JP2003197575A - Apparatus and method for supplying abrasive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for supplying an abrasive which is capable of supplying an abrasive to a chemical mechanical polishing apparatus stably for a long period of time, by solving the problem that there is a lot of waste of the abrasive since the abrasive can no longer be used and has to be disposed due to a change in concentration of a solid content and a chemical after being left as it is for a long period of time. <P>SOLUTION: The abrasive supplying apparatus is provided with various non-contact type sensors for measuring concentration of a chemical and a solid content of a prepared abrasive in line, and a controller 27. The concentration of a chemical and a solid content of the abrasive are measured by the sensors, and the measurement results are inputted into the controller 27. The concentration of the chemical and the solid content of the abrasive are accurately controlled by performing feedback from the controller 27. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical mechanical polishing used for flattening an interlayer insulating film or an insulating film buried in a trench in a multilayer wiring process of a semiconductor substrate, or for forming a plug and a buried wiring. CMP ； Che
In particular, the present invention relates to a polishing agent supply apparatus and a polishing agent supply method used for performing chemical mechanical polishing in a mical mechanical polishing process.

[0002]

2. Description of the Related Art In recent years, the densification of semiconductor manufacturing processes,
Along with the miniaturization, various fine processing techniques have been researched and developed. Among them, chemical mechanical polishing is an essential technique for flattening an interlayer insulating film, forming a plug, separating an embedded element, and forming an embedded wiring.

In chemical mechanical polishing, an abrasive containing polishing particles called slurry (hereinafter simply referred to as slurry) is soaked in a polishing cloth, and the semiconductor substrate is polished on a rotating polishing platen to form a semiconductor substrate. This is a method of flattening the thin film on the surface. That is, in chemical mechanical polishing, polishing is performed with an abrasive interposed between the polishing cloth and the semiconductor substrate.

FIG. 4 is a schematic view showing a general structure of a conventional abrasive supply device (hereinafter referred to as a slurry supply device). A conventional slurry supply device includes a stock solution tank 101 in which an abrasive stock solution (hereinafter referred to as a slurry stock solution) 100 is stored, a chemical solution buffer tank 103 in which a chemical solution 102 such as an oxidizer is stored, and a stock slurry solution from the stock solution tank 101. 100 is supplied through a supply passage 104 connected to the stock solution tank 101, and a mixing tank 106 in which the chemical solution 102 is supplied from a chemical solution buffer tank 103 through a supply path 105 connected to the chemical solution buffer tank 103. ing.

A stock solution tank 10 is provided on the way to the supply passage 104.
Pump 107 for sucking the slurry stock solution 100 from 1
And a solenoid valve 108 for adjusting the flow of the slurry stock solution 100.
The supply passage 105 is provided with a metering pump 109 for sucking the chemical solution 102 from the chemical solution buffer tank 103 on the way.
And a solenoid valve 110 for adjusting the flow of the chemical liquid 102. Further, there is a supply path 112 that branches from the supply path 104 and returns the slurry stock solution 100 to the stock solution tank 101 via an electromagnetic valve 111.

In the mixing tank 106, a stirrer 113 is provided for stirring the supplied slurry stock solution 100 and the chemical solution 102, and a polishing agent mixed and adjusted with the slurry stock solution 100 and the chemical solution 102 (hereinafter referred to as slurry). 11)
And a liquid level sensor 115 for measuring the amount of liquid.

Further, in the slurry supply device, the supply tank 117 in which the slurry 114 is supplied from the mixing tank 106 through the supply passage 116 connected to the mixing tank 106.
The supply passage 116 is provided with a pump 118 for sucking the slurry 114 on the way and a solenoid valve 119 for adjusting the flow of the slurry 114. The slurry 114 held in the supply tank 117 is configured to be supplied onto the polishing platen 121 through the supply path 120 connected to the supply tank 117. The supply path 120 is provided with a roller pump 122 that sucks the slurry 114 from the supply tank 117 on the way, and a solenoid valve 123 that adjusts the flow of the slurry 114.

The conventional slurry supplying method of the slurry supplying apparatus will be described below. By closing the electromagnetic valve 111, opening the electromagnetic valve 108, and operating the pump 107, the slurry stock solution 100 is sucked up from the stock solution tank 101, and a fixed amount of the slurry stock solution 100 is transferred to the mixing tank 106 through the supply path 104. The stock amount of slurry is
It is measured by the liquid level sensor 115.

Next, the solenoid valve 110 is opened, and the metering pump 10 is opened.
9 is operated to transfer the chemical solution 102 from the chemical solution buffer tank 103 to the mixing tank 106 through the supply path 105 so that the chemical solution has a desired slurry concentration in the mixing tank 106. At this time, the flow rate of the chemical liquid 102 is controlled by defining the number of times the metering pump 109 is reciprocated. The slurry stock solution 100 and the chemical solution 102, which have entered the mixing tank 106, are sufficiently mixed by being constantly stirred by the stirrer 113.

The mixed slurry 114 is supplied to the solenoid valve 11
9 is opened, the pump 118 is operated, and it is sent to the supply tank 117 through the supply passage 116. Supply tank 117
The slurry 114 is supplied onto the polishing platen 121 from the above by opening the solenoid valve 123 and operating the roller pump 122.
It is performed through the supply path 120.

[0011]

As described above, in the conventional slurry supply device, the amount of the slurry 114 used varies due to fluctuations in the number of semiconductor substrates to be polished, troubles in the polishing device, and the like. Whether the supply of the slurry 114 from the supply tank 117 to the polishing platen 121 is stopped,
Alternatively, when the supply amount is extremely decreased, the slurry 114 prepared by the chemical solution remains in the supply tank 117 for a long time.

For example, in the case of a CMP slurry for metal which uses an aqueous solution of silica as a slurry stock solution and an aqueous solution of hydrogen peroxide (H ₂ O ₂ ) as a chemical solution, a supply tank 117 is used.
When the slurry 114 is left for a long time in the inside, the chemical concentration of the slurry 114 decreases. This is a long time
This is a phenomenon that occurs when hydrogen peroxide, which is a chemical solution, volatilizes from the slurry 114.

FIG. 5 is a characteristic diagram showing the relationship between the chemical concentration of the slurry and the polishing rate of the semiconductor substrate. As shown in FIG. 5, when the concentration of the chemical liquid in the slurry is lowered, the polishing rate is also lowered accordingly.

In order to improve this, it is possible to measure the chemical concentration with a titration analyzer at regular time intervals, control the chemical concentration of the slurry, and to drain the slurry that has changed below a certain concentration. it can. However, this method has a problem that the prepared slurry is wasted by the amount of the waste slurry.

It is also possible to measure the chemical concentration of the slurry with a titration analyzer, add a necessary amount of the chemical based on the measurement result, and re-formulate the concentration of the chemical within a specified value. The slurry used for titration and the slurry remaining in the pipe that is the supply path for transferring the slurry need to be drained, which causes a problem of waste of the slurry.

Further, by repeating the re-formulation of the slurry by this method, the solid content concentration of the particles in the slurry is lowered, and the polishing rate is lowered even if the chemical concentration of the slurry is a predetermined concentration. There was a problem that it would end up.

It is an object of the present invention to provide a polishing agent supply device and a polishing agent supply method for maintaining the solid content concentration and the chemical concentration of a slurry at predetermined values even when left for a long time.

[0018]

In order to solve the above-mentioned problems, the polishing agent supply apparatus of the present invention supplies a polishing agent stock solution supply means for supplying a polishing agent stock solution, and a chemical solution to be mixed with the polishing agent stock solution. Chemical liquid supply means, and at least one preparation tank for preparing the abrasive stock solution and the abrasive stock solution and the chemical solution supplied from the chemical solution supply means,
Measured by a chemical concentration measuring means for measuring the chemical concentration of the prepared polishing agent, a solid concentration measuring means for measuring the solid concentration of the polishing agent, the chemical concentration measuring means and the solid concentration measuring means. A controller for controlling the abrasive stock solution supply means and the chemical solution supply means until the chemical solution concentration and the solid content concentration reach set values, and controlling the supply amount of the abrasive stock solution and the chemical solution. Is characterized by.

The chemical concentration measuring means is a non-contact type ultrasonic chemical concentration meter, and the solid concentration measuring means includes a weight measuring device below the mixing tank and a non-contact liquid level sensor inside the mixing tank. Or an infrared transmissive sensor.

The polishing agent supply method of the present invention comprises a step of supplying the polishing agent stock solution to at least one mixing tank by the polishing agent stock solution supplying means, and a step of supplying the chemical solution to the mixing tank by the chemical solution supplying means. A step of preparing an abrasive by mixing the mixed abrasive stock solution and the chemical solution, a step of measuring the chemical solution concentration of the prepared abrasive by a chemical solution concentration measuring means, and a solid content concentration measuring means, The step of measuring the solid content concentration of the abrasive, the controller compares the measured chemical concentration and the solid concentration with a set value, and the abrasive stock solution supply means and the chemical solution supply until the set value is reached. Controlling the means and controlling the supply amounts of the stock solution of the polishing agent and the chemical solution.

Further, according to the abrasive supply method of the present invention, when the chemical concentration of the prepared abrasive changes with time due to a change with time lower than a set value, the chemical is added to re-formulate the solid of the abrasive. When the partial concentration is lower than the set value, an abrasive stock solution is added and re-formulation is performed.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic view of a slurry supply device according to a first embodiment of the present invention. Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, the slurry supply apparatus of this embodiment stores a slurry stock solution 1 containing abrasive particles and has a sealed stock solution tank 2 and a chemical solution such as an oxidizing agent, which is hydrogen peroxide in this description. Chemical solution buffer tank 4 for storing water (H ₂ O ₂ ) 3 and preparation supply tank (preparation tank) 5 for mixing and preparing the slurry stock solution 1 and hydrogen peroxide solution 3
a, 5b, and pipes 6a, 6b for supplying the slurry stock solution 1 from the slurry stock solution tank 2 to the two preparation supply tanks 5a, 5b, respectively, and the hydrogen peroxide solution 3 from the chemical buffer tank 4 to the preparation supply tanks 5a, 5b. In order to finely adjust the concentration of the chemical liquid of the hydrogen peroxide solution 3 in the supply tanks 5a and 5b, the supply tubes 7a and 7b,
Pipes 8a and 8b provided to bypass each 7b
And a N ₂ pipe 9 for pressure-feeding the hydrogen peroxide solution 3 from the chemical buffer tank 4 with nitrogen (N ₂ ).

In the slurry stock solution tank 2, the slurry stock solution 1 is sucked from the slurry stock solution tank 2 and a pipe 6 is drawn.
A suction nozzle 10 for sending out to the a and 6b and a jet nozzle 11 for returning the slurry stock solution 1 to the slurry stock solution tank 2 while jetting it are arranged.

On the other hand, in the mixing supply tanks 5a and 5b,
Jet nozzles 12a and 12b for jetting and supplying the slurry stock solution 1 to the compounding supply tanks 5a and 5b through the pipes 6a and 6b, respectively, are arranged, and the chemical solution buffer tank 4 through the pipes 7a and 7b. Supply nozzles 13a and 13b are provided to supply the compound supply tanks 5a and 5b while jetting. In addition, a slurry 14 prepared by mixing the slurry stock solution 1 and hydrogen peroxide solution 3
In order to finely adjust the concentration of the hydrogen peroxide solution 3 of each of a and 14b, the preparation supply tanks 5a and 5b are supplied from the pipes 8a and 8b.
Supply nozzles 15a, 15 for supplying while ejecting to
b is arranged.

From the compounding supply tanks 5a and 5b to the polishing platen 16 of the chemical mechanical polishing apparatus, the compounded slurry 14
A pipe 17 is arranged to supply a and 14b, and a nozzle 18 is installed on the polishing platen 16 to discharge the slurries 14a and 14b.

The mixed slurries 14a and 14b are returned to the mixing supply tanks 5a and 5b, and the pipes 17a and 19b are respectively bypassed to the pipes 17 for stirring.
Is arranged and nozzles 20a for ejecting the prepared slurries 14a, 14b into the preparation supply tanks 5a, 5b,
20b are arranged respectively.

Flow rate adjusting valves 22a to 22h, which are control valves for adjusting the flow rate, are connected to the respective pipes. Further, a liquid feed pump 23 is connected to the pipes 6a and 6b, and the liquid feed pump 23 supplies the slurry stock solution 1 to the compounding supply tanks 5a and 5b through the flow rate control valves 22b and 22e. Slurry stock solution tank 2 through the flow rate control valve 22a
It is ejected from the ejection nozzle 11 to the bottom surface side and returned.

Further, the liquid feed pumps 25a, 2b are also connected to the pipes 19a, 19b via the flow rate control valves 22j, 22l, respectively.
5b is arranged to stir the prepared slurry 14a, 14b in the preparation supply tanks 5a, 5b by means of the liquid feed pump 25.
the slurry 14a, 14b with the nozzle 2
It is performed by jetting from 0a and 20b.

A liquid feed pump 26 is connected to the pipe 17 connected to the blending supply tanks 5a and 5b via flow rate adjusting valves 22i and 22k, and is blended to the polishing platen 16 via a nozzle 18. The slurries 14a and 14b are supplied. The flow rate control valves 22c and 22f are respectively connected to the pipe 7a and
7b, the flow rate adjusting valve 22h is placed in the pipe before branching the pipes 7a and 7b, and the flow rate adjusting valves 22d and 22g are placed in the pipes 8a and 8b, respectively.

In order to measure the concentration of the hydrogen peroxide solution 3 in the prepared slurries 14a, 14b in the preparation supply tanks 5a, 5b, a non-contact ultrasonic type is used as a chemical solution concentration measuring means in the pipes 19a, 19b. Chemical concentration meter 27a, 27b
To place. The measurement results of the chemical concentration meters 27a and 27b are input to the controller 27. Controller 27
Are the flow rate control valves 22a to 22h and the liquid feed pumps 23, 2
5a, 25b and 26 are controlled, and a chemical concentration meter 27a,
Based on the calculation result of 27b, the concentration of the hydrogen peroxide solution 3 in the slurries 14a and 14b is finely adjusted.

In order to measure the weight of the slurries 14a and 14b supplied into the mixing and supplying tanks 5a and 5b, load cells (weight measuring devices) 28a and 28b are arranged below the mixing and supplying tanks 5a and 5b, respectively. Further, non-contact type liquid surface sensors 29a and 29b are arranged to measure the liquid surface heights in the mixing supply tanks 5a and 5b and calculate the volumes of the supplied slurries 14a and 14b.

In this embodiment, the slurry undiluted solution tank 2 is used as the undiluted abrasive liquid supply means for supplying the undiluted abrasive liquid.
And pipes 6a and 6b, a liquid feed pump 23, and flow rate control valves 22b and 22e. Further, as the chemical liquid supply means for supplying the chemical liquid, the chemical liquid buffer tank 4, the pipes 7a, 7b, 8a, 8b, and the flow rate control valves 22c, 22.
It is provided with d, 22f, 22g, 22h and N ₂ pipe 9.

Next, the necessity of adjusting the chemical concentration will be described.

Here, in the case of a slurry using a polishing agent using fumed silica as a slurry stock solution 1 used for chemical mechanical polishing of a tungsten film (hereinafter referred to as W film) and hydrogen peroxide solution as an oxidizing agent. Taking as an example, for the sake of simplification of description, the necessity of adjusting the solid content concentration of the slurry and the hydrogen peroxide solution concentration will be described for one of the blending supply tanks 5a.

Usually, hydrogen peroxide 3 is volatilized from the slurry 14a in the compounding supply tank 5a when the chemical mechanical polishing apparatus is used less frequently due to waiting time without polishing semiconductor substrate or equipment trouble. As a result, the concentration of hydrogen peroxide solution in the slurry 14a in the blending supply tank 5a decreases. FIG. 2 is a characteristic diagram showing the relationship between the elapsed time and the concentration of hydrogen peroxide solution in the slurry after the slurry 14a was prepared in the preparation supply tank 5a and then left without using the slurry 14a. . Figure 2
According to the data, if the slurry 14a once prepared is left unused without being used, the hydrogen peroxide concentration will decrease with the passage of time.

Further, as shown in FIG. 5, the polishing rate becomes slower as the concentration of the chemical liquid in the slurry decreases.

Therefore, in order to stabilize the polishing rate, the prepared slurry is used within a fixed time, or the slurry after a fixed time is readjusted so as to increase the concentration of hydrogen peroxide solution by re-formulation. There is a need to do.

Next, a method of adjusting the solid content concentration of the slurry and the hydrogen peroxide concentration will be described. W as in the previous description
Taking as an example the case of a slurry using fumed silica used for chemical mechanical polishing of a film and hydrogen peroxide water as an oxidizing agent, the solid content concentration and the hydrogen peroxide water concentration are targeted for the preparation and supply tank 5a. The adjustment method of is described.

It is assumed that the wafer is chemically mechanically polished by using the slurry 14a in the compounding supply tank 5a. The amount of residual slurry in the compounding supply tank 5a is
It is constantly monitored by 8a. The load cell 28a switches the supply of the slurry to the polishing platen 16 to the blending supply tank 5b when the amount of residual slurry in the blending supply tank 5a falls below a certain amount.

A more detailed description will be given. First, the current volume and weight of the slurry are measured by the liquid level sensor 29a and the load cell 28a, and the controller 27 is made to read the numerical value. Next, the slurry 14 in the compounding supply tank 5a
A command from the controller 27 is given to the transfer pump 23 and the flow rate control valves 22b, 22h, and 22c so that the concentration of the chemical solution and the concentration of the solid content of a become predetermined values.
The slurry stock solution 1 and hydrogen peroxide solution 3 are introduced therein. At this time, in order to agitate the slurry 14a in the blending supply tank 5a, the flow rate adjusting valve 22j and the liquid feed pump 25a are operated to eject the slurry 14a from the nozzle 20a, thereby introducing the slurry introduced into the blending supply tank 5a. Stock solution 1 and hydrogen peroxide solution 3 are mixed.

Next, the liquid level of the slurry 14a, the weight and the chemical liquid are measured by the load cell 28a, the liquid level sensor 29a, and the chemical concentration meter 27a as the solid concentration measuring means for measuring the solid concentration of the polishing agent. Measure the concentration.
Based on the pre-measured data stored in the database,
The volume of the slurry 14a is obtained from the liquid level height. Further, depending on the volume and weight of the slurry 14a, the slurry 14
The solid content concentration of a is determined. The deviation from the target value can be detected by inputting this measurement result to the controller 27 and comparing it with a predetermined target value. For example, when the concentration of the chemical liquid is low, the concentration of the chemical liquid in the slurry 14a can be finely adjusted by opening the flow rate control valves 22h and 22d for a certain period of time. When the solid content concentration of the slurry 14a is low, the flow rate adjusting valve 22b is opened and the liquid feeding pump 23 is operated to perform fine adjustment.

FIG. 3 is a schematic view of a slurry supply device according to the second embodiment of the present invention. Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The slurry supply device of this embodiment is characterized by using an infrared transmissive sensor for measuring the solid content concentration in the slurry.

As shown in FIG. 3, the infrared transmission sensor 3
0a and 30b are installed in series in a part of the pipe 17 connected to the preparation and supply tanks 5a and 5b. By measuring the amount of infrared rays transmitted through the pipe 17, the solid concentration of the slurries 14a and 14b can be measured in a non-contact manner as in the first embodiment.

Next, a method of re-adjusting the hydrogen peroxide concentration will be described.

A case where the chemical concentration of the slurry in the compounding supply tank 5a is lowered as shown in FIG. 2 due to a trouble of the chemical mechanical polishing apparatus or waiting for a product will be described.

The chemical concentration of the slurry in the preparation and supply tank 5a is measured by the non-contact chemical concentration meter 27a at regular intervals, and the measurement result is input to the controller 27. If the chemical concentration falls below the specified standard, the controller 2
In response to a command from 7, the flow rate control valves 22d and 22h are opened for a certain period of time, and the hydrogen peroxide solution 3, which is a chemical solution, is additionally supplied to the preparation supply tank 5a. Further, the flow rate adjusting valve 22j is opened and the liquid feeding pump 25a is operated to stir the inside of the preparation supply tank 5a. When the stirring is completed, the chemical concentration is again confirmed by the chemical concentration meter 27a. By the above method, even if the product waiting time is long or the unused time of the slurry becomes long due to equipment trouble etc., the concentration of the chemical liquid in the slurry can be controlled within a certain standard, and a stable polishing rate can be obtained. Things are possible.

Next, an explanation will be given of an adjusting method in the case where the solid content concentration in the slurry is lowered in the case where the re-formulation of the chemical solution is repeated a plurality of times.

The solid content concentration in the slurry is determined by measuring the weight of the compounding supply tank 5a and the liquid level of the tank.
It can be calculated from the result of measuring the weight and volume of the slurry 14a.

When the solid content concentration of the slurry 14a falls below a predetermined standard range, the transfer pump 23 is operated for a certain period of time according to a command from the controller 27, and the flow rate control valve 2 is operated.
The slurry stock solution 1 is additionally supplied by opening 2b. Further, the flow rate control valve 22j is opened, and the liquid feed pump 25
By operating a, the inside of the preparation supply tank 5a is agitated. When the stirring is completed, the solid content concentration and the chemical solution concentration are checked again. By repeating the re-formulation of the chemical solution by the above method, even if the solid content concentration in the slurry is lowered, the solid content concentration in the slurry, the chemical solution concentration can be controlled within a certain standard, and a stable polishing rate can be obtained. Is possible.

Next, a method of coping with the agglomeration of the slurry when the storage time of the above-mentioned re-prepared slurry becomes extremely long will be described.

It is generally known that an abrasive containing silica or the like as abrasive grains aggregates when it is subjected to shear stress such as stirring for a long period of time. If the method of slurry re-formulation described above is used, a slurry having a long unused period will be supplied semipermanently except for the limitation of the tank capacity.
For example, it is known that when chemical mechanical polishing is performed in a state in which a slurry containing silica as abrasive grains causes particle aggregation, micro scratches increase. Therefore, the storage time is limited by using the timer in the controller 27 so that the prepared slurry is not stored in an unused state.

The relationship between the elapsed time and the increase in particle size is investigated in advance by experiments, and the storage time is determined. First, the timer in the controller 27 is used to record the preparation completion time of the preparation supply tank 5a in the normal state. When re-blending is repeated and the unused time of the slurry has passed and the storage time has reached the determined storage time or longer, the flow rate control valves 22i and 22m are opened by a command from the controller 27, and the slurry in the blending supply tank 5a is drained. To do. When the waste liquid is finished, the slurry is re-supplied and the blending is started again according to the procedure of the first embodiment.

According to the above method, since chemical mechanical polishing is not performed in the state where the slurry is aggregated, the quality of the product is not deteriorated.

Although the above embodiment has been described with respect to one of the mixing and supplying tanks 5a, the same applies to the mixing and supplying tank 5b. Further, the slurry stock solution and the chemical solution are not limited to those described above, and other compounds may be used as the mixing method.

[0057]

As described above, according to the method of preparing and supplying the abrasive of the present invention, when the prepared slurry is stored for a long time, the concentration of the chemical liquid is lowered due to the effect of volatilization from the slurry. However, fluctuations in the polishing rate can be avoided. Since the method of re-blending is provided for the decrease in the concentration of the chemical solution and the solid content, the amount of the discarded slurry can be greatly reduced, and the slurry can be used efficiently. Since the non-contact type is used for measuring the concentration of the chemical liquid and the solid content, the slurry is not aggregated or contaminated.

[Brief description of drawings]

FIG. 1 is a schematic view of a polishing agent supply device according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the hydrogen peroxide concentration in the polishing agent and the elapsed time.

FIG. 3 is a schematic diagram of a polishing agent supply device according to a second embodiment of the present invention.

FIG. 4 is a schematic view of a conventional polishing agent supply device.

FIG. 5 is a characteristic diagram showing the relationship between chemical concentration and polishing rate.

[Explanation of symbols]

2 Slurry stock solution tank 4 Chemical solution buffer tank 5a, 5b Compound supply tank 6a, 6b piping 7a, 7b piping 8a, 8b piping 16 Polishing surface plate 17 Piping 19a, 19b piping 22a-22m Flow control valve 23 Liquid Delivery Pump 25a, 25b Liquid transfer pump 26 Liquid Delivery Pump 27a, 27b Chemical concentration meter 28a, 28b load cell 29a, 29b Liquid level sensor 30a, 30b Infrared transmission sensor

Claims (10)

[Claims] 1. An abrasive stock solution supply means for supplying an abrasive stock solution, a chemical solution supply means for supplying a chemical solution to be mixed with the abrasive stock solution, an abrasive stock solution supply means, and a chemical solution supply means. At least one preparation tank for preparing the polishing agent stock solution and the chemical solution, a chemical solution concentration measuring unit for measuring the chemical concentration of the prepared polishing agent, and a solid content concentration measuring unit for measuring the solid content concentration of the polishing agent. Controlling the abrasive stock solution supply means and the chemical solution supply means until the chemical solution concentration and the solid content concentration measured by the chemical solution concentration measurement means and the solid content concentration measurement means reach a set value, A polishing agent supply apparatus comprising: a stock solution and a control device for controlling the supply amount of the chemical solution. 2. The polishing agent supply apparatus according to claim 1, wherein the chemical concentration measuring means is a non-contact ultrasonic type chemical concentration meter. 3. The solid content concentration measuring means comprises a weight measuring device arranged below the mixing tank, and a non-contact liquid level sensor arranged in the mixing tank.
The abrasive supply device according to. 4. The polishing agent supply apparatus according to claim 1, wherein the solid content concentration measuring means is an infrared transmission type sensor. 5. An abrasive stock solution mixed with the undiluted solution supply means for supplying the undiluted solution to at least one mixing tank, a chemical solution supply means for supplying the undiluted solution to the preparation tank. And a step of preparing an abrasive by mixing the chemicals, a step of measuring the chemical concentration of the prepared abrasive by a chemical concentration measuring means, and a solid concentration of the abrasive by a solid concentration measuring means. And the control device compares the measured chemical concentration and the solid content concentration with a set value, and controls the abrasive stock solution supply means and the chemical supply means until the set value is reached, and the polishing is performed. And a step of controlling the supply amount of the stock solution and the chemical solution. 6. The polishing agent supply method according to claim 5, wherein when the concentration of the chemical liquid in the prepared polishing agent changes to a value lower than a set value due to a change with time, the chemical liquid is added and re-formulation is performed. . 7. The polishing agent supply method according to claim 5, wherein when the concentration of the solid content of the polishing agent is lower than a set value, the polishing agent stock solution is added and re-formulation is performed. 8. A step of setting a time for the polishing agent to increase in particle size due to agglomeration of polishing particles, draining the polishing agent after the set time, and re-compounding from the beginning The polishing agent supply method according to claim 5. 9. The polishing agent supply method according to claim 6, wherein the re-blending is automatically performed according to a command from the control device. 10. A mixing tank provided with a plurality of mixing tanks, which supplies the polishing agent when the chemical concentration and solid content concentration of the polishing agent are lower than set values or when the remaining amount of the polishing agent is low. The polishing agent supply method according to claim 5, wherein one preparation tank is switched to another preparation tank to re-prepare the one preparation tank.