JP2006051501A - Method and apparatus for removing object to be removed from fluid, method for producing wafer and method for producing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that it is difficult to control the thickness of a second filter film by using an air bubble generating unit for hindering the filtering capacity of a filter from being deteriorated owing to, for example, the clogging of the second filter film formed on the surface of the filter. <P>SOLUTION: According to an apparatus for removing an object to be removed from fluid and a method for removing the object to be removed using the apparatus, air diffusing pipes 26, 27, 28 are arranged at the bottom of an original water tank 1. Air of the same pressure is sent into each of air diffusing pipes 26, 27, 28 from both ends of each pipe, so that the quantities of air bubbles to be discharged from air diffusing pipes 26, 27, 28 are uniformized with one another. As a result, the second filter film 21 to be formed on the surface of the filter 4 can be adjusted and the filtering capacity of the filter can always be kept at a constant optimum value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is for filtering a fluid containing an object to be removed while air blowing through a second filter film formed on the filter.

  At present, reducing industrial waste is an important theme from an ecological point of view and is a corporate issue. There are various types of wastewater and sewage in this industrial waste.

  Hereinafter, a substance containing a substance to be removed in a fluid such as water or chemicals will be referred to as “drainage”. These wastewaters are processed as industrial waste by removing the object to be removed by an expensive filtration device or the like, and the wastewater becomes a clean fluid and reused or cannot be removed. In particular, water is returned to the natural world such as rivers and seas in a clean state or reused.

  As can be seen from this, wastewater treatment technology is an important problem from the viewpoint of environmental pollution and from the viewpoint of recycling, and a system with low initial cost and low running cost is urgently desired.

  As an example, wastewater treatment in the semiconductor field will be described below. In general, when grinding or polishing a plate such as metal, semiconductor, ceramic, etc., fluid such as water is considered in consideration of prevention of temperature rise of equipment, improvement of lubricity, adhesion of grinding or cutting waste to the plate. Is supplied.

  On the other hand, with the theme of “environmentally friendly”, wastewater mixed with grinding or polishing waste of the semiconductor wafer is filtered and returned to the natural world as clean water, or recycled wastewater is concentrated. Have been recovered.

  In the current semiconductor manufacturing, there are two types of wastewater treatment mainly containing Si, which is a combination of coagulation sedimentation method and filter filtration and centrifuge. Yes.

  However, both of the above two methods have a problem that the running cost such as the electric cost of the motor and the replacement cost of the filter is very high and the initial cost is also very high (see, for example, Patent Document 1).

  In view of the above problems, the present applicant has developed a system with very low initial cost and running cost. The outline is shown below.

  First, the mechanism of this system will be described.

  Reference numeral 1 in FIG. 5 is a raw water tank. Above the tank 1, a pipe 2 is provided as raw water supply means. This pipe 2 is a place where a fluid mixed with an object to be removed passes. For example, in the semiconductor field, waste water (raw water) mixed with an object to be removed flowing out from a dicing apparatus, a back grinding apparatus, a mirror polishing apparatus, or a CMP apparatus passes. The drainage will be described as drainage mixed with silicon waste flowing from the dicing apparatus.

  A plurality of filters 4 are installed in the raw water 3 stored in the raw water tank 1. Below this filter 4, for example, a bubble generating device 5 such as a bubbling device in which a small hole is made in a pipe is provided, and the position of the hole is adjusted so as to pass through the surface of the first filter membrane. Has been. 6 is an air blow.

  The pipe 7 fixed to the filter 4 passes through the filtered fluid filtered by the filter 4 and passes through the first valve 9 to the raw water tank 1 side and to the reuse (or drained) side. It is selectively transported to the pipe 11 that heads. A second pipe 12, a third pipe 13, a fourth pipe 14 and a fifth pipe 15 are attached to the side wall and the bottom surface of the raw water tank 1.

  The raw water 3 supplied from the pipe 2 is stored in the raw water tank 1 and filtered by the filter 4. Bubbles pass through the surface of the first filter membrane 20 (see FIG. 6) attached to this filter, and the silicon debris trapped in the first filter membrane 20 is moved by the rising force and rupture of the bubbles. The filtration capacity is maintained so as not to decrease.

  Further, when the first filter membrane 20 is newly attached, the filtration is resumed after being stopped for a long time due to a holiday, or when silicon waste is mixed in the pipe 7, the valve 9 is used to filter the fluid. Is circulated through the pipe 10 to the raw water tank 1. Otherwise, the valve 9 is switched to the pipe 11 and the filtered fluid is reused.

  If the silicon scrap is higher than the predetermined mixing rate, the filtration fluid is determined to be abnormal water, and the circulation is automatically started or the pump is stopped and the filtration is stopped. Further, when circulating, the supply of fluid from the pipe 2 to the tank 1 may be stopped in consideration of the overflow of the drainage from the tank 1.

  The sensor 17 constantly senses silicon scrap. The amount of silicon waste in the filtered fluid can be detected by detecting the transparency of the filtered fluid using an optical sensor with a light receiving / light emitting element as the sensor 17. The light emitting element may be a light emitting diode or a laser. The sensor 17 may be attached in the middle of the pipe 7 or in the middle of the pipe 10.

  On the other hand, the raw water tank 1 is concentrated with time. And when it becomes a desired density | concentration, a filtration operation | work is stopped, it is made to coagulate, and it is left to stand. Then, the raw water 3 in the tank is roughly divided into layers. In other words, from the upper layer to the lower layer, it is distributed from a slightly transparent water to a completely non-transparent liquid with silicon waste. These are collected using pipes 12-15 separately.

  As described above, the system of FIG. 5 includes the raw water tank 1, the filter 4, and the small pump 8.

  Next, the structure of the filter 4 employed in this system will be described.

  Reference numeral 19 shown in FIG. 6A denotes a frame having a frame shape, and the first filter film 20 is bonded and fixed to both surfaces of the frame 19. In the inner space 18 surrounded by the frame 19 and the first filter membrane 20, the filtered fluid filtered by the first filter membrane 20 is generated by sucking the pipe 7. The filtered fluid is taken out through the pipe 7 which is sealed and attached to the frame 19. Of course, the first filter membrane 20 and the frame 19 are completely sealed so that drainage does not enter the space from other than the first filter membrane 20.

  Since the first filter film 20 in FIG. 6A is a thin resin film, when it is sucked, the first filter film 20 warps inward and may be destroyed. Therefore, in order to make the space 18 as small as possible and increase the filtering capacity, it is necessary to form a large number of the spaces 18. This is shown in FIG. 6 (B). Although only nine spaces 18 are shown in the figure, many spaces are actually formed. The actually employed first filter membrane 20 is a polyolefin-based polymer membrane having a thickness of about 0.1 mm, and the thin first filter membrane 20 is formed in a bag shape as shown in the figure. In 6 (B), it was indicated by FT. A frame 19 in which the pipe 7 is integrated is inserted into the bag-like filter FT, and the frame 19 and the filter FT are bonded together. Reference numeral RG denotes pressing means that presses the frame 19 to which the first filter film 20 is bonded from both sides. The first filter film 20 is exposed from the opening OP of the pressing means.

  FIG. 7 conceptually shows the operation of the filter 4. Here, if the pipe 7 side is sucked with a pump or the like, water flows and is filtered as shown by an arrow without hatching.

Further, the silicon filter is captured by the first filter film 20 and the layer of the silicon scrap captured by the film 20, whereby the second filter film 21 is formed in the vertically placed filter device. Will be. At this time, since the second filter film 21 is attached with silicon waste, by applying an external force to the second filter film 21, the second filter 21 can be removed or the second filter film 21 can be removed. The surface layer can be removed. Further, this removal can be easily realized by rubbing the surface using the rising force of bubbles or by a stirrer or the like. With this external force, the filtration capacity of the second filter membrane 21 is constantly refreshed and maintained at a substantially constant value.
Japanese Patent Laid-Open No. 2001-038352 (page 10-13, FIG. 1-3)

  As described above, in the conventional bubble generating device 5 of the filtration device, the bubble generating device 5 is an air diffuser such as a vinyl chloride pipe, and a large number of holes are formed in the air diffuser located below the filter 4. The bubble generating device 5 was connected to the blower 6, and air was sent from the blower 6 to the bubble generating device 5. As a result, the second filter film 21 formed on the surface of the filter 4 is adjusted by the bubbles generated from the holes of the air diffusion tube of the bubble generating device 5.

  However, since one end of the bubble generating device 5 is sealed and the other end of the bubble generating device 5 is installed in the blower 6, air is always sent only from the other end connected to the blower 6. It was. Therefore, in the bubble generating device 5, a large amount of bubbles can be obtained on the side closer to the blower 6, but sufficient bubbles are not generated on the side farther from the blower 6 than on the closer side. As a result, there is a problem in that the second filter film 21 formed on the surface of the filter 4 has a different thickness and properties depending on the position with respect to the bubble generating device 5 and cannot obtain a sufficient filtering ability.

  Furthermore, as described above, a plurality of filters 4 are installed in the raw water tank 1, but the conventional bubble generator 5 cannot uniformly generate bubbles for the plurality of filters 4. As a result, there is a problem in that the second filter film 21 formed on the surface of the filter 4 has a different thickness and properties depending on the position with respect to the bubble generating device 5 and cannot obtain a sufficient filtering ability.

  The present invention has been made in view of the above-described conventional problems. In the fluid removal object removal method of the present invention, a plurality of filters are immersed in a fluid containing the removal object, and the fluid is contained in the filter. In the fluid removal object removal method for removing the removal object by passing the filter, by reducing the interval between the filters, the bubbles generated from below the filter are deformed and the gap between the filters is reduced. It is characterized by passing.

  Furthermore, in the fluid removal object removal method of the present invention, the bubbles are deformed by the filter, and an external force is applied to the surface of the filter by a resistance against the deformation of the bubbles.

  Furthermore, in the fluid removal object removal apparatus of the present invention, in the fluid removal object removal apparatus that filters the fluid by immersing a plurality of filters in the fluid containing the removal object, the filter includes: The interval b is set so that bubbles arranged substantially at a predetermined interval b and passing between the filters are deformed.

  Further, in the fluid removal object removing device of the present invention, the bubble generating device provided below the filter is arranged so as to be orthogonal to the filter surface.

  Furthermore, in the wafer manufacturing method of the present invention, a plurality of filters are immersed in a fluid generated when an ingot is machined into a wafer shape, and the fluid is passed through the filter, thereby causing the machining. In the wafer manufacturing method of removing the object to be removed and reusing the filtered fluid, by narrowing the interval between the filters, bubbles generated from below the filters are deformed and the gaps between the filters are reduced. It is characterized by passing.

  Furthermore, in the method for manufacturing a semiconductor device according to the present invention, a plurality of filters are immersed in a fluid generated when a semiconductor wafer is machined, and the fluid is passed through the filter, so that the substrate generated by the machining is generated. In a method of manufacturing a semiconductor device that removes a removed substance and reuses the filtered fluid, by reducing the interval between the filters, air bubbles generated from below the filters change the shape of the air bubbles between the filters. It is characterized by passing.

  As described above, according to the fluid removal object removal apparatus and the removal object removal method using the fluid removal apparatus of the present invention, the following excellent effects can be obtained.

  First, in the fluid removal object removal apparatus, the air diffuser pipes are formed to extend in a direction perpendicular to the plurality of filters installed in the raw water tank. By being in this positional relationship, a plurality of filters can be dealt with with a small number of air diffusers, so that the filtering device itself can also have a simplified structure.

  Second, in the fluid removal object removal apparatus, both ends of a small number of diffuser pipes installed at the bottom of the raw water tank are connected, and further connected to one pipe. And by connecting the pipe to the blower, air can be fed from both ends of all the diffuser pipes with the same pressure. Thereby, air bubbles can be generated uniformly with respect to the filter in the raw water tank.

  Thirdly, in the fluid removal object removal method, the distance between the filters installed in the raw water tank is set smaller than the diameter of the bubbles generated from the air diffuser. As a result, when the bubbles generated from the air diffuser pass between the filters, a resistance force against the force that is compressed is generated. As a result, when air bubbles pass between the filters, it is possible to prevent clogging of the filter by reliably applying an external force to the second filter membrane, and it is possible to always maintain the filtration capability of the filter. A removal object removal method can be realized.

  Fourth, in the fluid removal object removal method, as described above, the second filter film thickness formed on the surface of the filter can be generated uniformly with respect to the filter in the raw water tank. Can be controlled to a uniform thickness. As a result, it is possible to realize a fluid removal object removal method capable of always maintaining the filtration capability of the filter.

  Fifth, in the fluid removal object removal method, the amount of bubbles when the filtration device is ON can be made smaller than the amount of bubbles when continuously performing the filtration. As a result, the second filter membrane can be brought into the normal second filter membrane state at an early stage without destroying the second filter membrane when the filtration device is turned on, so that the filtration capability of the filter can be reduced for a long time. Can be maintained over time.

  1-4 is a figure for demonstrating the Example of the bubble generator which is this invention, In the figure, the part which attached | subjected the code | symbol same as the above-mentioned conventional Example represents the same thing, The mechanism for removing the object to be removed from the liquid is the same as the conventional mechanism. Therefore, the description of the mechanism described in the conventional example is omitted here.

  First, with reference to FIGS. 3 and 4, the first filter film 20 and the second filter film 21 described briefly in the conventional example with reference to FIG. 7 will be described in detail.

  The present invention removes a fluid (drainage) mixed with an object to be removed such as a metal, an inorganic substance, or an organic substance with a filter made of the object to be removed. For example, the object to be removed is a crystal ingot formed into a wafer. It occurs when slicing, dicing a semiconductor wafer, back grinding, CMP (Chemical-Mechanical Polishing), or wafer polishing.

  This object to be removed corresponds to organic substances such as Si, oxidized Si, Al, SiGe, sealing resin, and other insulating materials and metal materials. In the compound semiconductor, a compound semiconductor such as GaAs is applicable.

  Recently, dicing has been adopted in the manufacture of CSP (chip scale package). In this method, the surface of the wafer is coated with a resin, and the finally sealed resin and the wafer are diced together. There is also a type in which semiconductor chips are arranged in a matrix on a ceramic substrate, the resin is coated including the ceramic substrate, and the sealed resin and the ceramic substrate are finally diced. When these are also diced, an object to be removed is generated.

  On the other hand, there are many places where removed objects are generated even outside the semiconductor field. For example, in an industry that uses glass, in a liquid crystal panel, a panel of an EL display device, and the like, glass waste generated by dicing a glass substrate, polishing a side surface of the substrate, and the like corresponds to an object to be removed. In addition, electric power companies and steel companies employ coal as a fuel, which corresponds to powder generated from coal, and further, powder mixed in smoke emitted from the chimney corresponds to the object to be removed. This is also the case for powders generated from processing minerals, gemstones, and tombstones. Furthermore, metal scraps generated when processing with a lathe, ceramic scraps generated by dicing, polishing, etc. of a ceramic substrate also correspond to objects to be removed.

  These objects to be removed are generated by processes such as polishing, grinding, or pulverization, and a fluid such as water or chemicals is flowed for the purpose of removing the objects to be removed. Therefore, the object to be removed is mixed in this fluid.

  In the following, there are various types of fluids and objects to be removed as described above. Here, it is assumed that water is used as the fluid and the objects to be removed are included in the water. Go.

  Reference numeral 20 in FIG. 3 denotes a first filter film, and 22 denotes a filter hole. The film formed in a layered manner on the exposed portion of the filter hole 22 and the surface of the first filter film 20 is the objects to be removed 23 and 24, and these objects to be removed 23 and 24 cannot pass through the filter hole 22. The object to be removed 23 is divided into small objects to be removed 24 that can pass through the filter holes 22. In the figure, a black circle represents a small object to be removed 24 that can pass through.

  The first filter film 20 that can be used here can be either organic polymer type or ceramic type in principle. However, here, a polyolefin polymer film was used.

  Above the first filter membrane 20 in FIG. 3, there is waste water mixed with an object to be removed, and below the first filter membrane 20, a filtered fluid filtered by the first filter membrane 20 is generated. ing. In order to flow the waste water in the direction of the arrow and filter the waste water using the first filter membrane 20, the water is naturally dropped or pressurized and moved downward in the figure. Further, drainage is sucked from the side where the filtering fluid is present. Further, the first filter film 20 is arranged horizontally, but may be placed vertically as shown in FIG.

  As described above, as a result of pressurizing or sucking the wastewater through the filter membrane, the wastewater passes through the first filter membrane 20. At that time, a large object to be removed 23 that cannot pass through the filter hole 22 remains on the surface of the first filter film 20.

  In the present invention, a layer in which an object to be removed is captured and left on the surface of the first filter film 20 is used as the second filter film 21.

  Objects to be removed generated by machining such as grinding, polishing or pulverization are distributed within a certain range (size), and the shapes of the objects to be removed are different. In addition, objects to be removed are randomly located in the waste water in which the first filter film 20 is immersed. A large object to a small object to be removed moves irregularly to the filter hole 22. At this time, an object to be removed 24 smaller than the filter hole 22 passes, but an object to be removed 23 larger than the filter hole 22 is captured. The captured large object to be removed 23 becomes the first layer of the second filter film 21, and this layer forms a filter hole smaller than the filter hole 22, and the large object to be removed 23 passes through this small filter hole. Small objects to be removed 24 are captured. At this time, since the shapes of the objects to be removed are different from each other, gaps of various shapes are formed between the objects to be removed, and water moves through the gaps and is finally filtered. The This is very similar to the good drainage of sandy beaches.

  The second filter film 21 grows gradually while randomly capturing small objects to be removed 24 from the large objects to be removed 23, and traps the small objects 24 while securing a water (fluid) passage. become. In addition, since the second filter film 21 remains in a layer form and the object to be removed can be easily moved, bubbles are allowed to pass near the layer, a water flow is applied, a sound wave or an ultrasonic wave is applied, By applying mechanical vibration or rubbing with a squeegee or the like, the surface layer of the second filter membrane 21 can be easily moved to the drain side. In other words, even if the filter capacity of the second filter film 21 is lowered, there is a merit that the capacity can be easily restored by applying an external force to the second filter film 21. In other words, the cause of the decrease in the filter capacity is mainly clogging, and the removal target on the surface layer of the second filter film 21 that causes the clogging is moved again into the fluid. Can be clogged.

  However, when the first filter film 20 is newly attached, the layers of the objects to be removed 23 and 24 (second filter film 21) are not formed on the surface of the first filter film 20. When a thin layer of the second filter film 21 is formed on one filter film 20, a small object to be removed 24 passes through the filter hole 22. At this time, the filtered fluid is returned to the side where the drainage is stored again, and the process waits until it is confirmed that the small object to be removed 24 is captured by the second filter membrane 21. After confirmation, small objects to be removed such as the small objects to be removed 24 that have passed through are captured one after another, and the wastewater is filtered with a predetermined cleanliness.

  Furthermore, in the present invention, when the second filter membrane 21 is not formed or when a small object to be removed 24 remains in the filtered fluid, the filtered fluid is returned to the drainage side. During the returning process, the objects to be removed 23 and 24 trapped in the filter holes 22 grow as layers on the surface of the first filter film 20, and the second filter on the surface of the first filter film 20. The filter membrane 21 creates various filter pore diameters, and traps those having a small particle diameter and a large particle diameter one after another. Then, it gradually becomes thicker, traps small objects to be removed 24 that have passed through the first filter membrane 20, the same size as the small objects to be removed 24, and objects to be removed that are smaller than this. It becomes a clean state with no object to be removed.

  FIG. 4 shows this state. Then, after confirming that an object to be removed of a desired size is not mixed in the filtered fluid (and that the amount is smaller than a predetermined degree of mixing), the filtered fluid may be reused. Furthermore, the filtered fluid may be returned to nature.

  Further, when the small object to be removed 24 remains in the filtered fluid, the filtered fluid is not returned, but is transferred to another tank, and the object to be removed is about the same size as the small object to be removed 24 or the object to be removed 24. After confirming that the removed matter is captured, the subsequent filtered fluid may be reused or returned to nature.

  Next, a method for removing an object to be removed according to the present invention will be described with reference to FIGS.

  As described above, the cause of the decrease in the filter capacity is mainly clogging, and the object to be removed on the surface layer of the second filter film 21 that causes the clogging is moved again into the fluid. Clogging can be eliminated.

  FIG. 7 shows an example in which the rise of bubbles is used as a method of removing the second filter film 21. The bubble rises in the direction of the arrow indicated by the diagonal lines, and the rising force of the bubble and the bursting of the bubble directly apply an external force to the object to be removed, and the water flow generated by the rising force of the bubble and the bursting of the bubble exerts an external force on the removed object. give. With this external force, the filtration capacity of the second filter membrane 21 is constantly refreshed and maintained at a substantially constant value.

  A feature of the present invention is that the filtration capacity is always maintained by using the bubble generation device shown in FIGS. 1 and 2. That is, even if clogging occurs in the second filter membrane 21 and the filtration capacity thereof decreases, by applying an external force that moves an object to be removed that constitutes the second filter membrane 21 like the bubble, The to-be-removed object which comprises the 2 filter membranes 21 can be moved to the waste_water | drain side, and a filtration capability can be maintained over a long term.

  As a method of moving the object to be removed, as shown in FIG. 1 (A), at the lower part of the plurality of filters 4 installed in the raw water tank 1, for example, three air diffusers 26, 27, 28 is installed. The three diffuser tubes 26, 27, and 28 are connected at both ends, and further connected to a single tube 29, which is connected to the blower 6. Holes 31 (see FIG. 2A) are formed at appropriate intervals in the lower portions of the three air diffusers 26, 27, and 28 so that air bubbles can be generated evenly in a large number of filters 4. ing. Therefore, since the air is always sent to the three air diffusers 26, 27, and 28 from both ends at a constant pressure, the plurality of filters 4 located at arbitrary locations in the raw water tank 1 are Air bubbles can be generated uniformly. And since the uniformity of this bubble can be visually confirmed from the raw | natural water tank 1, it can adjust each time.

  Here, although the hole 31 is formed in the lower part of the diffuser tubes 26, 27, and 28, as described above, the object to be removed such as metal, inorganic substance, or organic substance is mixed in the raw water 3. Therefore, by forming the hole 31 in the lower part of the diffuser tubes 26, 27, 28, an object to be removed can be deposited on the diffuser tubes 26, 27, 28 and clogging of the diffuser tubes 26, 27, 28 can be prevented. . Further, the position of the hole 31 is not limited to the bottom of the air diffuser, and may be a position where an object to be removed does not accumulate in the air diffuser.

  The three air diffusers 26, 27, and 28 are formed to extend in a direction perpendicular to the filter 4. By being in this positional relationship, the plurality of filters 4 can be dealt with with a small number of air diffusers, so that the filtering device itself can also have a simplified structure. Moreover, in order to install the filters 4 at equal intervals on both inner walls in the long side direction of the raw water tank 1, filter holders 25 are formed corresponding to the number of filters. The filter holder 25 facilitates the installation and removal of the filter 4, and the distance between the filters 4 described later can be accurately maintained. Further, as shown in FIG. 1B, a cradle 30 is formed on the inner wall of the raw water tank 1 at a position indicated by a dotted line 30 so that the position of the filter 4 in the depth direction can also be fixed. Accordingly, the filters 4 can be easily installed at the target positions even between the filters 4 and in the depth direction.

  Furthermore, as a feature of the method of moving the object to be removed according to the present invention, as shown in FIG. 2 (B), the bubble generated from the air diffuser 27 is larger than the distance between the filters 4 installed in the raw water tank 1. The diameter is larger.

  Specifically, the bubbles 32 generated from the holes 31 of the air diffuser 27 form a sphere having a diameter a, for example, in the raw water 3. And the bubble 32 floats to the raw | natural water 3 surface, but passes between the filters 4 of the space | interval b, for example in the middle. At this time, in the present invention, since the relationship between the two is set to be a> b, the bubble 32 passes between the filters 4 at a distance b while being deformed as indicated by 33. As a result, the bubbles 33 can apply an external force to the second filter film 21 reliably and uniformly.

  As a result, in the fluid removal object removal method of the present invention, the removal of the removal object forming the second filter film 21 that is the cause of clogging is released by the external force generated by the bubbles 32, and the constant filtration is always performed. Ability can be maintained. This seems to make the thickness of the second filter 21 almost constant by applying an external force. And as if each object to be removed is plugged at the entrance of the raw water 3, the plug is removed by external force, the raw water 3 enters from the removed place, and once the plug is formed, repeat the removal by external force again It's like going. The above has the merit that the filtration capacity can be always maintained by adjusting the size of the bubbles, the amount thereof, and the time for which the bubbles are applied.

  Furthermore, as a feature of the method of moving the object to be removed according to the present invention, the amount of bubbles when the filtration device is turned on is made smaller than the amount of bubbles when continuously performing the filtration.

  Specifically, for example, for the first 3 to 5 minutes after the filtration device is turned on, bubbles of 1 liter / min are generated per filter, and thereafter, for example, per filter, as usual. To generate 2 l / min bubbles. By this method, the following effects can be obtained.

  Since the filter 4 is immersed in the raw water 3 even when the filtering device is OFF, the second filter film 21 formed on the surface of the filter 4 is also immersed in the raw water 3. Therefore, the membrane composition of the second filter membrane 21 is clearly loosely formed by the raw water 3 compared to when the filtration device is ON. In this state, for example, if bubbles of 2 liters / minute are generated per filter as usual, the object to be removed from the surface of the second filter film 21 is moved again into the fluid. As a result, even if the second filter film 21 is completely removed or remains, a necessary minimum film thickness cannot be obtained, and the filtering ability of the filter 4 is greatly reduced. And if it filters in this state, a lot of to-be-removed objects will mix in the filtration fluid.

  Therefore, by operating the filtration device according to the method of the present invention, the second filter membrane 21 when the filtration device is turned on is not destroyed, and the normal second filter membrane 21 is brought into an early state. Therefore, the filter 4 can be maintained over a long period of time without degrading the filtering ability.

  In addition, as long as the filtration capability can be maintained, an external force may be applied constantly or intermittently. Further, in the above-described embodiment of the present invention, the case where there are three diffusing tubes has been described, but there is no need to be particularly limited, and it is desirable to consider according to the work purpose. In addition, various modifications can be made without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS (A) Top view explaining the to-be-removed material removal apparatus of this invention, (B) It is sectional drawing of the XX direction in (A). It is (A) sectional drawing and (B) sectional drawing explaining the to-be-removed thing removal method of the fluid of this invention. It is a figure explaining the 1st and 2nd filter film | membrane of this invention. It is a figure explaining the 1st and 2nd filter film | membrane of this invention. It is a figure explaining this invention and the conventional filtration apparatus. It is (A) perspective view and (B) perspective view explaining this invention and the conventional filter. It is a figure explaining the 1st and 2nd filter membrane of the present invention and the conventional.

Claims (6)

In the fluid removal object removal method of removing the removal object by immersing a plurality of filters in the fluid containing the removal object and passing the fluid through the filter,
A method of removing an object to be removed of fluid, wherein bubbles generated from below the filter pass between the filters while reducing the shape of the filter by narrowing the interval between the filters. The fluid removal object removal method according to claim 1, wherein the bubble is deformed by the filter, and an external force is applied to a surface of the filter by a resistance against the deformation of the bubble. In the fluid removal object removing apparatus for filtering the fluid by immersing a plurality of filters in the fluid containing the removal object,
An apparatus for removing an object to be removed of fluid, wherein the filter is arranged at a substantially predetermined interval b, and the interval b is set so that bubbles passing between the filters are deformed. The fluid removal object removing device according to claim 3, wherein the bubble generating device provided below the filter is disposed so as to be orthogonal to the filter surface. By immersing a plurality of filters in the fluid generated when machining the ingot into a wafer, and passing the fluid through the filter, the object to be removed generated by the machining is removed and filtered. In a method of manufacturing a wafer that reuses fluid,
A method of manufacturing a wafer, characterized in that, by narrowing the interval between the filters, bubbles generated from below the filters pass between the filters while deforming their shapes. A plurality of filters are immersed in a fluid generated when machining a semiconductor wafer, and the fluid is allowed to pass through the filter to remove an object to be removed generated by the machining. In a manufacturing method of a semiconductor device to be reused,
By narrowing the interval between the filters, bubbles generated from below the filters pass between the filters while deforming their shapes.