JP6292842B2 - Substrate holding device - Google Patents

Description

  The present invention relates to a substrate holding device, and more particularly to a substrate holding device that can generate a vortex of air at the tip of a hand and use the Bernoulli effect to hold a substrate placed on the hand.

  In recent years, with the progress of thinning of semiconductor wafers, in a substrate holding apparatus equipped with a holding mechanism such as a vacuum suction hand, the substrate suction surface and the substrate at the tip of the hand due to warping of the thin substrate and self-deflection in the substrate transport process. As a result, a gap is formed between the two, and the degree of adhesion cannot be maintained, the vacuum suction is incomplete, and there is a problem in accuracy during transportation.

  Therefore, in place of the conventional vacuum suction mechanism, compressed air is discharged from the suction surface of the suction plate to the side surface, thereby generating a negative pressure between the suction target object such as a semiconductor wafer and the like. A vacuum tweezers having a suction holding mechanism using the Bernoulli effect that floats on the plate side has been proposed (Patent Document 1).

  In addition, as a mechanism for generating negative pressure using blown air having another configuration, a vortex (swirl flow) is generated on the hand side, and the negative pressure generated thereby and the positive pressure generated between the workpiece and the holding surface There has also been proposed a hand that can balance a workpiece and hold a workpiece in a non-contact state (Patent Document 2).

JP-A-2005-74606 JP 2011-138877 A

  With the vacuum tweezers disclosed in Patent Document 1, it is possible to hold a wafer with low stress. However, as the wafer having a large diameter is held, the suction holding portion is enlarged and supplied to the inner groove. Air also needs to have a large flow rate. That is, there is a problem of an increase in capacity of the flow path and a consumption cost of compressed air.

  In the case of the non-contact holding hand which conveys a work by generating a vortex (swirl flow) disclosed in Patent Document 2, the consumption of compressed air on each suction surface is less than that of the apparatus disclosed in Patent Document 1. However, since the negative pressure generation area is limited, in order to uniformly hold a large-diameter wafer having a thin film thickness, it is necessary to arrange a large number of holding portions that generate eddy currents on the wafer suction surface, which increases the size of the workpiece. As the diameter is increased, an increase in air consumption flow rate is unavoidable as in Patent Document 1.

  Further, in the non-contact holding hand that uses the central negative pressure of the vortex as shown in Patent Documents 1 and 2, the compressed air that generated the vortex is exhausted into the gap with the wafer, so that it protrudes around the vacuum generation part. Otherwise, there is a problem that the exhaust resistance between the hand and the wafer increases and the adsorption power decreases.

  On the other hand, in a hand that does not require the wafer to be lifted, it becomes a factor that increases the thickness beyond the necessary plate thickness in terms of strength, and hinders thinning. In addition, it is necessary to provide a separate contact holding portion such as a pad that is higher than the flying height of the wafer, which increases the thickness of the hand.

  Assuming a specific preferable thickness of the hand, when a wafer with a warp is held by a hand using the Bernoulli effect, the thickness of the cassette to be accommodated is equal to or greater than a predetermined pitch (eg, 4.76 mm). Random access will be hindered. For this reason, a hand having a thickness of 2 mm or less is required in order to attract a warped wafer. Further, in the non-contact holding hand, the compressed air that generates the vortex is exhausted in a random direction into the gap with the wafer, and therefore, there is a possibility that the random exhaust flow in the cassette may have an unexpected adverse effect on the wafer.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and to discharge the fluid in which the vortex flow is generated from the cylindrical side surface in a predetermined controlled direction and to bring the wafer into contact with the hand. Accordingly, it is an object of the present invention to provide a structural substrate holding device that holds a wafer by applying only a negative vortex pressure.

In order to achieve the above object, the present invention provides a hand main body in which an air supply path is formed up to a tip portion holding a substrate, and is formed integrally with the hand main body at the tip portion of the hand main body to hold the substrate. An air nozzle that has an open inner recess, and that opens along a direction circumscribing the inner peripheral surface of the inner recess so that the inner recess communicates with the air supply path, and the hand body internal between the outer wall of which is formed by notching, along said direction circumscribing the inner peripheral surface of the inner recess and a suction portion and a discharge port opened is provided, wherein from the error anode nozzle while injecting air into the recess, to circulate air along the inner circumferential surface of the inner recess part of the air that is injected and evacuated toward from the exhaust port on a side surface outside of the suction unit generates a vortex Te, circumferential said substrate open faces of the inner recess Wherein the contact held in the part.

In the internal recess, it is preferable that a ring-shaped plate material in contact with the substrate is attached along a peripheral edge portion of the open surface, and one surface of the exhaust port is covered.

The angle formed by the air injection direction of the air nozzle formed at a predetermined position on the inner peripheral surface of the internal recess and the exhaust direction of the exhaust port to the outside of the side surface of the hand body is set to 135 to 180 °. Is preferred.

  Preferably, a plurality of air nozzles and at least one exhaust port are formed at predetermined positions on the inner peripheral surface of the internal recess.

  According to the present invention, since the wafer held in contact with the hand is held by applying only the negative pressure of the vortex, the hand can be made thin, and a warped substrate or the like can be reliably held. Has an effect.

The top view which showed the hand by one Example of the board | substrate holding apparatus of this invention. The perspective view which showed the hand shown in FIG. FIG. 5 is a partially enlarged plan view, a cross-sectional view, and an end view showing an enlarged suction part of the hand shown in FIG. 4. Explanatory drawing which showed the example of arrangement | positioning of the exhaust port provided in the adsorption | suction part of a hand. The partial enlarged plan view which showed the modification of the adsorption | suction part of a hand.

  Hereinafter, the form for implementing the board | substrate holding apparatus of this invention is demonstrated with reference to FIGS. 1-3. FIG. 1 is a plan view showing a hand of a substrate holding apparatus of the present invention. 2 is a perspective view showing the hand in a stereoscopic view, and FIG. 3 is an enlarged plan view, a partial cross-sectional view, and a partial end view showing the suction part of the hand shown in FIG. 1 in an enlarged manner.

  As shown in FIGS. 3B and 3C, the hand 10 as the substrate holding device of the present invention has two identical flat plates 11 (in the case of distinction, the base plate 11a). , And referred to as a bottom plate 11b). The hand 10 is attached to the tip of a swivel arm such as a transport robot (not shown), and an air supply unit led to the tip of the swivel arm (not shown) is connected to an air supply hole 12a formed at the base of the hand 10. As shown in FIG. 1, the hand 10 of this embodiment is positioned at a base portion 10 a and both ends of the base portion 10 a, and a small-diameter wafer 1 is attached to the tip suction portion 12 (detailed configuration will be described later). The two support hands 10b to be sucked and held are integrally formed and have a substantially U shape in plan view. The wafer 1 can be moved to a predetermined position by a turning and extending / bending operation of a turning arm (not shown) to which the root portion 10a is attached.

  At the tips of the two support hands 10b that are symmetric with respect to the central axis C, a substantially circular suction portion 12 is provided in plan view where the wafer 1 can be directly mounted. The suction portion 12 has a substantially circular shape in plan view, and a circular recess 13 having a flat cylindrical shape with an open upper surface is formed in the central portion. Further, the outer peripheral edge of the circular recess 13 circumscribes the inner peripheral surface of the circular recess 13 and serves as an exhaust port 16 so as to penetrate the ring-shaped peripheral portion 12d of the suction portion 12 at a predetermined angle. A functioning notch 13a is formed. In the present embodiment, the circular recess 13 is set to have a diameter of 20 mm, a depth of 1.2 mm, and a width of the notch 13a of 3.5 to 4.0 mm. The circular recess 13 is configured such that a part of the base plate 11a passes through a circle having a predetermined diameter, and the bottom plate 11b is addressed so as to be a bottom surface. The air supply flow rate into the circular recess 13 having the above-described dimensions is set to about 20 l / min. The dimensions of each part of these suction parts 12 can be set variously, and the loading speed of the hand can be adjusted by adjusting the exhaust speed and flow rate of air, which will be described later, according to the set values. It is also preferable to adjust the air supply amount. For example, by setting the amount of air supplied to the suction unit 12 having the above dimensions to about 80 l / min, the suction unit 12 can hold a wafer having a diameter of about 300 mm.

  On the other hand, as shown in FIG. 1, an air supply path 12c extending from the air supply hole 12a at the base portion to the suction portion 12 is formed in the support hand 10b. In this embodiment, a square groove 12b set to a predetermined depth and width (in this embodiment, a depth of 0.7 mm and a width of 3.0 mm) is formed on the surface of the base plate 11a, and the square groove 12b is formed. An air supply path 12c having a square cross section is formed by covering the formed surface with the bottom plate 11b. In the present embodiment, an aluminum plate having a thickness of 1.2 mm is used as the base plate 11a, and a stainless steel plate having a thickness of 0.2 mm is used as the bottom plate 11b. The square groove 12b can be easily formed by cutting the surface of the aluminum plate into a groove shape having a depth of 0.7 mm. Further, an air nozzle 15 is formed at the tip of the air supply path 12c. The air nozzle 15 is formed by narrowing the groove width of the air supply path 12c to about 1/3 (1 mm in this embodiment). Therefore, the injection pressure of the supply air is increased at this portion, and the high-pressure air is injected into the circular recess 13.

  As shown in FIG. 1 and FIG. 3A, the air nozzle 15 has a formation position and orientation so that air can be injected into the circular recess 13 from a direction circumscribing the inner peripheral surface of the circular recess 13. Is set. In the embodiment shown in FIG. 1, the direction of the air nozzle 15 facing the circular recess 13 and the forming direction of the notch 13a are set to be approximately 180 ° (opposite direction).

  Since the notch 13a is formed by notching a part of the circular suction part 12 at the tip of the support hand 10b, as shown in FIGS. 1 and 2, an acute-angled part 12e on the outer peripheral surface of the suction part 12 is formed. Is formed. The cover ring 17 is attached so as to overlap the outer portion of the circular recess 13 of the suction portion so that the surface of the wafer 1 is not damaged by the portion 12e. As the cover ring 17, a polyamide thin plate processed product is used in this embodiment.

Here, the wafer holding function of the present invention will be described with reference to FIGS. The air supplied from the air supply hole 12 a is ejected from the air nozzle 15 along the inner peripheral surface of the circular recess 13 and becomes an air flow flowing along the inner peripheral surface of the circular recess 13. A part of the air flow is exhausted to the outside of the side surface of the hand 10 from a notch 13a (exhaust port 16) formed in the direction along the inner peripheral surface of approximately 180 ° toward the air nozzle 15 facing the circular recess 13. Then, a part passes through the position of the notch 13a and further flows toward the position of the air nozzle 15 along the inner peripheral surface of the circular recess 13. As shown by a circle with an arrow schematically shown in FIG. 3A, the air nozzle 15 passes through the position and rotates clockwise in the circular recess 13 (counterclockwise in the suction part of the other support hand). It becomes a swirling vortex. While this vortex flows at a predetermined flow velocity, a part of the air is exhausted from the notch 13a (exhaust port 16) , and a negative pressure is generated in the circular recess 13. When the wafer 1 is placed on the circular recess 13 in this state (see FIG. 1), the wafer is stabilized on the ring-shaped peripheral portion 13 by the suction force due to the negative pressure generated by the vortex flow in the circular recess 13. Is held in contact .

  In the present invention, since the peripheral edge portion 12d and the wafer 1 (FIG. 1) are in contact with each other, the generated negative pressure can be held at a low pressure, and damage to the wafer 1 during handling can be reduced. . In order to hold a wafer having a large diameter, it is possible to increase the negative pressure generated by increasing the depth of the circular recess 13. Further, by changing the width of the notch 13a as the exhaust port 16, it is possible to improve the rising of the negative pressure at a low flow rate or to generate a high negative pressure at a large flow rate.

  Next, the relationship between the angle formed by the air nozzle 15 and the exhaust port 16 and the state of vortex generation in the circular recess 13 will be described with reference to FIG. FIG. 4 is a partially enlarged plan view showing an example of an angle formed by the air nozzle 15 and the exhaust port 16 (notch 13a). In the present embodiment, the angle formed by the air nozzle 15 and the exhaust port 16 is about 180 ° and is set to be opposite to the air injection direction and the exhaust direction. As indicated by the arrows in the figure, the air flows along the inner peripheral surface of the circular recess 13 to deflect its direction by 180 °. By taking a sufficient angle between the air nozzle 15 and the exhaust port 16, the speed of the generated vortex and the air flow rate are controlled. For example, when the angle of the exhaust port 16 is a right angle (about 90 °) with respect to the air nozzle 15, since it flows along the inner peripheral surface of the circular recess 13 in the range of 90 °, it is difficult to obtain a vortex that circulates, A sufficient effect cannot be obtained. In order for the air to become a vortex that generates a negative pressure in the circular recess 13, about 135 ° with respect to the direction of the air nozzle 15 (in other words, the angle formed by the air nozzle 15 and the exhaust port 16 is about 45 ° or less). When the above is ensured, a negative pressure capable of holding an object such as a wafer in the circular recess 13 can be generated.

  Each drawing in FIG. 5 shows various modifications in which the number and arrangement of the air nozzles 15 and the exhaust ports 16 are changed in various ways so that the vortex flow is efficiently generated in the circular recess 13. The following is a brief description of each example. 5 (a) and 5 (b) show a modified example including two air nozzles 15A and 15B and one exhaust port 16A. In these modified examples, since air can be supplied from the two air nozzles 15A and 15B into the circular recess 13, a negative pressure sufficient to attract a wafer or the like can be generated. At this time, the width of the exhaust port 16A is made wider than that of the embodiment shown in FIG. 4 and the like to increase the amount of exhaust air, so that an efficient generation of vortex flow in the circular recess 13 can be achieved. The two examples differ in that the angles at which the air nozzles 15A and 15B face the circular recess 13 are different. In FIG.5 (b), the air injected from the air nozzle 15B is arrange | positioned along the tangent direction of the circular recess 13 so that the position of the exhaust port 16A may be crossed. As a result, the proportion of the air jetted from the air nozzles 15 </ b> A and 15 </ b> B that is exhausted directly from the exhaust port 16 </ b> A is reduced, and the jetted air can be efficiently swirled in the circular recess 13. Although it is assumed that the air jetted from the air nozzles 15A and 15B has the same flow rate and the same flow velocity, the flow rate and the flow velocity of both need not be equal and can be set as appropriate in order to efficiently generate a vortex. it can.

  5 (c) and 5 (d) show a modification example including two air nozzles 15A and 15B and two exhaust ports 16A and 16B. These modifications are effective when the circular recess 13 is enlarged. That is, while supplying a large amount of air from the two air nozzles 15A and 15B and efficiently exhausting air from the two exhaust ports 16A and 16B, it is possible to maintain the flow velocity of the vortex that circulates greatly, This makes it possible to generate a negative pressure sufficient to attract a wafer having a large diameter (in other words, a large mass). FIG. 5D shows the air jetted from the air nozzle 15B in FIG. 5B along the tangential direction of the circular recess 13 so as to cross the position of the exhaust port 16B. As a result, the proportion of the air ejected from the air nozzle 15 </ b> B is directly exhausted from the exhaust port 16 </ b> B, and the ejected air can be efficiently vortexed in the circular recess 13.

  FIG. 5E is a modification in which the shape of the recess 13B of the suction portion 12 is a hexagon. When the inner circumferential surface is a polygonal surface such as a hexagonal shape, the flow velocity of the vortex is initially reduced compared to the case of the circumferential surface. Since the buffer by the stagnant air can be formed, it can be expected that the flow velocity of the vortex circulating in the recess 13B is recovered and a holding force close to that of the circular recess is exhibited.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope indicated in each claim. In other words, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Hand 11 Flat plate 12 Adsorption part 13 Circular recess 13a Notch 13b Peripheral part 15, 15A, 15B Air nozzle 16, 16A, 16B Exhaust port

Claims (4)

A hand body in which an air supply path is formed up to the tip portion holding the substrate;
The hand body has an internal recess formed integrally with the hand body at the tip portion of the hand body, and the surface for holding the substrate is open, and the internal recess is communicated with the air supply path. The air nozzle that opens along the direction of circumscribing the inner peripheral surface of the hand and the outer wall surface of the hand body, and that opens along the direction of circumscribing the inner peripheral surface of the internal recess. An adsorption part provided with an exhaust port ;
With
While injecting air into the inner recess from the d anode nozzle, the inner peripheral surface of the inner recess part of the injected air from the exhaust port to exhaust towards the sides outside of the suction unit A substrate holding device characterized in that air is circulated along the surface to generate a vortex and the substrate is held in contact with the peripheral edge of the open surface of the internal recess . 2. The substrate holding apparatus according to claim 1, wherein the internal recess is attached with a ring-shaped plate material in contact with the substrate along a peripheral edge portion of the open surface, and one surface of the exhaust port is covered . The angle formed by the air injection direction of the air nozzle formed at a predetermined position on the inner peripheral surface of the internal recess and the exhaust direction of the exhaust port to the outside of the side surface of the hand body is 135 to 180 °. The substrate holding device according to claim 1 or 2.   4. The substrate holding apparatus according to claim 1, wherein a plurality of air nozzles and at least one exhaust port are formed at predetermined positions on the inner peripheral surface of the internal recess. 5.

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