JP2016063058A - Centering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a wafer may be bent or missed, because a guide, or the like, is pushed mechanically against a guide, or the like, when centering the wafer.SOLUTION: A centering device 1 includes a gas supply section 11 for supplying gas, and a wafer guide 12 including a circular bottom face 12a having an outlet 12c of the gas supplied by the gas supply section 11, and a side face extending upward from the outer edge of the bottom face 12a, and having such a shape as the inner diameter increases upward. The wafer 2 is centered when the gas supplied by the gas supply section 11 passes between the outer peripheral edge of a circular wafer 2 floating in the wafer guide 12, and the side face 12b of the wafer guide 12. As a result, the wafer 2 can be centered without being impaired.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a centering apparatus for centering a circular wafer.

  Conventionally, in a semiconductor manufacturing process, an aligner device is used to align a wafer, and the aligner device sometimes performs wafer centering. The centering of the wafer is usually performed by mechanically bringing a guide or the like into contact with the side surface (edge) of the wafer from a plurality of directions. (For example, refer to Patent Document 1).

JP 2000-286325 A

  However, the conventional aligner apparatus mechanically presses a guide or the like against the wafer, and there is a problem that the wafer may be bent or broken by the force.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an apparatus capable of centering a wafer without mechanically bringing a guide or the like into contact with the wafer.

In order to achieve the above object, a centering device according to the present invention includes a gas supply unit for supplying gas, a circular bottom surface having a gas outlet supplied by the gas supply unit, and an upper edge from the outer edge of the bottom surface. And a wafer guide including a side surface having a shape with an inner diameter increasing toward the top, and the outer periphery of the circular wafer in which the gas supplied by the gas supply unit is floating in the wafer guide; The wafer is centered by passing between the side surfaces of the wafer guide.
With such a configuration, the wafer is held at the center position of the wafer guide by the gas passing between the outer peripheral edge of the wafer and the side surface of the wafer guide, and the guide or the like is mechanically brought into contact with the wafer. The centering of the wafer can be realized without causing it. As a result, the possibility of damaging the wafer during centering can be reduced.

The centering device according to the present invention may further include a non-contact suction pad that sucks the wafer in the wafer guide in the bottom direction while floating.
With such a configuration, it is possible to suppress wafer vibration due to gas blowing.

In the centering device according to the present invention, the suction pad further includes an elevating part that raises and lowers the suction pad in a direction perpendicular to the bottom surface of the wafer guide, and sucks the wafer when the gas supply part supplies gas. The wafer may be centered by being moved toward the bottom by the elevating unit.
As the wafer approaches the bottom surface of the wafer guide, the gap between the outer peripheral edge of the wafer and the side surface of the wafer guide becomes narrower. Therefore, with such a configuration, the wafer can be centered with higher accuracy by moving the wafer toward the bottom surface.

In the centering device according to the present invention, the area of the bottom surface of the wafer guide may be smaller than the area of the wafer to be centered.
With such a configuration, for example, when the wafer is moved toward the bottom surface of the wafer guide, the height of the wafer becomes narrower between the outer peripheral edge of the wafer and the side surface of the wafer guide. Therefore, the wafer can be centered with high accuracy at that height.

  According to the centering device of the present invention, wafer centering can be realized without mechanical contact with the side surface of the wafer.

Sectional schematic diagram showing the configuration of the centering device according to the embodiment of the present invention The perspective view of the centering apparatus by the same embodiment Vertical sectional view showing a gap between a wafer and a wafer guide in the same embodiment The figure for demonstrating the centering of the wafer in the embodiment

  Hereinafter, a centering device according to the present invention will be described using embodiments. Note that, in the following embodiments, the components given the same reference numerals are the same or equivalent, and repetitive description may be omitted. A centering device according to an embodiment of the present invention will be described with reference to the drawings. The centering apparatus according to the present embodiment is for centering a floating wafer using a gas.

FIG. 1 is a schematic cross-sectional view showing a centering device 1 according to the present embodiment, and FIG. 2 is a perspective view of the centering device 1. The centering device 1 is for centering the wafer 2 and may be used for centering the wafer 2 in an aligner device, for example.
In FIG. 1, the centering device 1 according to the present embodiment includes a gas supply unit 11, a wafer guide 12, a suction pad 13, and an elevating unit 14.

  The gas supply unit 11 supplies gas. The gas is usually air, but may be the atmospheric gas when the centering device 1 is installed in a predetermined chamber or the like. Moreover, the gas supply part 11 may supply other gas. The gas supply part 11 is realizable by a ventilation means, for example. Moreover, the gas supplied by the gas supply part 11 may be supplied to the wafer guide 12 via the vent pipe 11a, as FIG. 1 shows. Note that the flow rate of the gas supplied by the gas supply unit 11 is usually constant, but may vary depending on the height of the suction pad 13 and the like.

  The wafer guide 12 includes a bottom surface 12a and a side surface 12b. The bottom surface 12 a has a circular shape and has a gas outlet 12 c supplied by the gas supply unit 11. The outlet 12c may be constituted by a plurality of holes, and may be annular or arcuate. The outlets 12c are preferably equally distributed on the circumference with respect to the center of the bottom surface 12a. In addition, when a plurality of outlets 12c are provided on the bottom surface 12a, it is preferable that the gas with the same flow rate is blown out from each outlet 12c. The side surface 12b extends upward from the outer edge of the bottom surface 12a and is configured to surround the outer edge. The side surface 12b has a shape in which the inner diameter increases toward the upper side. That is, the side surface 12b is a mortar-shaped wall surface surrounding the bottom surface 12a. Note that the cross section of the side surface 12b in a plane parallel to the bottom surface 12a is circular, and the circular cross-sectional shape and the bottom surface 12a are preferably concentric when viewed from a direction perpendicular to the bottom surface 12a. It is. FIG. 3 is a longitudinal sectional view in a plane passing through the center of the bottom surface 12 a, showing a gap between the wafer 2 and the wafer guide 12. Although FIG. 3 shows the case where the inner surface of the side surface 12b (the surface on the wafer 2 side) is a straight line, this need not be the case. For example, the inner surface of the side surface 12b may be curved in a bowl shape so that the degree of increase in diameter becomes smaller toward the upper side. Further, the area of the bottom surface 12a may or may not be smaller than the area of the wafer 2 to be centered. Further, an angle formed between the wafer 2 and the side surface 12b at a height at which the wafer 2 is centered (as shown in the longitudinal sectional view of FIG. 3, normally, an angle formed between a plane parallel to the bottom surface 12a and the side surface 12b). For example) may be about 45 degrees, smaller than 45 degrees, or other angles. When the angle is close to 90 degrees, the angle is preferably smaller than 60 degrees and smaller than 45 degrees from the viewpoint that the wafer 2 is easily vibrated by the gas flowing along the side surface 12b. Further preferred. The angle may be in the range of 30 to 45 degrees, for example.

  The suction pad 13 is a non-contact suction pad that sucks the wafer 2 in the wafer guide 12 toward the bottom surface in a floating state. The suction pad 13 sucks the wafer 2 without contacting the wafer 2 by blowing the supply air from the nozzle. The suction method of the suction pad 13 may be, for example, a Bernoulli method or a cyclone method. The suction pad 13 is already known and will not be described in detail.

  The elevating unit 14 elevates and lowers the suction pad 13 in a direction perpendicular to the bottom surface 12a of the wafer guide 12, that is, in the direction of the double arrow in FIG. The raising / lowering mechanism does not matter. The elevating unit 14 may have, for example, a rack and pinion or a ball screw. The elevating unit 14 having a rack and pinion may elevate and lower the suction pad 13 connected to the rack, for example, by rotating the pinion with a motor or the like. The elevating unit 14 having a ball screw may elevate and lower the suction pad 13 connected to the nut, for example, by rotating a screw shaft by a motor or the like.

Next, a method for centering the wafer 2 by the centering apparatus 1 according to the present embodiment will be described.
The wafer 2 placed on the wafer guide 12 is held by the suction pad 13 so as to float at a certain distance from the suction pad 13. Further, the elevating unit 14 raises the suction pad 13. At that time, the suction pad 13 may be raised in a range where the wafer 2 does not exceed the upper end of the side surface 12b. In such a situation, when the gas from the gas supply unit 11 is supplied to the bottom surface 12a of the wafer guide 12 through the vent pipe 11a and the outlet 12c, the gas is supplied to the wafer guide as shown in FIG. 12 passes between the outer peripheral edge of the wafer 2 floating inside and the side surface 12b of the wafer guide 12 and is discharged. As such, since the discharged gas flows along the side surface 12b and creates a gap between the side surface 12b and the wafer 2, the wafer 2 does not come into contact with the side surface 12b while the gas is supplied. . In such a situation, for example, as shown in FIG. 4, when the wafer 2 is biased in a certain direction from the center of the wafer guide 12, the outer peripheral edge of the wafer 2 is located at the position of the wafer guide 12 where the wafer 2 is offset. And the area between the side surface 12b is reduced, and the pressure of the gas supplied from the gas supply unit 11 is increased. On the other hand, at the location of the wafer guide 12 where the wafer 2 is separated, the area between the outer peripheral edge of the wafer 2 and the side surface 12b increases, and the pressure of the gas supplied from the gas supply unit 11 decreases. As a result, a force from the higher pressure side to the lower side acts on the wafer 2, and the wafer 2 moves to the center of the wafer guide 12 as indicated by an arrow in FIG. 4. In this way, the wafer 2 is centered.

  When the gas is supplied by the gas supply unit 11, the elevating unit 14 moves the suction pad 13 that is sucking the wafer 2 toward the bottom surface 12 a. As a result, the gap between the outer peripheral edge of the wafer 2 and the side surface 12b is narrowed, and the wafer 2 is centered with higher accuracy. Note that the suction pad 13 may be moved by the elevating unit 14 within a range in which there is a gap through which the supplied gas can pass between the wafer 2 sucked by the suction pad 13 and the side surface 12b. Is preferred. Therefore, how far the movement is performed may be determined according to the diameter of the wafer 2 and the inclination of the side surface 12b. When the wafer 2 is moved toward the bottom surface 12a, the gap between the outer peripheral edge of the wafer 2 and the side surface 12b is reduced. As a result, it is possible to realize centering with higher accuracy than performing centering in a state where the gap between the two is large. In addition, after the centering is performed, the gas supply from the gas supply unit 11 may be stopped.

  In order to perform a series of processes as described above, the centering device 1 may include a control unit (not shown) that controls each component. For example, the control unit first controls the elevating unit 14 to move the wafer 2 upward in a situation where the wafer 2 to be centered is sucked by the suction pad 13. Alternatively, the suction pad 13 may be lifted in advance, and the wafer 2 may be sucked by the suction pad 13. Next, the control unit starts the gas supply by the gas supply unit 11, and lowers the wafer 2 to a predetermined position by the elevating unit 14 when the gas supply continues. In this way, the wafer 2 can be centered.

  As described above, according to the centering device 1 according to the present embodiment, centering of the wafer 2 can be realized without physically bringing a guide or the like into contact with the wafer 2. As a result, the possibility of damaging the wafer 2 during centering can be reduced. Further, by performing centering in a state where the wafer 2 is sucked by the non-contact suction pad 13, it is possible to prevent the wafer 2 from vibrating due to the gas supplied from the gas supply unit 11. Further, when centering is performed while lowering the wafer 2 having a diameter larger than the diameter of the bottom surface 12a of the wafer guide 12 toward the bottom surface 12a, the centering with high accuracy is performed by lowering the wafer 2 to an appropriate position. Can be realized. Further, when the diameter of the wafer 2 is larger than the diameter of the bottom surface 12a of the wafer guide 12, even if the wafer 2 does not float due to an unexpected situation, the surface of the wafer 2 contacts the bottom surface 12a and is damaged. Can be avoided.

  In the present embodiment, the case where the area of the bottom surface 12a of the wafer guide 12 is smaller than the area of the wafer 2 to be centered has been mainly described, but this need not be the case. For example, the area of the bottom surface 12a of the wafer guide 12 may be substantially the same as or larger than the area of the wafer 2 to be centered. Even in the latter case, it is preferable that the area of the bottom surface 12 a is not so much larger than the area of the wafer 2.

  In the present embodiment, the case where the centering of the wafer 2 is performed by the elevating unit 14 lowering the suction pad 13 has been described, but this need not be the case. The wafer 2 held at a certain height may be centered by the gas supplied from the gas supply unit 11 without moving the suction pad 13. In that case, the centering device 1 may not include the elevating unit 14.

  Further, in the present embodiment, the case where the wafer 2 is centered in a state where the wafer 2 is sucked in the direction of the bottom surface 12a by the non-contact suction pad 13 has been described. For example, when the wafer 2 to be centered can be appropriately suspended in the wafer guide 12 by the gas supplied from the gas supply unit 11, the wafer 2 is centered without using the suction pad 13. Also good. For example, when the gas supplied from the gas supply unit 11 accumulates between the wafer 2 and the bottom surface 12a, the wafer 2 can be floated. In that case, the centering device 1 may not include the suction pad 13.

  Moreover, although the case where gas was sent via the vent pipe 11a from the gas supply part 11 to the blower outlet 12c was demonstrated in this Embodiment, it may not be so. For example, a chamber capable of containing gas is provided on the back surface side of the bottom surface 12a, and the gas supply unit 11 supplies gas to the chamber, and the gas in the chamber is a plurality of holes provided in the bottom surface 12a. It may be supplied to the inside of the wafer guide 12 through a certain outlet 12c.

  Further, the present invention is not limited to the above-described embodiment, and various modifications are possible, and it goes without saying that these are also included in the scope of the present invention.

  As described above, according to the centering device of the present invention, the effect that the wafer can be centered without damaging the wafer is obtained, and it is useful, for example, as a device for centering the wafer in the alignment device.

DESCRIPTION OF SYMBOLS 1 Centering apparatus 2 Wafer 11 Gas supply part 12 Wafer guide 12a Bottom face 12b Side face 13 Suction pad 14 Lifting part

Claims (4)

A gas supply unit for supplying gas;
A wafer guide including a circular bottom surface having a gas outlet supplied by the gas supply unit, and a side surface extending upward from the outer edge of the bottom surface and having a shape with an inner diameter increasing toward the upper side. Prepared,
The gas supplied by the gas supply unit passes between the outer peripheral edge of the circular wafer floating in the wafer guide and the side surface of the wafer guide, whereby the wafer is centered. Centering device. The centering device according to claim 1, further comprising a non-contact suction pad that sucks the wafer in the wafer guide in a bottom surface direction in a floating state. An elevating part that elevates and lowers the suction pad in a direction perpendicular to the bottom surface of the wafer guide;
The wafer is centered by moving the suction pad that sucks the wafer toward the bottom surface by the elevating part when the gas supply unit supplies gas. Centering device. The centering apparatus according to any one of claims 1 to 3, wherein an area of a bottom surface of the wafer guide is smaller than an area of a wafer to be centered.

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