EP1318306B1 - Device for dispensing a liquid - Google Patents

Description

The invention relates to a dispensing device for a fluid according to the The preamble of independent claim 1 and the use of a such dispenser.

In many industrial processes, for example in semiconductor and chip production, there is a need to transfer fluids in a controlled manner To dispense nozzles or similar devices. As an example, be here chemical-mechanical polishing processes (CMP, chemical-mechanical polishing) called, as used in the semiconductor industry. In such Processes is a suspension commonly referred to as slurry typically very fine solid particles and one liquid at a time applied rotating wafer and serves there for polishing or lapping the very fine semiconductor structures. Another example is the application of Photoresist on the wafer. Another example concerns the pumping of Wastewater. A corresponding device is for example in the US 6,241,485 B1.

A suitable and known from the prior art Dispensing device is illustrated in Fig. 1. The dispensing device 1 ' comprises a reservoir 2 'which communicates with the fluid, e.g. B. slurry, is filled. Of the Reservoir 2 'has an outlet 4' to which a pressure line 5 ' connected via a recirculation pump R 'up to a Input 6 'extends to the reservoir 2'. Downstream of Recirculation pump R 'are a plurality of removal points 7' in the pressure line 5 ' provided that to nozzles or other - usually as a tool designated - equipments lead, with which the fluid on the wafers is applied. Each removal point 7 'is provided with a valve 8' to to open or close the flow connection to the respective apparatus closure. Are all sampling points 7 'closed, then causes the Recirculation pump R 'a mere circulation of the fluid.

The desired pressure with which the fluid through the pressure line 5 'and the open sampling points 7 'promoted to the apparatus and there can be provided by pressurizing the fluid in the Generate reservoir 2 '. For this purpose, an inlet to the reservoir 2 ' 10 'is provided, through which a pressure regulating valve 11' via a pressure medium in the reservoir can be introduced, as symbolically by the arrow G. is shown. As a pressure medium is usually a gas, for. Nitrogen, used, with the in the reservoir 2 ', an overpressure of, for example 0.5 bar is maintained.

However, such a device has disadvantages. To the overpressure in the To generate reservoir 2 ', this must be configured gas-tight, which equipment is quite complex. Moreover, it is not easy to fill new fluid in the reservoir 2 'when the level to becomes low. Also, a change in the pressure in the reservoir 2 'and thus a change in the delivery pressure cumbersome and time-consuming. Further it is possible that the pressure medium (gas) penetrates into the fluid or in the fluid goes into solution, resulting in undesirable changes in the Composition of the fluid can result. Another problem can be added Suspensions such. As slurry occur, or fluids that are too Separations or clumping tend because of the Recirculation pump R 'caused circulation is usually too low to in the reservoir 2 'sufficient for a continuous mixing To ensure fluid movement. Therefore, often additional measures necessary to ensure adequate movement or mixing of the fluid in the reservoir 2 'permanently secure.

Based on this prior art, it is therefore an object of Invention to provide a fluid dispensing device, which the does not have mentioned disadvantages. The dispenser should be in easier Sufficient mixing of the fluid and its provision allow in a pressure line.

The task solving dispensing device is characterized by the features of independent claim 1.

According to the invention, therefore, a dispensing device for a fluid proposed with a reservoir for the fluid, which has an outlet having, which is connectable to a pressure line for the fluid, and with a rotary pump having a rotor for conveying the fluid into the Having pressure line, wherein the rotor for mixing the fluid is arranged directly in the outlet of the reservoir, wherein the rotor in a Rotor housing is provided, which is part of the wall of the reservoir forms.

The rotary pump thus fulfills two functions: First, it promotes that Fluid in the pressure line (pumping function), and on the other ensures the Arrangement of the rotor directly in the outlet of the reservoir a good and constant mixing of the fluid in the reservoir (Stirring function). This can be a separation or settling of particles in Suspensions, clumping or phase separation in the fluid be effectively prevented.

For the best possible mixing, it is advantageous if the Rotary pump has an inlet, the opening at least thirty Percent, in particular at least fifty percent of the diameter of the Rotor is.

Preferably, a control unit is provided for the rotary pump, which the delivery pressure of the rotary pump on the speed of the rotor established. Is the rotary pump in a work area with a operated low efficiency, there is a one-to-one for a given fluid Relationship between the speed of the rotor and the Pressure at the outlet of the pump. This has the great advantage that the pressure, with which the fluid is provided, in a simple manner and in a very short time Time, can be set or changed. An elaborate one Pressurization of the fluid in the reservoir is thus no longer necessary.

The stirring function of the rotor can be positively influenced when the rotor is designed and arranged so that it at least partially in the Inlet tank extends.

Preferably, the rotor comprises a plurality of wings extending in the Extend reservoir into it. This is especially possible Realize that the wings compared to known rotary pumps are oversized, so are significantly larger. The wings are thus used in addition to the pressure generation as stirring elements, which the fluid in the Keep the storage container in motion.

It is also advantageous if the rotary pump has a stator for driving of the rotor, wherein the rotor with respect to the stator without contact is magnetically stored. By this measure, no seals are on Shaft bearings necessary and the risk of damage such Seals, for example by abrasive particles, is avoided.

Particularly preferably, the rotary pump is a bearingless motor is designed and the rotor as integral rotor, because this is a very compact and space-saving design represents.

To the mixing and / or homogenization of the fluid in Still to improve reservoir, it may be advantageous to guide elements in to provide the reservoir.

In a preferred use, the invention serves Dispensing device for dispensing suspensions, in particular of Slurry, especially in a CMP process, or for delivering photoresist.

Further preferred uses of the inventive Dispensing device are determining the viscosity of a liquid as well the verification of properties of a fluid, in particular the Verification of the mixing ratio in a fluid resulting from composed of several components.

Further advantageous measures result from the dependent Claims.

Fig. 1:

Eine schematische Darstellung einer bekannten Abgabevorrichtung (Stand der Technik),

Fig. 2:

eine schematische Darstellung eines Ausführungsbeispiels einer erfindungsgemässen Abgabevorrichtung,

Fig. 3:

eine Variante für einen Vorratsbehälter, und

Fig. 4:

eine schematische Darstellung eines weiteren Ausführungsbeispiels einer erfindungsgemässen Abgabevorrichtung.

In the following the invention will be explained in more detail by means of embodiments and with reference to the drawing. In the schematic drawing show:

Fig. 1:

A schematic representation of a known dispensing device (prior art),

Fig. 2:

a schematic representation of an embodiment of an inventive dispensing device,

3:

a variant for a reservoir, and

4:

a schematic representation of another embodiment of an inventive dispensing device.

Fig. 1 shows a dispensing device 1 ', which represents prior art and has already been explained at the beginning.

Fig. 2 shows a schematic representation of an embodiment of a inventive dispensing device, the total with the Reference numeral 1 is designated. The dispensing device 1 comprises a Reservoir 2 for a fluid F having an output 4. In the exit 4, a rotary pump 3 is provided with a rotor 31, here as Centrifugal pump is formed. The outlet 41 of the rotary pump 3 is connected to a pressure line 5 extending from this outlet 41 of the Rotary pump 3 via a pressure reducing valve 9 to an input 6 of the Reservoir 2 extends. The pressure line 5 faces upstream of the Pressure Reducing Valve 9 at least one - here, for example, three - Entnahmestellen 7, each of which via a line 71 with a Apparatus T for dispensing the fluid F, e.g. As a nozzle, or a tool connected is. In each line 71, a valve 8 is provided, with which the flow connection between the sampling point 7 and the tool T can be opened or closed separately.

The outlet 4 is arranged at the bottom of the storage container 2. The opening the output 4 - which means its diameter - is identical to the Opening B of the inlet 30 of the rotary pump 3. This opening B is greater than half the diameter of the rotor 31.

The following is an example of a particularly important for practice Use, namely, that the inventive Dispensing device 1 in a CMP process (CMP: chemical-mechanical polishing) is used in the semiconductor industry. In these processes is called a slurry suspension of fine solid particles in a liquid applied to a rotating wafer and serves there for Lapping or polishing the very fine semiconductor structures. The fluid F is in In this example, the suspension referred to as slurry. The apparatus or Tools T each include a nozzle or other means with which the fluid F can be applied to the wafer.

With rotary pumps, which are also referred to as centrifugal pumps, are all those pumping devices are meant which include a rotor 31 and a Impeller, by the rotation of a momentum transfer to the promoting fluid takes place. The term rotary pump includes in particular Centrifugal pumps, axial and side channel pumps. typically, With a rotary pump, the inlet and the outlet are more constant Flow connection. For example, there are no valves between Pump inlet and outlet 41 is provided.

According to the invention, the rotor 31 is for mixing the fluid F arranged directly in the outlet of the reservoir 2. In this Embodiment protrudes the rotor 31 for mixing of the fluid F. at least partially into the reservoir 2 inside. Thus, the serves Rotary pump 3 not only the pumping of the fluid F, but also as Agitator, which mixes the fluid F in the reservoir 2. To For this purpose, the rotor 31 has a plurality of blades 311, which clearly are designed larger than comparable with known rotary pumps Dimensioning. As shown in FIG. 2 and FIG. 3, the wings are sufficient 311 in the reservoir 2 into and and provide here (during rotation of the Rotor 3) for a circulation of the fluid as indicated by the arrows Z. is.

The representation of the wings 311 in Fig. 2 and Fig. 3 is of course only exemplary to understand. The wings can still further approaches or larger areas or other suitable means to positively affect the stirring function influence.

The rotor 31 is arranged in a rotor housing 312, which is a part of the Wall of the reservoir 2 forms. The rotor housing 312 may be integral part of the reservoir 2 or as a separate part be attached to this.

The rotatipon pump 3 further includes a stator 32 having a Stator winding 322 to electrically drive the rotor 31. Furthermore, a Control unit 12 is provided, which controls the rotary pump 3 and regulates. The stator 32 surrounds the rotor housing 312. Preferably, the Stator 32 designed as a stator of a so-called temple motor. The means (see Fig. 2 and Fig. 3), the stator 32 has several by a Conclusion associated stator teeth, each stator tooth L-shaped is formed with a shorter and a longer leg. The longer one Leg extends in each case parallel to the axis of rotation of the rotor and the shorter leg extends radially inwardly toward the axis of rotation. The longer legs carry the stator winding 322nd

In particular for those fluids containing solid particles or the are highly pure, the rotary pump 3 preferably has a complete magnetically mounted rotor 31, that is, the rotor 31 is with respect to the Stators 32 non-contact magnetically mounted. The absence mechanical bearing for the rotor 31 has several advantages. That's how it works Problem avoided that abrasive particles damage mechanical bearings can. Furthermore, there is no risk of contamination of the fluid Lubricant or bearing wear. Also sealing problems are avoided.

Apparativ particularly simple and energetically favorable it is, if the rotor 31 is permanently magnetic. For this purpose, the rotor 31 comprises a Permanent magnet, for example, a permanent magnetic ring 313rd This ring 313 is disposed around a central bore 314 which along the desired axis of rotation of the rotor 31 therethrough extends. The magnetization of the ring 313 is indicated by the arrows (without Reference numeral) indicated in its interior.

A particularly preferred rotary pump z. In EP-A-0 819 330 or US-A-6,100,618. This rotary pump has a So-called integral rotor and is designed as a bearingless engine. With The term integral rotor is meant that the pump rotor and the Rotor of the motor driving the pump are identical. The rotor 31 acts both as a rotor of the motor drive and as the rotor of the Pump. By the term bearingless engine is meant that the rotor is stored completely magnetic, with no separate magnetic bearing are provided. The stator 32 is both stator of the electric drive as also stator of magnetic bearing. This includes the stator winding 322 a drive winding of the pole pair number p and a control winding of Pole pair number p ± 1. This makes it possible to both drive the rotor 31 and also to store completely contact-free magnetically in the stator. In terms of Further details of such a rotary pump is here on the already referenced documents.

During operation generated by the control unit 12 generates Stator winding 322 is a rotary drive field that provides torque to the rotor 31 causes and this set in rotation. Furthermore, the generated Control winding of the stator winding 322 a magnetic control panel, with in which the position of the rotor 31 with respect to the stator 32 is controllable.

By the rotation of the rotor 31, the fluid F through the inlet 30 of the Rotary pump 3 sucked and through the outlet 41 in the pressure line. 5 promoted, where the fluid under the delivery pressure, for example, 0.5 bar to one bar, ready. A small portion of the fluid F flows through the bore 314 (as the double arrow on the lower end of the bore as shown 314 in Figs. 2 and 3 indicates) and thus ensures that the rotor 31 Relieved with respect to the axial thrust.

Depending on which or which of the valves 8 is or are open, the fluid F passes from the pressure line 5 through the lines 71 to the individual tools T. The remainder of the fluid F, which is not delivered to the tools T. is, passes through the pressure reducing valve 9 and the input 6 back into the Reservoir 2, whereby a recirculation of the fluid F and thus a Mixing in the reservoir 2 is realized.

In addition to this pumping function causes the rotary pump 3 also directly a mixing of the fluid F in the reservoir 2, because in the Storage tank 2 projecting wings 311 act as stirring tools and mix the fluid 2 in the reservoir.

As in this embodiment, the inventive Dispensing device 1 (Fig. 2) in contrast to known Dispensing devices (Fig. 1), the delivery pressure with the rotary pump. 3 is generated and not by pressurizing the fluid with a Gas G, results in a much simpler construction. In addition, the must Reservoir 2 is not designed to be gas-tight, which is a simpler Refilling possible. In addition, there is no danger that as Pressure medium serving gas G, the fluid F contaminated in the reservoir 2.

Most preferably, the control unit 12, the delivery pressure of Rotary pump 3 via the rotational speed of the rotor 31 a, which is hereafter is explained.

In European Patent Application EP-A-1284369 of the same Applicant, it is proposed a rotary pump with a Efficiency to operate, which is significantly smaller than the maximum Efficiency of the rotary pump, for example, the highest 20 percent of maximum efficiency.

The term efficiency is the hydraulic efficiency of Rotation pump meant, that is the ratio of hydraulic Performance of the pump and mechanical power for the pump Drive of the rotor (without possibly existing friction losses in Storage or similar).

In European Patent Application EP-A-1284369 becomes explains that for such operating ranges of the rotary pump 3, in which the efficiency is well below the maximum efficiency, one-to-one Relationship between the speed of the pump rotor and the delivery pressure (delivery) and also between the speed and the Volume flow (flow) exists. In these operating areas is the Delivery pressure approximately proportional to the square of the speed of the Rotor. This opens up the possibility of conveying pressure directly and without adjust additional pressure measurement on the speed of the rotor 31 and to regulate.

The exact mathematical relationship between the delivery pressure and the speed, which of course also depends on the properties of the fluid F depends, does not need to be known. It is only essential that this Connection for those operating areas in which the rotary pump 3 working with a very small efficiency is one-unique. It will For example, pre-calibration measurements are made to the pressure-speed curve to investigate. This curve can then be called mathematical Function, eg. As a polynomial approximation, or as electronic Look-up table in a memory of the control unit 12 be filed. During operation of the rotary pump 3 is then for the desired delivery pressure the associated speed in the lookup table checked. By setting the appropriate speed can then the desired delivery pressure can be realized.

The one-to-one relationship between speed and delivery pressure or of course also depends on the speed between the flow and volume promoting fluid F, in particular from its viscosity. In the already cited European application EP-A-1284369 therefore becomes proposed the one-to-one context in Very low efficiency operating ranges exist for determining the viscosity or the dynamic viscosity of the fluid to use. In this regard, the explanations in this European Referenced patent application. In the same way, the same Inventive dispensing device 1 can be used to Properties of the fluid F, such as its viscosity or else determine its density or other quantities derived therefrom monitor. Thus, the possibility opens up with the inventive Dispensing device 1 additionally a quality control of the fluid online or to perform inline.

The determination of the viscosity of the fluid F is based on the motor current, with which the rotation of the rotor 31 is driven. The motor current is directly a measure of the torque at which the rotor 31 is driven becomes. In particular, in the case of the preferred embodiment of Rotary pump as a bearingless motor is due to the magnetic Rotor bearing no mechanical bearing friction present, so the torque at which the rotor is driven, in very good Approximation coincides with the torque transmitted to the fluid.

Due to the very low efficiency with which the Rotation pump 1 operated in the operating condition described here becomes, is virtually all the torque and thus the mechanical Power that transmits the impeller or the rotor 31 to the fluid, in Fluid friction losses converted. Thus, the torque of the Rotor 31 directly measures the viscosity, more specifically the dynamic Viscosity of the fluid, because the mechanical power of the rotor 31 is almost completely converted into friction losses of the fluid.

As already mentioned, the torque corresponding to the rotor on the Liquid transfers, essentially, that is, except for mechanical Frictional losses, the driving torque with which the rotor is driven becomes. This is especially true for magnetically mounted rotors. The Drive torque in turn is given by the motor current, which drives the rotor. With the motor current is doing as the armature current denoted torque-forming portion of the current in the electrical Drive meant. Especially in field-oriented three-phase motors and Also in DC motors, the armature current is a very good measure of the Torque with which the rotor is driven.

Thus, in the operating range in which the rotary pump 3 only with a fraction of their maximum efficiency works, a direct one Relationship between the motor current with which the pump is driven is, and the viscosity of the fluid. By measuring the motor current Thus, the dynamic viscosity of the fluid to be delivered in a simple Way and be determined online.

In a similar way, other properties of the Fluids, for example, its density or the mixing ratio of two Determine components of the fluid F, when the rotary pump 3 in such Operating conditions is operated in which they have a very low Efficiency has.

Especially with regard to quality control or the determination of Parameters of the fluid F, it may be advantageous if at the Rotary pump 3, for example, outside the rotor housing 312 a Temperature sensor 315 (see FIG. 3) is provided, with which the Temperature of the fluid F is detected.

In such operating areas where the rotary pump 3 with only one Fraction of their maximum efficiency works, so can the Delivery pressure, under which the fluid F provided in the pressure line 5 is, from the control unit 12 directly on the rotational speed of the rotor 31st be set and regulated. Thus, can be an extremely fast realize electrical or electronic adjustment of the delivery pressure. Of the Delivery pressure is, for example, at time intervals of less than 100 Adjustable in milliseconds.

Fig. 4 illustrates another embodiment, which especially suitable for those uses where the viscosity of the fluid or other of its properties. in the The following is based only on the differences from the embodiment Fig. 2 received. The reference numerals have the already introduced Importance.

In this embodiment, means for controlling the level of the Reservoir 2 is provided. These means comprise a tank 13 a Connecting line 14, which the tank 13 with the reservoir. 2 connects, and a constant volume of gas 15, which in the reservoir. 2 is provided. Of course, this gas volume 15 can also be zero. purpose this means 13, 14, 15 is to the level in the reservoir 2 to constant hold. The tank 13 has a variable level, it can also be refilled become. If now by means of the rotary pump 3 from the reservoir. 2 Fluid F is removed, then flows from the tank 13 through the Connecting line 14 fluid after. In this way, a constant Adjust level FS in storage tank 2.

The level control in the reservoir 2 is particularly advantageous then if with the inventive dispensing device 1, the viscosity or other properties of the fluid F are to be determined or monitored. Due to the constant level FS in the reservoir 2 is namely ensures that always the same amount of fluid F or liquid (ie the same amount) is applied in the reservoir 2 with stirring power. This stirring power is therefore a particularly good measure of the specific fluid friction and thus provides an accurate measure of the Viscosity. This is a much more accurate determination of the viscosity or other properties of the fluid.

Furthermore, it is possible - as indicated in Fig. 4 - that the Reservoir 2 with two-example different components as liquids and / or gases is fed, namely with a first Component from the tank 13 through the connecting line 14 in the Reservoir flows in, and with a second component through a another line 16 flows from a further, not shown tank.

The reservoir 2 then serves as a mixing container, in which the two Components are mixed to the fluid. In the same way as explained for the viscosity, can then with the inventive dispensing device 1, the mixing ratio of the two Components are monitored or checked.

Furthermore, Fig. 4 shows a variant of the embodiment and the Arrangement of the rotor 31. Here, the rotor 31 is configured and arranged that its wings 311 not into the reservoir 2 into it pass. The opening B and the diameter B of the inlet 30 is here too, more than fifty percent of the diameter of the rotor 31, around one to achieve good mixing.

Fig. 3 shows a variant of the reservoir 2. The reference numerals have the same meaning as explained with reference to FIG. At this Variant are the rotor housing 312 at the bottom of the reservoir 2 and the wings 311 slightly modified. In addition, in the storage container 2 static guide elements 21 are provided. These cause that of the Rotary pump 3 generated fluid flows further upwards (as shown in FIG. 3) are directed, as the arrows with the reference Z indicate. Especially with larger ones Storage containers 2 can be ensured by such a measure be that the constant mixing of the fluid F the entire Reservoir 2 includes and not locally to the vicinity of the rotor. 3 remains limited.

The dispensing device 1 according to the invention is particularly suitable for such Fluids F, which lead to clumping, phase separations, Precipitates or settling of particles tend, for example Suspensions, especially slurry solutions. By the recirculation and the Stirring action generated directly by the rotor 31 remains in the reservoir 2 fluid F in motion, so that a continuous mixing takes place.

Of course, the inventive dispensing device 1 is not on here described application, namely the promotion of a slurry suspension or limited CMP processes. It is also suitable among other things generally for the conveyance of suspensions, emulsions, paints, Foods (eg juices or concentrates).

A special advantage is the combination of pumping function and Stirring function, the delivery pressure in a very simple manner and extremely can be quickly adjusted and controlled electronically.

Claims (14)

1. A dispensing apparatus for a fluid having a supply tank (2) for the fluid which has an outlet (4) which can be connected to a pressure line (5) for the fluid (F), and having a rotary pump (3) which has a rotor (31) for conveying the fluid (F) into the pressure line, characterised in that the rotor (31) for mixing the fluid (F) is arranged directly in the outlet (4) of the supply tank (2), wherein the rotor (3) is provided in a rotor housing (312) which forms a part of the wall of the dispensing tank (2).
2. A dispensing apparatus in accordance with claim 1, in which the rotary pump (3) has an inlet (30) whose opening (B) amounts to at least thirty percent, in particular at least fifty percent, of the diameter of the rotor (31).
3. A dispensing apparatus in accordance with claim 1 or claim 2, having a control unit (12) for the rotary pump (3) which adjusts the forwarding pressure of the rotary pump (3) via the speed of the rotor (31).
4. A dispensing apparatus in accordance with any one of the preceding claims, wherein the rotor (31) is designed and arranged such that it extends at least in part into the supply tank (2).
5. A dispensing apparatus in accordance with any one of the preceding claims, wherein the rotor (31) includes a plurality of vanes (311) which extend into the supply tank (2).
6. A dispensing apparatus in accordance with any one of the preceding claims, wherein the rotary pump (3) has a stator (32) to drive the rotor (31), with the rotor (31) being magnetically mounted in a contact-free manner with respect to the stator (32).
7. A dispensing apparatus in accordance with any one of the preceding claims, wherein the rotary pump (3) is designed as a bearing-free motor and the rotor (31) as an integral rotor.
8. A dispensing apparatus in accordance with any one of the preceding claims, wherein the rotor (31) is permanently magnetic.
9. A dispensing apparatus in accordance with any one of the preceding claims, wherein guide elements (21) are provided in the supply tank (2).
10. A dispensing apparatus in accordance with any one of the preceding claims, having a pressure line (5) which extends from an outlet (41) of the rotary pump (3) up to an inlet (6) of the supply tank (2) and has at least one removal point (7).
11. A dispensing apparatus in accordance with any one of the preceding claims, having means (13, 14, 15) for regulating the level of the supply tank.
12. Use of a dispensing apparatus in accordance with any one of the preceding claims for the dispensing of suspensions, in particular of slurry, especially in a CMP process, or for the dispensing of photoresist.
13. Use of a dispensing apparatus in accordance with any one of claims 1-11 for the determination of the viscosity of a liquid.
14. Use of a dispensing apparatus in accordance with any one of claims 1-11 for the checking of properties of a fluid, in particular for the checking of a mix ratio.

Images