JP2011143508A - Liquid mixture supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid mixture supply device which prevents drying from an overflow line in a tank in which a liquid mixture (slurry) is stored, and prevents the cohesion of abrasive grains in the tank. <P>SOLUTION: The liquid mixture supply device includes a supply tank storing the liquid mixture supplied to a machining device, a first liquid mixture supply path for supplying the liquid mixture stored in the supply tank to the machining device, a supply tank overflow path abolishing the liquid mixture when the liquid mixture stored in the supply tank increases over specified amount, and a water sealing means arranged in the tank overflow path. The water sealing means a water sealing box formed with an inflow hole into which the liquid mixture overflowing from the supply tank flows on an upper wall, a water sealing cylinder discharging the liquid mixture in the water sealing box, and a water sealing lid covering the upper end of the water sealing cylinder. A liquid supplying path introducing liquid which does not include abrasives into the liquid mixture collected in the water sealing box is connected to the water sealing box. <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.

  Such a mixed liquid supply apparatus includes a storage tank that stores the mixed liquid. However, it is important that the mixed liquid always has a uniform concentration in the storage tank.

Japanese Patent Laid-Open No. 10-329909

  However, the storage tank that stores the liquid mixture (slurry) is not normally sealed due to reasons such as the fact that it is not normally sealed lid or the drain pipe is connected, so the atmosphere inside the tank dries and mixes with the tank side wall etc. Liquid abrasive grains may agglomerate and adhere.

  When the abrasive grains fixed to the tank side wall are peeled off and mixed into the liquid mixture and supplied to the polishing device, scratches called scratches occur on the surface to be polished during polishing, or the nozzle that supplies the liquid mixture during polishing There was a problem of causing abrasive clogging.

  As measures against these problems, in order to prevent drying in the tank, measures such as supplying the mixed solution to the tank faster than the agglomeration rate or spraying the mixed solution with a spray nozzle have been taken.

  However, these countermeasures cause new problems such as waste of storing a large amount of unnecessary liquid mixture, concentration change of liquid mixture due to mist spraying, and cost increase due to addition and control of spray nozzles.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a mixed liquid supply apparatus capable of stably supplying a mixed liquid having a constant concentration of abrasive grains and liquid to a processing apparatus. It is to be.

  According to the present invention, there is provided 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, the supply tank storing the mixed liquid supplied to the processing apparatus, and the supply tank A first mixed liquid supply path for supplying the mixed liquid stored in the processing apparatus to the processing device, and a supply tank overflow path for discarding the mixed liquid when the mixed liquid stored in the supply tank exceeds a specified amount And a sealing means disposed in the supply tank overflow path, and the sealing means includes a sealing box having an upper wall formed with an inflow hole through which the mixed liquid overflowed from the supply tank flows. A sealing cylinder for discharging the liquid mixture in the sealed water box provided so as to penetrate the bottom wall of the sealed water box and project into the sealed water box, and the side wall or the upper wall of the sealed water box Attached to the seal A reverse concave sealing lid that is covered with a predetermined gap so as to cover the upper end of the cylinder and is covered with the upper part of the sealing cylinder, and the sealing lid is an upper end of the sealing cylinder. And a liquid supply path for introducing a liquid containing no abrasive to the liquid mixture stored in the sealed water box is connected to the sealed water box so as to overlap with the vertical direction. Provided is a mixed liquid supply apparatus.

  Preferably, the liquid mixture supply device includes a dilution tank that mixes the liquid and the abrasive to a predetermined concentration to create a liquid mixture, a second liquid mixture supply path that supplies the liquid mixture from the dilution tank to the supply tank, and dilution. A dilution tank overflow path is further provided for discarding the mixed liquid when the mixed liquid stored in the tank exceeds a specified amount, and the dilution tank overflow path is connected to sealing means.

  Preferably, the sealing lid is configured to be attached to the side wall or upper wall of the sealing box at an arbitrary position in the vertical direction, and by changing the mounting position of the sealing lid, the sealing lid and the sealing cylinder The overlap length can be changed.

  According to the mixed liquid supply apparatus of the present invention, since the supply tank overflow path and the dilution tank overflow path are connected to the sealing means, drying from the supply tank overflow path and the overflow path of the dilution tank can be prevented, As a result, agglomeration of abrasive grains in the tank can be prevented.

  Moreover, since the overlapping length of a sealing lid and a sealing cylinder can be changed arbitrarily, the pressure in a supply tank or a dilution tank can be adjusted. In other words, increase the overlap length to ensure a sufficient sealing condition and improve the sealing performance in the tank, or reduce the overlap length to suppress pressure fluctuations in the tank. Can do.

1 is an overall configuration diagram of a mixed liquid supply apparatus according to an embodiment of the present invention. It is a longitudinal cross-sectional view of the water sealing apparatus which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the water sealing apparatus which concerns on 2nd Embodiment of this invention. FIG. 4A is a longitudinal sectional view of the sealing device of the first embodiment showing the liquid level height when the inside of the sealed box is high pressure, and FIG. 4B is the liquid when the inside of the sealed box is low pressure. It is a longitudinal cross-sectional view of the water sealing apparatus which shows surface height.

  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.

  The slurry stock solution tank 6 of the mixed solution supply apparatus 2 contains a high concentration slurry (mixed solution) 8 in which a liquid such as pure water and an abrasive such as SiC are mixed. Reference numeral 10 denotes a dilution tank. A slurry having a high concentration in the slurry stock solution tank 6 is supplied into the dilution tank 10 through a pipe line 14, and a liquid such as pure water is supplied to the dilution tank through a liquid supply path 16. 10, the slurry stock solution 8 is diluted with a liquid, and the dilution tank 10 stores the slurry (mixed solution) 8 having a diluted concentration.

  A stirring device (not shown) is installed in the dilution tank 10, and the uniform concentration in which the concentration is diluted by stirring the slurry source liquid 8 and the liquid sent through the liquid supply path 16 with this stirring device. The slurry 18 is obtained. On-off valves 20 and 22 are inserted into the pipe line 14 and the liquid supply path 16, respectively.

  From the dilution tank 10, a diluted liquid (slurry) 18 is supplied to the supply tank 12 through a pipe line (second mixed liquid supply path) 24, and the supply tank 12 stores the diluted mixed liquid 18. To do. An open / close valve 26 is inserted in the pipe line 24.

  A liquid mixture (slurry) 18 having a diluted concentration is supplied from the supply tank 12 to a polishing apparatus 4 via a pipe line (first mixed liquid supply path) 28, and a plate-like object such as a semiconductor wafer is formed by the polishing apparatus 4. Polishing is performed. An open / close valve 30 is inserted in the conduit 28.

  An overflow pipe (supply tank overflow path) 32 is connected to the supply tank 12, and the mixed liquid (slurry) 18 overflowed from the supply tank 12 is sealed with a water sealing device via the overflow pipe 32 and the inlet / outlet pipe 36. 37.

  Similarly, an overflow pipe (dilution tank overflow path) 34 is connected to the dilution tank 10, and the mixed liquid (slurry) 18 overflowing from the dilution tank 10 is sealed via the overflow pipe 34 and the introduction pipe 36. It is introduced into the water device 37.

  A liquid supply pipe 40 branched from the liquid supply path 16 is connected to the sealing water device 37, and the liquid mixture overflowed from the dilution tank 10 and the supply tank 12 is supplied to the sealing water device 37 and the liquid is supplied to the sealing water device 37. A liquid such as pure water is supplied through the supply pipe 40. A flow rate adjustment valve 42 is inserted into the liquid supply line 40.

  Next, with reference to FIG. 2, the structure of the water sealing apparatus 37 of 1st Embodiment is demonstrated. The sealing device 37 includes a sealing box 38 having an upper wall 38a, a bottom wall 38b, and a cylindrical side wall 38c. An inflow hole 39 into which the mixed liquid (slurry) overflowed from the dilution tank 10 and the supply tank 12 flows is formed in the upper wall 38a of the sealed water box 38.

  A sealing cylinder 44 that passes through the bottom wall 38 b of the sealing water box 38 and discharges the liquid mixture in the sealing water box 38 is provided so as to protrude into the sealing water box 38. The sealing tube 44 defines a drain hole 45, and the drain hole 45 communicates with the atmosphere.

  A sealing lid 46 is placed on the sealing cylinder 44 with a predetermined gap from the sealing cylinder 44 so as to cover the upper end of the sealing cylinder 44. The sealing lid 46 is composed of an upper wall 46a and a cylindrical side wall 46b, and has a reverse concave shape with its upper end closed and its lower end opened.

  The sealing lid 46 is fixed to the side wall 38c of the sealing box 38 via a bracket 48 fixed to the sealing lid 46 so that the mounting position in the vertical direction can be adjusted. That is, a long hole 50 is formed in the bracket 48. By inserting a screw 52 into the long hole 50 and fastening the screw 52 to the side wall 38c of the sealing box 38, the sealing lid 46 is moved in the vertical direction. Is attached to the side wall 38c of the sealed water box 38 so that the mounting position of the water sealing box 38 can be adjusted.

  In FIG. 2, the sealing lid 46 is attached to the side wall 38 c of the sealing box 38 with an overlap length L that overlaps the upper end portion of the sealing cylinder 44. The overlap length L can be changed by changing the fixing position of the screw 52 in the long hole 50 of the bracket 48.

  A liquid supply line 40 is connected to the side wall 38 c of the sealed water box 38, and pure water is supplied from the liquid supply line 40 into the sealed water box 38 and overflows from the dilution tank 10 and the supply tank 12. The mixed liquid (slurry) supplied into the sealed water box 38 through the inflow hole 39 is diluted. In this specification, this diluted liquid mixture is referred to as a waste liquid 41.

  Referring to FIG. 3, a longitudinal sectional view of a water sealing device 37A of the second embodiment is shown. The sealing device 37A of this embodiment is similar to the sealing device 37 of the first embodiment described above, and the mounting method of the sealing lid 46A is different from the first embodiment described above.

  In the present embodiment, the sealing lid 46A is attached to the upper wall 38a of the sealing box 38 through the bracket 48A so that the vertical mounting position can be adjusted. Since the other structure of this embodiment is the same as that of 1st Embodiment mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  Hereinafter, the operation of the mixed liquid supply apparatus 2 of the above-described embodiment will be described. The slurry 8 having a high concentration in the slurry stock solution tank 6 is supplied to the dilution tank 10 through the conduit 14, diluted with pure water supplied through the liquid supply path 16 in the dilution tank 10, and diluted. A liquid mixture (slurry) 18 is stored in the dilution tank 10.

  The liquid mixture 18 stored in the dilution tank 10 is supplied to the supply tank 12 via a pipe line 24 by driving a pump (not shown), and the liquid mixture (slurry) 18 diluted in the supply tank 12 is stored. Is done.

  The liquid mixture 18 stored in the supply tank 12 is supplied to the polishing apparatus 4 through a conduit 28 by driving a pump (not shown), and the polishing apparatus 4 mixes with a workpiece such as a polishing pad and a wafer. The workpiece is polished while supplying the liquid (slurry).

  When the mixed liquid 18 is stored in the supply tank 12 in a predetermined amount or more, the mixed liquid 18 is introduced into the sealing box 38 of the sealing device 37 through the overflow pipe 32 and the introduction pipe 36. Similarly, when the liquid mixture 18 stored in the dilution tank 10 reaches a specified amount or more, the liquid mixture 18 enters the sealing box 38 of the sealing device 37 via the overflow pipe 34 and the introduction pipe 36. be introduced.

  Pure water is introduced into the sealed water box 38 of the water sealing device 37 through the liquid supply pipe 40, and the mixed liquid overflowing from the supply tank 12 and the dilution tank 10 is diluted with this pure water, and sealed water Diluted waste liquid 41 is stored in the box 38.

  Since the dilution tank 10 and the supply tank 12 are disconnected from the atmosphere by the waste liquid 41 stored in the sealed water box 38, the atmosphere is introduced into the tanks 10 and 12 through the overflow pipes 34 and 32. Is prevented. As a result, the tanks 10 and 12 are always kept in a moist atmosphere, and the abrasive grains in the mixed liquid 18 are prevented from aggregating and adhering to the inner wall of the tank.

  When the pressures in the dilution tank 10 and the supply tank 12 are steady pressures, the height level H1 of the waste liquid 41 in the sealed water box 38 is approximately coincident with the upper end 44a of the sealed water tube 44 as shown in FIG. The waste liquid having the level H1 or higher is drained through the drainage hole 45 of the sealing tube 44.

  When the pressure in the dilution tank 10 and the supply tank 12 becomes a high pressure higher than the steady pressure, this high pressure is sealed through the overflow pipes 32 and 34 and the introduction pipe 36 as shown by an arrow A in FIG. Introduced in box 38.

  As a result, the waste liquid 41 in the sealed water box 38 is pushed down to a height level H2 that matches the lower end 46c of the sealed water lid 46. Even in this state, the gap between the upper end portion of the sealing tube 44 having the overlap length L and the sealing lid 46 is filled with the waste liquid 41, so that the water sealing device 37 does not break.

  On the other hand, when the pressure in the dilution tank 10 and the supply tank 12 becomes lower than the steady pressure, atmospheric pressure is introduced into the sealing lid 46 via the sealing cylinder 44 as shown in FIG. Therefore, the air in the sealed water box 38 is pushed by this atmospheric pressure and flows back in the introduction pipe 36 as shown by an arrow B. As a result, the waste liquid 41 in the sealing lid 46 is pushed down to the position of the lower end 46c of the sealing lid 46, and the level of the waste liquid in the sealing box 38 rises to H3.

  The water sealing device 37 repeats the high pressure state shown in FIG. 4A and the low pressure state shown in FIG. 4B so that the pressure in the dilution tank 10 and the supply tank 12 is converged to a steady pressure. To control.

  In the non-siphon sealing device 37, 37A as in the above-described embodiment, there is little self-cleaning action to push the deposit, and the mixed solution (slurry) may be precipitated in the sealing box 38, but the present invention. Then, since the liquid supply line 40 for supplying pure water to the sealed water box 38 is connected to the sealed water box 38, the slurry is supplied in the sealed water box 38 by constantly supplying a small amount of pure water into the sealed water box 38. In addition to being diluted to a very low concentration, it is easy to be drained along the water flow flowing into the drain hole 45, and the liquid mixture (slurry) is prevented from settling in the sealed water box 38.

  Further, by changing the mounting height position of the sealing lid 46, it is possible to arbitrarily adjust the pressure in the dilution tank 10 and the supply tank 12 that are in a sealed state. When the overlap length L is increased, a sealed state can be sufficiently secured to improve the sealing performance in the tank, and when the overlap length L is shortened, pressure fluctuations in the tank can be suppressed.

  In the embodiment described above, the overflow pipeline 34 of the dilution tank 10 is connected to the same sealing device as the sealing device 37 to which the overflow pipeline 32 of the supply tank 12 is connected, but is the same as the sealing device 37. Another sealing device having a structure may be provided, and the overflow pipe 34 of the dilution tank 10 may be connected to the sealing device.

2 Liquid supply device 4 Polishing device 6 Slurry stock solution tank 8 Slurry stock solution 10 Dilution tank 12 Supply tank 16 Liquid supply path 18 Mixed solution (slurry)
24 pipeline (second mixed solution supply route)
28 Pipe line (first liquid mixture supply path)
32 Overflow pipeline (supply tank overflow route)
34 Overflow pipeline (dilution tank overflow route)
37 Sealing device 38 Sealing box 40 Liquid supply line 44 Sealing tube 46 Sealing lid

Claims (3)

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 supply tank for storing a mixed liquid to be supplied to the processing apparatus;
A first mixed liquid supply path for supplying the mixed liquid stored in the supply tank to the processing apparatus;
A supply tank overflow path for discarding the mixed liquid when the mixed liquid stored in the supply tank exceeds a specified amount;
Water sealing means disposed in the supply tank overflow path,
The sealing means includes a sealing box in which an inflow hole into which the mixed liquid overflowed from the supply tank flows is formed on the upper wall, and projects into the sealing box through the bottom wall of the sealing box. A sealing tube that discharges the liquid mixture in the sealing box, and is attached to the side wall or the upper wall of the sealing box, and has a predetermined gap so as to cover the upper end of the sealing tube. And a reverse-concave sealing lid with the upper part covered by the sealing cylinder closed.
The sealing lid is placed on the sealing cylinder so as to overlap the upper end portion of the sealing cylinder in the vertical direction, and the sealing liquid contains an abrasive in the liquid mixture stored in the sealing box. A mixed liquid supply apparatus, wherein a liquid supply path for introducing a non-contained liquid is connected. A dilution tank that mixes liquid and abrasive to a predetermined concentration to create a mixture;
A second mixed solution supply path for supplying a mixed solution from the dilution tank to the supply tank;
A dilution tank overflow path for discarding the mixed liquid when the mixed liquid stored in the dilution tank exceeds a specified amount;
2. The mixed liquid supply apparatus according to claim 1, wherein the dilution tank overflow path is connected to the sealing means, or is connected to another sealing means having the same structure as the sealing means.   The watertight lid is configured to be attachable to the side wall or the upper wall of the watertight box at an arbitrary position in the vertical direction, and by changing the attachment position of the watertight lid, the watertight lid and the The mixed liquid supply apparatus according to claim 1 or 2, wherein an overlap length with the sealing cylinder is variable.

Images