JP4790995B2 - Slurry dilution device - Google Patents

Description

The present invention relates to a slurry dilution system for making a slurry solution supplied to the substrate polishing apparatus used in a semiconductor manufacturing device or the like, in particular, was diluted less slurry stock solution with an amount of pure water, the slurry diluted capable concentration accurately adjusted Relates to the device.

Conventionally, in mixing a plurality of types of liquids, mixing using a liquid mixing apparatus has been performed. Here, as an example of liquid mixing, a slurry dilution apparatus for mixing a slurry stock solution and pure water for producing a slurry solution supplied to a substrate polishing apparatus for polishing a substrate such as a semiconductor substrate will be described.

  Conventionally, in order to produce a slurry solution whose concentration is adjusted by diluting the slurry stock solution with pure water, for example, a predetermined amount of the slurry stock solution is supplied from the stock solution supply means into a cylindrical container having the same inner diameter in the vertical direction. Then, a predetermined amount of pure water is supplied from the pure water supply means into the container, and the slurry stock solution and pure water are mixed in the container to obtain a slurry solution having a predetermined concentration. At this time, the slurry stock solution and the pure water are measured by measuring the liquid level with a liquid level gauge attached to the wall surface of the container.

  However, in the above method, when the amount of pure water is large relative to the diluted slurry stock solution, the same inner diameter is used in the vertical direction. There is a problem that it is smaller than the change in the liquid level due to water, and it is difficult to accurately measure the amount of the slurry stock solution, and it is difficult to obtain a slurry solution whose concentration is adjusted accurately.

  Furthermore, as another method for preparing the slurry solution, there is a method in which the amount of the slurry stock solution and pure water is measured in advance, and the measured slurry stock solution and pure water are supplied into the container and mixed. Then, since the work of measuring the liquid volume of the slurry stock solution and the work of measuring the liquid volume of pure water are required in advance, the procedure for preparing the slurry solution becomes complicated, and the liquid volume of the slurry stock solution is measured. Since it is necessary to separately provide a device for measuring and a device for measuring the amount of pure water, there is a problem that the configuration of the device becomes complicated and the device becomes large.

  In addition, the conventional mixing method is to supply a small amount of slurry stock solution and a large amount of pure water into a container having the same inner diameter in the vertical direction, and stir and mix them with a stirrer or the like. There is also a problem that it takes time to uniformly mix the water with pure water.

The present invention has been made in view of the above points, and its purpose is to have a simple configuration, accurately measure the amount of each liquid to be mixed, and to make a highly accurate mixed liquid, An object of the present invention is to provide a slurry diluting device capable of uniformly mixing each liquid in a short time.

The invention described in claim 1 of the present application is a slurry diluting device for mixing a slurry stock solution and pure water for producing a slurry solution to be supplied to a substrate polishing apparatus for polishing a substrate such as a semiconductor substrate . A mixing tank comprising an upper tank and a lower tank, wherein the lower tank is integrally provided below the upper tank, an inner diameter thereof is smaller than an inner diameter of the upper tank, and an inside communicates with the upper tank; Slurry supply means for supplying a slurry stock solution to the preparation tank, pure water supply means for supplying pure water to the preparation tank, control means for controlling supply of the slurry stock solution and pure water to the preparation tank, and the upper part Upper tank liquid level detecting means comprising a capacitive liquid level sensor attached to the outer surface of the tank, and a capacitive liquid level attached to the outer surface of the lower tank A lower tank solution level detecting means including a bell sensor is installed in said upper tank, a slurry supply pipe slurry concentrate passes supplied from the slurry supply unit, the pure water supplied from the pure water supply means through A pure water supply pipe; a slurry supply pipe; and a merge pipe section where the discharge-side end of the pure water supply pipe merges, with a discharge port of the merge pipe section facing an inlet of the lower tank And the control means supplies the slurry stock solution to the lower tank by the slurry supply means, and when the lower tank liquid level detection means detects a predetermined liquid level, the slurry The supply of the stock solution is stopped, and pure water is supplied from the pure supply means to the lower tank, so that the slurry stock solution and pure water are mixed in the lower tank, and the slurry solution generated by the mixing is mixed with the lower solution. By overflowing the tank flows into the upper tank, when the upper tank liquid level detecting means detects a predetermined liquid level, in a slurry dilution apparatus characterized by stopping the supply of the pure water.

According to a second aspect of the present invention, in the slurry diluting device according to the first aspect, the bottom of the upper tank is inclined so that its height gradually decreases from the outer peripheral end toward the central opening. The inclined plate is attached, and an opening for discharging the mixed slurry solution is provided at the bottom of the lower tank .

According to the first aspect of the present invention, the preparation tank is composed of an upper tank having a large inner diameter and a lower tank having a small inner diameter, the slurry supply means supplies the slurry stock solution to the lower tank, and the lower tank liquid level detection means When the predetermined liquid level is detected, the supply of the slurry stock solution is stopped, and pure water is supplied from the pure supply means to the lower tank, so that the slurry stock solution and the pure water are mixed in the lower tank. Since the generated slurry solution overflows the lower tank and flows into the upper tank, when the upper tank liquid level detecting means detects a predetermined liquid level, the supply of the pure water is stopped. While different liquids are mixed and stirred in the lower tank, the liquid flows into the upper tank, and a slurry solution having a concentration adjusted with high accuracy can be made in a short time .

Further, since the inner diameter of the lower tank is small, even a small amount of the slurry stock solution supplied to the lower tank can be accurately measured by the lower tank liquid level detecting means, and the slurry solution obtained by diluting the small amount of slurry stock solution can also be used. Since it can be detected with high accuracy by the surface detection means, the concentration of the slurry solution can be adjusted with high accuracy with a simple configuration.

Furthermore, since both the upper tank liquid level detecting means and the lower tank liquid level detecting means are liquid level sensors, the liquid level in the container can be detected accurately. For this reason, the liquid amount of each liquid can be measured accurately and the liquid mixture of the density | concentration adjusted with high precision can be made. Further, since the liquid level sensor is attached to the outer surface of the tank, the attachment is simple and the maintenance becomes easy.

Furthermore, a slurry supply pipe through which the slurry stock solution supplied from the slurry supply means passes, a pure water supply pipe through which pure water supplied from the pure water supply means passes, and an end portion on the discharge side of the slurry supply pipe and the pure water supply pipe And a pipe member formed by disposing the discharge port of the merging pipe part toward the inlet of the lower tank, so that the liquid passing through the merging pipe part is contained in the lower tank. Then, the liquid is mixed efficiently, and finally the liquid is made pure water, so that the inside of the merging pipe section is cleaned, and the number of times of maintenance of the apparatus can be reduced.

  Further, since the slurry stock solution and the pure water pass through the junction pipe portion of the piping member, even if the solid matter contained in the slurry stock solution is deposited on the inner wall of the junction pipe portion, it is washed away by the pure water. Since this is effective, the number of times of maintenance of the apparatus can be reduced.

  According to the second aspect of the present invention, the slant plate is attached to the bottom of the upper tank so that the slurry solution in the upper tank does not remain and moves to the lower tank, and opens to the bottom of the lower tank. By providing the part, the slurry diluent in the preparation tank is surely discharged to the outside from the opening, so that the entire amount of the slurry solution in the preparation tank can be reliably transferred to the other after mixing. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an exploded perspective view of a slurry diluting apparatus 1 according to an embodiment of the present invention. FIG. 2 is a view showing the assembled slurry diluting apparatus 1, and FIG. FIG. 5B is a schematic side sectional view thereof. The slurry diluting device 1 is a device for producing a slurry solution such as silica (SiO 2) to be supplied to a substrate polishing device used in a semiconductor manufacturing device or the like. The slurry solution is mixed with pure water to produce a slurry solution having a desired concentration. Is.

  The slurry diluting apparatus 1 includes a preparation tank 10 that is a container for diluting the slurry stock solution therein, and the preparation tank 10 has an upper tank 11 having a large inner diameter dimension β and an inner diameter dimension α that communicates with the upper tank 11. It is composed of a small (β> α) lower tank 15. The blending tank 10 is installed in a slurry supply pipe 20 for supplying a raw slurry solution from a raw liquid storage tank (not shown), a pure water supply pipe 30 for supplying pure water from a pure water storage tank (not shown), and an upper tank 11. A piping member 40 through which the slurry stock solution and pure water pass, a lid member 50 attached to the opening of the upper tank 11, a liquid level sensor 60 attached to the wall surface of the lower tank 15, A liquid level sensor 70 attached to the wall surface of the upper tank 11 is provided. Hereinafter, the configuration of the slurry dilution apparatus 1 will be described in detail.

  The upper tank 10 and the lower tank 15 are containers for storing chemicals made of materials such as PVC (vinyl chloride resin), PFA (perfluoroalkyl vinyl ether resin), and glass. The upper tank 11 is provided with an opening 11a at its upper end, and a plurality of mounting holes 11b (four in the figure) for attaching the lid member 50 are provided around the opening 11a. As shown in FIG. 2, an inclined plate 13 is attached to the bottom portion 12 so as to be gradually lowered from the outer peripheral end portion toward the central opening portion 12a.

  On the other hand, the bottom 16 of the lower tank 15 is provided with an opening 16a, and a valve 18 is attached to the opening 16a. By opening the valve 18, the slurry solution diluted in the preparation tank 10 can be taken out through the opening 16 a. The valve 18 is a so-called surface-mounted valve, and the discharge port 18 a at the lower end thereof is engaged with an opening 81 provided in the upper part of the storage tank 80, and the preparation tank 10 is placed on the upper part of the storage tank 80. be able to.

  As described above, the inner diameter dimension α of the lower tank 15 is configured to be smaller than the inner diameter dimension β of the upper tank 11. And the lower tank 15 is equipped with the volume which can accommodate the slurry stock solution required for the slurry solution made at a time in the inside. Further, the volume of the upper tank 11 is larger than that of the lower tank 15. The total volume of the upper tank 11 and the lower tank 15 is configured to have a volume capable of accommodating a slurry solution made at a time therein.

  Next, a raw solution valve 22 is attached to the slurry supply pipe 20, and this raw solution valve 22 is connected to the valve bracket 23 on the lower surface side of the lid member 50 and the valve bracket 23 attached to the upper surface of the lid member 50. It is connected to the undiluted solution line 41 of the piping member 40 mentioned below via the made joint 24. Therefore, the slurry stock solution sucked from the stock solution tank is guided from the slurry supply pipe 20 through the stock solution valve 22 to the stock solution pipe 41 of the piping member 40. The stock solution valve 22 is a valve configured to open and close the flow path of the slurry stock solution corresponding to the atmospheric pressure in the preparation tank 10.

  The pure water supply pipe 30 is configured to be connected to a pure water pipe line 42 of a piping member 40 described below via a joint 32, a connection pipe 33, and a joint 34. Therefore, the pure water supplied from the pure water tank is guided to the pure water pipeline 42 through the pure water supply pipe 30 and the connection pipe 33. Further, a pure water valve 31 is provided in the middle of the pure water supply pipe 30, and pure water can be supplied and stopped by opening and closing the pure water valve 31.

  The piping member 40 is formed of a fluororesin such as PFA, and as shown in FIG. 3, is connected to the substantially straight stock solution pipe 41 connected to the slurry supply pipe 20 and the pure water supply pipe 30. And a pure water pipe 42 provided with a bent portion 42a bent in a substantially right angle direction, and the discharge side end of the stock solution pipe 41 and the discharge side end of the pure water pipe 42 merge at the junction 43. The merging conduit 44 is formed in a substantially straight line. The pure water pipe 42 is attached to the undiluted liquid pipe 41 and the merging pipe 44 linearly formed integrally therewith by a joint connection by welding at the merging portion 43. As shown in FIG. 2, when the piping member 40 is installed in the upper tank 11 of the preparation tank 10, the discharge port 45 at the lower end thereof opens toward the opening 12 a that is the opening of the lower tank 15, The slurry and pure water are formed in such a length and shape that can be supplied into the lower tank 15.

  The lid member 50 is a flat plate member made of a material such as PVC (vinyl chloride resin), PFA (perfluoroalkyl vinyl ether resin) or glass, and covers the lid member 50 by attaching it to the opening 11a of the preparation tank 10. Thus, it is formed in the shape substantially the same as the external shape of the opening part 11a. As shown in FIG. 1, the lid member 50 has a mounting hole 51 through which the shaft portion 23 a of the valve bracket 23 is inserted, and a mounting hole 52 through which the connection pipe 33 is inserted and attached. A mounting hole 54 to which a vacuum suction pipe 53 connected to a vacuum suction device (not shown) is attached is provided. A check valve 55 and a float switch 56 are also provided. Further, a plurality of attachment holes 57 (four in the figure) are provided in the outer peripheral portion of the lid member 50, and the lid member 50 is inserted into the attachment holes 57 and the attachment holes 11 b of the preparation tank 10. Is attached to the mixing tank 10 and closes the opening 11a in a sealed state.

  Next, the liquid level sensor 60 which is the lower tank liquid level detection means and the liquid level sensor 70 which is the upper tank liquid level detection means are both stored inside the lower tank 15 and the upper tank 11 from the outside. The liquid level can be detected, and a level sensor (liquid level sensor) is used here. As this level sensor, it is preferable to use a capacitance type level sensor. The capacitance type level sensor detects a change in electrical output as a change in capacitance of a capacitor when detecting the position of a liquid level or the like. Here, a case where a capacitance type level sensor is used will be described as an example. However, the liquid level sensor 60 and the liquid level sensor 70 are not limited to the capacitance level sensor, and a laser is applied to the liquid level. It is also possible to use an optical type that emits light, an ultrasonic type level sensor that emits ultrasonic waves, or the like.

  As shown in FIG. 2, the liquid level sensor 60 is attached to the outer surface 15 c of the lower tank 15 with the detection surface 61 facing the inside of the lower tank 15 of the preparation tank 10 by the sensor bracket 65. . FIG. 4 is a view showing the liquid level sensor 60 and the sensor bracket 65. FIG. 4 (a) is a view of these from the top, and FIG. 4 (b) is a view of the sensor bracket 65 from the side. It is a figure. As shown in FIG. 4, the liquid level sensor 60 has a rectangular substantially flat plate shape having a detection surface 61, and the detection surface 61 has a planar shape, so that the outer surface of the lower tank 15 that is curved as it is. Since it cannot be attached to 15c, one side surface 67 of the sensor bracket 65 is formed in a shape that matches the curvature of the outer surface 15c, and is attached to the outer surface 15c by this sensor bracket 65. As shown in FIG. 2B, the sensor bracket 65 is formed in a substantially U shape when viewed from the side, and is provided with a storage portion 66 for storing the detection surface 61 inside. Reference numeral 62 denotes a screw for attaching the liquid level sensor 60 to the sensor bracket 65.

  This liquid level sensor 60 is supplied by being attached to a position of the outer surface 15c of the lower tank 15 that matches the height at which the liquid level is located when the slurry stock solution is stored in the lower tank 15. When the amount of the slurry stock solution to be reached reaches a desired amount, the liquid level sensor 60 is configured to detect this. The sensor bracket 65 to which the liquid level sensor 60 is attached is fixed to the outer surface 15c of the lower tank 15 by adhesion or affixed with an adhesive tape or the like. When the amount of slurry solution to be diluted and its concentration are switched and used, the liquid level sensor 60 is provided on the outer surface 15 c of the lower tank 15 in accordance with the amount of the slurry stock solution supplied into the lower tank 15. For example, a guide rail or the like may be attached in a semi-fixed state so that the attachment position can be moved up and down.

  The undiluted liquid valve 22 is controlled to be opened and closed by an output signal of the liquid level sensor 60. When the liquid level in the lower tank 15 is detected by the liquid level sensor 60, the undiluted liquid valve 22 is detected by the detection signal. It is closed and the supply of the slurry stock solution is stopped.

  On the other hand, FIG. 5 is a view showing the liquid level sensor 70 and the sensor bracket 75. FIG. 5A is a view of these from the upper side, and FIG. 5B is a view showing only the sensor bracket 75 on the side. It is the figure seen from the direction. Similarly to the liquid level sensor 60, the liquid level sensor 70 is also attached to the outer surface 11 c of the upper tank 11 with the detection surface 71 facing the inside of the upper tank 11 by the sensor bracket 75. One side 77 of the sensor bracket 75 is formed to match the curvature of the outer surface 11 c of the upper tank 11. Further, as shown in FIG. 5B, the shape viewed from the side is formed in a substantially U shape, and a storage portion 76 for storing the detection surface 71 is provided inside.

  The liquid level sensor 70 is attached and supplied according to the height at which the liquid level is located when the diluted slurry solution is stored in the preparation tank 10 of the outer surface 11c of the upper tank 11. When the amount of pure water reaches a desired amount, the liquid level sensor 70 is configured to detect this. The sensor bracket 75 to which the liquid level sensor 70 is fixed with the screw 72 is fixed to the outer surface 11c of the upper tank 11 by adhesion, or is adhered and fixed with an adhesive tape or the like. When the amount and concentration of the slurry solution are switched, the liquid level sensor 70 can move the mounting position on the outer surface 11c of the upper tank 11 up and down in accordance with the amount of the slurry solution. As such, it may be attached in a semi-fixed state.

  The pure water valve 31 is controlled to be opened and closed by an output signal of the liquid level sensor 70. When the liquid level in the upper tank 11 is detected by the liquid level sensor 70, the pure water valve 31 is detected by the detection signal. 31 is closed and the supply of pure water is stopped.

  Although one liquid level sensor 60 and one liquid level sensor 70 are attached to the lower tank 15 and the upper tank 11, respectively, two or more of them can be attached.

  Next, a procedure for making a slurry solution using the slurry dilution apparatus 1 having the above-described configuration will be described. As shown in FIG. 2, the blending tank 10 is placed on the upper part of a storage tank 80 that stores the slurry solution, and the discharge port 18 a of the valve 18 is connected to the opening 81 of the storage tank 80. In this state, the valve 18 is closed. And the vacuum suction apparatus which is not shown in figure is operated, the gas in the preparation tank 10 is attracted | sucked, and the inside of the preparation tank 10 is made into a vacuum state. Here, when the gas in the preparation tank 10 is sucked to a certain level, the pressure applied to the stock solution valve 22 is changed to open the stock solution valve 22. The slurry stock solution is sucked from the stock solution tank, led to the stock solution pipeline 41 of the piping member 40 through the slurry supply pipe 20 and the stock solution valve 22, and from the stock solution pipeline 41 through the confluence pipeline 44 to the lower tank 15. It flows down inside. The slurry stock solution that has flowed down accumulates in the lower tank 15 and gradually rises in liquid level. When the liquid level reaches a preset level, the liquid level sensor 70 detects the liquid level, the stock solution valve 22 is closed, and the supply of the slurry stock solution is stopped.

  Subsequently, by opening the pure water valve 31, pure water is sucked from the pure water tank, and the pure water is guided to the merge pipe 44 through the pure water supply pipe 30, the pure water pipe 42 and the junction 43. Then, it flows down into the lower tank 15. The pure water flowing into the lower tank 15 is mixed and stirred in the lower tank 15 with the previously stored slurry stock solution, and this mixed slurry solution (diluted solution of the slurry stock solution with pure water) is stored in the lower tank 15. The liquid level rises and eventually overflows from the lower tank 15 and flows into the upper tank 11. When the liquid level in the upper tank 11 is detected by the liquid level sensor 70, the pure water valve 31 is closed and the supply of pure water is stopped. Thus, a slurry solution diluted to a desired concentration is made.

In the method of making the slurry solution described above, the amount of the slurry stock solution to be supplied is measured by detecting that the liquid level in the lower tank 15 has reached a predetermined height. Since the dimension α is formed to have an inner diameter dimension smaller than the inner diameter dimension β of the upper tank 11, a small amount of the slurry stock solution can be measured with high accuracy. Further, the slurry solution was diluted with pure water for a large amount, it can be accurately metered even in the upper tank 11 larger inner diameter β is. Therefore, the concentration of the slurry solution can be accurately adjusted to the target concentration.

  Further, the liquid level of the slurry stock solution accumulated in the lower tank 15 and the liquid level of the slurry solution accumulated in the upper tank 11 are detected using a capacitance type liquid level sensor 60 and a liquid level sensor 70. Therefore, the liquid level is accurately detected. In addition, by using the liquid level sensor 60 and the liquid level sensor 70, it is possible to configure the slurry diluting apparatus 1 having a metering function at a lower cost than the conventional diluting apparatus. Furthermore, since the liquid level sensor 60 and the liquid level sensor 70 are attached to the outer surface of the blending tank 10, the adjustment and maintenance thereof can be easily performed, and the slurry dilution apparatus 1 can be easily handled. In addition, if the liquid level sensor 60 and the liquid level sensor 70 are attached in a state in which their attachment heights can be changed, it is possible to easily cope with changes in the concentration and amount of slurry solution. Become.

  In addition, the portion of the merging pipeline 44 of the piping member 40 passes through the slurry stock solution supplied from the stock solution tank and also passes the pure water supplied from the pure water tank. Therefore, even if solids adhere to and accumulate on the inner wall of the slurry stock solution passing through the portion of the joining pipe 44, the deposit is periodically washed away by passing pure water. 44 can be prevented from being clogged, and the number of maintenance such as cleaning can be reduced.

  Moreover, since the mixing of the slurry stock solution and the pure water is performed so that the pure water is mixed and stirred in the slurry stock solution in the lower tank 15 having a small volume, both are mixed well and overflowed from the lower tank 15 in the mixed state. Since it flows into the upper tank 11, a high-quality slurry solution with a uniform concentration is produced without providing any special stirring means.

  As described above, when a slurry solution having a target concentration is produced in the preparation tank 10, the valve 18 is opened, and the slurry solution in the preparation tank 10 is naturally dropped into the storage tank 80 and transferred. In addition, since the valve | bulb 18 was attached to the lower end of the mixing tank 10, and it comprised so that an internal slurry solution might be transferred by natural fall, it can transfer without leaving the whole quantity of the slurry solution in the mixing tank 10. Moreover, since a facility such as a pump for transferring the slurry solution is not required, the facility can be made compact. Since the inclined plate 13 is attached in the mixing tank 10, the slurry solution in the upper tank 11 is completely discharged by the inclined plate 13, so that the entire amount of the slurry solution in the mixing tank 10 is stored in the storage tank 80. Can be moved.

  A necessary amount of slurry solution can be stored in the storage tank 80 by repeatedly performing a series of operations consisting of the above-described operation of making the slurry solution and transferring the slurry solution. Even when the repetitive operation is performed, it is not necessary to change the installation location of the preparation tank 10 or to transfer the slurry solution with a pump (to another location).

  In addition, the shape of the preparation tank 10 is not restricted to the shape described in the said embodiment. Further, the present invention relates to a liquid mixing apparatus that mixes a plurality of different types of liquids. The liquid is not limited to a slurry stock solution, and may be other liquids, or a slurry stock solution that is a liquid may be pure water that is a solvent. It is not restricted to the case of diluting, You may mix a liquid and another liquid. Further, the liquid to be mixed is not limited to two types, and three or more types may be mixed. For example, a plurality of types of liquids may be sequentially supplied to the lower tank 15 one by one, and one type of liquid such as pure water or a plurality of liquids may be sequentially supplied to the plurality of types of liquids one by one. Further, the number of the lower tanks 15 is not limited to one, and a plurality of lower tanks having smaller inner diameters may be provided.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. Note that any shape, structure, material, and method not directly described in the specification and drawings are within the scope of the technical idea of the present invention as long as the effects and effects of the present invention are exhibited.

It is a disassembled perspective view of the slurry dilution apparatus 1 which is one Embodiment of this invention. FIG. 2A is a diagram showing the slurry diluting device 1, in which FIG. 1A is a view of the slurry diluting device 1 as viewed from above, and FIG. 1B is a schematic sectional side view of the slurry diluting device 1. It is a figure which shows the piping member. The liquid level sensor 60 is a view of the liquid level sensor 60 and the sensor bracket 65 as viewed from the upper side, and FIG. 5B is a side view of the sensor bracket 65. It is the figure seen from. The liquid level sensor 70 is a view of the liquid level sensor 70 and the sensor bracket 75 as viewed from the upper side, and FIG. 5B is a side view of the sensor bracket 75. It is the figure seen from.

DESCRIPTION OF SYMBOLS 1 Slurry dilution apparatus 10 Preparation tank 11 Upper tank 12 Bottom part 13 Inclined plate 15 Lower tank 16 Bottom part 18 Valve 20 Slurry supply pipe 22 Stock solution valve 23 Valve bracket 30 Pure water supply pipe 31 Pure water valve 40 Piping member 41 Stock solution pipe line 42 Pure Water pipe 44 Merge pipe 45 Discharge port 50 Lid member 53 Vacuum suction pipe 60 Liquid level sensor 61 Detection surface 65 Sensor bracket 70 Liquid level sensor 71 Detection surface 75 Sensor bracket 80 Storage tank

Claims (2)

A slurry diluting device for mixing a slurry stock solution and pure water for producing a slurry solution to be supplied to a substrate polishing apparatus for polishing a substrate such as a semiconductor substrate,
A cylindrical upper tank and a lower tank, wherein the lower tank is integrally provided below the upper tank, the inner diameter thereof is smaller than the inner diameter of the upper tank, and the interior communicates with the upper tank A tank,
Slurry supply means for supplying a slurry stock solution to the preparation tank;
Pure water supply means for supplying pure water to the preparation tank;
Control means for controlling the supply of the slurry stock solution and pure water to the blending tank;
Upper tank liquid level detecting means comprising a capacitive liquid level sensor attached to the outer surface of the upper tank, and lower tank comprising a capacitive liquid level sensor attached to the outer surface of the lower tank Liquid level detection means;
A slurry supply pipe installed in the upper tank and through which a slurry stock solution supplied from the slurry supply means passes, a pure water supply pipe through which pure water supplied from the pure water supply means passes, the slurry supply pipe, and the A pipe member formed by disposing an end portion on the discharge side of the pure water supply pipe to join, and a discharge port of the join pipe portion facing the inlet of the lower tank;
With
The control means includes
When the slurry supply means supplies the slurry stock solution to the lower tank, and the lower tank liquid level detection means detects a predetermined liquid level, the supply of the slurry stock solution is stopped, and the pure supply means supplies pure water to the lower tank. By supplying water, the slurry stock solution and pure water are mixed in the lower tank, and the slurry solution generated by the mixing overflows the lower tank and flows into the upper tank, whereby the upper tank solution A slurry diluting device characterized in that when the surface detecting means detects a predetermined liquid level, the supply of the pure water is stopped. In the slurry dilution apparatus according to claim 1,
An inclined plate is attached to the bottom of the upper tank so that its height gradually decreases from the outer peripheral end toward the central opening,
A slurry diluting device, wherein an opening for discharging the mixed slurry solution is provided at the bottom of the lower tank.

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