JP2000218107A - Filter and grinding liquid supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To replace a filter smoothly and surely and to catch solid particles contained in fluid continuously and surely with the replacement omitted by installing a valve device which connects one of filter units selectively to fluid piping and simultaneously another one to a regeneration piping. SOLUTION: In usual operation, one of filter units 30a, 30b is connected to a grinding liquid line 32 to filter out solids from a grinding liquid, and the other is connected to a regeneration line 34 to implement a cleaning/regeneration process. When the catching amount of the filter unit connected to the line 32 reaches a prescribed value, it is connected to the line 34 to be changed over to the filter unit which was cleaned/regenerated. The changeover is done by actuating a rotary actuator 50 and rotating a movable plate 44 by 180 degree. Accordingly, the grinding liquid can be supplied continuously and automatically without stopping the line 32 and without removing the filter units 30a, 30b from joints.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter device for removing solid impurities in a pipe through which a fluid flows, and more particularly to a filter device for use in a polishing liquid supply line for a chemical mechanical polishing apparatus (CMP) for semiconductor substrates. The present invention relates to a suitable filter device and a polishing liquid supply device provided with such a filter device.

[0002]

2. Description of the Related Art In recent years, as the degree of integration of semiconductor devices has increased, circuit wiring has become finer, and the distance between wirings has become smaller. Accordingly, when a circuit is formed by optical lithography or the like, the depth of focus becomes shallow, so that a higher flatness of the imaging surface of the stepper is required.

As means for flattening the surface of a semiconductor wafer, for example, as shown in FIG. 15, a polishing table 4 having a polishing surface formed by attaching a polishing cloth 2 to the surface, and a semiconductor wafer or the like to be polished are provided. A substrate gripping device (top ring) 6 for gripping the substrate W, and while supplying the polishing liquid Q between the polishing surface and the surface to be polished of the substrate W through the polishing liquid supply pipe 8, the substrate W In some cases, polishing is performed by relatively sliding the polishing surface and the substrate W while pressing the substrate against the polishing surface with a predetermined pressure. Such an apparatus not only performs mechanical polishing using a polishing liquid as a polishing liquid, but also performs polishing involving a chemical action using an alkaline or acidic polishing liquid as the case may be.

[0004] In the polishing liquid supply system of such a polishing apparatus, there is a case where abrasive particles are aggregated in the middle of a pipe to generate particles. When the particles are supplied to the surface to be polished, scratches called scratches are formed on the surface to be polished. Will be generated. Therefore, it is conceivable to attach a filter for capturing particles of a certain size or more in the fluid to the piping path. As shown in FIG. 16, such a filter is branched and the filters fa and fb are respectively branched through joints (not shown) so that the filter can be replaced without stopping the line when a predetermined processing time has elapsed. Will be attached.

[0005]

However, when a filter is attached to a pipe through a joint as described above, it is necessary to attach and detach bolts and nuts at the time of replacement, and the abrasive liquid is scattered. Poor workability. Further, among the branched pipes, there arises such a problem that the abrasive grains in the polishing liquid remaining in the unused pipes aggregate and generate particles.

SUMMARY OF THE INVENTION In view of the above problems, the present invention enables a smooth and reliable replacement of a filter and further eliminates the need for replacement and continuously removes solid matter contained in a fluid such as abrasive fluid in a pipe. An object of the present invention is to provide a filter device that reliably captures particles, supplies a high-quality fluid, and enables stable operation without clogging.

It is a further object of the present invention to provide a polishing liquid supply device which is provided with such a filter device so that solid particles contained in the polishing liquid can be removed smoothly.

[0008]

That is, the present invention provides a fluid pipe through which a handling fluid such as an abrasive fluid flows, and a filter device connectable to a regeneration pipe through which a filter regeneration fluid flows. A filter, comprising: a filter unit; and a valve device for selectively connecting one of the filter units to the fluid pipe and connecting one of the other filter units to the regeneration pipe. apparatus.

In this filter device, while one filter unit is being used for filtration in the fluid pipe, the other filter unit is subjected to regeneration processing, that is, clogging removal processing, in the regeneration pipe. When it is determined that clogging has occurred, both filter units are exchanged between the fluid pipe and the regeneration pipe for use.

In this filter device, the filter regeneration pipe has a plurality of regeneration pipes through which different filter regeneration fluids flow, and the valve device sequentially switches the filter units from the fluid pipe to the different regeneration pipes. It can also be switchable to connect sequentially to the tubing and then connect again to the fluid tubing.

In this way, the filter unit to be regenerated is treated with a required different regenerating fluid, whereby a more appropriate regeneration process can be performed.

Further, the filter regeneration pipe includes one filter regeneration pipe through which a fluid having substantially the same component as the handling fluid flows, and the valve device includes a filter unit connected to the regeneration pipe. At a stage immediately before the connection to the fluid pipe again, the switching may be performed so as to connect to a filter pipe through which a fluid having substantially the same component as the handling fluid flows. This allows the filter unit to be reconnected to the fluid pipe to be reconnected at the time of the connection without affecting the handling fluid in the fluid pipe by the connection.

The present invention is also directed to a filter device connectable to a fluid pipe through which a handling fluid flows, wherein the regenerating apparatus includes at least two filter units and a regeneration pipe through which a fluid for filter regeneration flows. A valve device for switching and connecting a filter unit between the fluid pipe and the regeneration pipe, wherein the regeneration apparatus includes a plurality of fluid sources for supplying a plurality of different types of filter regeneration fluids, A valve for selectively connecting one of the fluid sources to the regeneration pipe. In this filter device, the regeneration pipe can be switched to the required regeneration fluid source by the valve device, and more appropriate regeneration processing of the filter unit can be performed.

The present invention is also an apparatus for supplying a polishing liquid to a polishing apparatus, comprising: a raw liquid supply source; a raw liquid tank for supplying and storing a raw liquid from the raw liquid supply source; A stirring tank that mixes and stirs a polishing liquid stock solution supplied from a liquid stock solution tank and a diluting solution to form a polishing solution of a required concentration; , A second line connecting the polishing liquid stock tank and the stirring tank, and a third line for supplying the polishing liquid from the stirring tank to the polishing apparatus, the first to the first The line (3) is provided with a filter device for removing particles in the liquid passing therethrough, at least one of which is the filter device according to any one of claims 1 to 4. The present invention provides a polishing liquid supply device characterized by the following. According to this polishing liquid supply device, particles in the polishing liquid supplied to the polishing device can be reliably removed, and a favorable polishing operation can be performed.

[0015]

1 to 4 show a filter device F according to an embodiment of the present invention. The filter device F is provided with a piping of a polishing liquid supply device as shown in FIGS. It is attached to a predetermined position. This abrasive fluid supply device,
Mixing in which the stock solution supplied from the stock solution tank 10 via the stock solution line 12 and the stock solution supplied from the stock solution tank (not shown) via the stock solution line 14 are combined and stored as a stock solution of a predetermined concentration. Tank 16 and mixing tank 1
6, a pump 19 for circulating the abrasive fluid in the circulation path 18, and a circulation path 1
Extraction pipe 2 for supplying the polishing liquid from 8 to the polishing device
0 is provided.

As the stock solution of the polishing solution, for example, an acid, alkali or neutral solution containing particles of a predetermined particle size such as silica, alumina, cerium oxide, manganese dioxide or the like is used according to the object to be polished. As the solution, pure water, an acid, an alkali, a neutral chemical solution or the like having no impurities is usually used.
The stock solution line 12 and the diluent solution line 14 are provided with necessary on-off valves, pressure gauges, back pressure valves, flow meters, constant flow valves, orifices, and the like. A cleaning pipe and a polishing liquid sampling pipe may be provided for this. The circulation path 18 of the polishing liquid prevents the agglomeration of the abrasive grains by flowing the polishing liquid even while the supply of the polishing liquid is stopped. In the embodiment of FIG. It is also provided on the stock solution supply line 12. 5 to 7 show examples in which the filter devices F are individually provided in the raw liquid supply line 12 and the circulation path 22 of the raw liquid supply line, in the circulation path 18 of the abrasive liquid, and in the extraction pipe 20. However, these may be provided together.

The filter device F includes two filter units 30a and 30b which are connected to a polishing liquid line 32 and a regeneration line 34.
(See FIG. 3) Two-way two-position switching valve device 3 for switching to
1 and 2, a bottom plate and a cylindrical wall standing upright are mounted on a mounting plate 38 having an opening so as to pass through the opening, as shown in FIGS. , A disc-shaped fixed plate 42 and a movable plate 44 housed inside the first casing 40, and a second plate that pushes the movable plate 44 toward the fixed plate 42 via a guide mechanism 46. It has two casings 48 and a rotary actuator 50 for inverting the movable plate 44 every 180 degrees by supplying air.

The filter units 30a and 30b are, for example, a resin casing filled with a folded filtration membrane. Some filter membranes are provided with an auxiliary member made of resin in order to impart strength to the filtration membrane. Of course, some filter membranes are used without being folded.

The fixed plate 42 and the movable plate 44 are made of, for example, Si
It is made of a ceramic material mainly composed of C, and the sliding surfaces of each other are finished flat. By pressing both with a predetermined pressure, the sliding surfaces can be brought into close contact to prevent leakage of fluid. . Rotary actuator 50
Is mounted on the lower surface of the first casing 40 so as to protrude from the opening of the mounting plate 38, and its output shaft 51 is connected to the movable plate 44 through the shaft holes of the first casing 40 and the fixed plate 42. The material of the fixed plate 42 and the movable plate 44 is SiC
In addition, it is also possible to make it with a resin having low friction, such as a fluororesin.

The second casing 48 includes the first casing 4
0 is formed in a cylindrical shape so as to surround the cylindrical wall, and a holding portion 54 for holding the guide mechanism 46 through a seal ring (elastic ring) 52 is formed inside the upper portion. Have been. The guide mechanism 46 is disposed inside the second casing 48 so as to face the first guide member 58 and an annular first guide member 58 having an L-shaped cross section attached to an outer peripheral portion of the upper surface of the movable plate 44. It also has an annular second guide member 60 also having an L-shaped cross section, and a plurality of steel balls (bearing balls) 62 arranged between these guide members 58 and 60.

The seal ring 52 is connected to the second casing 48
Is fixed to the first casing 40 with the bolts 56, a predetermined surface pressure is applied between the fixed plate 42 and the movable plate 44 by an elastic force due to the deformation, and a sliding surface between the fixed plate 42 and the movable plate 44 is formed. To prevent liquid leakage from Thus, a guide mechanism 46 that rotatably holds the movable plate 44 while maintaining the surface pressure between the fixed plate 42 and the movable plate 44 is configured.

As shown in FIGS. 1 to 3, the first casing 40 includes two filter units 30 each.
The two sets of reciprocating flow paths communicating with a and 30b are formed to penetrate at symmetrical positions with respect to the center, and flow paths 62a, 62b, 64a and 64b are formed at the same position on the fixed plate 42,
On the other hand, the movable plate 44 also has two sets of flow paths 66a, 66b, 68a, 68b at positions corresponding to the flow paths of the fixed plate 42.
Are formed. Thus, the switching valve device 36 that switches the two flow paths to the two positions is configured. The filter units 30a, 30b are formed by filling a filter material in a cylindrical casing having ports at the upper and lower ends, and are detachably attached to the flow path of the movable plate 44 via a pipe 70 or a joint 72. It is connected to the. In this embodiment, the movable plate 44 is provided with the filter units 30a and 30a.
Since b is directly mounted, the configuration of the switching valve is greatly simplified. A cover 74 that covers the upper part of the filter device F is attached to the outer periphery of the top of the second casing 48.

The regeneration line 34 is for cleaning and regenerating the used filter units 30a and 30b.
As shown in the figure, on the outward path, the pH is about 10.0
A dilute KOH liquid source for adjusting H, a concentrated KOH liquid source having a pH of 11.0 or more, and a polishing liquid source are switchably connected, and the return path is connected to a vent pipe leading to a drain. Although not shown, each KOH liquid source has temperature control means having a function of adjusting the liquid temperature to a predetermined temperature in accordance with the detected value of the temperature sensor, and the concentration of the KOH liquid in accordance with the detected value of the pH sensor. Is provided to adjust the density to a predetermined value.

The operation of the filter device F constructed as described above will be described below.
An example in which alkaline SC-1 (trade name) freely dispersed and used in Example 1 is used will be described with reference to the process chart of FIG. In normal operation, the filter units 30a,
One (30a in FIG. 3) of the filter 30b is connected to the polishing liquid line 32 to filter solids in the polishing liquid, and the other filter unit (30b in FIG. 3) is connected to the regeneration line 34 to perform cleaning and regeneration. A process is taking place.

At a predetermined timing when the trapped amount of the filter unit connected to the polishing liquid line 32 reaches a predetermined value, the line is alternately switched between the filter unit and the filter unit connected to the regeneration line 34 and cleaned and regenerated. Perform
This switching timing is determined, for example, by a method of directly or indirectly measuring the amount of capture and switching based on the measured value, a method of predicting a processing time to reach the capture capability in advance and switching when the time is reached, and the like. There is. As the former, there are a method of measuring the pressure difference before and after the filter unit, a method of measuring the weight of the filter unit, a method of measuring the number of agglomerated particles in the slurry, and the like. Switching is performed by operating the rotary actuator 50 to rotate the movable plate 44 every 180 degrees. The abrasive liquid line 32 is provided with a filter unit having a high capturing capability after the washing and regenerating steps. It is performed continuously. The switching of the filter unit is automatically performed by a signal from an external controller.

In the regenerating line 34, the regenerating liquid is supplied to the filter from the same direction as the direction of the supply of the polishing liquid in the polishing liquid line 32, and the washing and regenerating steps are performed. This is, first, the rare KO
H solution at a predetermined pressure, flow rate and time, for example, 100 KPa
(1 kgf / cm2), supplied at about 10 l / min, about 2 min to wash away relatively easily removed abrasive grains attached to the filter. Thereafter, a concentrated KOH solution warmed to about 50 ° C., for example, 100 KPa (1 kgf / cm 2), 10 l /
min and 10 min to dissolve and remove the abrasive particles fixed to the filter. Further, a diluted KOH solution is added to, for example, 100 KPa (1 kgf / cm2), 10 l / min,
Supply for about 2 min to adjust the pH of the filter and wait in that state. When it is predicted that the switching of the filter units 30a and 30b is imminent after a predetermined processing time has elapsed, the abrasive liquid is supplied to the filter so that the abrasive liquid is included, and when the switching is performed, the abrasive liquid is Avoid rapid changes in pH and concentration.

By repeating the above steps, the polishing liquid can be continuously and automatically supplied without stopping the polishing liquid line 32 and without performing the step of removing the filter units 30a and 30b from the joints, which has poor workability. Can be supplied. It should be noted that the filter units 30a, 30b are determined by the lapse of the service life of the filter units 30a, 30b.
When replacing the filter units 30a, 3
0b is switched to the regeneration line 34, and after performing a short-time washing and draining process in the regeneration line 34, the cover may be removed, the joint may be removed, and the replacement operation may be performed. Since the washing and draining steps have been performed, the abrasive fluid is not scattered, and the replacement can be performed with good workability.

In the above embodiment, the same regenerating liquid (KOH) as the chemical liquid for dispersing the abrasive grains in the polishing liquid is used, which is desirable.
A chemical solution such as NH4OH which does not change the composition of the polishing liquid and has good replaceability may be used. In the above embodiment, KOH
Is heated in advance, but a heater for controlling the heating temperature of the regeneration pipe or the filter device itself may be provided, or a member for controlling the temperature of the regeneration pipe or the filter for maintaining the temperature may be provided. Further, the method of the present invention is not limited to the above-described switchable device,
Needless to say, it may be used for cleaning and regenerating by removing it from the pipe. In the above-described embodiment, the filter regeneration direction is the same as the polishing liquid supply direction. However, the preferred filter regeneration can be performed similarly by performing filter cleaning and regeneration from the opposite direction. In this case, in the step of replacing the cleaning liquid in the filter with the polishing liquid, it is more preferable to supply the polishing liquid from the positive direction.

[0029]

EXAMPLE A test was conducted to dissolve solids deposited on a filter when the polishing liquid was alkaline SC-1 (trade name) containing colloidal silica and KOH. In Table 1, DIW in the first row is pure water at a temperature of 20 ° C, and the others have a temperature of 20 to 50 ° C and a pH of 12.8 to
10.7 KOH aqueous solution. In this result, p
Good results were obtained when H was 11.3 or more and the temperature was 40 ° C. or more.

[Table 1]

FIG. 8A shows an experimental example in which a fold type pleated filter is used as the filter unit. The differential pressure is measured while a slurry (abrasive liquid) is supplied at a constant flow rate, and a predetermined pressure is measured. When the differential pressure is reached, KO
Washing was performed using an H aqueous solution as a regenerating solution. FIG. 8 (a)
The figures shown as Medium, Wash 1-3 show the fold structure of the filter and the degree of solids remaining on the fold of the filter immediately after each wash. FIG. 8B shows the temperature and pH of the regenerating solution and the method of washing. According to this, the effect is hardly obtained in the cleaning 1 and the effect is not maintained in the cleaning 2, but the effect is maintained in the cleaning 3, and a high correlation with the temperature and the pH is observed.

FIG. 9 shows the results of a test performed step by step by attaching a membrane type filter as the filter unit to the apparatus shown in FIG. As a regenerating solution, KOH having a pH of 13.5 was used after warming to a temperature of 50 ° C. Measure the differential pressure of the filter unit, and
(0.6 kgf / cm2), a regeneration treatment for 2 minutes was performed, and the filtration of the slurry was continued. By this regeneration processing, the differential pressure is 30 KPa (0.3 kgf / cm
2), after which a predetermined amount of filtering could be continued, thus greatly extending the life of the filter.

FIG. 10 shows an embodiment of a regenerating liquid supply apparatus having a regenerating liquid concentration adjusting function and a temperature raising function for performing the above-described method of regenerating a filter unit. It has a regulating tank 80 to which a pure water supply pipe 82 and a high concentration KOH supply pipe 84 are connected via on-off valves 86 and 88, respectively. However, there is a pH meter 92 inside the tank.
Is provided. Further, a pump 96 and an on-off valve 98 are provided in a discharge pipe 94 from the adjustment tank to the filter device F.
And an in-line heater 100. The in-line heater 100 raises the temperature of the passing liquid at a stretch by a halogen lamp, a heating wire or the like.

By operating the open / close valves 86 and 88 in accordance with the values indicated by the load cell 90 and the pH meter 92, a constant concentration of the regenerating liquid is always stored in the tank 80. This adjustment tank 80
The KOH solution adjusted in the above is transported by a pump at the same time as the cleaning operation of the filter device F is started, and is heated to, for example, 50 ° C. in one pass by an in-line heater, so that the filter device F
Supplied to

FIGS. 11 and 12 show a modification of the filter device F. The output shaft 51 of the rotary actuator 50 is fixed by a fixed plate 42, a movable plate 44, and a fixed pin 45 on the upper portion of the movable plate. The movable plate 44 is slidable with respect to the output shaft 51, but is connected so as to be rotationally driven by the output shaft. An O-ring 102 for sealing is mounted between the movable plate 44 and the holding plate 43. Also, the output shaft 5 of the rotary actuator 50
A predetermined surface pressure is applied between the fixed plate 42 and the movable plate 44 by a spring 55 attached between the spring retainer 53 at one end and the retainer plate 43, and liquid leakage during this period is prevented.

In this modification, the filter units 30a,
30b is adapted to be fixed to the cover 74,
It is connected to the flow path of the holding plate by a flexible pipe. Of course, like the other embodiments, these filter units can be fixed to the holding plate.

FIG. 13 shows a filter device according to another embodiment of the present invention. In contrast to the previous embodiment in which two filter units are switchably mounted,
Here, four filter units 30a, 30b, 30
c and 30d are mounted axially symmetrically. The pipe connected to this is a single system of the polishing liquid line 32 connected to the first position, but different regeneration lines 34a, 34b, 34c are connected to the other three positions, respectively. That is, a diluted KOH solution pipe is connected to the second position, and a concentrated KOH solution pipe and a diluted KOH solution pipe are connected to the third position.
An OH solution pipe is connected, and a replacement abrasive fluid supply pipe is connected to the fourth position.

In this filter device, the steps of cleaning and regenerating the filter unit are performed by sequentially performing different steps at respective positions. As a result, sufficient time can be taken for cleaning and regeneration, and the liquid supply line for cleaning and regeneration can be simplified. In this example, a configuration in which four positions can be switched is shown.
The positions above the position may be arranged equally on a concentric circle so as to be switchable.

FIG. 14 shows a filter device according to still another embodiment of the present invention.
b has a switching valve 84 of a type that rotates the shaft 82 on which the b is formed. The shaft is rotatably supported at both ends by through holes 90 formed in a pair of fixed plates 86, 88, and has two flow paths 80a, 80b extending inside along one axial direction and open at one end and at the center. Are provided at two positions symmetrical with respect to the axis.

Two filter units 30a and 30b are mounted on the outer periphery of the shaft 82 between the fixed plates 86 and 88. Filter units 30a, 30b
Is, for example, a fan-shaped cylindrical body having a substantially semicircular cross section, and has inlet and outlet ports formed on the inner surface. Fixing plate 8
In the through holes 90 of the 6, 88, a flow path is formed to be connected to a port on the end side of the flow path of the shaft, and the other end thereof is connected to the polishing liquid line 32 or the regeneration line.
A seal member such as a seal ring is attached to a predetermined required portion, and an actuator (not shown) for rotating or reversing the shaft 82 every 180 degrees is provided.

As described above, it is needless to say that the function and effect of the present invention can be obtained even when the switching valve whose flow path is opened on the outer peripheral surface of the rotating body 82 is used similarly to the previous embodiment. The type of the switching valve is not limited to the rotary type described above, and may be a type that reciprocates linearly. In this case, a regeneration line is required on both sides of the polishing liquid line.

FIG. 17 shows another embodiment of the polishing liquid supply device according to the present invention. The configuration of this device is almost the same as that of the embodiment shown in FIGS. 5 to 7, but a system for filtering the stock solution stored in the stock solution tank 10 in advance is added. This system includes a tank 100 for storing a primary polishing liquid concentrate before filtration, a pump 102 for feeding the primary polishing liquid concentrate from the tank 100 to the tank 10 through a primary polishing liquid line, and a filter unit 30d. are doing. Filter unit 30d
Means that particles having a size of 5 μ or more in the primary stock solution are reduced to about 95%.
For example, a filter membrane folded in a resin casing (specifically, a pleated type manufactured by Pall Corporation (model HDC I
I)) can be formed by filling. Tank 100
When a predetermined amount of the stock solution is supplied to the tank 10 from the
The valve is switched by a control device (not shown), and a KOH aqueous solution of about 50 ° C. as a cleaning liquid or a regenerating liquid is supplied to the filter unit through a KOH supply line 104, and the filter unit is cleaned. In order to reduce the consumption of KOH aqueous solution, at the beginning of KOH aqueous solution supply,
The liquid passed through the filter unit is drained into the drain line 10.
6 and then discarded (not shown)
Returned to the tank. When the cleaning of the filter unit is completed, the valve is switched again, and the supply of the abrasive liquid material from the tank 100 to the tank 10 is restarted.

Pressure sensors 120 and 122 are provided upstream and downstream of the filter unit 30d, respectively.
The pressure difference on both sides of the filter unit can be measured. When this pressure difference becomes equal to or greater than a predetermined value, it is determined that the filter unit 30d has clogged. If the filter unit 30d becomes clogged during the supply of the undiluted polishing liquid, the supply of the liquid is stopped, and the filter unit is washed and regenerated or replaced with a new one. In an actual device, when the pressure reaches 30 KPa, it is determined that the filter unit is clogged.

As in the above-described polishing liquid supply apparatus according to the other embodiment, the filtered polishing liquid stock solution stored in the tank 10 is supplied to the mixing tank 16 where it is supplied from a diluting liquid tank (not shown). Mixed with the diluent
After being adjusted to the appropriate concentration, the abrasive liquid supply line 130 (a part of the circulation path 18 in the embodiment shown in FIGS. 5 to 7,
And a portion corresponding to the extraction pipeline 20) to the polishing devices P1 and P2. A filter device including two filter units 30a and 30b and a valve device 36 is provided on the polishing liquid supply line 130, as shown in FIG. Pressure sensors 126 and 128 are provided on the upstream and downstream sides of the filter device so that a pressure difference between both sides of the filter device can be measured. Filter units 30a, 30a
Is, for example, a filtration membrane folded in a resin casing (specifically, a pleated type (model CM
Pure)). This filter unit transmits through the filter unit 30d,
Alternatively, particles having a size of 5 μm or more that are agglomerated after permeation are removed. Pressure sensors 126 and 1
When the pressure difference detected by the filter 28 reaches a predetermined value, it is determined that the used filter unit 30a or 30b is clogged. When such a determination is made, the valve device 36 is switched by a control device (not shown), and a KOH aqueous solution is supplied to the clogged filter unit through the regeneration line 34.
The other filter unit is connected to the polishing liquid supply line 130. In order to reduce the consumption of the KOH aqueous solution, at the beginning of the supply of the KOH aqueous solution, the KOH aqueous solution passed through the filter unit is discarded, but thereafter, returned to a KOH aqueous solution tank (not shown).

The polishing liquid supply line 130 further has another filter unit 30e at a position close to the polishing apparatus. This filter unit is a filter unit 30
a, 30b, and the filter units 30a, 30b,
It is for removing particles generated in the polishing liquid after passing through 0b, but in fact, there is almost no such particles,
As shown in FIG. 18, a considerable amount of polishing liquid can be processed. Therefore, the filter unit 30e does not need to be specially provided with a device for regenerating the filter unit 30a or 30b as in the case of the filter unit 30a, and may be replaced with a new one periodically.

In the polishing liquid supply device shown in FIG. 17, since a plurality of filter units are provided along the polishing liquid supply line, most of the coarse particles can be removed. FIG. 19 shows a case where a semiconductor substrate is polished by a polishing apparatus using a polishing liquid.
This shows the number of defects generated on the surface to be polished of the substrate. That is, when the abrasive fluid supplied by the abrasive fluid supply device shown in FIG. 17 is used, the number of generated defects is much smaller than when the abrasive fluid supplied by the device without the filter unit is used. You can see that. The number of defects is calculated by KL
The measurement was performed using a measuring instrument manufactured by ATencor, SFS6420.

[0046]

As described above, according to the present invention, the filter that has captured particles is moved to the regeneration pipe and the regeneration process is performed here, thereby facilitating the replacement of the filter in a more purified state. And reliably. Furthermore, by performing a regeneration process in a stepwise manner, a continuous filter process is performed without replacement, solid particles contained in fluid such as abrasive fluid in the pipe are reliably captured, and a high-quality fluid is supplied. Further, it is possible to provide a filter device capable of performing a stable operation without clogging. According to another aspect of the present invention, the solidified abrasive grains can be redissolved to facilitate cleaning and removal, and the filter unit can be regenerated quickly. Therefore, the polishing process can be continued and automated. Can be promoted.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a filter device of the present invention.

FIG. 2 is a plan sectional view of the embodiment of FIG. 1;

FIG. 3 is a diagram schematically illustrating the filter device according to the embodiment of FIG. 1;

FIG. 4 is a flowchart illustrating an operation of the filter device according to the embodiment of FIG. 1;

FIG. 5 is a diagram showing an example of an abrasive liquid supply device using the filter device according to the embodiment of the present invention.

FIG. 6 is a diagram showing another example of an abrasive liquid supply device using the filter device according to the embodiment of the present invention.

FIG. 7 is a diagram showing still another example of the abrasive liquid supply device in which the filter device according to the embodiment of the present invention is used.

FIG. 8 is a graph showing the results of a test showing the effect of the method of the present invention.

FIG. 9 is a graph showing the results of a test showing the effect of the method of the present invention.

FIG. 10 is a diagram showing an example of a configuration of a regenerating liquid supply source used in the filter device of the present invention.

FIG. 11 is a diagram showing a filter device according to another embodiment of the present invention.

FIG. 12 is a plan view of the filter device of FIG. 11;

FIG. 13 is a view showing a filter device according to still another embodiment of the present invention.

FIG. 14 is a view showing a filter device according to still another embodiment of the present invention.

FIG. 15 is a sectional view showing a conventional polishing apparatus.

FIG. 16 is a view showing a conventional filter device.

FIG. 17 is a view showing still another example of the abrasive liquid supply device using the filter device according to the embodiment of the present invention.

18 is a diagram showing the relationship between the amount of abrasive liquid supplied to the filter unit and the differential pressure before and after the filter unit at the final stage in the abrasive liquid supply device of FIG. 17;

FIG. 19 is a diagram showing the number of defects generated when a semiconductor substrate polished using different types of polishing liquids is polished.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 stock solution tank liquid 12 stock solution line 14 diluent line 16 mixing tank 18, 22 circulation path 19 pump 20 extraction pipe 30 a, 30 b filter unit 36 switching valve device F filter device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B24B 57/02 B01D 35/02 A

Claims (5)

[Claims] 1. A filter device connectable to a fluid pipe for flowing a handling fluid and a regeneration pipe for flowing a filter regeneration fluid, comprising: at least two filter units; and one of the filter units being the fluid pipe. And a valve device for selectively connecting one of the other filter units to the regeneration pipe at the same time. 2. The filter regeneration pipe according to claim 1, wherein the filter regeneration pipe has a plurality of regeneration pipes through which different filter regeneration fluids flow, and in the valve device, each filter unit is sequentially connected from the fluid pipe to the different regeneration pipe. ,afterwards,
The filter device according to claim 1, wherein the filter device is switchable so as to be connected to the fluid pipe again. 3. The filter regeneration pipe includes one filter regeneration pipe through which a fluid having substantially the same component as the handling fluid flows, and the valve device includes a filter unit connected to the regeneration pipe. Immediately before being connected to the fluid pipe again, switching is performed so as to connect to a filter pipe through which a fluid having substantially the same component as the handling fluid flows. The filter device according to claim 2, wherein the filter unit to be connected is regenerated at the time of the connection so that the handling fluid in the fluid pipe is not affected by the connection. 4. A filter device connectable to a fluid pipe through which a fluid to be handled flows, comprising: at least two filter units; a regeneration apparatus having a regeneration pipe through which a fluid for filter regeneration flows; A valve device for switching connection between a fluid pipe and a regeneration pipe, wherein the regeneration apparatus comprises: a plurality of fluid sources for supplying a plurality of filter regeneration fluids of different types; A valve for selectively connecting one to the regeneration pipe. 5. A polishing liquid supply device for a polishing apparatus, comprising: a polishing liquid liquid supply source; a polishing liquid liquid tank for supplying and storing a raw liquid from the polishing liquid liquid supply source; A polishing liquid stock solution, and a stirring tank that mixes and stirs a diluting solution to produce a polishing solution of a required concentration, and a first line connecting the polishing solution stock solution supply source and the polishing solution stock solution tank, A second connecting the grinding stock solution tank and the stirring tank;
And a third line for supplying the polishing liquid from the stirring tank to the polishing apparatus. The first to third lines remove particles in the liquid passing therethrough. 5. A polishing liquid supply device, comprising: a filter device, wherein at least one of the filter devices is the filter device according to any one of claims 1 to 4.