WO2002047155A1 - Holder - Google Patents

Abstract

The invention relates to a noncontact holder using Bernoulli's theorem to hold a silicon wafer, for example. A plate face (5) includes a recess (6a) with a spout (9) such that the jet from the spout (9) makes an angle greater than 90 degrees and smaller than 180 degrees with the recess wall. The recess wall and the plate face (5) make an angel greater than 90 degrees and smaller than 180 degrees. This structure stabilizes the velocity of the fluid passing along the plate face (5) and stabilizes the negative pressure produced on the plate face, with the result that stable attraction is produced.

Description

 Holder Technical field

 According to the present invention, a negative pressure is generated by the Bernoulli effect of a fluid so that a semiconductor wafer or the like is exposed to a negative pressure.

(5) The present invention relates to a holder for holding a holder while keeping the holder in a non-contact state. Background art

 Conventionally, there has been known a holder that uses a Bernoulli effect of a fluid to generate a negative pressure in a gap between a plate surface and a held body, and holds the held body in a non-contact state by the negative pressure. Have been.

 However, in the above-mentioned holder, when the holding object is not held, the ejected fluid tends to diffuse in the normal direction of the plate surface, and blows the holding member when the holder approaches the plate surface. There was an inconvenience. In addition, since the suction force depends on the flow velocity of the fluid flowing through the gap between the plate surface and the holder, there is a problem that if the gap between the plate surface and the holder changes, the suction force also varies.

 Therefore, as a means of solving these problems, for example, there is a method disclosed in Japanese Patent Application Laid-Open No. 10-167470.

 In this conventional example, as shown in FIG. 11, a plate body a having a circular plate surface 1 is provided with a suction port 2 for sucking a fluid, and a plurality of jet ports arranged concentrically around the suction port 2. 30.

 A curved surface is formed in the opening 2a of the suction port 2, and the suction port 2 and the plate surface 1 are smoothly connected.

 In addition, a curved surface is also formed in the opening 3a of the discharge port 3, and the discharge port 3 and the plate surface 1 are smoothly connected.

 25 When a fluid such as gas is ejected from the ejection port 3, the fluid is guided to the plate surface 1 along the curved surface of the opening 3a by the Coanda effect, and the ejection flows inward. A part of the fluid is sucked through the suction port 2.

 When the fluid ejected from the ejection port 3 flows along the plate surface 1 as described above, a negative pressure is generated near the plate surface 1 due to the Bernoulli effect of the fluid. Utilizing this negative pressure, the object to be held 4 is held while maintaining a non-contact state.

 In the above-mentioned conventional example, a passage for ejecting a fluid and a passage for sucking the sucked fluid must be formed in the plate body a, so that the structure becomes complicated, and a plate having such a passage is actually provided. It was very difficult to form body a.

The negative pressure caused by the Bernoulli effect is the pressure of the fluid passing through the plate surface. Although it varies depending on the flow rate, this flow rate varies not only with the discharge amount of the fluid discharged from the outlet 3 but also with the balance of the suction amount of the fluid sucked from the suction port 1. Has become. Since the flow velocity passing through the plate surface 1 is thus unstable, there is also a problem that it is difficult to control the negative pressure, that is, the suction force generated by the flow velocity.

 Further, in this conventional example, a mechanism for sucking the fluid is required in addition to the mechanism for ejecting the fluid, so that there is a problem that the whole apparatus becomes large accordingly.

 An object of the present invention is to provide a low-cost holding device which has a simple structure, can control the suction force stably, and has a low cost. Disclosure of the invention

 According to a first aspect of the present invention, there is provided a main body having a plate surface, a concave portion formed on the plate surface of the main body, and a jet port provided in the concave portion and jetting a fluid such as gas. By guiding the ejected fluid along the plate surface, a negative pressure is generated on the plate surface according to Berne's principle, and the holder uses the negative pressure to hold the object in a non-contact state. A throttle is provided at the jet port, the fluid is accelerated by the throttle port, and the jet direction of the jet fluid intersects the wall surface of the concave portion, and the jet direction of the fluid and the wall surface of the concave portion intersect with each other. The angle formed between the concave wall surface and the plate surface is set to 90 degrees or more and less than 180 degrees while the angle formed by the angle is greater than 90 degrees and less than 180 degrees.

 A second invention is characterized in that, in the first invention, an arc or chamfer is formed at a part of the corner where the wall surface of the concave portion and the plate surface intersect.

 A third invention is characterized in that, in the first invention or the second invention, an arc or chamfer is formed in a part of an outer edge of the plate surface. _

 A fourth invention is characterized in that, in the first to third inventions, a space is provided between the throttle outlet and the bottom surface of the concave portion, and this space promotes the adhesion of the ejected fluid to Coanda. I do. A fifth invention is characterized in that, in the first to fourth inventions, the shape of the opening of the aperture outlet is extended in parallel with the plate surface to form a slit.

 According to a sixth aspect, in the first to fifth aspects, a guide member that extends outward is provided on an outer periphery of the plate surface, and the guide surface of the guide member is inclined with respect to the plate surface. It is characterized by an octopus.

0

 Brief description of the drawings ''

1 is a cross-sectional view of the first embodiment, FIG. 2 is an enlarged cross-sectional view of a main part of FIG. 1, and FIG. 3 is a cross-sectional view showing a state before assembly of the second embodiment. FIG. 4 is a cross-sectional view showing the assembled state of the second embodiment, FIG. ₅ is a cross-sectional view ₅ showing the state before the assembly of the third embodiment, and FIG. FIG. 7 is a cross-sectional view showing an assembled state of the third embodiment, FIG. 7 is a cross-sectional view of a main part of the fourth embodiment, and FIG. 8 is a cross-sectional view of a main part of the fifth embodiment. , Fig. 9 FIG. 10 is a side view of the embodiment, FIG. 10 is a plan view of the sixth embodiment, and FIG. 11 is a cross-sectional view of the conventional example. BEST MODE FOR CARRYING OUT THE INVENTION

 In the first embodiment shown in FIGS. 1 and 2, a hole 6 is formed in the center of a main body A having a circular plate surface 5 and a tape gradually widens from the hole 6 toward the plate surface 5. One taper surface is formed, and the taper surface is the concave portion 6a of the present invention.

 A nozzle member 7 is incorporated in the hole 6. The nozzle member 7 has one surface 7a at the same level as the plate surface 5 and has a supply hole 8 formed therein. A plurality of throttle outlets 9 continuous with the supply holes 8 are formed radially.

 The throttle outlet 9 is formed parallel to the plate surface 5 and has a diameter smaller than that of the supply hole 8. By thus narrowing the flow path, the total flow area of the plurality of throttle jets 9 is made smaller than the flow area of the supply hole 8.

 The opening of the throttle outlet 9 is circular.

5 Although not shown, a pipe for guiding a fluid such as air is connected to the supply hole 8. When air is led to the supply hole 8 through this pipe, the air is led to the plurality of throttle injection ports 9. At this time, since the total flow area of the plurality of throttle injection ports 9, that is, the effective cross-sectional area of the flow path is made smaller than the effective cross-sectional area of the flow path of the supply hole 8, the supply ^: 8 In the process of passing through 9, the flow velocity accelerates several times to over ten times. As shown in FIG. 2, the fluid 0 sufficiently accelerated in this manner is sprayed onto the recess 6a with an angle.

 The air blown to the concave portion 6a at the angle α is guided along the concave portion 6a by the Coanda effect, and then is guided to the plate surface 5 from the concave portion 6a.

 Further, the fluid guided along the plate surface 5 is guided to the side surface 16 along the corner 15 at the outer edge of the plate surface, as shown in FIG. 1, and is discharged downward in the drawing.

 5 When the fluid accelerated and accelerated as described above flows along the plate surface 5, a sufficient negative pressure is generated on the plate surface 5 due to the Bernoulli effect of the fluid. By using this negative pressure, an object (not shown) placed at a predetermined distance from the plate surface 5 can be held while maintaining a non-contact state.

 The held body is kept in non-contact state because the ejected fluid hits the held body.

This is because thrust is given by 30. In other words, the held body is held while maintaining the non-contact state by the balance between the thrust given by the ejected fluid and the suction force due to the negative pressure generated on the plate surface 5.

In the first embodiment as described above, the fluid ejected in parallel with the plate surface 5 is once applied to the tapered recess 6a, and then is made to follow the plate surface 5, so that the fluid Coanda effect is reduced. More demonstrated. That is, the angle α at which the ejected fluid hits the concave portion 6a is larger than 90 degrees and less than 180 degrees, and the larger the larger, the more the Coanda effect is exerted. And the flow along the recess 6a can be generated.

 In addition, the flow along the concave portion 6a is caused by a force whose direction is changed by a corner portion 1 ° where the concave portion 6a and the plate surface 5 intersect, and the angle ^ of the corner portion 10 is 90 ° or more. 1

If it is less than 80 degrees, the larger it is, the more easily the Coanda effect can be exhibited.

 That is, as the angle 5 approaches 180 degrees, the fluid guided along the concave portion 6a can be efficiently guided to the plate surface 5.

 The angle α at which the ejected fluid hits the concave portion 6a is set within the range of more than 90 degrees and less than 180 degrees unless the angle falls within this range. This is because it becomes impossible to make the fluid follow the water efficiently.

 In addition, the reason why the angle 5 of the corner 10 where the recess 6 a and the plate surface 5 intersect was set to 90 degrees or more was that when the angle was less than 90 degrees, the Coanda effect was weakened and led along the recess 6 a. This is because the fluid cannot efficiently follow the plate surface 5.

 On the other hand, if the corner portion 10 is subjected to an arc or chamfering process, the fluid can be more efficiently guided along the plate surface 5 when the fluid transfers from the concave portion 6a to the plate surface 5. it can.

 If a part of the outer corner 15 of the plate 5 is also arced or chamfered, the fluid flowing along the plate surface 5 is efficiently guided to the side surface 16 and the fluid is finally Can be released downward. By discharging the fluid downward as described above, it is possible to effectively prevent dust and the like from adhering to the held member. In other words, it is most suitable when the object to be held is a semiconductor wafer that dislikes dust or the like.

 According to the first embodiment, since a predetermined suction force can be obtained only by ejecting the accelerated fluid, there is no need for a suction passage for sucking the fluid.

 Therefore, the structure can be simplified.

 Further, since there is no need to suction fluid, a suction mechanism is not required, and the cost of the entire apparatus can be reduced.

 Furthermore, since the accelerated jet fluid is guided to the plate surface 5 after one end along the concave portion 6a, the Coanda effect of the fluid can be more exerted, and the fluid is stably applied to the plate surface 5. Can be led. Since the fluid can be stably guided to the plate surface 5 in this manner, the negative pressure determined by the flow velocity flowing along the plate surface 5, that is, the suction force can be stabilized.

 On the other hand, since the ejected fluid ejected in parallel to the plate surface 5 is guided from the recess 6a to the plate surface 5, the ejected fluid does not directly act on the held member.

 If the ejected fluid is configured to act on the held body, when the amount of ejected flow acting on the held body is changed, the thrust generated by the ejected fluid and the suction force caused by the negative pressure There is a possibility that the balance may be lost and the held object may not be held.

However, according to the first embodiment, the fluid ejected from the throttle ejection port 9 flows directly to the held body. Since it does not act, such a problem can be prevented.

 Further, according to the first embodiment, since the fluid sufficiently accelerated from the throttle outlet 9 is efficiently attached to Coanda on the plate surface 5, the Bernoulli effect is sufficiently exhibited. Therefore, a negative pressure can be generated even when there is no held object above the plate surface 5. In addition, since the jet fluid is used efficiently, the jet flow rate can be reduced. By reducing the jet fi, the energy consumption of the whole equipment can be reduced.

 In the second embodiment shown in FIGS. 3 and 4, a supply passage 11 for guiding a fluid such as air is formed in a main body A, one end of which is opened to a hole 6 and the other end is opened to a side surface 16. Let me. In addition, a supply hole 13 formed in the nozzle member 12 is opened to the side in accordance with the supply passage 11.

 Then, as shown in FIG. 4, when the nozzle member 12 is incorporated into the hole 6, the supply passage 11 and the supply hole 13 communicate with each other.

 According to the second embodiment, since the pipe for guiding the fluid can be connected to the side surface 16 of the main body A, the overall thickness of the main body A can be reduced. That is, in the first embodiment, since the pipe for guiding the fluid was connected to the lower surface of the main body A, the overall thickness could not be reduced so much.

 However, according to the second embodiment, by connecting a pipe to the bristle surface 16 of the main body A, the overall thickness can be suppressed to the thickness of the main body A.

 In the third embodiment shown in FIGS. 5 and 6, the main body A is constituted by two members A 1 and A 2, and the supply passage 14 is formed on the mating surface of these two members.

 The member A1 has a groove 17 formed on the lower surface thereof, and the member A2 has a through hole 18 formed therein.

 The nozzle member 19 has a groove 20 communicating with the supply hole 8.

 Then, as shown in FIG. 6, when the nozzle member 13 is incorporated into the hole 6 and the member A 1 and the member A 2 are bonded together, a supply passage 14 is formed between the two members A 1 and A 2. One of them communicates with the through hole 18, and the other communicates with the supply hole 8 via the groove 20.

 According to the third embodiment, the supply passage 14 can be formed without using a drill or the like. Since the diameter of the supply passage 14 is small, when the supply passage is to be formed in the main body A later by using a drill or the like as in the second embodiment, the drill may be broken. is there. As a result, drilling is time-consuming and increases the processing cost.

 However, according to the third embodiment, since it is not necessary to drill a hole using a drill or the like, the additional cost can be reduced.

In the fourth embodiment shown in FIG. 7, the nozzle member 22 is fixed to the bottom of the mortar-shaped recess 21a. The angle α at which the ejected fluid hits the concave portion 21a is increased. That is, as shown in Fig. 7, the outlet 23 is directed toward the plate surface 5 and the angle α is increased. I am trying to.

 If the angle α at which the ejected fluid collides with the concave portion 21a is increased, the Coanda effect is more exerted, so that the ejected fluid can efficiently follow the concave portion 21a.

 Therefore, similarly to the first embodiment, the ejected fluid can stably follow the plate surface.

 In the fifth embodiment shown in FIG. 8, a space 25 is formed at the bottom of the concave portion 6a, that is, between the bottom surface of the concave portion of the present invention and the throttle outlet 9.

 When the space 25 is provided in this manner, the ejected fluid is drawn downward by the negative pressure generated in the space 25. Then, the fluid drawn downward is guided to the plate surface 5 side along the concave portion 6a.

 According to the fifth embodiment, the ejected fluid is attracted downward, thereby promoting Coanda attachment. Therefore, the ejected fluid can be surely made to follow the concave portion 6a.

 In the sixth embodiment shown in FIGS. 9 and 10, the tip of the nozzle 27 of the air gun 26 is fixed to the center of the I have. The air outlet of the air gun 26 communicates with the supply 6 of the nozzle member 7.

 As shown in FIG. 10, a guide member 28 extending outward is fixed to the outer periphery of the main body A at four places. These guide members 28 have their guide surfaces 28 a inclined with respect to the plate surface 5.

 In the sixth embodiment as described above, when a fluid is ejected from the air gun 26, the accelerated fluid flows along the plate surface 5, and a negative pressure is generated there. Therefore, the held body 30 can be sucked and held by utilizing the negative pressure generated on the plate surface 5. Further, since the guide member 28 is fixed to the outer periphery of the main body A, as shown in FIG. 9, when the held body 30 is sucked, a part of the corner 30a of the held body is brought into contact with the guide surface 3a. Touch 0 a. When the corner portion 30a of the held body comes into contact with the guide surface 28a in this manner, the translation of the held body 30 can be restricted. In other words, without the guide member 28, the translation of the held body 30 in the non-contact state cannot be restricted. However, according to the sixth embodiment, the held body 3 Zero translation can be restricted.

 In addition, since a part of the corner 30a of the held body 30 is brought into contact with the guide surface 28a, the surface of the held body 30 is prevented from being scratched by the guide member 38 or the like. it can. Furthermore, since the position of the held object is easily shifted by inclining the guide surface 28a, even if the center of the held object 30 and the center of the main body A are shifted at the time of suction, the suction is performed. Later, the centers can be automatically matched.

 In this way, the center of the main body A and the held body can be made to coincide with each other, so that when the main body A is fixed to the arm of the mouth bot, the accuracy of the assembling work can be improved.

On the other hand, the upper air gun 26 is generally provided as equipment in factories. Therefore, as in the sixth embodiment, the configuration is such that the main body A is attached to the tip of the air gun 26. Then, a non-contact type holder can be easily obtained. In the sixth embodiment, the guide member 28 is provided at four places of the main body A. However, the guide member 28 may be at three places or more, and may be annular.

 In the first to sixth embodiments, the opening shape of the throttle outlets 9 and 23 is circular. The shape of the opening is not limited to a circle. For example, the openings of the throttle outlets 9 and 23 may be formed in a slit shape by extending in the direction parallel to the plate surface. If the shape of the opening of the throttle outlet is made in a slit shape as described above, the fluid can be blown out in a wide range, and the fluid can be more uniformly guided to the plate surface. If the fluid is evenly introduced to the plate surface in this way, a uniform negative pressure is generated on the entire plate surface, so that the suction force is stabilized.

 The throttle outlet may have a structure like a bench lily tube, and the throttle outlet may be a choke throttle or an orifice throttle. In any case, the throttle outlet only needs to have a function of accelerating the fluid. Industrial applicability

 According to the first aspect of the present invention, a predetermined suction force can be obtained by spraying the accelerated fluid onto the wall surface of the concave portion at a predetermined angle. Therefore, the structure is simpler than that of the conventional example in which the fluid must be suctioned. Can be

 In addition, since the fluid is sprayed onto the concave wall surface at an angle of 90 degrees or more and less than 180 degrees, and the fluid is guided along the concave wall surface, the fluid flows through the plate surface. Speed can be stabilized. Since the flow velocity of the fluid passing through the plate surface can be stabilized in this manner, the resulting negative pressure, that is, the suction force can be stably controlled.

 Furthermore, since only the accelerated fluid is ejected, the cost of the entire apparatus can be reduced as compared with a holder that sucks fluid.

 According to the second aspect, since the arc or the chamfer is formed at the corner where the concave wall surface and the plate surface intersect, the fluid from the concave wall surface can be efficiently guided to the plate surface side. According to the third aspect, since the arc or the chamfer is formed in a part of the outer edge of the plate surface, the fluid passing through the plate surface can be guided to the side surface of the main body.

 According to the fourth aspect of the present invention, since the space provided between the throttle outlet and the bottom surface of the concave portion is configured to promote the adhesion of the ejected fluid to Coanda, the ejected fluid can be reliably guided along the wall surface of the concave portion. .

 According to the fifth aspect, the opening of the throttle outlet is formed in a slit shape by extending in parallel with the plate surface, so that fluid can be blown out evenly over a wide range.

 If the fluid is blown out evenly over a wide range, a uniform flow is generated on the plate surface, and a uniform negative pressure is generated on the plate surface.

Therefore, the suction force is stabilized as a whole. According to the sixth aspect, the guide member can restrict the movement of the held body parallel to the plate surface.

 In addition, since the guide surface of the guide member is inclined and the position of the held member is determined by the inclined guide surface, the portion where the guide member contacts the held member can be reduced. Since the contact surface between the held member and the guide member can be reduced in this manner, the held member is not damaged.

Claims

The scope of the claims 1. A main body having a plate surface, a concave portion formed on the plate surface of the main body, and a jet port provided in the concave portion and jetting a fluid such as gas. 5 By guiding the body along the plate surface, a negative pressure is generated on the plate surface by Bernoulli's principle, and the holding device that holds the held object in a non-contact state using this negative pressure A throttle is provided, the fluid is accelerated by the throttle outlet, and the jet direction of the jet fluid intersects the wall surface of the concave portion, and the angle between the jet direction of the fluid and the wall surface of the concave portion is 90 °. A holder, wherein the angle between the recess wall surface and the plate surface is set to 90 degrees or more and less than 180 degrees while being larger than 180 degrees and less than 180 degrees.  2. The holder according to claim 1, wherein an arc or a chamfer is formed at a part of a corner where the wall surface of the concave portion and the plate surface intersect.  3 ········································ The claim according to claim 1 or 2, characterized in that an arc or chamfer is formed at a corner of an outer edge of the plate surface. 5. A method according to any one of claims 1 to 3, wherein a space is provided between the throttle outlet and the bottom surface of the concave portion, and the space facilitates the attachment of Coanda to the ejected fluid. Holder. 5. The holder according to any one of claims 1 to 4, wherein the shape of the opening of the aperture outlet is extended in parallel with the plate surface to form a slit.  6. A guide member which spreads outward on the outer periphery of the plate surface, and the 20 guide surfaces of the guide member are inclined with respect to the plate surface. A holder according to item 1.