JP2001000931A - Method and system for supplying chemical liquid and apparatus for cleaning substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To formulate a supply liquid (cleaning liquid) of an exact chemical liquid concentration, especially an extremely low concentration, simply and promptly as required and to supply the liquid. SOLUTION: A chemical liquid supply system 2 is composed of a dilute solution supply part 2a which has a chemical liquid storage tank in which a chemical liquid for cleaning is stored in a raw liquid state and a liquid supply pump, supplies the chemical liquid positively, and produces a dilute solution of a concentration of an intermediate stage and a cleaning liquid supply part 2b which has a dilute solution storage tank for storing the dilute solution supplied from the part 2a and a liquid supply pump 31b, supplies the dilute solution positively, produces a cleaning liquid of an extremely low concentration (ppm ordor) of a final stage, and supplies it to a wafer 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical solution supply system and method for accurately supplying a desired amount of a chemical solution, and is particularly suitable for use in a substrate cleaning apparatus for cleaning semiconductor wafers and the like.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor wet process, a substrate cleaning apparatus for performing processing such as cleaning with a cleaning liquid composed of ultrapure water or a chemical solution is used. As such a substrate cleaning apparatus, a single-substrate spin cleaning apparatus which is attached to each substrate and supplies a cleaning liquid while rotating the substrate in a circumferential direction has attracted attention.

[0003]

In the conventional substrate cleaning apparatus, it is essential to provide a plurality of large-sized cleaning liquid storage tanks for preparing various chemical solutions required for cleaning at desired concentrations. Therefore, in this case, the whole apparatus is necessarily extremely large-scale and complicated.

[0004] Further, various concentrations of cleaning liquids are required, and a dilute cleaning liquid having an extremely low concentration is particularly indispensable. In order to accurately generate and supply such a cleaning solution having a low concentration from a very low concentration to a low concentration, for example, a low concentration from ppm to 0.1%, the lower the concentration, the more accurately the chemical solution (stock solution) is weighed. It is indispensable to perform the concentration control. To this end, an extremely large-scale and complicated device is inevitably required, and extremely elaborate and complicated work is required to dilute the chemical solution to a desired extremely low concentration.

As described above, at present, it is difficult to avoid an increase in the size and complexity of the entire substrate cleaning apparatus, to prevent particles from being mixed into the cleaning liquid, and to easily and accurately use a very low-concentration diluted cleaning liquid. There is a strong demand for the establishment of a technology that enables generation.

Accordingly, an object of the present invention is to significantly reduce the size and simplification of a cleaning liquid supply system including a storage tank for a chemical liquid or the like, and to provide a correct concentration of a chemical liquid when necessary, particularly, a supply liquid having a very low concentration (cleaning liquid). It is an object of the present invention to provide a chemical solution supply system and method, and a substrate cleaning apparatus, which enable simple and quick preparation and supply of a chemical solution.

[0007]

A chemical solution supply system according to the present invention is a chemical solution supply system for mixing and diluting at least one kind of chemical solution with a solvent and supplying a final adjusted solution concentration to a predetermined chemical solution. A first storage tank in which the high-concentration chemical solution is stored, a first supply unit that suctions and sends a predetermined amount of the chemical solution from the first storage tank, and the first supply unit. A first discharge unit that forms a connected flow path of the solvent, and has a first discharge unit that discharges a diluted solution obtained by mixing and diluting the chemical solution with the solvent and adjusting the concentration to a predetermined chemical solution concentration higher than the supply liquid; A second storage tank in which the diluted solution is stored, and a predetermined amount of the diluted solution stored in the second storage tank.
A second supply means for sucking and sending out from the storage tank, and forming a flow path of the solvent to which the second supply means is connected,
A second piping system having a second discharge unit that discharges the supply liquid whose concentration is adjusted by further mixing and diluting the diluting solution with the solvent, and driving the first supply unit to supply a required amount of the second liquid. A chemical solution is mixed with the solvent flowing in the first piping system to generate the diluted solution, and the diluted solution is discharged from the first discharge unit and stored in the second storage tank. And a required amount of the diluting solution is mixed with the solvent flowing in the second piping system by driving the second supply means to generate the supply liquid having a desired concentration, and the second discharge unit Supplied from

[0008] A chemical solution supply system of the present invention is a chemical solution supply system for mixing and diluting at least one kind of chemical solution with a solvent to supply a supply solution adjusted to a final predetermined chemical solution concentration. A first storage tank in which a drug solution is stored, a first supply unit that sucks a predetermined amount of the drug solution from the first storage tank and sends out the solution, and a drug solution that is sent from the first supply unit. A second storage tank in which a diluted solution prepared by mixing and diluting with the solvent and adjusting to a predetermined chemical solution concentration higher than the supply liquid is stored, and a predetermined amount of the diluted solution is sucked from the second storage tank. Second supply means for transmitting
A pipe system configured to form a flow path of the solvent to which the second supply means is connected, and to discharge the supply liquid whose concentration is adjusted by further mixing and diluting the diluted solution with the solvent from an end portion, By driving the first and second supply means, the supply liquid having a predetermined concentration generated by performing stepwise dilution of the chemical liquid using the first and second storage tanks is supplied.

In one embodiment of the chemical solution supply system according to the present invention, a flow path of the solvent connected to the first supply means is formed, and the diluted solution mixed and diluted with the solvent in the flow path is supplied to the first solution. 2 is provided with another piping system for discharging to the storage tank.

[0010] One embodiment of the chemical solution supply system of the present invention is provided with another piping system for forming the flow path of the solvent and discharging the solvent to the second storage tank. The chemical solution is mixed and diluted with the solvent to generate the diluted solution.

In one embodiment of the chemical liquid supply system according to the present invention, the first and second supply means are provided with a flow path for passing the dilute solution and the chemical liquid, and the diluent solution is provided at an inlet of the flow path. A liquid supply pump in which a suction valve that closes due to a rise in the pressure of the chemical solution is provided with a discharge valve that closes due to a decrease in the pressure of the diluting solution and the chemical solution at an outlet of the flow path, At least a part of the liquid surface is made of a dense member that is impervious to the chemical solution and has high corrosion resistance, and a part of the dense member is a movable wall, including a vibrator connected to the movable wall, By driving the vibrator, the movable wall is vibrated in a direction substantially orthogonal to the wall surface to periodically change the volume of the flow path.

One embodiment of the chemical liquid supply system according to the present invention includes connection paths for connecting the respective piping systems and the respective supply means, and is directly connected to the respective piping systems in the respective connection paths.
A thin tube member is provided as a discharge site of the chemical solution or the diluted solution to the solvent.

One embodiment of the chemical solution supply system of the present invention includes a control system for adjusting the supply solution to be supplied.

[0014] One embodiment of the chemical solution supply system according to the present invention is provided in the first storage tank, wherein the storage amount of the chemical solution is measured to calculate the chemical concentration of the diluted solution in the second storage tank. And a second concentration measuring means provided in the second storage tank and measuring a storage amount of the diluted solution to calculate a chemical concentration of the supply liquid.

One embodiment of the chemical solution supply system of the present invention is provided in the first storage tank, wherein the storage amount of the chemical solution is measured to calculate the chemical concentration of the diluted solution in the second storage tank. A second concentration measuring means provided in the second storage tank and measuring a storage amount of the diluted solution to calculate a chemical concentration of the supply liquid; Controlling the drive of the second supply means with reference to the calculated value of the chemical concentration of the diluted solution by the first concentration measuring means and the calculated value of the chemical concentration of the supply liquid by the second concentration measuring means. The discharge amount and discharge speed of the diluted solution from the second supply means are adjusted to control the chemical concentration of the supply liquid to a target value.

In one embodiment of the chemical solution supply system according to the present invention, the first and second concentration measuring means include a conductive member,
Alternatively, it has a pair of rod-shaped sensors made of a member that is insulated and coated with a fluororesin or the like, and by measuring the electric capacity of the immersion part in the chemical solution and the diluting solution of the rod-shaped sensor and its time change, This is a liquid level meter that obtains the liquid surface heights of a chemical solution and the dilute solution and the rate of change thereof to calculate the chemical solution concentration.

In one embodiment of the chemical solution supply system of the present invention, the first and second concentration measuring means measure the weights of the chemical solution and the dilute solution and changes thereof, and calculate the concentration of the chemical solution by a weighing scale. is there.

A substrate cleaning apparatus according to the present invention is a substrate cleaning apparatus for supplying a cleaning liquid to an installed substrate and cleaning the substrate, comprising the chemical liquid supply system, and using the supply liquid as the cleaning liquid.

The chemical solution supply method of the present invention is a chemical solution supply method for mixing and diluting at least one kind of chemical solution with a solvent and supplying a supply solution adjusted to a final predetermined chemical solution concentration,
By driving the first supply means, the first liquid in which the chemical is stored
Mixing and diluting a required amount of the chemical solution from the storage tank with the solvent flowing in the first piping system to generate a dilute solution adjusted to a predetermined chemical solution concentration higher than the supply liquid; Is stored in a second storage tank, and a required amount of the diluting solution is further mixed and diluted from the second storage tank with the solvent flowing in a second piping system by driving a second supply unit. Then, the supply liquid having a predetermined chemical concentration is generated and supplied.

In one embodiment of the method for supplying a chemical solution according to the present invention,
The first and second supply means are formed with a flow path through which the diluted solution and the chemical solution pass, and a suction valve that closes at an inlet of the flow path due to an increase in the pressure of the diluted solution and the chemical solution, the suction valve closes the flow path. A liquid supply pump in which a discharge valve that is closed by a pressure drop of the diluting solution and the chemical solution is provided at an outlet of a path, wherein at least a part of a liquid contact surface in the flow path is impermeable to the chemical solution and A high-corrosion dense member is provided, and a part of the dense member is a movable wall, and includes a vibrator connected to the movable wall,
By driving the vibrator, the movable wall is vibrated in a direction substantially orthogonal to the wall surface to periodically change the volume of the flow path.

[0021]

In the chemical liquid supply system according to the present invention, the chemical liquid is mixed, for example, from a thin tube member into a solvent typified by ultrapure water passing through the supply flow path by driving the first and second supply means. Feed solutions of various concentrations can be easily prepared as needed. Here, when the discharge direction of the chemical solution is a direction substantially orthogonal to the flow direction of the solvent,
By applying a pressure to the chemical liquid such that the linear velocity of the chemical liquid discharged from the thin tube member is desirably greater than the linear velocity of the solvent passing through the supply channel, the supply liquid having a uniform desired concentration in the solvent can be easily formed. Will be compounded.

When the finally required concentration of the chemical solution is a value from an extremely low concentration to a low concentration (for example, a low concentration from ppm to 0.1%), the required amount of the chemical solution is first driven by driving the first supply means. Is sucked from the first storage tank and delivered to the solvent passing through the first piping system. Here, the chemical solution is diluted to a predetermined concentration in the first stage, and is stored in the second storage tank as a dilute solution having an intermediate concentration. Subsequently, a required amount of the diluted solution is sucked from the second storage tank by the driving of the second supply means, and is sent to the solvent passing through the second piping system. Here, the diluted solution is diluted to a predetermined concentration in the second stage (final stage) and supplied to, for example, a substrate as a cleaning liquid. As described above, the chemical solution concentration adjustment at each stage is performed precisely and precisely by the precise driving of each supply unit, so that even if the finally required supply solution (cleaning solution) has an extremely low concentration, it is accurately generated. It becomes possible.

As the first and second supply means, a liquid supply pump is suitable. The liquid supply pump drives and vibrates the movable wall by a vibrator, and discharges a chemical liquid by pressing the movable wall. The liquid supply pump can discharge and supply a desired amount of the chemical liquid accurately. Here, at least a part of the liquid contact surface is made of a dense member that is impermeable to the chemical solution and has high corrosion resistance, preferably amorphous carbon. This amorphous carbon is a material whose porosity can be easily controlled, and those having a porosity of almost 0 exhibit extremely excellent impermeability and high corrosion resistance. Therefore, by providing this amorphous carbon in an important part of the liquid contact surface, the supply amount control of the chemical solution becomes more accurate, and the mixing of particles and the like into the chemical solution is suppressed. Further, even if a fluorine resin material is used instead of amorphous carbon, it can be practically used depending on the type of the chemical.

Further, in this chemical supply system, a supply liquid having a desired concentration can be generated as required as described above, so that the first storage tank for the chemical liquid as a stock solution and the second storage for the diluted solution are prepared. Both tanks need to be small and easy to move. That is, it is not necessary to prepare a storage tank for a very large supply liquid having a different concentration or type of chemical solution as in the related art, and it becomes easy to generate a supply liquid of a desired extremely low concentration, and it is possible to prevent particles from being mixed into the supply liquid. Not only that, the scale of the entire system can be significantly reduced and simplified. Therefore, by applying this chemical liquid supply system to, for example, a substrate cleaning apparatus, it becomes possible to quickly and easily supply various clean cleaning liquids having different concentrations and types.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific embodiment of the substrate cleaning apparatus of the present invention will be described in detail with reference to the drawings. The substrate cleaning apparatus according to the present embodiment is mounted on each wafer, and supplies a cleaning liquid while rotating the wafer in a circumferential direction, and is capable of realizing a wide range of functions in a wet cleaning process of a semiconductor wafer or the like. It is a spin cleaning device.

FIG. 1 is a schematic diagram showing the overall configuration of a substrate cleaning apparatus according to the present embodiment. The substrate cleaning apparatus is provided with a cleaning chamber 1 in which a substrate (wafer) 11 is installed and cleaning is performed, and a chemical solution supply system 2 that generates and supplies a cleaning solution having a desired chemical solution concentration.

[0027] As shown in FIG.
A closed space for accommodating the wafer 11 to be cleaned is formed, and a gate valve 12 serving as a portion for carrying in / out the wafer 11 is provided. The cleaning chamber 1 has wafer holding pins 13 for holding the wafer 11 from the side, a wafer setting means 14 having a rotation drive motor for rotating the fixed wafer 11 in the direction of the arrow in FIG. Means 1
The cleaning liquid collision buffer plate 15 is provided so as to surround the cleaning liquid 4 from the side. Here, the cleaning liquid collision buffer plate 15 is not always necessary, and the role of the cleaning liquid collision buffer plate 15 can be replaced by providing the cleaning chamber with a slightly curved surface.

The cleaning chamber 1 is provided with a nozzle (not shown) for supplying an N ₂ gas or an inert gas, and the like. Alternatively, the wafer 11 is dried by rotating at a high speed while simultaneously spraying N ₂ gas or the like on the front and back surfaces, or the wafer 11 is washed while the inside of the washing chamber 1 is replaced with a high concentration of N ₂ gas or an inert gas. You can do things.

A chemical solution supply system 2 dilutes a stock solution (chemical solution) and adjusts the concentration in a first stage (intermediate stage), and further dilutes the diluted solution produced here to a second solution. And a cleaning liquid supply unit 2b for performing a concentration adjustment at the stage (final stage).

As shown in FIG. 3, the diluting solution supply unit 2a includes a chemical storage tank (first storage tank) 121 in which a cleaning chemical is stored in the form of a stock solution, and a chemical storage tank 121.
Liquid supply device 1 that is connected to
22 is connected to the chemical solution supply device 122 to form a supply channel that serves as a passage for ultrapure water into which the chemical solution is mixed (first piping system).
And a piping system 123).

The cleaning liquid supply unit 2b is connected to a diluting solution storage tank (second storage tank) 21 for storing the diluting solution supplied from the discharge unit 123c of the piping system 123, and to the diluting solution storage tank 21 for dilution. A diluting solution supply device 22 that actively supplies a solution, and a piping system (second piping system) that is connected to the diluting solution supply device 22 and forms a supply flow path that serves as a passage for ultrapure water into which the diluting solution is mixed. And 23) a pair of discharge nozzles 24 and 25 provided at an end of the piping system 23 to face each surface of the wafer 11 installed in the cleaning chamber 1 and supplying a cleaning liquid to each surface. In addition to adjusting the concentration in the solution supply unit 2a,
And a control system 26 for adjusting various states such as the concentration and the flow rate of the cleaning liquid supplied from the control unit 25.

The chemical solution storage tank 121 stores a high-concentration chemical solution in the form of a stock solution, for example, hydrofluoric acid (HF) or ammonium hydroxide (NH ₄ OH).
It is a small size that is easy to move in and out. A plurality of chemical storage tanks 121 may be provided depending on the type of the chemical and the like.

The diluted solution storage tank 21 is provided corresponding to each of the chemical solution storage tanks 121 and stores a diluted solution diluted to a first concentration (intermediate stage) diluted to a desired concentration. It is. The dilute solution storage tank 21 is also of a small size that can be easily moved in and out, but may be of an installation type for both the chemical solution storage tank 121 and the dilute solution storage tank 21.

The chemical storage tank 121 and the diluent storage tank 21 are provided with liquid level gauges 49 for measuring the level of the supplied chemical and diluent solutions to control the liquid levels. As shown in FIG. 4, the liquid level meter 49 is a pair of rod-shaped sensors made of, for example, carbon. As described below, the liquid level is measured by measuring the capacitance of the cleaning liquid between the rod-shaped sensors 49a and 49b. This is to obtain the surface height.

Here, the principle of measuring the liquid level by the liquid level meter 49 will be described. Assuming that the distance from the liquid level of the cleaning liquid to the lower end of the rod-shaped sensor is L and the distance between the rod-shaped sensors is D, r1, r2, a, d, and δ are defined as shown in FIG. In this case, δ / a = a / d = r1 / r2 holds, so that + Q is charged in circle 1 (cross section of one bar sensor) and −Q is charged in circle 2 (cross section of the other bar sensor). If there is, for all points of one bar sensor, (Q / L) 2πε ₀ (ln (r1) −ln (r2)) =
(Q / L) 2πε ₀ ln (r1 / r2) = (Q / L) 2
πε ₀ ln (a / d) holds. The electric charge Q distributed on the straight line 1-2 generates the same electric field outside the rod-shaped sensor as when the same amount of electric charge exists on the surface of the rod-shaped sensor. Therefore, the potential difference between the two rod-shaped sensors is (Q / L) The capacitance C is equal to πε ₀ ln (a / d), and the capacitance C is as follows: C = πε ₀ L / ln (a / d) (1)

In the equation (1), a / d = exp (πε ₀ L /
C), D / a = exp (πε ₀ L / C) + exp (−πε ₀ L
/ C) = 2 cosh (πε ₀ L / C), and C = πε ₀ L / (cosh ⁻¹ D / 2a) (2) holds. From the equation (2), the value of L can be obtained by measuring the value of C.

As described above, according to the liquid level meter 49, the liquid level and its change are measured by measuring the electric capacitance of the rod-shaped sensors 49a and 49b at the immersion site in the chemical solution and the diluting solution and its time change. You can get speed. In other words, by using the liquid level as a parameter, it is possible to adjust the liquid level to a desired value by measuring a deviation from the desired value, for example, and to use the rate of change of the liquid level as a parameter. This measures the increase in the rate of change. Accordingly, the liquid level gauge 49 efficiently and reliably measures the liquid level of the chemical solution and the dilute solution and the rate of change thereof. From the result, when the liquid level meter 49 is provided in the chemical solution storage tank 121, The storage amount of the chemical solution is measured to calculate the chemical concentration of the diluted solution in the diluted solution storage tank 21, and when provided in the diluted solution storage tank 21, the storage amount of the diluted solution is measured to calculate the chemical concentration of the cleaning solution. It is possible to do. As a result, the supply of the chemical solution and the diluent solution as needed, and the occurrence of various inconveniences associated with the supply of the chemical solution and the diluent solution can be reliably detected.

FIG. 6 shows the result of actually examining the relationship between the liquid level and the volume of the chemical solution. FIG. 6 shows the relationship between the value calculated by equation (2) and the actually measured value. Here, the actual measured value is ε ₀ =
7.17 × 10 ⁻¹⁰ F / m, radius of rod-shaped sensor = 2 m
m, separation distance = 10 mm, length of rod-shaped sensor = 31.0
mm, and the calculated value was calculated under the same conditions. In this characteristic diagram, the horizontal axis represents the liquid level of the chemical (0 when full).
mm) and the vertical axis represents the capacitance (nF). As described above, the calculated value and the measured value substantially match, and it is understood that C and L are in a proportional relationship.

The chemical solution supply device 122 is a liquid supply pump 31 which is a diaphragm pump for performing an operation of vibratingly sending a chemical solution from the chemical solution storage tank 121 by utilizing a piezoelectric effect.
a, a connecting pipe 132 that connects the piping system 123 and the liquid supply pump 31a to form a connecting flow path, and a thin tube member (capillary) 33 that is directly connected to the supply flow path of the piping system 123 in the connecting pipe 132. It is provided with.

Similarly, the diluting solution supply device 22 supplies the diluting solution from the diluting solution storage tank 21 to the liquid supply pump 3.
1b, a connection pipe 32 connecting the piping system 23 and the liquid supply pump 31b to form a connection flow path, and a capillary 33 directly connected to the supply flow path of the piping system 23 in the connection pipe 32. Have been.

As shown in FIGS. 7 to 9, the liquid supply pumps 31a and 31b are formed with a flow path 41 through which a chemical solution passes. A discharge valve 43 is provided at the outlet of the flow path 41 and closed by the pressure drop of the chemical solution. Here, a pair of opposing side walls 44 and 45 that constitute a part of the liquid contact surface in the flow path 41 are made of a dense member that is impermeable to a chemical solution and has high corrosion resistance. And the side wall 44 is a movable wall.

Then, the liquid supply pumps 31a, 31b
Is connected to the side wall (movable wall) 44 and the movable wall 44
Is vibrated in a direction substantially perpendicular to the wall surface, and the volume of the flow path 41 is periodically changed.
And a drive transmitting means 47 provided between the movable wall 44 and the piezoelectric vibrator 46 for transmitting the vibration from the piezoelectric vibrator 46 to the movable wall 44, and the piezoelectric vibrator 46 cannot generate pressure in the contraction direction. The drive transmission means 4
And a spring 48 for resiliently biasing the spring 7.

Amorphous carbon, which is the main material of the side walls 44 and 45, has impermeability and high corrosion resistance as described above, and is a chemical solution used for cleaning the wafer 11, especially hydrofluoric acid or hydrogen peroxide. It has the property of not being polluted by oxidizing agents such as water and ozone. The amorphous carbon used here is preferably a homogeneous amorphous carbon, a fibrous amorphous carbon, or a composite material of both. Homogeneous amorphous carbon has a dense isotropic structure without porosity, is a material excellent in gas barrier properties and liquid barrier properties, and can control porosity according to the application. The fibrous amorphous carbon is a porous carbon having a three-dimensional skeletal structure, and is a porous carbon having uniform pores.

The conventional chemical liquid supply system constructed of a fluororesin has a defect that diffusion of a small amount of HF cannot be suppressed in a long term because diffusion of HF molecules in the fluororesin cannot be avoided. This problem can be solved by applying amorphous carbon to the liquid contact part as in the present embodiment.

The operation of the liquid supply pumps 31a and 31b is as follows. When the movable wall 44, which is a diaphragm, moves to the right in FIG. 9, the flow path 41 becomes negative pressure and the discharge valve 43 is closed, and when it moves to the left as shown in FIG. As a result, the suction valve 42 is closed and the discharge valve 43 is opened to discharge the chemical. Here, it is preferable to control the frequency of the movable wall 44 by driving the piezoelectric vibrator 46 to, for example, about 20 Hz, and the discharge pressure of the chemical solution is, for example, 1.5 kg / c.
m ² or more is preferable.

The capillary 33, which is a thin tube member, is mainly made of the same amorphous carbon as the side walls 44 and 45, and has a tube diameter of, for example, about 0.2 mm and a discharge rate of, for example, 0.3 cc / sec. The chemical liquid is discharged from the capillary 33 into the ultrapure water in the piping system 23 by the vibration drive of the liquid supply pump 31.

The piping system 123 forms a supply flow path of ultrapure water as described above, and has a pipe diameter of, for example, about 5 mm and a flow rate of, for example, about 1.0 liter / minute. Similarly, the piping system 23 also forms a supply flow path of ultrapure water as described above, and has a pipe diameter of, for example, about 5 mm, and a flow rate of, for example, about 2 liters / minute. These piping systems 123, 23
And a mixing means 36 arranged at a connection portion of the piping systems 123 and 23 with the capillary 33, for generating a rotating flow in the cleaning liquid and agitating the same to make the cleaning liquid uniform.

The control system 26 includes chemical liquid supply control means 37 for adjusting the supply amount of the chemical liquid to the ultrapure water and the supply amount of the diluting solution to the ultrapure water of each liquid supply pump 31. The measurement / calculation results of the scale 49 and the weighing scale 200 are fed back to the chemical liquid supply control means 37 to control the liquid supply pumps 31a and 31b, and the supply amounts of the chemical liquid and the dilute solution are adjusted.

Hereinafter, a specific operation of the substrate cleaning apparatus of the present embodiment will be described. In the present embodiment, the control system 26
Is determined by referring to the calculated value of the chemical concentration of the diluted solution by the liquid level system 49 provided in the chemical storage tank 121 and the calculated value of the chemical concentration of the cleaning liquid by the liquid level system 49 provided in the diluted solution storage tank 21. The supply pump 31b is driven and controlled, and the discharge amount and discharge speed of the diluting solution from the liquid supply pump 31b are adjusted to control the chemical concentration of the cleaning liquid to a target value. Here, a case where the target value of the chemical concentration of the diluted solution is 90 ppm and the target value of the chemical concentration of the final cleaning liquid is 0.8 ppm will be exemplified.

First, for example, ammonium hydroxide (NH ₄
Chemical storage tank 1 storing a chemical containing 30% OH)
21 and the valves 123a, 123 of the piping system 123.
b is sequentially opened. Next, the liquid supply pump 31a is driven by the control system 26, and four shots of 0.015 cc are taken at one time.
(0.06 cc in total), and each shot is sent from the capillary 33 to ultrapure water passing through the piping system 123 and mixed by the mixing means 36. At this time, the piping system 1
The ultrapure water in 23 flows for a predetermined time including the four shots, and is discharged from the discharge part 123c to the diluted solution storage tank 21, and then the valve 123b is closed. Here, the control is performed so that 200 cc of ultrapure water is discharged in the predetermined time.
A dilute solution of 90 ppm NH ₄ OH in cc is stored.

Here, the delivery amount of the chemical from the chemical storage tank 121 is determined by the liquid level meter 49 provided in the chemical storage tank 121.
And the diluted solution storage tank 2
The amount of the chemical in 1 is known.

Subsequently, the liquid supply pump 3 is controlled by the control system 26.
By driving 1b, the diluted solution is sent from the capillary 33 to ultrapure water passing through the piping system 23, and mixed by the mixing means 36. At this time, the flow rate of the ultrapure water passing through the piping system 23 is adjusted to 2 liters / minute by the flow rate adjusting means 34, and the sending speed of the diluted solution of the liquid supply pump 31b is set to 0.3 cc in response to this. / Sec (20 Hz). As a result, 0.8 ppm of N
A cleaning liquid precisely adjusted to an extremely low concentration of H ₄ OH is generated, discharged from the discharge nozzles 24 and 25, and supplied to the surface of the wafer 11.

Here, the delivery amount of the dilute solution from the dilute solution storage tank 21 is measured by the liquid level meter 49 provided in the dilute solution storage tank 21.

For example, assuming that the concentration of the diluted solution in the diluted solution storage tank 21 is
Even when the value calculated by the liquid level meter 49 installed in 1 is different from the target value, it is possible to adjust the final chemical concentration of the cleaning liquid to the target value by controlling the driving of the liquid supply pump 31b of the control system 26. is there.

Specifically, as shown in FIG. 11, when the calculated value is 80 ppm (the target value is 90 ppm),
In order to achieve the target value (0.8 ppm) of the chemical concentration of the cleaning liquid, the amplitude of the movable wall (diaphragm) 44 of the liquid supply pump 31b is changed by the control of the control system 26, and the sending speed of the diluted solution in the liquid supply pump 31b is reduced. Fine adjustment is made to be 0.34 cc / sec (20 Hz). Thereby, the deviation of the calculated value from the target value is interpolated, and the density 0.8 p
A cleaning liquid precisely adjusted to an extremely low concentration of NH ₄ OH of pm will be generated and supplied.

As described above, in the substrate cleaning apparatus of the present embodiment, first, the piezoelectric vibrator 46 drives and vibrates the movable wall 44 by the liquid supply pumps 31a and 31b, and presses the liquid crystal and the diluting solution by the pressure. To discharge,
It is possible to accurately discharge and supply a desired amount of a chemical solution and a diluted solution. Here, at least a part of the liquid contact surface is made of a dense member that is impermeable to the chemical solution and has high corrosion resistance, preferably amorphous carbon. This amorphous carbon is a material whose porosity can be easily controlled, and those having a porosity of almost 0 exhibit extremely excellent impermeability and high corrosion resistance. Therefore, by providing this amorphous carbon in an important part of the liquid contact surface, the supply amount control of the chemical solution becomes more accurate, and the mixing of particles and the like into the chemical solution is suppressed.

In this embodiment, the liquid supply pump 31
Provided is a chemical liquid supply system including a and 31b as constituent elements. In this chemical supply system, the liquid supply pump 3
By driving 1a and 31b, cleaning solutions of various concentrations can be easily prepared as needed. Here, when the discharge direction of the chemical solution and the dilute solution is a direction substantially orthogonal to the flow direction of the ultrapure water, the linear velocity of the chemical solution and the dilute solution discharged from the capillary 33 is changed to the ultrapure water flowing through the supply flow path. By applying a pressure that is desirably greater than the linear velocity to the chemical solution and the diluting solution, a uniform desired concentration of the cleaning liquid can be easily prepared.

When the finally required concentration of the chemical solution is a value from an extremely low concentration to a low concentration (for example, a low concentration from ppm to 0.1%), the required amount of the chemical solution is first driven by driving the liquid supply pump 31a. Suction from chemical solution storage tank 121 and piping system 1
It is sent to ultrapure water passing through 21. Here the chemical is the first
The diluted solution is diluted to a predetermined concentration in the step, and is stored in the diluted solution storage tank 21 as a diluted solution having an intermediate concentration. Subsequently, the required amount of the dilute solution is sucked from the dilute solution storage tank 21 by driving the liquid supply pump 31b, and is sent to the ultrapure water passing through the piping system 21. Here, the diluted solution is diluted to a predetermined concentration in the second stage (final stage) and supplied to the wafer 11 as a cleaning liquid. As described above, the chemical solution concentration adjustment at each stage is performed precisely and precisely by the precise driving of each of the liquid supply pumps 31a and 31b, so that even if the finally required cleaning solution has an extremely low concentration, it is accurately generated. It becomes possible.

Further, in this chemical supply system, since the cleaning liquid having a desired concentration can be generated as required as described above, both the chemical storage tank 121 and the diluent storage tank 21 for the undiluted chemical are easily movable. A small thing is enough. That is, it is not necessary to prepare a very large storage tank having a different chemical solution concentration or type as in the conventional case, and it is easy to generate a cleaning liquid having a desired extremely low concentration. The overall scale is greatly reduced and simplified, and it becomes possible to quickly and easily supply various clean cleaning liquids having different concentrations and types.

-Modification- Here, a modification of the substrate cleaning apparatus of the present embodiment will be described. In this modification, a substrate cleaning apparatus having substantially the same configuration as that of the present embodiment will be described.
1 and the dilute solution storage tank 21 are different in that the storage modes are slightly different.

That is, in this modification, as shown in FIG.
A weigh scale 200 is provided in place of the liquid level meter 49, and the weight of each of the storage tanks 121 and 21 is measured so that the amount of the chemical solution delivered from the chemical solution storage tank 121 and the dilution solution storage tank 2 are measured.
The diluted solution delivery amount from 1 is measured, and the chemical concentrations of the diluted solution and the cleaning solution are calculated as in the case where the liquid level meter 49 is provided.

Here, since each weighing scale 200 is exposed to the vapor of a chemical solution (or a diluting solution), its surface is coated with a highly corrosion-resistant member such as a fluororesin to prevent corrosion.

Although not shown in the figure, in the diluting solution supply section 2a, a predetermined amount of the chemical is supplied from the liquid supply pump 31a to the diluting solution storage tank 21 without passing through the piping system 123, and from the piping system 123. A predetermined amount of ultrapure water may be supplied and mixed and diluted, and a diluted solution may be generated in the diluted solution storage tank 21. Also in this case, the liquid level meter 49 or the weighing scale 200 may be used to measure the respective concentrations of the diluted solution and the cleaning solution.

The present invention is not limited to this embodiment. For example, the chemical solution supply system is applicable not only to a substrate cleaning device but also to any other device requiring a large amount of various types and concentrations of chemical solutions.

[0065]

According to the present invention, the cleaning liquid supply system including the storage tank for chemicals and the like can be significantly reduced in size and simplified, and
When necessary, it is possible to easily and quickly prepare and supply a supply liquid (cleaning liquid) having an accurate chemical solution concentration, particularly an extremely low concentration.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating an example of a single wafer spin cleaning apparatus including a chemical solution supply system according to an embodiment.

FIG. 2 is a schematic sectional view showing an example of a cleaning chamber which is a component of the single wafer spin cleaning apparatus according to the present embodiment.

FIG. 3 is a schematic diagram illustrating an example of a diluting solution supply unit that is a component of the chemical solution supply system.

FIG. 4 is a schematic view showing a liquid level adjusting unit.

FIG. 5 is a schematic diagram for explaining the operation principle of the liquid level adjusting means.

FIG. 6 is a characteristic diagram showing a relationship between a liquid level and a capacity of a cleaning liquid.

FIG. 7 is a schematic sectional view showing a liquid supply pump which is a component of the chemical liquid supply system.

FIG. 8 is another schematic sectional view showing a liquid supply pump which is a component of the chemical liquid supply system.

FIG. 9 is a schematic cross-sectional view showing the vicinity of a flow path of a liquid supply pump which is a component of the chemical liquid supply system.

FIG. 10 is a schematic sectional view showing the vicinity of a flow path when a liquid supply pump is driven.

FIG. 11 is a schematic diagram showing how a control system adjusts a discharge amount of a liquid supply pump.

FIG. 12 is a schematic diagram illustrating another example of a diluting solution supply unit that is a component of the chemical solution supply system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cleaning chamber 2 Chemical supply system 11 Wafer 12 Gate valve 13 Wafer holding pin 14 Wafer installation means 15 Cleaning liquid collision buffer 21 Dilute solution storage tank 22 Dilute solution supply device 23,123 Piping system 24,25 Discharge nozzle 26 Control system 31, 31a, 31b Liquid supply pump 32, 52, 102, 132 Connecting pipe 33, 40 Capillary 36 Mixing means 37 Chemical liquid supply control means 39 Mixing prevention mechanism 41 Flow path 42 Suction valve 43 Discharge valve 44, 45 Side wall 46 Piezoelectric vibrator 47 Drive Transmission means 48 Spring 49 Level gauge 121 Chemical storage tank 122 Chemical supply device 200 Weight scale

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Masahiro Miki 4-1-1 Hongo, Bunkyo-ku, Tokyo Ultra Clean Technology Development Laboratory F-term (reference) 3B201 AA03 AB03 AB34 AB42 BB05 BB24 BB92 BB93 BB96 CB01 CC12 CC13 CD42 CD43 3H071 AA01 BB01 CC33 CC34 DD04 DD12 DD13 DD31 DD72 3H075 AA09 BB04 CC34 CC35 DA05 DA09 DA22 DB02 4G068 AA02 AB15 AC05 AC16 AD04 AD21

Claims (14)

[Claims] 1. A chemical liquid supply system for mixing and diluting at least one chemical liquid with a solvent and supplying a final supply liquid adjusted to a predetermined chemical liquid concentration, wherein a high concentration of the chemical liquid is stored. A first storage tank, a first supply means for sucking out a predetermined amount of the chemical solution from the first storage tank and sending out, and forming a flow path of the solvent to which the first supply means is connected, A first piping system having a first discharge unit that discharges a diluted solution in which the chemical solution is mixed and diluted with the solvent and adjusted to a predetermined chemical solution concentration higher than the supply liquid; and the diluted solution is stored. A second storage tank, a second supply means for sucking out a predetermined amount of the diluting solution from the second storage tank and sending the diluted solution, and forming a flow path of the solvent to which the second supply means is connected. Before the diluted solution is further mixed and diluted with the solvent and the concentration is adjusted. And a second piping system having a second discharge unit for discharging the supply liquid, wherein a required amount of the chemical liquid is supplied to the solvent flowing through the first piping system by driving the first supply unit. The diluted solution is mixed to generate the diluted solution, the diluted solution is discharged from the first discharge unit and stored in the second storage tank, and a required amount of the diluted solution is driven by driving the second supply unit. A chemical liquid supply system, wherein a diluted solution is mixed with the solvent flowing in the second piping system to generate the supply liquid having a desired concentration, and the supply liquid is supplied from the second discharge unit. 2. A chemical liquid supply system for mixing and diluting at least one chemical liquid with a solvent and supplying a final supply liquid adjusted to a predetermined chemical liquid concentration, wherein a high concentration of the chemical liquid is stored. A storage tank, a first supply unit for sucking a predetermined amount of the chemical solution from the first storage tank and sending the solution, and mixing and diluting the chemical solution sent from the first supply unit with the solvent. A second storage tank in which a diluted solution adjusted to a predetermined chemical solution concentration higher than the supply liquid is stored, and a second pumping out and sucking out a predetermined amount of the diluted solution from the second storage tank. A supply system, and a piping system that forms a flow path of the solvent to which the second supply unit is connected, and discharges the supply liquid whose concentration is adjusted by further mixing and diluting the dilute solution with the solvent from an end. By driving the first and second supply means, A chemical liquid supply system, wherein the supply liquid having a predetermined concentration generated by performing stepwise dilution of the chemical liquid using the first and second storage tanks is supplied. 3. The method according to claim 1, further comprising: forming a flow path of the solvent to which the first supply unit is connected, and discharging the diluted solution mixed and diluted with the solvent to the second storage tank in the flow path. The chemical supply system according to claim 2, further comprising a piping system. 4. A flow path for the solvent is formed, and another piping system for discharging the solvent to the second storage tank is provided. The chemical solution is mixed and diluted with the solvent in the second storage tank. Producing said diluted solution.
3. The chemical solution supply system according to item 1. 5. The first and second supply means are provided with a flow path through which the dilute solution and the chemical solution pass, and suction is closed at an inlet of the flow path due to a rise in pressure of the dilute solution and the chemical solution. A valve is a liquid supply pump in which a discharge valve is provided at an outlet of the flow path, the discharge valve being closed by a decrease in pressure of the diluting solution and the chemical liquid, and at least a part of a liquid contact surface in the flow path has the chemical liquid. A dense member that is impermeable and highly resistant to corrosion, a part of the dense member is a movable wall, and a vibrator connected to the movable wall is provided. The movable member is driven by driving the vibrator. The chemical solution supply system according to any one of claims 1 to 4, wherein the wall is vibrated in a direction substantially orthogonal to the wall surface to periodically change the volume of the flow path. 6. A connection path for connecting each of the piping systems and each of the supply means, wherein each of the connection paths is directly connected to each of the piping systems, and the solvent of the chemical solution or the diluted solution is provided. The chemical solution supply system according to any one of claims 1 to 5, further comprising a thin tube member serving as a discharge portion to the liquid supply device. 7. The chemical liquid supply system according to claim 1, further comprising a control system for adjusting the amount of the supplied liquid and the concentration of the chemical liquid. 8. A first concentration measuring means provided in the first storage tank for measuring a storage amount of the chemical solution to calculate a chemical solution concentration of the diluted solution in the second storage tank, And a second concentration measuring means provided in the second storage tank and measuring a storage amount of the diluting solution to calculate a chemical concentration of the supply liquid. The chemical solution supply system according to the above section. 9. A first concentration measuring means provided in the first storage tank for measuring a storage amount of the chemical solution to calculate a chemical solution concentration of the diluted solution in the second storage tank; And a second concentration measuring means provided in the second storage tank and measuring a storage amount of the diluting solution to calculate a chemical concentration of the supply liquid, wherein the control system is provided by the first concentration measuring means. Referring to the calculated value of the chemical concentration of the diluted solution and the calculated value of the chemical concentration of the supply liquid by the second concentration measuring means, the second
8. The method according to claim 7, wherein the control unit controls the supply of the diluted solution by adjusting the discharge amount and the discharge speed of the diluted solution from the second supply unit to control the chemical concentration of the supply liquid to a target value. The chemical solution supply system according to the above. 10. The first and second concentration measuring means,
It has a pair of rod-shaped sensors made of a conductive member, and measures the electric capacity of the immersion part of the rod-shaped sensor in the chemical solution and the diluting solution and its time change, thereby obtaining a liquid of the chemical solution and the diluting solution. The chemical solution supply system according to claim 8, wherein the chemical solution supply system is a liquid level meter that calculates the chemical solution concentration by obtaining a surface height and a change speed thereof. 11. The first and second concentration measuring means,
The chemical solution supply system according to claim 8 or 9, wherein the weight solution is a weighing scale that measures the weight of the chemical solution and the diluted solution and changes thereof, and calculates the chemical solution concentration. 12. A substrate cleaning apparatus for supplying a cleaning liquid to an installed substrate and cleaning the substrate, comprising the chemical liquid supply system according to claim 1, wherein the supply liquid is used as the cleaning liquid. A substrate cleaning apparatus characterized by being used. 13. A chemical liquid supply method for mixing and diluting at least one chemical liquid with a solvent and supplying a final supply liquid adjusted to a predetermined chemical liquid concentration, wherein the first liquid supply means drives the liquid chemical. The first where was stored
Mixing and diluting a required amount of the chemical solution from the storage tank with the solvent flowing in the first piping system to generate a dilute solution adjusted to a predetermined chemical solution concentration higher than the supply liquid, Is stored in a second storage tank, and a required amount of the diluting solution is further mixed and diluted from the second storage tank with the solvent flowing in a second piping system by driving a second supply unit. And a chemical supply method for generating and supplying the supply liquid having a predetermined chemical concentration. 14. The first and second supply means are formed with a flow path through which the dilute solution and the chemical solution pass, and the suction is closed at an inlet of the flow path due to a rise in pressure of the dilute solution and the chemical solution. A valve is a liquid supply pump in which a discharge valve is provided at an outlet of the flow path, the discharge valve being closed by a decrease in pressure of the diluting solution and the chemical liquid, and at least a part of a liquid contact surface in the flow path has the chemical liquid. A dense member that is impermeable and highly resistant to corrosion, a part of the dense member is a movable wall, and a vibrator connected to the movable wall is provided. The movable member is driven by driving the vibrator. 14. The method according to claim 13, wherein the wall is vibrated in a direction substantially perpendicular to the wall surface to periodically change the volume of the channel.