JP2011173198A - Mixed liquid supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixed liquid supply device capable of accurately perceiving the remaining amount of abrasive stock solution in an abrasive stock solution tank with a simple structure. <P>SOLUTION: The mixed liquid supply device supplying a machining device with mixed liquid in which liquid and abrasive are mixed includes: a weight measuring device; the abrasive stock solution tank for storing the abrasive stock solution loaded onto the weight measuring device; a dilution tank preparing the mixed liquid by mixing the liquid with the abrasive stock solution in a predetermined concentration; a supply tank storing the mixed liquid supplied to the machining device; an abrasive stock solution supply route for supplying the abrasive stock solution from the abrasive stock solution tank to the dilution tank; a first mixed liquid supply route for supplying the mixed liquid from the dilution tank to the supply tank; a second mixed liquid supply route for supplying the mixed liquid stored in the supply tank to the machining device; a control means to which the weight measuring device is connected; and a remaining amount display means connected to the control means, and displaying the remaining amount of the abrasive stock solution in the abrasive stock solution tank. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a mixed liquid supply apparatus that supplies a mixed liquid (slurry) composed of abrasive grains and liquid to a processing apparatus such as a polishing apparatus.

  A semiconductor wafer in which a plurality of devices such as IC, LSI, etc. are defined on the surface by dividing by a dividing line, the back surface is ground by a grinding device and processed to a predetermined thickness, and then individually processed by a dividing device such as a dicing device. These devices are widely used for electric devices such as mobile phones and personal computers.

  In recent years, there has been a demand for thinner semiconductor wafers due to demands for smaller and thinner semiconductor devices. Grinding the backside of a semiconductor wafer leaves grinding strain on the backside of the wafer and lowers the device's bending strength. For the purpose of removing grinding strain caused by grinding and improving the bending strength, It has been proposed and put to practical use that the back surface of a wafer is polished by CMP (Chemical Mechanical Polishing) (see, for example, JP-A-10-329209).

  In CMP, while a mixed liquid (slurry) composed of abrasive grains and liquid is supplied between a polishing pad and a plate-like material such as a semiconductor wafer, the polishing pad and the plate-like material are relatively slid while rotating. It is accomplished by that.

  In order to carry out such CMP, a mixed liquid supply device that supplies a mixed liquid composed of abrasive grains and liquid to a processing apparatus such as a polishing apparatus is required. Also, a water jet apparatus that cuts a workpiece by spraying a mixed liquid of abrasive grains and liquid at a high pressure is provided with a mixed liquid supply apparatus that supplies the mixed liquid.

  In such a mixed solution supply device, a polishing agent stock solution mixed with a liquid with a high concentration of polishing agent is placed in the polishing agent stock solution tank, and then a diluted mixing solution having a desired concentration is automatically created. Is supplied to a processing apparatus such as a polishing apparatus.

  Therefore, if there is no remaining amount of the abrasive stock solution in the abrasive stock solution tank, it will not be possible to make a mixed solution, which will eventually lead to the shutdown of the processing equipment. It is important to accurately grasp the remaining amount of the drug stock solution.

  In the conventional mixed liquid supply device, when a plurality of liquid level sensors are mounted in the abrasive stock solution tank, and the remaining amount of the abrasive stock solution in the tank falls below the liquid level sensor mounted near the bottom of the tank, It is configured to notify the operator that the remaining amount is low by an alarm or the like.

Japanese Patent Laid-Open No. 10-329909

  In the conventional stock solution remaining amount detection mechanism in the conventional mixed solution supply apparatus described above, when the level of the abrasive stock solution is located between the liquid level sensor and the liquid level sensor, it is possible to accurately grasp the remaining amount of the abrasive stock solution. Can not. Even if the number of liquid level sensors to be installed is increased, it is difficult to accurately measure the remaining amount of the stock solution. In addition, the cost increases and the risk of failure of the liquid level sensor also increases.

  The present invention has been made in view of the above points, and the object of the present invention is to provide a mixed liquid that can accurately grasp the remaining amount of the abrasive stock solution in the abrasive stock solution tank with a simple structure. It is to provide a feeding device.

  According to the present invention, there is provided a mixed liquid supply apparatus for supplying a mixed liquid in a state in which a liquid and an abrasive are mixed to a processing apparatus, comprising: a weight measuring device; and an abrasive undiluted solution mounted on the weight measuring device. A polishing stock solution tank for storing, a dilution tank for mixing the liquid and the polishing stock solution at a predetermined concentration to create a mixed solution, a supply tank for storing the mixed solution supplied to the processing apparatus, and the polishing agent stock solution tank A polishing agent stock solution supply path for supplying a polishing agent stock solution from the dilution tank to the dilution tank, a first mixed solution supply path for supplying the mixed solution from the dilution tank to the supply tank, and a mixed solution stored in the supply tank. A second mixed solution supply path for supplying to the processing apparatus; a control unit connected to the weight measuring device; and a remaining unit that is connected to the control unit and displays the remaining amount of the abrasive stock solution in the abrasive stock solution tank. And a quantity display means. That mixture supply device is provided.

  According to the present invention, since the abrasive stock solution tank is supported by the weight measuring device, if the weight of the tank body stored in advance is subtracted from the total weight of the abrasive stock solution tank, the exact amount of the abrasive stock solution can be easily obtained. The remaining amount can be grasped.

  In this way, it is possible to always accurately predict the replenishment timing of the abrasive stock solution, and to accurately predict how much processing can be performed with the remaining abrasive stock solution. In addition, since it is possible to grasp the amount of the abrasive stock solution sent to the dilution tank side, it is possible to add a function for checking the malfunction of the concentration adjusting means on the dilution tank side.

1 is an overall configuration diagram of a mixed liquid supply apparatus according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown an overall configuration diagram of a mixed liquid supply apparatus according to an embodiment of the present invention. The liquid mixture supply apparatus indicated by reference numeral 2 supplies the polishing apparatus 4 with a liquid mixture (slurry) in which a liquid and an abrasive are mixed.

  An abrasive stock solution tank 6 of the mixed solution supply device 2 contains a high concentration abrasive stock solution 8 in which a liquid such as pure water and an abrasive such as silica are mixed. Reference numeral 10 denotes a dilution tank, and a high concentration of abrasive stock solution in the abrasive stock solution tank 6 is supplied into the dilution tank 10 through a pipe line (abrasive stock solution supply passage) 14 and also through a liquid supply passage 16. Then, a liquid such as pure water is supplied into the dilution tank 10, the stock solution 8 of the abrasive is diluted with the liquid, and the dilution tank 10 contains the slurry (mixed liquid) 8 having a diluted concentration.

  An agitator (not shown) is installed in the dilution tank 10. The agitator source liquid 8 and the liquid sent through the liquid supply path 16 are agitated by the agitator to uniformly dilute the concentration. A slurry 18 having a concentration is obtained. A pump 20 and an on-off valve 22 are inserted in the pipeline 14. On the other hand, a flow rate adjusting valve 24 is inserted into the liquid supply path 16.

  From the dilution tank 10, a diluted liquid (slurry) 18 is supplied to the supply tank 12 via a pipe line (first mixed liquid supply path) 26, and the supply tank 12 stores the diluted mixed liquid 18. To do. A pump 28 and an on-off valve 30 are inserted in the pipe line 26.

  A liquid mixture (slurry) 18 having a diluted concentration is supplied from the supply tank 12 through a pipe line (second liquid mixture supply path) 32 to the polishing apparatus 4, and a plate-like object such as a semiconductor wafer is formed by the polishing apparatus 4. Polishing is performed. A pump 34 and an on-off valve 36 are inserted in the pipe line 32.

  The abrasive stock solution tank 6 is mounted on the weight measuring device 38. Similarly, the dilution tank 18 is also mounted on the weight measuring device 40. The weight measuring devices 38 and 40 are connected to a control means (controller) 42.

  The weight of the abrasive stock solution tank 6 main body is stored in advance in the memory of the control means 42, and the control means 42 calculates the tank body from the total weight of the abrasive stock solution tank 6 including the abrasive stock solution 8 measured by the weight measuring device 38. Thus, the exact remaining amount of the abrasive stock solution 8 can be calculated, and the remaining amount of the abrasive stock solution is displayed on the remaining amount display means 44 such as a liquid crystal display.

  In the supply tank 12, a plurality of liquid level sensors 46a, 46b, 46c, 46d are installed. The liquid level sensors 46a to 46d are connected to the control means 42. When the liquid level of the mixed liquid (slurry) 18 in the supply tank 12 comes between the liquid level sensors 46c and 46d, the liquid level sensors 46a to 46d are opened and closed by the control means 42. The valve 30 is opened and the pump 28 is driven to supply the mixed liquid (slurry) 18 in the dilution tank 10 into the supply tank 12.

  The pumps 20, 28 and 34 are connected to the control means 42, and their driving is controlled by the control means 42. The flow rate adjusting valve 24 is also connected to the control means 42, and the supply amount of liquid such as pure water is adjusted by the flow rate adjusting valve 24 to adjust the abrasive stock solution 8 to a mixed solution (slurry) 18 having a desired concentration. .

  The remaining amount of the mixed liquid (slurry) 18 in the dilution tank 10 can be obtained by mounting the dilution tank 10 on the weight measuring device 40 in the same manner as the remaining amount of the abrasive stock solution in the abrasive stock solution tank 6. It can be easily calculated by the control means 42.

  The adjustment of the concentration of the liquid mixture (slurry) 18 in the dilution tank 10 controls the driving time of the pump 20 and the amount of liquid supplied via the flow rate adjustment valve 24, and further, the liquid mixture (slurry in the dilution tank 10). ) Based on the remaining amount of 18, the desired density can be adjusted.

  Although not particularly shown, a flowmeter is provided in the abrasive stock solution supply path 14 and the liquid supply path 16, and a liquid such as pure water supplied from the abrasive stock solution 8 and the liquid supply source 15 supplied into the dilution tank 10. By accurately measuring the amount of, the concentration of the mixed liquid (slurry) 18 in the dilution tank 10 can be adjusted more accurately.

  In the mixed liquid supply apparatus 2 of the present embodiment, since the abrasive stock solution tank 6 is supported by the weight measuring device 38, the weight of the tank body is stored in advance in the memory in the control means 42, and the control means 42 By subtracting the weight of the tank body from the total weight measured by the weight measuring device 38, the accurate remaining amount of the abrasive stock solution 8 can be easily grasped.

  As a result, it is possible to always accurately predict the replenishment timing of the abrasive stock solution 8 and to accurately predict how much processing is possible with the remaining stock solution 8. Since the amount of the abrasive stock solution 8 sent to the dilution tank 10 side can also be accurately grasped, it is possible to add a function for checking the malfunction of the concentration adjusting means on the dilution tank 10 side.

  In the above-described embodiment, the example in which the mixed liquid supply apparatus 2 of the present invention is connected to the polishing apparatus 4 has been described. However, the mixed liquid supply apparatus of the present invention is not limited to this, and a mixture of abrasive grains and liquid is used. The present invention can be similarly applied to a water jet apparatus that cuts a workpiece by injecting a liquid at a high pressure.

2 Mixture supply device 4 Polishing device 6 Abrasive stock solution tank 8 Abrasive stock solution 10 Dilution tank 12 Supply tank 16 Liquid supply path 18 Mixed solution (slurry)
14 Pipeline (Abrasive stock solution supply path)
26 Pipe line (first liquid mixture supply path)
32 pipeline (second mixed liquid supply channel)
20, 28, 34 Pump 38, 40 Weight measuring device 42 Control means 44 Remaining amount display means 46a-46d Liquid level sensor

Claims (1)

A mixed liquid supply apparatus that supplies a mixed liquid in a state where a liquid and an abrasive are mixed to a processing apparatus,
A weight measuring instrument;
An abrasive stock solution tank for storing an abrasive stock solution mounted on the weight measuring device;
A dilution tank that mixes liquid and abrasive stock solution to a predetermined concentration to create a mixed solution;
A supply tank for storing a mixed liquid to be supplied to the processing apparatus;
An abrasive stock solution supply path for supplying an abrasive stock solution from the abrasive stock solution tank to the dilution tank;
A first mixed solution supply path for supplying a mixed solution from the dilution tank to the supply tank;
A second mixed liquid supply path for supplying the mixed liquid stored in the supply tank to the processing apparatus;
Control means to which the weight measuring device is connected;
A remaining amount display means connected to the control means for displaying the remaining amount of the polishing liquid stock solution in the abrasive stock solution tank;
A mixed liquid supply apparatus comprising:

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