JP5891320B1 - Processing method using zeta potential control method - Google Patents

Abstract

An object of the present invention is to develop a new method for controlling the zeta potential of a dispersion solution. In a zeta potential control method for controlling a zeta potential of a dispersion solution in which particles are dispersed in a solvent, the present invention applies an electric field that fluctuates at a frequency of 20 Hz to 1 kHz to the dispersion solution. Provided is a zeta potential control method characterized by increasing the absolute value of a zeta potential. The present invention also provides a reaction method, a processing method, a cleaning method, a polishing method, a dispersion solution manufacturing method, a zeta potential control device, and a polishing device, to which this zeta potential control method is applied. [Selection] Figure 1

Description

  The present invention relates to a zeta potential control method for increasing the absolute value of the zeta potential of a dispersion solution by applying a varying electric field to a dispersion solution (slurry) in which particles are dispersed in a solvent, and a dispersion solution manufacturing method. The present invention relates to a reaction method in which a chemical reaction is performed by increasing a zeta potential by applying a varying electric field to a dispersion solution. The present invention relates to a treatment method in which an object is brought into contact with a dispersion solution while applying a varying electric field, and more particularly to a polishing method in which an object is brought into contact with a dispersion solution in which abrasive grains are dispersed to perform polishing. Furthermore, the present invention relates to a zeta potential control device and a polishing device having a mechanism for applying a variable electric field.

In a dispersion solution in which particles are dispersed, there is a physical quantity called “zeta potential”. “Zeta potential” is defined as the potential at the “slip surface” of the electric double layer formed around the particles in the dispersion. The “slip surface” is a surface that can be regarded as a hydrodynamic surface of the particle when the particle moves in the dispersion solution. As shown in FIG. 7A, an “ion-fixed layer” in which ions are attracted and fixed around particles whose surface is charged, and “ion” in which ions are freely diffused by thermal motion. A “slip surface” exists in the boundary region with the “diffusion layer”. When the particles are electrophoresed, the migration distance varies depending on the potential of the sliding surface (zeta potential), so that the zeta potential of the particles can be measured by electrophoresis.
Since the repulsive force between two particles increases as the absolute value of the zeta potential increases, the particles are stably dispersed in the solvent. Conversely, when the absolute value of the zeta potential is small, the repulsive force between the two particles is small, and the particles are likely to aggregate in the solvent.

  For example, red blood cells in blood are negatively charged on the surface, the absolute value of the zeta potential is large, and repulsive force acts and repels, making it difficult for them to aggregate with each other. By this action, red blood cells can smoothly pass through capillaries and carry oxygen. However, it is known that when the zeta potential of erythrocytes decreases due to physiological / physical stress or the like, erythrocytes tend to aggregate and the oxygen transport function decreases.

Thus, since the zeta potential affects the dispersion and aggregation of particles, the dispersion / aggregation of particles can be controlled by controlling the zeta potential.
For example, in the manufacturing process of many materials such as electronic materials, magnetic materials, pigment inks, ceramics, and emulsions, a dispersion solution (slurry) in which particles are dispersed in a solvent is manufactured. It is important to increase the dispersibility of the particles.
For example, when the particle surface has a proton dissociation group, the charge on the particle surface can be adjusted by adjusting the pH by addition of acid or alkali. Dispersibility can be improved.
In addition, a method has been developed in which compounds such as alcohol, glycol, amine, amino alcohol, aldehyde, organic acid, ester, ketone and nonionic surfactant are used as a zeta potential control agent to increase the dispersibility of particles in a solvent. (Patent Document 1). However, these methods all add a compound to control the zeta potential, and there is a problem that the added compound becomes an impurity. In addition, since the waste liquid pollutes the environment, there is a problem that in order to control the pH, in addition, there is a problem that the waste liquid is discarded after being subjected to a treatment to give a chemical agent.

  The present inventors have previously discovered a phenomenon in which when a fluctuating electric field having a low frequency of 10 Hz is applied to an antibody solution, the zeta potential of the antibody solution shifts to minus, and the change in zeta potential increases as the voltage increases. . However, this was considered that the antibody was dispersed and stabilized by the charge by applying an electric field (Non-patent Document 1).

As a dispersion solution (slurry) used industrially, there is an abrasive slurry in which abrasive grains are dispersed in a solvent in addition to an electronic material and the like.
The present inventors previously used abrasive slurry in which abrasive grains having electrical dielectric properties are dispersed in a solvent, and applied a low-frequency fluctuation electric field to the abrasive slurry to prevent abrasive grains from scattering. Thus, a method of concentrating abrasive grains at a position where processing pressure is applied and maintaining the orientation of the abrasive grains has been developed (Patent Documents 2 to 6).

JP-A-5-337351 JP 2000-343414 A JP 2003-117807 A JP 2003-300131 A JP 2004-249417 A JP 2008-137124 A

Ryuta Nakamura, 5 others, Proceedings of the annual meeting of the Japan Society for Precision Engineering, Proceedings of the Japan Society for Precision Engineering, published on March 1, 2014, 2014, ROMBUNNO. F09 (pages 449-450)

A conventional method for controlling the zeta potential of a dispersion in which particles are dispersed is to add a compound such as an acid, an alkali, or a zeta potential control agent to control the zeta potential, and the added compound becomes an impurity. There was a problem.
Accordingly, an object of the present invention is to develop a new method for controlling the zeta potential of a dispersion solution.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research. As a result, by applying an electric field that fluctuates at a frequency of 20 Hz to 1 kHz to a dispersion solution in which particles are dispersed, the absolute value of the zeta potential of the dispersion solution. Surprisingly, the present inventors have found that the absolute value of the zeta potential can be controlled by increasing the frequency rather than the voltage of the varying electric field, and the present invention has been completed.

The present invention relates to a first invention related to a zeta potential control method, a second invention related to a dispersion solution manufacturing method, a third invention related to a reaction method, a fourth invention related to a treatment method, and a fifth invention related to a cleaning method. An invention, a sixth invention related to a zeta potential control device, and a seventh invention related to a polishing device are provided.
The first invention is a zeta potential control method for controlling the zeta potential of the dispersed solution particles are dispersed in a solvent, relative to the direction of flow of the dispersion solution, the dispersion solution counterelectrode so electric field is applied to the vertical flow The zeta potential control method is characterized in that the absolute value of the zeta potential of the dispersion solution is increased by applying an electric field that is arranged along the line and is changed by a counter electrode at a frequency of 20 Hz to 1 kHz to the solution.
In the zeta potential control method of the first invention, a zeta potential control method of a dispersion solution in which proteins, nucleic acids, or cells are dispersed as particles can be used, and dispersion in which particles of an inorganic compound or a synthetic organic compound are dispersed as particles. It can be set as the zeta potential control method of a solution.
In the zeta potential control method described above, it is preferable to use a zeta potential control method in which the frequency of the variable electric field is 64 Hz to 800 Hz.
In the above zeta potential control method, it is preferable to increase the absolute value of the zeta potential to 40 mV or more.
Further, in the above zeta potential control method, A) the counter electrode is arranged along the flow of the dispersion solution so that the electric field is applied perpendicularly to the flow direction of the dispersion solution, and the electric field fluctuating by the counter electrode is B) a step of measuring the zeta potential of the dispersion solution to which the fluctuating electric field is applied in step A), and C) an absolute value of the zeta potential measured in step B) of the target zeta potential. If the absolute value was smaller than the viewing including the step, the city of applying a frequency variation electric field higher than the variation electric field applied in step a) the dispersion solution, the electric field varying at the frequency of 20Hz~1kHz It is preferable to use a zeta potential control method characterized by using
According to a second aspect of the present invention, in the dispersion solution manufacturing method for manufacturing a dispersion solution in which particles are dispersed in a solvent , the counter electrode is arranged along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution. It is characterized in that the dispersibility of particles in the dispersion solution is enhanced by applying an electric field that varies at a frequency of 20 Hz to 1 kHz by a counter electrode to the dispersion solution and increasing the absolute value of the zeta potential of the dispersion solution. The present invention relates to a dispersion solution manufacturing method.
In the dispersion solution manufacturing method of the second invention, it is preferable to use a dispersion solution manufacturing method in which the frequency of the variable electric field is 64 Hz to 800 Hz.
A third invention is a reaction method in which dispersed particles and other compounds or particles are chemically reacted in a dispersion solution in which particles are dispersed in a solvent, and an electric field is applied perpendicularly to the flow direction of the dispersion solution. The counter electrode is arranged along the flow of the dispersion solution as described above, and an electric field that fluctuates at a frequency of 20 Hz to 1 kHz is applied to the dispersion solution by the counter electrode, thereby increasing the absolute value of the zeta potential of the dispersion solution. It relates to a reaction method.
In the reaction method of 3rd invention, it is preferable to set it as the reaction method which made the frequency of the fluctuation | variation electric field 64 Hz-800 Hz.
According to a fourth aspect of the present invention, there is provided a processing method for processing an object by bringing the object into contact with a dispersion solution in which particles are dispersed in a solvent, so that an electric field is applied perpendicularly to the flow direction of the dispersion solution. The electrode is arranged along the flow of the dispersion solution, and an electric field that varies at a frequency of 20 Hz to 1 kHz is applied to the dispersion solution by the counter electrode , thereby increasing the absolute value of the zeta potential of the dispersion solution and processing the object. The present invention relates to a processing method characterized by this.
In the processing method of 4th invention, it is preferable to set it as the processing method which made the frequency of the fluctuation | variation electric field 64Hz-800Hz.
Moreover, in said processing method, particle | grains are abrasive grains and a processing method can be used as a grinding | polishing method. That is, it can be set as the grinding | polishing method which grind | polishes a target object by making a target object contact the dispersion solution in which particle | grains were disperse | distributed.
According to a fifth aspect of the present invention, in the cleaning method for removing impurity particles from an object by bringing the cleaning liquid into contact with the object , the counter electrode is placed in the flow of the cleaning liquid so that an electric field is applied perpendicularly to the flow direction of the cleaning liquid. By applying an electric field that is arranged along the counter electrode and fluctuates at a frequency of 20 Hz to 1 kHz to the cleaning liquid, the absolute value of the zeta potential of the impurity particles dispersed in the cleaning liquid is increased, and the impurity particles adhere to the object. It is related with the washing | cleaning method characterized by preventing.
In the cleaning method of the fifth invention, it is preferable to use a cleaning method in which the frequency of the variable electric field is 64 Hz to 800 Hz.
According to a sixth aspect of the invention, a container containing a dispersion solution in which particles are dispersed in a solvent, a tube through which the dispersion solution passes, and a flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution. The present invention relates to a zeta potential control device comprising : a counter electrode installed in the same manner; and a variable voltage application device that supplies a variable voltage having an arbitrary frequency of 20 Hz to 1 kHz to the counter electrode.
According to a seventh aspect of the present invention, there is provided a holding plate that holds a workpiece to be polished, a surface plate that contacts the workpiece held by the holding plate while applying a processing pressure while rotating, and a workpiece and a surface plate. In a polishing apparatus having an abrasive slurry supply pipe for supplying abrasive slurry between them, a counter electrode is installed along the flow of the slurry so that an electric field is applied perpendicularly to the flow direction of the slurry . The present invention relates to a polishing apparatus having a varying electric field applying device that applies a varying electric field of 64 Hz to 1 kHz to an electrode .

In the zeta potential control method of the first invention , a counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution, and the counter electrode has a frequency of 20 Hz to 1 kHz. By applying a fluctuating electric field to a dispersion solution in which particles are dispersed in a solvent, the absolute value of the zeta potential of the dispersion solution is increased. In addition, this zeta potential control method has an effect that the degree of increasing the absolute value of the zeta potential can be adjusted by adjusting the frequency of the applied variable electric field.
In the dispersion solution manufacturing method of the second invention , a counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution, and the counter electrode has a frequency of 20 Hz to 1 kHz. By applying a fluctuating electric field to the dispersion solution, the absolute value of the zeta potential of the dispersion solution is increased, and the dispersibility of the particles in the dispersion solution is enhanced. Moreover, this dispersion solution manufacturing method has an effect that the degree of dispersion of particles in the dispersion solution can be adjusted by adjusting the frequency of the applied varying electric field.
In the reaction method of the third invention , a counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution, and the counter electrode fluctuates at a frequency of 20 Hz to 1 kHz. By applying an electric field to a dispersion solution in which particles are dispersed in a solvent, the absolute value of the zeta potential of the dispersion solution is increased, so that the dispersibility of the particles is improved and the surface area of the particles involved in the reaction is increased. By increasing the charge on the particle surface that affects the reaction, the chemical reaction can be promoted.
In the treatment method of the fourth invention , a counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution, and the counter electrode fluctuates at a frequency of 20 Hz to 1 kH. An electric field is applied to a dispersion solution in which particles are dispersed in a solvent, and the object is treated with the dispersion solution with an increased absolute value of the zeta potential, so that the dispersibility of the particles is increased and the number of particles and the contact area are reduced. As the charge increases, the surface charge of the particles increases, thereby promoting chemical reaction, bonding, collision, electron donation and the like with the target object, so that the target object can be processed efficiently.
In the cleaning method of the fifth aspect of the invention , the counter electrode is installed along the flow of the cleaning liquid so that the electric field is applied perpendicularly to the flow direction of the cleaning liquid, and an electric field that fluctuates at a frequency of 20 Hz to 1 kHz by the counter electrode. Since it is applied to the cleaning liquid and the object is cleaned by this, the absolute value of the zeta potential of the impurity particles removed from the object by the cleaning liquid is increased and the impurity particles are prevented from adhering to the object again. There is an effect that the efficiency can be increased.
A zeta potential control device according to a sixth aspect of the present invention is a container that contains a dispersion solution in which particles are dispersed in a solvent, a tube that allows the dispersion solution to pass through, and an electric field that is applied perpendicular to the flow direction of the dispersion solution Since it has a counter electrode installed along the flow of the solution and a variable voltage application device that supplies a variable voltage of an arbitrary frequency of 20 Hz to 1 kHz to the electrode, the variable voltage is supplied to the electrode and electric charge is accumulated in the electrode Thus, an electric field is generated, and a varying electric field of 20 Hz to 1 kHz can be applied to the solution in the container, so that the absolute value of the zeta potential of the dispersion solution can be increased. In addition, since this zeta potential control device can supply an arbitrary fluctuating electric field of 20 Hz to 1 kHz or more to the dispersion solution, there is an effect that the degree of increasing the absolute value of the zeta potential of the dispersion solution can be adjusted.
In the polishing apparatus according to the seventh aspect of the invention , a counter electrode is installed along the flow of the slurry so that the electric field is applied perpendicularly to the flow direction of the abrasive slurry , and a variable electric field of 20 Hz to 1 kHz is generated by the counter electrode. Since it is applied, the absolute value of the zeta potential of the abrasive slurry can be increased and the dispersibility of the abrasive can be increased, so that the workpiece can be more efficiently polished.

It is a schematic diagram which shows one Embodiment of the zeta potential control method of this invention. 1A is a schematic diagram illustrating a dispersion solution in which particles are dispersed in a solvent, and FIG. 1B is a schematic diagram illustrating a state in which a varying electric field is applied to the dispersion solution. (C) is a schematic diagram showing a dispersion solution in which the absolute value of the zeta potential is increased. It is a figure which shows one Embodiment of the grinding | polishing apparatus of this invention. It is sectional drawing of the abrasive slurry supply apparatus shown in FIG. It is a graph which shows the result of having measured the relationship between the frequency of the applied fluctuation electric field, pH of an abrasive slurry, and zeta potential. It is a graph which shows the result of having measured the relationship of the frequency of the applied fluctuation electric field, the zeta potential of an abrasive slurry, and polishing amount. It is a graph which shows the result of having measured the relationship between the zeta potential of an abrasive slurry and the amount of polishing. It is a schematic diagram which shows the electric double layer formed around the particle | grains disperse | distributed in the solution, and its electric potential. FIG. 7A shows the electric double layer when the surface of the particle is negatively charged, FIG. 7B shows a graph of the potential around the particle whose surface is negatively charged, FIG. 7C shows the state of the electric double layer when two negatively charged particles approach each other.

1. Zeta potential control method of the present invention The zeta potential control method of the present invention is an absolute value of the zeta potential of a dispersion solution by applying an electric field that fluctuates at a frequency of 20 Hz to 1 kHz to a dispersion solution in which particles are dispersed in a solvent. It is a method to increase.
Here, “zeta potential” refers to the potential at the “slip surface” of the electric double layer formed around the particles in the dispersion. Details of the electric double layer and the sliding surface will be described later.
The “solvent” may be any solvent that can disperse the particles, and a polar solvent such as water or a nonpolar solvent such as silicone oil can be used.

In the present invention, the term “particle” refers to a particle having a size of 1 nm to 10,000 nm (10 μm) that can be dispersed in a solvent and charged on the surface. The particles in the present invention may have a dissociation group on the surface so that they can be charged in a solvent. In addition, the particles do not have such a dissociation group and are charged on the surface by polarization or the like. It may be capable of being tinged. The “particle” material in the present invention includes an inorganic compound, a synthetic organic compound, and a natural organic compound. Examples of the “inorganic compound” particles include, but are not limited to, particles of metals, alloys, ceramics, natural minerals, diamonds, and the like. Examples of the “synthetic organic compound” particles include, but are not limited to, plastic particles and micelles formed of amphiphilic organic compounds. In addition, the particles of the “natural organic compound” are not limited to these, and examples thereof include proteins, nucleic acids, cells, and the like.
The “particles” in the present invention may be those in which two or more of inorganic compounds, synthetic organic compounds, and natural organic compounds are mixed to form particles.

However, as the “particles” used in the present invention, it is preferable to use highly uniform inorganic compound particles or synthetic organic compound particles from the viewpoint of effectively controlling the zeta potential by applying a varying electric field.
From the viewpoint of application to medicine, the “particle” used in the present invention is preferably a protein, a nucleic acid or a cell.
In the present invention, the “dispersed solution” means a solution in which particles are mixed in a solvent, and may be a solution in which particles are completely dispersed in a solvent, or easily separated. It may be.
In the present invention, the “fluctuating electric field” refers to an electric field in which the direction and strength of the electric lines of force periodically change.

  The zeta potential control method of the present invention has an effect of increasing the absolute value of the zeta potential of a dispersion solution by applying an electric field that fluctuates at a frequency of 20 Hz to 1 kHz to a dispersion solution in which particles are dispersed in a solvent. Further, in this zeta potential control method, if the frequency of the varying electric field is further increased, the absolute value of the zeta potential can be further improved. Therefore, the absolute value of the zeta potential can be adjusted by adjusting the frequency of the varying electric field to be applied. There is an effect that it is possible to adjust the degree of increasing the.

  There are innumerable dispersion solutions used as final products or raw materials in the manufacturing process of various industrial products. Using the zeta potential, the state of the dispersion solution (dispersibility, cohesiveness) and the adsorptivity of particles to the wall surface Can be controlled. For this reason, control of the zeta potential is extremely useful for shortening the required time in the manufacturing process and ensuring long-term stability of the product.

As described above, the “zeta potential” is a potential at the “slip surface” of the electric double layer formed around the particles dispersed in the solvent. The zeta potential will be described in detail with reference to FIG. .
FIG. 7 is a schematic diagram showing an electric double layer formed around particles dispersed in a solvent and its potential. The particles dispersed in the solvent are charged positively or negatively due to the ionicity or dipole characteristics of the particles themselves. FIG. 7A shows an electric double layer in the case where the particle surface is negatively charged. Around the negatively charged particles, positive ions having a charge opposite to the surface charge are attracted and fixed, forming an “ion-fixed layer”. In addition, there is an “ion diffusion layer” around the ion fixed layer, and ions are freely diffused by thermal motion while being affected by the electric field due to the negative charge on the particle surface. When a particle moves in a solution, it does not move by itself, but moves in a form that encloses surrounding water molecules and ions. The surface that can be considered is the “slip surface”. The “slip surface” exists in the boundary region between the ion fixed layer and the ion diffusion layer.

FIG. 7B is a graph showing the potential around particles whose surface is negatively charged. The absolute value of the potential is the largest on the particle surface, and the absolute value of the potential decreases as the distance from the surface of the fine particle increases. According to this potential, positive and negative ions are present. That is, there are many positive ions near the particle surface, and the concentrations of the positive and negative ions are the same as the ion concentration of the solution at a position sufficiently far from the particle surface.
As shown in FIG. 7B, the “zeta potential” is a potential at the “slip surface” in the electric double layer. When the particles are electrophoresed, the migration distance changes depending on the surface potential (slip surface) (zeta potential) of the hydrodynamic particles. Therefore, the “zeta potential” can be measured by electrophoresis.

The zeta potential can be measured by electrophoresis, but can also be measured by other methods. For example, but not limited to these, it can also be measured by an electroacoustic method or a colloid oscillating current method.
In the electroacoustic method, when an AC voltage is applied to the slurry and the particles are vibrated to generate sound waves, solid particles with a large zeta potential move faster than solid particles with a small zeta potential and generate strong sound waves. This is a method for measuring the zeta potential from the intensity of sound waves.
In the colloidal oscillating current method, when the slurry is irradiated with ultrasonic waves, a difference in vibration occurs due to the difference in density between the solid particles and the solvent. As a result, the charge of the solid particles and the surrounding counter ions are polarized, resulting in the colloidal oscillating potential. An electric field called is generated. The colloid oscillating current method is a method for measuring the zeta potential by measuring this electric field.

By the way, in FIG. 7B, the surface of the particle is negatively charged and the periphery of the particle has a negative potential, but when the surface of the particle is positively charged, FIG. The sign of the potential is opposite to that of B), and the periphery of the particle has a positive potential. In this case, the zeta potential is also a positive value.
The absolute value of the zeta potential increases as the total charge on the particle surface increases, and the zeta potential approaches zero when the total charge on the particle surface decreases.

FIG. 7C is a schematic diagram showing the state of the electric double layer when two negatively charged particles approach each other. When two negatively charged particles approach each other, the electric double layers overlap each other, and the ion concentration becomes higher than the surroundings, so that an osmotic pressure is generated in which the solvent enters the overlapping region. This osmotic pressure is a repulsive force that separates the two particles.
Between the two particles, an attractive force due to the sum of van der Waals forces acting on the molecules constituting each particle acts, so the two particles inherently try to aggregate. However, if the two particles are charged, the repulsive force due to the osmotic pressure is generated when the two particles approach each other, and this acts as a barrier to suppress aggregation. Qualitatively, the larger the absolute value of the zeta potential, the larger the electric double layer and the greater the repulsive force between the two particles. Therefore, as the absolute value of the zeta potential increases, the particles are more stably dispersed in the solvent. Conversely, when the absolute value of the zeta potential decreases, the particles tend to aggregate in the solvent. Therefore, controlling the zeta potential is important in controlling the dispersion / aggregation of particles in the dispersion solution.

  A schematic diagram showing an embodiment of the zeta potential control method of the present invention is shown in FIG. 1A is a schematic diagram illustrating a dispersion solution in which particles are dispersed in a solvent, and FIG. 1B is a schematic diagram illustrating a state in which a varying electric field is applied to the dispersion solution. FIG. ) Is a schematic diagram showing a dispersion solution in which the absolute value of the zeta potential is increased.

As shown in FIG. 1A, when the particles (3) are dispersed in the solvent (2) filled in the container (1) to form a dispersion solution, the surfaces of the particles (3) are charged. It is in the state. In FIG. 1A, the particle (3) has a negative charge, and the zeta potential is also a negative value. And the electric double layer (4) is formed in the circumference | surroundings of particle | grains (3) with the electric charge which particle | grains take. Here, when the absolute value of the zeta potential is small, the repulsive force separating the particles (3) from each other is small, and the particles (3) are aggregated.
FIG. 1B is a schematic diagram showing a state in which a varying electric field is applied to the dispersion solution. Electrodes (5) are arranged above and below the container (1) for storing the dispersion solution, and the electrodes (5) are connected to the positive and negative terminals of the high-voltage amplifier (7) via lead wires (6). The signal generated by the function generator (8) is boosted by the high-voltage amplifier (7) and supplied to the upper and lower electrodes (5). As a result, charges are accumulated in the upper and lower electrodes (5), an electric field is generated from the electrodes (5), and the electric field is applied to the dispersion solution. Here, since the signal generated by the function generator (8) is a periodically changing signal, a periodically changing voltage signal is supplied from the high voltage amplifier (7) to the electrode (5). The strength of the electric field generated from the electrode (5) and the direction of the lines of electric force also periodically vary.

  When an electric field that varies periodically as described above is applied to the dispersion solution, the absolute value of the zeta potential of the particles (3) increases. Although the mechanism is not clear, as demonstrated in Example 1 described later, the absolute value of the zeta potential increases as the frequency of the variable electric field is increased. It is considered that the vigorous vibration leads to an improvement in the absolute value of the zeta potential of the particles (3).

When the absolute value of the zeta potential of the particle (3) increases, the number of charges (minus charge) on the surface of the particle (3) increases and the ion concentration between the particles increases, and the arrow in FIG. As shown, the osmotic pressure also increases. Due to this osmotic pressure, a repulsive force that tries to separate the particles works.
When the absolute value of the zeta potential is sufficiently increased, as shown in FIG. 1C, the particles (3) are separated from each other and the particles are more dispersed.

In the present invention, the intensity of the varying electric field applied to the dispersion solution is preferably 0.3 to 3 kv / mm, although it depends on the volume of the dispersion solution.
The frequency of the variable voltage is 20 Hz to 1 kHz. If the frequency is 20 Hz or less, it is difficult to improve the absolute value of the zeta potential to 40 mV or more, and if the frequency is 1 kHz or more, the temperature of the dispersion solution increases, which is not preferable. The frequency is preferably 32 Hz to 900 Hz, more preferably 64 Hz to 800 Hz. If the frequency is 64 Hz or more, the absolute value of the zeta potential can be made higher.

Moreover, in the zeta potential control method of the present invention, if the frequency is increased, the absolute value of the zeta potential can be further increased, so that the absolute value of the zeta potential can be controlled to a desired value by the frequency.
For example, after applying a fluctuating electric field of a specific frequency to the dispersion solution, the zeta potential of the dispersion solution is measured, and if the absolute value of the zeta potential has not reached the desired value, the frequency is further increased. By applying a varying electric field, the absolute value of the zeta potential can be brought close to a desired value.

In the present invention, a rectangular wave (square wave), a sine wave, a triangular wave, a sawtooth wave, or the like can be used as a signal for generating a fluctuating voltage, but it is preferable to use a rectangular wave having a large instantaneous change. . Further, the signal for generating the fluctuation voltage can use a waveform biased to plus, and can also use a waveform that inverts between plus and minus or a waveform biased to minus.
As shown in FIG. 1 (B), when electrodes (5) are provided above and below the dispersion solution to apply a variable electric field, the voltage signal supplied to the upper electrode and the lower electrode are supplied. It is preferable that the sign of the voltage signal is reversed. By reversing the sign in this manner, the lines of electric force always pass through the dispersion solution, so that a varying electric field can be efficiently applied to the dispersion solution. For example, it is possible to supply a voltage signal having a waveform that is biased positively to the upper electrode, and to apply a voltage signal having a waveform with an opposite sign to the lower electrode. It is also possible to supply a voltage signal having a waveform that is negatively biased to the upper electrode, and to apply a voltage signal having a waveform with the opposite sign to the lower electrode. Alternatively, a voltage signal having a waveform that reverses between plus and minus is supplied to the upper electrode, and a voltage signal having a waveform with a sign opposite to that of the voltage signal supplied to the upper electrode is supplied to the lower electrode. You can also

The time for applying the varying electric field is preferably about 5 seconds to 60 minutes, although it depends on the amount of the dispersion solution and the voltage of the varying electric field.
Further, the zeta potential control method of the present invention is not a method of forming a minute droplet and applying a varying electric field to the droplet to vibrate the droplet as described in Non-Patent Document 1, It may be a method that does not form droplets.

  The zeta potential control method of the present invention is a method that can improve the absolute value of the zeta potential of a dispersion without adding an alkali, acid, or zeta potential control agent. The zeta potential of the dispersion solution may be controlled in combination with the addition of a potential control agent.

2. Dispersion solution manufacturing method of the present invention The dispersion solution manufacturing method of the present invention is a dispersion solution manufacturing method for manufacturing a dispersion solution in which particles are dispersed in a solvent, and an electric field that varies at a frequency of 20 Hz to 1 kHz is applied to the dispersion solution. Then, the dispersibility of the particles in the dispersion solution is enhanced by increasing the absolute value of the zeta potential of the dispersion solution.

In the present invention, the “particle” means a particle having a size of 1 nm to 10000 nm (10 μm) that can be dispersed in a solvent and charged on the surface as described above, and is an inorganic compound or a synthetic organic compound. Or there are particles of natural organic compounds.
And, as described above, the “dispersion solution” in the present invention means that the particles are mixed in the solvent, and the particles may be completely dispersed in the solvent, It may be easily separated.

Dispersion solutions are industrially important. In the manufacturing process of many materials such as electronic materials, magnetic materials, pigment inks, ceramics, emulsions, biopharmaceuticals, etc., a dispersion solution (slurry) in which particles are dispersed in a solvent is used. In order to improve the performance of the material being manufactured, it is important to increase the dispersibility of the particles.
Most of the dispersion solutions used industrially are premised on the use in a state where the particles are not aggregated. For example, a pigment ink is obtained by making a pigment insoluble in a solvent into fine particles and dispersing the pigment in a solvent, and is used in an ink jet printer or the like. However, when the fine particles of the pigment of the pigment ink are aggregated, the nozzles of the ink jet printer are clogged, causing problems such as uneven printing. Therefore, it is important to increase the dispersibility of particles in industrially used dispersion solutions in order to maintain the quality for a long period of time.
In addition, there are some dispersion solutions that are used industrially, and it is important to keep the degree of dispersion constant. For example, a magnet used for an electronic component is manufactured by dispersing a magnetic metal powder in a solvent to produce a dispersion solution (slurry), applying the solution to a substrate, and sintering. Here, if the dispersibility of the dispersion solution is not constant, a difference in quality occurs in the manufactured magnet. Therefore, it is necessary to keep the dispersibility of the dispersion solution constant.

  The method for producing a dispersion solution of the present invention is characterized in that an electric field that varies at a frequency of 20 Hz to 1 kHz is applied to the dispersion solution. Thereby, the absolute value of the zeta potential of the dispersion solution is increased, and the dispersibility of the particles can be enhanced. In addition, the dispersion solution manufacturing method of the present invention can adjust the degree of dispersion of particles in the dispersion solution by adjusting the frequency of the applied varying electric field, and can also produce a dispersion solution of uniform quality. it can.

The method for increasing the absolute value of the zeta potential by applying an electric field that fluctuates at a frequency of 20 Hz to 1 kHz to the dispersion solution in the dispersion solution manufacturing method of the present invention is described in “1. Zeta potential control method of the present invention” above. The same technique can be used.
In the reaction method of the present invention, in order to further increase the absolute value of the zeta potential and further promote the chemical reaction, it is preferable to apply an electric field varying at a frequency of 64 Hz to 800 Hz to the dispersion solution.

3. Reaction method of the present invention The reaction method of the present invention is a method of chemically reacting the particles with other compounds or particles in a dispersion solution in which the particles are dispersed in a solvent, and varies at a frequency of 20 Hz to 1 kHz. By applying an electric field to the dispersion solution, the absolute value of the zeta potential of the dispersion solution is increased.
In the present invention, the “particle” means a particle having a size of 1 nm to 10000 nm (10 μm) that can be dispersed in a solvent and charged on the surface as described above, and is an inorganic compound or a synthetic organic compound. Or there are particles of natural organic compounds.
In the present invention, “compound” refers to a compound that is not “particle”, and includes an inorganic compound, a synthetic organic compound, or a natural organic compound.

In the reaction method of the present invention, “chemical reaction” means that particles dispersed in a solvent act with other compounds or particles to produce substances different from the original particles or compounds.
Examples of the “chemical reaction” include, but are not limited to, for example, a chemical reaction in which an acid is added to an aqueous solution in which starch particles are dispersed, and saccharides are produced by hydrolysis of starch, a metal that serves as a catalyst, Examples of the reaction include addition reaction, substitution reaction, elimination reaction, transfer reaction, hydrolysis, polymerization, and the like of a compound in a solution in which mineral particles are dispersed.

  The reaction method of the present invention is characterized in that an electric field that fluctuates at a frequency of 20 Hz to 1 kHz is applied to the dispersion solution. This increases the absolute value of the zeta potential of the dispersion solution, increases the dispersibility of the particles, increases the surface area of the particles involved in the reaction, and increases the charge on the particle surface that affects the reaction, There is an effect that the reaction can be promoted.

In the reaction method of the present invention, the method for increasing the absolute value of the zeta potential by applying an electric field that fluctuates at a frequency of 20 Hz to 1 kHz to the dispersion solution is described in “1. Zeta potential control method of the present invention” above. The same technique can be used.
In the reaction method of the present invention, in order to further increase the absolute value of the zeta potential and further promote the chemical reaction, it is preferable to apply an electric field varying at a frequency of 64 Hz to 800 Hz to the dispersion solution.

4). Treatment method of the present invention The treatment method of the present invention is a treatment method for treating an object by bringing the object into contact with a dispersion solution in which particles are dispersed in a solvent, and the treatment method varies at a frequency of 20 Hz to 1 kHz. By applying an electric field to the dispersion solution, the absolute value of the zeta potential of the dispersion solution is increased.
In the present invention, the “object” may be anything as long as it is larger in size than the “particles” and can be used for the treatment with the dispersion solution. “Processing” means that the composition, shape, physical and chemical properties of the object are changed by the chemical reaction, bonding, collision, and donation of electrons. To be done.

  Examples of the processing method of the present invention are not limited to these, but, for example, a polishing pad that is mechanically pressurized while contacting a workpiece with an abrasive slurry in which abrasive particles are dispersed in a solvent. And the like, and a method of performing immunostaining by bringing an antibody solution in which an antibody is dispersed in a solvent into contact with a living tissue.

  The treatment method of the present invention is characterized in that an electric field that fluctuates at a frequency of 20 Hz to 1 kHz is applied to the dispersion solution. This increases the absolute value of the zeta potential of the dispersion, increases the dispersibility of the particles, increases the number and contact area of the particles, and increases the charge on the surface of the particles, thereby increasing the chemical reaction and bonding with the object. Collision or electron donation is promoted, so that the object can be processed efficiently.

In the treatment method of the present invention, the method for increasing the absolute value of the zeta potential by applying an electric field that fluctuates at a frequency of 20 Hz to 1 kHz to the dispersion solution is described in “1. Zeta potential control method of the present invention” above. The same technique can be used.
In the treatment method of the present invention, in order to further increase the absolute value of the zeta potential and further promote the chemical reaction, it is preferable to apply an electric field that varies at a frequency of 64 Hz to 800 Hz to the dispersion solution.

In the treatment method of the present invention, the treatment method can be a polishing method by using abrasive grains as particles dispersed in a solvent.
In this polishing method, the zeta potential of the abrasive dispersion can be lowered by applying a fluctuating electric field of 20 Hz to 1 kHz. This improves the dispersibility of the abrasive grains, increases the number of abrasive grains, increases the number of cutting edges, and further enhances the so-called chemical mechanical polishing action (chemical mechanical polishing action). Thus, the object can be polished efficiently. For example, in the case of using abrasive grains that are charged with negative charges on the surface, the negative charges on the surface of the abrasive grains are increased by applying a fluctuating electric field of 20 Hz to 1 kHz, and electrons are supplied to an object such as a silicon wafer. The strength of the interface is reduced, and the polishing action can be promoted.

5. Cleaning method of the present invention The cleaning method of the present invention is a cleaning method for removing impurity particles from an object by bringing the cleaning liquid into contact with the object, and an electric field that varies at a frequency of 20 Hz to 1 kHz is applied to the cleaning liquid. Thus, the absolute value of the zeta potential of the dispersion solution is increased, and the impurity particles are prevented from adhering to the object.
In the cleaning method of the present invention, the “cleaning liquid” may be any solvent that can disperse particles, and is not limited to, for example, ultrapure water or And water containing a surfactant.

The cleaning method of the present invention is characterized in that an electric field that fluctuates at a frequency of 20 Hz to 1 kHz is applied to the cleaning liquid. As a result, the zeta potential of the impurity particles attached to the object is increased, the impurity particles are easily dispersed in the cleaning liquid, and the removal from the object is promoted, and the once removed impurity particles adhere to the object again. Therefore, the cleaning efficiency can be increased.
Moreover, since the cleaning method of the present invention can improve the cleaning effect without increasing the temperature of the cleaning liquid, it can also be applied to objects that easily denature, including proteins.

In the cleaning method of the present invention, in order to increase the cleaning efficiency, it is preferable to apply the variable electric field while the cleaning liquid and the object are in contact with each other.
In order to further increase the cleaning efficiency, it is preferable to apply an electric field that varies at a frequency of 64 Hz to 800 Hz to the cleaning liquid.
In the cleaning method of the present invention, the same method as described in “1. Zeta potential control method of the present invention” may be used as a method of increasing the absolute value of the zeta potential by applying a varying electric field to the cleaning liquid. it can.

6). Zeta potential control device of the present invention A zeta potential control device of the present invention comprises a container for storing a dispersion solution in which particles are dispersed in a solvent, an electrode installed around the container, and an electrode having an arbitrary frequency of 20 Hz to 1 kHz. And a fluctuation voltage applying device that supplies the fluctuation voltage.
Here, the “container” may be any material as long as it can apply a varying electric field to the internal dispersion solution. It is preferable that an electrode can be installed inside.
The “electrode” can be placed on the top, bottom, left or right of the container as long as it can apply a varying electric field to the dispersion solution. However, since an electrochemical reaction occurs when contacted with the dispersion solution, it is preferable to provide an insulating layer so as not to contact with the dispersion solution or to prevent energization even when contacted with the dispersion solution. In order to efficiently apply a varying electric field to the dispersion solution, it is preferable to use a counter electrode capable of applying a voltage signal having a reverse sign.

The “fluctuating voltage applying device” used in the zeta potential control device of the present invention may be any device that can generate a fluctuating voltage, and is a combination of two or more devices. Also good. For example, it is preferable to use a device having a voltage amplifier and a function generator that supplies a signal to the voltage amplifier as the variable voltage generator.
The zeta potential control device of the present invention can supply a fluctuating voltage to the electrode, accumulate electric charges in the electrode to generate an electric field, and apply a fluctuating electric field of 20 Hz to 1 kHz to the dispersion solution in the container. There is an effect that the absolute value of the potential can be increased. In addition, since this zeta potential control device can supply an arbitrary fluctuating electric field of 20 Hz to 1 kHz or more to the dispersion solution, there is an effect that the degree of increasing the absolute value of the zeta potential of the dispersion solution can be adjusted.

7). Polishing apparatus of the present invention A polishing apparatus of the present invention includes a holding plate that holds a workpiece to be polished, a surface plate that contacts the workpiece held by the holding plate while applying a processing pressure while rotating, and a workpiece. A polishing apparatus having an abrasive slurry supply pipe for supplying abrasive slurry between an object and a surface plate, the apparatus comprising a variable electric field applying apparatus for applying a variable electric field of 64 Hz to 1 kHz to the abrasive slurry. And
Here, as the “holding plate” and the “surface plate”, the same one as that of a normal polishing apparatus can be used. The “holding plate” may be attached to a rotating polishing head.
In addition, the “fluctuating electric field applying device” can be one composed of an electrode and a fluctuating voltage applying device, which is installed in an abrasive slurry supply pipe, and an abrasive slurry having an increased zeta potential absolute value. Can be supplied. Further, the “fluctuating electric field applying device” may be installed at a position where a changing electric field can be applied to the abrasive slurry existing between the workpiece and the surface plate.

  Since the polishing apparatus of the present invention applies a fluctuating electric field of 20 Hz to 1 kHz to the abrasive slurry, the absolute value of the zeta potential of the abrasive slurry can be increased, and the dispersibility of the abrasive can be increased. There is an effect that the workpiece can be polished well.

One embodiment of the polishing apparatus of the present invention is shown in FIG.
As shown in FIG. 2, a polishing pad (10) is provided on the upper surface of a disk table-like surface plate (9), and the surface plate (9) is rotated by a rotating shaft (11). The workpiece (12) is fixed and held on a holding plate (14) provided on the polishing head (13), and the polishing head (13) can be rotated by a rotating shaft (11 '). . The abrasive slurry supply device (15) applies a varying electric field to the abrasive slurry supplied from the abrasive slurry supply pipe (16) to produce an abrasive slurry (17) with an increased absolute value of zeta potential. This is dropped on the polishing pad (10). Then, while supplying the abrasive slurry (17) between the polishing pad (10) and the workpiece (12), the processing pressure is applied to the workpiece (12) while rotating the surface plate (9) and the polishing head (13). The workpiece (12) can be polished by adding.

3 is a cross-sectional view of the abrasive slurry supply apparatus shown in FIG.
As shown in FIG. 3, the abrasive slurry supply device (15) has an abrasive slurry supply pipe (16) extending therethrough. An external electrode (18) is wound around the outside of the abrasive slurry supply pipe (16), and a line electrode (19) is installed inside the abrasive slurry supply pipe. The external electrode (18) and the line electrode (19) are connected to the positive and negative terminals of the high-voltage amplifier (7) via the lead wire (6), respectively. A function generator (8) is connected to the high-voltage amplifier (7), and the signal generated by the funk generator (8) is boosted by the high-voltage amplifier (7) and supplied to the two electrodes (18, 19). doing. Since the signal generated by the function generator (8) has a waveform that fluctuates periodically, the charges accumulated in the two electrodes fluctuate periodically. As a result, an electric field that fluctuates periodically is generated, and the fluctuating electric field is applied to the abrasive slurry that passes through the abrasive slurry supply pipe (16).

(Polishing experiment with controlled zeta potential of abrasive grains)
Using the polishing apparatus of the present invention shown in FIG. 2, the silicon wafer was polished while applying a variable electric field to the abrasive slurry.
As the abrasive slurry, an average particle size of 80 nm colloidal silica (SiO ₂ ) dispersed in a water-based solvent was used.
Then, using the abrasive slurry supply apparatus shown in FIG. 3, the abrasive slurry is subjected to a rectangular electric field having a voltage of 5 kV (1.7 kV / mm) and a frequency of 0, 8, 32, and 64 Hz. As described above, the conditions were changed for 8 seconds. The abrasive slurry to which a varying electric field was applied under each frequency condition was collected in a container, and the zeta potential was measured and the pH was measured using a zeta potential measuring device (Zeta Sizer Nano ZSP manufactured by Malvern). The result is shown in FIG.
As shown in FIG. 4, no change in the zeta potential was observed at a frequency of 8 Hz, but the absolute value of the zeta potential was improved at a frequency of 20 Hz or higher. Further, since the pH did not change under each condition, it was confirmed that the change in zeta potential was not due to the change in pH.

A polishing experiment of a silicon wafer (diameter: 50.8 mm) was performed using a polishing apparatus shown in FIG. 2 using the abrasive slurry supplied under each frequency condition. After polishing for 10 minutes, the weight before and after polishing was measured and converted to the polishing amount. The result is shown in FIG.
As is apparent from FIG. 5, the amount of polishing increased with the increase in the absolute value of the zeta potential. The polishing amount was improved by 11% at the maximum. Further, as is apparent from FIG. 6 showing a correlation graph between the zeta potential and the polishing amount, a clear correlation was observed between the zeta potential and the polishing amount.
This experimental result shows that with the decrease in the zeta potential of the abrasive slurry, the dispersibility of the abrasive grains is improved, and the number of cutting edges increases as the number of abrasive grains increases. At the same time, the negative charge of the abrasive grains increases. Is increased, electrons are supplied to the silicon wafer, the strength of the interface is lowered, and the polishing action is promoted.

  The zeta potential control method, dispersion solution production method, reaction method, processing method, cleaning method, zeta potential control device and polishing device of the present invention are useful in all industrial fields and clinical examination fields.

DESCRIPTION OF SYMBOLS 1 ... Container 2 ... Solvent 3 ... Particle 4 ... Electric double layer 5 ... Electrode 6 ... Lead wire 7 ... High voltage amplifier 8 ... Function generator 9 ... Constant Disc 10 ... Polishing pad 11, 11 '... Rotary shaft 12 ... Workpiece 13 ... Polishing head 14 ... Holding plate 15 ... Abrasive slurry supply device 16 ... Abrasive slurry Supply pipe 17 ... abrasive slurry 18 ... external electrode 19 ... wire electrode

Claims (17)

In a zeta potential control method for controlling the zeta potential of a dispersion solution in which particles are dispersed in a solvent,
A counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution,
A method of controlling a zeta potential, wherein an absolute value of a zeta potential of the dispersion solution is increased by applying an electric field that varies at a frequency of 20 Hz to 1 kHz to the dispersion solution by the counter electrode .   The method for controlling a zeta potential according to claim 1, wherein the particles are proteins, nucleic acids, or cells.   The zeta potential control method according to claim 1, wherein the particles are particles of an inorganic compound or a synthetic organic compound.   The zeta potential control method according to claim 1, wherein the frequency is a frequency of 64 Hz to 800 Hz.   The zeta potential control method according to claim 1, wherein the absolute value of the zeta potential is increased to 40 mV or more. Have a following A) -C) step, is characterized by using an electric field varying at the frequency of 20Hz～1kHz, zeta potential control method according to claim 1:
A) A counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution,
Applying an electric field varying by the counter electrode to the dispersion;
B) measuring the zeta potential of the dispersion solution to which a varying electric field is applied in the step of A);
C) When the absolute value of the zeta potential measured in the step B) is smaller than the absolute value of the target zeta potential, it is higher than the fluctuation electric field applied in the step A). Applying a frequency varying electric field to the dispersion. In a dispersion solution production method for producing a dispersion solution in which particles are dispersed in a solvent,
A counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution,
By applying an electric field that fluctuates at a frequency of 20 Hz to 1 kHz to the dispersion solution by the counter electrode, and increasing the absolute value of the zeta potential of the dispersion solution, the dispersibility of the particles in the dispersion solution is improved. A method for producing a dispersion solution.   The dispersion solution manufacturing method according to claim 7, wherein the frequency is a frequency of 64 Hz to 800 Hz. In a reaction method in which the particles and other compounds or particles are chemically reacted in a dispersion solution in which the particles are dispersed in a solvent,
A counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution,
The reaction method characterized by raising the absolute value of the zeta potential of the dispersion solution by applying an electric field varying at a frequency of 20 Hz to 1 kHz to the dispersion solution by the counter electrode .   The reaction method according to claim 9, wherein the frequency is a frequency of 64 Hz to 800 Hz. In the processing method of processing the target object by bringing the target object into contact with a dispersion solution in which particles are dispersed in a solvent,
A counter electrode is installed along the flow of the dispersion solution so that an electric field is applied perpendicularly to the flow direction of the dispersion solution,
A processing method characterized in that the object is processed by increasing an absolute value of a zeta potential of the dispersion solution by applying an electric field varying at a frequency of 20 Hz to 1 kHz to the dispersion solution by the counter electrode .   The processing method according to claim 11, wherein the frequency is a frequency of 64 Hz to 800 Hz.   The processing method according to claim 11, wherein the particles are abrasive grains, and the processing method is a polishing method. In the cleaning method for removing impurity particles from the object by contacting the object with the cleaning liquid,
A counter electrode is installed along the flow of the cleaning liquid so that an electric field is applied perpendicularly to the flow direction of the cleaning liquid,
By applying an electric field varying at a frequency of 20 Hz to 1 kHz to the cleaning liquid by the counter electrode, the absolute value of the zeta potential of the impurity particles dispersed in the cleaning liquid is increased, and the impurity particles adhere to the object. Cleaning method characterized by preventing.   The cleaning method according to claim 14, wherein the frequency is a frequency of 64 Hz to 800 Hz. A container for storing a dispersion solution in which particles are dispersed in a solvent, a tube for passing the dispersion solution, and an electric field perpendicular to the flow direction of the dispersion solution are installed along the flow of the dispersion solution. A zeta potential control device comprising : a counter electrode; and a variable voltage application device that supplies a variable voltage having an arbitrary frequency of 20 Hz to 1 kHz to the counter electrode. A holding plate that holds a workpiece to be polished, a surface plate that contacts the workpiece held by the holding plate while applying a processing pressure while rotating, and a gap between the workpiece and the surface plate In a polishing apparatus having an abrasive slurry supply pipe for supplying abrasive slurry,
A counter electrode is installed along the flow of the slurry so that an electric field is applied perpendicularly to the flow direction of the slurry,
A polishing apparatus comprising: a varying electric field applying device that applies a varying electric field of 64 Hz to 1 kHz to the counter electrode .