JP2013169620A - Magnet strainer and polishing device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet strainer for use in a substrate polishing device capable of easily checking foreign matter magnetized and attached inside the magnet strainer.SOLUTION: When a glass substrate is polished by a polishing machine by using polishing slurry circulated and supplied from a polishing slurry tank, a magnet strainer 1 is provided in a polishing slurry circulation path. The magnet strainer 1 includes a transparent strainer pipe 2, and a plurality of magnets 3 fixed to a disk 4. The disk 4 is rotated by a rotation means 5, and the magnets 3 generate an alternating magnetic field. In the alternating magnetic field, magnetic foreign matter in the polishing slurry flowing through the strainer pipe 2 is attached to an inside wall of the strainer pipe 2. The magnetic foreign matter attached to the inside wall of the strainer pipe 2 is washed away with water.

Description

  The present invention relates to a magnetic strainer used for processing a working fluid (coolant) used in a polishing apparatus for polishing a glass substrate or the like, and a polishing apparatus using the same. More specifically, the present invention relates to a magnetic disk substrate, a magnetic strainer used for processing a processing liquid (coolant) used in a polishing apparatus for polishing a flat substrate such as a magnetic disk, and a polishing apparatus using the same.

  For manufacturing semiconductor devices and liquid crystal screens, polishing of glass, quartz, and silicon wafers, which are the materials, is an important technology. In particular, a polishing technique for polishing a glass substrate made of quartz glass is widely used industrially including the manufacture of magnetic disk devices. In polishing quartz glass, a polishing pad is applied to the surface of the glass substrate, and a polishing slurry containing an abrasive such as cerium oxide is supplied between the polishing pad and the substrate, and the surface of the glass substrate is rubbed with the polishing pad. While polishing. This polishing slurry is a polishing liquid containing abrasive grains.

  When polishing with the polishing slurry as described above, the surface of the glass substrate may be damaged due to foreign matter contained therein, foreign matter attached to the glass surface, or foreign matter peeled off from the glass surface. The polishing slurry is a polishing liquid in which fine particles such as cerium oxide, zirconium oxide, silicon dioxide, and aluminum oxide are dispersed in water or the like. In general, a polishing slurry used in a polishing apparatus has a large viscosity. Foreign substances such as metal fine particles mixed in the polishing slurry are mainly foreign substances of magnetic material.

  The polishing slurry is generally recycled after being used for polishing, because it is expensive. At this time, since the polishing slurry is used in a closed circulation circuit, consideration is given to prevent foreign matter from entering. For this reason, the magnetic material should hardly be mixed, but it may enter from the pipe or the like, and even if only a single particle is present, if foreign matter such as iron is mixed in the polishing slurry, The surface will be scratched. Such a scratched workpiece may not become a product, particularly in the field of semiconductors, and metal foreign matters in the polishing slurry are subjected to iron removal as much as possible. In view of this, a method using a magnet strainer has been proposed in order to remove magnetic foreign substances in the polishing slurry.

  For example, Patent Document 1 discloses a method for manufacturing a magnetic disk substrate for polishing a magnetic disk substrate. According to this method, a polishing slurry is circulated between a polishing apparatus and a polishing slurry tank in a circulation path. A magnet strainer is installed. The magnet strainer is a stainless steel metal tube with a magnet installed inside. When the polishing slurry passes through the magnet strainer, the metal foreign matter in the polishing slurry adheres to the magnet and is removed. This strainer device with a magnet is also disclosed in Patent Document 2 for the same purpose.

JP 2006-099944 A Utility model registration No. 3002527

  However, these magnet strainers are basically sealed containers made of stainless steel or the like, and it is difficult to visually confirm the degree of adhesion of metal foreign matter to the magnets. The operator confirms that the metal foreign matter is attached to the magnet, and if the metal foreign matter or the like adheres and becomes dirty, in order to clean it, it is necessary to periodically open and check the metal tube. For this reason, there is a need for a technique that allows easy confirmation of foreign matter adhering to the magnet in the magnet strainer and easy cleaning.

  In addition, metallic foreign substances such as magnetic substances and foreign substances such as nonmagnetic substances in the polishing slurry are often fine particles of about several μm or less. In particular, the metal magnetic material in this is harmful to the polishing process and needs to be removed. However, when the particle size of the metal magnetic material becomes fine particles of the order of μm or less, the magnetic force is weak, and the magnetic slurry may not be sufficiently adsorbed by the strength of the flow of the polishing slurry. In other words, depending on the viscosity of the polishing slurry, the distance from the magnet surface, and the like, it may not be possible to capture only with the static magnetic field of the magnet.

The present invention has been made based on the technical background as described above, and achieves the following objects.
An object of the present invention is to provide a magnet strainer for removing magnetic foreign substances in a polishing slurry and a polishing apparatus using the same.
Another object of the present invention is to use a magnetic strainer for effectively capturing metal fine particles from a polishing slurry by utilizing magnetic precipitation of magnetic fine particles by a magnet and magnetic field swinging force by rotation of a magnet unit. It is to provide a polishing apparatus used.

In order to achieve the above object, the present invention employs the following means.
The present invention provides a magnet strainer used in a polishing apparatus for polishing a surface to be polished using a polishing slurry, and a polishing apparatus using the same.

The magnet strainer of the present invention is
In a magnet strainer used in a polishing apparatus for polishing a surface to be polished using a polishing slurry,
The magnet strainer is
A magnet strainer pipe for passing the polishing slurry, made of a transparent material, and installed on a flat first surface;
A magnet rotor composed of a plurality of magnets disposed on a second surface that is flat and opposed to the first surface on which the magnet strainer pipe is installed;
A rotation drive means coupled to the magnet rotor and configured to rotate the magnet rotor;
When the polishing slurry flows through the magnet strainer pipe, the magnetic metal contained in the polishing slurry is adsorbed by the rotating magnet and attached to the inner wall of the magnet strainer pipe.

The transparent material constituting the magnet strainer pipe may be quartz. The magnet strainer pipe may be installed spirally on the first surface. As for the direction of the spiral, the flow direction of the polishing slurry flowing through the magnet strainer pipe and the rotation direction of the magnet are preferably opposite to each other.
In order to adjust the magnitude of the magnetic force passing through the magnet strainer pipe, a distance control means for changing the space interval between the magnet strainer pipe and the magnet rotor and controlling the strength of the magnetic field of the magnet is provided. What you have is good.

The polishing apparatus of the present invention is the polishing apparatus using the magnet strainer,
The polishing apparatus includes:
The magnet strainer;
A polishing slurry tank for temporarily storing the polishing slurry;
A polishing machine for polishing the surface to be polished using the polishing slurry;
It consists of pipes for transporting the polishing slurry between the polishing slurry tank and the magnet strainer, between the magnet strainer and the polishing machine, and between the polishing machine and the polishing slurry tank, respectively.
The polishing slurry circulates in a closed circulation path including the polishing slurry tank, the magnet strainer, the polishing machine, and the magnet strainer pipe.

According to the magnet strainer of the present invention and the polishing apparatus using the same, the following effects can be obtained.
Since the magnet strainer according to the present invention is made of a transparent material, it is possible to easily check the adhered foreign metal, and it is possible to easily determine the time for replacement or cleaning.
The magnet strainer of the present invention has an effect of modifying water by magnetism.

FIG. 1 is a conceptual diagram illustrating an outline of a magnet strainer 1 according to a first embodiment of the present invention. FIG. 2 is a schematic diagram illustrating an arrangement example of the strainer pipe 2 according to the first embodiment of this invention. FIG. 3 is a schematic view illustrating the arrangement of the magnets 3 according to the first embodiment of this invention. FIG. 4 is a block diagram showing an outline of a polishing apparatus 100 using the magnet strainer 1 according to the embodiment of the present invention. FIG. 5 is a conceptual diagram illustrating an outline of the magnet strainer 1 having the clearance adjusting means 11. FIG. 6 is a schematic view illustrating an arrangement example of the magnet 30 of the present invention.

[Magnet strainer]
An embodiment of a magnet strainer 1 of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram showing the structure of the magnet strainer 1. FIG. 2 is a conceptual diagram showing an arrangement example of the strainer pipe 2 of the magnet strainer 1. FIG. 3 is a conceptual diagram illustrating an arrangement example of the magnets 3 of the magnet strainer 1. The magnet strainer 1 is used for a polishing apparatus for polishing a surface to be polished such as a glass substrate using a polishing slurry, and is for removing magnetic substances in the polishing slurry.

  The magnet strainer 1 is composed of a strainer pipe 2 for allowing polishing slurry to pass through, a magnet 3 fixed on the disk 4, and a rotation drive means 5 for rotating the disk 4. In the present embodiment, the magnet 3 is fixed to one side of the side surface of the disc 4. In this example, the magnet 3 including the disk 4 and the like is referred to as a magnet rotor 6 because an alternating magnetic field is generated by rotating the integrated disk 4 and magnet 3. The rotation drive means 5 rotates the magnet rotor 6 fixed to the rotation shaft 7 which is the output shaft.

  As the rotation driving means 5, any rotation driving means can be used as long as it rotates the magnet rotor 6, but a general-purpose electric motor is used in the present embodiment. The rotating shaft 7 is integrally fixed with the rotor of the motor and is an output shaft. The rotating shaft 7 is connected to a shaft 8 fixed at the center of the disc 4 by connecting means 9 which is a known joint. For example, the connecting means 9 may be screwed or fixed with a key. Alternatively, the disk 4 and the rotating shaft 7 are connected to each other by a spline in which a plurality of key grooves are arranged at equal intervals on the peripheral surface of an inner hole opened in the center of the disk 4. May be fixed directly.

  Thereby, when the rotor of the motor is driven to rotate, the disk 4 is driven to rotate. The rotating shaft 7 is connected to the output shaft of the rotation driving means 5. The rotary shaft 7 transmits the rotational power of the rotary drive means 5 to the disc 4. The disk 4 is roughly a circular plate shape, and its center is fixed to the rotating shaft 7 and is driven to rotate. As shown in FIG. 3, the disc 4 is composed of a plurality of magnets 3 fixedly disposed on one side surface thereof. The magnet 3 is a magnet for adsorbing the magnetic metal in the polishing slurry, and includes a plurality of magnet elements (not shown).

  A surface including one side surface of the disc 4 is fixed to the rotating shaft 7 so as to be orthogonal to the central axis direction of the rotating shaft 7. A housing 10 having a strainer pipe 2 is disposed opposite to the disc 4. The strainer pipe 2 is arranged in a spiral shape in a surface parallel to one side surface of the disc 4 and in the housing 10. That is, the strainer pipe 2 is disposed in a spiral shape (spiral shape) in one plane in the housing 10. The housing | casing 10 is arrange | positioned facing the disk 4, and a rough shape is a disk-shaped shape. That is, one surface (front surface) of the housing 10 is arranged in parallel with the disc 4.

  In the present embodiment, as shown in FIG. 2, the strainer pipe 2 is arranged in a plane in the housing 10 so as to spiral, that is, spiral. The surface on which the strainer pipe 2 is disposed is parallel to the surface of the disc 4. Therefore, the surface on which the strainer pipe 2 is installed is parallel to the surface on which the magnet 3 is installed. Precisely, the disc 4 to which the magnet 3 is fixed and the strainer pipe 2 are arranged in parallel to face each other with a space therebetween.

  FIG. 3 is a conceptual diagram showing an example of the arrangement of the magnets 3 on the disk 4 and shows a state in which the disk 4 is viewed from the strainer pipe 2 side. In the example illustrated in FIG. 3, the magnet 3 has a short cylindrical shape. The cylindrical center line is fixedly disposed on the disk 4 so as to be parallel to the center line of the disk 4. The magnetic poles of these magnets 3 are arranged in a direction perpendicular to the center line of the strainer pipe 2. Another example of a magnet is illustrated in FIG. Each of the magnets 30 shown in FIG. 6 has a rectangular shape with a long and narrow shape.

  The magnet 30 has the same function as the magnet 3 illustrated in FIG. These magnets 30 are arranged on the side surface of the disk 4 so that the longitudinal axis thereof intersects the rotation center axis of the shaft 8. The magnetic pole of the magnet 30 is disposed so as to face the strainer pipe 2. The strainer pipe 2 is held and fixed to the housing 10. The strainer pipe 2 is a fluid pipe having an inner hole and a predetermined diameter. Although the thickness of the strainer pipe 2 can be set arbitrarily depending on the amount of use of the polishing slurry, the flow rate, etc., it is practically preferably 15 cm to 50 cm.

  FIG. 2 illustrates an arrangement example of the strainer pipe 2. The strainer pipe 2 is disposed in the same plane in a spiral shape. As shown in FIG. 2, the strainer pipe 2 is arranged in a spiral shape with a center point at a point where the axis of the rotary shaft 7 intersects the plane including the strainer pipe 2. When the polishing slurry flows through and passes through the strainer pipe 2, foreign substances such as magnetic metal contained in the polishing slurry are adsorbed by the rotating magnet 3 and attached (trapped) to the inner wall of the strainer pipe 2.

  The strainer pipe 2 passes the polishing slurry, and the polishing slurry discharged therefrom is supplied to a polishing machine. The strainer pipe 2 has a water inlet 2 a for supplying polishing slurry into the strainer pipe 2 and a water outlet 2 b for discharging the polishing slurry in the strainer pipe 2. The water inlet 2a and the water outlet 2b are connected to the strainer pipe 2 by a known pipe connecting method. For example, the water inlet 2a and the water outlet 2b are connected to the strainer pipe 2 by welding, a pipe joint or the like.

  Alternatively, the water inlet 2a and the water outlet 2b may be integrated with the strainer pipe 2 without using a connection structure. The polishing slurry is injected from the water inlet 2a, and the polishing slurry flows through the strainer pipe 2 and is discharged from the water outlet 2c. When the polishing slurry flows through the strainer pipe 2, it flows in an alternating magnetic field generated from the rotating magnet 3. While the polishing slurry flows through the strainer pipe 2, the magnetic material such as iron contained in the polishing slurry is detached from the main flow of the polishing slurry and adheres to the wall surface of the strainer pipe 2.

  The distance between the magnet 3 and the strainer pipe 2 is practically that the magnet 3 rotates in the vicinity of the surface of the strainer pipe 2 to generate an alternating magnetic field, which affects the magnetic material in the polishing slurry and moves it. It is necessary to make it. Since the distance that the magnet 3 can rotate must be secured, the distance between the magnet 3 and the strainer pipe 2 is practically 1 mm or more in consideration of the assembly of the strainer pipe 2 and the ease of mechanical adjustment. Preferably, it is 3 mm or more. As shown in FIG. 5, the direction of the polishing slurry flowing through the strainer pipe 2 and the direction of rotation of the magnet 3 (direction in which the magnetic force changes) are opposed to each other (facing each other).

  In other words, in the example of FIG. 5, the polishing slurry flows through the strainer pipe 2, and its rotation is clockwise when viewed from the top of FIG. 5, and the rotation of the disk 4 and the magnet 3 is counterclockwise. It has become. The magnetic material attached to the inner wall of the strainer pipe 2 is magnetized by the magnetic field of the magnet 3, and the magnetic poles thereof are changed by the magnetic field of the magnet 3 passing therearound, and are repeated. As shown in FIG. 5, when the rotation direction of the magnet 3 and the flow direction of the polishing slurry are reversed, the magnetic material attached to the inner wall of the strainer pipe 2 moves along the inner wall of the strainer pipe 2 while repeating magnetization. This is to prevent as much as possible.

  If the rotation direction of the magnet 3 and the flow direction of the polishing slurry are used in the same direction for a long time, the magnetic substance attached to the inner wall of the strainer pipe 2 may be carried to the vicinity of the outlet of the strainer pipe 2. In this embodiment, since a general-purpose neodymium magnet is used for the magnet 3, the optimum value of the distance between the magnet 3 and the strainer pipe 2 is several millimeters to several centimeters. Moreover, in order to increase the strength of the magnetic force and the iron removal efficiency, a structure capable of adjusting the rotation speed and clearance is preferable. Adjustment of the distance between the strainer pipe 2 and the magnet 3 is referred to as clearance adjustment in the present embodiment, and this will be described in detail in the description of FIG.

The rotational speed of the magnet 3, in other words, the rotational speed of the disk 4 depends on the required magnetic force, but several tens to several hundreds of revolutions per minute is practical. In one example, a rotational speed of 50 to 250 per minute is practical.
[Material of strainer pipe 2]
The strainer pipe 2 is preferably made of an arbitrary transparent material so that the inside thereof can be seen from the outside. Of course, the material of the strainer pipe 2 does not affect the polishing slurry, does not cause a chemical reaction with the polishing slurry, and needs to withstand the pressure when supplying and discharging the polishing slurry.

  Any known material can be used as long as the strainer pipe 2 has a function of visually observing a metal or the like adhering to its inner wall. Examples of such materials include glass, transparent acrylic resin such as polymethyl methacrylate resin (PMMA), polycarbonate resin (PC), polyphenylene sulfide (PPS), polybutylene terephthalate resin (PBT), and polyvinyl chloride (PVC). Etc. However, the material of the strainer pipe 2 is selected depending on the type of polishing slurry.

  For example, since the polishing slurry is usually an aqueous solution and does not require much pressure in the strainer pipe 2, a resin material such as PC or acrylic resin can be used. When the polishing slurry is acidic, a material such as PVC that can withstand acidity is preferable. The material of the strainer pipe 2 is preferably a material with good workability in order to change the shape of the magnet strainer container and to join other parts. The strainer pipe 2 is manufactured by any known manufacturing method. In the present embodiment, the strainer pipe 2 is made of transparent quartz.

Quartz is characterized by its ability to withstand polishing fluids that are water-soluble or acidic and withstand large fluid pressures. Therefore, the quartz strainer pipe 2 is preferably transparent to visible light, but may be made of a material that is transparent to some frequencies of visible light.
[Magnet structure and type]
The type and shape of the magnet 3 are not particularly limited. For example, a magnet such as neodymium, ferrite, rare earth cobalt, and permalloy can be used.

  In particular, the magnet 3 is preferably a neodymium permanent magnet mainly composed of neodymium, iron, boron or the like. The magnet 3 can be of any shape, but in consideration of cost and the like, a cylindrical magnet as shown in FIG. 3 or a rectangular magnet as shown in FIG. 6 is preferable. For example, a rectangular magnet has dimensions of 50 mm in length, 25 mm in width, and 30 mm in height. The magnet is drilled at a predetermined distance from the left and right ends, for example, 15 mm, and is fixed to the disk 4 with screws through the holes. The surface of the magnet is preferably plated with nickel to prevent rust.

  The magnet 3 can fix an arbitrary number of magnets to the disc 4 as necessary, but in order to make the generated magnetic field symmetrical, a combination of an even number is preferable. In the arrangement example shown in FIGS. 3 and 6, eight magnets are arranged around the center of the disk 4. When arranged in this way, adjacent magnets 3 are arranged so that the same poles face each other and are arranged so that the magnetic lines of force are repelled, and the number of magnetic lines passing through the strainer pipe 2 is efficiently increased. The size of the magnet 3 is manufactured and designed by selecting a permeance coefficient with a large maximum energy product in consideration of the aspect ratio (vertical × horizontal × width).

  The magnet 3 is preferably arranged so as to cover all the strainer pipes 2 arranged in a spiral shape. In other words, it is preferable that the plurality of magnets 3 are arranged so as to cross over the strainer pipe 2 arranged in a spiral shape and pass through the entire surface while rotating. Therefore, the disc 4 to which the magnet 3 is attached has the same dimension as the outermost large diameter of the strainer pipe 2 arranged in a spiral shape or a dimension larger than that. In the present embodiment, since the outermost large diameter of the strainer pipe 2 arranged in a spiral shape is 200 mm to 250 mm, the disk 4 has a large diameter of 200 mm to 300 mm.

  With such a structure, the magnetic poles of the adjacent magnet elements repel each other, generating a strong magnetic field around the magnet 3, and this part has a strong magnetic field. Therefore, a large magnetic field is applied to magnetic particles such as stainless steel fragments and iron pieces. Can be given. This is a difference between the magnetic gradient and the magnetic gradient, and the combination of different poles increases the magnetic gradient, which is a contrivance to make it difficult to separate the supplemented magnetic body. The magnet 10 is fixed to the disc 4 by an arbitrary fixing means. In the present embodiment, the magnet 10 is fixed by a screw (not shown).

[Cleaning the strainer pipe]
When the amount of magnetic material attached to the inner wall of the strainer pipe 2 reaches a certain amount, it is necessary to clean the inside of the strainer pipe 2 and discharge the attached magnetic material. The magnetic substance attached (captured) to the inner wall of the strainer pipe 2 can be seen from the outside of the state of the inner wall of the strainer pipe 2. Foreign substances such as iron adhering to the inner wall of the strainer pipe 2 can be easily seen with the naked eye when they are large in size, such as submillimeter order or millimeter order.

  Since it is used for circulating polishing slurries, most of the foreign matters are fine particles of the order of micrometers or smaller. Therefore, such foreign matter is such that the strainer pipe 2 is slightly changed in color. The magnetic foreign matter mixed in the polishing slurry is in the order of μm, so it is difficult to see each single particle. However, a large amount of magnetic fine particles adhere to the inner wall of the strainer pipe 2 and the magnetic particles adhering to the inner wall. When the body fine particles are peeled off and back-contaminated again into the polishing slurry, or approaching such a state, the color of the strainer pipe 2 appears to change.

  As described above, when the amount of the magnetic material attached to the inner wall of the strainer pipe 2 reaches a certain amount, the magnet 3 is separated from the strainer pipe 2 and cleaned. In the present embodiment, cleaning of the strainer pipe 2 employs a water-washing type. Specifically, cleaning water such as pure water is pumped into the strainer pipe 2 to clean the inner wall of the strainer pipe 2. When cleaning the foreign matter adsorbed on the inner wall of the strainer pipe 2, first, the magnet rotor 6 is separated from the strainer pipe 2 to weaken the magnetic force inside the strainer pipe 2.

  At this time, the distance between the strainer pipe 2 and the magnet 3 is separated to such an extent that the influence on the strainer pipe 2 is weakened or eliminated by the magnetic force of the magnet 3. In the case of a general-purpose magnet used in this embodiment, if this distance is 50 mm or more, the influence of the magnetic field of the magnet 3 on the strainer pipe 2 is substantially reduced, which is effective. As shown in FIG. 2, there are three-way valves 12 and 13 at the inlet 2 a and the outlet 2 b of the strainer pipe 2, and both the three-way valves 12 and 13 are switched to switch between the cleaning water and the polishing slurry.

  The three-way valve 12 switches between the inlet 2a and the cleaning water inlet 14. The three-way valve 12 switches between the outlet 2b and the washing water outlet 15. Cleaning water is pumped from the cleaning water inlet 14 into the strainer pipe 2 by cleaning water pumping means such as a pump 16 to clean the inner wall of the strainer pipe 2. In this manner, the cleaning water is discharged from the cleaning water outlet 15 by cleaning foreign matter such as iron powder adhering to the inner wall while flowing through the strainer pipe 2.

[Polishing equipment]
FIG. 4 schematically shows a system of a polishing apparatus 100 using the magnet strainer 1 of the present invention. The polishing apparatus 100 includes a polishing machine 101, a polishing slurry tank 102, a magnetic strainer 1, and a pipe for flowing and transferring polishing slurry between these apparatuses. These pipes are indicated by solid lines in FIG. 4, and the flow direction of the polishing slurry in the closed circulation path is indicated by arrows.

  The pipe constitutes a circulation circuit that transports and circulates the polishing slurry between the polishing slurry tank 102 and the magnet strainer 1, between the magnet strainer 1 and the polishing machine 101, and between the polishing machine 101 and the polishing slurry tank 102. The polishing slurry tank 102, the magnet strainer 1, the polishing machine 101, and these pipes constitute a closed circulation path, and the polishing slurry circulates in this closed circulation path. Of course, although not shown, other devices such as a pump for forcibly circulating the polishing slurry are also arranged in this closed circulation path.

  As illustrated in FIG. 4, the polishing slurry is circulated and reused in the order of the polishing machine 101, the polishing slurry tank 102, the magnet strainer 1, and the polishing machine 101. The polishing slurry tank 102 temporarily stores the polishing slurry discharged by being used for polishing by the polishing machine 101. The polishing machine 101 polishes the surface to be polished such as a glass substrate (not shown) using the polishing slurry supplied from the polishing slurry tank 102. Thereafter, the polishing slurry used for polishing is returned to the polishing slurry tank 102 again.

  In this example, the magnet strainer 1 is installed in a circulation path between the polishing slurry tank 102 and the polishing apparatus 101. However, as long as it is within the closed circulation path of the polishing slurry, the magnet strainer 1 is placed at any position in the circulation path. May be installed. By installing the magnet strainer 1, when the polishing slurry passes through the magnet strainer 1, metal foreign matters such as iron in the polishing slurry adhere to the inner wall of the strainer pipe 2 and are removed. The polishing machine 101 polishes the surface to be polished while automatically controlling a polishing pad (not shown).

  At this time, the polishing machine 101 performs polishing while supplying polishing slurry between the surface to be polished and the polishing pad. Examples of the surface to be polished include a quartz glass substrate. As the glass substrate, it can be used for polishing amorphous, chemically strengthened or crystallized glass that is usually used as a magnetic disk substrate, for example, glass of soda lime, aluminosilicate, lithium silicate, lithium aluminosilicate, aluminoborosilicate, etc. Is mentioned. The polishing slurry uses a liquid that is optimal for polishing depending on the material of the surface to be polished.

  For example, a cerium oxide-based abrasive is preferable for polishing a glass substrate. The polishing pad, the polishing slurry, the polishing machine 101, the polishing slurry tank 102 and the like are not the main purpose of the present invention, and thus detailed description thereof is omitted. When the magnetic strainer 1 of the present invention is used, the strainer pipe 2 is transparent, so that the cleaning time can be easily confirmed and estimated. Therefore, unlike the conventional magnet strainer, it is not necessary to replace or clean it when cleaning is unnecessary, and the working efficiency of the polishing apparatus 100 is improved. Eventually, polishing costs can be reduced.

  The polishing machine 101 polishes the surface to be polished using a polishing slurry, and this polishing means lapping or polishing. The polishing slurry is a polishing liquid in which fine particles such as cerium oxide, zirconium oxide, silicon dioxide, and aluminum oxide are dispersed in water or the like. In particular, in polishing a glass substrate, the polishing slurry using cerium oxide is polished. Fast and desirable.

[Clearance adjustment means 11]
As shown in FIG. 5, the magnet strainer 1 has a clearance adjusting means 11 that adjusts the distance between the strainer pipe 2 and the magnet 3. The clearance adjusting means 11 includes a ball screw 11a for moving the strainer pipe 2, a stepping motor 11b connected to the ball screw 11a via a joint, and a nut fixed to the housing 10 where the strainer pipe 2 is disposed and fixed. 11c and the like.

  The stepping motor 11b is driven to rotate the ball screw 11a. The stepping motor 11b and the rotation driving means 5 are fixedly disposed on the main body (not shown) of the magnet strainer 1. When the ball screw 11a is rotated, the nut 11c screwed into the ball screw 11a is driven in a linear direction. For this purpose, the strainer pipe 2 fixed to the nut 11c moves. The housing 10 is guided in a linear direction by a guide guide (not shown). In FIG. 5, the moving direction of the strainer pipe 2 is indicated by an arrow.

  The clearance adjusting means 11 moves the strainer pipe 2 to appropriately adjust the movement amount or position of the strainer pipe 2 and controls the strength of the magnetic field of the magnet 3. In the present embodiment, the nut 11 c of the clearance adjusting means 11 is fixed to the housing 10 storing the strainer pipe 2, and the clearance adjusting means 11 adjusts the clearance while moving the housing 10. As another example, the nut 11c of the clearance adjusting means 11 is fixed to the rotation driving means 5 or a housing (not shown) on which the rotation driving means 5 is mounted, and the clearance adjusting means 11 moves the disc 4 together with the rotation driving means 5. The clearance adjustment can be performed while moving, but detailed description thereof is omitted.

  For the clearance adjustment, a mechanical mechanism that manually separates the strainer pipe 2 from the magnet 3 or the magnet 3 from the strainer pipe 2 can be adopted without using the stepping motor 11b. Is omitted. The strainer pipes 2 are spirally arranged in the casing 10 in a plane, but are not limited to this arrangement structure, and may be arranged in a meandering manner or in a straight line. As described above, it may be arranged in multiple layers. Therefore, in the present invention, the planar arrangement of the strainer pipe 2 is not a single plane but a concept including these.

  The magnet strainer of the present invention is preferably used in the fields of semiconductor device manufacture and liquid crystal screen manufacture, particularly in the polishing field of glass, quartz, silicon wafers and the like.

DESCRIPTION OF SYMBOLS 1 ... Magnet strainer 2 ... Strainer pipe 3 ... Magnet 4 ... Disk 5 ... Rotation drive means 6 ... Magnet rotor 7 ... Rotating shaft 8 ... Shaft 9 ... Connection means 10 ... Case 11 ... Clearance adjustment means 12, 13 ... Three-way valve DESCRIPTION OF SYMBOLS 14 ... Washing water inlet 15 ... Washing water outlet 16 ... Pump 30 ... Magnet 100 ... Polishing apparatus 101 ... Polishing machine 102 ... Polishing slurry tank

Claims (6)

In a magnet strainer used in a polishing apparatus for polishing a surface to be polished using a polishing slurry,
The magnet strainer is
A magnet strainer pipe for passing the polishing slurry, made of a transparent material, and installed on a flat first surface;
A magnet rotor composed of a plurality of magnets disposed on a second surface that is flat and opposed to the first surface on which the magnet strainer pipe is installed;
A rotation drive means coupled to the magnet rotor and configured to rotate the magnet rotor;
When the polishing slurry flows through the magnet strainer pipe, the magnetic metal contained in the polishing slurry is adsorbed by the rotating magnet and attached to the inner wall of the magnet strainer pipe. . In the magnet strainer according to claim 1,
The magnet strainer, wherein the transparent material is quartz. In the magnet strainer according to claim 1 or 2,
The magnet strainer pipe is installed on the first surface in a spiral shape. The magnet strainer. In the magnet strainer according to claim 3,
The flow direction of the said polishing slurry which flows through the said magnet strainer pipe, and the rotation direction of the said magnet are mutually opposite directions. The magnet strainer characterized by the above-mentioned. In the magnet strainer according to claim 1 or 2,
A magnet strainer, characterized by comprising a distance control means for changing a space interval between the magnet strainer pipe and the magnet rotor and controlling the strength of the magnetic field of the magnet. The polishing apparatus using the magnet strainer according to claim 1 selected from claims 1 to 5,
The polishing apparatus includes:
The magnet strainer;
A polishing slurry tank for temporarily storing the polishing slurry;
A polishing machine for polishing the surface to be polished using the polishing slurry;
A pipe for transporting the polishing slurry between the polishing slurry tank and the magnet strainer, between the magnet strainer and the polishing machine, and between the polishing machine and the polishing slurry tank, respectively.
The polishing apparatus, wherein the polishing slurry circulates in a closed circulation path including the polishing slurry tank, the magnet strainer, the polishing machine, and the magnet strainer pipe.

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