid entrance to the pump chamber is closed, that is, the pump chamber is closed. The presence or absence of gas in the pump chamber is determined based on the result of the operation amount detection by the amount detecting means.

In short, the chemical is an incompressible fluid, while the gas is a compressible fluid. Therefore, if only the chemical liquid exists in the pump chamber, the volume in the pump chamber does not change even if the displacement operation of the volume variable member is performed in the pump chamber closed state (the volume variable member does not operate). On the other hand, if gas is mixed in the pump chamber, when displacement operation of the volume variable member is performed in the pump chamber closed state, the volume in the pump chamber changes by the compressed or expanded portion of the gas (the volume variable member operates). Therefore, it is possible to determine the presence or absence of gas in the pump chamber based on the operation amount detection result by the operation amount detection means. As a result, mixing of gas in the pump chamber of the chemical liquid pump can be reliably detected, and furthermore, it is possible to perform discharge supply of the chemical liquid by the chemical liquid pump very suitably.

For example, when the gas discharge operation (air removal operation or the like) is performed after gas mixing in the pump chamber, it is also possible to reliably determine whether the gas has been completely discharged.

The 2nd chemical liquid supply system which is another aspect of this invention contains the following. That is, it has a pump chamber for filling a chemical liquid, a volume variable member capable of changing the volume of the pump chamber, and a biasing means for biasing the volume variable member in a predetermined direction, and the volume against the biasing force of the biasing means. An operation to operate the variable member and to detect or operate the chemical liquid pump for sucking or discharging based on the change in volume of the pump chamber, the operation means for operating the variable volume member, and the operation amount of the variable volume member Quantity detection means.

Therefore, in the state where the chemical liquid suction port leading to the pump chamber is opened, the displacement operation of the variable volume member by the operating means is performed against the force of the biasing means, after which the pump chamber is sealed and at the same time the operating means Displacement operation means for releasing the displacement operation of the variable volume member by means of, and after displacement operation of the variable volume member is released by the displacement operation means, the gas in the pump chamber based on the operation amount detection result by the operation amount detection means. And determining means for determining the presence or absence of a.

According to the second chemical liquid supply system, in a state where the chemical liquid suction port leading into the pump chamber is opened, displacement operation of the variable volume member by the operating means is performed against the force of the biasing means, and then the pump chamber is sealed and Displacement operation of the variable volume member by the operating means is released. At this time, under the release state of the displacement operation of the volume-variable member, the force to which the biasing means tries to return to an original state acts. Therefore, after the displacement operation cancellation of the volume variable member, the presence or absence of the gas in a pump chamber is determined based on the operation amount detection result by an operation amount detection means.

The chemical liquid pump may have a pressure working chamber which is divided in the pump chamber by the variable volume member, and the volume variable member may be operated by adjusting the gas pressure in the pressure working chamber by the operating means. .

In this case, it is preferable that the displacement operation means performs the displacement operation of the variable volume member by adjusting the gas pressure in the pressure working chamber by the operation means.

In this configuration, the pressure of the gas supplied to the pressure working chamber is adjusted by the operating means to perform the displacement operation of the volume variable member, so that the volume variable member operates in conjunction with the displacement operation. Therefore, when performing displacement operation of the volume variable member like the said 1st or 2nd chemical liquid supply system, adjustment of the gas pressure in a pressure working chamber is performed by an operation means.

Further, at the time of sucking or discharging the chemical liquid by the chemical liquid pump, a target operation amount of the variable volume member is set, and the actual operation amount required by the detection result by the operation amount detection means is determined to the target operation amount. It is also preferable to include feedback control means for feedback control of the operating state of the actuation means to coincide.

In this case, at the time of suction or discharge of the chemical liquid by the chemical liquid pump, the operation amount feedback control is performed so that the target operation amount of the volume variable member and the actual operation amount coincide. Here, since the operation amount of the variable-volume member and the volume change in the pump chamber generally have a correlation, by performing the operation amount feedback control as described above, the volume change in the pump chamber can be substantially controlled as desired. As a result, the suction flow rate or the discharge flow rate of the chemical liquid can be controlled very precisely at a desired flow rate.

In this case, the operation amount detection means is an essential component in performing the operation amount feedback control. In that case, if it is set as the structure which determines the presence or absence of gas in a pump chamber using the detection result of an operation amount detection means, a new sensor etc. for performing determination of a gas presence are not needed. Therefore, it can be said that it is preferable in order to simplify structure.

As another very suitable configuration, when determining the presence or absence of gas in the pump chamber, the gas amount (air volume) in the pump chamber may be estimated based on the operation amount detection result by the operating amount detecting means.

When gas is mixed in the pump chamber of the chemical liquid pump, the operating amount of the variable volume member changes according to the amount of gas, and the larger the amount of gas, the larger the operating amount of the variable volume member. At this time, it can be considered that there is a correlation between the amount of gas and the operation amount of the volume variable member. Therefore, according to this configuration, it is possible to appropriately request the amount of gas in the pump chamber.

The chemical liquid stored in the storage container (chemical liquid tank or the like) may be supplied to the chemical liquid pump through the chemical liquid pipe.

In this case, at the time of determining the presence or absence of gas in the pump chamber, it is preferable to determine that the chemical liquid stored in the storage container has become a predetermined amount or less based on the operation amount detection result by the operation amount detection means.

When the chemical liquid stored in the storage container decreases, gas (air) flows into the pump chamber of the chemical liquid pump along with the chemical liquid pipe. In such a case, if the presence or absence of gas in the pump chamber can be reliably determined as described above, it can be easily determined that the chemical liquid in the storage container is below a predetermined amount (including the chemical liquid zero state).

At this time, when the gas amount (estimated value) in the pump chamber becomes more than the prescribed amount, it is good to determine that the chemical liquid in the storage container is less than or equal to the predetermined amount. Alternatively, when the gas amount (estimated value) has gradually increased in the suction or discharge process of the chemical liquid repeatedly executed, it may be determined that the chemical liquid in the storage container has become a predetermined value or less.

By the way, the chemical | medical solution supply system can also include only one inside of the said pump chamber, and can also contain several.

Therefore, when the single pump chamber is included, suction and discharge of the chemical liquid are alternately repeatedly performed in the pump chamber, and when the pump chamber is included, the plurality of pump chambers are used in a predetermined order for suction. It is also good to perform the operation and the discharge operation.

In these cases, the determination means is the presence or absence of gas in the pump chamber until after the completion of the suction of the chemical liquid in each pump chamber, or until the next chemical liquid suction is performed after the completion of the discharge. It is desirable to determine.

In these configurations, the presence or absence of gas in the pump chamber can be reliably determined during the suction and discharge strokes of the chemical liquid by the chemical liquid pump. As a result, even if gas enters the pump chamber at an unexpected timing, it can be timely determined.

Further, in the case of the chemical liquid pump in which the suction and discharge of the chemical liquid are alternately repeated by the same pump chamber, in the system using a single chemical liquid pump, the chemical liquid is discharged intermittently. At this time, the suction operation and the discharge operation are performed by using the plurality of pump chambers in a predetermined order, whereby the discharge of the chemical liquid can be performed continuously without interruption.

Therefore, it is more preferable that the volume change operation in the pump chamber by the volume varying member be performed first at the time of chemical liquid suction than at the time of chemical liquid discharge.

According to this structure, the volume change operation | movement of the pump chamber by a volume variable member is performed first at the time of chemical liquid suction. Therefore, it is possible to determine the presence or absence of the gas in the pump chamber by using the remaining time after the chemical liquid suction (the remaining time until the next chemical liquid suction). At this time, the volume change rate in the pump chamber is correlated with the flow rate of the chemical liquid at the time of chemical liquid suction or discharge, and the chemical liquid flow rate at the time of chemical liquid suction improves to a relatively rough degree, whereas the chemical liquid flow rate at the time of chemical liquid discharge is high. To be controlled to a degree. At this time, the structure which performed the volume change operation | movement in the pump chamber at the time of chemical liquid suction as above before the chemical liquid discharge is the reverse structure (the structure which performed the volume change operation in the pump chamber at the time of chemical liquid discharge before the chemical liquid suction). Compared with)), it can be said that it is a structure suitable for controlling the chemical liquid flow rate at the time of chemical liquid discharge to a high degree.

As another suitable structure, when it is determined by the said determination means that gas enters into the said pump chamber, you may be provided with a means for notifying this.

According to this structure, when it is determined that gas enters in a pump chamber, since this is notified, an operator can know early that gas was mixed in a pump chamber. Therefore, for example, when the chemical liquid from the chemical liquid supply source (in the chemical liquid tank) is lost, it is possible to quickly replenish the chemical liquid.

The above and other objects, features and advantages of the present invention will become apparent from the following specification when taken in conjunction with the accompanying drawings which illustrate, by way of example, preferred embodiments of the invention.

(1st embodiment)

EMBODIMENT OF THE INVENTION Hereinafter, 1st Embodiment which actualized this invention is described according to drawing. This embodiment is specific about the chemical liquid supply system used in manufacturing lines, such as a semiconductor device, and the basic structure of the said system is demonstrated based on FIG.

The chemical liquid supply system of FIG. 1 includes a chemical liquid pump 10 for sucking and discharging the chemical liquid. In the chemical liquid pump 10, a bellows-type partition member 12 serving as a variable volume member is accommodated in the pump housing 11, and the bellows-type partition member 12 is used to pressure the pump chamber 13 and the pressure. The working chamber 14 is partitioned. The bellows-type partition member 12 has a bellows 15 of elastic material in the axial direction, and a partition plate 16 provided at one end (lower portion of the drawing) of the bellows 15, The other end (upper part of the figure) of the bellows 15 is fixed to the annular fixing plate 17. The partition plate 16 moves by expansion and contraction of the bellows 15, and the volume of the pump chamber 13 and the pressure action chamber 14 changes, respectively. In this case, since the total volume of the pump chamber 13 and the pressure working chamber 14 is unchanged regardless of the expansion and contraction of the bellows 15, the volume increase amount of the pump chamber 13, for example, This is equivalent to volume reduction (of course, the reverse is also the case).

In the pump housing 11, a suction port 18 and a discharge port 19 communicating with the pump chamber 13 are formed, a suction pipe 1 is connected to the suction port 18, and the discharge port 19 is provided. The discharge pipe 11 is connected to this. The suction pipe 21 is provided with a suction valve 23 which is a suction side on / off valve, and the suction valve 23 is opened and closed in accordance with an energized state of the solenoid valve 24. The discharge pipe 22 is provided with a discharge valve 25 which is a discharge side on / off valve, and the discharge valve 25 is opened and closed in accordance with the energization state of the solenoid valve 26. For example, the suction valve 23 and the discharge valve 25 are constituted by an air operated valve that is opened and closed by air pressure, and is applied to the energized state of the solenoid valves 24 and 26. Accordingly, the air pressure acting on each of the valves 23 and 25 is adjusted, and the valves 23 and 25 are opened and closed accordingly.

The suction pipe 21 constitutes a chemical liquid supply passage for supplying the chemical liquid to the pump chamber 13, and the chemical liquid stored in the chemical liquid tank (chemical liquid storage container) (not shown), or the chemical liquid supplied from the chemical liquid pipe of the factory. It is supplied to the pump chamber 13 through this suction pipe 21. As a result, the chemical liquid is filled into the pump chamber 13. In addition, the discharge pipe 22 constitutes a chemical liquid discharge passage for discharging the chemical liquid filled in the pump chamber 13, and the chemical liquid discharged from the pump chamber 13 is discharged through the discharge pipe 22. Is supplied. The chemical liquid ejecting nozzle is disposed so as to drop the chemical liquid at the center position of the semiconductor wafer placed on the rotating plate or the like while being directed downward, and an appropriate amount of the chemical liquid is transferred from the chemical liquid ejecting nozzle onto the semiconductor wafer. By dripping, the application | coating operation | movement of the chemical liquid to the wafer surface is performed.

Similarly, a distribution port 27 communicating with the pressure action chamber 14 is formed in the pump housing 11, and an electrical regulator 28 is connected to the distribution port 27. The electric regulator 28 constitutes an air pressure adjusting means for adjusting the air pressure in the pressure acting chamber 14, and compressed air is supplied to the pressure acting chamber 14 by a switching operation of a built-in electronic switching valve. The compressed air supply state to supply and the atmospheric open state which discharges the compressed air in the same pressure acting chamber 14 to the outside are switched.

A case main body 31 is assembled in the pump housing 11, and an elongated circumferential rod that protrudes toward the case main body 31 is formed in the through hole 32 formed in the pump housing 11. , 33) is slidably inserted. In other words, one end of the rod 33 protrudes in the pressure chamber 14, and the other end of the rod 33 protrudes from the inner space surrounded by the case main body 31. The partition plate 16 of the bellows-type partition member 12 is coupled to an end portion of the pressure working chamber 14 side of the rod 33, and the partition plate 16 is moved (that is, the telescopic movement of the bellows 15). With this, the rod 33 reciprocates in the up-down direction of the figure.

Moreover, the spring bearing plate 34 is connected to the edge part at the side of the case main body 31 of the rod 33, and the compression coil spring is between this spring bearing plate 34 and the outer wall surface of the pump housing 11. (35) is intervened. The rod 33 is always biased upward in the drawing by the biasing force of the compression coil spring 35. The compression coil spring 35 corresponds to a biasing means for biasing the bellows-type partition member 12 in a direction opposite to the air pressure in the pressure action chamber 14.

With the above configuration, in the state where the compressed air is not introduced into the pressure action chamber 14 (atmospheric open state), the bellows 15 of the bellows-type partition member 12 is forced by the force of the compression coil spring 35. It becomes a contracted state and the volume in the pump chamber 13 increases. At this time, the chemical liquid is sucked into the pump chamber 13 via the suction pipe 21 by opening the suction valve 23 and closing the discharge valve 25. In the compressed air supply state, compressed air supplied from a pneumatic source (not shown) is introduced into the pressure operating chamber 14 through the electrostatic regulator 28 and the distribution port 27, and the pressure operating chamber According to the balance between the air pressure in 14 and the force of the compression coil spring 35, the bellows 15 is elongated and the volume in the pump chamber 13 is reduced. At this time, by closing the suction valve 23 and opening the discharge valve 25, the chemical liquid filled in the case main body 31 is discharged through the discharge pipe 22.

In the case main body 31, a position detector 36 for detecting the amount of movement of the rod 33 (that is, the amount of expansion and contraction of the bellows 15) is provided. In Fig. 1, reference numeral 37 denotes a linear bearing for holding the rod 33 reciprocally, and reference numeral 38 denotes a shaft seal for preventing air leakage in the pressure acting chamber 14. to be.

The controller 40 is a tank control device mainly comprising a microcomputer composed of a CPU, various memories, and the like, and controls the state of suction and discharge of the chemical liquid by the chemical liquid pump 10. The controller 40 receives a suction / discharge signal, a suction speed command, and a discharge flow rate command from a management computer (not shown) which manages the entire system, and a position detection signal is input from the position detector 36. . Therefore, the controller 40 controls the opening / closing state of the suction valve 23 and the discharge valve 25 as the state of energizing or non-energizing the solenoid valves 24 and 26 based on the signal input each time, The control command value (air pressure command value) is calculated with respect to the regulator 28, and the state of the electropneumatic regulator 28 by the said command value is controlled. At this time, in particular, the controller 40 controls the electro-pneumatic regulator so that the moving speed of the partition plate 16 (rod 33) accompanying the expansion and contraction of the bellows 15 at the time of suction and discharge of the chemical liquid becomes the target moving speed. Feedback control of the state of (28). In addition, the controller 40 calculates the discharge flow rate value based on the position detection signal of the position detector 36, and outputs the calculated value to a management computer or the like.

Next, the outline | summary of discharge flow volume control in the controller 40 is demonstrated using FIG.

The controller 40 calculates the moving speed of the partition plate 16 at the time of suction of the chemical liquid based on the suction speed command, and calculates the moving speed of the partition plate 16 at the time of discharging the chemical liquid based on the discharge flow rate command. do. Here, at the time of calculating the moving speed at the time of chemical liquid discharge, the moving speed is calculated based on the pump discharge characteristic indicating the relationship between the moving speed and the discharge flow rate. Specifically, the movement amount of the partition plate 16 and the discharge of the chemical liquid pump 10 have a relationship shown in FIG. 3. According to FIG. 3, the pump discharge amount is linear with respect to the movement amount of the partition plate 16, and the moving speed of the partition plate 16 is calculated using this relationship.

Here, if the discharge flow rate is Q, the bellows effective area is A, the moving distance of the partition plate 16 is X, and the moving time of the partition plate 16 is t, and the pump discharge characteristic is formulated, the characteristic is

Q = A * X / t

Appears as In the above formula, "X / t" corresponds to the moving speed of the partition plate 16, and the moving speed can be calculated by the above formula.

In addition, the controller 40 selects either the movement speed at the time of suction or the movement speed at the time of discharge based on the suction / discharge signal. At this time, the selected moving speed corresponds to the target moving speed of the partition plate 16. Therefore, the air pressure command value is calculated on the basis of the deviation between the target moving speed of the partition plate 16 and the actual moving speed (actual moving speed) of the partition plate 16, and the electro-pneumatic regulator is based on the air pressure command value. The driving of 18 is controlled.

On the other hand, the controller 40 calculates the actual moving speed (actual moving speed) of the partition plate 16 based on the detection result of the position detector 36 designed for the chemical liquid pump 10. The calculated value of the actual moving speed is used not only for the feedback control of the electric regulator 28 but also for the calculation of the discharge flow rate each time. Regarding the discharge flow rate calculation, the controller 40 converts the actual moving speed of the partition plate 16 into the discharge flow rate using the aforementioned pump discharge characteristics (e.g., the relationship in FIG. 3), and converts the result into the discharge flow rate. The calculated value is output to a management computer or the like.

By the way, in the chemical | medical solution supply system of the said structure, when gas mixes with the chemical liquid which flows through the suction pipe 21, the gas will flow in into the pump chamber 13 of the chemical liquid pump 10. FIG. In such a case, when gas is mixed in the pump chamber 13, an error occurs in the discharge amount of the chemical liquid and there is a fear that the degree of discharge amount control is lowered. In addition, gas is mixed in the pump chamber 13 as described above when the chemical liquid in the chemical liquid tank as the chemical liquid supply source decreases or when the chemical liquid disappears. Thus, in the present embodiment, a method of determining that gas has been mixed into the pump chamber 13 of the chemical liquid pump 10 based on the air pressure by the electric regulator 28 and the detection result of the position detector 36 is described. Suggest.

In short, the gas is compressible while the chemical liquid is an incompressible fluid. Therefore, in the state where the pump chamber 13 is filled with chemical liquid and the entrance and exit of the same pump chamber 13 are closed together (the suction valve 23 and the discharge valve 25 are closed together), the electric regulator 28 is carried out. The bellows 15 is not stretched even if the air pressure caused by it is increased or decreased, so that the bellows stretch amount (bellows length) detected by the position detector 36 is unchanged. On the other hand, when gas enters into the pump chamber 13, similarly, in the state in which the entrance and exit of the pump chamber 13 were closed together (the suction valve 23 and the discharge valve 25 were closed together), the electric regulator ( When the air pressure by 28) increases or decreases, the bellows 15 expands and contracts accordingly, and it is detected by the position detector 36.

The basic principle is explained with reference to FIG. 4, (a) shows the case where the cylinder S which is a closed space becomes "liquid: gas = 1: 0" by volume ratio, and (b) shows the liquid / gas = inside the cylinder S by volume ratio. (C) shows the case where the inside of the cylinder S is "liquid: gas = 1: 1" by volume ratio, respectively. Therefore, the displacement amount (DELTA) X of the piston P at the time of applying the force F1 of the downward direction of the figure to the piston P is shown.

In the case of FIG. 4A, only the liquid in the cylinder S is contained, and even if the force F1 is applied to the piston P, the position of the piston P does not change (ΔX = 0). In contrast, in the case of (b) and (c), the piston P is applied by the displacement amount ΔX corresponding to the expansion of the gas in the cylinder S, with the application of the force F1 to the piston P. This position changes. In this case, the presence or absence of the gas in the cylinder S can be determined by whether the position of the piston P changes.

Here, the displacement amount ΔX of the piston P corresponds to the gas amount (air volume) in the cylinder S, and generally, the relationship shown in FIG. 5 is established. According to FIG. 5, when displacement amount (DELTA) X is known, the gas amount (air volume) in cylinder S can be known. The relationship in FIG. 5 is required based on the gas state equation (PV = nRT).

In the system configuration of FIG. 1, determination of air mixing in accordance with suction and discharge of the chemical liquid is performed as shown in FIG. 6. In FIG. 6, (a) shows the change of the air pressure (that is, the pressure change in the pressure chamber 14) by the electro-pneumatic regulator 28, and (b), (c) shows the chemical liquid pump 10 in FIG. The state of bellows shrinkage, (d) shows the open / close state of the suction valve 23, and (e) shows the open / close state of the discharge valve 25, respectively. In addition, in (b) and (c), (b) shows the case where air mixing in the pump chamber 13 does not generate | occur | produces, and (c) shows the case where air mixing has occurred. In this example, in the controller 40, air is mixed between the suction stroke (t1 to t2 in FIG. 6) and the discharge stroke (t3 to t4 in FIG. 6) by the chemical liquid pump 10. FIG. The determination is made to be executed.

In Fig. 6, first, at the timing t1, the suction valve 23 is opened and the discharge valve 25 is closed, and the air regulator 28 gradually decreases the air pressure in this state. In connection with this, the bellows 15 shrink | contracts, and the chemical liquid is sucked in the pump chamber 13 via the suction pipe 21. As shown in FIG. Therefore, the suction valve 23 is closed at the timing t2.

At timing t2, the chemical liquid suction in the pump chamber 13 is completed, and the same pump chamber 13 is brought into a sealed state. In this state, the air pressure by the electro-pneumatic regulator 28 is subsequently reduced. In this case, the air pressure is gradually changed toward the reduced pressure at the timing t2. At this time, if air is not mixed in the pump chamber 13, as shown in FIG. 6B, the bellows 15 does not contract. On the other hand, if air is mixed in the pump chamber 13, as shown in FIG. 6C, the bellows 15 shrinks in accordance with the air pressure change (A in FIG. 6). The shrinkage of this bellows 15 is detected by the position detector 36, so that air mixing can be determined. When it is determined that air mixing has occurred, a notification signal for notifying air mixing is output from the controller 40 to a warning device or the like.

At this time, in particular, the controller 40 estimates the degree of air mixing (that is, the air volume in the pump chamber 13) based on the detection result of the position detector 36. Therefore, a warning is issued when the estimated air volume is more than a predetermined level. In addition, the controller 40 compares the estimated air volume with a predetermined liquid reduction determination value, and when the air volume reaches the liquid reduction determination value, determines that the chemical liquid from the chemical liquid supply source (chemical liquid tank) is gone. Also good. In addition, a warning or a liquid reduction judgment is made when an air mixing occurrence is repeatedly determined a predetermined time by an air mixing determination performed at each chemical liquid suction, or when the air volume tends to increase (the air volume has gradually increased). May be performed.

Therefore, after that, at the timing t3, the discharge valve 25 is opened, and the air pressure gradually increases by the electrostatic regulator 28 in that state. In connection with this, the bellows 15 extends, and the chemical liquid in the pump chamber 13 is discharged from the discharge pipe 22 side. Thereafter, the discharge valve 25 is closed at timing t4. Hereinafter, the same operation as the above timings t1 to t4 is repeatedly performed.

In the actual chemical liquid supply system, a plurality of chemical liquid pumps 10 are provided, and the continuous chemical liquid supply operation can be realized by alternately repeating the ejection operation and the supply operation. 7 shows a schematic configuration of a system having two chemical liquid pumps 10a and 10b. The two chemical liquid pumps 10a and 10b shown in FIG. 7 all have the same configuration as the chemical liquid pump 10 described with reference to FIG. Omit the description. The suction pipes 21 of the chemical liquid pumps 10a and 10b are in contact with a common suction port (chemical liquid tank or chemical liquid pipe of a factory), and the discharge pipe 22 is connected to a common discharge port (chemical liquid discharge nozzle). In contact.

In Fig. 7, the bellows 15 is in a contracted state, and in this state, the bellows 15 is stretched thereafter, so that the discharge of the chemical liquid filled in the pump chamber 13 is caused. Is done. In the chemical liquid pump 10b on the right side, the bellows 15 is in an extended state, and in such a state, the bellows 15 contracts thereafter, whereby the chemical liquid suction to the pump chamber 13 is performed.

The controller 40 controls the opening and closing states of the suction valve 23 and the discharge valve 25 on the basis of the input signals as described above, using the two chemical liquid pumps 10a and 10b as the control target. The control command value (air pressure command value) for each electric regulator 28 is calculated, and the state of the electric regulator 28 is controlled by the said command value. Moreover, the controller 40 has the above-mentioned air mixing determination function, and performs air mixing determination for every pump according to the detection result of the position detector 36 provided in each chemical liquid pump 10a, 10b.

8 is a time chart for explaining the chemical liquid discharge operation of the chemical liquid supply system. In Fig. 8, the two chemical liquid pumps 10a and 10b alternately repeat the suction operation and the discharge operation to realize continuous chemical liquid supply to the semiconductor wafer. In the description of FIG. 8, for convenience, one chemical liquid pump 10 is the pump A and the other chemical liquid pump 10 is the pump B, and the suction valve and the discharge valve are also referred to as (A) and (B). ) To distinguish.

Now, before timing a, the pump A is in the state of the chemical liquid pump 10a of FIG. 7, the pump B is in the state of the chemical liquid pump 10b of FIG. 7, and both the suction valve and the discharge valve are It is closed. Therefore, the chemical liquid suction and discharge in the pump are performed at or below timing a with the generation of the start signal.

That is, on the pump A side, after the discharge valve A is opened at timing a, the bellows 15 expands with the air pressure rise by the electro-regulator 28, and chemical liquid discharge is performed. (Timing (b-g)). In addition, in parallel with the chemical liquid discharge from the pump A, on the pump B side, the suction valve B is opened at the timings c to d to suck the chemical liquid.

Therefore, in the pump B, after the suction of the chemical liquid is completed, the temporary pressure reduction process of the air pressure by the electro-regulator 28 is performed (timing (d-e)), and the pump movement with respect to the decompression of the air pressure is performed. Therefore, the presence or absence of air mixing is determined. At this time, when the bellows expansion and contraction occurs according to the decompression of the air pressure, it is detected by the position detector 36, and it is determined that there is air mixing in the pump chamber 13.

Thereafter, the discharge valve B is opened at the timing f. At timing g, the bellows 15 expands with the air pressure rise by the electro-pneumatic regulator 28 on the pump B side, and chemical liquid discharge is performed (timing g-i). At the timing h at which the suction of the chemical liquid is completed in the pump A, the temporary pressure reduction process of the air pressure by the electro-pneumatic regulator 28 is performed. Therefore, as described above, the presence or absence of air mixing is determined in accordance with the pump movement according to the decompression of the air pressure.

Thereafter, suction / discharge operations are alternately performed at the pumps A and B, and the chemical liquid is continuously discharged from the tip of the chemical liquid discharge nozzle. According to the series of steps described above, the discharge period TA of the chemical liquid by the pump A and the chemical liquid discharge period TB by the pump B are set continuously, and the chemical liquid is continuously discharged without being interrupted. In addition, since the discharge speed of the chemical liquid is controlled to be constant, the respective discharge periods TA and TB become the same, and stable supply of the chemical liquid can be performed.

Here, when the suction speed and discharge speed of the chemical liquids of the pumps A and B are compared, the suction speed is larger. That is, the time required for the chemical liquid suction in the pump chamber 13 is shorter than the time required for the discharge of the chemical liquid. By the way, when the suction / discharge operation of the chemical liquid is repeated, the chemical liquid suction is ended quickly and air mixing determination in the pump chamber 13 is made using the remaining time after the chemical liquid suction (the remaining time until the next chemical liquid suction). It is possible. This makes it possible to equalize the discharge periods TA and TB of the pumps A and B while performing air mixing determination in the middle of the suction / discharge operation of the chemical liquid as described above.

In addition, the chemical liquid flow rate at the time of chemical liquid aspiration should be relatively rough, whereas the chemical liquid flow rate at the time of chemical liquid discharge is required to be controlled to a high degree. At this time, the structure which enlarged the suction speed of a chemical liquid as mentioned above controls the chemical liquid flow rate at the time of chemical liquid discharge to a high degree compared with the structure (structure which the discharge rate of chemical liquid was larger) on the contrary. It is a very suitable configuration.

According to the present embodiment described above, the following excellent effects can be obtained.

In the chemical liquid pump 10, the inside of the pump chamber 13 is sealed to change the air pressure by the electric regulator 28, and air mixing is determined based on the bellows extension amount (change in the bellows length) at that time. In the case where air is mixed in the pump chamber 13, the air mixing can be reliably detected. According to the detection result of air mixing, it can also be determined that the chemical liquid disappeared from the chemical liquid tank. At this time, when the air removal operation is performed after the air mixing, it is also possible to surely determine whether the gas is completely discharged. By the way, it becomes possible to perform the discharge supply of the chemical liquid by the chemical liquid pump 10 suitably.

At the time of suction or discharge of the chemical liquid, the pump chamber (for the operation amount feedback control) was configured to feedback control the moving speed of the partition plate 16 constituting the bellows-type partition member 12. The volume change of 13 can be controlled as desired. This makes it possible to control the suction flow rate or the discharge flow rate of the chemical liquid to a high degree with a predetermined flow rate.

In this case, the position detector 36 is an indispensable component for controlling the operation amount feedback. Under the present circumstances, in the said structure which determines the air mixing in the pump chamber 13 using the detection result of the position detector 36, a new sensor etc. are not necessary in order to perform air mixing determination. By the way, it can be said that it is preferable in order to simplify structure. For example, although there exists a conventional technique which uses the liquid level detection sensor etc. which detect the liquid level level in a chemical liquid tank, and determines the liquid reduction from the detection result of the said sensor, in the structure of this embodiment, a liquid level detection sensor is used. Not required, the configuration can be simplified.

The chemical liquid pump 10 aspirates or discharges the chemical liquid using the air pressure adjusted by the electro-pneumatic regulator 28 as a driving source. For this reason, unlike the electric system which performs the flow control by an electric motor, there is no possibility of the damage by heat, and even the chemical liquid which requires temperature management can be used suitably. Moreover, compared with the structure of an electric actuator, it is also possible to simplify the structure of a pump drive system.

By using two chemical liquid pumps 10, the respective pumps 10 are alternately suctioned and discharged, so that it is possible to carry out continuously without reducing the discharge of the chemicals. Moreover, since it is set as the structure which feedback-controls the moving speed of the bellows type partition member 12 (partition plate 16) as mentioned above, since it is also possible to make the time required for chemical liquid discharge from each pump constant every time, Stable supply of chemicals is possible.

In the case where continuous discharge is performed by the chemical liquid pump 10, air mixing is determined after the suction of the chemical liquid is completed and until the next chemical liquid discharge is performed. Therefore, the air in the pump chamber 13 is unprecedented at the timing. Even if mixed, it can be timely determined.

In the chemical liquid pump 10, in order to allow the suction speed of the chemical liquid to be larger than the discharge speed, and to mix the air using the remaining time after the chemical liquid suction (the remaining time until the next chemical liquid suction), a good chemical liquid discharge degree is determined. It is possible to appropriately perform the air mixing determination while holding.

In the chemical liquid pump 10, the chemical liquid suction speed is made larger than the discharge speed, and air mixing determination is made using the remaining time after the chemical liquid suction speed (the remaining time until the next chemical liquid suction), thereby maintaining a good chemical liquid discharge degree. In doing so, it becomes possible to appropriately perform the air mixing determination.

(2nd embodiment)

In the above embodiment, in the chemical liquid pump 10, the air pressure is changed by the electro-pneumatic regulator 28 with the inside of the pump chamber 13 being closed, and air mixing is determined based on the bellows expansion and contraction at this time. In the second embodiment, the above method relating to the air mixing determination is changed. That is, in the present embodiment, first, the suction valve 23 is opened to allow suction, and then the air pressure of the electro-pneumatic regulator 28 is controlled, and the bellows type is applied against the force of the compression coil spring 35. The position of the partition member 12 is changed. Next, the pump chamber 13 is made into the sealed state, and the air pressure control state of the electric regulator 28 is canceled in that state. Therefore, air mixing is determined based on the change of the bellows length at that time.

In this embodiment, the outline | summary of air mixing determination is demonstrated more concretely using FIG. In addition, the case where air mixing in the pump chamber 13 arises is demonstrated here.

First, as shown in Fig. 9A, in the state where the suction valve 23 is open and the discharge valve 25 is closed, the air pressure of the electric regulator 28 is such that the bellows length becomes a predetermined length X. Control (Pin). At this time, with the rise of the air pressure Pin, the position of the bellows-type partition member 12 changes against the force of the compression coil spring 35 (the bellows 15 is extended in the example of illustration). .

Next, as shown in FIG.9 (b), the suction valve 23 and the discharge valve 25 are closed together, the pump chamber 13 is closed, and the air pressure of the electric regulator 28 in that state ( Set Pin) to 0. Then, the force which tries to return to an original state (no load state) acts on the compression coil spring 35. As shown in FIG. By the way, in the bellows-type partition member 12, the spring force F2 of the compression coil spring 35 acts downward of the figure, and the mixed air in the pump chamber 13 expands by the spring force F2. . As a result, the volume in the pump chamber 13 increases, and the bellows length varies by ΔX. By detecting this change in the bellows length with the position detector 36, air mixing can be determined. In addition, when air is not mixed in the pump chamber 13, the volume in the pump chamber 13 does not change even after setting the air pressure Pin of the electric regulator 28 to 0 ((DELTA) X = 0).

In the case of this embodiment, the fluctuation amount ΔX of the bellows length depends on the spring characteristics of the compression coil spring 35, and the fluctuation amount and the air volume become the relationship shown in FIG. By using FIG. 10, when the fluctuation | variation amount (DELTA) X of a bellows length is known, the air volume in the pump chamber 13 can be known.

According to the second embodiment described above, when air is mixed in the pump chamber 13 as in the first embodiment, the air mixing can be reliably detected. By the way, it becomes possible to perform the discharge supply of the chemical liquid by the chemical liquid pump 10 very appropriately.

In addition, this invention is not limited to description content of the said embodiment, You may implement as follows as an example.

In the above embodiment, when the continuous discharge is performed by the chemical liquid pump 10, air mixing is determined after the completion of the suction of the chemical liquid and until the next chemical liquid discharge is performed (see FIG. 6). This may be changed so that air mixing is determined after completion of discharging the chemical liquid and until the next chemical liquid suction is performed. That is, the air mixing determination is substituted for the air mixing determination after the completion of the suction of the chemical liquid, and the air mixing determination is performed before the suction start of the chemical liquid.

In the above embodiment, whenever the suction / discharge operation of the chemical liquid is repeated in the chemical liquid pump 10, the air mixing is determined every time, but the air mixing is determined when the suction / discharge operation is performed a predetermined time. You may also do it. Further, air mixing may be determined in accordance with an input instruction by an operator or the like.

In the above embodiment, when the air mixing is determined, the air pressure by the electro-pneumatic regulator 28 is gradually changed to the pressure reduction side, but instead of this, the same air pressure may be changed to the boosting side in stages. In addition, at the time of air mixing determination, you may make it change gradually the air pressure by the electro-pneumatic regulator 28 to the pressure reduction side or the pressure raising side.

In the said embodiment, when the air pressure in the pressure action chamber 14 is decompressed, the electric regulator 28 is made into the open air | atmosphere state, For example, the vacuum source is connected to the electric regulator 28, and the vacuum It is also possible to make the inside of the pressure action chamber 14 into negative pressure by a circular operation. By operation of such air pressure, the operation amount of bellows etc. can be arbitrarily controlled. In this case, it becomes possible to remove the compression coil spring 35 installed in the case main body 31.

In the above embodiment, as the chemical liquid pump 10, the pump chamber 13 and the pressure working chamber 14 are divided by the bellows-type partition member 12, and the bellows-type according to the air pressure in the pressure working chamber 14. Although the structure which operates the partition member 12 to perform suction and discharge of a chemical liquid is employ | adopted, it is also possible to use the chemical liquid pump of a structure different from this. For example, a diaphragm film may be used in place of the bellows-type partition member 12 as the variable volume member. The volume variable member may be an electric piston member, and the piston position may be adjusted by driving of the motor or the like.

In the above embodiment, as a specific example of a chemical liquid supply system including a plurality of chemical liquid pumps, a plurality of chemical liquid pumps are assembled and connected between the respective pumps by piping or the like, but the pumps in which the plurality of chemical liquid pumps are integrated A unit may be employed. Thereby, it is also possible to reduce piping and the like and to save space.

The present invention reliably detects gas mixture in the pump chamber of the chemical liquid pump, and can discharge and supply the chemical liquid by the chemical liquid pump very suitably.

Claims (16)

A chemical liquid pump having a pump chamber for filling the chemical liquid and a volume variable member for changing the volume of the pump chamber, and sucking or discharging the chemical liquid based on a change in volume of the pump chamber by the volume variable member; Actuating means for actuating the variable volume member, Operation amount detecting means for detecting an operation amount of the variable volume member, Displacement operation means for performing a displacement operation to change the position of the variable volume member by the operation means in a state where the chemical liquid entrance to the pump chamber is closed, and And the judging means for judging the presence or absence of gas in the pump chamber on the basis of the operation amount detection result by the operation amount detecting means in the displacement operation means. The method of claim 1, The chemical liquid pump has a pressure working chamber which is divided in the pump chamber by the volume variable member, and the volume variable member is operated by adjusting the gas pressure in the pressure working chamber by the operating means, The displacement operation means performs the displacement operation of the volume variable member by adjusting the gas pressure in the pressure working chamber by the operation means. The method of claim 1, In the suction or discharge of the chemical liquid by the chemical liquid pump, the target operation amount of the variable-volume member is set and the actual operation amount required in the detection result by the operation amount detection means coincides with the target operation amount. The chemical liquid supply system further comprising a feedback control means for feedback-controlling the operating state of the operating means. The method of claim 1, The chemical liquid supply system which estimates the amount of gas in the said pump chamber based on the operation amount detection result by the said actuation amount detection means at the time of determining the presence or absence of the gas in the said pump chamber. The method of claim 1, The chemical liquid stored in the storage container is supplied to the chemical liquid pump through the chemical liquid pipe, A chemical liquid supply system according to the present invention, upon determining the presence or absence of gas in the pump chamber, determines that the chemical liquid stored in the storage container has become a predetermined amount or less on the basis of the operation amount detection result by the operation amount detection means. The method of claim 1, In the case where the single pump chamber is included, the suction or discharge of the chemical liquid is alternately repeated in the pump chamber, When the plurality of pump chambers are included, the plurality of pump chambers are used in a predetermined order to perform suction and discharge operations, The determination means determines the presence or absence of gas in the pump chamber after the completion of the suction of the chemical liquid in each pump chamber and until the next discharge of the chemical liquid, or after the completion of the discharge and the subsequent chemical liquid suction. Chemical liquid supply system, characterized in that. The method of claim 6, A volume change operation of the pump chamber by the volume variable member is performed faster at the time of chemical liquid suction than at the time of chemical liquid discharge. The method of claim 1, And a means for notifying when gas is introduced into the pump chamber by the judging means. A pump chamber for filling the chemical liquid, a volume variable member for varying the volume of the pump chamber, and a biasing means for biasing the volume variable member in a predetermined direction, and operating the volume variable member against the biasing force of the biasing means. And a chemical liquid pump which sucks or discharges the chemical liquid based on the volume change of the pump chamber with the operation, Actuating means for actuating the volume varying means, Operation amount detection means for detecting an operation amount of the volume varying means, In the state where the chemical liquid suction port leading to the pump chamber is opened, displacement operation of the variable volume member by the operating means is performed against the force of the biasing means, after which the pump chamber is sealed and at the same time by the operating means Displacement manipulation means for releasing displacement manipulation of the volume variable member, and And determining means for determining the presence or absence of gas in the pump chamber based on the operation amount detection result by the operation amount detection means after the displacement operation of the volume variable member is released by the displacement operation means. Chemical supply system. The method of claim 9, The chemical liquid pump has a pressure working chamber which is divided in the pump chamber by the volume variable member, and the volume variable member is operated by adjusting the gas pressure in the pressure working chamber by the operating means, And the displacement operation means performs displacement operation of the volume variable member by adjusting the gas pressure in the pressure working chamber by the operation means. The method of claim 9, At the time of suction or discharge of the chemical liquid by the chemical liquid pump, while setting a target operation amount of the variable volume member, the actual operation amount required in the detection result by the operation amount detection means coincides with the target operation amount. And a feedback control means for feedback controlling the operating state of the operating means. The method of claim 9, The chemical liquid supply system which estimates the amount of gas in the pump chamber based on an operation amount detection result by the operating amount detecting means when determining the presence or absence of gas in the pump chamber. The method of claim 9, The chemical liquid stored in the storage vessel is supplied to the chemical liquid pump through the chemical liquid pipe, A chemical liquid supply system according to the present invention, upon determining the presence or absence of gas in the pump chamber, determines that the chemical liquid stored in the storage container has become a predetermined amount or less on the basis of the operation amount detection result by the operation amount detection means. The method of claim 9, In the case where the single pump chamber is included, the suction or discharge of the chemical liquid is alternately repeated in the pump chamber, When the plurality of pump chambers are included, the plurality of pump chambers are used in a predetermined order to perform suction and discharge operations, The judging means judges the presence or absence of gas in the pump chamber during the completion of the suction of the chemical liquid in each pump chamber until the next chemical liquid discharge is performed or the completion of the discharge of the chemical liquid after the discharge completion. Chemical liquid supply system. The method of claim 14, A volume change operation of the pump chamber by the volume varying means is performed faster at the time of chemical liquid suction than at the time of chemical liquid discharge. The method of claim 9, And a means for notifying when gas is introduced into the pump chamber by the judging means.

Images