JP2010247310A - Method and device for supplying slurry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for supplying slurry reducing the amount of slurry remaining in a drum after use to the minimum. <P>SOLUTION: The method and device for supplying the slurry includes (1) a normal process in which the slurry in a slurry supplying tank in use is supplied to a use point and circulated through a circulation line by a slurry circulation pump, and (2) a transfer process in which a switching valve is switched at the stage where the amount of liquid in the slurry supplying tank in use becomes the starting level of transfer, the slurry in the slurry supplying tank in use is supplied to the use point and circulated through the circulation line by the slurry circulation pump, and almost total amount of the slurry remaining in the slurry supplying tank in use is transferred to a standby slurry supplying tank. By repeating these processes, the slurry remaining in the slurry supplying tank in use is transferred to the standby slurry supplying tank. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a slurry supply method and apparatus for supplying slurry used in a CMP (Chemical Mechanical Polishing) process in a semiconductor manufacturing process to a use point using two or more slurry supply tanks. is there.
The slurry supply method and apparatus according to the present invention are not limited to supply of slurry, but include supply of chemicals and the like used in the CMP process.

  The conventional switching mechanism of a device capable of setting a plurality of slurry supply tanks is a simple operation of switching to the next set slurry supply tank in sequence when one slurry supply tank becomes empty. The empty detection level is set to a height that takes into account the margin for preventing switching failure at the suction tube tip position. In addition, in the case of a fluid that needs to be stirred, the slurry supply tank is detected empty based on the height at which the stirring blade of the stirrer is not exposed on the liquid surface. This type of stirrer tends to increase the stirring efficiency of the slurry, and its structure tends to be complicated and large, and it cannot be used up to the height of the stirring blade, and there are many residual slurries that must be discarded ( Patent Document 1).

Japanese Patent Laid-Open No. 11-028664

  However, in the above-described conventional apparatus, the suction tube tip is not always located at the same height every time due to manufacturing dimensional error of the suction tube and slurry supply tank, displacement at the time of installation, etc., and the empty of the slurry supply tank is detected. Since there is a risk of air biting before starting, the empty setting position of the slurry supply tank has to be set to a height that takes into account a sufficient margin, so the remaining amount of slurry or chemical solution could not be reduced. .

Further, in the above-described conventional apparatus, in a system equipped with a stirrer, the slurry supply tank empty setting position must be set to a height at which the stirring blade is not exposed in order to prevent liquid scattering and adhesion drying. The residual amount of could not be reduced.
Moreover, in the above-described conventional apparatus, in order to fully use the remaining slurry or chemical liquid when the slurry supply tank reaches the empty level, the slurry supply tank is removed once and manually connected to a new slurry supply tank. There was a need to add and there was no automatic way to achieve it.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and immediately remain in the slurry supply tank in use without stopping the supply to the point of use before the slurry supply tank in use becomes empty. An object of the present invention is to provide a slurry supply method and apparatus equipped with a function of transferring the slurry in a standby state to a slurry supply tank that is on standby and reducing the remaining amount of the slurry supply tank in use.

In order to achieve the above object, the present invention measures, as a first problem solving means, one in-use slurry supply tank, one or more standby slurry supply tanks, and the amount of liquid in each slurry supply tank. And a slurry circulation line from each slurry supply tank to the use point, a slurry circulation pump, a switching valve for each slurry supply tank, and a circulation line from the slurry supply tank in use to the use point. After that, it is returned to the standby slurry supply tank by the switching valve of each slurry supply tank in the return line, and consists of a slurry control unit for continuously supplying the slurry to the use point,
1) A normal process of supplying and circulating the slurry in the slurry supply tank in use to a use point through a circulation line by a slurry circulation pump;
2) When the amount of liquid in the slurry supply tank in use reaches the transfer start level, the switching valve is switched, and the slurry in the slurry supply tank in use is transferred to the use point via the circulation line by the slurry circulation pump. The slurry supply tank in use is emptied by repeating the supply and circulation and the transfer step of transferring substantially the entire amount of slurry remaining in the slurry supply tank in use to the slurry supply tank in standby. Before stopping the supply to the point of use, the slurry remaining in the slurry supply tank in use can be quickly transferred to the slurry supply tank in standby to reduce the remaining amount of the slurry supply tank in use. It is an object of the present invention to provide a slurry supply method characterized by having a function to perform.

  As a second problem solving means, the present invention provides one in-use slurry supply tank, one or more standby slurry supply tanks, a sensor for measuring the amount of liquid in each slurry supply tank, and each slurry supply The slurry circulation line from the tank to the point of use, the slurry circulation pump, the switching valve of each slurry supply tank, and the slurry in the return line after passing through the circulation line from the slurry supply tank in use to the point of use A slurry supply unit comprising a slurry control unit for returning to a slurry supply tank in standby by a supply valve of the supply tank and continuously supplying the slurry to a use point, and performing the slurry supply method. To provide an apparatus.

The present invention provides, as a third problem solving means, one in-use slurry supply tank, one or more standby slurry supply tanks, a sensor for measuring the amount of liquid in each slurry supply tank, and each slurry supply The slurry circulation line from the tank to the point of use, the slurry circulation pump, the switching valve of each slurry supply tank, and the slurry in the return line after passing through the circulation line from the slurry supply tank in use to the point of use It consists of a slurry control unit for returning to the slurry supply tank in standby by the supply tank switching valve and continuing to supply the slurry to the use point,
1) A normal process of supplying and circulating the slurry in the slurry supply tank in use to a use point through a circulation line by a slurry circulation pump;
2) When the amount of liquid in the slurry supply tank in use reaches the transfer preparation start level, the slurry in the slurry supply tank on standby by the slurry circulation pump is changed to the slurry supply tank in use by switching the circulation line. A transfer preparation step that reversely transfers, prevents the capacity of the slurry supply tank in a standby state from being exceeded, and increases the degree of freedom of the transfer amount;
3) When the amount of liquid in the slurry supply tank on standby reaches the level ready for transfer, the slurry in the slurry supply tank in use is supplied again to the use dropper by switching the circulation line by the slurry circulation pump. Normal process to do,
4) When the amount of liquid in the slurry supply tank in use reaches the transfer start level, the switching valve is switched, and the slurry in the slurry supply tank in use is transferred to the use point via the circulation line by the slurry circulation pump. The slurry supply tank in use is emptied by repeating the supply and circulation and the transfer step of transferring substantially the entire amount of slurry remaining in the slurry supply tank in use to the slurry supply tank in standby. Before stopping the supply to the point of use, the slurry remaining in the slurry supply tank in use can be quickly transferred to the slurry supply tank in standby to reduce the remaining amount of the slurry supply tank in use. It is an object of the present invention to provide a slurry supply method characterized by having a function to perform.

  The present invention provides, as a fourth problem solving means, one in-use slurry supply tank, one or more standby slurry supply tanks, a sensor for measuring the amount of liquid in each slurry supply tank, and each slurry supply The slurry circulation line from the tank to the point of use, the slurry circulation pump, the switching valve of each slurry supply tank, and the slurry in the return line after passing through the circulation line from the slurry supply tank in use to the point of use A slurry supply unit comprising a slurry control unit for returning to a slurry supply tank in standby by a supply valve of the supply tank and continuously supplying the slurry to a use point, and performing the slurry supply method. To provide an apparatus.

  As a fifth problem-solving means, the present invention provides that the slurry supply tank is equipped with a stirrer, the transfer start level is set to the position of the stirrer blade of the stirrer, and the liquid level of the slurry supply tank in use is that of the stirrer blade. Stop the stirrer before it falls below the height to prevent splashing of liquid and subsequent sticking and drying, and quickly remove the slurry remaining in the slurry supply tank in use without stopping the supply to the point of use. An object of the present invention is to provide the slurry supply method, which is equipped with a function of transferring the residual liquid to a slurry supply tank in standby and reducing the remaining amount of slurry in the slurry supply tank in use.

  As a sixth problem solving means, the present invention uses a weight strain sensor as the sensor, continuously monitors the liquid amount of the slurry, and inputs the liquid amount signal to the control unit, thereby starting the transfer control. Another object of the present invention is to provide a slurry supply method characterized by having a function of freely setting or changing the liquid amount to be finished.

  The seventh aspect of the present invention provides the seventh problem solving means, wherein the slurry control unit has a timer function in which the transfer operation ends after a set time after the liquid amount in the slurry supply tank falls below the transfer end set value, and the transfer ends. By setting the set value to the amount of liquid that the tip of the suction tube is sufficiently immersed and optimizing the timer, manufacturing error of the suction tube and slurry supply tank, installation error of suction tube, reading error of liquid amount measurement sensor, etc. It is an object of the present invention to provide a slurry supply method characterized by further reducing the amount of residual slurry by making it unnecessary to secure a margin in anticipation of switching failure of the slurry supply tank.

  According to an eighth aspect of the present invention, there is provided a slurry supply method, wherein the slurry control unit has a safety mechanism for preventing a capacity overflow of the slurry liquid amount by setting an upper limit of the slurry liquid amount. It is to provide.

  According to the present invention, as the ninth problem solving means, when only one slurry supply tank is set, the slurry control unit automatically recognizes it and performs the transfer preparation step and the transfer step. First, as soon as it is confirmed that a new slurry supply tank is set and ready for use, the slurry preparation method is controlled to start the transfer preparation step and the transfer step. It is to provide.

  The tenth problem solving means of the present invention is that, as a tenth problem solving means, when the slurry supply tank involved in the operation is removed during the transfer preparation step or the transfer step, the slurry control is immediately performed. An object of the present invention is to provide a slurry supply method which has a function of canceling the transfer step and notifying that the removed slurry supply tank is empty.

According to the method of the present invention, by setting the control function of the slurry control unit,
1) Before the slurry supply tank in use becomes empty, the amount of liquid remaining in the slurry supply tank is minimized by transferring the slurry or chemical remaining in the slurry supply tank to a new slurry supply tank. be able to.
2) By using the normal circulation line from the in-use slurry supply tank to the point of use and the slurry supply tank switching valve in the return line as the residual liquid transfer path, without interrupting the supply to the point of use, Can be transported.
3) Since the slurry supply tank filled with the slurry or the chemical solution has insufficient space for receiving the transferred slurry or chemical solution, the transfer destination is provided by providing a transfer preparation step before performing the transfer operation. If the slurry is reversely transferred from the slurry supply tank to the transfer source slurry supply tank and the free capacity of the transfer destination slurry supply tank is increased, the degree of freedom of the transfer amount and transfer level set value can be increased by increasing the allowable transfer amount. Can be increased.
4) In a system equipped with a stirrer, the amount of liquid remaining in the slurry supply tank can be minimized by starting transfer before the stirring blade comes out on the liquid surface.
5) If a weight strain sensor is used as a sensor for measuring the amount of liquid in the slurry supply tank, the amount of liquid can be continuously monitored, and transfer control is started by inputting the amount signal to the controller. Alternatively, the liquid amount to be finished can be easily set or changed.
6) When the empty level of the slurry supply tank is set to the same height as the tip of the suction tube, the liquid will be affected by the manufacturing error of the suction tube and slurry supply tank, the error of attaching the suction tube, and the reading error of the liquid amount measurement sensor. There is a risk that air supply occurs before the quantity measuring sensor detects that the slurry supply tank is empty, and the slurry supply tank switching is not normally performed. Therefore, it is necessary to set the slurry supply tank empty level to a high position as a margin, which leads to an increase in the remaining amount. In the present invention, it is possible to reduce the remaining amount by setting the transfer end level with a margin and continuing the transfer operation for a timer set time from there.
7) By setting the upper limit of the liquid volume, the liquid volume can be prevented from overflowing.
8) When only one slurry supply tank is set, it is automatically recognized and waits without carrying out transfer preparation control and transfer control, and a new slurry supply tank is set and becomes ready for use. As soon as it has been confirmed, the transfer preparation process and the transfer process can be started.
9) If the slurry supply tank involved in the operation was removed during the transfer preparation process or the transfer process, the transfer preparation process or the transfer process was immediately stopped, and the removed slurry supply tank became empty Can be notified.

Schematic diagram showing the hardware configuration of the present invention and the normal process before the transfer control is activated Schematic diagram showing the transfer process Schematic diagram showing normal process after transfer process and drum switching Schematic diagram showing normal process before transfer control is activated Schematic diagram showing the transfer preparation process Schematic diagram showing the normal process Schematic diagram showing the transfer process Schematic diagram showing normal process after transfer process and drum switching

1 to 3 are diagrams showing an embodiment of the present invention that does not use a transfer preparation process. FIG. 1 shows a hardware configuration of the present invention, and at the same time, a normal process before the transfer control is activated. FIG. 2 is a schematic diagram showing a transfer process, and FIG. 3 is a schematic diagram showing a transfer process and a normal process after drum switching.
The present invention can be applied using the same principle when the number of drums is three or more. Further, the gist of the present invention described below describes the control when the number of drums is two and when switching from the drum 1 to 2, but the case when switching from the drum 2 to 1 is based on the same principle. .

  FIG. 1 shows the hardware configuration of the present invention and the operating state before the transfer control is activated. The following steps are all performed by adjusting the control function of the slurry controller 17. The process display 22 of the drum 1 is “in use”, and the process display 23 of the drum 2 is “usable”, that is, the drum 1 is ready for use after it is empty. The combination of drums 1 and 2 and “in use” and “usable” is determined by the drum that is being used at that moment, and is reversed in accordance with drum switching. By operating the circulation pump 4 with the valves 3-1 and 3-3 open and the valves 3-2 and 3-4 closed, the slurry or chemical liquid in the drum 1 is sucked by the insert tube 12. Then, it returns to the drum 1 by the insert tube 13 via the circulation line 6 at the use point 5. In the use point 5, the slurry or chemical in the system is consumed by opening the valve 3-5 at an arbitrary timing. At this time, the agitators 7 and 7 of the drums 1 and 2 continue the agitation operation and have a role of maintaining a uniform state of the slurry or the chemical solution.

  FIG. 2 represents the transfer process. The process indications 22 and 23 of the drum 1 and the drum 2 are in use / transferring and available / transferring, respectively. As a result of the continuous consumption of the slurry at the use point 5, when the liquid amount 8 of the drum 1 is kept below the stirrer stop level (transfer start level) 10 and above the drum empty level 11, the stirrer 7 Stops and the transfer process starts. During the transfer process, the circulation pump 4 is operated with the valves 3-1 and 3-4 open and the valves 3-2 and 3-3 closed, so that the slurry or chemical in the drum 1 is inserted into the insert tube. It is sucked by the tube 12 and transferred to the drum 2 by the insert tube 14 via the circulation line 6 at the use point 5. During the transfer process, the supply of the slurry or the chemical liquid to the use point 5 is continued, and can be arbitrarily used by opening and closing the valve 3-5. The transfer process continues to decrease because the liquid amount 8 of the drum 1 is sent to the drum 2, drops below the drum empty level 11, and then continues for the time of the drum empty transfer continuation timer (not shown). The drum 1 is empty. At this time, the remaining amount of slurry in the drum 1 is reduced to the limit of the amount of liquid that the insert tube 12 can physically suck. On the other hand, since the liquid amount 9 of the drum 2 continues to increase, even when the liquid amount 8 of the drum 1 does not fall below the drum empty level 11, when the liquid amount 9 of the drum 2 reaches the transfer receiving stop level 16, An interlock for preventing overflow is provided so that the transfer process is completed. Further, since the stirrer is stopped during the transfer process and the ability to maintain the uniform state of the slurry or the chemical solution is reduced, an interlock is provided when the transfer process exceeds the stirrer suspension delay time. The grace time can be arbitrarily set as an agitator stop time over (not shown), and is determined by the characteristics of the slurry or chemical solution to be handled and the driving speed of the stock solution circulation pump 4 (circulation flow rate in the circulation line 6 up to the use point 5). Therefore, it is desirable to perform optimization by conducting a verification test in advance. 9 is a liquid amount of the drum 2, and 18 and 19 are liquid amount sensors.

  FIG. 3 shows a normal operation state after completion of the transfer process and the drum switching operation. The process display 1 of the drum 1 is empty, and the process display 2 of the drum 2 is in use. Thereafter, the valves 3-2 and 3-4 are opened, the valves 3-1 and 3-3 are closed, and the drum 2 is used for normal operation.

  4 to 8 are diagrams showing other embodiments of the present invention. FIG. 4 is a schematic diagram showing a normal process before the transfer control is activated, and FIG. 5 is a schematic diagram showing a transfer preparation process. 6 is a schematic diagram showing a normal process, FIG. 7 is a schematic diagram showing a transfer process, and FIG. 8 is a schematic diagram showing a transfer process and a normal process after drum switching. The following steps are all performed by adjusting the control function of the slurry controller 17.

  In FIG. 4, the process display 22 of the drum 1 is “in use”, and the process display 23 of the drum 2 is “usable”, that is, the drum 1 is ready for use after it is empty. The combination of drums 1 and 2 and “in use” and “usable” is determined by the drum that is being used at that moment, and is reversed in accordance with drum switching. When the circulation pump 4 is operated with the valves 31 and 3-3 open and the valves 3-2 and 3-4 closed, the slurry or chemical liquid in the drum 1 passes through the circulation line 6 to the use point. Return to drum 1. At the use point, the slurry or chemical in the system is consumed by opening the valve 3-5 at an arbitrary timing. At this time, the agitators 7 and 7 of the drums 1 and 2 continue the agitation operation and have a role of maintaining a uniform state of the slurry or the chemical solution.

  FIG. 5 shows a transfer preparation process. The process indications 22 and 23 of the drum 1 and the drum 2 are in use / preparation for transfer and ready for use / preparation for transfer, respectively. In FIG. 4, when the use point 5 slurry is continuously consumed and reduced, the liquid amount 8 of the drum 1 is kept below the transfer preparation start level 21 and above the drum empty level 11 for a certain period of time. Starts. At the time of the transfer preparation process, the circulation pump 4 is operated with the valves 3-2 and 3-3 open and the valves 31 and 3-4 closed, so that the slurry or the chemical solution in the drum 2 is used at the use point 5. It returns to the drum 1 via the circulation line 6. Even during the transfer preparation process, the supply of the slurry or the chemical liquid to the use point 5 is continued and can be arbitrarily used by opening and closing the valve 3-5. During the transfer preparation step, the liquid amount 9 of the drum 2 that was originally full is continuously reduced because it is sent to the drum 1, and the liquid amount 9 of the drum 2 is less than the standby side drum transfer preparation completion level 20 and the drum empty level 11. This is continued until the above state is maintained for a predetermined time or longer. On the other hand, since the liquid amount 8 of the drum 1 continues to increase, even if the liquid amount 9 of the drum 2 does not decrease to less than the standby-side drum transfer preparation completion level 20, the liquid amount 8 of the drum 1 reaches the transfer reception stop level 16. At this point, an overflow prevention interlock is provided so that the transfer preparation process is completed.

  After the transfer preparation process is completed, the normal operation state shown in FIG. 6 is restored, and the process indications 22 and 23 of the drum 1 and the drum 2 are returned to being usable during use. When the circulation pump 4 is operated with the valves 3-1 and 3-3 open and the valves 3-2 and 3-4 closed, the slurry or chemical liquid in the drum 1 passes through the circulation line 6 to the use point. Then, the state returns to the drum 1.

  FIG. 7 shows the transfer process. The process indications 22 and 23 of the drum 1 and the drum 2 are in use / transferring and available / transferring, respectively. As a result of the continuous consumption of the slurry at the use point 5, when the liquid amount 8 of the drum 1 is kept below the stirrer stop level (transfer start level) 10 and above the drum empty level 11, the stirrer 7 Stops and the transfer process starts. At the time of the transfer process, the circulating pump 4 is operated with the valves 3-11 and 3-4 open and the valves 3-2 and 3-3 closed, so that the slurry or chemical in the drum 1 can be used at the use point 5. Is transferred to the drum 2 via the circulation line 6. During the transfer process, the supply of the slurry or the chemical liquid to the use point 5 is continued, and can be arbitrarily used by opening and closing the valve 3-5. The transfer process continues to decrease because the liquid amount 8 of the drum 1 is sent to the drum 2, drops below the drum empty level 11, and then continues for the time of the drum empty transfer continuation timer (not shown). The drum 1 is empty. At this time, the remaining amount of slurry in the drum 1 is reduced to the limit of the amount of liquid that the insert tube 12 can physically suck. On the other hand, since the liquid amount 9 of the drum 2 continues to increase, even when the liquid amount 8 of the drum 1 does not fall below the drum empty level 11, when the liquid amount 9 of the drum 2 reaches the transfer receiving stop level 16, An interlock for preventing overflow is provided so that the transfer process is completed. Further, since the stirrer is stopped during the transfer process and the ability to maintain the uniform state of the slurry or the chemical solution is reduced, an interlock is provided when the transfer process exceeds the stirrer suspension delay time. The grace time can be arbitrarily set as a stirrer stop time over (not shown), and is determined by the characteristics of the slurry or chemical solution to be handled and the driving speed of the stock solution circulation pump 4 (circulation flow rate in the circulation line 6 up to the use point). Therefore, it is desirable to perform optimization by conducting a verification test in advance.

  FIG. 8 shows a normal operation state after completion of the transfer process and the drum switching operation. The process display 22 of the drum 1 is empty, the process display 23 of the drum 2 is in use, and the drum 2 is in a normal operation state.

  In any of the above embodiments 1 and 2, the present invention can be carried out without using the stirrers 7 and 7.

  Next, examples of the present invention will be described. However, the present invention is not limited to these examples.

<Example 1>
It implemented according to the process shown in FIGS. The set values were as follows.
Target fluid: JSR CMS7552
Properties of the fluid: Colloidal silica is contained as a main component of the abrasive grains, and the sedimentation property is low, but it is expensive.
4: Circulation pump: PC-10MB bellows pump manufactured by Nippon Pillar Industries, flow rate 3.5 liters / min 10: Stirrer stop level (transfer start level) 30% (arbitrary value because the stirrer is not installed)
11: 5% drum empty level
12, 14: Insert tube tip position 5 mm from the bottom of the drum
16: Transfer acceptance stop level 90% (setting not to perform transfer preparation process)
20: standby side drum transfer preparation completion level 90% (setting not to perform transfer preparation process)
21: Transfer preparation start level 40% (setting not to perform transfer preparation process)
Drum empty transfer continuation timer 145 seconds Stirrer stop time over 0 min (setting disabled)
Stirrer 7, 7: Not used.

  In Example 1, the drum empty level was set to 5% before the present invention was applied. On the other hand, after application, the remaining amount of slurry could be further reduced by 4% by the drum continuation transfer timer function. As a result, in this example, the remaining amount of slurry could be reduced from 10 liters to 1.5 liters. In addition, the amount of fluid fluid in the drum is expressed as 100% (hereinafter the same).

<Example 2>
It implemented according to the process shown in FIGS. The set values were as follows.
Target fluid: Ceria slurry (HS-DLS) manufactured by Hitachi Chemical Co., Ltd.
Properties of the fluid: Since ceria (CeO2) having a high specific gravity is contained as a main component of the abrasive grains, the sedimentation property of the solid component is high. The settling speed is out of spec (5.0 ± 0.1 wt%) 120 minutes after the stirrer is stopped.
4: Circulation pump PC-10MB bellows pump manufactured by Nippon Pillar Industry, flow rate 3.5 liters / min 7, 7: Air-driven air-driven stirrer, rotation speed 350 rpm, blade diameter 12 cm, shaft length is 255 at the liquid level Is exposed to the liquid surface 10: Stirrer stop level (transfer start level) 30%
16: Transfer stoppage level 100%
20: Standby side drum transfer preparation completion level 70%
21: Transfer preparation start level 40%
11: 5% drum empty level
Drum emptying transfer continuation timer 145 minutes Stirrer stop time over 120 minutes 12, 14: Insert tube tip position 5 mm from drum bottom surface

According to Example 2, the following results were obtained.
1) In Example 2, before applying the present invention, the drum empty level was set to a height of 25% at which the stirring blades were exposed. On the other hand, after application, it was possible to lower the height to 5%, and furthermore, the remaining amount of slurry could be further reduced by 4% by the drum continuation transfer timer function. As a result, in Example 2, the remaining amount of slurry could be reduced from 50 liters to 1.5 liters.
2) Further, according to the second embodiment, after the stirrer 7 is stopped at the time when the stirrer stop level (transfer start level) 10 is 30%, it takes less than 18 minutes after the drum emptying and transfer continuation timer expires. Cost. This was able to clear the limitation that the solid content concentration was within 120 minutes of specifying out due to sedimentation.
3) Furthermore, according to Example 2, 14: Stirrer stop level (transfer start level) 10 was set to 30%. As a result, it was possible to prevent scattering of liquid due to rotation of the stirring blade in the vicinity of the liquid surface and subsequent fixation drying.

  INDUSTRIAL APPLICABILITY The present invention can be used in a slurry supply method and apparatus for supplying a slurry such as a polishing liquid or a chemical liquid used in a CMP process in a semiconductor manufacturing process to a use point using two or more slurry supply tanks.

1: Drum 1
2: Drum 2
3-1 to 3-5: Valve 4: Circulation pump 5: Use point 6: Circulation line 7: Stirrer 8: Liquid amount of drum 1 9: Liquid amount of drum 2 10: Stirrer stop level (transfer start level)
11: Drum empty level 12-15: Insert tube 16: Transfer receiving stop level 17: Slurry control unit 18, 19: Liquid quantity measurement sensor 20: Standby side drum transfer preparation completion level 21: Transfer preparation start level 22: Process display ( In use drum)
23: Process display (standby drum)

Claims (10)

A slurry supply tank in use, one or more standby slurry supply tanks, a sensor for measuring the amount of liquid in each slurry supply tank, a slurry circulation line from each slurry supply tank to the use point, Slurry circulation pump, switching valve for each slurry supply tank, and a slurry supply tank that is on standby by a switching valve for each slurry supply tank in the return line after passing through the circulation line from the slurry supply tank in use to the use point And a slurry control unit for continuously supplying slurry to the point of use,
1) A normal process of supplying and circulating the slurry in the slurry supply tank in use to a use point through a circulation line by a slurry circulation pump;
2) When the amount of liquid in the slurry supply tank in use reaches the transfer start level, the switching valve is switched, and the slurry in the slurry supply tank in use is transferred to the use point via the circulation line by the slurry circulation pump. The slurry supply tank in use is emptied by repeating the supply and circulation and the transfer step of transferring substantially the entire amount of slurry remaining in the slurry supply tank in use to the slurry supply tank in standby. Before stopping the supply to the point of use, the slurry remaining in the slurry supply tank in use can be quickly transferred to the slurry supply tank in standby to reduce the remaining amount of the slurry supply tank in use. A slurry supply method characterized by having a function to perform.   A slurry supply tank in use, one or more standby slurry supply tanks, a sensor for measuring the amount of liquid in each slurry supply tank, a slurry circulation line from each slurry supply tank to the use point, Slurry circulation pump, switching valve for each slurry supply tank, and a slurry supply tank that is on standby by a switching valve for each slurry supply tank in the return line after passing through the circulation line from the slurry supply tank in use to the use point And a slurry control unit for continuously supplying the slurry to the point of use, and implementing the method according to claim 1. A slurry supply tank in use, one or more standby slurry supply tanks, a sensor for measuring the amount of liquid in each slurry supply tank, a slurry circulation line from each slurry supply tank to the use point, Slurry circulation pump, switching valve for each slurry supply tank, and a slurry supply tank that is on standby by a switching valve for each slurry supply tank in the return line after passing through the circulation line from the slurry supply tank in use to the use point And a slurry control unit for continuously supplying slurry to the point of use,
1) A normal process of supplying and circulating the slurry in the slurry supply tank in use to a use point through a circulation line by a slurry circulation pump;
2) When the amount of liquid in the slurry supply tank in use reaches the transfer preparation start level, the slurry in the slurry supply tank on standby by the slurry circulation pump is changed to the slurry supply tank in use by switching the circulation line. A transfer preparation step that reversely transfers, prevents the capacity of the slurry supply tank in a standby state from being exceeded, and increases the degree of freedom of the transfer amount;
3) When the amount of liquid in the slurry supply tank on standby reaches the level ready for transfer, the slurry in the slurry supply tank in use is supplied again to the use dropper by switching the circulation line by the slurry circulation pump. Normal process to do,
4) When the amount of liquid in the slurry supply tank in use reaches the transfer start level, the switching valve is switched, and the slurry in the slurry supply tank in use is transferred to the use point via the circulation line by the slurry circulation pump. The slurry supply tank in use is emptied by repeating the supply and circulation and the transfer step of transferring substantially the entire amount of slurry remaining in the slurry supply tank in use to the slurry supply tank in standby. Before stopping the supply to the point of use, the slurry remaining in the slurry supply tank in use can be quickly transferred to the slurry supply tank in standby to reduce the remaining amount of the slurry supply tank in use. A slurry supply method characterized by having a function to perform.   A slurry supply tank in use, one or more standby slurry supply tanks, a sensor for measuring the amount of liquid in each slurry supply tank, a slurry circulation line from each slurry supply tank to the use point, Slurry circulation pump, switching valve for each slurry supply tank, and a slurry supply tank that is on standby by a switching valve for each slurry supply tank in the return line after passing through the circulation line from the slurry supply tank in use to the use point And a slurry control unit for continuously supplying the slurry to the point of use, and implementing the method according to claim 3.   The slurry supply tank is equipped with a stirrer, the transfer start level is set at the position of the stirring blade of the stirrer, and the agitator is stopped before the liquid level of the slurry supply tank in use falls below the height of the stirring blade, The slurry remaining in the slurry supply tank in use is immediately transferred to the standby slurry supply tank without stopping the supply to the point of use, preventing the liquid from splashing and the subsequent fixed drying. The slurry supply method according to claim 1, further comprising a function of reducing the amount of remaining slurry in the slurry supply tank in use.   A weight strain sensor is used as the sensor, and the liquid volume of the slurry is continuously monitored, and the liquid volume at which transfer control starts or ends is freely set or changed by inputting a liquid volume signal to the control unit. The slurry supply method according to claim 1, wherein the slurry supply method has a function capable of.   The slurry control unit has a timer function in which the transfer operation ends after a set time after the amount of liquid in the slurry supply tank falls below the transfer end set value, and the suction tube tip sufficiently immerses the transfer end set value. By setting the amount and optimizing the timer, the switching failure of the slurry supply tank caused by the manufacturing error of the suction tube and the slurry supply tank, the error of attaching the suction tube, the reading error of the liquid amount measurement sensor, etc. The slurry supply method according to claim 1, wherein the remaining slurry amount is further reduced by making it unnecessary to secure the margin.   The slurry supply method according to claim 1, wherein the slurry control unit has a safety mechanism that prevents a capacity overflow of the slurry liquid amount by setting an upper limit of the slurry liquid amount.   The slurry control unit automatically recognizes that only one slurry supply tank is set, and does not perform the transfer preparation process and the transfer process, and a new slurry supply tank can be set and used. 4. The slurry supply method according to claim 1, wherein the transfer preparation step and the transfer step are controlled to be started as soon as the state is confirmed.   In the slurry control, when the slurry supply tank involved in the operation is removed during the transfer preparation step or the transfer step, the transfer preparation step or the transfer step is immediately stopped and the removed slurry supply is removed. The slurry supply method according to claim 1 or 3, which has a function of notifying that the tank has become empty.

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